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Open AccessEditorial

Intelligent Technologies in Geotechnical Engineering and Geological Hazards

by Yongsheng Zhou

Appl. Sci. 2026, 16(15), 7794; https://doi.org/10.3390/app16157794 - 5 Aug 2026

Viewed by 265

Abstract

Intelligent technology provides us with a new method to understand geotechnical engineering and geomechanics and has widespread application in geotechnical engineering and geological hazards [...] Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

Research

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15 pages, 5776 KB

Open AccessArticle

The Concentration Levels of Cr and Mo in the Soils of Beijing and Their Comparison with Other Capital Cities

by Yonglong An, Wenjun Cui, Qingjie Gong, Yuan Jiang and Yong Huang

Appl. Sci. 2026, 16(13), 6801; https://doi.org/10.3390/app16136801 - 7 Jul 2026

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Abstract

With the growing potential correlation between chromium (Cr), molybdenum (Mo), and human health, public attention to these elements has increased markedly. In Beijing, the capital of China, research on the concentration levels of Cr and Mo is urgently needed. In recent years, soil [...] Read more.

With the growing potential correlation between chromium (Cr), molybdenum (Mo), and human health, public attention to these elements has increased markedly. In Beijing, the capital of China, research on the concentration levels of Cr and Mo is urgently needed. In recent years, soil geochemical surveys have been conducted in the Beijing region, with a scale of 1:100,000 in mountainous areas (yielding 8575 data points) and 1:50,000 in plain areas (yielding 29,551 data points). These surveys provide a robust dataset for elucidating the concentrations and distribution patterns of soil elements. In surface soil samples from Beijing (n = 38,126), the mean concentrations of Cr and Mo were 55.7 µg/g and 0.67 µg/g, respectively. Recently, scholars have proposed a 19-level fixed-value method for Mo concentrations. Based on this, the 19-level fixed-value method for Cr concentrations is proposed to facilitate cross-element comparisons. This method classifies the elemental concentrations from its detection limit to its cut-off grade of mineralization into 19 levels on 18 fixed values. With this method, the concentration levels of Cr and Mo in Beijing soils are both at the fifth level on their mean values, which belong to the background level. To compare the Cr and Mo concentrations in soils with other capital cities, statistical parameters of Cr from 20 capital cities and Mo from 11 capital cities were collected. The results show that the mean Cr concentration levels in the 20 cities range from 2 to 10, while the mean Mo concentration levels in the 11 cities range from 5 to 10. In these capital cities, the Cr level of Beijing is at the middle level, and the Mo level is at the low level, which indicates the cross-element comparison on the 19-level fixed-value method. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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65 pages, 51400 KB

Open AccessArticle

Pre-Event Estimation of County-Level Human Casualty Projections in Southwestern China Based on the Spatial Aggregation of Village-Scale Lethality Data

by Nan Zhang, Xiwei Fan, Chaoxu Xia, Nan Xi, Jing Wang and Gaozhong Nie

Appl. Sci. 2026, 16(12), 6257; https://doi.org/10.3390/app16126257 - 22 Jun 2026

Cited by 1 | Viewed by 528

Abstract

An earthquake lethality model was employed to assess the casualty distribution in Yunnan, Guizhou, and Sichuan provinces, taking into account the ground motion acceleration with different 50-year exceedance probabilities. When the probability is 63%, fatalities are predominantly concentrated in central and south-western Yunnan, [...] Read more.

An earthquake lethality model was employed to assess the casualty distribution in Yunnan, Guizhou, and Sichuan provinces, taking into account the ground motion acceleration with different 50-year exceedance probabilities. When the probability is 63%, fatalities are predominantly concentrated in central and south-western Yunnan, as well as central, southern, and western Sichuan. At a 10% probability, the peaks of the casualties are observed in southern, eastern, and central Sichuan. In Yunnan (excluding the northwest and southeast regions), the casualty density exhibits unevenness, whereas Guizhou experiences relatively low casualties (except in the eastern and western mountainous areas). Xichang incurs the most substantial losses, followed by Lancang. Xundian, Songming, and Dongchuan demonstrate a high propensity for fatalities, and the risk is relatively high in the vicinity of the Longjiang and Nujiang faults. If a destructive earthquake occurs near these areas within the next 50 years, the probability of a Level-I emergency response exceeds 10%. When the ground motion acceleration doubles (especially when the exceedance probability drops to 2% in 50 year and 0.1% in a year), the predicted number of casualties remains relatively stable. However, the grid of the casualty population exhibits a higher degree of spatial concentration of casualties, and the disaster-affected area expands. There exists no linear correlation between earthquake-induced fatalities and the ground motion level. When the 50-year exceedance probability decreases from 63% to 10%, the casualty rate may increase by several dozen times. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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32 pages, 11879 KB

