冻土动强度特性试验研究

Dynamic strength of frozen soils

在围压为0.3～16 MPa,频率为2 Hz,温度为-4和-6℃条件下,通过一系列恒应力幅循环动荷载试验,发现冻土动强度的变化不仅跟破坏振次的大小有关,而且与围压、循环荷载作用下土体吸收的有效能量(损失能)之间也存在一定关系。根据损失能获得试样温度的变化,将冻土动强度与温度直接联系起来,表明振动荷载作用下损失能累积造成的温度额外升高是控制冻土动强度变化特性的主要因素之一。

Dynamic strength characteristics of frozen silty clay was studied using triaxial cycle tests with the constant stress amplitude under confuting pressures varying between 0.3 MPa and 16.0 MPa, at temperatures of -4℃ and -6℃ and a frequency of 2 Hz. It was shown that the dynamic strength depended not only on the number of vibrations and confining pressures, but also on loss of energy resulted from cyclic loading. According to the relationship among the dynamic strength, loss of energy and variation of temperature in specimens, an approximate formula was obtained, indicating that the loss of dynamic strength was influenced by confining pressures and the loss of energy. Thus, one of the key factors controlling the dynamic strength was the raised temperature resulted from the accumulative energy under cyclic loading.