铁路路基粗粒土填料累积变形试验研究

Experimental Study on Accumulated Deformation of Coarse-grained Soil in Railway Subgrade

为了研究粗粒土路基在长期循环荷载作用下的累积变形规律,开展了一系列动三轴试验,分析了不同动应力比、围压及压实度对粗粒土累积变形的影响。研究结果表明:循环次数为1000次时的累积应变大约为总累积应变的75%,累积应变随着动应力比的增大而增大;当动应力比相同时,围压越大,累积应变越大;粗粒土累积应变随压实度的增大而减小,说明提高压实度能够有效抑制累积应变发展。基于试验结果,提出了能够反映动应力比、围压及压实度影响的粗粒土累积应变预测模型,与试验结果对比有较好的一致性,研究结果可铁路路基变形的预测提供参考依据。

In order to study accumulated deformation of coarse-grained soil in railway subgrade under long-term cyclic loading,a series of dynamic triaxial test was conducted,the effects of cycling stress ratio,confining pressure and compactness on accumulated deformation behavior were analyzed.The results show that the cumulative strain at 1000 cycles is approximately 75%of the total cumulative strain,and with increasing of cycling stress ratio,cumulative strain is increasing.When the cycling stress ratio is constant,the larger the confining pressure is,the larger the cumulative strain is.The cumulative strain of coarse-grained soil decrease with increase in compactness,so increase in compactness can effectively suppress development of cumulative strain.Based on test results,a cumulative strain predicting model of coarse-grained soil that can reflect the effects of cycling stress ratio,confining pressure and compactness is proposed,and it is in good agreement with the experimental results.This study can be served as reference for the accurate prediction of Railway Subgrade deformation.