基于离心模型试验的黄土高填方沉降影响因素分析
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摘要
使用复合型岩土离心试验机进行黄土高填方地基沉降模型试验,模拟沟谷地形中填筑体施工期和工后沉降过程,并系统研究黄土高填方沉降的影响因素。试验成果表明:施工速率、填方高度、沟谷形状、填筑压实度、时间等因素对填筑体沉降均存在影响。黄土高填方沉降主要发生在施工期,工后沉降所占比例较小。工后沉降随填方高度、时间对数均呈线性增长,工后沉降速率随时间呈指数衰减趋势。与开阔"U"型沟谷相比,狭窄"V"型沟谷地形对填方体有明显变形约束作用,沉降量小,稳定时间短。提高压实度、减小施工速率、控制填方高度均可减小填筑体沉降量,但提高压实度对大厚度填筑体的沉降控制作用更为显著,施工速率改变则对施工期沉降产生更直接的影响,填方高度与长期工后沉降量正相关关系则相对较为稳定。
Centrifuge model tests were performed to investigate the settlement of high loess-filled foundations in a valley during construction stage and in post-construction stage,and the influence factors on the settlement were discussed. Results illustrate that the settlement of the high loess-filled foundation is significantly affected by some factors such as the filling rate,filling height,valley shape,degree of compaction and time,and mainly occurs in the construction stage with a small proportion in the post-construction stage. The settlement in the post-construction stage increases linearly with the filling height and logarithmically with the time,while the post-construction settlement rate decreases exponentially with the time. Compared to the filled foundation in a U-shaped valley,the deformation of the loess-filled foundation in a narrow valley is evidently confined and as a result,the settlement is smaller and the time required to reach the stable state is shorter. A high compaction degree,a slow construction rate or a small filling height can reduce the settlement. Furthermore,the improvement of the compaction degree will be more significant for the settlement control of a thick filling body,the change of the construction rate directly affects the settlement of filled foundations in the construction stage,and there is a relatively stable positive correlation between the long-term post-construction settlement and the filling height.
Centrifuge model tests were performed to investigate the settlement of high loess-filled foundations in a valley during construction stage and in post-construction stage,and the influence factors on the settlement were discussed. Results illustrate that the settlement of the high loess-filled foundation is significantly affected by some factors such as the filling rate,filling height,valley shape,degree of compaction and time,and mainly occurs in the construction stage with a small proportion in the post-construction stage. The settlement in the post-construction stage increases linearly with the filling height and logarithmically with the time,while the post-construction settlement rate decreases exponentially with the time. Compared to the filled foundation in a U-shaped valley,the deformation of the loess-filled foundation in a narrow valley is evidently confined and as a result,the settlement is smaller and the time required to reach the stable state is shorter. A high compaction degree,a slow construction rate or a small filling height can reduce the settlement. Furthermore,the improvement of the compaction degree will be more significant for the settlement control of a thick filling body,the change of the construction rate directly affects the settlement of filled foundations in the construction stage,and there is a relatively stable positive correlation between the long-term post-construction settlement and the filling height.
