用渗透性随埋深变化趋势反求岩体变形模量的简化模型

SIMPLIFIED MODELS IN ESTIMATING DEFORMATION MODULE OF ROCKS BY USING DEPTH-DEPENDENT PERMEABILITY

取得大尺度范围岩体的宏观力学参数是地质工程领域的难题。渗透性随埋深衰减的趋势恰恰反映岩体在大尺度范围的渗流场-应力场耦合行为,为解决这个问题提供契机。根据自重应力作用下岩体的应变-渗透耦合机制,以孔隙度和裂隙宽度为中间参数,建立利用渗透性随埋深变化趋势反求岩体变形模量的简化模型,推导了岩块体积模量和结构面法向刚度的反演公式。这种简化模型是在假设岩体物质结构相对均匀、只存在单组裂隙、无构造应力的理想情况下建立的,但为获取大尺度范围岩体的宏观应力-应变参数提供一种新的参考途径。

In geotechnical engineering, it is difficult to determine micro-mechanical parameters of large-scale rock mass. However, the depth-dependent permeability, due to coupling of seepage field and stress field in large-scale rock mass, suggests a chance to solve the problem. According to the hydro-mechanical coupling behaviors of rock mass under geostatic pressure, simplified models in estimating deformation module of rocks by using depth- dependent permeability is developed. Porosity and opening of rock fractures are applied to the transition factors in deriving equations for bulk modules of intact rock and normal stiffness of joints. The models is limited with assumptions such as the rock mass is relatively uniform, containing one group of joints and without tectonic stress. However, the assumptions are not serious limitations in suggesting this new way to determine micro-mechanical parameters of large-scale rock mass.