Open AccessArticle

A Physics-Informed Online Learning Framework for Landslide Displacement Prediction

by Jie Zhou, Nengpan Ju, Chaoyang He and Mingli Xie

Appl. Sci. 2026, 16(12), 6003; https://doi.org/10.3390/app16126003 - 13 Jun 2026

Cited by 1 | Viewed by 695

Abstract

Current landslide displacement prediction models often suffer from insufficient integration between physical mechanisms and data-driven approaches, weak model generalizability, and limited operational applicability. To address these issues, this study develops a physics-informed online learning framework for landslide displacement prediction. The core of this [...] Read more.

Current landslide displacement prediction models often suffer from insufficient integration between physical mechanisms and data-driven approaches, weak model generalizability, and limited operational applicability. To address these issues, this study develops a physics-informed online learning framework for landslide displacement prediction. The core of this framework is a Physics-informed Long Short-Term Memory network (Phys-LSTM). By embedding discretized forms of the stress balance, creep constitutive, and kinematic equations as hard constraints into the LSTM’s gating mechanisms and loss function, the model ensures physically consistent predictions and enhanced interpretability throughout the learning process. Leveraging real-time data streams from the Sichuan Provincial Geological Hazard Monitoring and Warning Platform, we developed an online processing pipeline for real-time multi-source data ingestion, automated quality control, spatiotemporal alignment, and physics-informed feature engineering. A progressive three-stage learning algorithm was designed to support model cold-start, incremental training, and rolling prediction. Validation across 45 model-development landslide sites and one independent application case demonstrated the framework’s significant superiority over traditional models in displacement prediction accuracy (RMSE ≤ 1.78 mm, R² ≥ 0.96), cross-site generalization stability, and its capability to capture accelerated deformation phases. This research indicates that deeply integrating geomechanical prior knowledge into an online learning framework can effectively improve the reliability, interpretability, and operational applicability of landslide displacement prediction models, thereby providing methodological support for subsequent landslide early warning applications. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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40 pages, 7401 KB

Open AccessArticle

Seismic Hazard Area Prediction Based on Slip and Locking Rates of Active Faults in Northern Ningxia, China

by Nan Zhang, Xiwei Fan, Jing Wang and Gaozhong Nie

Appl. Sci. 2026, 16(9), 4282; https://doi.org/10.3390/app16094282 - 28 Apr 2026

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Abstract

This research employs the ITRF2014 framework to conduct an analysis of Eurasian GNSS data, thereby acquiring the recent velocity and strain rate fields in the Ningxia–Inner Mongolia border region, as well as in the Yinchuan and Lingwu regions of western China. It also [...] Read more.

This research employs the ITRF2014 framework to conduct an analysis of Eurasian GNSS data, thereby acquiring the recent velocity and strain rate fields in the Ningxia–Inner Mongolia border region, as well as in the Yinchuan and Lingwu regions of western China. It also provides in-depth insights into the relative movements, slip rates, and locking positions of active faults in these areas. Based on the elastic dislocation theory, a constraint model is constructed to perform numerical simulations of active faults. This enables the inversion of strike–slip, dip–slip, and slip deficit rates, along with the locking degree. Fault lockings are identified at the southern extremities of the northern and southern segments of the Niushoushan–Luoshan fault, the western ends of the Xiangshan–Tianjingshan fault zone, and the eastern segment of the Gancanling Fault. In Yinchuan, local locking is detected below 15 km along the southern part of the Helan Mountain eastern fault. The Bayannula Mountain Fault exhibits an uneven locking distribution, while the locking degree of the western margin fault of Zhuozi Mountain increases from the southwest to the northeast, with the fault being locked in the Etuoke Banner section. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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21 pages, 2522 KB

Open AccessArticle

Integrating SVR Optimization and Machine Learning-Based Feature Importance for TBM Penetration Rate Prediction

by Halil Karahan and Devrim Alkaya

Appl. Sci. 2026, 16(1), 355; https://doi.org/10.3390/app16010355 - 29 Dec 2025

Cited by 9 | Viewed by 2042

Abstract

In this study, a Support Vector Regression (SVR) model was developed to predict the rate of penetration (ROP) during tunnel excavation, and its hyperparameters were optimized using Grid Search (GS), Random Search (RS), and Bayesian Optimization (BO). The results indicate that BO reached [...] Read more.

