Study on the law mining stress evolution and fault activation under the influence of normal fault

Abstract

Using the FLAC 3D numerical simulation method, the characteristics of mining stress evolution, fault activation patterns, and fault energy evolution characteristics are simulated and analyzed in the process of the footwall and hanging wall working face heading to a normal fault. The study shows that the fault cut off the mining stress propagation of overlying strata, and the stress blocking effect due to the fault is evident. When working faces head towards a fault, the abutment pressure and the vertical stress of the surrounding rock increase first and subsequently decrease. The abutment pressure of the coal wall and fault is highest when the distances to the fault are 40 m and 30 m for the footwall and hanging wall working faces, respectively. Moreover, the hanging wall mining stress is higher than the footwall mining stress. Fault activation in high-located strata precedes that in low-located strata when working faces head towards the normal fault. Energy is gradually accumulated before unstable fault events take place because of mining, and fault instability quickly releases a lot of energy. The mining stress concentration and fault activation due to faults easily result in rock bursts and mine seismicity. ARTICLE INFO

Shear Mechanical Behaviours and Multistrength Parameter Characteristics of Fault Gouge

“…e fault gouge's dry density is 1.97 to 2.11 g/cm 3 , which is obviously different for the different colored gouges and is much higher than that of common soils. However, the particle specific gravity is very close, which is 2.66 to 2.69 g/cm 3 . e particle size distribution curves and cumulative grading curves of the different fault gouges (Figure 7) were obtained by using a Bettersize-2000 laser particle size analyzer.…”

“…As one of the most important weak zones in rock mass, fault zone is a basic condition that controls engineering safety in mountain areas [1][2][3]. Studies on fault gouges' shear properties are helpful in explaining and predicting disaster risk in fault crossing areas [4].…”

Coal Pillar Width Design in High - stress Gob - side Entry Driving

“…Li et al developed a numerical model using FLAC3D code for investigating two cases of yield pillar application in Chinese mines, in which double-yielding models were adopted for simulating gob materials [28]. Cheng et al built a 3D simulation model using FLAC3D code for the design of coal pillars in an inclined thick coal seam [29]. In addition, as coal yield continuously increases, numerous scholars have conducted a large number of theoretical analyses of deformation failure mechanism and deformation control of gob-side entry and proposed large and small structural stability principles in fully mechanized gob-side entry driving and calculation formulas of lateral supporting pressure peak position.…”

Overlying strata movement and stress evolution laws triggered by fault structures in backfilling longwall face with deep depth

“…It is believed that the redistribution of stress caused by mining activities leads to significant deformation around the fault. By studying the influence of faults on mining stress and the slipping law of overburden during the fault crossing process, the fault in the high stratum are activated in preference to the lower stratum, and the energy gradually accumulates and then the longwall face advances to the fault, rockburst and impact pressure are easily induced by activation fault (Wang et al 2012;Jiang et al 2015;Li et al 2015;Jiao et al 2017;Wu et al 2017). and Zhang et al (2018) analyzed the overburden movement at the process of longwall face in through the giant thrust fault, and obtained the stress variation law of fault plane based on the principle of instability and fault activation coupling of overburden space structure.…”