缓倾斜煤层斜梯形巷道沿空煤柱宽度及围岩控制研究

Study on coal pillar width and surrounding rock control of inclined trapezoidal roadway in gently inclined coal seam

为探究缓倾斜煤层斜梯形沿空巷道煤柱留设尺寸合理值和留巷围岩控制技术,以任楼煤矿72510N工作面为工程背景,应用考虑煤层倾角的内外应力场理论、数值模拟和现场试验展开研究。理论计算确定72510N工作面内应力场的宽度为13.4 m,煤柱尺寸合理值应不大于8.4 m,结合模拟计算结果确定煤柱尺寸合理值为7 m。在分析控制缓倾斜煤层斜梯形沿空掘巷围岩变形难点的基础上,结合研究结果,提出采用非对称支护对围岩进行控制,支护方式为“高强锚杆+顶板高强长锚索+煤柱帮斜拉锚索+锚网”,并在现场进行了应用。现场试验结果表明,煤柱留设尺寸7 m及采用非对称支护技术沿空巷道围岩大变形可得到有效控制,实测顶板右中、顶板左中、煤柱、实体煤和底板测点在掘进期间观测最大位移量分别为121,105,96,90,82 mm,回采期间观测最大位移量分别为389,363,346,335,325 mm,满足了现场生产需求。

To explore the reasonable size of inclined trapezoidal gob side entry pillar in gently inclined coal seams and the control technology of roadway surrounding rock,taking the 72510N working face as the engineering background,the internal and external stress field theory,numerical simulation and field test considering the coal seam dip angle are applied to carry out research.Through theoretical calculation,it was determined that the width of the stress field in the 72510N working face is 13.4 m,and the coal pillar reasonable width should not exceed 8.4 m.Combining with the simulation calculation results,the coal pillar width was determined to be 7 m.On the basis of analyzing the difficulties in controlling the deformation of surrounding rock of inclined trapezoidal gob side entry in gently inclined coal seams,combining with the research results,asymmetric support was used to control the surrounding rock.The support mode of“high-strength anchor bolt+roof high-strength long anchor cable+pillar side inclined anchor cable+anchor mesh”was applied,and the field test results showed that the large deformation of surrounding rock of roadway along goaf was controlled by setting a 7 m coal pillar and using asymmetric supporting.The maximum displacements of the right middle roof,the left middle roof,the coal pillar,the solid coal and the floor measuring points during tunneling were 121,105,96,90 and 82 mm,respectively,and the maximum displacements observed during mining were 389,363,346,335 and 325 mm,respectively,meeting the on-site production needs.