西山煤田西铭矿区陷落柱的地质特征及成因分析

Characteristics and Genesis of Collapse Column in Ximing Mine of Xishan Coalfield

本文根据陷落柱伴生构造的特征和华北地区煤系地层下伏巨厚奥陶系灰岩 ,且中夹厚层硬石膏层 ,硬石膏遇水转变为石膏 ,其体积膨胀等特征 ,论述了陷落柱是因硬石膏遇水不断转变为石膏 ,体积膨胀时 ,破坏其上覆岩层 ,其后经过漫长的时间 ,在地下水溶蚀作用下 ,奥灰及石膏层被溶蚀 ,形成溶洞 ,上覆岩层因整体性被破坏 ,受地壳运动的影响或在重力作用下 ,很容易冒落下来 ,形成陷落柱。其后再溶蚀 ,再塌陷 ,不断循环这一过程 ,直至其下可溶性岩石被全部溶蚀 ,并塌陷冒落严实。

Based on the feature of accompanying faults of the collapse column,large thickness Ordovician limestone,which contains large thickness anhydrite,existing under the coal measure and after the action of anhydrite with water its volume will expand,discusses the genesis of the collapse column is that while the anhydrite ,s volume is expanding,the rock layers upon it are destroyed.With the time going the limestone and anhydrite layers are dissolved and the corrosion cavity are formed.Under control of the crustal movement or gravity,the rock layers upon the limestone are very easy to subside.The cycle of dissolving and subseding will results in the formation of the collapse column.