华南典型路基红黏土动力学特性动三轴试验分析
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摘要
红黏土是华南地区典型的路基土类之一,其长期循环荷载作用下的动力学特性目前研究不多。利用室内动三轴试验,对4类重塑红黏土样的动应力应变关系、动应力累积效应、以及循环门槛应力比展开研究。研究结果表明:密实度对红黏土路基强度的影响远大于路基红黏土含水量的影响;正常运营条件下,长期车辆荷载导致的路基竖向变形与加载次数之间呈现稳定型关系,因此不会导致红黏土路基过度变形而诱发路基失稳等病害;华南地区红黏土反复荷载下其循环门槛应力比一般处于40%～50%之间,建议取值为45%。
Red clay is one of the most typical subgrade soils in Southern China. Studies on the dynamic characteristics of red clays are far from complete at the current stage. This study presents triaxial testing outcomes from 4 red clay samples focusing on dynamic stress-strain relationship,accumulation of dynamic stress,and threshold cyclic stress ratio under cyclic loading conditions. The results show that the influence of compactions on the shear strength of subgrade red clays is much stronger than that relating to variation of soil water content. Under normal operation conditions,the subgrade soil vertical settlement will be ultimately stabilized with increasing number of cyclic loading; as a result,the deformation will not be excessively large and induce instability of the subgrade and other relevant road hazards. The cyclic dynamic stress threshold of red clays in Southern China under repeated vehicle loading is about 40% to 50% of the maximum shear stress under static conditions; this study suggests 45% to be used in practice.
Red clay is one of the most typical subgrade soils in Southern China. Studies on the dynamic characteristics of red clays are far from complete at the current stage. This study presents triaxial testing outcomes from 4 red clay samples focusing on dynamic stress-strain relationship,accumulation of dynamic stress,and threshold cyclic stress ratio under cyclic loading conditions. The results show that the influence of compactions on the shear strength of subgrade red clays is much stronger than that relating to variation of soil water content. Under normal operation conditions,the subgrade soil vertical settlement will be ultimately stabilized with increasing number of cyclic loading; as a result,the deformation will not be excessively large and induce instability of the subgrade and other relevant road hazards. The cyclic dynamic stress threshold of red clays in Southern China under repeated vehicle loading is about 40% to 50% of the maximum shear stress under static conditions; this study suggests 45% to be used in practice.
引文
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[10]陈国兴,刘雪珠.循环荷载下南京片状细砂的动应力-应变关系[J].防灾减灾工程学报,2009,29(2):119-125.CHEN Guoxing,LIU Xuezhu. Dynamic stress-strain relationship of Nanjing flake-shaped sands in cyclic loading[J]. Journal of Disaster Prevention and Mitigation Engineering,2009,29(2):119-125.(in Chinese)
[11]王军,蔡袁强,徐长节,等.循环荷载作用下饱和软黏土应变软化模型研究[J].岩石力学与工程学报,2007,26(8):1713-1719.WANG Jun,CAI Yuanqiang,XU Changjie,et al. Study on strain softening model of saturated soft clay under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2007,26(8):1713-1719.(in Chinese)
