黄土节理力学性质对地表开采沉陷的影响研究

Research in Mechanical Parameters of the Loess Joints under the Condition of Mining Subsidence

垂直节理在黄土层中发育极为普遍,是黄土的主要特征之一,与之相关的力学性质研究业已广泛开展。通过采用AutoCAD、Ansys、FLAC^(3D)联合建模的方法,构建了黄土地区近水平煤层开采沉陷遍布节理模型,以大贝峁煤矿为研究区域,开展了地表开采沉陷背景下黄土及其垂直节理在受挤压、受拉、抗剪与塑性破坏状态的模拟研究,剖析了黄土含水量变动引发的黄土节理力学参数的变化机理,建立了含水量与抗剪强度的数值映射关系,进而得出由含水量变动引发的黄土节理抗剪强度与剪胀性的协调变动机制。研究表明:黄土节理的性状对整体黄土覆盖层沉陷的影响显著;而含水量作为改变黄土性状的重要驱动因素,直接引发其抗剪强度与剪胀性按照特定机制协调变化,从而影响地面沉陷结果。

As one of the main characteristics of Loess,loess vertical joint is very common in the Loess layer,and the study on the mechanical properties related to it has been widely carried out. In this paper,through Auto CAD,Ansys,FLAC^3D combined method,the ubiquitous-joint model of flat seam exploitation in the loess area was built.With Dabeimao coal mine as the study area,the state of loess and its vertical joints with compression,tension,shear and plastic failure under the surface mining subsidence are simulated,the mechanism of loess joint mechanical parameters caused by the change of water content of loess is analyzed.Simultaneously,the numerical mapping relationship between water content and shear strength is established,and then,the coordination mechanism of the shear strength and dilatant of loess joints caused by the change of water content is obtained.The results show that the characteristics of loess joints is an important factor that affects the loess layer subsidence;and water content is the key driving factor for the change of loess characteristics,which cause the synergistic change of shear strength and dilatant of Loess according to specific mechanisms,thus affecting the result of ground subsidence changes.