京哈铁路路基冻结粉质黏土动剪切模量试验研究

Experimental investigation on dynamic shear modulus of frozen clay from subgrade of Beijing-Harbin Railway

以我国东北典型季节冻土区铁路路基为研究对象,针对季节性冻融路基轨道交通荷载的振动特点,采用室内低温动三轴试验方法,针对不同负温条件、加载频率、反复冻融条件设计室内试验工况,深入系统研究了京哈铁路王岗至双城段路基冻结粉质黏土的动力非线性本构关系、动剪切模量及其主要影响因素。研究表明,冻土、融土动应力–应变关系受负温、加载频率、冻融循环次数等因素影响,动剪切模量倒数与动应变之间具有明显的线性关系,表明京哈线粉质黏土应力应变关系符合双曲线模型。

The dynamic behavior of the frozen clay obtained from subgrade of Beijing-harbin Railway in northeast of China is investigated through cryo-dynamic triaxial experiments. The effects of several key factors including temperature, frequency and freeze–thaw cycles on the dynamic behavior are analyzed. Conclusions are drawn as follows: the reciprocal of dynamic shear modulus and dynamic strain is obviously in linear relationship. The dynamic stress-strain curve can be described by the Hardin–Drnevich hyperbolic model perfectly, and with the decrease of negative temperature and the increase of frequency the dynamic stress-strain curve are steeper. Freeze–thaw changes the structure of soils, the dynamic stress-strain curve is greatly different from that passing the first freeze–thaw cycle, and with the times of the freeze–thaw cycles, the property is steady.