石膏矿采空区上覆岩层冒落规律与危险性评价

Study on the Caving Laws of Overlying Strata in Gypsum Mine Goaf and Its Risk Assessment

为对上覆岩层冒落的危险性进行有效评价,在工程实勘的基础上,将石膏矿上覆岩层的自然冒落作为一个逐级发展的过程来处理,并根据普氏平衡拱理论对各级拱形作出2点假定,即冒落拱顶部弧线为抛物线,矿柱按θ角剥蚀。提出以临界松散系数K作为其危险性评价因子,并根据所建立的一般冒落拱模型,分别推导得到条带矿柱及间隔点柱区域关于K的计算公式。最后,将该评价因子用于工程实际,实现对邵东石膏矿采空区的危险性分级。该评价体系,即可对石膏矿地表塌陷作出有效预测,也可对石膏矿地表危险程度进行合理分级。

In order to make an effective assessment of the hazard which caused by the caving of overlying strata,based on field investigation,the caving of overlying strata over abandoned mine goaf was regarded as a step-by-step development process.Then,according to PU＇s equilibrium arch theories,two assumptions about the shape of arch at different levels were made,namely,the crown arc of the caving arch was parabola and the pillars were denuded at an angle of θ.Through further analysis,different developmental patterns of the caving arch were gotten,and a general caving arch model was established.Based on these,the critical loose coefficient K was proposed as the risk assessment factor,and the corresponding formula in the mined-out area reserving strip pillar and post pillar was derived from the general caving arch model respectively.At last,the risk assessment factor was applied to the engineering practice,and the risk classification of Shaodong gypsum mine was made.This evaluation system cannot only make an effective forecast for the surface collapse of gypsum mine,but also be used to rank the dangerous degree of gypsum mines surface.