Abstract
To solve the control problem of the surrounding rock of gob-side entry retaining under typical roof conditions in deep mines, we conduct theoretical analysis, numerical simulation, and actual measurements. Starting from the plastic zone of the surrounding rock, the serious damage area, the degree and scope of damage, and the dynamic evolution process of the surrounding rock of the gob-side entry retaining are systematically analyzed under four typical roof conditions in deep mines; the expansion and evolution laws of the plastic zone of the surrounding rock are expounded; and a key control technology is proposed. The results indicate that (1) the plastic failure of surrounding rock was concentrated mainly on the coal side and on the floor, especially in the filling body. The plastic zone of the surrounding rock of the gob-side entry retaining with the thick immediate roof was widely distributed and deep, but the plastic failure of the filling body was not obvious. The plastic failure of the surrounding rock of the gob-side entry retaining with the compound roof was mainly concentrated on the roof, filling body, and floor of the filling area. (2) According to the typical roof conditions of the deep gob-side entry retaining, the order of the degree of damage to the surrounding rock was as follows: thick immediate roof, compound roof, thin immediate roof, and thick-hard roof. (3) A “multisupport structure” control system is proposed for the gob-side entry retaining in a deep mine, including measures for enhancing the bearing performance of the anchorage system, increasing the strength of the cataclastic coal-rock mass, enhancing the bearing capacity of the filling body, and increasing the bearing capacity on the tunnel side. The proposed technology was applied to the deep gob-side entry retaining project in the east area of Panyi Mine, and it effectively fulfilled the reuse requirements of gob-side entry retaining in deep mines.
Highlights
As shallow coal resources are depleted, coal mines will gradually transition to the mining of deep coal resources in China [1,2,3]
(3) A “multisupport structure” control system is proposed for the gob-side entry retaining in a deep mine, including measures for enhancing the bearing performance of the anchorage system, increasing the strength of the cataclastic coal-rock mass, enhancing the bearing capacity of the filling body, and increasing the bearing capacity on the tunnel side. e proposed technology was applied to the deep gob-side entry retaining project in the east area of Panyi Mine, and it effectively fulfilled the reuse requirements of gob-side entry retaining in deep mines
By using the conformal mapping function theory, Lu et al [25] determined the shape and size of the plastic zone of the surrounding rock of a circular roadway under nonhydrostatic stress; the results indicated that the plastic zone was elliptical, and its long axis was oriented along the direction of the minimum in situ stress
Summary
As shallow coal resources are depleted, coal mines will gradually transition to the mining of deep coal resources in China [1,2,3]. Liu et al [11, 12] studied the size, angle, and distribution characteristics of the plastic zone of the rock surrounding the gob-side entry retaining, obtained a variation law of the main stress and expansion characteristics of the plastic zone, and clarified the reasons for asymmetric deformation of the surrounding rock. The space-time evolution law of the plastic zone of the surrounding rock of a gob-side entry retaining in a deep mine is studied by combining theoretical analysis, numerical simulation, and field measurement. Considering the actual conditions in operational mines, a partition control technology for the surrounding rock of the gob-side entry retaining in a deep well is proposed to solve the challenges that arise due to the continuous development of and changes in surrounding rock failure in various disturbed areas
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