In this study, a Support Vector Regression (SVR) model was developed to predict the rate of penetration (ROP) during tunnel excavation, and its hyperparameters were optimized using Grid Search (GS), Random Search (RS), and Bayesian Optimization (BO). The results indicate that BO reached the optimal parameter set with only 30–50 evaluations, whereas GS and RS required approximately 1000 evaluations. In addition, BO achieved the highest predictive accuracy (R² = 0.9625) while reducing the computational time from 25.83 s (GS) to 17.31 s. Compared with the baseline SVM model, the optimized SVR demonstrated high accuracy (R² = 0.9610–0.9625), strong stability (NSE = 0.9194–0.9231), and low error levels (MAE = 0.0927–0.1099), clearly highlighting the critical role of hyperparameter optimization in improving model performance. To enhance interpretability, a feature importance analysis was conducted using four machine learning methods: Random Forest (RF), Bagged Trees (BT), Support Vector Machines (SVM), and the Generalized Additive Model (GAM). The relative contributions of BI, UCS, ALPHA, and DPW to ROP were evaluated, providing clearer insight into the model’s decision-making process and enabling more reliable engineering interpretation. Overall, integrating hyperparameter optimization with feature importance analysis significantly improves both predictive performance and model explainability. The proposed approach offers a robust, generalizable, and scientifically sound framework for TBM operations and geotechnical modeling applications. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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20 pages, 7968 KB

Open AccessArticle

Horizontal PGA Estimates for Varying Deep Geological Conditions—A Case Study of Banja Luka

by Borko Bulajić, Silva Lozančić, Senka Bajić, Anka Starčev-Ćurčin, Miloš Šešlija, Miljan Kovačević and Marijana Hadzima-Nyarko

Appl. Sci. 2025, 15(12), 6712; https://doi.org/10.3390/app15126712 - 15 Jun 2025

Cited by 2 | Viewed by 2010

Abstract

In this study, the city of Banja Luka is used as a case study to evaluate horizontal PGA values in regions with a history of moderate to strong earthquakes and with different deep geological conditions. We present regional attenuation equations for PGA that [...] Read more.

In this study, the city of Banja Luka is used as a case study to evaluate horizontal PGA values in regions with a history of moderate to strong earthquakes and with different deep geological conditions. We present regional attenuation equations for PGA that can capture both the impacts of deep geology and local soil conditions. A PSHA study for a site in Banja Luka was carried out using the developed empirical scaling equations and compared to all previous seismic hazard estimations for the same region. The data indicate that variations in deep geological conditions may have a greater impact on PGA values than local soil effects. Given the scarcity of scaling equations that consider deep geology in addition to local soil conditions, we believe this case study is a step toward developing more accurate PGA estimates for comparable regions. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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16 pages, 5881 KB

Open AccessArticle

PGA Estimates for Vertical Ground Motion and Varying Deep Geology Site Surroundings—A Case Study of Banja Luka

by Borko Bulajić, Silva Lozančić, Senka Bajić, Anka Starčev-Ćurčin, Miloš Šešlija, Miljan Kovačević and Marijana Hadzima-Nyarko

Appl. Sci. 2025, 15(12), 6542; https://doi.org/10.3390/app15126542 - 10 Jun 2025

Cited by 3 | Viewed by 1996

Abstract

Vertical PGA is frequently included in civil engineering regulations simply by multiplying the horizontal PGA by a constant. Moreover, most design codes, including Eurocode 8, do not consider the impact of the local soil on vertical ground motion at all. In this study, [...] Read more.

Vertical PGA is frequently included in civil engineering regulations simply by multiplying the horizontal PGA by a constant. Moreover, most design codes, including Eurocode 8, do not consider the impact of the local soil on vertical ground motion at all. In this study, we demonstrate that such practices increase earthquake risks. The article examines vertical PGA strong-motion estimations for the city of Banja Luka. Banja Luka serves as a case study for areas with records of moderate to strong earthquakes and diverse deep geological conditions. Regional equations for scaling vertical PGA are presented. The vertical PGA values and vertical to horizontal PGA ratios are calculated and analyzed. The findings indicate that the vertical to horizontal PGA ratios for the rock sites depend on the source-to-site distance and deep geology and fall between 0.30 and 0.66. Hence, these ratios cannot be approximated by a single value of 0.90 and 0.45, as specified by Eurocode 8 for Type 1 and Type 2 spectra, respectively. Moreover, the results show that the deep geology effects on vertical ground motion can exceed the local soil effects. When the amount of recorded data from comparable areas increases, we will be able to properly calibrate the existing scaling equations and obtain more reliable estimates of vertical PGA. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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19 pages, 3048 KB

