司马煤矿薄基岩区松散层特性与煤层安全开采

Relationship between Loose Soil Property and Safety Mining in Thin Bedrock Area of Sima Mine

结合司马煤矿因松散层底板隔水黏土层存在大量"漏洞"的实际条件,运用数值模拟等方法定义并圈定了薄基岩区;通过钻孔岩性组合分析,岩土及渗透力学取样测定,岩相古地理研究等对松散层形成条件及垂向导水性能进行了研究.结果表明:司马矿松散层上部赋存主要含水层,而其中下部以黏土为主;第四系沉积中心为古河口,其沉积物厚度大、颗粒细、含导水性差,河道两侧沉积物颗粒变粗、厚度变薄、垂向渗透能力增强,根据基岩古地形即可划分出松散层垂向越流能力的强弱区;古河口沉积覆盖了薄基岩区的大部分,有利于水、沙控制;底部自承力强的硬黏土减小了支架的附加载荷,开采实践检验了研究结论的正确性.

Aiming at the actual situation of large amount of holes resulted from the loose floor of water insulation clay layer in Sima mine, we defined and delineated the area of thin bedrock area through numerical simulation. In addition, we analyzed the lithologic association of drilling holes, collected samples for testing their rock mechanics properties, and studied the effect of lithofacies palaeogeography on forming loose clay layer and on water conductivity. The result shows that： 1） In Sima coal mine, the principal aquifer distributes mainly in upper quaternary loose soil while the clay layer is dominant in middle and lower area; 2） The area of ancient river mouth which is now quaternary sediment center is characterized by thick sediment with small sized grains and by poor permeability while the area around the center is characterized by thin sediment with large sized grains and by good permeability; 3） Based on the ancient landform of bedrock, we can divide the loose layer into the good vertical permeability area and the bad one; 4） Sediments in the ancient river mouth covers a large portion of bedrock area, quite favorable for water and sand control; And 5） the bottom hard clay with great self-bearing force makes the additional load of support decreased, which has been proven true by mining practice.