循环荷载下桩网结构路基和垫层动力响应研究
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摘要
基于相似理论,开展了4组桩网结构路基大比例动态模型试验,测试了循环荷载下桩网结构路基的动力响应指标,研究了降雨前、后加载力、加载频率以及循环加载次数对路基的动力响应、桩土荷载分担以及垫层格栅应变的影响。结果表明,降雨后路基动应力和动加速度均会增大,并且在基床内部增速较快,而路堤下部其增长基本趋于稳定;循环加载期间桩土应力比缓慢增大,其受降雨影响敏感,雨后降幅可达56.4%~79.5%;循环加载完成后垫层格栅应变增大,其横向分布特征基本保持不变;土拱形成后路基填高继续增加,路基宽度范围内4桩中心格栅应变增幅较大,峰值出现在边坡中心和路基中心附近,横向分布呈"W"型;两桩中心的格栅应变由路基中心向坡脚处呈"台阶"型递增,而路基宽度与边坡范围的格栅应变差距不断缩小。
Four large-scale model tests are made to monitor the dynamic response of column-net structure subgrade. The influence of loading level, loading frequency and loading times on the dynamic parameters, the pile-soil load sharing and the strains of geogrid are studied. The results show that the dynamic stress and the dynamic acceleration increase fast in the bed of subgrade and underneath trend towards stability with depth after rainfall. During the stage of cyclic loading, the stress concentration ratio increases slowly. After rainfall, the stress concentration ratio can decrease about 56.4 % to 79.5 %. Compared with the construction stage, the strains of geogrid increase and the transverse distributions remain the same form after cyclic loading. The strains of geogrid among four piles within the width of subgrade increase fast after the formation of soil arching. The peak value points of strains of geogrid appear in the centre of the slope and subgrade, which emerges as W-shape in the cross-section. The strains of geogrid between two piles increase from the centre to the slope toe of subgrade, which emerges as stair-shape. The differences of strains of geogrid between the slope and the width of subgrade decrease gradually after the formation of soil arching.
Four large-scale model tests are made to monitor the dynamic response of column-net structure subgrade. The influence of loading level, loading frequency and loading times on the dynamic parameters, the pile-soil load sharing and the strains of geogrid are studied. The results show that the dynamic stress and the dynamic acceleration increase fast in the bed of subgrade and underneath trend towards stability with depth after rainfall. During the stage of cyclic loading, the stress concentration ratio increases slowly. After rainfall, the stress concentration ratio can decrease about 56.4 % to 79.5 %. Compared with the construction stage, the strains of geogrid increase and the transverse distributions remain the same form after cyclic loading. The strains of geogrid among four piles within the width of subgrade increase fast after the formation of soil arching. The peak value points of strains of geogrid appear in the centre of the slope and subgrade, which emerges as W-shape in the cross-section. The strains of geogrid between two piles increase from the centre to the slope toe of subgrade, which emerges as stair-shape. The differences of strains of geogrid between the slope and the width of subgrade decrease gradually after the formation of soil arching.
引文
[1]肖宏,蒋关鲁,魏永幸,等.遂渝线无碴轨道桩网结构地基处理技术[J].铁道工程学报,2006,94(4):22-25.XIAO Hong,JIANG Guan-lu,WEI Yong-xing,et al.Discussion of Sui-Yu railway line ballastless track column-net structure[J].Journal of Railway Engineering Society,2006,94(4):22-25.
[2]周镜,叶阳升,蔡德钩.国外加筋垫层桩支承路基计算方法分析[J].中国铁道科学,2007,28(2):1-6.ZHOU Jing,YE Yang-sheng,CAI De-gou.Analysis of calculation method for foreign geosynthetic reinforced pile supported embankments[J].China Railway Science,2007,28(2):1-6
[3]HEWLETT W J,RANDOLPH M F.Analysis of piled embankments[J].Ground Engineering,1988,21(3):12
[4]LOW B K,TANG S K,CHO A.Arching in piled embankments[J].Journal of Geotechnical Engineering,1994,120(11):1917-1938.
[5]陈云敏,贾宁,陈仁朋.桩承式路堤土拱效应分析[J].中国公路学报,2004,17(4):1-6.CHEN Yun-min,JIA Ning,CHEN Ren-peng.Soil arch analysis of pile-supported embankments[J].China Journal of Highway and Transport,2004,17(4):1-6.
[6]陈福全,李阿池.桩承式加筋路堤的改进设计方法研究[J].岩土工程学报,2007,29(12):1804-1808.CHEN Fu-quan,LI A-chi.Improved design method of geosynthetic reinforced pile supported embankments on soft soil[J].Chinese Journal of Geotechnical Engineering.2007,29(12):1804-1808.
