列车振动荷载作用下南京细砂振动累积变形特性试验研究  

EXPERIMENTAL ANALYSIS ON DYNAMIC CUMULATIVE DEFORMATION OF NANJING FINE SAND UNDER TRAIN-INDUCED VIBRATION LOADING

作　　者：庄海洋[1] 陈磊[2] 沈礼伟 左玉峰[1] 

机构地区：[1]南京工业大学岩土工程研究所,南京210009 [2]江苏省交通规划设计院股份有限公司,南京210005

出　　处：《工程地质学报》2014年第6期1294-1300,共7页Journal of Engineering Geology

基　　金：江苏省自然科学基金青年项目(SBK201241288);江苏省研究生科研创新计划项目(CXLX12_0436)资助

摘　　要：列车振动荷载作用下松散砂土振密造成的早期路基沉降将对列车的正常运行产生很大的影响。本文以南京地区新近沉积片状细砂为研究对象,采用英国GDS空心圆柱扭剪仪模拟列车振动荷载的实际应力路径,并考虑排水条件、试样围压和加载幅值等因素,初步研究了2000列次(14000振次)列车振动荷载作用下南京新近沉积片状细砂的振动排水特性和竖向累积变形特性。实验结果表明,试样围压对南京片状细砂的竖向累积变形的影响较为明显,同时,当试验围压较小时,加载幅值对试样的竖向累积变形的影响更大。其次,排水条件主要对列车运营前期的路基累积变形产生明显的影响,对后期的累积变形的影响基本可以忽略。最后,根据试验结果,本文也初步给出了排水条件和不排水条件下南京片状细砂的竖向累积应变增长曲线的新预测公式及其参数取值。研究结论对列车振动荷载作用下新近沉积砂性土的动力学特性及其累积变形的计算方法等问题的研究具有很好的参考价值。The earlier settlement of railway roadbed caused by train-induced vibration loading has great effects on the train driving safety if loose sand layers are included in the railway foundation.Accordingly,the GDS triaxial hollow cylindrical multi-function apparatus is used to model the real stress path of the train-induced vibration loading.The tested fine sand is distributed in Nanjing area,near to Yangtze rive.Its dynamic deformation properties are studied by taking into consideration of the drain condition and the confining pressure and the load amplitude.As results,the confining pressure has a greater effect on the vertical accumulated deformation of the test samples.The＆nbsp;amplitude of vibration loading has a greater effect on the vertical accumulated deformation if the confining pressure is smaller.Also,the drain condition has a greater effect on the earlier settlement of roadbed than on the later settlement.At the same time,the new formulas and its parameters are developed and can be used to predict the vertical accumulated deformation of Nanjing fine sand with flake-shape structure.They are given based on the test results.These research conclusions can be used to predict the long-term settlement of railway roadbed with the newly deposited fine sand included in roadbed.

关 键 词：列车振动荷载 南京细砂 累积变形 振动孔压 土动力学 

分 类 号：U213.1[交通运输工程—道路与铁道工程]