Compensation excavation method control for large deformation disaster of mountain soft rock tunnel

He, Manchao; Sui, Qiru; Li, Mengnan; Wang, Zhijiao; Tao, Zhigang

doi:10.1016/j.ijmst.2022.08.004

Cited by 91 publications

(27 citation statements)

References 30 publications

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“…The fractures are gradually closed under effective stress, and the coal seam permeability is decreased [37][38][39]. In the stable gas production stage and declining gas production stage, due to the matrix shrinkage effect, the fracture width and coal seam permeability both increase [40][41][42].…”

Section: Gas-expanding Fracturesmentioning

confidence: 99%

A New Mode of Visible Fracture System in Coal Seams and Its Implications for Coalbed Methane Seepage

Jin

Wang

et al. 2023

Geofluids

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As the central flow channel for fluid seepage through rock layers, the visible fracture system (VFS) significantly affects geoenergy extraction for petroleum, natural gas, geothermal resources, and greenhouse gas sequestration. In this work, we propose a new mode of VFS in coal seams, including hydraulic fractures, exogenetic fractures, interlayer fractures, gas-expanding fractures, and cleats. The development characteristics of VFSs in coal seams are analyzed, including containing their geometry, orientation, scale, distribution, and connection between each other. Furthermore, the implications of the VFS for fluid (gas and water) and solid (coal fines) flow through coal seams are discussed. The development of the VFS determines the effective flow conductivity, affecting the flow of gas, water, and coal fines. Additionally, as the reservoir pressure transfer channel, the VFS significantly influences depressurization with reservoir depletion, determining the extension of the methane desorption range. The exogenetic fractures and interlayer fractures dominate the expansion of the primary hydraulic fractures, and gas-expanding and cleats usually control the branch of hydraulic fractures. Furthermore, we find that the daily production rate distribution of most CBM wells presents a particular banded, L-shaped, or T-shaped pattern. It is thought that the VFS dominates the productivity of CBM in coal seams. The field production data also provide evidence that the occurrence of the VFS makes the CBM reservoir heterogeneous. This study presents a recommended framework involving the characteristics of the VFS and its influences on CBM production.

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Section: Gas-expanding Fracturesmentioning

confidence: 99%

A New Mode of Visible Fracture System in Coal Seams and Its Implications for Coalbed Methane Seepage

Jin

Wang

et al. 2023

Geofluids

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“…Some scholars analyzed the characteristics of slope rock mass slabbing under different stress modes caused by valley undercutting, excavation, and long-term geological processes from the perspective of supergene transformation and aging deformation (Huang et al, 1994;Tao et al, 2000;Huang, 2008;Huang et al, 2017;Cai et al, 2019;Liang et al, 2022;Li et al, 2022b). The latest research show that a large number of slabbing failures have also emerged in the excavation of underground chambers and tunnels (Du et al, 2016;Gong et al, 2018Gong et al, , 2020Pan et al, 2020;Jiang et al, 2021;He et al, 2022;Tang et al, 2022;Wang et al, 2022). Huang (2008) and Huang et al (2017) proposed the three stages of the development process of high slope and the characteristics of slope stress field with undercutting or excavation unloading, which is of great significance to reveal the causes of rock mass slabbing under stress conditions at different development stages of the slope and also deepen the understanding of rock mass slabbing phenomena exposed by the excavation of deep tunnels and hydropower underground chambers.…”

Section: Introductionmentioning

confidence: 99%

Mechanical mechanism of rock mass slabbing aggravating toppling failure

Cai

Lu²,

Li³

et al. 2023

Front. Ecol. Evol.

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Many slabbing rock masses have emerged in hydropower slopes and underground engineering, with the construction of basic engineering and resource development projects along the zone of the Belt and Road. The anti-dip slabbing rock mass is prone to toppling and the degree of slabbing controls the development of toppling deformation. There are a few reports on the mechanical mechanism of rock mass toppling deformation after slabbing. Based on the analysis of the genetic conditions of rock mass slabbing, the influence of rock mass after slabbing on toppling deformation was explored by means of the mechanics method. The toppling bending deflection (TBD) and the toppling fracture depth (TFD) were selected as the analysis indexes, and the response regularity of slabbing on toppling rock mass was analyzed with examples. The results show that the width and thickness of the slabbing rock mass become narrower and thinner, the toppling bending deflection (TBD) increases, the toppling fracture depth (TFD) decreases, and the toppling deformation and failure intensify. The TBD is independent of the width of rock mass slabbing under self-weight, and the change of TBD is slow when the slab beam slabbing number (n) of thickness is <4 and fast when the slabbing number is above 4. The first TFD decreases fast when w is <2.0 m and it tends to be stable when w is above 2.0 m. The first TFD reduces relatively fast with the decrease in the thickness (t) of the slab beam. The result of this study can provide a reference for the treatment and evaluation of slabbing rock mass toppling deformation.

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“…Southwest China is a region where landslide geological disasters occur frequently, and the analysis of the deformation characteristics of landslides is one of the essential aspects of landslide control (Bao et al, 2023). Especially when encountering complex geological conditions such as broken structural surface, weak interlayer and fault, the stability of landslide is greatly reduced (Wang et., 2022a;Wang et., 2022b;He et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Analysis of displacement evolution characteristics of reverse-dip layered rock slope based on geological geometric partition

Zhang

Teng

et al. 2023

Front. Earth Sci.

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To investigate the toppling displacement evolution characteristics of anti-dip rock slopes, the Xiaodongcao-Zhengjiadagou bank slope is taken as an engineering case, and firstly, the geological geometric distribution characteristics of the slope are obtained by superimposing the lithology, slope, and elevation raster layers of the slope through ArcGIS, and the geological partition with the largest area is the Lower Triassic Daye Formation, bottom elevation, and medium slope; based on the actual surface displacement monitoring data, the spatio-temporal evolution nephogram of toppling displacement of bank slope every half year is interpolated by Inverse Distance Weight method, and then the last displacement nephogram is assigned to the thousandth and superimposed with the geological geometric partition to obtain the displacement superposition characteristics. The results show that: the obvious zone of horizontal displacement deformation mainly occurs in the front and middle of the bank slope, mainly shear deformation, vertical displacement is primarily in the front and the back edge of the bank slope and the total displacement deformation is more similar to the horizontal displacement; the horizontal displacement value is larger than the vertical displacement value, the horizontal displacement deformation controls the overall deformation of the bank slope; through the analysis of the geometric superposition evolution of the anti-dip rock slope, the displacement superposition strong deformation zone is located at the boundary between the Triassic Jialingjiang Formation (T1j) and the Triassic Daye Formation (T1d).

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Compensation excavation method control for large deformation disaster of mountain soft rock tunnel

Cited by 91 publications

References 30 publications

A New Mode of Visible Fracture System in Coal Seams and Its Implications for Coalbed Methane Seepage

A New Mode of Visible Fracture System in Coal Seams and Its Implications for Coalbed Methane Seepage

Mechanical mechanism of rock mass slabbing aggravating toppling failure

Analysis of displacement evolution characteristics of reverse-dip layered rock slope based on geological geometric partition

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