成都东郊膨胀土强度与含水率关系的试验研究

Test Study on Chengdu Expansive Soils Strangth Parameters with Water Contents

成都东郊地区膨胀土极为发育,在天然条件下土体强度较高,但在土体遇水后强度会急剧降低,由可塑~硬塑状迅速变为流塑状。由于对成都膨胀土强度参数认识不足,出现了不少的基坑、边坡失稳等问题。针对上述问题通过在一膨胀土基坑内取原状样进行直剪试验,对试验数据进行整理分析发现：成都膨胀土黏聚力c与内摩擦角均随含水率的增加而降低,且均有良好的线性关系;并在此基础上建立成都膨胀土强度参数与含水率关系的经验公式,对基坑工程中膨胀土强度参数取值方法提出建议。

Expansive soil is very developmental in the east suburb of Chengdu region. The soil strength is higher under the natural condition,but the strength will reduce sharply after the soil under water and change from plastic or hard plastic shape rapidly to plastic flow. Owing to a lack of understanding of Chengdu expansive soil strength parameters,a lot of problems such as foundation pit and slope in-stability appear. According to the above problems through within a expansive soil deformation of foundation pit to take the original samples to do direct shear test,the test data for sorting analysis is found that Chengdu expansive soil cohesive force and internal friction angle decrease with increasing water content,and has good linear relationship. Based on the test,Chengdu expansive soils＇ empirical formula between the strength parameters and water contents is built,the strength of expansive soil in the excavation engineering parameter selection method is proposed.