Advanced Materials and Technologies in Deep Rock Engineering

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Energies energies	3.2	7.3	2008	16.2 Days	CHF 2600
Materials materials	3.2	6.4	2008	15.2 Days	CHF 2600
Minerals minerals	2.2	4.4	2011	18.2 Days	CHF 2400
Processes processes	2.8	5.5	2013	16 Days	CHF 2400
Sustainability sustainability	3.3	7.7	2009	19.3 Days	CHF 2400

21 pages, 11536 KB

Open AccessArticle

A New Hydro-Mechanical Coupling Numerical Model for Predicting Water Inflow in Karst Tunnels Considering Deformable Fracture

by Guodong Li, Changlong Li, Jianxing Liao and Hong Wang

Sustainability 2023, 15(20), 14703; https://doi.org/10.3390/su152014703 - 10 Oct 2023

Cited by 3 | Viewed by 1588

Abstract

The accurate prediction of groundwater inflow in tunnels in karst regions has been a difficult problem to overcome for a long time. This study proposes an equivalent fracture model that takes into account unsaturated seepage and fracture deformation to predict tunnel water inflow, [...] Read more.

The accurate prediction of groundwater inflow in tunnels in karst regions has been a difficult problem to overcome for a long time. This study proposes an equivalent fracture model that takes into account unsaturated seepage and fracture deformation to predict tunnel water inflow, which is constructed based on the TOUGH-FLAC3D framework. The proposed model with complete failure mechanisms of fracture, including shear failure and tensile failure, was applied to predict the water inflow of the Jianxing Tunnel in Guizhou Province to verify its effectiveness. The results indicate that the proposed numerical model was found to be comparable to on-site observations in predicting inflow rate. The inflow rate in a fractured network reaches a steady state faster than that in a non-fractured network. There is a significant difference of 100 times between the highest transient rate and the stable rate between the fracture network and the non-fractured model. The excavation-induced stress redistribution resulted in slip fracture occurring within a distance of approximately 8.2 m from the tunnel wall, which can increase the fracture width and in turn increases the amount of water flowing into the tunnel by about 50%. In addition, this paper also analyzes the impact of the factors of fracture density, incline angle, stress anisotropy, and initial fracture width on the inflow rate during tunnel construction. The study emphasizes the significance of considering deformable fractures and provides valuable insights for improving numerical tools for inflow prediction during tunnel construction. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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22 pages, 8492 KB

Open AccessArticle

Effects of Confining Stress on Blast-Induced Damage Distribution of Rock with Discontinuity

by Rongjian Pan, Peiyu Wang, Zilong Zhou, Riyan Lan, Lu Chen, Hongquan Yang, Cuigang Chen, Jinkun Zhang and Yang Liu

Sustainability 2023, 15(17), 13278; https://doi.org/10.3390/su151713278 - 4 Sep 2023

Cited by 1 | Viewed by 2110

Abstract

Discontinuous rock mass, such as joints and fractures, have a great influence on the blasting quality and sometimes induce additional damage at the discontinuity. In deep rock engineering, high in situ stress makes the damage mechanism of rock with discontinuity under blasting loading [...] Read more.

Discontinuous rock mass, such as joints and fractures, have a great influence on the blasting quality and sometimes induce additional damage at the discontinuity. In deep rock engineering, high in situ stress makes the damage mechanism of rock with discontinuity under blasting loading more complicated. Quantitative analysis of blast-induced damage in discontinuous rock under high in situ stress is of great importance in guiding the fine blast design. In this paper, a series of numerical models have been established to quantitatively investigate the effect of confining stress and inclination angle on blast-induced damage of rock with discontinuity. The numerical results show that the discontinuity obviously changes the distribution mode of blast-induced damage, and there is more damage near the discontinuity. The blast-induced damage crack length of discontinuous rock decreases as hydrostatic stress rises. Under non-hydrostatic stress, the damage crack propagation appears to have a higher tendency in the higher confining stress direction. In addition, the inclination angle of discontinuity will affect the damage distribution of rock with discontinuity. The fragmentation degree is greatest when the discontinuity is perpendicular to the direction of higher confining stress. Due to the presence of discontinuity, the guiding effect of higher confining stress on damaged cracks is weakened. The results provide a reference for the tunnel fine-blasting design of rock with discontinuity. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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17 pages, 7794 KB