[7]曹新文,卿三惠,周立新.桩网复合地基土工格栅加筋效应的试验研究[J].岩石力学与工程学报,2006,25(1):3162-3167.CAO Xin-wen,QING San-hui,ZHOU Li-xin.Experimental study on reinforcement effect of geogrid on composite foundation with dry jet mixing piles[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(1):3162-3167.
[8]张良,罗强,陈亚美,等.桩网结构路基承载特性的现场试验研究[J].岩土力学,2010,31(12):3793-3800.ZHANG Liang,LUO Qiang,CHEN Ya-mei,et al.Research on bearing behavior of pile-net structure subgrade based on field test[J].Rock and Soil Mechanics,2010,31(12):3793-3800.
[9]PHU-DOANH Bui,罗强,张良,等.基于大比例静力模型试验的高强度桩复合地基加筋垫层分析[J].岩土工程学报,2012,34(12):2345-2349.PHU-DOANH Bui,LUO Qiang,ZHANG Liang,et al.Analysis of reinforced cushions in high-strength concrete pile composite foundation based on large-scale static model tests[J].Chinese Journal of Geotechnical Engineering,2012,34(12):2345-2349.
[10]蔡德钩,闫宏业,叶阳升,等.桩网支承路基结构中土拱效应及网垫受力的模型试验研究[J].铁道学报,2011,33(11):85-92.CAI De-gou,YAN Hong-ye,YE Yang-sheng,et al.Model study on arch effect and bedding force of geosynthetics reinforced and pile supported embankment[J].Journal of the China Railway Society,2011,33(11):85-92.
[11]于进江,程谦恭,贺宏武,等.超大面积深厚软土桩-网复合地基承载性状模型试验研究[J].岩土力学,2012,33(11):3323-3330.YU Jin-jiang,CHENG Qian-gong,HE Hong-wu,et al.Model test research on bearing behavior of pile-net composite foundation on oversized deep soft soil[J].Rock and Soil Mechanics,2012,33(11):3323-3330.
[12]陈仁朋,徐正中,陈云敏.桩承式加筋路堤关键问题研究[J].中国公路学报,2007,20(2):7-12.CHEN Ren-peng,XU Zheng-zhong,CHEN Yun-min.Research on key problems of pile supported reinforced embankment[J].China Journal of Highway and Transport,2007,20(2):7-12.
[13]肖宏,蒋关鲁,魏永幸,等.客运专线无碴轨道桩网结构模型试验研究[J].铁道学报,2007,29(2):126-131.XIAO Hong,JIANG Guan-lu,WEI Yong-xing,et al.Model test of column-net structure for express passenger line unballasted track[J].Journal of the China Railway Society,2007,29(2):126-131.
[14]肖宏,蒋关鲁,魏永幸.桩网结构模型试验柔性拱研究[J].岩土力学,2008,29(11):3032-3036.XIAO Hong,JIANG Guan-lu,WEI Yong-xing.Study of flexible arch of model test in column-net structure[J].Rock and Soil Mechanics,2008,29(11):3032-3036.
[15]肖宏,蒋关鲁,魏永幸.遂渝线无砟轨道桩网结构路基现场动车试验测试分析[J].铁道学报,2010,32(1):79-84.XIAO Hong,JIANG Guan-lu,WEI Yong-xing.Dynamic test analysis on ballastless-track column-net structure subgrade of the Suining-Chongqing railway line[J].Journal of the China Railway Society,2010,32(1):79-84.
[16]王智猛,蒋关鲁,魏永幸,等.达成线红层泥岩路基循环加载试验研究[J].岩土工程学报,2008,30(12):1888–1893.WANG Zhi-meng,JIANG Guan-lu,WEI Yong-xing,et al.Experimental study on dynamic performance of redmudstone subgrade under cyclic loading in DazhouChengdu line[J].Chinese Journal of Geotechnical Engineering,2008,30(12):1888–1893.
[2]周镜,叶阳升,蔡德钩.国外加筋垫层桩支承路基计算方法分析[J].中国铁道科学,2007,28(2):1-6.ZHOU Jing,YE Yang-sheng,CAI De-gou.Analysis of calculation method for foreign geosynthetic reinforced pile supported embankments[J].China Railway Science,2007,28(2):1-6
[3]HEWLETT W J,RANDOLPH M F.Analysis of piled embankments[J].Ground Engineering,1988,21(3):12
[4]LOW B K,TANG S K,CHO A.Arching in piled embankments[J].Journal of Geotechnical Engineering,1994,120(11):1917-1938.
