冻融循环作用下原状过湿土的抗剪强度试验

为了研究季冻地区过湿土的抗剪强度特性,利用青冈过湿土路基段原状土进行抗剪强度试验,分析了不同含水量对过湿土的抗剪强度影响,重点研究了冻融循环作用下过湿土抗剪强度变化规律。试验结果表明:不同含水量的过湿土应力应变曲线均趋于硬化型,含水量越大,过湿土的抗剪强度越小,相应的内摩擦角和黏聚力也越小;同未冻融土相比,经冻融循环的过湿土黏聚力显著增加,内摩擦角减小;相同含水量的过湿土经冻融循环的次数越多,融化后土的抗剪强度越大,而且随着冻融次数的增多,黏聚力开始下降,内摩擦角显著增大。

SHEAR STRENGTH TEST OF UNDISTURBED OVER WET SOIL UNDER FREEZE-THAW CYCLES

In order to study the shear strength characteristics of over-wet soil in seasonal frozen area,the shear strength test of undisturbed soil in the subgrade of the Qinggang wetland was studied.The effects of different water contents on the shear strength of the wet soil are analyzed.The variation law of shear strength of over-wet soil under freezing-thawing cycle is studied emphatically.The experimental resuits show that the stress-strain curves of over-wet soils with different water contents tend to harden.The higher the water content,the smaller the shear strength of the over-wet soil,and the smaller the internal friction angle and cohesion.Compared with the unfrozen soil,the cohesion of the overburden in the freeze-thaw cycle increased significantly and the internal friction angle decreased.The more the number of times of the same moisture content of the wet soil through the freeze-thaw cycle,the greater the shear strength of the soil after melting,and with the increase of the number of freezing and thawing,the cohesion began to decline and the internal friction angle increased significantly.