反复冻融条件下黄土边坡稳定性分析
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摘要
春季冻土融化导致黄土地区边坡冻融灾害频繁发生,因对其机理性研究的不足,目前对此尚不能进行量化分析和预测。本文首先对西安Q3原状黄土进行室内冻融试验,研究冻融作用对其剪切强度的影响;其次,基于室内试验数据,运用有限元强度折减法对黄土边坡冻融失稳特征进行数值计算分析。研究发现:黄土试样粘聚力随冻融次数增加呈指数衰减趋势;粘聚力随含水率增加表现出线性衰减特征且冻融后粘聚力与含水率的变化曲线近似重合;内摩擦角无明显规律性变化。黄土边坡安全系数随冻融次数增加亦呈指数衰减趋势,这与粘聚力随冻融次数的变化规律是一致的;安全系数随冻融深度和冻融区初始含水率增加显著减小且降低幅度逐渐增加;安全系数随坡度系数和放坡级数增加近似呈线性增加特征。黄土边坡冻融滑裂面与季节冻融深度线近似重合。
The thawing of frozen soils in spring has caused the frequent freezing-thawing disaster for slope in loess regions. Moreover,the disaster can't be quantitatively analyzed and predicted,which is induced by the weak mechanism research. Based on that,the paper firstly carried out freeze-thaw test to study the influence of freeze-thaw action on the shear strength of xi'an Q3 undisturbed loess. The results show that the cohesion of loess exponentially decreases with freezing and thawing times increasing. With the increase of water content,the cohesion linearly decreases,and has a approximately same variation after freezing and thawing. The internal friction angle has no obvious variation during the whole freezing-thawing process. The safety factor of loess slope also exponentially decreases with freezing and thawing times increasing,which is corresponding with the relationship between the cohesion and freezing-thawing times. With the increase of the freezing-thawing depth and water content in active layer,the safety factor decreases with a growing gradient. The safety factor linearly increases with the increase of slope coefficient and sloping steps. The freeze-thaw slip surface of the loess slope is approximately consistent with the seasonal freeze-thaw depth line.
The thawing of frozen soils in spring has caused the frequent freezing-thawing disaster for slope in loess regions. Moreover,the disaster can't be quantitatively analyzed and predicted,which is induced by the weak mechanism research. Based on that,the paper firstly carried out freeze-thaw test to study the influence of freeze-thaw action on the shear strength of xi'an Q3 undisturbed loess. The results show that the cohesion of loess exponentially decreases with freezing and thawing times increasing. With the increase of water content,the cohesion linearly decreases,and has a approximately same variation after freezing and thawing. The internal friction angle has no obvious variation during the whole freezing-thawing process. The safety factor of loess slope also exponentially decreases with freezing and thawing times increasing,which is corresponding with the relationship between the cohesion and freezing-thawing times. With the increase of the freezing-thawing depth and water content in active layer,the safety factor decreases with a growing gradient. The safety factor linearly increases with the increase of slope coefficient and sloping steps. The freeze-thaw slip surface of the loess slope is approximately consistent with the seasonal freeze-thaw depth line.
引文
[1]刘祖典.黄土力学与工程[M].西安:陕西科学技术出版社出版发行,1996.LIU Zudian.Loess mechanics and engineering[M].Xi’an:Shanxi Science and Technology Press,1996.
[2]许领,戴福初,邝国麟,等.黄土滑坡典型工程地质问题分析[J].岩土工程学报,2009,31(2):288-292.XU Ling,DAI Fuchu,KUANG Guolin,et al.Analysis of some special engineering-geological problems of loess landslide[J].Chinese Journal of Geotechnical Engineering,2009,31(2):288-292.
[3]刘悦,黄强兵.黄土路堑边坡开挖变形机理的离心模型试验研究[J].水文地质工程地质,2007,34(3):59-62.LIU Yue,HUANG Qiangbing.Centrifuge model test on the deformation mechanism of loess cut slope[J].Hydrogeology&Engineering Geology,2007,34(3):59-62.
