岩石裂隙中非恒定渗流与变形耦合作用的DDA方法

Study on the coupling effect of the unsteady seepage in rock fractures with the rock deformation by using DDA (discontinuous deformation analysis) method

由于渗流作用,会在岩石裂隙中形成非稳定流,非稳定流作为裂隙表面荷载会使岩体产生变形,变形又会影响岩土结构的渗流特性,从而产生渗流和变形耦合的作用.根据最小能量原理构造出单元DDA(不连续变形分析)瞬时平衡方程.编制了基于DDA的岩石裂隙中稳定渗流和不稳定渗流压力水头的有限单元计算程序,通过对实验结果与计算结果的比较,验证了计算程序所使用的数学模型的可靠性.地下水是影响边坡受力变形及稳定性的一个重要因素.通过对某隧洞破坏过程的模拟,用这种渗流-变形耦合DDA法研究了地下水对裂隙边坡稳定性的影响.模拟结果与实际发生的结果一致,验证了本文方法的可靠性.

This paper aims at analyzing the coupling effect of the unsteady seepage in rock fractures with the rock deformation.Due to the seepage,the unsteady flow will be formed in rock fractures.The unsteady flow will produce a load on the surface of the fractures and make the rock produce deformation,and then the deformation will influence the seepage characteristics of the rock.So the seepage field and the deformation field form the coupling effect.The DDA instantaneous equilibrium equation of the fracture network units is established according to minimum energy principle.The finite element programs for computing the water heats of the steady flow and unsteady flow in the rock fractures based on DDA are compiled,the computed results accord with experimental results,which verifies the reliability of the mathematical models used in the programs.Groundwater is one of the important factors influencing the deformation and stability of side slope.Through the simulation of the destructive process of some tunnel,the seepage—deformation coupling DDA method is used for studying the effect of groundwater on the stability of fracture side slope.The simulation result accords with the actually generated result,which verifies the reliability of the method.