基于土拱效应的桩网结构路基稳定性可靠度分析
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摘要
基于路基土拱效应的应力集中现象,并考虑荷载及土体参数的变异性,建立了桩网结构路基稳定性的可靠度计算模型,给出了可靠度分析的计算方法及流程。以某一典型高速公路桩网结构路基进行稳定性分析为例,分别利用安全系数法和可靠度方法设计了该桩网结构路基加固桩长度,并基于荷载及土体参数变异性,对可靠度指标进行了敏感性分析,结果表明:荷载及土体参数的变异性对桩网结构路基的稳定性影响显著,利用可靠度方法来计算桩网结构路基加固桩长度的设计更为安全和合理;需要特别注意第二层土的极限侧阻力及路基面附加荷载变异性的影响,而路基填料内摩擦角及加固桩极限端阻力可当作常量来处理。
Based on the phenomenon of stress concentration induced by the soil arching effect and the variability of loads and soil parameters,a model for reliability analysis of stability evaluation of the pile-supported embankment was built,and the reliability index calculation method and flow chart were presented in this paper. Taking a typical pile-supported embankment of a highway as an example for stability analysis,the reinforced pile length for the embankment was designed with the safety factor method and reliability index method,respectively,and sensitivity analysis of the reliability index was conducted based on the variability of loads and soil parameters. The results show that the variability of loads and soil parameters has a large influence on the stability of the pile-supported embankment,and it is more reliable and reasonable to use the reliability index method to design the reinforced pile length. The results also indicate that the limit lateral resistance of the second-layer soil and the variability of additional loads on the embankment surface should be given close attention,and the internal friction angle of embankment filling and the ultimate resistance of the reinforced pile can be treated as constants.
Based on the phenomenon of stress concentration induced by the soil arching effect and the variability of loads and soil parameters,a model for reliability analysis of stability evaluation of the pile-supported embankment was built,and the reliability index calculation method and flow chart were presented in this paper. Taking a typical pile-supported embankment of a highway as an example for stability analysis,the reinforced pile length for the embankment was designed with the safety factor method and reliability index method,respectively,and sensitivity analysis of the reliability index was conducted based on the variability of loads and soil parameters. The results show that the variability of loads and soil parameters has a large influence on the stability of the pile-supported embankment,and it is more reliable and reasonable to use the reliability index method to design the reinforced pile length. The results also indicate that the limit lateral resistance of the second-layer soil and the variability of additional loads on the embankment surface should be given close attention,and the internal friction angle of embankment filling and the ultimate resistance of the reinforced pile can be treated as constants.
引文
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[15]高谦.土木工程可靠性理论及其应用[M].北京:中国建材工业出版社,2007:57-66.
[16]中国铁路总公司.铁路路基极限状态设计暂行规范(试行):Q/CR 9127—2015[S].北京:中国铁道出版社,2014.
[2]宗国庆,蒋慧.真空(堆载)预压法在高速公路软土地基处理中的应用[J].水利水电科技进展,2002,22(6):41-43.(ZONG Guoqing,JIANG Hui.Consolidation of soft foundations with vacuum preloading method[J].Advances in Science and Technology of Water Resources,2002,22(6):41-43.(in Chinese))
[3]许小健,干洪,张金轮.沉降预测广义Usher模型参数确定的优化算法[J].水利水电科技进展,2010,30(5):73-76.(XU Xiaojian,GAN Hong,ZHANG Jinlun.Optimization algorithms for parameters of generalized Usher model of settlement prediction[J].Advances in Science and Technology of Water Resources,2010,30(5);73-76.(in Chinese))
[4]孙新彪.高速铁路CFG桩复合地基承载特性研究[D].成都:西南交通大学,2009.
[5]曹卫平,陈仁朋,陈云敏.桩承式加筋路堤土拱效应试验研究[J].岩土工程学报,2007,29(3):431-437.(CAO Weiping,CHEN Renpeng,CHEN Yunmin.Experimantal investigation on soil arching in piled reinforced embankments[J].Chinese Journal of Geotechnical Engineering,2007,29(3):431-437.(in Chinese))
[6]TEZAGHI K.Theoretical soil mechanics[M].New York:John Wiley&Sons,1943.
[7]魏永幸,薛新华.无砟轨道桩-网结构路基设计方法研究[J].高速铁路技术,2010,1(1):22-26.(WEI Yongxing,XUE Xinhua.Design method of pile-net composition foundation of ballastless track[J].High Speed Railway Technology,2010,1(1):22-26.(in Chinese))
[8]蒋鑫,凌建明,谭炜,等.高速公路填砂路基边坡稳定性分析[J].铁道工程学报,2008(9):1-6.(JIANG Xin,LING Jianming,TAN Wei,et al.Slope stability analysis of sand embankment for expressway engineering[J].Journal of Railway Engineering Society,2008(9):1-6.(in Chinese))
[9]蒋水华,李典庆,周创兵,等.考虑参数空间变异性的非饱和土坡可靠度分析[J].岩土力学,2014,35(9):2569-2578.(JIANG Shuihua,LI Dianqing,ZHOU Chuangbing,et al.Reliability analysis of unsaturated slope considering spatial variability[J].Rock and Soil Mechanics,2014,35(9):2569-2578.(in Chinese))
[10]梁燕,李家春,李萍,等.考虑洪水大小随机性的路基抗冲刷可靠度评价[J].公路交通科技,2013,30(1):50-55.(LIANG Yan,LI Jiachun,LI Ping,et al.Evaluation of subgrade reliability in erosion of flood considering uncertainty of flood volume[J].Journal of Highway and Transportation Research and Development,2013,30(1):50-55.(in Chinese))
[11]龚文惠,姜友生,王元汉.膨胀土路基沉降的模糊可靠度[J].岩土力学,2004,25(8):1340-1342.(GONG Wenhui,JIANG Yousheng,WANG Yuanhan.Fuzzy reliability for settlement of expansive soil roadbed[J].Rock and Soil Mechanics,2004,25(8):1340-1342.(in Chinese))
[12]EBGEO.Empfehlungen für den entwurf und die berechnung von erdkorpern mit bewehrungen aus geokunststoffen[M].Berlin:German Geotechnical Society,2010.
[13]van EEKELEN S J M,BEZUIJEN A,LODDER H J,et al.Model experiments on piled embankments:partⅡ[J].Geotextiles and Geomembranes,2012,32:82-94.
[14]吴坤铭,王建国,谭晓慧.基于可靠度分析确定刚性抗滑桩锚固深度[J].岩土工程学报,2012,34(2):237-242.(WU Kunming,WANG Jianguo,TAN Xiaohui.Determination of anchorage depth for rigid anti-slide piles based on reliability analysis[J].Chinese Journal of Geotechnical Engineering,2012,34(2):237-242.(in Chinese))
[15]高谦.土木工程可靠性理论及其应用[M].北京:中国建材工业出版社,2007:57-66.
[16]中国铁路总公司.铁路路基极限状态设计暂行规范(试行):Q/CR 9127—2015[S].北京:中国铁道出版社,2014.