充填开采的协作支撑系统及其力学特征

针对"三下"煤炭充填开采引起的岩层移动与控制问题,根据充填开采特点,重点考虑充填体、煤柱和承重岩层的共同协调作用,提出"充填体+煤柱+承重岩层"协作支撑系统这一概念。运用岩石力学、围岩控制原理及其相关理论分别分析充填体的支护作用机制、煤柱的支撑条件、协作支撑系统的力学作用过程及稳定条件,研究结果表明:充填体的支护作用体现在对煤柱的侧向加固和对承重岩层的竖向支撑;充填体对煤柱的侧向应力应满足一定条件才能保证煤柱对上覆岩层产生较大的支撑力;"充填体+煤柱+承重岩层"协作支撑系统的力学作用过程分别经历了上覆岩层的加速下沉、加速或匀速下沉、减速下沉、平稳这4个主要阶段,分析得到"充填体+煤柱+承重岩层"协作支撑系统的稳定条件,并发现充填体的压实度和充填率越大,对形成和提高"充填体+煤柱+承重岩层"协作控制体系的整体性、改善受力环境就越有利,最终能最大限度地控制岩层移动及地表沉降。最后,将"充填体+煤柱+承重岩层"协作支撑系统理论应用于周源山煤矿的"三下"充填开采当中,结果表明,在进行充填设计时,至少应将充填体的压实度Dr提高到0.8以上,充填率Ff控制在90%以上,才能将地表沉降控制到最小值,该结果与数值计算结果较为接近。

COORDINATION SUPPORT SYSTEMS IN MINING WITH FILLING AND MECHANICAL BEHAVIOR

Aiming at subject of strata movement and control caused by the mining with filling under buildings,railways and water-bodies(three-underground),achieving together action of backfilling,coal pillar and roof load-bearing rock stratum was emphasized,and the conception of coordination support systems is put forward.Rock mechanics,strata control principle and others correlation theory are applied to analyze the supporting mechanism of backfilling,the supporting conditions of coal pillar and the process of mechanics action and the stability condition of the coordination support systems.Research shows that the supporting mechanism of backfilling act as the horizontal reinforce action at coal pillar and the vertical supporting action at roof load-bearing rock stratum;the horizontal reinforce action should meet the controlled condition for the purpose of greater holding power which coal pillar effect on overburden;The mechanics action of the coordination support systems with backfilling,coal pillar and roof load-bearing rock stratum experience four main stages including the accelerated subside of overburden,uniform speed subside,decelerated subside and steady in proper order.Moreover,it is found that the degree of compaction(Dr) and the packing fraction(Ff) bigger,these have more advantageous to integrity and bearing strength environment of the coordination support systems,and strata movement and ground subsidence can control as much as possible.At last,the coordination support systems theory is applied in the three-underground mining with filling of Zhouyuanshan mine.In order to reduce ground subsidence as much as possible,analytic result indicated that the degree of compaction(Dr) of backfilling raise to above 0.8,and the packing fraction(Ff) control above 90%.