[4]李荣建,郑文,刘军定,等.考虑初始结构性参数的结构性黄土边坡稳定性评价[J].岩土力学,2014,35(1):144-150.LI Rongjian,ZHENG Wen,LIU Junding,et al.Evaluation of stability of structural loess slope considering initial structural parameters[J].Rock and Soil Mechanics,2014,35(1):144-150.
[5]周泓,张泽,秦琦,等.冻融循环作用下黄土基本物理性质变异性研究[J].冰川冻土,2015,37(1):162-168.ZHOU Hong,ZHANG Ze,QIN Qi,et al.Research onvariability of basic physical properties of loess under freezing-thawing cycles[J].Journal of Glaciology and Geocryology,2015,37(1):162-168.
[6]叶万军,杨更社,彭建兵,等.冻融循环导致洛川黄土边坡剥落病害产生机制的试验研究[J].岩石力学与工程学报,2012,31(1):199-205.YE Wanjun,YANG Gengshe,PENG Jianbing,et al.Test research on mechanism of freezing-thawing cycle resulting in loess slope spalling hazards in luochuan[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(1):199-205.
[7]王铁行,罗少锋,刘小军.考虑含水率影响的非饱和原状黄土冻融强度试验研究[J].岩土力学,2010,31(8):2378-2382.WANG Tiehang,LUO Shaofeng,LIU Xiaojun.Testing study of freezing-thawing strength of unsaturated undisturbed loess considering influence of moisture content[J].Rock and Soil Mechanics,2010,31(8):2378-2382.
[8]穆彦虎,马巍,李国玉,等.冻融作用对压实黄土结构影响的微观定量研究[J].岩土工程学报,2011,33(12):1919-1925.MU Yanhu,MA Wei,LI Guoyu,et al.Quantitative analysis of impacts of freeze-thaw cycles upon microstructure of compacted loess[J].Chinese Journal of Geotechnical Engineering,2011,33(12):1919-1925.
[9]肖东辉,冯文杰,张泽,等.冻融循环对兰州黄土渗透性变化的影响[J].冰川冻土,2014,36(5):1192-1198.XIAO Donghui,FENG Wenjie,ZHANG Ze,et al.Research on the Lanzhou loess’s permeabilities changing with freezing-thawing cycles[J].Journal of Glaciology and Geocryology,2014,36(5):1192-1198.
[10]罗东海.冻融期黄土滑坡试验研究[D].西安:西安科技大学,2010.LUO Donghai.Experiment for loess landside of freezing-thawing[D].Xi’an:Xi’an University of Science and Technology,2010.
[11]吴玮江,王念秦.甘肃滑坡灾害[M].兰州:兰州大学出版社,2006.WU Weijiang,WANG Nianqin.Landslide disaster in Gansu[M].Lanzhou:Lanzhou Press,2006.
[12]王宁,毛云程,张德文,等.冻融循环对季节冻土区黄土路堑边坡的影响[J].公路交通科技(应用技术版),2011(4):79-84.WANG Ning,MAO Yuncheng,ZHAGN Dewen,et al.The influence of freeze-thaw cycles on loess cutting slope in seasonal frozen regions[J].Journal of Highway and Transportation Research and Development,2011(4):79-84.
[13]王念秦,姚勇.季节冻土区冻融期黄土滑坡基本特征与机理[J].防灾减灾工程学报,2008,28(2):163-166.WANG Nianqin,YAO Yong.Characteristics and mechanism of Landslides in loess during freezingthawing periods in seasonally frozen ground regions[J].Journal of Disaster Prevention and Mitigation Engineering,2008,28(2):163-166.
[14]陈国庆,黄润秋,石豫川,等.基于动态和整体强度折减法的边坡稳定性分析[J].岩石力学与工程学报,2014,33(2):243-256.CHEN Guoqing,HUANG Runqiu,SHI Yuchuan,et al.Stability analysis of slope based on dynamic and whole strength reduction methods[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(2):243-256.