Open AccessArticle

Integrating Radon/Thoron and Gamma Radiation Exposure for a Realistic Estimation of Dose Arising from Building Materials

by Mirsina M. Aghdam and Quentin Crowley

Appl. Sci. 2025, 15(12), 6470; https://doi.org/10.3390/app15126470 - 9 Jun 2025

Cited by 3 | Viewed by 2001

Abstract

Long-term exposure to radon, thoron, and gamma radiation from building materials poses a significant health risk to occupants. Current methods for estimating radiation doses often fail to consider the combined impact of these sources. Based on commonly used building materials available on the [...] Read more.

Long-term exposure to radon, thoron, and gamma radiation from building materials poses a significant health risk to occupants. Current methods for estimating radiation doses often fail to consider the combined impact of these sources. Based on commonly used building materials available on the Irish market, this paper advocates for the development of a comprehensive dose estimation model that accounts for radon, thoron, and gamma radiation. To achieve this, several models and various scenarios (e.g., ventilation conditions and building characteristics) are integrated to convert radon and thoron gas doses into a common unit recognized in the existing literature. This approach enables the comparison of combined dose values with accepted radiation thresholds for building materials, typically set at 1 mSv, alongside data on material compositions. Previous studies suggested gamma radiation doses in Irish materials are unlikely to exceed 1 mSv annually. Our findings confirm this, showing gamma doses <0.4 mSv for all materials. However, combined radon–thoron doses exceeded thresholds in altered granites (e.g., Galway granite: 3.90 mSv), with thoron contributing ≤93% of total exposure due to uranium/thorium-rich minerals (e.g., monazite, zircon). Ventilation proved critical—high airflow (10 m³/h) reduced thoron doses by 90–95%, while current gamma-focused safety indices (I-index ≤ 1) inadequately addressed combined risks. These results highlight the previously underestimated importance of thoron and the necessity of multi-parameter models for regulatory compliance. The study establishes a novel framework to evaluate holistic radiation risks, urging revised standards that prioritize ventilation strategies and material mineralogy to protect public health in residential and commercial built environments. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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16 pages, 1393 KB

Open AccessArticle

Thermal Damage Characterization and Modeling in Granite Samples Subjected to Heat Treatment by Leveraging Machine Learning and Experimental Data

by Gabit Sansyzbekov, Amoussou Coffi Adoko and Paul Mathews George

Appl. Sci. 2025, 15(11), 6328; https://doi.org/10.3390/app15116328 - 4 Jun 2025

Cited by 2 | Viewed by 1729

Abstract

High temperatures significantly affect the physical and mechanical properties of rocks in deep geoengineering projects, such as geothermal development, deep mining, and the geological disposal of nuclear waste. Therefore, it is essential to explore the relationship between the thermal damage (TD) of granite [...] Read more.

High temperatures significantly affect the physical and mechanical properties of rocks in deep geoengineering projects, such as geothermal development, deep mining, and the geological disposal of nuclear waste. Therefore, it is essential to explore the relationship between the thermal damage (TD) of granite and its influencing factors. This paper characterizes the TD of granite specimens subjected to high temperatures of up to 800 °C and proposes a predictive model for this thermal damage. A database, which includes publicly available experimental data of advanced microscopic observations of granite specimens exposed to high-temperature treatments and their changes in physical and mechanical properties, was compiled and analyzed. The collected data revealed a consistent trend: crack development among quartz, feldspar, and biotite minerals was observed to intensify notably between 400 °C and 600 °C, as indicated by changes in the mechanical properties. Based on these characteristics, the relationships between TD and its influential parameters were determined using regression models and several machine learning algorithms. The derived models indicated good predictability performance with a coefficient of determination (R²) varying between 0.60 and 0.97, with the boosted ensemble tree model being the best. Nevertheless, mineral contents were not found to be good predictors of TD, even if they control the evolution of the crack during the heat treatment. It was concluded that the findings of this study could serve as a valuable tool for assessing the thermal damage of rocks. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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25 pages, 11254 KB

