Geohazard Mechanics最新文献

In the construction process of soft rock tunnels, determining a reasonable amount of reserved deformation is important to ensure the tunnel stability. This article presents the viscoelastic solution of reserved deformation for deep soft rock tunnels considering the support effects. Based on the analytical solution of the Burgers model, the expression of surrounding rock displacement was derived by considering reserved deformation and optimal reserved deformation. Subsequently, based on numerical simulation experiments, the variation laws and errors of the numerical and analytical solutions of the expressions of reserved deformation and surrounding rock displacement were analyzed. To gain a better understanding of the factors that affect reserved deformation, the factors influencing the expression of optimal reserved deformation were analyzed. The errors in the numerical simulation and analytical solution results were within 10%. This study could provide a theoretical basis for determining the amount of reserved deformation and analyzing the variation law of surrounding rock affected by the amount of reserved deformation.

To investigate the deformation characteristics and instability mechanism of the transportation hub under downward traversal conditions of the double-track super-large diameter shield tunnel, take the example of Beijing East Sixth Ring Road into the ground reconstruction project. Using the field experimental monitoring method and numerical simulation method, after verifying the accuracy of the model, this manuscript begins to unfold the analysis. The results show that, without any deformation prevention and control measures, The basement raft of the underground structure of the transportation hub will produce a deformation difference of 18 ​mm, and the tensile stress is more than 1.43 ​MPa, the inhomogeneous deformation and structural cracking will lead to structural instability and groundwater surges, which seriously affects the safe operation of the transportation hub station. When control measures are taken, the deformation and stress of the base raft slab of the underground structure of the transportation hub are within the prescribed limits, which can ensure the safe operation of the station. The displacement of the base slab of the underground structure in the horizontal direction of the cross-section is all pointing to the east, and the overall trend is to shift from the first tunnel to the backward tunnel. The horizontal displacement of the base slab in the direction of the tunnel axis all points to the beginning of the crossing, and the displacement of the slab in the vertical direction is distributed as "rising in the middle and sinking in the surroundings". For a two-lane super-large diameter shield tunnel penetrating an underground structure, there are two mechanical effects: unloading rebound and perimeter rock pressure. The above deformation characteristics are the superposition effect produced by the two, and this fine assessment of the deformation of the raft foundation provides a scientific basis for formulating the deformation control countermeasures of the crossing project. At the same time, it makes up for the blank of the double-track super-large diameter shield tunnel down through the transportation hub project.

Coal-related accidents are prevalent in China, often attributed to the intricate geology and challenging working conditions of mines. This study seeks to determine the patterns of these accidents by examining the characteristics of an accidents database, considering regional, temporal, mining method, and classification distribution characteristics. The analysis centers on all significant coal accidents (involving three or more fatalities) that occurred in China from 2017 to 2022, as documented in China’s (excluding Hong Kong, Macao, and Taiwan) national coal-mining safety accident report. Over the most recent six years, roof falls and gas explosions have emerged as the most common types of accident. Case studies were conducted to comprehensively investigate the histories and underlying causes of these incidents. Countermeasures are proposed from three perspectives: prospective measures, optimization strategies, and enterprise management.

In recent years, many useful experimental results on the cracking behaviors of fractured rocks have been obtained via uniaxial, biaxial, triaxial, and Split Hopkinson Pressure Bar (SHPB) tests. In this paper, the influence of the inclination angle of flaws, number of flaws, and patterns of cracks on the mechanical properties during the failure process under static loading and dynamic loading conditions is introduced and reviewed. The results show that the presence of cracks can decrease the strengths of precracked specimens, and the inclination angles, numbers, and crack patterns of pre-existing flaws can change the mechanical properties and cracking behaviors of precracked specimens. Under static loading, the closer the inclination angle is to 90°, the greater the strength, the elastic modulus, and the peak strain of the precracked specimen. However, under dynamic loading, the influence of the inclination angle varies, and the strength can increase or decrease, possibly in a V-shaped manner. This change can be determined by multiple factors, such as the loading path, the materials of the precracked specimen, and the number of pre-existing cracks. Under dynamic loading, the precracked specimen usually exhibits an X-shaped conjugated failure. Additionally, some problems in the study of the cracking behaviors of fractured rocks and related future research are described and presented, and corresponding suggestions and solutions are given. In particular, excavation in deep rock engineering, support of the rock surrounding the tunnel, and mining engineering have important scientific and engineering significance.

In the 21st century, the surge in natural and human-induced disasters necessitates robust disaster management frameworks. This research addresses a critical gap, exploring dynamics in the successful implementation and performance monitoring of disaster management. Focusing on eleven key elements like Vulnerability and Risk Assessment, Training, Disaster Preparedness, Communication, and Community Resilience, the study utilizes Scopus Database for secondary data, employing Text Mining and MS-Excel for analysis and data management. IBM SPSS (26) and IBM AMOS (20) facilitate Exploratory Factor Analysis (EFA) and Structural Equation Modeling (SEM) for model evaluation.

The research raises questions about crafting a comprehensive, adaptable model, understanding the interplay between vulnerability assessment, training, and disaster preparedness, and integrating effective communication and collaboration. Findings offer actionable insights for policy, practice, and community resilience against disasters. By scrutinizing each factor's role and interactions, the research lays the groundwork for a flexible model. Ultimately, the study aspires to cultivate more resilient communities amid the escalating threats of an unpredictable world, fostering effective navigation and thriving.

