冻融循环对黏土强度的影响试验研究

Experimental study on effect of freeze-thaw cycle on strength of clay

为了研究冻融作用对黏土强度及渗透性的影响,在不同冻融次数条件下,开展黏土的直接剪切试验、无侧限抗压强度试验及渗透试验,研究黏土的摩擦角、黏聚力、无侧限抗压强度和渗透系数随冻融次数的变化规律。结果表明:冻融作用使得黏土内部孔隙和水分迁移通道扩展,导致黏土渗透性显著增大;黏土的结构性随着冻融循环次数的增加而不断劣化,使其黏聚力和内摩擦角随冻融循环次数增加而呈现下降趋势;黏土的无侧限抗压强度均随冻融循环次数的增加而逐渐减小,最终趋于稳定;1~4次的冻融循环对黏土强度和渗透性的影响较大,冻融循环次数继续增加时其影响逐渐减小。

In order to study the effect of freeze-thaw on strength and permeability of clays,direct shear tests,unconfined compressive strength tests and permeability tests were carried out on clays under different freeze-thaw times.The friction Angle,cohesion force,unconfined compressive strength and permeability coefficient of clays were studied with different freeze-thaw times.The results show that the freeze-thaw process expands the internal pores and water migration channels of clay,resulting in a significant increase in clay permeability.The structure of clay deteriorates with freeze-thaw cycles,and the cohesion and internal friction Angle decrease with the increase of the number of freeze-thaw cycles.The unconfined compressive strength of clay decreases gradually with the increase of the number of freeze-thaw cycles,and finally tends to be stable.The effect of one to four freeze-thaw cycles on the strength and permeability of clay is great,and the effect gradually decreases as the number of freeze-thaw cycles increases.