干湿循环作用下水泥改良泥质板岩粗粒土动力特性

Dynamic Properties of Cement-improved Argillite-slate Coarse-grained Soil under Drying-wetting Cycles

为研究干湿循环作用对水泥改良泥质板岩粗粒土的动力稳定性影响,以标准养护龄期达28d的水泥改良泥质板岩粗粒土为试样,设计干湿循环条件下的改良土大型动三轴压缩试验.通过试验研究改良土动弹性模量、阻尼比和动应力强度等力学特征参数随干湿循环次数变化的规律,分析围压对干湿循环效应的影响,探讨干湿循环作用的影响机理.研究结果表明:1)随着干湿循环作用次数增加,最大动弹性模量和动强度均有所衰减,但衰减到一定程度后逐渐趋于稳定;2)最大阻尼比随着干湿循环作用次数增加而增加,但增加到一定程度后逐渐趋于稳定;3)干湿循环作用下,围压越大,最大动弹性模量和动强度的衰减幅度越小,最大阻尼比的增加幅度也越小.

In order to examine the influences of drying-wetting cycle on stability of cement-improved argillite-slate coarse-grained soil under dynamic loading, large-scale dynamic triaxial compression test on the soil at the standard curing age of 28 days was carried out.The mechanical characteristics parameters of improved soil, such as the change of dynamic elastic modulus, damping ratio and dynamic stress compres- sive strength with the drying-wetting cycles were studied by the tests.The influences of confining pressure on the dynamic properties under drying-wetting cycles were analyzed, and the influence mechanism of drying-wetting cycle was also discussed. The results indicate that. 1） Both the maximum dynamic elastic modulus and dynamic compressive strength decay with the drying-wetting cycles until they are tending to be stable.2） The maximum damping ratio increases with the drying-wetting cycles until it reaches stable value.3） Under the drying-wetting cycles, the attenuations of the dynamic elastic modulus and dynamic compressive strength of the improved soil decrease with the increase of confining pressure, while the increment of the damping ratio decreases with the increase of confining pressure.