重塑高岭土渗透各向异性影响因素  

Factors influencing permeability anisotropy of remolded kaolin

作　　者：余良贵 周建[1,2] 温晓贵[1,2] 徐杰[1,2] 罗凌晖 YU Liang-gui;ZHOU Jian;WEN Xiao-gui;XU Jie;LUO Ling-hui(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;Engineering Research Center of Urban Underground Development of Zhejiang Province,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江大学浙江省城市地下空间开发工程技术研究中心,浙江杭州310058

出　　处：《浙江大学学报（工学版）》2019年第2期275-283,372,共10页Journal of Zhejiang University：Engineering Science

基　　金：国家重点研发计划资助项目(2016YFC0800203);国家自然科学基金资助项目(51338009)

摘　　要：为了研究软土渗透各向异性,以重塑高岭土为研究对象,利用三轴渗流仪对重塑高岭土展开一系列渗流试验,研究电解质类型、浓度及固结压力对软黏土渗透各向异性的影响,并从微观角度解释其作用机理。研究发现:1)高岭土颗粒为扁平状结构,在一维固结下颗粒趋向于垂直于主应力方向排列,重塑高岭土竖向剖面孔隙面积大于水平向剖面孔隙面积,这2个因素共同导致渗透各向异性比(水平渗透系数与垂直渗透系数之比)大于1;2)渗透各向异性比随固结压力增大而减小,主要是因为竖向剖面大孔隙较多,压力作用下竖向剖面孔隙面积减小幅度大于水平剖面孔隙面积减小幅度;3)马来西亚高岭土在高纯水下为絮凝状结构,在盐溶液下为散凝状结构,在高纯水下土体竖向剖面大孔隙较多,而在盐溶液下竖向剖面孔隙和水平向剖面孔隙较为接近,导致在高纯水下测得的渗透各向异性比在盐溶液下的测量结果大;4)在本试验条件下,电解质类型、浓度对马来西亚高岭土渗透各向异性比的影响均较小。A series of experiments were conducted by triaxial permeameter to analysis the permeability anisotropy of soft soil.The effects of electrolyte type,ionic molar concentration and consolidation pressure on permeability anisotropy and the corresponding microscopic mechanisms were investigated,with remolded kaolin as the research object.Results showed that under one-dimensional consolidation,kaolin particles,most having flat structure,tended to orientate perpendicularly to the direction of the major principal stress and the pore area of remolded kaolin in vertical profile was much larger than that in horizontal profile.As a result,permeability anisotropy ratio(ratio of horizontal to vertical permeability coefficients)was greater than one.Permeability anisotropy ratio decreased with the increase of consolidation pressure,of which the main reason was that the amount of large pores,which had higher compressibility,in vertical profile was larger than that in horizontal profile.Malaysia kaolin has flocculated structure if prepared in ultrapure water,while has dispersed structure in saline solution.The measured permeability anisotropy ratio in ultrapure water was larger than that in saline solution,which was the consequence of more large pores in vertical profile than that in horizontal profile in ultrapure water.The vertical and horizontal profiles had similar amounts of large pores in saline solution.Test results also revealed that the electrolyte type and ionic molar concentration had little effect on the permeability anisotropy ratio of Malaysia kaolin.

关 键 词：渗透各向异性 重塑高岭土 电解质溶液 固结压力 微观结构 

分 类 号：TU47[建筑科学—结构工程]