黄土-泥岩接触面滑坡滑带土力学特征研究
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摘要
滑带土是滑坡形成过程中形成的一层结构性较差的土体,是滑坡的重要组成部分。其物理力学性质、微观结构与滑坡的形成以及后期运动特征密切相关。黄土-泥岩接触面滑坡是按照滑坡地质成因划分的一种上层黄土、下层泥岩的具有"双层异质"结构的滑坡。此类滑坡由于在滑动中具有缓动低速的特点,往往早期不易被发现,发现时已造成了严重的危害。采用GDS三轴仪对天水地区花南村滑坡、半山村滑坡和咀头村滑坡三个黄土-泥岩接触面滑坡的滑带土力学性质进行研究,结合滑带土微观结构特征,分析黄土-泥岩接触面滑坡滑带土的力学变化特征及其变形内在机理。研究发现:滑带土中大量存在被黏土颗粒包裹的大颗粒,这些大颗粒在滑带土变形过程中经历错位、滑移等过程后,大颗粒进一步滑移受到黏土质限制,导致黄土-泥岩接触面滑坡滑带土在宏观上表现出应变硬化的典型特征。此外,剪切中孔隙水压力无法及时消散也是此类滑坡变形的重要特征之一。应变硬化造成滑带土在滑动中强度未出现残余值而导致滑坡处于持续运动中,能量的释放方式属于缓慢释放型。因此该类滑坡滑动具有缓动低速的特性。
Slip zone soil,an important part of landslide,is a layer of soil which has weak structure,of which the physical and mechanical properties and the microstructure are closely related to the development of landslide and the followed motion features.The loess-mudstone interface landslide is classified according to the geological origin,of which the upper part is loess while the underlying one is mudstone.This kind of landslide is difficult to be noticed in early stage due to the features of gentle movement with low velocity.So when it caught the attention,it had resulted in serious harm.In this thesis,the GDS triaxial apparatus was used to research the mechanical properties of the slip zone soils which were sampled from Huanancun landslide,Banshancun landslide and Zuitoucun Landslide.The change characteristics of the mechanical properties were analyzed in combination with microstructure features.The research results show that there are larger particles wrapped by clay in the slip zone.These larger particles suffer dislocation and slippage during the deformation of slip zone soil.Meanwhile,they would be restricted by the ambient clay.As a result,in the slip zone soil shows typical macroscopic characteristics of strain hardening.Besides,another important feature of this kind landslide is that the pore water pressure cannot dissipate timely.Strain hardening makes the slip zone soil remain in continuous movement without significant residual strength,and the energy is releasing gradually.These reasons makes this kind of landslide moves gently with low velocity.
Slip zone soil,an important part of landslide,is a layer of soil which has weak structure,of which the physical and mechanical properties and the microstructure are closely related to the development of landslide and the followed motion features.The loess-mudstone interface landslide is classified according to the geological origin,of which the upper part is loess while the underlying one is mudstone.This kind of landslide is difficult to be noticed in early stage due to the features of gentle movement with low velocity.So when it caught the attention,it had resulted in serious harm.In this thesis,the GDS triaxial apparatus was used to research the mechanical properties of the slip zone soils which were sampled from Huanancun landslide,Banshancun landslide and Zuitoucun Landslide.The change characteristics of the mechanical properties were analyzed in combination with microstructure features.The research results show that there are larger particles wrapped by clay in the slip zone.These larger particles suffer dislocation and slippage during the deformation of slip zone soil.Meanwhile,they would be restricted by the ambient clay.As a result,in the slip zone soil shows typical macroscopic characteristics of strain hardening.Besides,another important feature of this kind landslide is that the pore water pressure cannot dissipate timely.Strain hardening makes the slip zone soil remain in continuous movement without significant residual strength,and the energy is releasing gradually.These reasons makes this kind of landslide moves gently with low velocity.
引文
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[6]Carey J M,Petley D N.Progressive shear-surface development in cohesive materials implications for landslide behaviour[J].Engineering Geology,2014,177(14):54-65.
[7]Bishop A W,Green G E,Garga V K,et al.A new ring shear apparatus and its application to the measurement of residual strength[J].Géotechnique,1971,21(4):273-328.
