干湿循环下云南非饱和红土土—水特性研究  

Study on Soil-water Characteristics of Unsaturated Yunnan Laterite Under Wet-dry Cycle

作　　者：黄英[1] 程富阳 金克盛[1] HUANG Ying;CHENG Fuyang;JIN Kesheng(Kunming University of Science and Technology, Kunming 650500;State Grid Hubei Electric Power Co., Ltd., Yuan’an County Power Supply Company, Yuan’an, Hubei 444200)

机构地区：[1]昆明理工大学,昆明650500 [2]国网湖北省电力有限公司远安县供电公司,湖北远安444200

出　　处：《水土保持学报》2018年第6期97-106,共10页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(51568031)

摘　　要：以云南红土为研究对象,以脱湿、吸湿引起的干湿循环作为控制条件,考虑初始干密度(1.20,1.25,1.30g/cm3)、初始含水率(30.0%,33.0%,36.0%)、预固结压力(0,50,100,200kPa)、过筛粒径(0.5,1.0,2.0mm)等影响因素,通过压力板仪法,研究干湿循环下云南非饱和红土的土—水作用特性。结果表明:干湿循环过程中,不同影响因素下红土的基质吸力随含水率的增大而减小,其土—水特征曲线呈直线型或"倒J"形,其脱湿变化过程可以分为快速脱湿、缓慢脱湿、稳定脱湿3个阶段,对应的吸湿变化过程也可以分为快速吸湿、缓慢吸湿、稳定吸湿3个阶段。相同基质吸力下,随初始干密度、初始含水率、预固结压力的增大,红土的含水率增大;随粒径的增大,红土的含水率减小。初始干密度、预固结压力、粒径(0.5mm除外)影响下的红土的土—水特征曲线可采用幂函数关系进行拟合,不同初始含水率、粒径0.5mm时的土—水特征曲线可采用线性函数关系进行拟合。红土脱湿过程的含水率高于吸湿过程的含水率,脱湿—吸湿过程中的土—水特征曲线存在滞后现象,其实质在于干湿循环作用下红土具有孔隙效应、瓶颈效应、角度效应的综合结果。The paper takeYunnan laterite as the object,soil-water characteristics under wet-dry cycle by the pressure plate method were explored,meanwhile,factors such as initial dry density(1.20,1.25and1.30g/cm3),initial moisture content(30.0%,33.0%and36.0%),pre-consolidation pressure(0,50,100and200kPa),and particle size(0.5,1.0and2.0mm)were taken into considrearion.The results showed that laterite’s matric suction decreased with increasing moisture content during the wet-dry cycle,and the soil-water characteristic curve was“inverted J”.The soil-water characteristic curve could be divided into three stages,which included rapid dehydration,slow dehydration,and stable dehydration,and the corresponding moisture absorption process could also be divided into three stages:rapid moisture absorption,slow moisture absorption,and stable moisture absorption.Under the same matrix suction,laterite moisture content increased with the increase of initial dry density,initial moisture content and pre-consolidation pressure,while laterite moisture content decreased with the increase of particle size.Laterite soil-water characteristic curve could be fitted by power function,while initial dry density,pre-consolidation pressure,particle size(except0.5mm),and soil-water characteristic curve could be fitted with a linear function.The moisture content of the laterite dehumidification process was higher than that of the moisture absorption process.There was a hysteresis in the soil-water characteristic curve during the process of moisture removal and moisture absorption.It was ascribed to the effects of pore size,bottle neck,contact angle and cyclic expansion and shrinkage of laterite under wet and dry cycles.

关 键 词：云南非饱和红土 干湿循环作用 不同影响因素 土-水特征曲线 拟合关系 

分 类 号：TU411.91[建筑科学—岩土工程]