[12]蔡袁强,柳伟,徐长节,等.基于修正Iwan模型的软黏土动应力-应变关系研究[J].岩土工程学报,2007,29(9):1314-1319.CAI Yuanqiang,LIU Wei,XU Changjie,et al. Study on dynamic stress-strain relationship of soft clay based on modified Iwan’s model under undrained cyclic loading[J]. Chinese Journal of Geotechnical Engineering,2007,29(9):1314-1319.(in Chinese)
[13]刘晓红,杨果林,方薇.红粘土动本构关系与动模量衰减模型[J].水文地质工程地质,2011,38(3):66-72.LIU Xiaohong,YANG Guoloin,FANG Wei. Dynamic constitutive relation and dynamic modulus attenuation model of red clay[J]. Hydrogeology&Engineering Geology,2011,38(3):66-72.(in Chinese)
[14]马林,张军,刘亚明.车辆荷载作用下山西路基重塑黄土的动力特性研究[J].地震工程学报,2018,40(1):101-104.MA Lin,ZHANG Jun,LIU Yaming. Study on the dynamic characteristics of remolded loess in shanxi expressway subgrade under vehicle loads[J]. China Earthquake Engineering Journal,2018,40(1):101-104.(in Chinese)
[15]周健,陈小亮,杨永香,等.饱和层状砂土液化特性的动三轴试验研究[J].岩土力学,2011,32(4):967-972,978.ZHOU Jian,CHEN Xiaoliang,YANG Yongxiang,et al. Study of liquefaction characteristics of saturated stratified sands by dynamic triaxial test[J]. Rock and Soil Mechanics,2011,32(4):967-972,978.(in Chinese)
[16]郑瑞华,张建民,张嘎,等.积石峡面板堆石坝材料大型三轴试验研究[J].岩土工程学报,2011,33(S1):177-181.ZHEN Ruihua,ZHANG Jianmin,ZHANG Ga,et al. Large-scale triaxial tests on rockfills of Jishixia CFRD[J]. Chinese Journal of Geotechnical Engineering,2011,33(S1):177-181.(in Chinese)
[17]田兆阳,李平,郑志华,等.软土动力特性动三轴试验研究[J].地震工程学报,2017,39(1):95-99,118.TIAN Zhaoyang,LI Ping,ZHENG Zhihua,et al. Dynamic triaxial tests on dynamic characteristics of soft soil[J]. China Earthquake Engineering Journal,2017,39(1):95-99,118.(in Chinese)
[18]姜岩,雷华阳,郑刚,等.循环荷载下结构性软土变形预测[J].交通运输工程学报,2011,11(1):13-18.JIANG Yan,LEI Huayang,ZHENG Gang,et al. Deformation prediction of structured soft clay under cyclic load[J]. Journal of Traffic and Transportation Engineering,2011,11(1):13-18.(in Chinese)
[19]高中南,周仲华,王峻,等.粉煤灰改良饱和黄土的抗液化特性[J].地震工程学报,2018,40(1):105-110.GAO Zhongnan,ZHOU Zhonghua,WANG Jun,et al. Anti-liquefaction properties of saturated loess improved by fly ash[J]. China Earthquake Engineering Journal,2018,40(1):105-110.(in Chinese)
[20]杨爱武,尚英杰,肖敏.先动后静荷载联合作用下结构性软粘土力学响应[J].自然灾害学报,2016(6):150-157.YANG Aiwu,SHANG Yingjie,XIAO Min. Mechanical response of structured soft clay under joint action of first dynamic and later static loads[J]. Journal of Natural Hazards,2016(6):150-157.(in Chinese)
[21] Xenaki V C,Athanasopoulos G A. Dynamic properties and liquefaction resistance of two soil materials in an earthfill dam-Laboratory test results[J]. Soil Dynamics and Earthquake Engineering,2008,28(8):605-620.
[22]宁行乐,肖宏彬,张春晓,等.膨胀土非线性蠕变模型研究[J].自然灾害学报,2017(1):149-155.NING Xingle,XIAO Hongbin,ZHANG Chunxiao,et al. Study on the nonlinear creep model of expansive soil[J]. Journal of Natural Hazards,2017(1):149-155.(in Chinese)
[23]黄博,丁浩,陈云敏.高速列车荷载作用的动三轴试验模拟[J].岩土工程学报,2011,33(2):195-202.HUANG Bo,DING Hao,CHEN Yunmin. Simulation of high-speed train load by dynamic triaxial tests[J]. Chinese Journal of Geotechnical Engineering,2011,33(2):195-202.(in Chinese)
[24] Matthew W F,Paul R F,Christopher D F R. Cyclic triaxial tests on clay subgrades for analytical pavement design[J]. Journal of Transportation Engineering,2004,130(3):378-386.
