温度对季冻区粉质黏土强度及变形特性的影响

为研究温度变化对天然状态及饱和状态下粉质黏土强度以及变形的影响,以典型季冻区广泛分布的粉质黏土为研究对象,通过GDS非饱和土三轴测试系统对天然状态下非饱和土以及GDS温控式静/动三轴测试系统对饱和粉质黏土,在不同温度条件下进行三轴试验。对试验结果进行研究分析可得：非饱和以及饱和粉质黏土的应力-应变曲线均呈现出应变硬化的特性。非饱和粉质黏土的黏聚力随温度降低表现出不断增加的趋势,而内摩擦角随温度降低逐渐减小,但整体变化趋势较小。饱和土的黏聚力与非饱和土变化趋势相同,随温度的降低其黏聚力逐渐增加,但相同温度时其黏聚力小于非饱和土,其内摩擦角则呈先减小后增加的转变趋势。无竖向压力作用时,相同围压条件下,非饱和与饱和粉质黏土轴向变形量随温度降低而增加,相同温度条件下,两者的轴向变形量随围压的增加会有所减小。试验成果可为季冻区粉质黏土地层工程的设计施工提供理论依据。

Study on the influence of temperature on the strength and deformation characteristics of silty clay in seasonal frozen area

In order to study the influence of temperature change on the strength and deformation of silty clay in natural state and saturated state, the silty clay widely distributed in typical seasonal frozen area is taken as the research object. The triaxial test of unsaturated soil in natural state and saturated silty clay under different temperature conditions is carried out by GDS unsaturated soil triaxial test system and GDS temperature-controlled static / dynamic triaxial test system. The experimental results show that the stress-strain curves of unsaturated and saturated silty clay show the characteristics of strain hardening. The cohesion of unsaturated silty clay increases with the decrease of temperature, while the internal friction angle decreases with the decrease of temperature, but the overall change trend is small. The cohesive force of saturated soil is the same as that of unsaturated soil. With the decrease of temperature, the cohesive force increases gradually, but the cohesive force is smaller than that of unsaturated soil at the same temperature, and the internal friction angle decreases first and then increases. When there is no vertical pressure, the axial deformation of unsaturated and saturated silty clay increases with the decrease of temperature under the same confining pressure, and the axial deformation of both decreases with the increase of confining pressure under the same temperature. The test results can provide theoretical basis for the design and construction of silty clay stratum engineering in seasonal frozen area.