双系煤层开采相互影响下的覆岩运动与破坏规律分析

Research on the law overburden movement and failure under the influence of double period coal seam mining

以大同矿区同忻煤矿为例,利用关键层理论、物理探测技术和数值模拟,分析双系煤层开采形成的覆岩运动与破坏规律。研究结果表明：（1）石炭二叠系煤层工作面推进至193 m时,覆岩裂隙带发育高度达到最大为174.7 m;（2）物理探测得到3-5^#煤层开采引起的覆岩垮裂带高度约为180 m,综合理论计算与现场实测,确定覆岩裂隙带发育高度与采厚之比为11.7-12.0;（3）侏罗系煤层开采引起的底板破坏及双系间覆岩软弱夹层的缺失为双系煤层采空区联通进一步提供了条件;（4）侏罗系煤层的开采影响石炭二叠系煤层工作面超前支承压力的分布规律,当石炭系煤层工作面位于侏罗系煤层遗留煤柱下方时,超前支撑压力较无采空区时增大12.4%;（5）研究成果揭示了双系开采相互影响关系,为采取安全开采措施、减弱双系开采相互影响程度提供了科学依据。

Taking the Tongxin coal mine as a case study,the law of overburden movement and failure caused by double period coal seam（ DPCS） mining is analyzed by using of key strata（ KS） theory,the physical detection and numeric simulation technology. The results show that：（ 1） When workface advances to 193 m,the height of overburden fractured zone（ OFZ） has a maximum of 174. 7 m;（ 2） The height of OFZ caused by 3- 5#seam mining which is obtained by physical detection is about 180 m,the ratio of height of OFZ and mining thickness is 11. 7 -12. 0 by theoretical calculation and field test;（ 3） The floor damage caused by Jurassic coal mining and lack of soft interlayer provide further conditions to connectivity of double period coal goaf;（ 4） Jurassic coal mining influences the variation of advanced support pressure of Permo-Carboniferous coal seam. When Permo-Carboniferous coal seam coal workface is located at the bottom of Jurassic coal pillar,the advanced support pressure is increased by 12. 4% than those without goaf.（ 5） These results reveal the interactional relationship of DPCS mining,which provides a scientific basis to take security measures to weaken mutual influence of mining.