深部充填开采留巷围岩偏应力演化规律与控制

Deviatoric stress evolution laws and control of surrounding rock at gob-side entry retaining in deep backfilling mining

  • 摘要: 针对深部充填开采留巷围岩控制难题,以邢东矿1126运料巷为研究背景,采用应变软化模型研究工作面推进全过程中留巷围岩偏应力与塑性区演化规律。研究表明:(1)超前采动影响较明显区顶板约为32 m,底板和两帮均约为16 m,留巷采动影响较明显区顶板约为32 m,底板约为24 m;(2)从工作面回采开始到工作面回采结束的全过程对留巷围岩偏应力和塑性区进行监测得到:偏应力分布形态以瘦高椭圆状→近似圆状→小半圆拱→大半圆拱→扇形拱进行演化,偏应力峰值带以顶底板→顶底帮角(实体煤侧)和实体煤帮进行转移;塑性区分布形态以近似椭圆状→近似圆状→半球状进行演化,且塑性区呈非对称分布;(3)基于深部充填开采留巷围岩偏应力和塑性区非对称分布特征,提出了分区非对称围岩控制技术,实践表明,留巷围岩控制效果明显。

     

    Abstract: In order to solve the surrounding rock control problems of gob-side entry retaining in deep backfill mining, taking the No. 1126 haulage roadway in Xingdong coal mine as an example,the Strain Softening model was adopted to simulate the deviatoric stress and plastic zone evolution laws of the surrounding rock at the gob-side entry retaining during the whole process of advancing with the working face. The results show that ① the more obvious influence zone of the advanced mining about is 32 m on the roof,but about 16 m on floor and two ribs. The more obvious influence range of the lag mining about is 32 m on the roof,but about 24 m on floor. ② The monitoring sections are monitored from the beginning to the end of working face mining during the whole process of advancing with the working face. It is concluded that the evolutional sequence of deviatoric stress distribution form is thin elliptical shape,approximate circle shape,small semicircle arch,large semicircle arch,and fantail arch. The peak value zone of deviatoric stress is trans- ferred from the roof-to-floor to the corner of roof and floor in solid coal side and the solid coal side. Meanwhile,the or- der of plastic zone evolution state of the surrounding rock of the gob-side entry retaining as follow:Approximate elliptical shape,approximate circle shape,hemisphere shape,the plastic zone of the surrounding rock is asymmetric distribu- tion. ③ Based on the asymmetric distribution characteristics of deviatoric stress and plastic zone in gob-side entry re- taining with deep backfilling mining,the asymmetric control technology of surrounding rock in areas was proposed and applied in the field test. The surrounding rock deformation of gob-side entry was effectively controlled.

     

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