The effect of a gouge layer on rupture propagation along brittle shear fractures in deep and high-stress mines

Mngadi, Siyanda; Tsutsumi, Akito; Onoe, Yoshiko; Manzi, M.; Durrheim, Raymond; Yabe, Yasuo; Ogasawara, Hiroshi; Kaneki, Shunya; Wechsler, Neta; Ward, A. K.; Naoi, Makoto; Moriya, Hideshige; Nakatani, Masao

doi:10.1016/j.ijrmms.2020.104454

Cited by 6 publications

(3 citation statements)

References 49 publications

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“…In fact, incohesive fault rocks have a high potential for dilation and compaction under conditions of evolving the stress state. Although fault rocks often re‐gain cohesion during the interseismic periods at seismogenic depth (5–15 km), incohesive fault rocks are commonly observed at shallow depth (<5 km) where they can host earthquakes induced by human underground activities (e.g., quarry extraction, Ritz et al., 2020; deep gold mines; Mngadi et al., 2021) and tectonic earthquakes (e.g., Champenois et al., 2017; Kyriakopoulos, 2013; Thouvenot et al., 1998).…”

Section: Implications For Natural Faultsmentioning

confidence: 99%

The Influence of Loading Path on Fault Reactivation: A Laboratory Perspective

Giorgetti

Violay

2021

Geophysical Research Letters

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The loading path the fault experiences is often neglected when evaluating its potential for reactivation and the related seismic risk. However, stress history affects fault zone compaction and dilation, and thus its mechanics. Therefore, in incohesive fault cores that could dilate or compact, the role of the loading path could not be ruled out. Here we reproduce in the laboratory different tectonic loading paths for reverse (load-strengthening in the absence of significant fluid pressure increase) and normal gouge-bearing faults (load-weakening) to investigate the loading path influence on fault reactivation and seismic potential. We find that, before reactivation, experimental reverse faults undergo compaction, whereas experimental normal faults experience dilation. Additionally, when reactivated at comparable normal stress, normal faults are more prone to slip seismically than reverse faults. We infer that the higher mean stress normal faults experience compacts more efficiently the fault rock, increasing its stiffness and favoring seismic slip.Plain Language Summary Slip along pre-existing faults in the Earth's crust occurs whenever the shear stress resolved on the fault plane overcomes its frictional strength, potentially generating catastrophic earthquakes. The increase in the shear stress can follow different tectonic loading paths, and in particular, load-weakening versus. load-strengthening paths when it is coupled respectively to a decrease versus. an increase in the normal stress clamping the fault. The role of the loading path cannot be ruled out, especially in the presence of a thick, incohesive fault zone that can change its volume under different stress conditions. However, in most friction experiments, the fault is loaded under constant or increasing the normal stress, that is, load-strengthening. Here, we bridge the gap in laboratory loading paths simulating reactivation at the same normal stress clamping the fault but with different tectonic stress histories. Interestingly, our results suggest contrasting hydro-mechanical behavior for loadstrengthening versus. load-weakening path: (1) before reactivation, fault zone compaction versus. dilation and (2) when reactivated at comparable normal stress, stable creep versus seismic slip, respectively. Our study has only scratched the surface of the loading-path influence on thick fault stability and potential implications for fluid circulation in fault zones, stressing the importance of further investigating the loading path influence.

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Section: Implications For Natural Faultsmentioning

confidence: 99%

The Influence of Loading Path on Fault Reactivation: A Laboratory Perspective

Giorgetti

Violay

2021

Geophysical Research Letters

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“…Chen and Gong et al [23][24][25] used acoustic emission technology to unite RFPA software to simulate and analyze the failure process of deep rock joints, and revealed the failure mechanism of deep jointed rock mass during excavation. Mngadi and Nguyen et al [26,27] carried out friction experiments of different groups on rocks from deep mining in high-stress areas, and described the propagation process of the fracture along the underground brittle shear zone, which is of great significance to the study of rockburst. Li et al [28] studied the stress environment and conditions of various fault activation and think that mining would cause uneven changes in vertical stress and horizontal stress in the fault, which was easy to induce fault activation.…”

Section: Introductionmentioning

confidence: 99%

Research on Fault Activation and Its Influencing Factors on the Barrier Effect of Rock Mass Movement Induced by Mining

Guo

Luo

Wang³

2023

Applied Sciences

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For the study of the driving forces behind fault activation and its influencing factors on the barrier effect of rock mass movement under the influence of mining, the discrete element numerical simulation software 3DEC was used for the analysis of the impact on the distance to mining area from fault, the buried depth of the upper boundary of the fault, the dip angle of fault, the size of the mining area and the thickness of the fault zone respectively. The results show that the mining areas are closer to the fault as distances decrease, the burial depth of the upper boundary of the fault increases, and the size of the mining area increases, the fault is easier to activate, and fault activation has a stronger barrier impact on displacement field and stress field propagation. When the fault is cut into the goaf, the difference of rock displacement in both directions of the fault increases when the dip of the fault increases, and the fault is more susceptible to instability and activation. The barrier strength grows with the increase of the thickness of the fault fracture zone. The results of this study have important implications for the guard against and control of deep mining-related fault activation disasters.

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“…In order to study the effect of fault gouge on fault block slip stability, some researchers conducted shear tests using fault gouge of different materials, shapes, thicknesses, and humidity conditions [28][29][30][31][32][33] and observed the changes in the thickness, composition, porosity, and microstructure of the gouge [34][35][36][37][38]. It is found that the faults could be weakened by fault gouge when the seismic slip rate is 0.1-10 m/s, independent of the During the test, samples of the same batch were used to eliminate the differences in composition and grain size between rocks.…”

Section: Introductionmentioning

confidence: 99%

Roles of Normal Stress, Roughness, and Slip Displacement in the Stability of Laboratory Fault in a Sandstone

Sun

et al. 2022

Applied Sciences

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Unstable slip of a fault block is considered to be the main cause of shallow earthquakes. However, the underlying mechanism of the stability-to-instability transition of faults has not been fully understood. Here, we used the stiffness ratio, which is the ratio between the shear stiffness of the fault subjected to direct shear and the critical stiffness to evaluate the fault stability degree from stable to unstable slip, and examined the effects of normal stress, roughness, and slip displacement on the fault stability. Our experimental results show that with the increase in slip displacement, the shear stiffness change in stable slip mainly includes four stages, namely “rapid increase–keep unchanged–slow increase–rapid decrease”, and unstable slip tends to occur in the last two stages. This process of shear stiffness change is accelerated by the increase in normal stress and the decrease in fault roughness. Our study reveals that fault stability over slip is mutually dictated by asperity interlocking and wear-induced gouge. Asperity interlocking controls fault stability when the gouge amount is low, whereas the fault gouge prevails with the increased wear of the fault surface since the gouge generated during slip can participate in the subsequent friction process. Thus, we infer that the stable–unstable transition of fault over slip is a spontaneous process due to the interplay of asperity interlocking and wear-induced gouge lubrication.

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The effect of a gouge layer on rupture propagation along brittle shear fractures in deep and high-stress mines

Cited by 6 publications

References 49 publications

The Influence of Loading Path on Fault Reactivation: A Laboratory Perspective

The Influence of Loading Path on Fault Reactivation: A Laboratory Perspective

Research on Fault Activation and Its Influencing Factors on the Barrier Effect of Rock Mass Movement Induced by Mining

Roles of Normal Stress, Roughness, and Slip Displacement in the Stability of Laboratory Fault in a Sandstone

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