Open AccessArticle

Study on the Corrosion Behavior of Cemented Organic Soil in Dianchi Lake, China

by Wenlian Liu, Jing Cao, Yunfei Song, Sugang Sui, Hanhua Xu, Yongfa Guo, Wenyun Ding and Siyang Huang

Materials 2023, 16(17), 5951; https://doi.org/10.3390/ma16175951 - 30 Aug 2023

Cited by 3 | Viewed by 1429

Abstract

To study the corrosion behavior of cement soil in peat soil, the experiment involves the preparation of peat soil by incorporating humic acid into cohesive soil with a lower organic matter content. Cement soil samples are then prepared by adding cement to the [...] Read more.

To study the corrosion behavior of cement soil in peat soil, the experiment involves the preparation of peat soil by incorporating humic acid into cohesive soil with a lower organic matter content. Cement soil samples are then prepared by adding cement to the mixture. These samples are subjected to immersion in fulvic acid solution and deionized water to simulate different working environments of cement soil. The experiment considers immersion time as the variable factor. It conducts observations of apparent phenomena, ion leaching tests, and unconfined compression strength tests on the cement soil. The experiment results are as follows: (1) With increasing immersion time, the surface of the cement soil in the peat soil environment experiences the disappearance of Ca(OH)₂ and calcium aluminate hydrate. Additionally, large amounts of bird dropping crystals precipitate on the surface and within the specimen. The cement soil undergoes localized disintegration due to extensive erosion caused by swelling forces. (2) In the peat soil environment, fulvic acid reacts with the hydration products of cement, resulting in partial leaching of ions such as Ca²⁺, Mg²⁺, Al³⁺, and Fe³⁺ into the immersion solution. The lower the pH of the fulvic acid immersion (indicating higher concentration), the more significant the ion leaching. Increasing the ratio of humic acid to cement can slow down the leaching of ions. The cement soil undergoes dissolutive erosion in the peat soil environment. (3) The peat soil environment exerts both strengthening and corrosive effects on the cement soil. Cement soil without humic acid exhibits noticeable corrosion in the peat soil environment, gradually decreasing strength as immersion time increases. The strength decreases by 83% from 28 to 365 days. In contrast, cement soil with humic acid experiences an initial period of strengthening, leading to a significant increase in strength in the short term (34% increase from 28 to 90 days). However, the corrosive effects gradually dominate, resulting in a decrease in strength over time. The strength decreases by 80% from 90 to 365 days. This study also explores the strengthening effects of peat soil on cement soil. It identifies phenomena such as extensive erosion and new substance precipitation in cement soil. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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9 pages, 9933 KB

Open AccessArticle

Application of AFM on Identifying Mechanical Properties of Individual Minerals and Surface Properties of Crack with High Resolution in Shale

by Shizhong Cheng, Mao Sheng and Peng Xu

Processes 2023, 11(8), 2498; https://doi.org/10.3390/pr11082498 - 19 Aug 2023

Cited by 1 | Viewed by 2255

Abstract

Improving the resolution and accuracy of the mechanical properties of organic-rich shale is very important. The results can reveal the mechanical properties of shale from micro scale and serve as a guide for the design of hydraulic fracture optimization parameters. This study introduced [...] Read more.

