原状黄土的结构性及其与变形特性关系研究

Research on relationship between structure and deformation property of intact loess

在不同含水率下对兰州、西安原状黄土进行压缩试验,根据同一压力下原状、重塑及饱和黄土的孔隙比定义了一个定量结构性参数,探讨了结构性参数随压力及含水率变化的规律性。研究表明:(1)用结构性参数随含水率及压力变化特性来研究结构性对原状黄土的压缩性、湿陷性的影响可以得到良好的规律性。(2)同一含水率下结构性参数在压力未达到结构强度以前,随压力的增大而增大;达到结构强度之后,压力增大使结构性参数明显减小或缓慢增大。(3)同一压力下结构性参数在含水率未达到结构破坏起始含水率ωf之前降低很小;达到ωf之后,含水率增大,使结构性参数快速减小。ωf随压力的增大而减小,高压力处含水率变化对结构性参数有显著影响。(4)两地黄土在不同压力或含水率下湿陷系数与结构性参数mp关系可以归一为一条直线,即湿陷系数受结构性影响的规律是相同的。

The compression tests are conducted on Lanzhou and Xi＇an intact loess under different water contents. The quantitative comprehensive structural parameter is defined by using void ratio of intact, disturbed and saturated loess. The effects of water content and pressure on the structural parameter are investigated. The study indicates. （1） The better relationship between deformation characteristics （compressibility and collapsibility） and structure can be obtained by using the variation characteristics of the structural parameter of intact loess with the change of water content and pressure. （2） Under the same water content, the structure parameter increases with the increase of pressure before structure strength; and it decreases or scarcely increases after it. （3） Under the same pressure, the structure parameter scarcely decreases with the increase of water content before the initial structure destruction water content wf; and it apparently decreases after it. wr decreases with the increase of pressure. The change of water content has obvious effect on the structure parameter.（4） The relationship between coefficient of collapsibility and the structural parameter almost is the same line for intact loess in two regions under different pressures and water contents.