上下盘开采顺序对断层煤柱采动应力的影响

Influence of mining sequence of hanging wall and foot wall on mining-induced stress of fault coal pillar

回采巷道沿断层边界布置时,采用基本顶断裂岩块铰接平衡理论研究了先采断层上盘或先采断层下盘2种开采顺序下,工作面采空区基本顶荷载在断层两侧的传递规律和差异性;现场实测了2种条件下断层煤柱及相邻回采巷道的矿压显现特征。研究表明:断层上盘先行开采时,断层的载荷传递系数较大,上盘断层煤柱压力小,下盘煤体压力较大。断层下盘先行开采时,断层的载荷传递系数与断层角度有关,当断层角度较大时,下盘采空区覆岩载荷可以传递给断层上盘,下盘断层煤柱压力小,上盘断层煤体压力大;当断层角度较小时下盘覆岩载荷难以传递给断层上盘,下盘断层煤柱压力较大,上盘煤体压力相对较小。为此,断层上、下盘开采顺序不同时应留设不同的断层煤柱。

The laws and differences of the load transmission of the basic roof over the gob area of the fault＇s two sides have been studied under the condition of different mining sequence of hanging wall and foot wall, based on the articulated balance theory of the fracture rock mass, with the roadway being arranged along the boundary of the fault. And the characteristics of ground pressure of fault coal pillar and the mining gateway nearby have been studied with the method of field test. The study has shown that the load transmitting coefficient of fault is relatively higher, the hanging wall of coal pillar abutment pressure is low and that the foot wall coal pressure is relatively higher when the hanging wall of fault is firstly mined. However, the load of transmitting coefficient of fault is related with the angle of fault when the foot wall is firstly mined. When the angle of fault is larger, the load of the gob area overlying strata can be transmitted to the hanging wall, so the foot wall of coal pillar abutment pressure is low and the hanging wall coal pressure is higher; while the angle of fault is smaller, the load of the gob area overlying strata can hardly be transmitted to the hanging wall, so the foot wall of coal pillar pressure is higher and the hanging wall coal pressure is relatively lower. Therefore, different widths of the fault coal pillar should be considered according to different mining sequences.