盐渍土土水特征曲线测试及预测  

Test and prediction of SWCC of saline soil

作　　者：于沉香[1] 张虎元[1] 王志硕[2] 赵天宇[1] 

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [2]中国水电顾问集团西北勘测设计研究院,陕西西安710065

出　　处：《水文地质工程地质》2013年第2期113-118,共6页Hydrogeology & Engineering Geology

摘　　要：作为一种特殊土,盐渍土有着独特的工程性质并由此引发了盐胀、溶陷等工程问题,其发生及发展均与土体含水量密切相关,不同含水量条件下土中的吸力也对土体工程性质有着较大影响。本文选取甘肃酒泉地区的盐渍土,室内利用Ku-pF非饱和导水率仪测试了不同干密度状态下盐渍土试样的土水特征曲线,发现渗透吸力的存在使得盐渍土试样的土水特征曲线转化阶段较一般土平缓,同一含水量条件下土中的吸力较一般土大,土体持水能力有所增强。不同干密度试样土水特征曲线的测试结果表明,干密度增大后土中大孔隙减少,中、小孔隙增多,孔隙连通性变差,导致土样饱和含水量降低,进气值增大,失水速率减慢,土体持水能力有一定增强。对比国内外广泛使用的模型对实测盐渍土土水特征曲线进行拟合,发现Fredlund and Xing模型能较好地反映盐渍土土中吸力与含水量的关系。最后,基于盐渍土的颗粒累积分布曲线及其基本物理指标,依据Fredlund物理-经验预测模型的理论和方法,预测了不同干密度盐渍土的完整土水特征曲线,以期为盐渍土地区土体工程性质的研究和预测提供理论支持和有益参考。As a kind of special soil,saline soil has many particular engineering characteristics and may cause many engineering problems,such as salt heaving and collapsibility,which are closely related to soil water content.Soil suction under different water content has great influence on engineering properties.This paper selects the saline soil in Jiuquan area of Gansu to measure soil water characteristic curves of different dry density samples using the Ku-pF apparatus.The results indicate that the existence of osmotic suction in saline soil causes gentle slope at the transformation stage of SWCC and soil suction at the same water content is higher than that of general soil.As a result,water content capability enhances.The increase in dry density minimizes big pores and augmentes medium and small pores of the sample.The pore connectivity thus becomes poorer and saturated moisture content of sample is reduced.The air entry value is increases and the rate of dehydration decreases.Thus,the water storage capability was strengthened.Models widely used at home and abroad are contrasted to fit the experimental data,demonstrating that Fredlund and Xing's(1994) model can well reflect the relationship between water content and soil suction in the saline soil.Based on grain-size distribution and physical properties of the saline soil,the SWCC curve of different dry density samples over the entire soil suction range are predicted according to the theory and method of Fredlund physical-empirical model.The results may provide theoretical support and beneficial reference for research and prediction of engineering properties of saline soil.

关 键 词：盐渍土 土水特征曲线 颗粒分布曲线 预测模型 

分 类 号：P642.139[天文地球—工程地质学]