[8]Townsend F C,Gilbert P A.Tests to measure residual strength of some clay shales[J].Géotechnique,1973,23(2):267-271.
[9]Anson R W W,Hawkins A B.Analysis of a sample containing a shear surface from a recent landslip,south Cotswolds[J].Géotechnique,1999,49(1):33-41.
[10]Skempton A W.Residual strength of clays in landslides folded strata and the laboratory[J].Gétechnique,1985,35(1):3-18.
[11]Vithana S B,Nakamura S,Kimura S,et al.Effects of overconsolidation ratios on the shear strength of remolded slip surface soils in ring shear[J].Engineering Geology,2012,131-132(13):29-36.
[12]Skempton A W.First-time slides in over-consolidated clays[J].Géotechnique,1970,20(3):320-324.
[13]Zhang Luming,Zheng Mingxin,He Min.Study of characteristics of matric suction in landslide slip soils before and after landslide control[J].Rock and Soil Mechanics,2010,31(10):3305-3312.[张卢明,郑明新,何敏.滑坡防治前后滑带土基质吸力特征研究[J].岩土力学,2010,31(10):3305-3312.]
[14]Long Jianhui,Li Tonglu,Lei Xiaofeng,et al.Study on physical properties of soil in sliding zone of loess landslip[J].Chinese Journal of Geotechnical Engineering,2007,29(2):289-293.[龙建辉,李同录,雷晓锋,等.黄土滑坡滑带土的物理特性研究[J].岩土工程学报,2007,29(2):289-293.]
[15]Chen Wenwu,Liu Wei,Lin Gaochao,et al.The study on sensitivity of landslide induced by changes in loess structure[J].Journal of Glaciology and Geocryology,2016,38(4):929-936.[谌文武,刘伟,林高潮,等.天水黄土结构性变化诱发滑坡敏感性分析[J].冰川冻土,2016,38(4):929-936.]
[16]Wu Weijiang,Ye Weiling,Yao Zhengxue,et al.Characteristics of the Luojiapo loess landslides at Heifangtai,burst on April 29,2015,in Yongjing County,Gansu Province[J].Journal of Glaciology and Geocryology,2016,38(3):662-670.[吴玮江,叶伟林,姚正学,等.甘肃永靖黑方台4·29罗家坡黄土滑坡的特征[J].冰川冻土,2016,38(3):662-670.]
[17]Gibo S,Egashira K,Ohtsubo M.Residual strength of smectitedominated soils from the Kamenose landslide in Japan[J].Canadian Geotechnical Journal,2011,24(3):456-461.
[18]Liu Dong,Chen Xiaoping.Microscopic observation and analysis of ring shear surface of slip zone soil[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(9):1827-1834.[刘动,陈晓平.滑带土环剪剪切面的微观观测与分析[J].岩石力学与工程学报,2013,32(9):1827-1834.]
[19]Hicher P Y,Wahyudi H,Tessied D.Microstructure analysis of strain localization in clay[J].Computers and Geotechnics,1994,16(3):205-222.
[20]Jiang Mingjing,Peng Licai,Zhu Hehua,et al.Microscopic investigation on shear band of marine clay in Zhuhai,China[J].Rock and Soil Mechanics,2010,31(7):2017-2023.[蒋明镜,彭立才,朱合华,等.珠海海积软土剪切带微观结构试验研究[J].岩土力学,2010,31(7):2017-2023.]
[21]Chen Song,Xu Guangli,Chen Guojin,et al.Research on engineering geology characteristics of soil in sliding zone of Huangtupo landslide in Three Gorges Reservoir area[J].Rock and Soil Mechanics,2009,30(10):3048-3052.[陈松,徐光黎,陈国金,等.三峡库区黄土坡滑坡滑带工程地质特征研究[J].岩土力学,2009,30(10):3048-3052.]
[22]Wang Hongxing,Tang Huiming,Chen Cong.Study on X-ray diffraction for the orientability of clay minerals in sliding-soil[J].Hydrogeology and Engineering Geology,2004(Suppl.1):79-81.[王洪兴,唐辉明,陈聪.滑带土黏土矿物定向性的X射线衍射及其对滑坡的作用[J].水文地质工程地质,2004(增刊1):79-81.]