[5]陈云敏,贾宁,陈仁朋.桩承式路堤土拱效应分析[J].中国公路学报,2004,17(4):1-6.CHEN Yun-min,JIA Ning,CHEN Ren-peng.Soil arch analysis of pile-supported embankments[J].China Journal of Highway and Transport,2004,17(4):1-6.
[6]陈福全,李阿池.桩承式加筋路堤的改进设计方法研究[J].岩土工程学报,2007,29(12):1804-1808.CHEN Fu-quan,LI A-chi.Improved design method of geosynthetic reinforced pile supported embankments on soft soil[J].Chinese Journal of Geotechnical Engineering.2007,29(12):1804-1808.
[7]曹新文,卿三惠,周立新.桩网复合地基土工格栅加筋效应的试验研究[J].岩石力学与工程学报,2006,25(1):3162-3167.CAO Xin-wen,QING San-hui,ZHOU Li-xin.Experimental study on reinforcement effect of geogrid on composite foundation with dry jet mixing piles[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(1):3162-3167.
[8]张良,罗强,陈亚美,等.桩网结构路基承载特性的现场试验研究[J].岩土力学,2010,31(12):3793-3800.ZHANG Liang,LUO Qiang,CHEN Ya-mei,et al.Research on bearing behavior of pile-net structure subgrade based on field test[J].Rock and Soil Mechanics,2010,31(12):3793-3800.
[9]PHU-DOANH Bui,罗强,张良,等.基于大比例静力模型试验的高强度桩复合地基加筋垫层分析[J].岩土工程学报,2012,34(12):2345-2349.PHU-DOANH Bui,LUO Qiang,ZHANG Liang,et al.Analysis of reinforced cushions in high-strength concrete pile composite foundation based on large-scale static model tests[J].Chinese Journal of Geotechnical Engineering,2012,34(12):2345-2349.
[10]蔡德钩,闫宏业,叶阳升,等.桩网支承路基结构中土拱效应及网垫受力的模型试验研究[J].铁道学报,2011,33(11):85-92.CAI De-gou,YAN Hong-ye,YE Yang-sheng,et al.Model study on arch effect and bedding force of geosynthetics reinforced and pile supported embankment[J].Journal of the China Railway Society,2011,33(11):85-92.
[11]于进江,程谦恭,贺宏武,等.超大面积深厚软土桩-网复合地基承载性状模型试验研究[J].岩土力学,2012,33(11):3323-3330.YU Jin-jiang,CHENG Qian-gong,HE Hong-wu,et al.Model test research on bearing behavior of pile-net composite foundation on oversized deep soft soil[J].Rock and Soil Mechanics,2012,33(11):3323-3330.
[12]陈仁朋,徐正中,陈云敏.桩承式加筋路堤关键问题研究[J].中国公路学报,2007,20(2):7-12.CHEN Ren-peng,XU Zheng-zhong,CHEN Yun-min.Research on key problems of pile supported reinforced embankment[J].China Journal of Highway and Transport,2007,20(2):7-12.
[13]肖宏,蒋关鲁,魏永幸,等.客运专线无碴轨道桩网结构模型试验研究[J].铁道学报,2007,29(2):126-131.XIAO Hong,JIANG Guan-lu,WEI Yong-xing,et al.Model test of column-net structure for express passenger line unballasted track[J].Journal of the China Railway Society,2007,29(2):126-131.
[14]肖宏,蒋关鲁,魏永幸.桩网结构模型试验柔性拱研究[J].岩土力学,2008,29(11):3032-3036.XIAO Hong,JIANG Guan-lu,WEI Yong-xing.Study of flexible arch of model test in column-net structure[J].Rock and Soil Mechanics,2008,29(11):3032-3036.
[15]肖宏,蒋关鲁,魏永幸.遂渝线无砟轨道桩网结构路基现场动车试验测试分析[J].铁道学报,2010,32(1):79-84.XIAO Hong,JIANG Guan-lu,WEI Yong-xing.Dynamic test analysis on ballastless-track column-net structure subgrade of the Suining-Chongqing railway line[J].Journal of the China Railway Society,2010,32(1):79-84.
[16]王智猛,蒋关鲁,魏永幸,等.达成线红层泥岩路基循环加载试验研究[J].岩土工程学报,2008,30(12):1888–1893.WANG Zhi-meng,JIANG Guan-lu,WEI Yong-xing,et al.Experimental study on dynamic performance of redmudstone subgrade under cyclic loading in DazhouChengdu line[J].Chinese Journal of Geotechnical Engineering,2008,30(12):1888–1893.