黄土的构度指标及其试验确定方法

黄土的结构性是一个重要的物理性质指标,它与土的粒度、密度和湿度一起影响土的力学性质。依据加荷、扰动、浸水释放土结构势的方法,由土的无侧限抗压强度定义了黄土结构性的构度指标。通过多个场地不同黄土的无侧限单轴压缩试验,测试分析了不同含水率原状土、重塑土和饱和原状土的单轴压缩应力-应变曲线及无侧限抗压强度变化规律,由此得出土的构度指标的变化规律。并且,在粒度、密度、湿度相似条件下,比较分析了土的构度指标与其压缩性之间的关系。土的构度指标与粒度、密度和湿度指标一起能够合理描述土的物理力学基本性质。

Structural index of loess and its testing method

Loess structure is an important physical property, which influences mechanical properties of loess with its particle size, density and humidity. Based on the structure potential of loess released by loading, remolding and saturating, the unconfined compressive strength of intact, remolded and saturated loess were measured by uniaxial compression test; and the structural index of loess was defined by comparing the stability and changeability of loess structure which determined respectively by the ratio of confined compression strength of loess and remolding soil and the ratio of confined compressive strength of saturating loess and loess. Through the unconfined uniaxial compression test of four kinds of loess adopted from different sites, the unconfined uniaxial compression stress-strain curves of intact, remolded and saturated loesses with different water contents were tested to reflect the uniaxial compression stress-strain property, as well as the law of unconfined compressive strength and loess structural index changing with the water content was analyzed for different kinds of loesses. When the particle size, density and humidity of loess being similar, the greater the structure index of loess, the smaller the compressibility and the greater the shear strength of loess. So the structure Index structure together with the particle size, density and humidity can be used to describe reasonably the fundamental physico-mechanical properties of intact soils.