Geohazard Mechanics最新文献

Buckling failure of layered rock slopes due to self-weight is common in mountain areas, especially for high and steep slope, and it frequently results in serious disasters. Previous research has focused on qualitatively evaluating slope buckling stability and rarely studied the whole process from bending deformation to forming landslide. In this work, considering the tensile and compressive characteristics of rock, the simulation of high and steep slope bucking failure evolved in Bawang Mountain, was conducted by numerical manifold method. The buckling deformation mechanism and progressive failure process of Bawang Mountain high steep slope were studied. The reliability of the numerical method was verified by the comparison of theoretical calculation and field measurement data. The results show that numerical manifold method can accurately simulate high and steep slope buckling failure process by preforming interlayer and cross joints. The process of slope buckling deformation and instability failure can be divided into minor sliding-creep deformation, interlayer dislocation-slight bending, traction by slope toe-sharp uplift, accelerated sliding-landslide formation. Under the long-term action of self-weight, the evolution of slope buckling from formation to landslide is a progressive failure process, which mainly contains three stages: slight bending deformation, intense uplift deformation and landslide formation.

Deep underground rocks exhibit significant layered heterogeneity due to geological evolution and sedimentation. Rock fracture toughness, as one of the important indicators of hydraulic crack propagation, also exhibits heterogeneous distribution. In order to investigate the influence of non-uniform fracture toughness of layered rocks on hydraulic crack propagation, this paper establishes a planar three-dimensional hydraulic crack propagation model. The model is numerically solved using the 3D displacement discontinuity method (3D-DDM) and the finite difference method. The calculation results indicate that when the distribution of the fracture toughness of layered rocks changes from uniform to non-uniform, the fracture morphology develops from a standard circular crack to an elliptical crack. When the difference of the rock fracture toughness between adjacent rock layers and the middle rock layer (pay zone) is large enough, the fracture morphology will develop towards a rectangular shape. In addition, when the fracture toughness of rock layers is non-uniformly distributed, the hydraulic crack not only rapidly expand in the softening layer (rock layer with lower fracture toughness), but also slowly propagate in the strong layer (rock layer with higher fracture toughness). However, the propagation speed in the softening layer is much faster than that in the strong layer. The results indicate that the heterogeneity of rock fracture toughness has an important impact on the morphology, propagation speed, and direction of hydraulic fractures.

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.