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State-of-the-Art Earth Sciences and Geography in China

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Earth Sciences".

Deadline for manuscript submissions: 31 December 2025 | Viewed by 47972

Special Issue Editors

Prof. Dr. Hua Zhong

E-Mail Website
Guest Editor
School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan, China
Interests: transport and transformation of contaminants in natural porous media; soil and groundwater remediation; colloid and nanoparticle transport; ISCO; SEAR
Special Issues, Collections and Topics in MDPI journals
Dr. Difei Zhao

E-Mail Website
Guest Editor
Artificial Intelligence Research Institute, China University of Mining and Technology, Xuzhou 221000, China
Interests: unconventional oil and gas geology; AI+ energy technology; sedimentary petrology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

With the rapid development of China’s geography, surveying, and mapping in recent years, Chinese researchers have made significant progress in earth sciences research and technological development fields, etc. We would like to invite authors to submit original research articles or review articles on the latest research advances in both basic theoretical research and the interdisciplinary as well as technical application of geography. We hope that all published papers will be widely read and highly influential in the field.

The topics of interest for this Special Issue include, but are not limited to, the following:

  • Remote sensing;
  • Geoinformatics;
  • Geohazards;
  • Geochemistry;
  • Geophysics;
  • Geology;
  • Geosciences;
  • Mineral resources;
  • Geotechnical engineering;
  • Marine geoscience;
  • Hydrological and hydrogeological sciences;
  • Environmental contamination;
  • Climate studies;
  • Big data;
  • Artificial intelligence.

Prof. Dr. Hua Zhong
Dr. Difei Zhao
Guest Editors

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Published Papers (28 papers)

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Research

11 pages, 3260 KiB  
Article
Geochemical Classification of Shale Based on Compositional Data: An Illustration in Southern Sichuan Area, China
by Jinghan Wei, Weixuan Gu, Qingjie Gong, Xianfu Zhu, Guoling Jia and Taotao Yan
Appl. Sci. 2025, 15(8), 4272; https://doi.org/10.3390/app15084272 - 12 Apr 2025
Viewed by 246
Abstract
The classification of shale is commonly based on lithofacies structure, mineral content, organic carbon content, physical and chemical parameters, and element contents. A geochemical classification method based on the compositional data of shale is proposed which divides shale, sedimentary rocks, sediments, and soils [...] Read more.
The classification of shale is commonly based on lithofacies structure, mineral content, organic carbon content, physical and chemical parameters, and element contents. A geochemical classification method based on the compositional data of shale is proposed which divides shale, sedimentary rocks, sediments, and soils into six types, named siliceous, felsic, silicate, calcsilicate, dolomitic, and calcareous components, and numbered from type 1 to type 6, respectively. Sedimentary rocks in China, including mudstone (shale), sandstone, carbonate rocks, and siliceous rocks, are selected to test the method, and the results show that the method can accurately classify not only shale but also other sedimentary rocks. Shale samples from a drill well in southern Sichuan area are classified based on the proposed method as an illustration in a line graph. Furthermore, the stream sediments and soils from geochemical survey projects in the southern Sichuan area are also classified based on their compositional data. Based on the classification results, a geochemical map is drawn and compared with the strata lithology. These results indicate that the new classification method is suitable for shale, sedimentary rocks, sediments, and soils, and illustrates clear geochemical properties based on their classified types. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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27 pages, 75384 KiB  
Article
Experimental Investigation of the Normal Coefficient of Restitution in Rockfall Collisions: Influence and Interaction of Controlling Factors
by Ran Bi and Zhao Han
Appl. Sci. 2025, 15(7), 3874; https://doi.org/10.3390/app15073874 - 1 Apr 2025
Viewed by 253
Abstract
Rockfalls pose significant threats to infrastructure, transportation routes, and human safety in mountainous regions, making them a critical concern in natural hazard and risk management. Accurate prediction of rockfall behavior is essential for designing effective mitigation strategies. The normal coefficient of restitution ( [...] Read more.
Rockfalls pose significant threats to infrastructure, transportation routes, and human safety in mountainous regions, making them a critical concern in natural hazard and risk management. Accurate prediction of rockfall behavior is essential for designing effective mitigation strategies. The normal coefficient of restitution (Rn) is a key kinematic parameter for modeling falling rock dynamics, specifically quantifying the energy retained after collision between a rock and a slope surface. While this parameter is not directly used in prevention design, it is crucial for predicting the movement and trajectory of falling rocks and can indirectly support the development of more effective hazard mitigation strategies. However, Rn is influenced by multiple factors, including slope angle, surface material, falling rock shape, and initial velocity. The interactions among these factors make a precise prediction of Rn particularly challenging. Existing theoretical and empirical formulas typically consider individual factors in isolation, often neglecting their interactions, which leads to significant discrepancies in the results. To address this gap, we conducted a series of laboratory physical model tests to investigate the interactions among highly sensitive controlling factors and improve the accuracy of Rn prediction. A self-designed release apparatus, coupled with a high-speed recording and analysis system, was used to capture full kinematic data during rockfall collisions on slopes. This study not only examined how the main controlling factors and their interactions affect Rn but also developed a multi-factor interaction regression model, which was verified using on-site test data. The results show that the effect of the main controlling factors decreases in the following order: falling rock shape, slope surface material, initial velocity, and slope angle. Considering that falling rock shape and slope surface material cannot be quantitatively evaluated, the shape factor (η) and material factor (Aslope) are proposed to represent two controlling factors, respectively. Specifically, increases in η, Aslope, initial velocity, and slope angle are negatively correlated with Rn. Highly significant interactions were observed among falling rock shape–slope surface material, falling rock shape–initial velocity, falling rock shape–slope angle, slope surface material–initial velocity, and falling rock shape–slope surface material–initial velocity. These interactions mitigate the Rn reduction, resulting in a weaker effect than the stacking effect of the individual factors. The phenomenon is primarily attributed to the fact that high-level η, Aslope, initial velocity, and slope angle diminish the effect of intersecting factors. Finally, a comparison of the multi-factor interaction model with on-site tests and empirical formulas revealed the accuracy of the proposed model. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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13 pages, 9167 KiB  
Article
Geochemical Survey in Mojiang Area of Yunnan Province, China: Geochemical Map and Geochemical Anomaly Map
by Xianfu Zhu, Peiyu Li, Qingjie Gong, Weixuan Gu, Shengchao Xu and Taotao Yan
Appl. Sci. 2025, 15(5), 2592; https://doi.org/10.3390/app15052592 - 27 Feb 2025
Viewed by 371
Abstract
The geochemical maps and geochemical anomaly maps produced based on the data in the databases of the Regional Geochemistry–National Reconnaissance (RGNR) and the National Multipurpose Regional Geochemistry Survey (NMPRGS) projects have played a crucial role in China’s geochemical exploration. A geochemical survey of [...] Read more.