Water leakage inspection in the tunnels is a critical engineering job that has attracted increasing concerns. Leakage area detection via manual inspection techniques is time-consuming and might produce unreliable findings, so that automated techniques should be created to increase reliability and efficiency. Pre-trained foundational segmentation models for large datasets have attracted great interests recently. This paper proposes a novel SAM-based network for accurate automated water leakage inspection. The contributions of this paper include the efficient adaptation of the SAM (Segment Anything Model) for shield tunnel water leakage segmentation and the demonstration of the application effect by data experiments. Tunnel SAM Adapter has satisfactory performance, achieving 76.2 ​% mIoU and 77.5 ​% Dice. Experimental results demonstrate that our approach has advantages over peer studies and guarantees the integrity and safety of these vital assets while streamlining tunnel maintenance.

China is a mountainous country with highly developed road geologic hazards, which pose a great threat to the construction and operation of highways, bridges, and tunnels and to the safety of people and property. This paper discussed the types, basic features, formation, and prevention conditions of road geologic hazards in China based on field research and study data collected thus far. The study considered an urban area of a city in southwest China as the center and a geological field investigation was performed over a total of 282 ​km on three important lifeline projects. The results show: Types of geologic hazards along the highways are mainly avalanches, debris flows, and landslides, respectively. Among them, the landslips are mainly distributed along the roads, with slip, dumping, and wrong break types as the main ones; the debris flows are widely distributed, mainly concentrated in the river valleys; and the unstable slopes are relatively few in number. Geological disasters are characterized by large-scale and concentrated triggering in time and space, and a single disaster can easily trigger other disasters, thus forming a chain of disasters. Neotectonic movement, seismic activity, topography, climatic conditions, stratigraphic lithology, and human activities are important factors leading to geologic hazards in the study area. This study is of great practical significance for reducing the occurrence of roadbed diseases and prolonging the service life of highways.

Aiming at the deformation control problem of the tunnel entrance crossing the spoil heap at the Xialao junction, this paper adopts the micropile combined with the coupling beams method to treat the spoiled layers. The results show that the excavation of the tunnel after the construction of the micropile and coupling beam will cause vertical deformation of the tunnel and the slope surface. The main reason is that the soil layer structure is loose, and the tunnel excavation causes the whole displacement of the loose body. In addition, the buried depth of the tunnel is shallow, so it cannot form an effective soil arch. The stability process after the construction of the micropile method is the process of stress redistribution, and the rock and soil are gradually compressed and compacted. That is, the construction by the micropile method changes the surrounding rock level of the tunnel and reduces the height of the soil arch. Therefore, it is suggested that the tunnel excavation should be carried out when the micropile is constructed after the soil layers are consolidated completely. The micropile method treats the loose spoiled soil at the tunnel entrance, which saves 73% of the total cost compared with the scheme of directly digging out the accumulation, and the economic benefit is very obvious.

As a widely used rock excavation method in civil and mining construction works, the blasting operations and the induced side effects are always investigated by the existing studies. The occurrence of flyrock is regarded as one of the most important issues induced by blasting operations, since the accurate prediction of which is crucial for delineating safety zone. For this purpose, this study developed a flyrock prediction model based on 234 sets of blasting data collected from Sugun Copper Mine site. A stacked multiple kernel support vector machine (stacked MK-SVM) model was proposed for flyrock prediction. The proposed stacked structure can effectively improve the model performance by addressing the importance level of different features. For comparison purpose, 6 other machine learning models were developed, including SVM, MK-SVM, Lagragian Twin SVM (LTSVM), Artificial Neural Network (ANN), Random Forest (RF) and M5 Tree. This study implemented a 5-fold cross validation process for hyperparameters tuning purpose. According to the evaluation results, the proposed stacked MK-SVM model achieved the best overall performance, with RMSE of 1.73 and 1.74, MAE of 0.58 and 1.08, VAF of 98.95 and 99.25 in training and testing phase, respectively.

With the increasing depth of coal mining each year, rock burst has emerged as one of the most severe dynamic disasters in deep mining. The research status of rock burst prevention and control theory is summarized. Focused on deep coal mining, the major issues encountered in researching the prevention theory of rock bursts are summarized. Subsequently, the scientific connotation theory of stress relief-support reinforcement cooperative prevention and control of rock bursts in deep coal mines is proposed. Then, the mechanisms underlying the major research directions of the theory of stress relief-support reinforcement coordinated prevention and control and present a preliminarily theoretical framework for stress relief-support reinforcement coordinated prevention and control are outlined. To tackle the key scientific problems in the coordinated prevention and control of rock bursts on relief and support in deep mine, the in-depth research based on the synergetic theory is conducted. This involved exploring the principles of near-field coal mass stress relief, near-field roof and floor stress relief, and anchor support. Additionally, the stress-energy evolution processes of the roadway near-field surrounding rock structure under various stress relief and anchor support modes be analyzed. Subsequently, a mechanical model for the optimized matching of stress relief surrounding rock and anchor support is established, with the control of the rock burst energy source at its core. Finally, the principle of collaborative prevention and control of deep mining rock burst stress relief and support from the perspectives of structural synergy, strength synergy, and stiffness synergy is elucidated. This insight is expected to provide theoretical support for the research and development of designs and techniques for deep mining rock burst prevention and control.