不同压实度花岗岩残积土的渗流模拟  

Seepage Simulation of Granite Residual Soil with Different Compaction Degrees

作　　者：王志兵[1,2] 谈勋勋 王远 孙广 刘金明 WANG Zhi-bing;TAN Xun-xun;WANG Yuan;SUN Guang;LIU Jin-ming(College of Civil Engineering,Guilin University of Technology, Guilin 541004, China;Guangxi Key Laboratory of Rock-soil Mechanic and Engineering, Guilin 541004, China)

机构地区：[1]桂林理工大学土木与建筑工程学院,桂林541004 [2]广西岩土力学与工程重点实验室,桂林541004

出　　处：《科学技术与工程》2021年第14期5913-5921,共9页Science Technology and Engineering

基　　金：国家自然科学基金(51768015);广西自然科学基金(2017GXNSFAA198092)。

摘　　要：以桂东南地区不同压实度的花岗岩残积土为研究对象,结合显微CT(micro computed tomography,微计算机断层扫描技术)扫描试验与Avizo软件中先进的数字图像处理技术提取孔隙网络模型。然后基于流体力学的传统方法(computational fluid dynamics,CFD),将孔隙结构的数字岩心模型导入Comsol进行微观尺度的渗流模拟,从微观角度研究水在不同压实度花岗岩残积土孔隙中的渗流特性,并与实测渗透率对比,检验数字岩心模型准确性、代表性。研究结果表明:花岗岩残积土渗流过程中,最大速度出现在连通性好的孔隙中心区域,且远超其他部位,沿着孔隙中心向外壁的方向,渗流速度逐渐减小;在连通性差的区域,流速近乎为0。随着压实度的增加,花岗岩残积土的孔隙连通性变差,各个截面上的孔隙结构发生变化,且各截面的平均渗流速度逐渐减小,这表明压实度对花岗岩残积土的渗流特性有重要影响。压实度为90%、100%、110%花岗岩残积土的平均渗透率模拟值分别是实测值0.9、1.35、0.77倍,该数字岩心模型能较准确地代表压实土体内部真实的孔隙渗流特征。The granite residual soil with different compaction degrees in southeast Guangxi was taken as the research object.Firstly,the pore network model was extracted by combining the micro-computed tomography(CT)scanning test and the advanced digital image processing technology in the Avizo software.Then,based on the traditional method of fluid mechanics(CFD),the digital core model of pore structure was imported into Comsol to simulate the seepage at the micro-scale,and the seepage characteristics of water in the pores of granite residual soil with different compaction degrees were studied from the microscopic point of view.And it was compared with the measured permeability to test the pore accuracy and representativeness of the digital core model.The research results show that during the seepage process of granite residual soil,the maximum velocity appears in the pore center area with good connectivity,and far exceeds other parts,along the direction of the pore center to the outer wall,the seepage velocity gradually decreases.In areas with poor connectivity,the flow rate is almost zero.As the degree of compaction increases,the pore connectivity of the granite residual soil deteriorates,and the pore structure of each section changes.The average seepage velocity of each section gradually decreases,which shows that the degree of compaction affecting the seepage characteristics of the granite residual soil has an important impact.The simulated values of average permeability of granite residual soil with compaction degrees of 90%,100%,and 110%are 0.9,1.35,and 0.77 times of the measured values,respectively.Pore seepage characteristics of compacted granite residual soils can be accurately modeled by the digital core model.

关 键 词：压实度 花岗岩残积土 孔隙网络模型 渗流模拟 显微CT扫描 绝对渗透率 

分 类 号：TU432[建筑科学—岩土工程]