The geochemical maps and geochemical anomaly maps produced based on the data in the databases of the Regional Geochemistry–National Reconnaissance (RGNR) and the National Multipurpose Regional Geochemistry Survey (NMPRGS) projects have played a crucial role in China’s geochemical exploration. A geochemical survey of the Mojiang area, Yunnan Province, China, has been completed and reveals potential new regions for Ni exploration related to occurrences of serpentinite melanges. The geochemical maps and geochemical anomaly maps need to be drawn in this area. Traditional geochemical maps, heavily dependent on data quantity, are less suitable for consistent comparisons across distinct regions and elements. Here, a fixed value method is proposed to contour the Ni geochemical map on 19 levels, which is convenient for the comparison among elements. On the geochemical maps, the two known Ni deposits are located in a region with Ni surely screening risk level (on the national standard of pollution risk of heavy metals in China) and a region with Ni economic level (Ni as an associate or main economic metal on the national standard of Ni deposit in China), respectively. In addition, we have determined that the Sn and Li levels in this area are at (low or high) background levels compared to other regions. Then, the method of seven levels of classification, which is also suitable for the comparison across different areas or elements, is used to draw the geochemical anomaly maps in the Mojiang area. On the anomaly maps, the two known Ni deposits are located in the regions with Ni anomaly levels not less than four, while the anomaly areas of Sn and Li are sporadic, with anomaly levels not larger than two in this area. These consistent results with the known facts of Ni, Sn, and Li deposits in the Mojiang area not only consolidate the roles of geochemical maps and geochemical anomaly maps but also illustrate the comparison among elements in mineral exploration. Furthermore, we predicted three Ni potential regions in the Mojiang area on the geochemical survey. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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20 pages, 14686 KiB  
Article
Landslide Susceptibility Assessment Using the Geographical-Optimal-Similarity Model
by Yonghong Xiao, Guolong Li, Lu Wei, Jing Ding and Zhen Zhang
Appl. Sci. 2025, 15(4), 1843; https://doi.org/10.3390/app15041843 - 11 Feb 2025
Viewed by 591
Abstract
As a critical predisaster warning tool, landslide susceptibility assessment is crucial in disaster prevention and mitigation efforts. However, earlier methods for assessing landslide susceptibility have often ignored the impact of similarities in geographical attributes, restricting their feasibility in regions with diverse characteristics. The [...] Read more.
As a critical predisaster warning tool, landslide susceptibility assessment is crucial in disaster prevention and mitigation efforts. However, earlier methods for assessing landslide susceptibility have often ignored the impact of similarities in geographical attributes, restricting their feasibility in regions with diverse characteristics. The geographical-optimal-similarity (GOS) model effectively captures similarity relations within geospatial data and can isolate region-specific landslide features, thus overcoming this challenge. Consequently, a landslide susceptibility assessment method was developed by integrating the information value (IV) model with the GOS model. Huangshan City in Anhui Province, China, was selected as the study region. This research used 11 remote sensing feature factors and 657 historical landslide points, combined with the IV model, to construct a dataset for landslide prediction and susceptibility assessment using the GOS model. The findings indicate that, compared to conventional methods such as random forest, logistic regression, and radial basis function classifier, the GOS model enhances the area under the curve (AUC) value by 2.81% to 8.92%, reaching 0.846. This demonstrates superior performance and confirms the effectiveness and accuracy of the method in landslide susceptibility assessment. Furthermore, compared to the basic-configuration-similarity (BCS) model, the GOS model increases the AUC value by 9.64%, achieving 0.846. This approach substantially diminishes the effects of historical data accuracy, revealing upgraded applicability in landslide susceptibility evaluations. Landslides in Huangshan City are primarily influenced by rainfall and vegetation cover. High-susceptibility zones are predominantly located in areas with high precipitation and low vegetation cover. In contrast, low-susceptible and non-susceptible zones are primarily found in flat areas with high vegetation cover and farther from fault lines. The majority of the study region lies within landslide-prone zones, with non-susceptible areas comprising only 12.43% of the total area. Historical landslides are largely concentrated in moderate- to high-susceptibility zones, accounting for 92.24% of all landslide occurrences. Landslide density increases with the susceptibility level, with a density of 0.15 landslides per square kilometre in high-susceptibility zones. This study brings forward a reliable strategy for establishing the spatial relationship between geographical attribute similarity and landslide susceptibility, bolstering the method’s adaptability across various regions. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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14 pages, 2023 KiB  
Article
Innovative Equation for Determining the Geochemical Background Values of Chromium Based on Major Components in Rock–Soil–Sediment Systems
by Shuya Zhou, Qingjie Gong, Zhaochong Zhang, Zhendong Lv, Shaoyu Chen and Yonglong An
Appl. Sci. 2025, 15(1), 182; https://doi.org/10.3390/app15010182 - 28 Dec 2024
Cited by 1 | Viewed by 883
Abstract
The geochemical background value of chromium (Cr) serves as a pivotal factor in environmental assessments and mineral exploration endeavors. Traditionally, geochemical background values have been determined using statistical parameters derived from dataset analysis, though this method may possess inherent limitations. In this study, [...] Read more.
The geochemical background value of chromium (Cr) serves as a pivotal factor in environmental assessments and mineral exploration endeavors. Traditionally, geochemical background values have been determined using statistical parameters derived from dataset analysis, though this method may possess inherent limitations. In this study, we introduce a novel equation to calculate the geochemical background value of Cr, based on the premise that major elements can effectively delineate the geochemical background for trace elements. Using a dataset encompassing 791 abundance records from rocks, soils, and sediments, we derived and fitted the equation. Our findings revealed that when treating these 791 records as representative of background samples, approximately 95% of the records lie within a logarithmic error of ±0.2 from the calculated values. Based on this observation, we propose adopting a logarithmic error threshold of ±0.2 as a criterion for identifying background samples. To further validate the equation, we tested background samples from diverse regions with varying degrees of weathering. Among the 138 samples analyzed, only two exhibited background values with a logarithmic error exceeding ±0.2 from the measured values, although all samples fell within a ±0.3 error margin. We subsequently applied this equation to the orthopyroxenite and dunite zones within the Pados-Tundra complex, located in the western Kola Peninsula, Russia. According to the ±0.2 logarithmic error criterion, mildly altered orthopyroxenite samples could be deemed as background Cr samples, where certain altered orthopyroxenite samples exhibited a logarithmic error in the ±0.2–±0.3 range. In contrast, altered and mineralized samples in the dunite zone showed a significant deviation beyond the ±0.2 error range, indicating that they should be classified as anomalous Cr samples. This innovative methodology offers a refined approach for background determination and anomaly identification, thereby enhancing mineral exploration and Cr environmental quality assessments. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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10 pages, 1731 KiB  
Article
Evaluation of Mixed Traffic Flow Efficiency and Safety on Hard-Shoulder-Running Freeways
by Ye Zhi, Zhengping Zhang, Wenhui Zhou, Dongyang Hou and Jun Zhang
Appl. Sci. 2024, 14(23), 11137; https://doi.org/10.3390/app142311137 - 29 Nov 2024
Viewed by 755
Abstract
Most of the existing studies on the freeway hard-shoulder-running (HSR) strategy only focus on the traffic flow with human-driven vehicles (HDVs) but neglect the potential impacts of connected automated vehicles (CAVs) with various penetration rates on the macroscopic traffic flow. The purpose of [...] Read more.