Open AccessArticle

Pseudotachylyte Formation in Brittle–Ductile Transition of the Anning River Fault Zone: Implications for Seismic Processes

by Wenhao Dai, Yongsheng Zhou, Huiru Lei, Xi Ma, Jiaxiang Dang, Sheqiang Miao, Shimin Liu and Changrong He

Appl. Sci. 2025, 15(11), 5870; https://doi.org/10.3390/app15115870 - 23 May 2025

Viewed by 1592

Abstract

Pseudotachylytes and cataclasites record transient seismic slips within the brittle–ductile transition zone and ductile flow layers. Investigating the mechanisms of pseudotachylytes can provide the most direct geological evidence for revealing seismic fault slip and coseismic processes. We investigate the deformation and chemical composition [...] Read more.

Pseudotachylytes and cataclasites record transient seismic slips within the brittle–ductile transition zone and ductile flow layers. Investigating the mechanisms of pseudotachylytes can provide the most direct geological evidence for revealing seismic fault slip and coseismic processes. We investigate the deformation and chemical composition of pseudotachylytes, cataclasites, and mylonites collected from the Anning River fault zone in this study. Three kinds of pseudotachylyte veins were found in granite gneiss and cataclasite. Microstructural analyses show that pseudotachylytes and cataclasites developed within granitic gneiss and mylonites, and EBSD analysis indicates granitic gneiss deformed at temperatures of 250–350 °C. All of the pseudotachylytes are enriched in Fe and Ca, with SiO₂ content closely resembling that of the wall rock of granitic gneiss. The geochemical results indicate that pseudotachylytes originated from the in situ melting of granitic gneiss, which was produced during coseismic frictional heating. Based on the deformation and geochemical data of mylonites, cataclasites, and pseudotachylytes, a simple model of the seismogenic layer is established for rock deformation during coseismic, post-seismic relaxation, and interseismic periods. Mylonite represents the rheological flow of the brittle–ductile transition zone during interseismic periods, cataclasites display brittle fracturing during coseismic rupture, and pseudotachylytes stand for localized melting induced by coseismic frictional heating. During the post-seismic relaxation, crack healing and static recrystallization of quartz occur. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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15 pages, 5267 KB

Open AccessArticle

Field Test and Numerical Simulation Study of Bearing Characteristics of Combined Post-Grouted Piles for Railway Bridges

by Runze Zhang, Zilong Guo, Weiming Gong and Zhihui Wan

Appl. Sci. 2025, 15(1), 335; https://doi.org/10.3390/app15010335 - 1 Jan 2025

Cited by 4 | Viewed by 2099

Abstract

Utilizing the results of static load tests using the self-balancing method on two large-diameter bored piles from the Huaiyang Left Line Special Bridge Project of the Lianyungang–Zhenjiang Railway, this study aims to investigate the effect of combined tip-and-side post-grouting on the bearing characteristics [...] Read more.

Utilizing the results of static load tests using the self-balancing method on two large-diameter bored piles from the Huaiyang Left Line Special Bridge Project of the Lianyungang–Zhenjiang Railway, this study aims to investigate the effect of combined tip-and-side post-grouting on the bearing characteristics of post-grouted piles in railway bridges. The difference in bearing performance between individual piles before and after grouting was evaluated using a comparative analysis. The results show that the bearing capacity of the pile foundations is greatly increased by combined tip-and-side post-grouting. In particular, following grouting, a single pile’s maximum bearing capacity rises from 32.99% to 38.42%. The combined post-grouting produces a compressed grout that enhances the mechanical characteristics of the pile–soil contact, resulting in a significant increase in side resistance all the way along the pile. The combined post-grouting also optimizes the performance of the tip resistance, resulting in a more rapid response as the pile tip displacement increases. Additionally, the combined post-grouting modifies the pile shaft’s load transfer mechanism by increasing the tip resistance’s contribution to the pile foundation’s ultimate bearing capacity and moving the bearing’s center of gravity closer to the pile end. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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21 pages, 11071 KB

Open AccessArticle

Element Migration of Mineralization-Alteration Zones and Its Geological Implication in the Beiya Porphyry–Skarn Deposit, Northwestern Yunnan, China

by Fei Liu, Runsheng Han, Yuxinyue Guo, Mingzhi Wang and Wei Tan

Appl. Sci. 2024, 14(21), 9653; https://doi.org/10.3390/app14219653 - 22 Oct 2024

Cited by 2 | Viewed by 4446

Abstract

Porphyry and the associated skarn-type deposit is one of the most important types of ore deposits worldwide, which usually exhibit significant zoning of mineralization-alteration, but the research on element migration in these mineralization-alteration zones is relatively weak. The Beiya porphyry–skarn gold-polymetallic deposit is [...] Read more.

