Research on Control Mechanism of Surrounding Rock of Deep Gob-Side Entry Retaining

Abstract

To address the large deformation of the surrounding rock of deep gob-side entry retaining under high stress, lithological characteristics of the surrounding rock and failure model of support body and their evolutionary processes are analyzed through field investigation and theoretical analysis. Failure mechanisms of surrounding rock and the technology to control it are studied systematically. The results show that the causes of the large deformation of the surrounding rock are weak thick mudstones with softening property and water absorption behavior, as well as its fragmentation, dilatancy, and long-term creep during strong disturbance and highly centralized stress states. The cross-section shape of the roadway after deformation and failure of the surrounding rock is obviously asymmetric in both the horizontal and vertical directions. Since the original system supporting the surrounding rock is unable to completely bear the load, each part of the supporting system is destroyed one after the other. The failure sequences of the surrounding rock are as follows: (1) roadway roof fracture in the filling area, (2) filling body fracture under eccentric load, (3) rapid subsidence of the roadway roof, and (4) external crack drum and rib spalling at the solid coal side. Due to this failure sequence, the entire surrounding rock becomes unstable. A partitioned coupling support and a quaternity control technology to support the surrounding rock are proposed, in which the roof of the filling area plays a key role. The technology can improve the overall stability of gob-side entry retaining, prevent support structure instability caused by local failure of the surrounding rock, and ensure the safety and smoothness of roadways.

Study on the gas outburst control effect of goaf on the neighboring working face: Case study of Pingmei No.4 Mine

“…7 Goaf-side entry driving can effectively reduce coal loss and reduce the gas management cost of the working face adjacent to goaf, which is one of the important means for the sustainable development of coal resources at present. [13][14][15][16] Mining pressure theory shows that, under the influence of mining operation, the roof stress will be redistributed. 17 From the free surface to the inside, it is pressure unloading zone, stress concentration zone, and original rock stress zone in order, and the risk of coal outburst within the pressure relief zone has been eliminated.…”

“…Goaf‐side entry driving can effectively reduce coal loss and reduce the gas management cost of the working face adjacent to goaf, which is one of the important means for the sustainable development of coal resources at present 13–16 . Mining pressure theory shows that, under the influence of mining operation, the roof stress will be redistributed 17 .…”

Dynamic Pressure Manifestation Mechanism and Control Techniques for Roadways with Large Mining Heights and Intense Mining: A Case Study

“…Xiong et al [12] studied the cyclic failure mechanism of inclined roadways and revealed the principle of roadway deformation control. Through a study on the large deformation mechanism in soft rock roadways, Liu et al [13] analysed the failure sequence of the surrounding rock and proposed the zoned coupling support technique. Li et al [14] studied the rib spalling mechanism in deep soft coal roadways and analysed the relationship between coal wall spalling and the mechanical properties of the coal and the rock.…”