基于改进滤失试验的CaCl_2溶液作用下膨润土滤饼渗透系数  

Hydraulic conductivity of bentonite filter cakes in concentrated calcium chloride solutions based on modified fluid loss test

作　　者：沈胜强[1,2] 杜延军[1,2] 张润[1,2] 梅丹兵 

机构地区：[1]东南大学岩土工程研究所,南京210096 [2]东南大学江苏省城市地下工程与环境安全重点实验室,南京210096

出　　处：《东南大学学报（自然科学版）》2016年第A01期179-183,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金重点资助项目(41330641);国家自然科学基金资助项目(51278100;41472258);江苏省自然科学基金杰出青年基金资助项目(BK 2012022)

摘　　要：由于隔离墙施工过程中形成的膨润土滤饼对土-膨润土隔离墙整体防渗性能起到重要作用,采用改进滤失试验测试了不同压力下受CaCl_2溶液和去离子水作用的膨润土滤饼渗透系数kc和kw.结果表明,同浓度CaCl_2溶液作用下,随试验压力增大,膨润土滤饼渗透系数呈降低趋势;同一压力下,滤饼渗透系数随CaCl_2浓度增大而增大.由试验压力增长引起的滤饼孔隙比的减小,可降低滤饼的渗透系数;而由CaCl_2浓度增大所造成的滤饼孔隙比的减小则增大了滤饼的渗透系数.当CaCl_2浓度>15 mmol/L时,膨润土泥浆试样无法形成滤饼,膨润土的kc/kw将大于10,其渗透系数将显著增长.Due to the bentonite filter cake formed during cutoff wall construction plays an important role on hydraulic performance of soil-bentonite vertical cutoff wall, the hydraulic conductivities, kc and kw, of bentonite filter cakes by calcium chloride solution and deionized water actions under different stress are measured by modified filtrate loss tests. The results indicate that the hydraulic conductivity of bentonite filter cakes decreases with the increase of total stress at the same CaCl2 concentration, and increases with an increase in CaCl2 concentration under the same total stress. The decrease of filter cake void ratio resulting from the total stress increase leads to the decrease of hydraulic conductivity of filter cake; while the decrease of filter cake void ratio caused by the CaCl2 concentration increase results in the increase of hydraulic conductivity of filter cake. When the CaCl2 concentration is greater than 15 mmol/L, the filter cake cannot be formed, and the kc/kW of CB filter cake is greater than 10. Thus, the hydraulic conductivity of CB increases obviously.

关 键 词：膨润土滤饼 渗透系数 化学相容性 

分 类 号：TU443[建筑科学—岩土工程]