基于Mesri蠕变模型的路基工后沉降计算方法研究
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摘要
路基工后沉降直接关乎铁路行车安全性及乘车舒适性,对工后沉降的可靠预测一直是工程界所追求的目标。本文基于Mesri蠕变模型理论引入路基荷载下受路基宽高比影响的附加竖向应力解析式,提出了一种天然地基条件下路基工后沉降计算方法。与依赖前期沉降观测资料的预测方法不同,本文方法适用性更为广泛,且具有模型参数少、物理意义明确、易于获取以及适合计算机编程等优点。通过与离心模型试验对比,路基工后沉降的计算值与离心机数据吻合较好,计算结果具有较高精度,验证了计算方法的可行性。经过对比发现,在铺轨完成后约2a,路基沉降逐渐趋于收敛,此时的沉降占工后总沉降的80%以上。研究成果可为初步设计阶段路基工后沉降预测提供一种简便算法,具有一定工程意义。
Post-construction settlement of railway embankment,the reliable prediction of which is always pursued by the engineering circle,is directly related to traffic safety and ride comfort.Based on the theory of Mesri creep model incorporating analytical equations of additional vertical stress under embankment load subject to the width-height ratio of the embankment,a calculation method for post-construction settlement in natural ground was proposed.The method is suited for computer programming with the advantages of fewer model parameters,definite physical meaning and easy accessibility.Unlike the other methods dependent on previous settlement observation data,the proposed method is wider in applicability.Compared with the centrifuge model tests,the good agreement between calculation values of post-construction settlements and test data,as well as high accuracy,validated the feasibility of the computational approach.By contrast,the settlements of the embankment converged gradually about 2 years after the completion of track-laying.During the two-year period,the settlements accounted for 80%of total post-construction ones.The research results have certain engineering significance for providing a simple calculation method for predicting post-construction settlement in the preliminary design stage.
Post-construction settlement of railway embankment,the reliable prediction of which is always pursued by the engineering circle,is directly related to traffic safety and ride comfort.Based on the theory of Mesri creep model incorporating analytical equations of additional vertical stress under embankment load subject to the width-height ratio of the embankment,a calculation method for post-construction settlement in natural ground was proposed.The method is suited for computer programming with the advantages of fewer model parameters,definite physical meaning and easy accessibility.Unlike the other methods dependent on previous settlement observation data,the proposed method is wider in applicability.Compared with the centrifuge model tests,the good agreement between calculation values of post-construction settlements and test data,as well as high accuracy,validated the feasibility of the computational approach.By contrast,the settlements of the embankment converged gradually about 2 years after the completion of track-laying.During the two-year period,the settlements accounted for 80%of total post-construction ones.The research results have certain engineering significance for providing a simple calculation method for predicting post-construction settlement in the preliminary design stage.
引文
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[10]蒋关鲁,王海龙,李安洪,等.土质路基荷载下地基反力试验研究[J].铁道学报,2012,34(6):69-74.JIANG Guanlu,WANG Hailong,LI Anhong et al.Experimental Study on Ground Reaction under Subgrade[J].Journal of the China Railway Society,2012,34(6):69-74.
[11]蒋关鲁,王力伟,杭红星.路桥交界处地基附加应力修正计算方法[J].岩土工程学报,2013,35(2):208-218.JIANG Guanlu,WANG Liwei,HANG Hongxing.The Modified Additional Stress Calculation Method of Bridge Approach Foundation under the Subgrade Load[J].Chinese Journal of Geotechnical Engineering,2013,35(2):208-218.
[12]肖东,蒋关鲁,林展展,等.过渡段地基加固作用对桥台桩工作性状的影响分析[J].中南大学学报(自然科学版),2017,48(3):820-829.XIAO Dong,JIANG Guanlu,LIN Zhanzhan,et al.Analysis of Working Properties of Abutment Piles Considering Foundation Reinforcement of Approach Embankment[J].Journal of Central South University(Science and Technology),2017,48(3):820-829.
[13]国家铁路局.TB 10621—2014高速铁路设计规范[S].北京:中国铁道出版社,2014.
[14]JAN K,ALESSANDRO P.Proposal of the Boltzmannlike Superposition Principle from Nonlinear Tensile Creep of the Thermoplastics[J].Ploymer Testing,2008,27:596-606.
