间歇性循环荷载作用下细粒土的变形特性  

Deformation characteristics of fine-grained soil under cyclicdynamic loading with intermittence

作　　者：李亚峰 聂如松[1,2] 冷伍明[1,2] 程龙虎 梅慧浩[1] 董俊利 LI Ya-feng;NIE Ru-song;LENG Wu-ming;CHENG Long-hu;MEI Hui-hao;DONG Jun-li(School of Civil Engineering,Central South University,Changsha 410075,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学重载铁路工程结构教育部重点实验室,湖南长沙410075

出　　处：《浙江大学学报（工学版）》2020年第11期2109-2119,共11页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(51878666,51678572);中国铁路总公司系统性重大资助项目(P2018X011);中南大学研究生创新资助项目(2018zzts192).

摘　　要：铁路路基承受的列车动荷载作用由列车通过时产生的周期性振动和无列车通过时的加载间歇组成,针对此工程背景,开展不同围压、水的质量分数、动应力条件下的连续加载与加载-停振的动三轴试验,研究间歇性循环荷载作用下细粒土的超孔隙水压力、弹性应变、回弹模量和累积塑性应变的变化规律.试验结果表明,加载间歇对路基变形特性有显著影响.由于加载间歇阶段试样卸载以及排水作用,试样在加载阶段积累的超孔隙水压力在间歇阶段消散,土体内部颗粒及结构得到调整,试样抵抗后续荷载的能力得到提高.此外,加载间歇显著减缓了后续加载阶段的塑性应变发展,降低了试样的累积塑性应变.加载间歇对提高试样回弹模量、降低弹性应变的效果有限.加载-停振的间歇加载方式可以更准确地模拟实际列车荷载作用,进而获得更具实际意义的试验结果.In view of the fact that the dynamic train loading on the railway subgrade is the periodic vibration loading when the train passes and the intermittence when no train passes,a series of continuous and continuous-stopping vibration triaxial tests under different confining pressures,mass fractions of water and dynamic stress conditions were carried out to study the excess pore water pressure,elastic strain,resilience modulus and cumulative plastic strain of fine-grained soil under intermittent cyclic loading.Results show that the loading intermittence has a significant effect on the deformation characteristics of subgrade.Due to the unloading and drainage in the intermittent stage,the excess pore water pressure accumulated in the loading stage dissipates in the intermittent stage,and the particles and structure of the soil are also adjusted,thus the resistance of the samples to subsequent loading is improved.In addition,the intermittent stage significantly slows down the development of plastic strain in the subsequent loading stages and reduces the accumulated plastic strain of samples.However,the intermittent effect on improving the resilience modulus and reducing the elastic strain is limited.The continuous-stopping vibration can better simulate the actual train loads,and provides more practical test results.

关 键 词：细粒土填料 动三轴试验 间歇性循环荷载 变形特性 超孔隙水压力 

分 类 号：TU431[建筑科学—岩土工程]