Most of the existing studies on the freeway hard-shoulder-running (HSR) strategy only focus on the traffic flow with human-driven vehicles (HDVs) but neglect the potential impacts of connected automated vehicles (CAVs) with various penetration rates on the macroscopic traffic flow. The purpose of this paper is to ascertain whether the effects of mixed traffic flow for the freeway HSR strategy differ from those of a traditional traffic flow or not. In this research, a sophisticated methodology is employed, integrating microscopic simulation with factorial experimental design. By meticulously examining and statistically analyzing the simulation results, significant and novel insights are obtained. We find a complex interplay between the penetration rate of CAVs and HSR strategy on traffic flow efficiency and safety metrics. Without HSR, the traffic flow efficiency does not exhibit an immediate enhancement as the penetration rate increases. Instead, a notable improvement in overall traffic flow efficiency is observed only when the penetration rate attains a specific threshold. After implementing the HSR, the penetration rate of CAVs has a pronounced positive influence both on the traffic efficiency and safety, regardless of the prevailing traffic flow conditions. However, different speed limits for the HSR can lead to varying degrees of efficiency improvement under different traffic demands. Within a penetration rate range of 0.4 to 0.7 during the congested traffic flow, the traffic efficiency achieved at a speed limit of 120 km/h does not necessarily exceed that achieved at a speed limit of 80 km/h. Finally, we observe that the opening of hard shoulders would result in a decrease in traffic safety under congested traffic conditions. This finding provides important guidance for determining the appropriate timing of hard shoulder utilization in mixed traffic flow scenarios in the future. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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19 pages, 5915 KiB  
Article
Differentiated Interval Structural Characteristics of Wufeng−Longmaxi Formation Deep Shale Gas Reservoirs in Western Chongqing Area, China: Experimental Investigation Based on Low-Field Nuclear Magnetic Resonance (NMR) and Fractal Modeling
by Difei Zhao, Dandan Liu, Yuan Wei, Qinxia Wang, Shengxiu Wang, Xiaoyu Zou, Weiwei Jiao, Yinghai Guo and Geoff Wang
Appl. Sci. 2024, 14(11), 4733; https://doi.org/10.3390/app14114733 - 30 May 2024
Viewed by 1201
Abstract
The study of deep shale gas (>3500 m) has become a new research hotspot in the field of shale gas research in China. In this study, 16 representative deep shale samples were selected from different layers of the Wufeng–Longmaxi Formation in the Z-3 [...] Read more.
The study of deep shale gas (>3500 m) has become a new research hotspot in the field of shale gas research in China. In this study, 16 representative deep shale samples were selected from different layers of the Wufeng–Longmaxi Formation in the Z-3 well in the western Chongqing area to conduct low-field nuclear magnetic resonance (NMR) tests, field-emission scanning electron microscopy (FE-SEM) observation, and fractal modeling. By comparing the differences in pore structure and their influencing factors in representative samples from different layers, the particularities of high-quality reservoirs have been revealed. The results show that the Z-3 well shales mainly develop micropores and mesopores, with pore sizes of 1 nm–200 nm. The fractal dimensions of bound fluid pores D1 (1.6895–2.3821) and fractal dimension of movable fluid pores D2 (2.9914–2.9996) were obtained from T2 spectra and linear fitting, and the pores were divided into three sections based on the NMR fractal characteristics. TOC content was one of the major factors affecting the gas content in the study area. The shale samples in the bottom S1l1-1 sub-layer with a higher TOC content have larger porosity and permeability, leading to enhanced homogeneity of the pore structure and favorable conditions for shale gas adsorption. A comparative understanding of the particularities of pore structure and influencing factors in high-quality reservoirs with higher gas content will provide the scientific basis for further exploration and exploitation of the Wufeng–Longmaxi Formation deep shale reservoirs in the western Chongqing area. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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14 pages, 25174 KiB  
Article
Analysis of Seismic Response Characteristics of Fractured Carbonate Reservoirs Based on Physical Model (Tarim Basin)
by Li Wei, Bangrang Di and Jianxin Wei
Appl. Sci. 2024, 14(9), 3775; https://doi.org/10.3390/app14093775 - 28 Apr 2024
Cited by 3 | Viewed by 1404
Abstract
Anomalous bright spots, called the string of bead-like response, are typical seismic migration profile features in carbonate fractured reservoirs in the Tarim Basin, and they are indicators of high-quality oil and gas reservoirs. Correctly recognizing the correspondence between fractures and the SBLR can [...] Read more.
Anomalous bright spots, called the string of bead-like response, are typical seismic migration profile features in carbonate fractured reservoirs in the Tarim Basin, and they are indicators of high-quality oil and gas reservoirs. Correctly recognizing the correspondence between fractures and the SBLR can contribute to the efficient drilling of target carbonate fractured reservoirs. Physical models can describe fractured reservoirs more directly and efficiently than real situations and have obvious advantages in accurately and quantitatively designing parameters such as dipping angles and the number of layers of fractured reservoirs. Under such a background, according to the real tectonic characteristics of the Tarim Basin, among the main hydrocarbon reservoirs, fractured reservoirs with various parameters were designed and a physical model was constructed according to the real stratigraphic parameters. After seismic data acquisition and processing, the response characteristics of the string of bead-like response were extracted and summarized from seismic migration profiles for all fractured reservoirs, which provided targeted analyses and discussions on the fracture dipping angle, number of fracture layers, overlying stratigraphic influences, and planar attributes of the fractured reservoirs. In general, the larger the fracture dip, the more difficult it is to identify, while the slope of reflection strength and maximum absolute amplitude attributes can be important markers for fractured reservoir identification. The physical modeling study of fractured reservoirs in this paper can provide a basis for the analysis and prediction of carbonate fractured reservoirs in the Tarim Basin. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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17 pages, 3752 KiB  
Article
Short-Wavelength Infrared Characteristics and Indications of Exploration of the Jiawula Silver–Lead–Zinc Deposit in Inner Mongolia
by Lei Wang, Zian Yang, Weixuan Fang, Dewen Wu, Zhiqiang Liu and Gao Guan
Appl. Sci. 2024, 14(9), 3658; https://doi.org/10.3390/app14093658 - 25 Apr 2024
Viewed by 1137
Abstract
For the Jiawula lead–zinc deposit, as easily accessible resources become depleted, mines are becoming deeper to replenish ore reserves. Identifying large, continuous, and high-grade ore bodies in deep areas has become a daunting problem. Moreover, separating lead–zinc-bearing complex ore bodies from waste material [...] Read more.
For the Jiawula lead–zinc deposit, as easily accessible resources become depleted, mines are becoming deeper to replenish ore reserves. Identifying large, continuous, and high-grade ore bodies in deep areas has become a daunting problem. Moreover, separating lead–zinc-bearing complex ore bodies from waste material and extracting them from associated minerals are also difficult. Thus, pioneering exploratory strategies and technological methodologies are required to make breakthroughs in mineral discovery. Based on extensive-scale structural lithofacies mapping, this paper uses short-wave infrared (SWIR) spectroscopy technology to investigate hydrothermal alteration minerals in the mining area. It has identified a total of 16 hydroxyl-bearing alteration minerals, including chlorite, muscovite, illite, calcite, ankerite, kaolinite, and smectite. These minerals establish zoning characteristics around the ore bodies and on their flanks. They comprise a segmented assemblage that follows the pattern of comb-textured quartz–illite–chlorite–carbonate → muscovite–illite–chlorite–ankerite → illite–smectite–chlorite → chlorite–kaolinite–calcite. Deep-zone illitization with a lower Al–OH absorbance peak wavelength (<2206 nm) and higher crystallinity indices (>1.1) and chloritization with higher Fe–OH absorbance peak wavelengths (>2254) and higher crystallinity indices (>3.0) are indicators of potential hydrothermal centers in the deeper regions. By finding hydrothermal centers and connecting their spatial distribution with existing ore bodies, a pertinent relationship between diabase + andesite, Fe-chlorite + illite, and high-grade mineralization has been established. They correspond well with the lithology-alteration mineralization. This research provides a basis for predicting the positioning of concealed ore bodies deep inside a mine or at the periphery. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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13 pages, 7486 KiB  
Article
Regional Geochemical Characteristics of Lithium in the Mufushan Area, South China
by Peiyu Li, Qingjie Gong, Shaoyu Chen, Peng Li, Jiankang Li, Xuan Wu, Xiaolei Li, Xuefeng Wang and Ningqiang Liu
Appl. Sci. 2024, 14(5), 1978; https://doi.org/10.3390/app14051978 - 28 Feb 2024
Cited by 3 | Viewed by 1348
Abstract
With the explosive growth in demand for lithium (Li) resources, the Mufushan area has been a hotspot for Li deposit exploration in China in recent years. Geochemical maps and geochemical anomaly maps are basic maps in the geochemical exploration of mineral resources. A [...] Read more.