[15]林杭,曹平,宫凤强.位移突变判据中监测点的位置和位移方式分析[J].岩土工程学报,2007,9(9):1433-1438.LIN Hang,CAO Ping,GONG Fengqiang.Analysis of locations and displacement modes of monitoring points in displacement mutation criteria[J].Chinese Journal of Geotechnical Engineering,2007,9(9):1433-1438.
[16]栾茂田,武亚军,年廷凯.强度折减有限元法中边坡失稳的塑性区判据及其应用[J].防灾减灾工程学报,2003,23(3):1-8.LUAN Maotian,WU Yajun,NIAN Tingkai.A Criterion for Evaluating Slope Stability Based on Development of Plastic Zone by Shear Strength Reduction FEM[J].Journal of Disaster Prevention and Mitigation Engineering,2003,23(3):1-8.
[17]赵尚毅,郑颖人,张玉芳.有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.ZHAO Shangyi,ZHENG Yingren,ZHANG Yufang.Study on slop failure criterion in strength reduction finite element method[J].Rock and Soil Mechanics,2005,26(2):332-336.
[18]裴利剑,屈本宁,钱闪光.有限元强度折减法边坡失稳判据的统一性[J].岩土力学,2010,31(10):3337-3341.PEI Lijian,QU Benning,QIAN Shanguang.Uniformity of slope instability criteria of strength reduction with FEM[J].Rock and Soil Mechanics,2010,31(10):3337-3341.
[2]许领,戴福初,邝国麟,等.黄土滑坡典型工程地质问题分析[J].岩土工程学报,2009,31(2):288-292.XU Ling,DAI Fuchu,KUANG Guolin,et al.Analysis of some special engineering-geological problems of loess landslide[J].Chinese Journal of Geotechnical Engineering,2009,31(2):288-292.
[3]刘悦,黄强兵.黄土路堑边坡开挖变形机理的离心模型试验研究[J].水文地质工程地质,2007,34(3):59-62.LIU Yue,HUANG Qiangbing.Centrifuge model test on the deformation mechanism of loess cut slope[J].Hydrogeology&Engineering Geology,2007,34(3):59-62.
[4]李荣建,郑文,刘军定,等.考虑初始结构性参数的结构性黄土边坡稳定性评价[J].岩土力学,2014,35(1):144-150.LI Rongjian,ZHENG Wen,LIU Junding,et al.Evaluation of stability of structural loess slope considering initial structural parameters[J].Rock and Soil Mechanics,2014,35(1):144-150.
[5]周泓,张泽,秦琦,等.冻融循环作用下黄土基本物理性质变异性研究[J].冰川冻土,2015,37(1):162-168.ZHOU Hong,ZHANG Ze,QIN Qi,et al.Research onvariability of basic physical properties of loess under freezing-thawing cycles[J].Journal of Glaciology and Geocryology,2015,37(1):162-168.
[6]叶万军,杨更社,彭建兵,等.冻融循环导致洛川黄土边坡剥落病害产生机制的试验研究[J].岩石力学与工程学报,2012,31(1):199-205.YE Wanjun,YANG Gengshe,PENG Jianbing,et al.Test research on mechanism of freezing-thawing cycle resulting in loess slope spalling hazards in luochuan[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(1):199-205.
[7]王铁行,罗少锋,刘小军.考虑含水率影响的非饱和原状黄土冻融强度试验研究[J].岩土力学,2010,31(8):2378-2382.WANG Tiehang,LUO Shaofeng,LIU Xiaojun.Testing study of freezing-thawing strength of unsaturated undisturbed loess considering influence of moisture content[J].Rock and Soil Mechanics,2010,31(8):2378-2382.
