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真实土体的细观结构由许多个大小不一的土颗粒团组成,传统四参数随机生长法(QSGS)构建的土体结构土颗粒团比较均匀,与实际情况存在较大的差异。为弥补这一缺陷,考虑土体孔隙率及自相关函数的影响,对传统的四参数随机生长法进行改进,实现了更接近于真实土体的细观结构重构。在此基础上基于格子Boltzmann方法,采用D2Q9模型,通过设置模型入口、出口边界为非平衡态外推格式,左右边界及土颗粒边界为标准反弹格式的边界条件,建立了模拟重构土体细观渗流场的二维模型。同时,针对一算例编制了相应的计算程序,研究了恒定流速入渗情况下重构土体的细观渗流场。研究表明:土体的渗流方向优先选择连通性较好孔隙所形成的通道,流速受控于通道整体连通性的优劣。整体贯通型的通道流动速度较快,部分连通的孔隙中其流动速度相对较慢。即使局部孔隙空间较大,其渗流速度仍取决于是否位于贯通型通道上。
The mesostructure of the real soil consists of many soil particles with different sizes. The soil particles formed by the traditional four-parameter random growth method (QSGS) are relatively uniform, which is quite different from the actual situation. In order to remedy this defect, considering the influence of soil porosity and autocorrelation function, the traditional four-parameter stochastic growth method is improved to realize the meso-structure reconstruction that is closer to the real soil. Based on the lattice Boltzmann method, the D2Q9 model is adopted. By setting the boundary of the model inlet and exit boundary to the non-equilibrium state extrapolation, the left and right boundary and the soil particle boundary as the standard rebound format, Two-dimensional model of seepage seepage field. At the same time, a corresponding calculation program is compiled for a case study, and the mesoscopic seepage field of reconstructed soil under constant flow velocity infiltration is studied. The results show that the preferential flow direction of soil is chosen as the channel with better connectivity, and the flow velocity is controlled by the overall connectivity of the channel. The overall penetration of the channel flow faster, part of the communication of the pores in its relatively slow flow. Even if the local pore space is large, the seepage velocity depends on whether it is located in the through-channel.