With the explosive growth in demand for lithium (Li) resources, the Mufushan area has been a hotspot for Li deposit exploration in China in recent years. Geochemical maps and geochemical anomaly maps are basic maps in the geochemical exploration of mineral resources. A fixed-value method to contour a Li geochemical map is presented here, in which Li concentrations are divided into 19 levels on 18 fixed values, ranging from 5 μg/g (corresponding to the detection limit) to 1858 μg/g (corresponding to the cut-off grade of Li deposit in hard-rock type) and illustrated in six color tones corresponding to Li areas of low background, high background, low anomaly, high anomaly, mineralization in clay-type, and mineralization in hard-rock type. The geochemical map of Li in the Mufushan area using the new fixed-value method indicates that the study area belongs to the high background area, and the known Li deposits are located in the high anomaly areas. In addition, the geochemical anomaly map of the Mufushan area is drawn using the method of seven levels of classification, and indicates that the known Li deposits are all in the anomaly areas, with anomaly levels not lower than the second level. Furthermore, four other areas are recognized for Li resource potential based on the geochemical map and geochemical anomaly map in the Mufushan area. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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11 pages, 11634 KiB  
Article
Tin (Sn) Geochemical Mapping Based on a Fixed-Value Method: A Case Illustration in Gejiu Area, Southwest China
by Shengchao Xu, Jie Li, Xiaobing Zhang, Zhao Huang, Yuanyou Huang, Yujiang Long, Yongqiang Xu, Xufeng Song, Zheng Chen, Yuanbin Li, Zhaolei Hou and Qingjie Gong
Appl. Sci. 2024, 14(5), 1765; https://doi.org/10.3390/app14051765 - 21 Feb 2024
Cited by 3 | Viewed by 1004
Abstract
Geochemical maps play an important role in mineral resource exploration. There are three traditional methods for creating geochemical maps: the cumulative frequency method, the logarithmic interval method, and the Avg±k∗Std (where Avg and Std are the abbreviations of average and standard deviation, and [...] Read more.
Geochemical maps play an important role in mineral resource exploration. There are three traditional methods for creating geochemical maps: the cumulative frequency method, the logarithmic interval method, and the Avg±k∗Std (where Avg and Std are the abbreviations of average and standard deviation, and k is a multiple of Std) method. However, with the increasing scope of the study area and cumulative data, the limitations of traditional methods, which depend on the amount of data, are exposed. A fixed-value method for Sn geological mapping is proposed to overcome the limitations of traditional methods. In the fixed-value method, Sn concentrations are divided into 19 levels on 18 fixed values ranging from 1 μg/g (corresponding to the detection limit) to 1000 μg/g (corresponding to the cut-off grade of Sn in hard rocks). The 19 levels are mapped in six color tones. The first to fifth levels are the lowest background areas in blue tones, which correspond to Sn concentrations ranging from the minimum to 3.4 μg/g. The sixth to ninth levels are high background areas in yellow tones corresponding to concentrations less than 10 μg/g, the 10th to 12th are low anomaly areas in pink tones less than 28 μg/g, the 13th to 15th are high anomaly areas in red tones less than 200 μg/g (corresponding to the placer cut-off grade), the 16th to 18th in gray tones less than 1000 μg/g, and the 19th level is in black corresponding to Sn ores with Sn concentration not less than 1000 μg/g. The fixed-value method along with three traditional methods was used to contour the Sn geochemical maps in the Gejiu area in Southwest China. The illustration results of the presented fixed-value method and three traditional methods for geochemical mapping of Sn are all feasible for Sn deposit exploration in the Gejiu area, Southwest China. Compared to traditional methods, the presented fixed-value method overcomes the flaws of traditional methods and is also more meaningful in geochemistry. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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18 pages, 3289 KiB  
Article
An Adaptive Weighted Method for Remote Sensing Image Retrieval with Noisy Labels
by Xueqing Tian, Dongyang Hou, Siyuan Wang, Xuanyou Liu and Huaqiao Xing
Appl. Sci. 2024, 14(5), 1756; https://doi.org/10.3390/app14051756 - 21 Feb 2024
Cited by 3 | Viewed by 1523
Abstract
Due to issues with sample quality, there is an increasing interest in deep learning models that can handle noisy labels. Currently, the optimal way to deal with noisy labels is by combining robust active and passive loss functions. However, the weighting parameters for [...] Read more.
Due to issues with sample quality, there is an increasing interest in deep learning models that can handle noisy labels. Currently, the optimal way to deal with noisy labels is by combining robust active and passive loss functions. However, the weighting parameters for these functions are typically determined manually or through a large number of experimental iterations, and even the weighting parameters change as the dataset and the noisy rate change. This can lead to suboptimal results and be time-consuming. Therefore, we propose an adaptively weighted method for the combined active passive loss (APL) in remote sensing image retrieval with noisy labels. First, two metrics are selected to measure the noisy samples: the ratio of the entropy to the standard deviation and the difference of the predicted probabilities. Then, an adaptive weighted learning network with a hidden layer is designed to dynamically learn the weighting parameters. The network takes the above two metrics as inputs and is trained concurrently with the feature extraction network in each batch, without significantly increasing the computational complexity. Extensive experiments demonstrate that our improved APL method outperforms the original manually weighted APL method and other state-of-the-art robust loss methods while saving the time on manual parameter selection. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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37 pages, 11587 KiB  
Article
Application of an Improved A* Algorithm for the Path Analysis of Urban Multi-Type Transportation Systems
by Yan Feng, Weiwei Zhang and Jin Zhu
Appl. Sci. 2023, 13(24), 13090; https://doi.org/10.3390/app132413090 - 7 Dec 2023
Cited by 3 | Viewed by 5385
Abstract
The modern urban transportation service network could be split into unrestricted and restricted networks depending on whether travelers face limitations in route selection. Along with the continuous expansion of the city, it is difficult for travelers to find a more reasonable travel solution [...] Read more.
The modern urban transportation service network could be split into unrestricted and restricted networks depending on whether travelers face limitations in route selection. Along with the continuous expansion of the city, it is difficult for travelers to find a more reasonable travel solution when confronted with such a complex transportation service network, which combines both unrestricted and restricted networks, especially for the park-and-ride (P&R) travel mode. This paper addresses the issue of route analysis in modern urban transportation service systems to provide travelers with reasonable travel solutions based on multiple types of transportation services. An improved A* algorithm is proposed to address the optimal path analysis for restricted networks to provide reasonable travel solutions for public transportation trips. Furthermore, by establishing the topological relationship between restricted and unrestricted networks, this paper presented an improved A* algorithm based on hybrid networks that solves the optimal path analysis problem for P&R trips, bringing convenience to many urban travelers. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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23 pages, 6987 KiB  
Article
Moisture Migration and Recharge Pattern of Low-Permeability Thick Cohesive Soil in Northern Margin of the Jianghan Plain
by Tianwen Liu, Ningtao Wang, Cheng Hu, Qing Wang, Kun Huang, Zhihua Chen and Tingting Shi
Appl. Sci. 2023, 13(23), 12720; https://doi.org/10.3390/app132312720 - 27 Nov 2023
Cited by 1 | Viewed by 1362
Abstract
An extremely low hydraulic conductivity of cohesive soil causes a low transport rate of water and solute, with a time-consuming result, as we all know. Stable isotopes (δD and δ18O) and in situ monitoring systems of the data about soil water, [...] Read more.