[23]Song Binghui,Chen Wenwu,Wu Weijiang,et al.Microstructure fractal of sliding zone soil of Suoertou landslide in Zhouqu[J].Chinese Journal of Geotechnical Engineering,2011,33(Suppl.1):292-296.[宋丙辉,谌文武,吴玮江,等.舟曲锁儿头滑坡滑带土微结构的分形研究[J].岩土工程学报,2011,33(增刊1):292-296.]
[24]Li Jiang,Xu Qiang,Hu Zeming,et al.Experiment research on softening of undisturbed saturated slip soil in eastern of Sichuan Province red bed[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Suppl.2):4333-4342.[李江,许强,胡泽铭,等.川东红层原状滑带土饱水软化试验研究[J].岩石力学与工程学报,2015,34(增刊2):4333-4342.]
[25]Chen Jian,Dai Fuchu,Xu Ling,et al.Properties and microstructure of a natural slip zone in loose deposits of red beds,southwestern China[J].Engineering Geology,2014,183:53-64.
[26]Wu Weijiang,Wang Nianqin.Basic types and active features of loess landslide[J].The Chinese Journal of Geological Hazard and Control,2002,13(2):36-40.[吴玮江,王念秦.黄土滑坡的基本类型与活动特征[J].中国地质灾害与防治学报,2002,13(2):36-40.]
[2]Jiang Xiuzi,Wen Baoping.Creep behavior of slip zone of reactivated slow-moving landslide and its characteristic strength[J].Rock and Soil Mechanics,2015,36(2):495-501.[蒋秀姿,文宝萍.缓慢复活型滑坡滑带土的蠕变性质与特征强度试验研究[J].岩土力学,2015,36(2):495-501.]
[3]Huang Bin,Fu Xudong,Tan Fan,et al.Experimental study of relationship between water content and strength or deformation of slip soil[J].Rock and Soil Mechanics,2012,33(9):2613-2618.[黄斌,傅旭东,谭凡,等.含水率对滑带土强度及变形影响试验研究[J].岩土力学,2012,33(9):2613-2618.]
[4]Tian Bin,Dai Huichao,Wang Shimei.Strength characteristics of soil in slide zone and determination of its parameters[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(17):2887-2892.[田斌,戴会超,王世梅.滑带土结构强度特征及其强度参数取值研究[J].岩石力学与工程学报,2004,23(17):2887-2892.]
[5]Chen Xiaoping,Huang Jingwu,Yin Saihua,et al.Experimental study of strength property of slip zone soils[J].Rock and Soil Mechanics,2011,32(11):3212-3218.[陈晓平,黄井武,尹赛华,等.滑带土强度特性的试验研究[J].岩土力学,2011,32(11):3212-3218.]
[6]Carey J M,Petley D N.Progressive shear-surface development in cohesive materials implications for landslide behaviour[J].Engineering Geology,2014,177(14):54-65.
[7]Bishop A W,Green G E,Garga V K,et al.A new ring shear apparatus and its application to the measurement of residual strength[J].Géotechnique,1971,21(4):273-328.
[8]Townsend F C,Gilbert P A.Tests to measure residual strength of some clay shales[J].Géotechnique,1973,23(2):267-271.
[9]Anson R W W,Hawkins A B.Analysis of a sample containing a shear surface from a recent landslip,south Cotswolds[J].Géotechnique,1999,49(1):33-41.
[10]Skempton A W.Residual strength of clays in landslides folded strata and the laboratory[J].Gétechnique,1985,35(1):3-18.
[11]Vithana S B,Nakamura S,Kimura S,et al.Effects of overconsolidation ratios on the shear strength of remolded slip surface soils in ring shear[J].Engineering Geology,2012,131-132(13):29-36.
[12]Skempton A W.First-time slides in over-consolidated clays[J].Géotechnique,1970,20(3):320-324.
[13]Zhang Luming,Zheng Mingxin,He Min.Study of characteristics of matric suction in landslide slip soils before and after landslide control[J].Rock and Soil Mechanics,2010,31(10):3305-3312.[张卢明,郑明新,何敏.滑坡防治前后滑带土基质吸力特征研究[J].岩土力学,2010,31(10):3305-3312.]
