青藏铁路北麓河段路基冻土特性的实验研究

Experimental study on subgrade permafrost characteristics along Qinghai-tibet railway in Beiluhe section

为降低列车荷载对冻土路基的影响,以青藏铁路北麓河段路基粉质黏土为研究对象,制作重塑土样,在室内进行低温动三轴实验,分析温度、围压及速率效应对冻土骨干曲线和冻土动强度的影响。结果表明:冻土骨干曲线形态接近双曲线,不同实验条件下的骨干曲线与Hardin双曲线拟合结果的标准误差小于0.12;冻土动强度随温度的降低而上升,随围压、频率的升高而升高;相对于围压和频率,温度对骨干曲线和动强度的影响最大。该研究可以为工程设计和施工提供科学依据。

This paper is aimed at reducing the impact of train load on the permafrost subgrade. The research building on the subgrade silty clay in the Beiluhe section of Qinghai-tibet railway involves making the remolded soil samples; performing the low temperature dynamic triaxial experiment indoors; and thereby analyzing the effects of temperature,confining pressure and velocity influence of fracture curves and frozen soil strength on permafrost. The results show that the permafrost has the shape of the backbone curve close to that of the hyperbola; there is the standard error of less than 0. 12 in the fitting result between the backbone curve and the Hardin hyperbolic curve under different experimental conditions; the dynamic strength of the frozen soil increases with the decrease of the temperature and increases with the rise of confining pressure and frequency; and relative to confining pressure and frequency,temperature exerts the greatest effect on the backbone curve and dynamic strength. This research can provide a scientific basis for engineering design and construction.