[25] Akke S J S,Emest T S,Raymond F. Static and cyclic triaxial testing of ballast and subballast[J]. Journal of Geotechnical and Geoenvironmental Engineering,2005,131(6):771-782.
[26] Li X W,Xian Zh L,Feng Zh,et al. CT scan on frozen roadbed soil under dynamic triaxial test condition of Beilu River section,Qinghai-Tibet Railway of China[C].//ICCTP 2009:Critical Issues in Transportation Systems Planning,Development,and Management,2009:942-950.
[27] Anand J P,Suppakit C,Ekarin W. Plastic deformation potentials of sandy clay from repeated load triaxial test[J]. Geotechnical Engineering for Transportation Projects,2004:938-947.
[28] Xiao J H,Guan Y B. Resilient behavior of compacted silt under the repeated triaxial test[C].//ICCTP 2010:Integrated Transportation SystemsGreen-Intelligent-Reliable,2010:3037-3045.
[29] Amir M K,Christian M,Peter Z. Ground vibration from high-speed trains:prediction and countermeasure[J]. Journal of Geotechnical and Geoenvironmental Engineering,2000,126(6),531-537.
[30]刘晓红,杨果林,方薇.短时动三轴试验与红粘土体积动剪应变门槛[J].工程勘察,2011,39(3):1-5.LIU Xiaohong,YANG Guolin,FANG Wei. Short-time cyclic triaxial tests and volume dynamic shear strain threshold of red clay[J]. Journal of Geotechnical Investigation&Surveying,2011,39(3):1-5.(in Chinese)
[2]汤连生,林沛元,吴科,等.交通荷载下层状路基动附加应力的弹性计算模型[J].岩石力学与工程学报,2009,28(11):2208-2214.TANG Liansheng,LIN Peiyuan,WU Ke,et al. Elastic calculation model for dynamic additional stresses in layered subgrade under traffic load[J]. Chinese Journal of Rock Mechanics and Engineering,2009,28(11):2208-2214.(in Chinese)
[3]汤连生,徐通,林沛元,等.交通荷载下层状道路系统动应力特征分析[J].岩石力学与工程学报,2009,28(S1):3876-3884.TANG Liansheng,XU Tong,LIN Peiyuan,et al. Studies on dynamic stress characteristics of layered road system under traffic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2009,28(S1):3876-3884.(in Chinese)
[4]汤连生,林沛元,吴科,等.单点动载下路基动应力状态及有效作用半径分析[J].岩石力学与工程学报,2011,30(2):4056-4063.TANG Liansheng,LIN Peiyuan,WU Ke,et al. Analysis of dynamic stress state and effective working radius in subgrade under concentrated load[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(2):4056-4063.(in Chinese)
[5]汤连生,林沛元,吴科,等.交通荷载下路基土中动应力响应特征分析[J].岩土工程学报,2011,33(11):1745-1749.TANG Liansheng,LIN Peiyuan,WU Ke,et al. Response characteristics of dynamic stress of subgrade soil under vehicle loads[J]. Chinese Journal of Geotechnical Engineering,2011,33(11):1745-1749.(in Chinese)
[6]陈晓平,黄国怡,梁志松.珠江三角洲软土特性研究[J].岩石力学与工程学报,2003,22(1):137-141.CHEN Xiaoping,HUANG Guoyi,LIANG Zhisong. Study on soft soil properties of the pearl river delta[J]. Chinese Journal of Rock Mechanics and Engineering,2003,22(1):137-141.(in Chinese)
[7]曾玲玲,陈晓平.软土在不同应力路径下的力学特性分析[J].岩土力学,2009,30(5):1264-1270.ZENG Lingling,CHEN Xiaoping. Analysis of mechanical characteristics of soft soil under different stress paths[J]. Rock and Soil Mechanics,2009,30(5):1264-1270.(in Chinese)