[14]Long Jianhui,Li Tonglu,Lei Xiaofeng,et al.Study on physical properties of soil in sliding zone of loess landslip[J].Chinese Journal of Geotechnical Engineering,2007,29(2):289-293.[龙建辉,李同录,雷晓锋,等.黄土滑坡滑带土的物理特性研究[J].岩土工程学报,2007,29(2):289-293.]
[15]Chen Wenwu,Liu Wei,Lin Gaochao,et al.The study on sensitivity of landslide induced by changes in loess structure[J].Journal of Glaciology and Geocryology,2016,38(4):929-936.[谌文武,刘伟,林高潮,等.天水黄土结构性变化诱发滑坡敏感性分析[J].冰川冻土,2016,38(4):929-936.]
[16]Wu Weijiang,Ye Weiling,Yao Zhengxue,et al.Characteristics of the Luojiapo loess landslides at Heifangtai,burst on April 29,2015,in Yongjing County,Gansu Province[J].Journal of Glaciology and Geocryology,2016,38(3):662-670.[吴玮江,叶伟林,姚正学,等.甘肃永靖黑方台4·29罗家坡黄土滑坡的特征[J].冰川冻土,2016,38(3):662-670.]
[17]Gibo S,Egashira K,Ohtsubo M.Residual strength of smectitedominated soils from the Kamenose landslide in Japan[J].Canadian Geotechnical Journal,2011,24(3):456-461.
[18]Liu Dong,Chen Xiaoping.Microscopic observation and analysis of ring shear surface of slip zone soil[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(9):1827-1834.[刘动,陈晓平.滑带土环剪剪切面的微观观测与分析[J].岩石力学与工程学报,2013,32(9):1827-1834.]
[19]Hicher P Y,Wahyudi H,Tessied D.Microstructure analysis of strain localization in clay[J].Computers and Geotechnics,1994,16(3):205-222.
[20]Jiang Mingjing,Peng Licai,Zhu Hehua,et al.Microscopic investigation on shear band of marine clay in Zhuhai,China[J].Rock and Soil Mechanics,2010,31(7):2017-2023.[蒋明镜,彭立才,朱合华,等.珠海海积软土剪切带微观结构试验研究[J].岩土力学,2010,31(7):2017-2023.]
[21]Chen Song,Xu Guangli,Chen Guojin,et al.Research on engineering geology characteristics of soil in sliding zone of Huangtupo landslide in Three Gorges Reservoir area[J].Rock and Soil Mechanics,2009,30(10):3048-3052.[陈松,徐光黎,陈国金,等.三峡库区黄土坡滑坡滑带工程地质特征研究[J].岩土力学,2009,30(10):3048-3052.]
[22]Wang Hongxing,Tang Huiming,Chen Cong.Study on X-ray diffraction for the orientability of clay minerals in sliding-soil[J].Hydrogeology and Engineering Geology,2004(Suppl.1):79-81.[王洪兴,唐辉明,陈聪.滑带土黏土矿物定向性的X射线衍射及其对滑坡的作用[J].水文地质工程地质,2004(增刊1):79-81.]
[23]Song Binghui,Chen Wenwu,Wu Weijiang,et al.Microstructure fractal of sliding zone soil of Suoertou landslide in Zhouqu[J].Chinese Journal of Geotechnical Engineering,2011,33(Suppl.1):292-296.[宋丙辉,谌文武,吴玮江,等.舟曲锁儿头滑坡滑带土微结构的分形研究[J].岩土工程学报,2011,33(增刊1):292-296.]
[24]Li Jiang,Xu Qiang,Hu Zeming,et al.Experiment research on softening of undisturbed saturated slip soil in eastern of Sichuan Province red bed[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Suppl.2):4333-4342.[李江,许强,胡泽铭,等.川东红层原状滑带土饱水软化试验研究[J].岩石力学与工程学报,2015,34(增刊2):4333-4342.]
[25]Chen Jian,Dai Fuchu,Xu Ling,et al.Properties and microstructure of a natural slip zone in loose deposits of red beds,southwestern China[J].Engineering Geology,2014,183:53-64.
[26]Wu Weijiang,Wang Nianqin.Basic types and active features of loess landslide[J].The Chinese Journal of Geological Hazard and Control,2002,13(2):36-40.[吴玮江,王念秦.黄土滑坡的基本类型与活动特征[J].中国地质灾害与防治学报,2002,13(2):36-40.]