季节性冰冻地区路基土动态回弹模量试验研究

Experimental study on dynamic resilient modulus of subgrade soil in seasonal frozen area

为研究季节性冰冻地区路基土的动态特性,采用动态三轴压缩试验对路基土动态回弹模量进行研究。分析了位于内蒙古东部季节性冰冻地区的2种典型路基土质在不同应力状态、不同含水率条件以及不同冻融循环次数下的路基动态回弹模量变化规律,并推荐了2种典型路基土质的动态回弹模量取值范围。试验结果表明:在一定的应力范围内,动态回弹模量随着围压的增加而增大,随着偏应力的降低而减小,并且围压对动态回弹模量的影响程度高于偏应力;含水率及冻融循环均对动态回弹模量产生重要影响,且影响程度与土质类型及冻融循环次数有关。试验中选取的赤峰黄土动态回弹模量取值范围为80~100 MPa,冻融循环折减系数为0.76;通辽砂土动态回弹模量取值范围为90~120 MPa,冻融循环折减系数为0.87。研究结果可为该地区的路面结构设计提供参考。

In order to study the dynamic characteristics of subgrade soil in seasonal frozen area,dynamic triaxial compression test was used to study the dynamic resilient modulus of subgrade soil.The dynamic resilient modulus of two typical subgrade soils was analyzed in the east of Inner Mongolia under different stress states,different moisture content conditions and different freeze-thaw cycles.The value range of dynamic resilient modulus of two typical subgrade soils was recommended.The test results show that the dynamic resilient modulus increases with the increase of confining pressure,and decreases with the decrease of deviating stress in a certain stress range.The influence degree of confining pressure on dynamic resilient modulus is higher than deviating stress.Water content and freeze-thaw cycle have an important impact on the production of dynamic resilient modulus,and the influence degree is related to the type of soil and the number of freeze-thaw cycles.The dynamic resilient modulus of Chifeng loess is 80-100 MPa,and the reduction coefficient of freeze-thaw cycle is 0.76.The dynamic resilient modulus of Tongliao sand is 90-120 MPa,and the reduction coefficient of freeze-thaw cycle is 0.87.The research results can provide reference for the design of pavement structure in this region.