[8]周小文,陈凌伟,程展林,等.软基路堤施工稳定性控制标准研究[J].岩土力学,2016,37(9):2631-2635.ZHOU Xiaowen,CHEN Lingwei,CHEN Zhanlin,et al. Stability controlling standard for embankment construction on soft soil ground[J]. Rock and Soil Mechanics,2016,37(9):2631-2635.(in Chinese)
[9]刘添俊,莫海鸿.长期循环荷载作用下饱和软黏土的应变速率[J].华南理工大学学报:自然科学版,2008,36(10):37-42.LIU Tianjun,MO Haihong. Strain rate of saturated soft clay under long-term cyclic loading[J]. Journal of South China University of Technology:Natural Science Edition,2008,36(10):37-42.(in Chinese)
[10]陈国兴,刘雪珠.循环荷载下南京片状细砂的动应力-应变关系[J].防灾减灾工程学报,2009,29(2):119-125.CHEN Guoxing,LIU Xuezhu. Dynamic stress-strain relationship of Nanjing flake-shaped sands in cyclic loading[J]. Journal of Disaster Prevention and Mitigation Engineering,2009,29(2):119-125.(in Chinese)
[11]王军,蔡袁强,徐长节,等.循环荷载作用下饱和软黏土应变软化模型研究[J].岩石力学与工程学报,2007,26(8):1713-1719.WANG Jun,CAI Yuanqiang,XU Changjie,et al. Study on strain softening model of saturated soft clay under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2007,26(8):1713-1719.(in Chinese)
[12]蔡袁强,柳伟,徐长节,等.基于修正Iwan模型的软黏土动应力-应变关系研究[J].岩土工程学报,2007,29(9):1314-1319.CAI Yuanqiang,LIU Wei,XU Changjie,et al. Study on dynamic stress-strain relationship of soft clay based on modified Iwan’s model under undrained cyclic loading[J]. Chinese Journal of Geotechnical Engineering,2007,29(9):1314-1319.(in Chinese)
[13]刘晓红,杨果林,方薇.红粘土动本构关系与动模量衰减模型[J].水文地质工程地质,2011,38(3):66-72.LIU Xiaohong,YANG Guoloin,FANG Wei. Dynamic constitutive relation and dynamic modulus attenuation model of red clay[J]. Hydrogeology&Engineering Geology,2011,38(3):66-72.(in Chinese)
[14]马林,张军,刘亚明.车辆荷载作用下山西路基重塑黄土的动力特性研究[J].地震工程学报,2018,40(1):101-104.MA Lin,ZHANG Jun,LIU Yaming. Study on the dynamic characteristics of remolded loess in shanxi expressway subgrade under vehicle loads[J]. China Earthquake Engineering Journal,2018,40(1):101-104.(in Chinese)
[15]周健,陈小亮,杨永香,等.饱和层状砂土液化特性的动三轴试验研究[J].岩土力学,2011,32(4):967-972,978.ZHOU Jian,CHEN Xiaoliang,YANG Yongxiang,et al. Study of liquefaction characteristics of saturated stratified sands by dynamic triaxial test[J]. Rock and Soil Mechanics,2011,32(4):967-972,978.(in Chinese)
[16]郑瑞华,张建民,张嘎,等.积石峡面板堆石坝材料大型三轴试验研究[J].岩土工程学报,2011,33(S1):177-181.ZHEN Ruihua,ZHANG Jianmin,ZHANG Ga,et al. Large-scale triaxial tests on rockfills of Jishixia CFRD[J]. Chinese Journal of Geotechnical Engineering,2011,33(S1):177-181.(in Chinese)
[17]田兆阳,李平,郑志华,等.软土动力特性动三轴试验研究[J].地震工程学报,2017,39(1):95-99,118.TIAN Zhaoyang,LI Ping,ZHENG Zhihua,et al. Dynamic triaxial tests on dynamic characteristics of soft soil[J]. China Earthquake Engineering Journal,2017,39(1):95-99,118.(in Chinese)
