岩层厚度对砂泥岩水平互层岩体力学特性的影响

Influence of Rock Thickness on Mechanical Characteristics of Horizontal Interbedded of Sandstone and Mudstone

该文针对砂泥岩水平互层岩体,基于FLAC3D数值分析方法,分别采用层厚比(泥岩层厚与砂岩层厚之比)与岩层密度(一定岩体厚度范围内的岩层数)表征砂泥岩水平互层岩体的相对岩层厚度和绝对岩层厚度,分析了不同岩层厚度对砂泥岩水平互层岩体的单轴抗压强度及变形特征的影响。研究表明:砂泥岩水平互层岩体的层厚比以0.75为界限,当层厚比小于0.75时,砂泥岩水平互层岩体的单轴抗压强度随层厚比的增加而大幅减小,随岩层密度的增加大幅增加。因此,实际工程中应综合考虑层厚比及岩层密度两种因素对岩体强度的影响进行取值;当层厚比大于0.75时,砂泥岩水平互层岩体的单轴抗压强度随层厚比的增加稍有减小,随岩层密度的增加稍有增加,但总体上趋于稳定,并接近于泥岩的抗压强度,因此,实际工程中可按泥岩的抗压强度进行取值。

In this paper, according to the sandstone mudstone horizontal interbedded rock mass, based on FLAC3 D numerical analysis method, the relative thickness and absolute thickness of sandstone and mudstone horizontal interbedded rockmass are characterized by layer thickness ratio(the ratio of mudstone layer thickness to sandstone layer thickness) and layer density(the number of layers within a certain range of rock thickness). The uniaxial pressure resistanc and deformation characteristics of sandstone and mudstone horizontal interbedded rockmass with different layer thickness are analyzed. The results show that the thickness ratio of horizontal interbedded rockmass of sandstone and mudstone is 0.75, when the thickness ratio is less than 0.75, the uniaxial compressive strength of horizontal interbedded rockmass of sandstone and mudstone decreases greatly with the increase of thickness ratio, and increases greatly with the increase of rock density. Therefore, in practical engineering, the influence of thickness ratio and rock density on rock strength should be comprehensively considered to select the value. When the thickness ratio is greater than 0.75, the uniaxial compressive strength of horizontal interbedded rock mass of sandstone and mudstone slightly decreases with the increase of the thickness ratio, and slightly increases with the increase of the rock density, but generally tends to be stable and closes to the compressive strength of mudstone. Therefore, the value can be determined according to the compressive strength of mudstone in practical engineering.