房采采空区顶板大面积冒落对巷道危害及防治

Damage to Roadway by Large-Scaled Roof Falling in a Mined-Area of Room and Pillar Mining and Its Prevention

房柱式采煤方法所特有的回采方式,采空区内遗留大量的煤柱.采空区顶板在煤柱的支撑下,悬露面积越来越大.当悬顶跨度达到一定的程度时,遗留煤柱会因应力的转移承受的载荷增加发生失稳,顶板失去支撑,大面积切断冒落,在短时间内压缩采空区气体,形成高速气体流涌入巷道.此过程会对巷道产生严重的冲击灾害,造成人员与设备的损失.针对这一灾变运用流体力学理论,建立了简单的气体压缩活塞模型,对这一灾变对巷道造成的冲击压强进行了理论推导.结合某矿的具体情况,针对这一灾变提出了构筑防冲密闭墙的防治措施,并对密闭墙的厚度进行了计算.

The unique method in gob of room and pillar mining leaves behind a large number of coal pillars.Under the support of coal pillars,the area of roof in gob is bigger and bigger. When the area reaches a certain extent,the coal pillars will collapse due to the stress transfer. The roof falls down in a large scale without supporting and compresses the gob gas in short time. High-speed gas flows into the roadway. This process will have a serious impact on the roadway,resulting in the loss of personnel and equipment. In connection with this disaster,this paper establishes a simple model of compressed gas. It makes the theoretical derivation from the impact-stress to roadway caused by this disaster. Combined with the specific circumstances of a mine,this paper puts forward protective measures of building anti-impact closed walls,and calculates its thickness.