湿度和冻融循环影响下膨胀土的压缩特性及孔隙结构特征  

Effects of humidity and freeze-thaw cycles on compression and pore structure characteristics of expansive soils

作　　者：韩仲 邹维列[1,2] 裴秋阳 王协群[3] 张红日 HAN Zhong;ZOU Weilie;PEI Qiuyang;WANG Xiequn;ZHANG Hongri(School of Civil Engineering,Wuhan University,Wuhan 430072,China;Key Laboratory of Hydraulic Rock Mechanics of Ministry of Education,Wuhan University,Wuhan 430072,China;School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China;Guangxi Transportation Science and Technology Group Co.,Ltd.,Nanning 530007,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]武汉大学教育部水工岩石力学重点实验室,湖北武汉430072 [3]武汉理工大学土木工程与建筑学院,湖北武汉430070 [4]广西交科集团有限公司,广西南宁530007

出　　处：《岩土工程学报》2025年第3期495-505,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52378365,52179109,52078400);广西重点研发计划项目(AB23075184)。

摘　　要：通过试验和理论研究,探讨了湿度状态及冻融循环对黑龙江膨胀土的一维压缩特性及孔隙结构特征的影响。将压实膨胀土样平衡至不同含水率后进行冻融循环试验及饱和处理,开展常含水率压缩试验及固结试验分别确定非饱和试样及饱和试样的压缩曲线及相应压缩特性参数,并通过压汞试验测定膨胀土的孔隙结构特征。试验结果表明:(1)在弹性压缩段,膨胀土的再压缩指数(C_(e))对含水率变化不敏感,但在冻融循环后显著增大;(2)在弹塑性压缩段,随着含水率降低,先期固结压力增大而压缩指数(C_(c))减小。冻融循环后,先期固结压力与C_(c)均减小;(3)不同湿度和冻融循环条件下,C_(e)与土体的大孔隙含量(e_(l))间存在统一的线性关系,C_(c)与e_(l)、中孔隙含量(e_(m))及土体湿度状态构成的细观参数间存在统一关系。基于试验结果,构建了考虑湿度状态及冻融循环影响的膨胀土压缩曲线模型。该模型能够准确描述压实膨胀土的孔隙比-应力-含水率关系。Through the experimental and theoretical studies,the effects of humidity and freeze-thaw(FT)cycles on the compression and pore structure characteristics of a compacted expansive soil have been investigated.The compacted specimens are equilibrated to different moisture contents and then subjected to the FT cycles and saturation process.The constant water content compression tests and consolidation tests are conducted to determine the compression curves for unsaturated and saturated specimens,respectively.The mercury intrusion porosimetry tests are performed to determine the pore structure characteristics of the soil.The experimental results indicate that:(1)Within the elastic range,the recompression index(C_(e))is insensitive to the moisture content but increases significantly after the FT cycles.(2)Within the elastoplastic range,the preconsolidation pressure increases while the compression index(C_(c))decreases as the moisture content decreases.Both the preconsolidation pressure and C_(c) decrease after the FT cycles.(3)Under different humidity and FT conditions,there exists a unique linear relationship between C_(e) and the void ratio of macropores(e_(l))and a unique relationship between C_(c) and mesoscopic parameter that is composed of el,void ratio of medium pores(e_(m))and humidity conditions.Based on the test results,a model is proposed to describe the compression curves of expansive soils considering the effects of humidity and FT cycles.The model is found to be capable of suitably describing the void ratio-stress-moisture content relationships for compacted expansive soils.

关 键 词：膨胀土 湿度 冻融循环 压缩特性 孔隙结构 

分 类 号：TU43[建筑科学—岩土工程]