不同地区饱和原状黄土静态液化特性试验研究
|
摘要
黄土因饱水静态液化而发生突发性失稳破坏,易造成人员伤亡和财产损失。按照颗粒级配的不同,中国黄土分为砂质、粉质和黏质黄土,不同区域的黄土具有不同的静态液化特性。利用GDS三轴试验系统,对陕西神木砂质黄土区(Q_3黄土)、甘肃黑方台粉质黄土区(Q_3黄土)和陕西泾阳黏质黄土区(Q_2黄土)原状饱和黄土进行了等向固结不排水三轴剪切(ICU)试验,研究了初始孔隙比和颗粒级配对原状黄土静态液化能力的影响。试验结果表明:①3个地区的饱和原状土的应力-应变关系均为软化型,在中低围压下泾阳饱和原状黄土不发生液化,仅表现出弱软化现象;②中低围压下,初始孔隙比是影响原状黄土静态液化的主要因素,高围压下,初始孔隙比的影响逐渐减小,颗粒级配成为影响原状黄土静态液化的主要因素。
The frequent occurrence of sudden loess landslides triggered by static liquefaction threatens the local development.On the basis of grain size distribution,the Chinese loess is commonly classified into sandy loess,silty loess,and clayey loess.We find that the Chinese loess located in different regions has different susceptibility to static liquefaction.Based on the isotropically undrained shearing test(ICU),the intact saturated sandy loess,silty loess,and the clayey loess were investigated to better understand the effects of initial void ratio and grain size distribution on the static liquefaction susceptibility.The results show that loess from three regions are strain-softening in the stress-strain relations,and under the middle and low confining pressure Jingyang saturated undisturbed sample only showed weak softening phenomenon.Under low to middle confining pressure,the initial void ratio is the main factor that affects the static liquefaction of undisturbed loess,and under the high confining pressure,the effect of initial void ratio gradually decreases and the grain size distribution becomes the main factor that influences the susceptibility of static liquefaction of intact loess.
The frequent occurrence of sudden loess landslides triggered by static liquefaction threatens the local development.On the basis of grain size distribution,the Chinese loess is commonly classified into sandy loess,silty loess,and clayey loess.We find that the Chinese loess located in different regions has different susceptibility to static liquefaction.Based on the isotropically undrained shearing test(ICU),the intact saturated sandy loess,silty loess,and the clayey loess were investigated to better understand the effects of initial void ratio and grain size distribution on the static liquefaction susceptibility.The results show that loess from three regions are strain-softening in the stress-strain relations,and under the middle and low confining pressure Jingyang saturated undisturbed sample only showed weak softening phenomenon.Under low to middle confining pressure,the initial void ratio is the main factor that affects the static liquefaction of undisturbed loess,and under the high confining pressure,the effect of initial void ratio gradually decreases and the grain size distribution becomes the main factor that influences the susceptibility of static liquefaction of intact loess.
引文
[1]Xu L,Coop M R.Influence of structure on the behavior of a saturated clayey loess[J].Canadian Geotechnical Journal,2016,53(6):1026-1037.
[2]Xu L,Coop M R,Zhang M S,et al.The mechanics of a saturated silty loess and implications for landslides[J].Engineering Geology,2017,236:29-42.
[3]刘东生.黄土与环境[M].北京:科学出版社,1985.
[4]王峻,王兰民,王平,等.不同地区饱和黄土液化特性研究[J].水文地质工程地质,2011,38(5):54-57.
[5]何开明,周健,王兰民.黄土液化的研究现状与设想[J].地质科技情报,2004,23(1):85-88.
[6]许强,彭大雷,亓星,等.2015年4.29甘肃黑方台党川2#滑坡基本特征与成因机理研究[J].工程地质学报,2016,24(2):167-180.
[7]许领,戴福初,闵弘,等.泾阳南塬黄土滑坡类型与发育特征[J].地球科学:中国地质大学学报,2010,35(1):155-160
[8]Terzaghi K,Peck R B,Mesri G.Soil mechanics in engineering practice[M].[S.l.]:John Wiley&Sons Inc,1996.
[9]Poulos S J,Castro G,France J W.Liquefaction evaluation procedure[J].Journal of Geotechnical Engineering,1985,111(6):772-792.
[10]Kramer S L,Seed H B.Initiation of soil liquefaction under static loading conditions[J].Journal of Geotechnical Engineering,1988,114(4):412-430.
[11]Yamamuro J A,Lade P V.Static liquefaction of very loose sands[J].Canadian Geotechnical Journal,1999,34(6):905-917.
[12]金艳丽,戴福初.饱和黄土的静态液化特性试验研究[J].岩土力学,2008,29(12):3293-3298.
[13]朱登武,王文生,刘路路,等.饱和原状黄土三轴试验研究[J].河南城建学院学报,2016,25(4):45-48.
[14]巨袁臻,许强,彭大雷,等.黑方台焦家4号黄土滑坡发育特征及滑动机理[J].人民长江,2017,48(11):62-67.
[15]Take W R,Beddoe R A.Base liquefaction:A mechanism for shear-induced failure of loose granular slopes[J].Canadian Geotechnical Journal,2014,51(5):496-507.
[16]Castro G,Poulos S J.Factors affecting liquefaction and cyclic mobility[J].Journal of the Geotechnical Engineering Division,1977,103:501-516.
[2]Xu L,Coop M R,Zhang M S,et al.The mechanics of a saturated silty loess and implications for landslides[J].Engineering Geology,2017,236:29-42.
[3]刘东生.黄土与环境[M].北京:科学出版社,1985.
[4]王峻,王兰民,王平,等.不同地区饱和黄土液化特性研究[J].水文地质工程地质,2011,38(5):54-57.
[5]何开明,周健,王兰民.黄土液化的研究现状与设想[J].地质科技情报,2004,23(1):85-88.
[6]许强,彭大雷,亓星,等.2015年4.29甘肃黑方台党川2#滑坡基本特征与成因机理研究[J].工程地质学报,2016,24(2):167-180.
[7]许领,戴福初,闵弘,等.泾阳南塬黄土滑坡类型与发育特征[J].地球科学:中国地质大学学报,2010,35(1):155-160
[8]Terzaghi K,Peck R B,Mesri G.Soil mechanics in engineering practice[M].[S.l.]:John Wiley&Sons Inc,1996.
[9]Poulos S J,Castro G,France J W.Liquefaction evaluation procedure[J].Journal of Geotechnical Engineering,1985,111(6):772-792.
[10]Kramer S L,Seed H B.Initiation of soil liquefaction under static loading conditions[J].Journal of Geotechnical Engineering,1988,114(4):412-430.
[11]Yamamuro J A,Lade P V.Static liquefaction of very loose sands[J].Canadian Geotechnical Journal,1999,34(6):905-917.
[12]金艳丽,戴福初.饱和黄土的静态液化特性试验研究[J].岩土力学,2008,29(12):3293-3298.
[13]朱登武,王文生,刘路路,等.饱和原状黄土三轴试验研究[J].河南城建学院学报,2016,25(4):45-48.
[14]巨袁臻,许强,彭大雷,等.黑方台焦家4号黄土滑坡发育特征及滑动机理[J].人民长江,2017,48(11):62-67.
[15]Take W R,Beddoe R A.Base liquefaction:A mechanism for shear-induced failure of loose granular slopes[J].Canadian Geotechnical Journal,2014,51(5):496-507.
[16]Castro G,Poulos S J.Factors affecting liquefaction and cyclic mobility[J].Journal of the Geotechnical Engineering Division,1977,103:501-516.