[15]FENG S Y,WEI L M,HE C Y,et al.A Computational Method for Post-construction Settlement of High-speed Railway Bridge Pile Foundation Considering Soil Creep Effect[J].Journal of Central South University,2014,21(7):2921-2927.
[16]李安洪,蒋关鲁,王智猛,等.中等压缩性土地基沉降特性及加固技术研究总报告[R].成都:中铁二院工程集团有限责任公司,2012.
[2]殷宗泽.土工原理[M].北京:中国水利水电出版社,2007.
[3]陈善雄,王星运,许锡昌,等.铁路客运专线路基沉降预测的新方法[J].岩土力学,2010,31(2):478-482.CHEN Shanxiong,WANG Xingyun,XU Xichang,et al.New Method for Forecasting Subgrade Settlement of Railway Passenger Dedicated Line[J].Rock and Soil Mechanics,2010,31(2):478-482.
[4]MESRI G,FEBRESCORDERO E,SHEILDS D R,et al.Shear Stress-strain-time Behaviour of Clays[J].Geotechnique,1981,31(4):537-552.
[5]张崇磊.中等压缩性土地区短桩桩网复合地基路基荷载传递规律及沉降机理研究[D].成都:西南交通大学,2015.
[6]陈善雄,王小刚,姜领发,等.铁路客运专线路基面沉降特征与工程意义[J].岩土力学,2010,31(3):702-706.CHEN Shanxiong,WANG Xiaogang,JIANG Lingfa,et al.Settlement Characteristics and Engineering Significance of Subgrade Surface for Railway Passenger Dedicated Line[J].Rock and Soil Mechanics,2010,31(3):702-706.
[7]SINGH A,MITCHELL J K.General Stress-strain-time Function for Soils[J].Journal of the Soil Mechanics and Foundations Division,1968,94(1):21-46.
[8]KONDNER R L.Hyperbolic Stress-strain Response:Cohesive Soils[J].Journal of Soil Mechanics and Foundation Division,ASCE,1963,89(1):115-143.
[9]李军世,孙钧.上海淤泥质黏土的Mesri蠕变模型[J].土木工程学报,2001,34(6):74-79.LI Junshi,SUN Jun.Mesri Creep Model for Shanghai Siltclay[J].China Civil Engineering Journal,2001,34(6):74-79.
[10]蒋关鲁,王海龙,李安洪,等.土质路基荷载下地基反力试验研究[J].铁道学报,2012,34(6):69-74.JIANG Guanlu,WANG Hailong,LI Anhong et al.Experimental Study on Ground Reaction under Subgrade[J].Journal of the China Railway Society,2012,34(6):69-74.
[11]蒋关鲁,王力伟,杭红星.路桥交界处地基附加应力修正计算方法[J].岩土工程学报,2013,35(2):208-218.JIANG Guanlu,WANG Liwei,HANG Hongxing.The Modified Additional Stress Calculation Method of Bridge Approach Foundation under the Subgrade Load[J].Chinese Journal of Geotechnical Engineering,2013,35(2):208-218.
[12]肖东,蒋关鲁,林展展,等.过渡段地基加固作用对桥台桩工作性状的影响分析[J].中南大学学报(自然科学版),2017,48(3):820-829.XIAO Dong,JIANG Guanlu,LIN Zhanzhan,et al.Analysis of Working Properties of Abutment Piles Considering Foundation Reinforcement of Approach Embankment[J].Journal of Central South University(Science and Technology),2017,48(3):820-829.
[13]国家铁路局.TB 10621—2014高速铁路设计规范[S].北京:中国铁道出版社,2014.
[14]JAN K,ALESSANDRO P.Proposal of the Boltzmannlike Superposition Principle from Nonlinear Tensile Creep of the Thermoplastics[J].Ploymer Testing,2008,27:596-606.
[15]FENG S Y,WEI L M,HE C Y,et al.A Computational Method for Post-construction Settlement of High-speed Railway Bridge Pile Foundation Considering Soil Creep Effect[J].Journal of Central South University,2014,21(7):2921-2927.
[16]李安洪,蒋关鲁,王智猛,等.中等压缩性土地基沉降特性及加固技术研究总报告[R].成都:中铁二院工程集团有限责任公司,2012.