Improving the resolution and accuracy of the mechanical properties of organic-rich shale is very important. The results can reveal the mechanical properties of shale from micro scale and serve as a guide for the design of hydraulic fracture optimization parameters. This study introduced an advanced technique to obtain the mechanical properties of shale with high resolution (58.6 nm/pixel) by combining SEM, EDS, and Atomic Force Microscopy (AFM). To locate the target area in SEM and AFM accurately, a positioning technique that uses special distributions of pyrite was established. AFM PeakForce QNM mode was selected due to its advantages at capturing topography and mechanical properties in material. Results illustrated the ability of AFM to obtain the mechanical properties (modulus) of individual mineral components in shale, the detailed topography of crack, and mechanical properties of minerals in a specific area. In particular, the mechanical properties of minerals around crack explained the layered distribution of minerals around the fractures, and the cracks developed in the clay mineral layer was detected. This article demonstrates the great potential application of AFM in shale. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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19 pages, 13087 KB

Open AccessArticle

Energy Dissipation of Hydraulic Support Columns under Rockfall Impact Load in Steeply Dipping Coal Seams

by Ming Liu, Bohao Luan and Yang Xiao

Processes 2023, 11(8), 2497; https://doi.org/10.3390/pr11082497 - 19 Aug 2023

Cited by 2 | Viewed by 1299

Abstract

Rockfall disasters have long restricted the further improvement of the safety level of steeply dipping coal seams (SDCSs). When a rockfall disaster occurs, it causes damage to the hydraulic support and other equipment at the working face. An effective way to carry out [...] Read more.

Rockfall disasters have long restricted the further improvement of the safety level of steeply dipping coal seams (SDCSs). When a rockfall disaster occurs, it causes damage to the hydraulic support and other equipment at the working face. An effective way to carry out protection design is using the law of rockfall migration and energy evolution. Therefore, this study used the polyhedral rockfall migration and its impact process on the hydraulic support equipment of the working face as the research object and analyzed the influence of relevant parameters on the maximum contact deformation, maximum impact force, and energy absorption of the column during the collision and contact between the rockfall and the hydraulic support column. Firstly, with hexahedral rockfall as an example, the migration process of rockfall was simulated using PFC3D software. Secondly, according to the Hertz contact theory, the contact model of the shock process between the rockfall and the hydraulic support column was constructed, and the maximum deformation and maximum impact force of the collision contact between the rockfall and the column were obtained. Finally, the Hamilton principle and the Galerkin discrete method were used to construct the dynamic model of the collision between the rockfall and the column, and the energy evolution law of the shock process between the rockfall and the column was studied. The conclusions of this paper can provide a certain theoretical basis for the prediction of rockfall disasters and the design of rockfall protection devices. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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14 pages, 3302 KB

Open AccessArticle

Triaxial Compression Strength Prediction of Fissured Rocks in Deep-Buried Coal Mines Based on an Improved Back Propagation Neural Network Model

by Yiyang Wang, Bin Tang, Wenbin Tao, Anying Yuan, Tianguo Li, Zhenyu Liu, Fenglin Zhang and An Mao

Processes 2023, 11(8), 2414; https://doi.org/10.3390/pr11082414 - 10 Aug 2023

Cited by 5 | Viewed by 1743

Abstract

In deep coal mine strata, characterized by high ground stress and extensive fracturing, predicting the strength of fractured rock masses is crucial for stability analysis of the surrounding rock in coal mine strata. In this study, rock samples were obtained from construction sites [...] Read more.

In deep coal mine strata, characterized by high ground stress and extensive fracturing, predicting the strength of fractured rock masses is crucial for stability analysis of the surrounding rock in coal mine strata. In this study, rock samples were obtained from construction sites in deep coal mine strata and intact, as well as fissured, rock specimens were prepared and subjected to triaxial compression tests. A numerical model based on the discrete element method was then established and the micro-parameters were calibrated. A total of 288 triaxial compression tests on the rock specimens under different conditions of confining pressure, loading rate, fissure dip angle, and fissure length, were conducted to obtain the triaxial compressive strength of the fractured rock specimens under different conditions. To address the limitations of traditional back propagation (BP) neural networks in solving stochastic problems, a modified BP neural network model was developed using a random factor and an interlayer mean square error corrected network model evaluation function. The traditional and modified BP neural network models were then employed to predict the triaxial compressive strength of the fractured rock specimens. Through comparative analysis, it was found that the modified BP neural network prediction model exhibited smaller errors and significantly reduced overfitting, making it an effective tool for predicting the strength of fractured rocks in deep coal mine strata. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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21 pages, 7696 KB

