A Case Study on Large Deformation Failure Mechanism and Control Techniques for Soft Rock Roadways in Tectonic Stress Areas

Abstract

Large deformation and failure of soft rock are pressing problems in the mining practice. This paper provides a case study on failure mechanisms and support approaches for a water-rich soft rock roadway in tectonic stress areas of the Wangzhuang coal mine, China. Mechanic properties of rock mass related to the roadway are calibrated via a geological strength index method (GSI), based on which a corresponding numerical simulation model is established in the Universal Discrete Element Code (UDEC) software. The failure mechanism of the roadway under water-saturating and weathering conditions is revealed by field tests and numerical simulation. It is found that the stress evolution and crack development are affected by weathering and horizontal tectonic stresses. The roadway roof and floor suffer from high stress concentration and continuous cracking, and are consequently seen with rock failure, strength weakening, and pressure relief. Unfortunately, the current support system fails to restrain rock weathering and strength weakening, and the roadway is found with serious floor heave, roof subsidence, and large asymmetric deformation. Accordingly, a new combined support system of “bolt–cable–mesh–shotcrete + grouting” is proposed. Moreover, numerical simulation and field testing are conducted to validate the feasibility and effectiveness of the proposed approach, the results of which demonstrate the capacity of the proposed new support method to perfectly control the surrounding rock. Findings of this research can provide valuable references for support engineering in the soft rock roadway under analogous geological conditions.

Experimental investigation, binary modelling and artificial neural network prediction of surfactant adsorption for enhanced oil recovery application

“…Three main peaks were observed at 20.84◦, 26.63◦ and 50.12◦, then they were compared to JCPDS record which indicated the high quartz presence in the sample. The other minor peaks indicated the low quantity presence of quartz, kaolinite, illite and Illite-Smectite [67] , [68] . A semi-quantitative mineral composition of the crushed rock is depicted in Table 1 .…”

Combined support technology for main roadway passing through goaf: A case study

“…In contrast, the siltstone is an unstable rock stratum because of its relatively small strength and thickness. Accordingly, the roof siltstone can be used to analyze the reducing span control mechanism of the reinforced concrete pillar 61,62 . A mechanical model was constructed for the roof rock beam under the reducing span control of the reinforced concrete pillars based on the structural characteristics of the goaf roof.…”

“…Accordingly, the roof siltstone can be used to analyze the reducing span control mechanism of the reinforced concrete pillar. 61,62 A mechanical model was constructed for the roof rock beam under the reducing span control of the reinforced concrete pillars based on the structural characteristics of the goaf roof. To simplify the model and facilitate its calculation, the following assumptions were made.…”

Analysis of Stress and Deformation Characteristics of Deep‐Buried Phyllite Tunnel Structure under Different Cross‐Section Forms and Initial Support Parameters

“…In view of the problems in the construction of soft rock tunnels, many studies based on on-site monitoring have been carried out [1][2][3][4][5]. e stability of the soft rock tunnel is affected by the structure, strength, and groundwater conditions of the surrounding rock [6][7][8].…”