引文
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[8]葛苗苗,李宁,郑建国,等.考虑黄土时效变形特性的高填方工后沉降预测[J].土木工程学报,2015,48(增2):262-267.(GEMiaomiao,LI Ning,ZHENG Jianguo,et al.Prediction of the post-construction settlement of high filled embankment with considering the time depending deformation of compacted loess[J].China Civil Engineering Journal,2015,48(Supp.2):262-267.(in Chinese))
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[13]郑建国,王婷,张继文.黄土路基沉降量预测方法的研究[J].岩土力学,2010,31(1):321-326.(ZHENG Jianguo,WANG Ting,ZHANG Jiwen.Study of settlement prediction methods of loess subgrade[J].Rock and Soil Mechanics,2010,31(1):321-326.(in Chinese))
[14]谭昌明,周建,黄广龙.多层软土地基沉降的分层迭代反演综合预测法[J].中国公路学报,2001,14(4):28-32.(TAN Changming,ZHOU Jian,HUANG Guanglong.Terative back-analysis layer by layer method to predict settlement of several layers soft clay ground[J].China Journal of Highway and Transport,2001,14(4):28-32.(in Chinese))
[15]吕庆,尚岳全,陈允法,等.高填方路堤黏弹性参数反演与工后沉降预测分析[J].岩石力学与工程学报,2005,24(7):1 231-1 235.(LU Qing,SHANG Yuequan,CHEN Yunfa,et al.Back-analysis of viscoelastic parameters of filling materials and settlement prediction for high filled embankment[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(7):1 231-1 235.(in Chinese))
[16]曹文贵,李鹏,程晔.高填石路堤蠕变本构模型及其参数反演分析与应用[J].岩土力学,2006,27(8):1 299-1 304.(CAOWengui,LI Peng,CHENG Ye.Study on constitutive model and its parameter’s back analysis of creep deformation for the high rock fill embankment and their application[J].Rock and Soil Mechanics,2006,27(8):1 299-1 304.(in Chinese))
[17]葛苗苗,李宁,张炜,等.黄土高填方沉降规律分析及工后沉降反演预测[J].岩石力学与工程学报,2017,36(3):745-753.(GEMiaomiao,LI Ning,ZHANG Wei,et al.Settlement behavior and inverse prediction of post construction settlement of high filled loess embankment[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(3):745-753.(in Chinese))
[18]刘守华,韩文喜,李景林,等.用离心模型研究超高填方地基变形特性[J].工程勘察,2005,(2):8-11.(LIU Shouhua,HAN Wenxi,LI Jinglin,et al.Research on settlement behaviors of high-filling foundation by using centrifuge model[J].Geotechnical Investigation and Surveying,2005,(2):8-11.(in Chinese))
[19]刘宏,张倬元,韩文喜.用离心模型试验研究高填方地基沉降[J].西南交通大学学报,2003,38(3):323-326.(LIU Hong,ZHANGZhuoyuan,HAN Wenxi.Centrifugal model tests for settlement of high embankment[J].Journal of Southwest Jiaotong University,2003,38(3):323-326.(in Chinese))
[20]景宏君,胡长顺,王秉纲.黄土高路堤沉降变形规律研究[J].岩石力学与工程学报,2005,24(增2):5 845-5 850.(JING Hongjun,HU Changshun,WANG Binggang.Study on settlement and deformation laws of high loess-fill embankment[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(Supp.2):5 845-5 850.(in Chinese))
[21]张军辉,黄湘宁,郑建龙,等.河池机场填石高填方土基工后沉降离心模型试验研究[J].岩土工程学报,2013,35(4):773-778.(ZHANG Junhui,HUANG Xiangning,ZHENG Jianlong,et al.Centrifugal model tests on post-construction settlement of high embankment of Hechi Airport[J].Chinese Journal of Geotechnical Engineering,2013,35(4):773-778.(in Chinese))
[22]曹杰,郑建国,张继文,等.不同边界条件下黄土高填方沉降离心模型试验[J].中国水利水电科学研究院学报,2017,15(4):256-262.(CAO Jie,ZHENG Jianguo,ZHANG Jiwen,et al.Centrifuge model tests of loess high-filled settlement under different boundary conditions[J].Journal of China Institute of Water Resources and Hydropower Research,2017,15(4):256-262.(in Chinese))