Open AccessArticle

The Retention and Control Technology for Rock Beams in the Roof of the Roadway: A Case Study

by Xin Wei, Niaz Muhammad Shahani, Xigui Zheng, Jiyu Wang, Yonghui Wang, Chun Chen and Zehui Ren

Processes 2023, 11(6), 1593; https://doi.org/10.3390/pr11061593 - 23 May 2023

Cited by 7 | Viewed by 2274

Abstract

Background: Coal mining requires safe and effective roadway support to ensure production and worker safety. Anchor support is a common method used for controlling the roof of coal seams. This study aims to analyze the effectiveness of different anchor support schemes and provide [...] Read more.

Background: Coal mining requires safe and effective roadway support to ensure production and worker safety. Anchor support is a common method used for controlling the roof of coal seams. This study aims to analyze the effectiveness of different anchor support schemes and provide a theoretical basis for designing safe and effective roadway support. Methods: The authors used a computer simulation tool called FLAC3D to simulate and analyze the spacing between anchor bolts, anchor bolt length, anchor cable length, and effective roadway roof control, and support the schemes at the western wing roadway in the no. 15 coal seam of no. 1 mine of Ping’an Coal Mine. Results: The study found that using different combinations of anchor bolts and cables with varying lengths could effectively control the deformation of the roadway surrounding rock, depending on the spacing between layers of the coal seam. The most effective support schemes were recommended depending on the specific conditions. Conclusion: The study provides a theoretical basis for the design of anchor support in coal mines, which can ensure the safety of production and improve roadway stability. The results could be useful for other mining operations facing similar challenges in roadway support and stability. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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17 pages, 61371 KB

Open AccessArticle

Adaptive Modification of TBM Tunneling in Coal Mine Roadway and Disaster Control Technology for Complex Geological Conditions

by Hongtao Wang, Changkuan Zhou, Qingquan Bi, Hao Zhu, Ziwei Ding and Chenchen Zhang

Processes 2023, 11(5), 1389; https://doi.org/10.3390/pr11051389 - 4 May 2023

Cited by 3 | Viewed by 4016

Abstract

Many mines have introduced the tunnel boring machine (TBM) to improve the efficiency of rock tunneling because of its high propulsion capacity, safe working space, and intelligent equipment. In contrast, the operating environment of coal mines is often under complex geological conditions such [...] Read more.

Many mines have introduced the tunnel boring machine (TBM) to improve the efficiency of rock tunneling because of its high propulsion capacity, safe working space, and intelligent equipment. In contrast, the operating environment of coal mines is often under complex geological conditions such as high ground stress, large depth of burial, high temperature, water damage, and large construction angles, making it difficult to apply traditional TBMs in coal mines. Taking the TBM of Gaojiapu Coal Mine of Zhengtong Coal Industry as an example, this paper introduces the coal mine adaptability transformation and construction technology optimization of the equipment, optimizes the design of the roadheader department of the equipment, increases the support operation space and reduces the empty roof distance, shortens the length of the whole machine and transforms the walking structure to enhance its maneuverability and convenience, and applies the monorail crane to the auxiliary transportation system of TBM. This paper proposes the theory of TBM tunneling disaster control in complex geology, research and discussion on TBM jamming, impact pressure, cooling prevention and control, and water damage in complex geological conditions. The results obtained were applied at the Zhengtong Coal Industry in engineering practice, resulting in an average monthly progress of more than 200 m, which is more than three times more efficient than full rock heaving, and also reduces the work intensity of tunneling personnel and promotes the development of coal mining. The final part of the article looks at the future application of TBMs in coal mining. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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17 pages, 7773 KB

Open AccessArticle

S-Wave Velocity Forecasting Using Drill Cuttings and Deep Hybrid Neural Networks: A Case Study on a Tight Glutenite Reservoir in Mahu Sag, Junggar Basin

by Fengchao Xiao, Xuechen Li and Shicheng Zhang

Processes 2023, 11(3), 835; https://doi.org/10.3390/pr11030835 - 10 Mar 2023

Viewed by 1953

Abstract

S-wave velocity (Vs) is a critical petrophysical parameter for reservoir characterization. It is desirable to predict Vs based on conventional logging data, but the logging cost is high. Therefore, a deep hybrid neural network coupling the convolutional neural network (CNN), Stacked gated recurrent [...] Read more.

