An analysis of thixotropic micropore variation and its mechanism in loess

The risk assessment of rockburst intensity is significant for tunnel construction safety. First, the depth of the rockburst (X1), the uniaxial compressive strength of the rocks (X2), the brittleness coefficient of the rocks (X3), the stress coefficients of the rocks (X4), and the elastic energy index (X5) are adopted as the evidence body, and their essential certainty and reliability is determined using the entropy-gray correlation theory. Second, the synthetic certainty reliability of other samples is calculated based on the evidence theory. Relatively to the traditional gray extension model, it can improve the predictive accuracy and determine the certainty and reliability of different evidence bodies. The difference of importance between other evidence bodies can be reflected; and an interval scale can be taken into consideration in the evaluation process, so the proposed theory can reasonably predict the grade criterion which is interval form. Conclusion demonstrated that the suggested approach is entirely consistent with the actual investigation. The proposed model not only considers the unreliability or reliability of the problem but also solves some degrees of uncertainty and ambiguity of the datum; it enhances the predictive efficiency and provides a new way and thought for future risk assessment of rockburst intensity.

“…4 into Eq. 5, the reliability of the classification limits of the indexes M is obtained as follows (Gu et al, 2022;Wang et al, 2023a;Wei et al, 2023):…”

Section: The Construction Of Assessment Systemsmentioning

confidence: 99%

The application of evidence-entropy weight gray incidence theory on the risk assessment of rockburst intensity in the Daxiangling tunnel

Zhang,

2023

“…With the exploitation of large quantities of coal resources, shallow coal resources seem to have been exhausted gradually, such that the current coal mining situation in China has shifted from shallow to deep mining (Wang et al, 2023a;Zheng et al, 2024a;Yongjiang et al, 2024). During actual coal mining, the balance of the space material environment of the underground system is destroyed, which may lead to various geological disasters (Wei et al, 2023;Zheng et al, 2024b;Pengshuai et al, 2024). The overall safety of coal mine production is also greatly threatened by water damage (Wang et al, 2023b;Wang et al, 2023c;Xue et al, 2024).…”

Section: Introductionmentioning

confidence: 99%

Study on overburden failure characteristics and displacement rule under the influence of deep faults

Zhang,

Wu,

Cao

et al. 2024

Deep faults significantly impact the structural stabilities and deformation behaviors of their overburden rocks, which are key factors in underground engineering and geological hazard research. Considering the problem of deep-fault-overburdened breaking during mining of super-thick coal seams and taking the Yaoqiao Coal Mine as the research object, the mining fracture evolution characteristics and overburden displacement law of the non-structured and fault-bearing overburden corresponding to fully mechanized caving mining are compared and analyzed using numerical simulations and physical similarity simulations. The results of this study show the following: 1) The fracture height of the overlying rock presents a specific change law with advancement of the working face; the initial rapid increase to a maximum height of 74 m is achieved when the working face advances to 90 m; with the development of the plastic zone indicating past yield, the fracture height decreases to 54 m and becomes stable, and the final caving angle of the fracture stabilizes at 70°. 2) In coal mining under normal fault conditions, when the working face advances from the upper to lower walls, the roof forms a masonry beam structure that slows down fault activation and crack development. When moving away from the fault, the overburden movements and water-conducting cracks are fewer, and the crack height is lower than that without faults. When approaching the fault, the influence of the faults in the fracture zone increases, and the height of fracture development reaches the maximum value after crossing the fault, highlighting the significant influence of the fault on fracture development. 3) Through a similarity simulation test, it is shown that the overburden caving zone is further compacted by the overburden rock and that the roof collapses in a large range, resulting in rapid upward development of the overburden rock cracks and separation of the central overburden rock cracks that are gradually compacted and closed. These findings are expected to have important theoretical and practical significance for deep underground engineering design, geological disaster prevention, and fault activity monitoring.

“…For reservoir landslides caused by reservoir impoundment, one of the most important ways to prevent and mitigate them is to obtain their initiation and movement processes through certain monitoring means, and elaborate their deformation, damage mechanisms and potential destabilization possibilities, so as to provide basis for the management and administration of landslide hazards (Tang et al, 2019;Cao et al, 2021;Wang et al, 2023a;Wang et al, 2023b;Wei et al, 2023). Up to date, a large number of researchers have studied the initiation and movement process of reservoir landslides (Gutiérrez et al, 2015;Kaczmarek et al, 2015;Gu et al, 2017;Wang et al, 2021;Chen et al, 2022;Wu et al, 2022), and the results show that the deformation characteristics of reservoir landslides can be mainly divided into four stages: the stabilization period before impoundment, the large deformation and destabilization at the time of the first impoundment, the cyclic deformation caused by the rise and fall of the water level during the operation of the reservoir, and the overall destabilization and destruction of the landslides.…”

Section: Introductionmentioning

confidence: 99%

Reservoir landslide monitoring and mechanism analysis based on UAV photogrammetry and sub-pixel offset tracking: a case study of Wulipo landslide

Li,

Jiang,

Shi

et al. 2024

Introduction: Reservoir landslides undergo large deformations during the early stages of impoundment and maintain long-term persistent deformations during the operational period of the reservoir. The management of reservoir landslides mostly focuses on the early identification, risk assessment during the large deformations, and long-sequence monitoring during long-term persistent deformations, which requires sufficient continuity and integrity of the landslide monitoring data.Methods: Taking the Wulipo (WLP) landslide in Baihetan Reservoir as example, this paper proposes a reservoir landslide monitoring method that integrates field survey, unmanned aerial vehicle (UAV) photogrammetry and global navigation satellite system (GNSS) monitoring, which can effectively eliminate the practical monitoring gaps between multiple monitoring methods and improve the continuity and completeness of monitoring data.Results and discussion: First, this study determined the initiation time of the landslide through the field investigation and collected five period of UAV data to analyze the overall displacement vector of the WLP landslide using sub-pixel offset tracking (SPOT). On the basis of the above data, we compensated for the missing data in GNSS system due to the practical monitoring vacancies by combining the field survey and the landslide-water level relationship. Based on these monitoring data, this paper points out that the WLP landslide is a buoyancy-driven landslide, and whether or not accelerated deformation will occur is related to the maximum reservoir water level. Finally, this study analyzed and discussed the applicability of UAV photogrammetry for reservoir landslide monitoring in the absence of ground control points (GCPs), and concluded that this method can be quickly and flexibly applied to the stage of large deformation of reservoir landslides.