[23]田海,孔令伟,李波.降雨条件下松散堆积体边坡稳定性离心模型试验研究[J].岩土力学,2015,36(11):3 180-3 186.(TIANHai,KONG Lingwei,LI Bo.Centrifugal modeling tests on stability of deposits slope under rainfall[J].Rock and Soil Mechanics,2015,36(11):3 180-3 186.(in Chinese))
[2]朱才辉,李宁,刘明振,等.吕梁机场黄土高填方地基工后沉降时空规律分析[J].岩土工程报,2013,35(2):293-301.(ZHUCaihui,LI Ning,LIU Mingzhen,et al.Spatiotemporal laws of post-construction settlement of loess-filled foundation of Lüliang Airport[J].Chinese Journal of Geotechnical Engineering,2013,35(2):293-301.(in Chinese))
[3]何兆益,周虎鑫.高填方路堤填筑体沉降的三维有限元分析[J].重庆交通学院学报,2000,19(3):58-62.(HE Zhaoyi,ZHOU Huxin.3D finite element analysis of subsidence on high embankment[J].Journal of Chongqing Jiaotong Institute,2000,19(3):58-62.(in Chinese))
[4]李秀珍,许强,孔纪名,等.九寨黄龙机场高填方地基沉降的数值模拟分析[J].岩石力学与工程学报,2005,24(12):2 188-2 193.(LI Xiuzhen,XU Qiang,KONG Jiming,et al.Numerical modeling analysis of settlements of high fill foundation for Jiuzhai-Huanglong Airport[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(12):2 188-2 193.(in Chinese))
[5]吴俊,陈开圣,龙万学.高填方路基沉降变形有限元数值模拟[J].公路工程,2009,34(2):27-29.(WU Jun,CHEN Kaisheng,LONGWanxue.Numerical simulation in finite element of the sedimentation of high filled roadbed[J].Highway Engineering,2009,34(2):27-29.(in Chinese))
[6]宋二祥,曹光栩.山区高填方地基蠕变沉降特性及简化计算方法探讨[J].岩土力学,2012,33(6):1 712-1 718.(SONG Erxiang,CAOGuangxu.Characteristics and simplified calculation method of creep settlement of high fill foundation in mountain area[J].Rock and Soil Mechanics,2012,33(6):1 712-1 718.(in Chinese))
[7]黄雪峰,孔洋,李旭东,等.压实黄土变形特性研究与应用[J].岩土力学,2014,35(2):37-44.(HUANG Xuefeng,KONG Yang,LI Xudong,et al.Study and application of deformation characteristics of compacted loess[J].Rock and Soil Mechanics,2014,35(2):37-44.(in Chinese))
[8]葛苗苗,李宁,郑建国,等.考虑黄土时效变形特性的高填方工后沉降预测[J].土木工程学报,2015,48(增2):262-267.(GEMiaomiao,LI Ning,ZHENG Jianguo,et al.Prediction of the post-construction settlement of high filled embankment with considering the time depending deformation of compacted loess[J].China Civil Engineering Journal,2015,48(Supp.2):262-267.(in Chinese))
[9]朱才辉,李宁.基于黄土变形时效试验的高填方工后沉降研究[J].岩土力学,2015,36(10):3 023-3 031.(ZHU Caihui,LI Ning.Post-construction settlement analysis of loess-high filling based on time-dependent deformation experiments[J].Rock and Soil Mechanics,2015,36(10):3 023-3 031.(in Chinese))
[10]刘宏,李攀峰,张倬元.九寨黄龙机场高填方地基工后沉降预测[J].岩土工程学报,2005,27(1):90-93.(LIU Hong,LI Panfeng,ZHANG Zhuoyuan.Prediction of the post-construction settlement of the high embankment of Jiuzhai-Huanglong airport[J].Chinese Journal of Geotechnical Engineering,2005,27(1):90-93.(in Chinese))
[11]杨涛,戴济群,李国维.基于指数法的分级填筑路堤沉降预测方法研究[J].土木工程学报,2005,38(5):92-95.(YANG Tao,DAIJiqun,LI Guowei.Settlement prediction of stage-constructed embankment on soft ground using the exponent fitting method[J].China Civil Engineering Journal,2005,38(5):92-95.(in Chinese))
[12]王丽琴,靳宝成,杨有海.黄土路堤工后沉降预测新模型与方法[J].岩石力学与工程学报,2007,26(11):2 370-2 376.(WANG Liqin,JIN Baocheng,YANG Youhai.New model and method for forecasting post-construction settlement of loess-fill embankments[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(11):2 370-2 376.(in Chinese))