S-wave velocity (Vs) is a critical petrophysical parameter for reservoir characterization. It is desirable to predict Vs based on conventional logging data, but the logging cost is high. Therefore, a deep hybrid neural network coupling the convolutional neural network (CNN), Stacked gated recurrent unit (SGRU) is proposed to predict the Vs, where the inputs to the model are drill cutting features. In the proposed CNN-SGRU hybrid model, CNN is adopted to capture the spatial features from the input data, and SGRU is used to extract the temporal patterns of variation from both the forward and backward directions. To illustrate the prediction effect, the glutenite reservoir in the Baikouquan Formation of Mahu Sag, Junggar Basin is taken as an example. Mineral and pore information of drill cuttings, including siliciclastic content, clay content, quartz content, and void area ratio is chosen as the input data of the CNN-SGRU hybrid model. Three indices are used to quantitatively evaluate the prediction performance, including Mean absolute percentage error (MAPE), Root mean square error (RMSE), and Mean absolute error (MAE). The results show that the prediction accuracy of the proposed model is higher than that of the Xu-White model, CNN, and GRU. Furthermore, the results indicate that drill cuttings can replace logging data to predict Vs. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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17 pages, 22867 KB

Open AccessArticle

Model Test Study on Natural Thawing Temperature Field of Artificial Ground Frozen Wall

by Haibing Cai, Longfei Yang, Changqiang Pang, Mengkai Li, Chanrui Lu and Rongbao Hong

Sustainability 2023, 15(4), 3186; https://doi.org/10.3390/su15043186 - 9 Feb 2023

Cited by 4 | Viewed by 2018

Abstract

In order to visualize the evolution and distribution law of the ground temperature field during artificial freezing construction, an indoor model test study was carried out based on the independently constructed hygrothermal coupling artificial ground freezing test platform. The test results show that [...] Read more.

In order to visualize the evolution and distribution law of the ground temperature field during artificial freezing construction, an indoor model test study was carried out based on the independently constructed hygrothermal coupling artificial ground freezing test platform. The test results show that the soil temperature in the freezing process went through the three stages of a steep drop, a slow drop, and stabilization, the earliest closure position of the frozen wall was the intermediate point between two freezing pipes, and the thickness of the frozen wall on different sections showed Section 1 > Section 2 > Section 3 after 61 min of positive freezing. The soil temperature in the natural thawing process went through the four stages of a rapid rise, short hysteresis, a second rapid rise, and a linear slow rise. By fitting the test data, the distribution function of the pipe wall temperature along the pipe length under natural thawing conditions was obtained. The research results can provide a valid basis for the numerical calculation model of a three-dimensional non-uniform natural thawing temperature field and can also provide a reference for the design of settlement grouting under natural thawing conditions. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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21 pages, 5943 KB

Open AccessEditor’s ChoiceArticle

HPHT-Treated Impact Diamonds from the Popigai Crater (Siberian Craton): XRD and Raman Spectroscopy Evidence

by Anatoly Chepurov, Sergey Goryainov, Sergey Gromilov, Egor Zhimulev, Valeriy Sonin, Aleksey Chepurov, Zakhar Karpovich, Valentin Afanasiev and Nikolay Pokhilenko

Minerals 2023, 13(2), 154; https://doi.org/10.3390/min13020154 - 20 Jan 2023

Cited by 6 | Viewed by 2672

Abstract

Phase change and graphitization of diamonds from the Popigai impact crater (Krasnoyarsk Territory, Siberian platform, Russia) exposed to high-pressure high-temperature (HPHT) conditions of 5.5 GPa and 2000–2200 °C are studied by Raman spectroscopy and X-ray diffractometry (XRD). Light-color diamonds of type 1, free [...] Read more.

