非饱和黏性地基土一维压缩特性试验研究

Experimental Research on the One-dimensional Compression Characteristics of Unsaturated Cohesive Soil

研究目的:非饱和黏性土的压缩特性是路基工程、基础工程、地下工程以及边坡工程设计计算的重要参数。为研究基质吸力对非饱和土一维压缩特性的影响,本文以合肥地区非饱和黏性地基土为研究对象,进行基质吸力为常数、净竖向应力逐级增大的一维压缩试验。研究结论:(1)一维压缩变形下,不同基质吸力的e-lgp曲线均可以看作以净竖向应力300 k Pa为分界点的两条直线段;(2)压缩指数随基质吸力的变化关系符合Barcelona模型;压缩指数和切线压缩系数随基质吸力的增大呈指数衰减的变化规律;(3)为反映吸力对土体一维压缩变形的贡献,提出吸力切线压缩系数的概念,得到吸力切线压缩系数与净竖向应力之间呈现指数关系;(4)该成果可为研究黏性地基土的非饱和工程特性提供理论参考。

Research purposes： The compression characteristics of unsaturated cohesive soil is an important calculations calculations. In order to define the influence of matric suction on the one - dimensional compression characteristic, a series of one -dimensional compression tests are carried out under controlled matric suction and increasing the net vertical stress for the unsaturated cohesive foundation soil in Hefei area. Research conclusions： （ 1 ） The e - lgp curves in different matric suction were composed of two straight line segments, and the net vertical stress of 300 kPa was the cut - off point. （2） The relationship between compression index and the matric suction fitted the Barcelona model; Compression index and tangent compression coefficient decay exponentially with the increasing matric suction. （3）The concepts of suction tangent compression coefficient are proposed. The suction tangent compression coefficient showed exponential relationship with the net vertical stress. （4） The research result can provide theoretical reference to the engineering characteristics of the unsaturated cohesive soil bed.