Long term settlement of railroad silt subgrade induced by train loading
XIAO Jun-hua1,2, ZHOU Shun-hua2, WEI Kai3
1. College of Transportation and Engineering, Nanjing University of Technology, Nanjing 210009, China;
2. Key Laboratory of Road and Traffic Engineering, Ministry of Education, Tongji University, Shanghai 201804, China;
3. State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
The prediction models of resilient modulus and accumulative deformation were obtained based on the triaxial test results of silt subgrade soil under repeated loads. The dynamic stress of railroad silt subgrade induced by train loading was analyzed through dynamic finite element analysis and field measurements. A computational procedure of longterm settlement of railroad silt subgrade was proposed. The influences of train speed, axle load, number of load repetitions, and parameters of ballast and subgrade on the longterm settlement of subgrade were analyzed. If the rail track is seriously irregular and the subgrade compacting factor is very low, the longterm settlement of railroad silt subgrade linearly increases with the train speed, and gradually grows with the number of load repetitions, especially in conditions of high axle load and low subgrade compacting factor. At low compacting factor, the settlement of silt subgrade significantly reduces with increasing ballast thickness or subgrade compacting factor. Moreover, there is a threshold influence depth of the longterm settlement of railroad silt subgrade subjected to train loading, and the lower subgrade compacting factor, the deeper influence depth.
［1］ 中华人民共和国铁道部行业标准.TB100012005,铁路路基设计规范［S］.北京: 中国铁道出版社, 2005.
Occupation standard of Ministry of Railways of PRC. TB100012005, Code for design on subgrade of railway ［S］. Beijing: China railway press, 2005.
［2］ 肖军华.提速列车荷载下粉土的力学响应与路基稳定性研究［D］.北京:北京交通大学, 2008.
XIAO Junhua. Study on the dynamic properties of silt and subgrade stability subjected to train moving loading ［D］. Beijing: Beijing Jiaotong University, 2008.
［3］ 肖军华,刘建坤,彭丽云,等.黄河冲积粉土的干密度及含水率对力学性质影响［J］.岩土力学,2008,29(2): 409414.
XIAO Junhua, LIU Jiankun, PENG Liyun, et al. Effect of dry density and moisture content on behaviors of YellowRiver alluvial silt ［J］. Rock and Soil Mechanics, 2008, 29(2): 409-414.
［4］ 肖军华,刘建坤.循环荷载下粉土路基土的变形性状［J］.中国铁道科学,2010,31(1): 18. XIAO Junhua, LIU Jiankun. Deformation behaviors of silt subgrade soil under repeated loading ［J］. China Railway Science, 2010, 31(1): 1-8.
［5］ LIU Jiankun, XIAO Junhua. Experimental study on the stability of railroad silt subgrade with increasing train speed ［J］. Journal of Geotechnical and Geoenvironmental Engineering, 2010, 136(6): 833-841.
［6］ MONISMITH C L, OGAWA N, FREEME C R. Permanent deformation characteristics of subgrade soils due to repeated loading ［C］∥ Transportation Research Record 537. Washington DC: Transportation Research Board, 1975: 1-17.
［7］ 铁道科学研究院.既有线提速200 km/h非改建地段试验报告［R］.北京:铁道科学研究院,2006.
Chinese Academy of Railway Science. Measurements of subgrade dynamic responses on Chinese existing railway with train moving at speed of 200 km/h ［R］. Beijing: Chinese Academy of Railway Science, 2006.
［8］ 王其昌.高速铁路土木工程［M］.成都:西南交通大学出版社,1999: 301-329.
［9］ 王金昌,陈页开.ABAQUS在土木工程中的应用［M］.杭州:浙江大学出版社,2006: 42-78.
［10］ 梁波,蔡英.不平顺条件下高速铁路路基的动力分析［J］.铁道学报,1999,21(2): 84-88.
LIANG Bo, CAI Ying. Dynamic analysis on subgrade of high speed railways in geometric irregular condition ［J］. Journal of China Railway Society, 1999, 21(2): 84-88.
［11］ LI D Q, SELIG E T. Accumulative plastic deformation for finegrained subgrade soil ［J］. Journal of Geotechnical Engineering, 1996, 122(12): 1006-1013.
［12］ 马伟斌,史存林,张千里,等.循环载荷作用下基床力学特性对道床影响的动态模型试验研究［J］.铁道学报,2006,28(4): 102-108.
MA Weibin, SHI Cunlin, ZHANG Qianli, et al. Dynamic model experimental study on effects of mechanical properties of railway subgrade beds on ballast beds under cyclic loading ［J］. Journal of China Railway Society, 2006, 28(4): 102-108.