[13]郑建国,王婷,张继文.黄土路基沉降量预测方法的研究[J].岩土力学,2010,31(1):321-326.(ZHENG Jianguo,WANG Ting,ZHANG Jiwen.Study of settlement prediction methods of loess subgrade[J].Rock and Soil Mechanics,2010,31(1):321-326.(in Chinese))
[14]谭昌明,周建,黄广龙.多层软土地基沉降的分层迭代反演综合预测法[J].中国公路学报,2001,14(4):28-32.(TAN Changming,ZHOU Jian,HUANG Guanglong.Terative back-analysis layer by layer method to predict settlement of several layers soft clay ground[J].China Journal of Highway and Transport,2001,14(4):28-32.(in Chinese))
[15]吕庆,尚岳全,陈允法,等.高填方路堤黏弹性参数反演与工后沉降预测分析[J].岩石力学与工程学报,2005,24(7):1 231-1 235.(LU Qing,SHANG Yuequan,CHEN Yunfa,et al.Back-analysis of viscoelastic parameters of filling materials and settlement prediction for high filled embankment[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(7):1 231-1 235.(in Chinese))
[16]曹文贵,李鹏,程晔.高填石路堤蠕变本构模型及其参数反演分析与应用[J].岩土力学,2006,27(8):1 299-1 304.(CAOWengui,LI Peng,CHENG Ye.Study on constitutive model and its parameter’s back analysis of creep deformation for the high rock fill embankment and their application[J].Rock and Soil Mechanics,2006,27(8):1 299-1 304.(in Chinese))
[17]葛苗苗,李宁,张炜,等.黄土高填方沉降规律分析及工后沉降反演预测[J].岩石力学与工程学报,2017,36(3):745-753.(GEMiaomiao,LI Ning,ZHANG Wei,et al.Settlement behavior and inverse prediction of post construction settlement of high filled loess embankment[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(3):745-753.(in Chinese))
[18]刘守华,韩文喜,李景林,等.用离心模型研究超高填方地基变形特性[J].工程勘察,2005,(2):8-11.(LIU Shouhua,HAN Wenxi,LI Jinglin,et al.Research on settlement behaviors of high-filling foundation by using centrifuge model[J].Geotechnical Investigation and Surveying,2005,(2):8-11.(in Chinese))
[19]刘宏,张倬元,韩文喜.用离心模型试验研究高填方地基沉降[J].西南交通大学学报,2003,38(3):323-326.(LIU Hong,ZHANGZhuoyuan,HAN Wenxi.Centrifugal model tests for settlement of high embankment[J].Journal of Southwest Jiaotong University,2003,38(3):323-326.(in Chinese))
[20]景宏君,胡长顺,王秉纲.黄土高路堤沉降变形规律研究[J].岩石力学与工程学报,2005,24(增2):5 845-5 850.(JING Hongjun,HU Changshun,WANG Binggang.Study on settlement and deformation laws of high loess-fill embankment[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(Supp.2):5 845-5 850.(in Chinese))
[21]张军辉,黄湘宁,郑建龙,等.河池机场填石高填方土基工后沉降离心模型试验研究[J].岩土工程学报,2013,35(4):773-778.(ZHANG Junhui,HUANG Xiangning,ZHENG Jianlong,et al.Centrifugal model tests on post-construction settlement of high embankment of Hechi Airport[J].Chinese Journal of Geotechnical Engineering,2013,35(4):773-778.(in Chinese))
[22]曹杰,郑建国,张继文,等.不同边界条件下黄土高填方沉降离心模型试验[J].中国水利水电科学研究院学报,2017,15(4):256-262.(CAO Jie,ZHENG Jianguo,ZHANG Jiwen,et al.Centrifuge model tests of loess high-filled settlement under different boundary conditions[J].Journal of China Institute of Water Resources and Hydropower Research,2017,15(4):256-262.(in Chinese))
[23]田海,孔令伟,李波.降雨条件下松散堆积体边坡稳定性离心模型试验研究[J].岩土力学,2015,36(11):3 180-3 186.(TIANHai,KONG Lingwei,LI Bo.Centrifugal modeling tests on stability of deposits slope under rainfall[J].Rock and Soil Mechanics,2015,36(11):3 180-3 186.(in Chinese))