An extremely low hydraulic conductivity of cohesive soil causes a low transport rate of water and solute, with a time-consuming result, as we all know. Stable isotopes (δD and δ18O) and in situ monitoring systems of the data about soil water, rainfall, and groundwater were used to analyze the soil moisture migration pattern, using a conceptual model in the field test site, simulated by Hydrus 1D. The results show that multiple rainfalls’ accumulations can cause the water to recharge from soil moisture to micro-confined groundwater, gradually. The soil moisture dynamic change is composed of a dehydration period and absorption period; the cohesive soil water content below 5.0 m was affected by the micro-confined groundwater level and dehydrated in advance due to the level decline. The thick cohesive soil profile can be divided into a shallow mixing zone (0–2 m), steady zone (2–5 m), and deep mixing zone (5–15 m). The effective precipitation recharge was 234 mm and the average infiltration recharge coefficient (Rc) was 0.1389, but the water exchange between the cohesive soil moisture and groundwater was 349 mm in two hydrological years. This paper reveals the moisture migration and recharge pattern of low-permeability thick cohesive soil in a humid area with a micro-confined groundwater aquifer; this is of great significance for groundwater resources evaluation and environmental protection in humid climate plain areas. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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16 pages, 1964 KiB  
Article
Evaluation of Forest Ecological Security and Its Influencing Factors in Multi-Climatic Zones: A Case Study of Yunnan Province
by Zhe Chen, Chunhong Zhang and Syed Turab Raza
Appl. Sci. 2023, 13(22), 12345; https://doi.org/10.3390/app132212345 - 15 Nov 2023
Cited by 3 | Viewed by 2051
Abstract
Forest ecological security is related to national ecological security. Yunnan Province has a significantly stereoscopic climate characterized by diverse and complex vegetation. Therefore, the ecological security of Yunnan Province’s forests, which span multiple climate zones, must be carefully considered. The purpose of this [...] Read more.
Forest ecological security is related to national ecological security. Yunnan Province has a significantly stereoscopic climate characterized by diverse and complex vegetation. Therefore, the ecological security of Yunnan Province’s forests, which span multiple climate zones, must be carefully considered. The purpose of this study is to evaluate the forest ecological security situation and influencing factors in Yunnan Province in 2017. Utilizing data from remote sensing, the Yunnan Province Yearbooks, socioeconomic statistical data, and better pressure-state-response modeling, this work produced an index system containing state and societal pressure. The evaluation indicators were weighted using a combination of entropy weighting and expert weighting, using 16 prefectures in Yunnan Province as samples. Using the fuzzy matter-element technique, the forest ecological security situation in Yunnan Province in 2017 was assessed, and the contributing causes were examined. Results indicate that there are spatial distribution differences in ecological security in various regions of Yunnan Province. The regions with the greatest indices of forest ecological security were found in Xishuangbanna in the south and Nujiang and Diqing in the northwest of Yunnan Province, while those areas with the lowest indices were distributed in Qujing and Zhaotong in the northeast and Baoshan in the west. Results of the grey relation analysis show that those factors that influence forest ecological security across different prefectures showed significant diversity. In Yunnan Province, the main influencing factors include days when the air quality reaches Level 2 or higher, the percentage of natural forest acreage and accumulation, the value of forest ecological service function per unit area, the annual average temperature, and forest coverage. The influence of the forest status index was greater than that of the forest pressure index. The findings of this work can guide decisions related to regional forest ecological security construction across multiple climate zones. In view of the differences in ecological security status and influencing factors in different regions, ecological environment governance should be adapted to local conditions to ensure the coordinated development of nature, the economy, and the ecological environment. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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21 pages, 5154 KiB  
Article
An Elastic-Window-Based Method for the Underdetermined Problem in Linear Spectral Unmixing to Enhance the Spatial Resolution of the Normalized Difference Vegetation Index Time Series
by Boyu Liu and Yushuo Zhang
Appl. Sci. 2023, 13(22), 12171; https://doi.org/10.3390/app132212171 - 9 Nov 2023
Viewed by 1245
Abstract
Inverting land cover reflectance or derived indices from low-spatial-resolution images to refine the spatial resolution of this data is cost-effective for land surface monitoring applications that face technical or budget limitations. Based on the linear spectral mixing model, many approaches have successfully unmixed [...] Read more.
Inverting land cover reflectance or derived indices from low-spatial-resolution images to refine the spatial resolution of this data is cost-effective for land surface monitoring applications that face technical or budget limitations. Based on the linear spectral mixing model, many approaches have successfully unmixed coarse mixed pixels using high-spatial-resolution land cover maps in the past decades. However, in some cases, the solutions of linear systems composed of several mixed pixels may not be acquired due to the underdetermined problem. This study presents the causes of this problem and proposes an iterative approximation strategy to address it. An elastic-window-based algorithm was developed, where the initial size of the window was calculated based on the land cover of the mixed pixel. Mixed pixels of neighborhoods with similar land covers were then selected to form the unmixing linear system, which was examined through a simulation test to ensure it was not underdetermined. Otherwise, the window would expand to include more adjacent pixels. This process was repeated until a successful solution was obtained. A statistical analysis of sixty land cover maps from around the globe shows that the underdetermined problem exists at a low level but becomes more serious with an increase in mixed scale. The results demonstrate that the proposed algorithm effectively prevents the underdetermined problem for mixed pixels of different scales and can be integrated into the coarse NDVI downscaling procedure to refine spatial resolution. This study provides a reference for estimating underdetermined mixed pixels and benefits applications that require dealing with the inversion of land cover values directly. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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17 pages, 5416 KiB  
Article
Heat-Flow Coupling Law for Freezing a Pipe Reinforcement with Varying Curvatures
by Kun Yang, Jun Hu and Tao Wang
Appl. Sci. 2023, 13(19), 10932; https://doi.org/10.3390/app131910932 - 2 Oct 2023
Viewed by 1445
Abstract
Using the temperature and seepage field-coupling module within COMSOL Multiphysics software, we examined freezing behavior and its evolving patterns in curved underground freezing pipes. This study employed transient states, with the Darcy’s law and porous-media heat-transfer options activated in the Physical Field Interface [...] Read more.