Phase change and graphitization of diamonds from the Popigai impact crater (Krasnoyarsk Territory, Siberian platform, Russia) exposed to high-pressure high-temperature (HPHT) conditions of 5.5 GPa and 2000–2200 °C are studied by Raman spectroscopy and X-ray diffractometry (XRD). Light-color diamonds of type 1, free from inclusions, with 0 to 10 % lonsdaleite, are more resistant to HPHT effects than dark diamonds of type 2 rich in lonsdaleite and graphite. The lonsdaleite/diamond ratios in lonsdaleite-bearing impact diamonds become smaller upon annealing, possibly because lonsdaleite transforms to cubic diamond simultaneously with graphitization. Therefore, lonsdaleite is more likely a structure defect in diamond than a separate hexagonal phase. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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19 pages, 29714 KB

Open AccessArticle

Experimental Study on the Acoustic Emission Characteristics of Fractured Granite after Repeated High Temperature-Water Cooling

by Dong Zhu, Yuqing Fan, Yang Bai, Xiangling Tao, Leigang Miao and Huiwu Jin

Processes 2023, 11(1), 139; https://doi.org/10.3390/pr11010139 - 3 Jan 2023

Viewed by 1933

Abstract

Using the MTS816 rock mechanics servo tester, an acoustic emission monitoring system and high-speed digital photographic equipment, uniaxial compression tests were conducted on granite specimens containing single fracture slabs after repeated treatment (treatment times 1, 5, 10, 15 and 20) with three types [...] Read more.

Using the MTS816 rock mechanics servo tester, an acoustic emission monitoring system and high-speed digital photographic equipment, uniaxial compression tests were conducted on granite specimens containing single fracture slabs after repeated treatment (treatment times 1, 5, 10, 15 and 20) with three types of high temperature (250, 350 and 450 °C) water cooling, respectively, to analyze the basic mechanical parameters, acoustic emission change characteristics and fracture evolution of the specimens during the uniaxial compression process. It is shown that the heating temperature and the number of treatments not only have a deteriorating effect on the basic mechanical parameters of the specimens but also have an important effect on the changes in the basic parameters of acoustic emission at different compression stages. At 250 °C, the acoustic emission characteristics of the specimens at the initial tightening stage tended to decrease (N = 1 and 5 times) then, increase (N = 10 and 15 times) and then decrease (N = 20 times) as the number of treatments increased. At the same set temperature, the percentage of the bottom amplitude value of the acoustic emission of the specimen gradually decreases, and the percentage of the high amplitude value gradually increases as the number of treatments increases. After the specimen undergoes one and five treatments at 250 °C, the maximum acoustic emission energy value changes less, the maximum acoustic emission energy value decreases with the increase of treatment times in an approximately exponential function, the specimen is transformed from the brittle damage mode to the plastic damage mode and the effect of the prefabricated fracture on the damage of the specimen gradually disappears. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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16 pages, 4044 KB

Open AccessArticle

Prediction of Surface Subsidence of Deep Foundation Pit Based on Wavelet Analysis

by Jindong Zhang and Zhangjianing Cheng

Processes 2023, 11(1), 107; https://doi.org/10.3390/pr11010107 - 30 Dec 2022

Cited by 9 | Viewed by 2381

Abstract

Predicting surface settlement in deep foundation pit engineering plays a central role in the safety of foundation pit construction. Recently, static or dynamic methods are usually applied to predict ground settlement in deep foundation pit projects. In this work, we propose a model [...] Read more.