[18]姜岩,雷华阳,郑刚,等.循环荷载下结构性软土变形预测[J].交通运输工程学报,2011,11(1):13-18.JIANG Yan,LEI Huayang,ZHENG Gang,et al. Deformation prediction of structured soft clay under cyclic load[J]. Journal of Traffic and Transportation Engineering,2011,11(1):13-18.(in Chinese)
[19]高中南,周仲华,王峻,等.粉煤灰改良饱和黄土的抗液化特性[J].地震工程学报,2018,40(1):105-110.GAO Zhongnan,ZHOU Zhonghua,WANG Jun,et al. Anti-liquefaction properties of saturated loess improved by fly ash[J]. China Earthquake Engineering Journal,2018,40(1):105-110.(in Chinese)
[20]杨爱武,尚英杰,肖敏.先动后静荷载联合作用下结构性软粘土力学响应[J].自然灾害学报,2016(6):150-157.YANG Aiwu,SHANG Yingjie,XIAO Min. Mechanical response of structured soft clay under joint action of first dynamic and later static loads[J]. Journal of Natural Hazards,2016(6):150-157.(in Chinese)
[21] Xenaki V C,Athanasopoulos G A. Dynamic properties and liquefaction resistance of two soil materials in an earthfill dam-Laboratory test results[J]. Soil Dynamics and Earthquake Engineering,2008,28(8):605-620.
[22]宁行乐,肖宏彬,张春晓,等.膨胀土非线性蠕变模型研究[J].自然灾害学报,2017(1):149-155.NING Xingle,XIAO Hongbin,ZHANG Chunxiao,et al. Study on the nonlinear creep model of expansive soil[J]. Journal of Natural Hazards,2017(1):149-155.(in Chinese)
[23]黄博,丁浩,陈云敏.高速列车荷载作用的动三轴试验模拟[J].岩土工程学报,2011,33(2):195-202.HUANG Bo,DING Hao,CHEN Yunmin. Simulation of high-speed train load by dynamic triaxial tests[J]. Chinese Journal of Geotechnical Engineering,2011,33(2):195-202.(in Chinese)
[24] Matthew W F,Paul R F,Christopher D F R. Cyclic triaxial tests on clay subgrades for analytical pavement design[J]. Journal of Transportation Engineering,2004,130(3):378-386.
[25] Akke S J S,Emest T S,Raymond F. Static and cyclic triaxial testing of ballast and subballast[J]. Journal of Geotechnical and Geoenvironmental Engineering,2005,131(6):771-782.
[26] Li X W,Xian Zh L,Feng Zh,et al. CT scan on frozen roadbed soil under dynamic triaxial test condition of Beilu River section,Qinghai-Tibet Railway of China[C].//ICCTP 2009:Critical Issues in Transportation Systems Planning,Development,and Management,2009:942-950.
[27] Anand J P,Suppakit C,Ekarin W. Plastic deformation potentials of sandy clay from repeated load triaxial test[J]. Geotechnical Engineering for Transportation Projects,2004:938-947.
[28] Xiao J H,Guan Y B. Resilient behavior of compacted silt under the repeated triaxial test[C].//ICCTP 2010:Integrated Transportation SystemsGreen-Intelligent-Reliable,2010:3037-3045.
[29] Amir M K,Christian M,Peter Z. Ground vibration from high-speed trains:prediction and countermeasure[J]. Journal of Geotechnical and Geoenvironmental Engineering,2000,126(6),531-537.
[30]刘晓红,杨果林,方薇.短时动三轴试验与红粘土体积动剪应变门槛[J].工程勘察,2011,39(3):1-5.LIU Xiaohong,YANG Guolin,FANG Wei. Short-time cyclic triaxial tests and volume dynamic shear strain threshold of red clay[J]. Journal of Geotechnical Investigation&Surveying,2011,39(3):1-5.(in Chinese)