高速铁路路基粗粒土B组填料大型动三轴试验研究

LARGE-SCALE TRIAXIAL TEST STUDY ON SUBGRADE FILLER OF GROUP B-COARSE GRAINED SOIL OF HIGH SPEED RAILWAY

为研究高速铁路路基粗粒土B组填料的动弹性模量与阻尼特性,进行了大型动三轴试验。结果表明:动应变是影响粗粒土B组填料动弹性模量和阻尼比最主要的因素。随着动应变增大,动弹性模量呈幂指数减小、阻尼比呈S型曲线增加。随着固结围压或加载频率的增加,动弹性模量和阻尼比均增大。随着振动次数的增加,动弹性模量呈减小的趋势,应力水平越低衰减幅度越小。根据试验结果,建立了考虑围压、频率影响的动弹性模量及阻尼比关于动应变的关系模型,为高速铁路路基粗粒土B组填料的动力参数取值提供参考。

In order to study dynamic elastic modulus,damping ratio and its affecting facfors of subgrade filler of group B coarse grained soil for high speed railway,the consolidated undrained triaxial tests were carried out by large-scale trialxial test system.The results indicated that among many factors affecting dynamic modules and damping ratio, dynamic strain was the most important one.Dynamic modules decreased by exponent sign function and damping ratio increased by S-curve with the increasd of dynamic strain.Both dynamic modulus and damping ratio increased with the increase of confining pressure and loading frequency.Dynamic elastic modulus decreased with the increase of number of vibration, and the attenuation of dynamic elastic modulus increased when the dynamic stress level was high. According to the testing results, a model of both dynamic elastic modulus and damping ratio was established as a function of dynamic strain in consideration of confining pressure and frequency, which might provided reference for the dynamic parameters of coarse grained soil filler of subgrade of high speed railway.