Porphyry and the associated skarn-type deposit is one of the most important types of ore deposits worldwide, which usually exhibit significant zoning of mineralization-alteration, but the research on element migration in these mineralization-alteration zones is relatively weak. The Beiya porphyry–skarn gold-polymetallic deposit is a super-large Cenozoic deposit located in the Sanjiang metallogenic belt, northwestern Yunnan, China. In this paper, through a detailed analysis of mineralization and alteration zoning and its element migration regularity, the findings are as follows: (1) Three types of hydrothermal alteration—porphyry alteration, contact alteration, and wall-rock alteration—are developed, and porphyry alteration includes potassic, phyllic, propylitic, and argillic alteration; (2) five types of mineralization—porphyry-type Cu–Au–(Mo), skarn-type Au–Fe–(Cu), hydrothermal vein-type Au–Fe, distal hydrothermal-type Pb-polymetallic, and oxidizing-leaching enriched-type Au—occur in a diversity of forms, which are dominantly controlled by structures and lithologies; (3) concentric-banded mineralization-alteration zones are exhibited centrally from the alkaline porphyry outward or upward, namely [porphyry alteration] potassic → phyllic → propylitic → argillic → [contact alteration] skarnitization–marbleization → [wall-rock alteration] marbleization–silicification–calcitization; (4) porphyry-type mineralization predominantly forms within potassic and phyllic zones, while skarn-type mineralization occurs in contact alteration zones, and proximal and distal hydrothermal (vein)-type mineralization are commonly distributed in marbleization–silicification–calcitization alteration zones; and (5) element migration analysis demonstrates a significantly lateral and vertical zoning in the metallogenic element association of Cu–Mo → Cu–Au → Au–Fe–Cu → Au–Fe → Pb–Zn–Au–Ag–Fe from alkaline porphyry outward to the wall-rock. The mineralization-alteration zoning model indicates the Beiya deposit has similar mineralization and alteration zone characteristics to the typical porphyry copper system; and element migration within mineralization-alteration zones provides new scientific information for understanding the metallogenic regularity and prospecting at Beiya, as well as the similar types of deposits in the Sanjiang metallogenic belt and elsewhere in the world. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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Review

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18 pages, 2421 KB

Open AccessReview

Frictional Experiments on Granitic Faults: New Insights into Continental Earthquakes and Micromechanical Mechanisms

by Huiru Lei, Shimin Liu and Wenhao Dai

Appl. Sci. 2025, 15(13), 7207; https://doi.org/10.3390/app15137207 - 26 Jun 2025

Viewed by 1777

Abstract

Granitic faults within the crystalline upper-to-middle continental crust play a critical role in accommodating tectonic deformation and controlling earthquake nucleation. To better understand their frictional behavior, we review experimental studies conducted under both dry and hydrothermal conditions using velocity-stepping (VS), constant-velocity (CV), and [...] Read more.

Granitic faults within the crystalline upper-to-middle continental crust play a critical role in accommodating tectonic deformation and controlling earthquake nucleation. To better understand their frictional behavior, we review experimental studies conducted under both dry and hydrothermal conditions using velocity-stepping (VS), constant-velocity (CV), and slide-hold-slide (SHS) tests. These approaches allow the quantification of frictional strength, velocity dependence, and healing behavior across a range of conditions. Our synthesis highlights that the friction coefficient of granite gouges decreases with increasing temperature and pore fluid pressure, decreasing slip velocity, and increasing slip displacement. The velocity-weakening regime shifts to higher temperatures with increasing slip velocity or decreasing pore fluid pressure. Temperature, normal stress, pore fluid pressure, and slip velocity interact to modulate frictional stability. In particular, microstructural observations reveal that grain size reduction, pressure solution creep, and fluid-assisted chemical processes are key mechanisms governing transitions between velocity-weakening and velocity-strengthening regimes. These insights support the growing application of microphysical-based models, which integrate micromechanical processes and offer improved extrapolation from the laboratory to natural fault systems compared to classical rate-and-state friction laws. The collective evidence underscores the importance of considering fault rheology in a temperature- and fluid-sensitive context, with implications for interpreting seismic cycle behavior in continental regions. Full article

(This article belongs to the Special Issue Intelligent Technologies in Geotechnical Engineering and Geological Hazards)

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