Using the temperature and seepage field-coupling module within COMSOL Multiphysics software, we examined freezing behavior and its evolving patterns in curved underground freezing pipes. This study employed transient states, with the Darcy’s law and porous-media heat-transfer options activated in the Physical Field Interface of the Physical Field and Variable Selection column. The models were created to establish numerical models of freezing reinforcement for both single and multiple pipes with various curvatures. These models were designed to simulate the evolving temperature and seepage fields of soil under diverse freezing conditions. Subsequently, this research utilized the models to simulate the freezing and consolidation conditions of a shallowly buried tunnel within the context of shallow tunnel conditions. The study reveals that after freezing a single pipe using water flow, the change in thickness of the frozen wall in curved pipes is notably smaller than that in straight pipes. This difference is particularly pronounced in the upstream section. Specifically, at a distance of −2000 mm from the main surface, the change in thickness of the frozen wall in straight pipes exceeds that in s = 7 curved pipes by approximately 350 mm. The smaller the long arc ratio s, the greater the arc of the freezing tube and the better the water-blocking effect. In the multi-pipe freezing model, the s = 7 curved pipes exhibit a frozen-wall thickness approximately 120 mm greater than that of straight pipes at a distance of −2000 mm from the main surface. Under the condition of a shallow buried concealed excavation with surging water, a pipe with a long arc ratio s = 7 arc freezing at 46 d attains a permafrost curtain thickness that is equivalent to that achieved by the straight pipe freezing at 58 d. This reduction in thickness shortens the working period by 12 days, resulting in a more efficient process. The successful application of the freezing method in the water-rich aquifer is expected to be a valuable reference for similar projects in the future. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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18 pages, 12807 KiB  
Article
Environmental Risk Source Analysis and Classification of Zones: Subway Construction
by Yangchun Yuan, Yongjun Qin, Yongkang Zhang, Liangfu Xie, Xin Meng and Zheyi Guo
Appl. Sci. 2023, 13(10), 5831; https://doi.org/10.3390/app13105831 - 9 May 2023
Cited by 4 | Viewed by 1987
Abstract
Examining the environmental risk sources of regional subway construction is crucial for ensuring construction safety and providing guidance for future subway line planning. This study focused on Urumqi’s main urban area and used SBAS-InSAR analysis technology to extract the settlement rate field within [...] Read more.
Examining the environmental risk sources of regional subway construction is crucial for ensuring construction safety and providing guidance for future subway line planning. This study focused on Urumqi’s main urban area and used SBAS-InSAR analysis technology to extract the settlement rate field within 600 m of Urumqi Metro Line 1 and investigate these risk sources. Results showed that the environmental risk sources affecting subway construction in the study area could be classified into four categories: geological conditions, distribution of high-rise buildings, density of road networks, and density of clustered buildings. The study further analyzed the spatial distribution of each risk source and developed a comprehensive impact zoning evaluation model for environmental risk sources in the study area. The model was then used to assess the risk of the currently planned subway lines (1–7), revealing that the largest area of subway construction environmental risk sources (1444 partitions) was associated with soil layer, IV high-rise building risk, IV road network risk, and IV building density risk. Additionally, the study found that environmental risk sources had the most significant impact on Metro Line 6, emphasizing the importance of closely monitoring risk factors during future construction. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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17 pages, 3033 KiB  
Article
Study on the Thermospheric Density Distribution Pattern during Geomagnetic Activity
by Lirong Yin, Lei Wang, Lijun Ge, Jiawei Tian, Zhengtong Yin, Mingzhe Liu and Wenfeng Zheng
Appl. Sci. 2023, 13(9), 5564; https://doi.org/10.3390/app13095564 - 30 Apr 2023
Cited by 49 | Viewed by 3130
Abstract
The atmospheric density of the thermosphere is a fundamental parameter for spacecraft launch and orbit control. Under magnetic storm conditions, the thermospheric atmospheric density experiences significant fluctuations, which have a negative impact on spacecraft control. Exploring thermospheric density during geomagnetic storms can help [...] Read more.
The atmospheric density of the thermosphere is a fundamental parameter for spacecraft launch and orbit control. Under magnetic storm conditions, the thermospheric atmospheric density experiences significant fluctuations, which have a negative impact on spacecraft control. Exploring thermospheric density during geomagnetic storms can help to mitigate the effects of such events. Research on the inversion of accelerometer measurements for different satellites and the variations of atmospheric density under extreme conditions is still in its infancy. In this paper, the distribution of atmospheric density during three geomagnetic storms is investigated from the inversion results of the Swarm-C accelerometer. Three major geomagnetic storms and their recovery phases are selected as case studies. The thermospheric density obtained by Swarm-C is separated into day and night regions. The empirical orthogonal function analysis method is used to study the spatiotemporal distribution of thermospheric density during geomagnetic storms. The results indicate that storms have a more significant impact on nighttime thermospheric density. The impact of magnetic storms on the temporal distribution of thermospheric density is considerable. The first-order empirical orthogonal function (EOF) time coefficient value on the day after the storm is the largest, reaching 2–3 times that before the magnetic storm. The impact of magnetic storms on atmospheric density is mainly reflected in the time distribution. The spatial distribution of atmospheric density is less affected by magnetic storms and is relatively stable in the short term. The impact of magnetic storms on the spatial distribution of nighttime thermospheric density is more significant than that of daytime regions, and the response of daytime regions to magnetic storms is slower. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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13 pages, 2881 KiB  
Article
Utilizing Multilevel Modeling to Measure Neighborhood Dynamics and Their Impact on House Prices
by Baoyun Guo, Kenan Li and Cong Fu
Appl. Sci. 2023, 13(8), 5180; https://doi.org/10.3390/app13085180 - 21 Apr 2023
Cited by 1 | Viewed by 1724
Abstract
For decades, researchers have been concerned with house price modeling, and recognition has grown for the necessity of considering environmental and contextual variables in the process. This research examines the association between neighborhood characteristics and all individual house sale prices in Lucas County, [...] Read more.
For decades, researchers have been concerned with house price modeling, and recognition has grown for the necessity of considering environmental and contextual variables in the process. This research examines the association between neighborhood characteristics and all individual house sale prices in Lucas County, Ohio, from 2012 to 2016, through a multilevel modeling (MLM) approach. Although there are various ways to define neighborhoods, census tracts and school districts are used in this study. Neighborhood characteristics include a foreclosure score, race heterogeneity, median household income, and built environment variables, such as walkability indexes. School district characteristics include student performance, tuition expenditures per pupil, and percent of expenditures spent on classroom instruction. The advantage of the multilevel model, is that it allows us to derive reliable estimates of place differences, representing a considerable improvement over the single-level model. Significant correlations were identified between house prices and foreclosure score, student performance, and tuition expenditures per pupil. The MLM results indicate that house prices not only lay in house characteristics themselves but also in neighborhood features, thus MLM offers good prediction accuracy and high explanatory power. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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15 pages, 3623 KiB  
Article
Multi-Mode Imaging of Ambient Background Noise for Karst Detection in the Limestone Area Based on Frequency-Bessel Transform
by Song Chen, Daohan Liu, Fei Cheng and Junjie Xu
Appl. Sci. 2023, 13(8), 5135; https://doi.org/10.3390/app13085135 - 20 Apr 2023
Cited by 1 | Viewed by 1855
Abstract
In response to the challenges of karst geophysical exploration in an environment with strong external interference, this paper proposes a new method, namely the frequency-Bessel transform method, for extracting multi-order dispersion curves of surface waves from background noise to characterize karst. The observation [...] Read more.
