马达岭滑坡室内岩石力学试验研究

Testing studies of rock mechanics in lab for the Madaling landslide

马达岭滑坡所在的自然边坡为一典型的缓倾斜横向斜坡,岩层近南北走向,呈软硬互层状结构。岩性以砂岩为主,坡体内存在大量软岩夹层和裂隙。斜坡下120m处发育有2层可采煤层,且煤层开采后留下大量采空区。斜坡的变形及稳定性主要受采空区顶板砂岩和坡脚煤岩的强度特性控制,本文以室内岩石力学试验为基础,系统研究了砂岩的基本力学属性及煤岩的抗剪强度特性,并分别分析了两种岩石的变形破坏特征。综合分析实验结果表明,砂岩的抗拉强度在坡体稳定性评价中起着控制性作用;煤岩的抗剪强度对斜坡稳定性影响最为直接;受层面控制,煤岩抗剪强度值较小,而其残余强度较峰值强度更是减小了60%;2种岩石的变形破坏特性受其风化程度不同,都存在较大差异。

The orientation of the Madaling landslide is a typical slightly inclined slope with a nearly North-South trend and a soft and hard mutual layer structure.The primarily rock of the slope is sandstone,carbon shale and coal.Inside the slope,there exist a large number of soft rock sandwich and cracks.Two workable coal seams lay in 120m from the top of the slope,and a lot of mined-out area appeared under the slope after the mining of the coal seams.The deformation and stability of the slope is mainly controlled by the strength characteristics of sandstone in roof and the coal seams located in the slope toe.This paper examined the main behaviors of deformation and strength of sandstone and the shear strength characteristics of coal based on the laboratory experiments of rock mechanics,and analyzed the deformation characteristics of the two representative rocks.The results from the tests and the comprehensive analyses indicate that the tensile strength of the sandstone has a controlling role in the stability of the slope and the tensile strength of the coal has the most direct influence on the slope stability.Controlled by the bedding plane,the tensile strength of the coal is very low,and the residual strength is reduced by 60% compared with the peak strength.Significant difference exists in the deformation characteristics of the two rocks because of the different weathering degree.