Predicting surface settlement in deep foundation pit engineering plays a central role in the safety of foundation pit construction. Recently, static or dynamic methods are usually applied to predict ground settlement in deep foundation pit projects. In this work, we propose a model combining wavelet noise reduction and radial basis neural network (XW-RBF) to reduce noise interference in monitoring data. The results show that the XW-RBF model predicts an average relative error of 0.77 and a root average square error of 0.13. The prediction performance is better than the original data prediction results with noise structure and has higher prediction accuracy. The noise data caused by the interference of construction and the surrounding environment in the original data can be removed via the wavelet noise reduction method, with the discreteness of the original data reducing by 30%. More importantly, our results show that the XW-RBF model can reflect the law of data change to predict the future data trend with high credibility. The findings of this study indicate that the XW-RBF model could optimize the deep foundation pit settlement prediction model for high accuracy during the prediction, which inspires the potential application in deep foundation pit engineering. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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19 pages, 8541 KB

Open AccessArticle

Influence of Pipeline Leakage on the Ground Settlement around the Tunnel during Shield Tunneling

by Xin Shi, Yi Cao, Chuanxin Rong, Gangjian An, Houliang Wang and Linzhao Cui

Sustainability 2022, 14(24), 16802; https://doi.org/10.3390/su142416802 - 14 Dec 2022

Cited by 14 | Viewed by 2575

Abstract

Shield tunneling is widely used in urban subway tunnel construction. Old urban underground pipelines generally have small leakages that are difficult to find. The water leakage significantly reduces the stability of the stratum, posing a threat to the safety of tunnel shield construction. [...] Read more.

Shield tunneling is widely used in urban subway tunnel construction. Old urban underground pipelines generally have small leakages that are difficult to find. The water leakage significantly reduces the stability of the stratum, posing a threat to the safety of tunnel shield construction. Therefore, this study established 2D and 3D calculation models for analyzing the law of the leakage diffusion in the ground under water pressure, and the influences of the pipeline leakage range and leakage length on the changes in ground settlement during shield tunneling. The 2D model calculation results show that seepage water mainly diffuses vertically under gravity. As the pipeline leakage gradually reaches a predetermined depth, the simulation results tend to be consistent with the test results. The 3D model is more accurate than the theoretical solution in predicting the ground settlement because it can consider the influences of repeated disturbances in twin tunnel shield construction. The maximum ground surface settlement increases with the extent of the leakage length and leakage range, and the range is the main factor determining the settlement. At the interior of the ground, the seepage water has a greater impact on areas with strong disturbances and large soil losses. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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17 pages, 3455 KB

Open AccessArticle

Study on Blasting Effect Optimization to Promote Sustainable Mining under Frozen Conditions

by Ping Cheng, Yanbo Li, Caiwu Lu, Song Jiang and Hanhua Xu

Sustainability 2022, 14(24), 16479; https://doi.org/10.3390/su142416479 - 9 Dec 2022

Cited by 8 | Viewed by 3207

Abstract

In order to respond to the theme of national green and healthy sustainable development and in response to the problems of large block rates and pollution of the environment after the blast mining of underground rocks in alpine areas, we conducted research on [...] Read more.

In order to respond to the theme of national green and healthy sustainable development and in response to the problems of large block rates and pollution of the environment after the blast mining of underground rocks in alpine areas, we conducted research on the joints of underground rocks and the blastability of frozen rocks. According to the actual geological conditions of an underground mine blasting in Heilongjiang Province, three kinds of joint blasting geometric models were established. The rock mass blasting process of different types of joints was simulated by LS-DYNA software and the influence law of joints on rock mass blasting was summarized. The blasting crater test and the triaxial compression test of frozen rock were carried out. Combined with the blasting fragmentation characterization function (R-R and G-G-S), the blasting fragmentation, strength and stiffness of frozen rock at different temperatures were obtained. Based on the above, the blasting parameters of a multi-joint underground rock mass in an alpine region were optimized: hole spacing 4.0 m, row spacing 2.5 m, hole depth 11.5 m, V-type initiation network. The optimized blasting parameters significantly improved the mining efficiency and reduced the large lump rate to 3.1%. In order to promote the sustainable exploitation of resources in alpine regions, this study optimized the blasting technology of underground rock mass. Full article

(This article belongs to the Topic Advanced Materials and Technologies in Deep Rock Engineering)

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