In response to the challenges of karst geophysical exploration in an environment with strong external interference, this paper proposes a new method, namely the frequency-Bessel transform method, for extracting multi-order dispersion curves of surface waves from background noise to characterize karst. The observation noise data of the Wuhan karst development area are used as an example, where the dolomitic limestone and limestone mixed with dolomite of the Jialing River Formation of the middle lower Triassic are widely developed in the observation area. The frequency-Bessel transform method involves performing a Bessel integral transformation on the cross-correlation coefficient of background noise in the frequency domain. Firstly, by synthesizing theoretical noise data and comparing it with the spatial autocorrelation method—which is currently the main method for extracting the fundamental dispersion curve of surface waves—it is verified that the frequency-Bessel transform method can extract the higher-mode dispersion curve. Then, by taking the actual measured single-point noise data as an example, the effect of applying the frequency-Bessel transform to the actual noise data is tested, and the inversion of the fine structure of the strata by the addition of higher-mode dispersion, the use of the damped least squares inversion method, and the joint inversion of fundamental and higher-mode dispersion curves are analyzed. The higher-mode dispersion curve of Rayleigh surface wave extracted by the frequency-Bessel transform is much clearer, and the 2D shear wave velocity structure profile obtained from inversion explains the karst development area, karst strip area, and thickness of the Quaternary overburden. The inferred results match with the actual borehole data. Multi-mode imaging of background noise based on the frequency-Bessel method can be applied to depict karst in complex backgrounds, and has significant potentiality in the field of ambient seismic noise tomography, providing a new idea and method for karst detection in near-surface engineering. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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19 pages, 4938 KiB  
Article
Seismic Interferometry Method Based on Hierarchical Frequency Fusion and Its Application in Microtremor Survey
by Xingang Mou, Xingyuan Wan, Hongyue Liu, Jinhuo Zheng, Xiao Zhou and Bin Zhou
Appl. Sci. 2023, 13(8), 4840; https://doi.org/10.3390/app13084840 - 12 Apr 2023
Viewed by 1509
Abstract
Site velocity structure determination and stratigraphic division are important purposes of microtremor survey, and the precision of dispersion curves is an important factor affecting the accuracy of microtremor survey. In order to obtain more accurate dispersion curve and S-wave velocity structure, this paper [...] Read more.
Site velocity structure determination and stratigraphic division are important purposes of microtremor survey, and the precision of dispersion curves is an important factor affecting the accuracy of microtremor survey. In order to obtain more accurate dispersion curve and S-wave velocity structure, this paper proposed a dispersion curve processing method based on hierarchical frequency fusion of seismic interferometry. Analysis was performed on the link between station pair spacing and frequency component of the collected microtremor signal dependability and exploration depth. A mathematical model of station distances and reliable frequencies of the dispersion curves were achieved through a hierarchical relationship between station distances. Then, a fusion criterion was proposed to determine the fusion boundary based on the reliable frequency, and the dispersion curves of station pairs with different distances were fused to obtain the final dispersion curve. Finally, a more accurate velocity structure was obtained through s-wave velocity conversion from shallow layers to deep ones. The method was applied to the microtremor survey of the proposed high-rise building site in Xiamen. The rectangular observation array was arranged, and the dispersion curves were extracted and processed using hierarchical frequency fusion and traditional superimposed averaging method, and the S-wave velocity and stratigraphic structure were obtained. The experimental results show that the S-wave velocity and stratigraphic structure obtained using the hierarchical frequency fusion method are in better agreement with the borehole results than the superimposed averaging method, which shows its effectiveness and application prospect. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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19 pages, 5031 KiB  
Article
Method for the Construction of Urban Road Digital Elevation Models Integrated with Semantic Information
by Mingwei Zhao and Na Zhao
Appl. Sci. 2023, 13(7), 4210; https://doi.org/10.3390/app13074210 - 26 Mar 2023
Cited by 4 | Viewed by 2344
Abstract
Roads are a type of typical artificial terrain, and are key components of urban terrain. Road networks formed by connections between different roads not only form the skeleton of urban terrain, but also plays an important role in transmitting energy and matter on [...] Read more.
Roads are a type of typical artificial terrain, and are key components of urban terrain. Road networks formed by connections between different roads not only form the skeleton of urban terrain, but also plays an important role in transmitting energy and matter on the urban surface. Therefore, how to consider characteristics when constructing the digital road elevation model (DEM) has become an important research topic in the field of geographic information and mapping. Using high-definition unmanned aerial vehicle (UAV) images as the basic data source, this study proposes a new method for constructing the road DEM by analyzing semantic features such as road shape and function. This method first takes the sideline and centerline of the road as the macroscopic undulation morphological constraints. It uses the shape control equation of the local domain to constrain the morphological change characteristics of the road surface in the transverse and longitudinal directions, in order to construct the road DEM with high fidelity to the surface shape characteristics. Then, in terms of the water catchment function of the road surface, a road DEM correction method considering surface flow direction characteristics is designed to ensure that the water catchment path of the road surface conforms to the actual situation. For this paper, several typical roads in Chuzhou University in Anhui Province, China, were selected as the experimental objects to carry out a DEM construction experiment. The results indicate the following: (1) compared with the traditional construction method, the DEM shape of the road constructed by this research method is more consistent with the actual road shape, and the smoothness of the road surface is better; (2) due to the high density and high elevation accuracy of the point cloud used in modeling, the elevation adjustment strategy of the sideline and centerline of the road implemented in this study does not reduce elevation accuracy, indicating that an adjustment to the elevation information is necessary for constructing the DEM of special artificial terrain; and (3) the DEM correction method proposed in this paper to find the correct catchment path can ensure that the processed DEM can accurately simulate the surface catchment process, and the correction of the elevation of the road DEM is also controlled within a small range without affecting the elevation accuracy of the regional DEM. This study has reference value for implementing projects such as urban terrain expression in the construction of 3D China. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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15 pages, 2919 KiB  
Article
Automatic Extraction of Flooding Control Knowledge from Rich Literature Texts Using Deep Learning
by Min Zhang and Juanle Wang
Appl. Sci. 2023, 13(4), 2115; https://doi.org/10.3390/app13042115 - 7 Feb 2023
Cited by 4 | Viewed by 2053
Abstract
Flood control is a global problem; increasing number of flooding disasters occur annually induced by global climate change and extreme weather events. Flood studies are important knowledge sources for flood risk reduction and have been recorded in the academic literature. The main objective [...] Read more.
Flood control is a global problem; increasing number of flooding disasters occur annually induced by global climate change and extreme weather events. Flood studies are important knowledge sources for flood risk reduction and have been recorded in the academic literature. The main objective of this paper was to acquire flood control knowledge from long-tail data of the literature by using deep learning techniques. Screening was conducted to obtain 4742 flood-related academic documents from past two decades. Machine learning was conducted to parse the documents, and 347 sample data points from different years were collected for sentence segmentation (approximately 61,000 sentences) and manual annotation. Traditional machine learning (NB, LR, SVM, and RF) and artificial neural network-based deep learning algorithms (Bert, Bert-CNN, Bert-RNN, and ERNIE) were implemented for model training, and complete sentence-level knowledge extraction was conducted in batches. The results revealed that artificial neural network-based deep learning methods exhibit better performance than traditional machine learning methods in terms of accuracy, but their training time is much longer. Based on comprehensive feature extraction capability and computational efficiency, the performances of deep learning methods were ranked as: ERNIE > Bert-CNN > Bert > Bert-RNN. When using Bert as the benchmark model, several deformation models showed applicable characteristics. Bert, Bert-CNN, and Bert-RNN were good at acquiring global features, local features, and processing variable-length inputs, respectively. ERNIE showed improved masking mechanism and corpus and therefore exhibited better performance. Finally, 124,196 usage method and 8935 quotation method sentences were obtained in batches. The proportions of method sentence in the literature showed increasing trends over the last 20 years. Thus, as literature with more method sentences accumulates, this study lays a foundation for knowledge extraction in the future. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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14 pages, 4521 KiB  
Article
Three-Dimensional Numerical Modeling of Artificially Freezing Ground in Metro Station Construction
by Bo Wang, Jun Hu, Xiaoqi Lin and Hui Zeng
Appl. Sci. 2023, 13(1), 671; https://doi.org/10.3390/app13010671 - 3 Jan 2023
Cited by 2 | Viewed by 2435
Abstract
In this study, the engineering background of No. 2 complex connecting passage of Binhu Road Station/Jinhu Square Station of Nanning Metro Line 3 is investigated, where the artificial ground freezing technique is adopted. A three-dimensional finite element model is established to investigate the [...] Read more.