[8]穆彦虎,马巍,李国玉,等.冻融作用对压实黄土结构影响的微观定量研究[J].岩土工程学报,2011,33(12):1919-1925.MU Yanhu,MA Wei,LI Guoyu,et al.Quantitative analysis of impacts of freeze-thaw cycles upon microstructure of compacted loess[J].Chinese Journal of Geotechnical Engineering,2011,33(12):1919-1925.
[9]肖东辉,冯文杰,张泽,等.冻融循环对兰州黄土渗透性变化的影响[J].冰川冻土,2014,36(5):1192-1198.XIAO Donghui,FENG Wenjie,ZHANG Ze,et al.Research on the Lanzhou loess’s permeabilities changing with freezing-thawing cycles[J].Journal of Glaciology and Geocryology,2014,36(5):1192-1198.
[10]罗东海.冻融期黄土滑坡试验研究[D].西安:西安科技大学,2010.LUO Donghai.Experiment for loess landside of freezing-thawing[D].Xi’an:Xi’an University of Science and Technology,2010.
[11]吴玮江,王念秦.甘肃滑坡灾害[M].兰州:兰州大学出版社,2006.WU Weijiang,WANG Nianqin.Landslide disaster in Gansu[M].Lanzhou:Lanzhou Press,2006.
[12]王宁,毛云程,张德文,等.冻融循环对季节冻土区黄土路堑边坡的影响[J].公路交通科技(应用技术版),2011(4):79-84.WANG Ning,MAO Yuncheng,ZHAGN Dewen,et al.The influence of freeze-thaw cycles on loess cutting slope in seasonal frozen regions[J].Journal of Highway and Transportation Research and Development,2011(4):79-84.
[13]王念秦,姚勇.季节冻土区冻融期黄土滑坡基本特征与机理[J].防灾减灾工程学报,2008,28(2):163-166.WANG Nianqin,YAO Yong.Characteristics and mechanism of Landslides in loess during freezingthawing periods in seasonally frozen ground regions[J].Journal of Disaster Prevention and Mitigation Engineering,2008,28(2):163-166.
[14]陈国庆,黄润秋,石豫川,等.基于动态和整体强度折减法的边坡稳定性分析[J].岩石力学与工程学报,2014,33(2):243-256.CHEN Guoqing,HUANG Runqiu,SHI Yuchuan,et al.Stability analysis of slope based on dynamic and whole strength reduction methods[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(2):243-256.
[15]林杭,曹平,宫凤强.位移突变判据中监测点的位置和位移方式分析[J].岩土工程学报,2007,9(9):1433-1438.LIN Hang,CAO Ping,GONG Fengqiang.Analysis of locations and displacement modes of monitoring points in displacement mutation criteria[J].Chinese Journal of Geotechnical Engineering,2007,9(9):1433-1438.
[16]栾茂田,武亚军,年廷凯.强度折减有限元法中边坡失稳的塑性区判据及其应用[J].防灾减灾工程学报,2003,23(3):1-8.LUAN Maotian,WU Yajun,NIAN Tingkai.A Criterion for Evaluating Slope Stability Based on Development of Plastic Zone by Shear Strength Reduction FEM[J].Journal of Disaster Prevention and Mitigation Engineering,2003,23(3):1-8.
[17]赵尚毅,郑颖人,张玉芳.有限元强度折减法中边坡失稳的判据探讨[J].岩土力学,2005,26(2):332-336.ZHAO Shangyi,ZHENG Yingren,ZHANG Yufang.Study on slop failure criterion in strength reduction finite element method[J].Rock and Soil Mechanics,2005,26(2):332-336.
[18]裴利剑,屈本宁,钱闪光.有限元强度折减法边坡失稳判据的统一性[J].岩土力学,2010,31(10):3337-3341.PEI Lijian,QU Benning,QIAN Shanguang.Uniformity of slope instability criteria of strength reduction with FEM[J].Rock and Soil Mechanics,2010,31(10):3337-3341.