In this study, the engineering background of No. 2 complex connecting passage of Binhu Road Station/Jinhu Square Station of Nanning Metro Line 3 is investigated, where the artificial ground freezing technique is adopted. A three-dimensional finite element model is established to investigate the temperature development of the frozen soil curtain, with a simulation of the dynamic evolution of the frosted soil curtain. The finite element model is validated by comparing the overall trend of the measured temperature value and the resulting temperature value, which are roughly the same. According to the design scheme, the weakest part of the whole frozen soil curtain is the top of the bell mouth where the downhole tunnel intersects the connecting passage. It is recommended to make a row of smaller freezing holes to enhance the freezing effect in this area. The thickness of the frozen soil curtain reached 1.75 m or more, indicating that the whole frozen soil curtain meets the design requirements and shows the right features for excavation construction. After freezing for 40 days, the average thickness of the frozen soil curtain is 2.4 m, indicating that the freezing effect meets the design requirements. The project can be successfully carried out, which suggests that the underneath passage construction is feasible. As a result, the results of the numerical model are applicable for comparable projects using artificially freezing ground in metro station construction. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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15 pages, 4609 KiB  
Article
Estimation of Shallow Shear Velocity Structure in a Site with Weak Interlayer Based on Microtremor Array
by Cong Jin, Song Lin, Jing Wang, Hongwei Zhou and Miao Cheng
Appl. Sci. 2023, 13(1), 185; https://doi.org/10.3390/app13010185 - 23 Dec 2022
Cited by 1 | Viewed by 1524
Abstract
A site condition survey is extremely important for the seismic fortification of major projects. The distribution of underlying weak interlayer in sites is extremely harmful to buildings. However, it is a technical problem to find out the distribution of weak interlayer in the [...] Read more.
A site condition survey is extremely important for the seismic fortification of major projects. The distribution of underlying weak interlayer in sites is extremely harmful to buildings. However, it is a technical problem to find out the distribution of weak interlayer in the overburden. The shallow velocity structure can directly reflect the change characteristics of a stratigraphic structure. In this paper, acquisition of background noise is conducted using a microtremor linear array method, and the distribution characteristics of two typical stratigraphic structures in Wuhan, Hubei Province, are obtained through an inversion of the apparent S-wave velocity; meanwhile, the equivalent shear-wave velocity and the overburden thickness are estimated, which provides a basis for site classification. The research results are as follows: (1) The two-dimensional profile of the apparent S-wave velocity obtained by the microtremor linear array method can be used for fine imaging of the stratum with weak interlayer, and its distribution form and velocity structure characteristics are highly consistent with those of the drilling data. (2) Compared to the borehole data obtained through in situ test, the error of the overburden thickness and the equivalent shear-wave velocity estimated by the inversion of the apparent S-wave velocity is only about 10%, and the estimated parameters can be directly used for site classification. These results can provide important parameters for seismic fortification of major projects, and also provide reference for the exploration of unfavorable geological bodies, such as weak interlayer in complex urban areas, in the future, which can have good scientific significance and popularization value. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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20 pages, 8848 KiB  
Article
Optimization Approaches of Multi-Dimensional Environments in Rural Space Reproduction Driven by Tourism
by Yingxing Chen, Qing Zhang, Difei Zhao, Sotiris Folinas and Wei Zhang
Appl. Sci. 2022, 12(24), 12527; https://doi.org/10.3390/app122412527 - 7 Dec 2022
Cited by 5 | Viewed by 2542
Abstract
Rural tourism is an important driving force for the transformation of rural society in the process of urbanization. However, besides promoting rural economy, it also interrupts the development of the rural living, human, manage and economic multi-dimensional environments. Space reconstruction in rural settlements [...] Read more.
Rural tourism is an important driving force for the transformation of rural society in the process of urbanization. However, besides promoting rural economy, it also interrupts the development of the rural living, human, manage and economic multi-dimensional environments. Space reconstruction in rural settlements is an important means to optimize multi-dimensional environments and revitalize rural tourism. Focusing on two types of rural settlements, namely the “relocation village” and the “sightseeing and settlement symbiosis village”, this study has revealed the affecting mechanism of space reconstruction in rural tourist locations on the local multi-dimensional environment by establishing a multi-dimensional environment evaluation system through an analytic, hierarchical process. Subsequently, based on the theoretical perspective of the reproduction of the space and the paradigm of the three-fold model, a comprehensive optimization path of rural multi-dimensional environments has been proposed. The results show that in the space reconstruction process driven by tourism: (1) the multi-dimensional environments of the “sightseeing and settlement symbiosis village” generally develop better than the “relocation village”; (2) the ecological environment is the direct benefit while the management environment and economic environment are the bottlenecks; (3) the “sightseeing and settlement symbiosis village” is more appealing to tourists who are interested in rural tourism since it keeps more rustic characteristics than the “relocation village”; (4) in order to optimize the multi-dimensional environments, “relocation village” should pay more attention to the space needs of residents, improve space utilization rates, and increase the residents’ sense of belonging; (5) “sightseeing and settlement symbiosis village” needs to resolve the contradiction between the tourism and living demands, improve the reproduction process driven by diversified entities, and reconstruct the neighborhood network under rural tourism. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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17 pages, 4355 KiB  
Article
Research on the Symbolic 3D Route Scene Expression Method Based on the Importance of Objects
by Fulin Han, Liang Huo, Tao Shen, Xiaoyong Zhang, Tianjia Zhang and Na Ma
Appl. Sci. 2022, 12(20), 10532; https://doi.org/10.3390/app122010532 - 19 Oct 2022
Cited by 1 | Viewed by 1631
Abstract
In the study of 3D route scene construction, the expression of key targets needs to be highlighted. This is because compared with the 3D model, the abstract 3D symbols can reflect the number and spatial distribution characteristics of entities more intuitively. Therefore, this [...] Read more.
In the study of 3D route scene construction, the expression of key targets needs to be highlighted. This is because compared with the 3D model, the abstract 3D symbols can reflect the number and spatial distribution characteristics of entities more intuitively. Therefore, this research proposes a symbolic 3D route scene representation method based on the importance of the object. The method takes the object importance evaluation model as the theoretical basis, calculates the spatial importance of the same type of objects according to the spatial characteristics of the geographical objects in the 3D route scene, and constructs the object importance evaluation model by combining semantic factors. The 3D symbols are then designed in a hierarchical manner on the basis of the results of the object importance evaluation and the CityGML standard. Finally, the LOD0-LOD4 symbolic 3D railway scene was constructed on the basis of a railroad data to realise the multi-scale expression of symbolic 3D route scene. Compared with the conventional loading method, the real-time frame rate of the scene was improved by 20 fps and was more stable. The scene loading speed was also improved by 5–10 s. The results show that the method can effectively improve the efficiency of the 3D route scene construction and the prominent expression effect of the key objects in the 3D route scene. Full article
(This article belongs to the Special Issue State-of-the-Art Earth Sciences and Geography in China)
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