黄土震陷性深度特征的试验研究
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摘要
黄土震陷是地震发生时黄土地区发生的一种灾害。以典型马兰黄土(Q3)作为研究对象,对5组不同深度的原状黄土试样进行室内动三轴震陷试验,研究了该场地黄土震陷性随深度的变化特征。研究结果表明,(1)在天然含水率或是增湿、减湿情况下,黄土震陷深度曲线随动应力的增加均经历了一个从平稳、快速、再收敛至最大震陷深度的发展过程;(2)黄土震陷深度曲线的发展阶段动应力区间不尽相同,随着含水率的增加,黄土震陷快速发展期的动应力区间在变窄,最小动应力值变小,含水率20%条件下比5%最小动应力值可降低30%;(3)典型马兰黄土存在一个最大震陷深度,其最大震陷深度不受动应力、含水率影响,含水率仅能够降低达到最大震陷深度时最小动应力,加速黄土震陷深度的发展进程。在动应力不断增加的情况下,最终的黄土震陷深度曲线收敛于最大震陷深度,本次实验黄土场地的最大震陷深度约为15.5m。
Loess seismic subsidence is a type of disaster when the earthquake occurred in a loess area.The characteristics of loess seismic subsidence with depth is studied by indoor dynamic triaxial test of 5 groups of original Malan loess Q3 samples in different depths.The results show that:(1) In terms of natural water contend,humidification or dehumidification,the depth of the loess seismic subsidence,with the increase dynamic stress,has a process of from smooth to rapid lowering,and then converging to the maximum depth of seismic subsidence.(2) Dynamic stress intervals are different corresponding to stages,interval in rapid lowering stage becoming narrow;the minimum dynamic stress shrinking with increase of water content;and the minimum dynamic stress can lower by 30% in term of 20% comparing to 5%.(3) The maximum depth of loess seismic subsidence is found and it is not affected by the dynamic stress and water content.Only the water content is able to reduce minimum dynamic stress when reaching maximum depth of the seismic subsidence and speeds up the development process.At last,the loess seismic subsidence curves of the depth converging to the maximum of depth of seismic subsidence with increasing of the dynamic stress;and in this experiment the maximum depth is 15.5 m.
Loess seismic subsidence is a type of disaster when the earthquake occurred in a loess area.The characteristics of loess seismic subsidence with depth is studied by indoor dynamic triaxial test of 5 groups of original Malan loess Q3 samples in different depths.The results show that:(1) In terms of natural water contend,humidification or dehumidification,the depth of the loess seismic subsidence,with the increase dynamic stress,has a process of from smooth to rapid lowering,and then converging to the maximum depth of seismic subsidence.(2) Dynamic stress intervals are different corresponding to stages,interval in rapid lowering stage becoming narrow;the minimum dynamic stress shrinking with increase of water content;and the minimum dynamic stress can lower by 30% in term of 20% comparing to 5%.(3) The maximum depth of loess seismic subsidence is found and it is not affected by the dynamic stress and water content.Only the water content is able to reduce minimum dynamic stress when reaching maximum depth of the seismic subsidence and speeds up the development process.At last,the loess seismic subsidence curves of the depth converging to the maximum of depth of seismic subsidence with increasing of the dynamic stress;and in this experiment the maximum depth is 15.5 m.
引文
[1]王兰民,石玉成,刘旭.黄土动力学[M].北京:地震出版社,2003.
[2]张振中.黄土地震灾害预测[M].北京:地震出版社,1999.
[3]张振中,段汝文.黄土震陷研究与震害[J].西北地震学报,1987,9(增刊):63-69.ZHANG Zhen-zhong,DUAN Ru-wen.Study on seismic subsidence and seismic hazards of loess[J].Northwest Seismological Journal,1987,9(Supp.):63-69.
[4]王兰民,张振中.地震时黄土震陷量的估算方法[J].自然灾害学报,1993,2(3):85-94.WANG Lan-min,ZHANG Zhen-zhong.A method of estimating the quantity of seismic subsidence in loess deposits during earthquakes[J].Journal of Natural Disasters,1993,2(3):85-94.
[5]何光,朱鸿博.黄土震陷研究[J].岩土工程学报,1990,12(6):99-103.HE Guang,ZHU Hong-bo.Study on loess seismic subsidence[J].Chinese Journal of Geotechnical Engineering,1990,12(6):99-103.
[6]王兰民,袁中夏,石玉成,等.黄土地震灾害区划指标与方法研究[J].自然灾害学报,1999,8(3):87-92.WANG Lan-min,YUAN Zhong-xia,SHI Yu-cheng,et al.Study on the methods and indexes of zonation for seismic loessal disasters[J].Journal of Natural Disasters,1999,8(3):87-92.
[7]谢定义,齐吉琳.土结构性及其定量化参数研究的新途径[J].岩土工程学报,1999,21(6):651-656.XIE Ding-yi,QI Ji-lin.Soil structure characteristics and new approach in research on its quantitative parameter[J].Chinese Journal of Geotechnical Engineering,1999,21(6):651-656.
[8]胡再强,沈珠江,谢定义.非饱和黄土的结构性研究[J].岩石力学与工程学报,2000,19(6):775-779.HU Zai-qiang,SHEN Zhu-jiang,XIE Ding-yi.Research on structureal behavior of unsaturated loess[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(6):775-779.
[9]李永乐,张红芬,余小光,等.原状非饱和黄土的三轴试验研究[J].岩土力学,2008,29(10):2859-2863.LI Yong-le,ZHANG Hong-fen,YU Xiao-guang,et al.Experimental study of triaxial test of undisturbed unsaturated loess[J].Rock and Soil Mechanics,2008,29(10):2859-2863.
[10]李保雄,牛永红,苗天德.兰州马兰黄土的物理力学特性[J].岩土力学,2007,28(6):1077-1082.LI Bao-xiong,NIU Yong-hong,MIAO Tian-de.Physico-mechanical characteristics of Malan loess in Lanzhou region[J].Rock and Soil Mechanics,2007,28(6):1077-1082.
[11]陈存礼,何军芳,杨鹏.考虑结构性影响的原状黄土本构关系[J].岩土力学,2007,28(11):2284-2290.CHEN Cun-li,HE Jun-fang,YANG Peng.Constitutive relationship of intact loess considering structural effect[J].Rock and Soil Mechanics,2007,28(11):2284-2290.
[12]巫志辉,方彦.原状黄土在增湿时的震陷特性[C]//第三届全国土动力学学术会议论文集.上海:[出版者不祥],1990.
[13]张冬丽,王兰民,王玉华.有限元分析方法在黄土地基震陷预测中的应用[J].西北地震学报,2002,24(3):208-214.ZHANG Dong-li,WANG Lan-min,WANG Yu-hua.Application of FEM to prediction of seismic subsidence of loess ground[J].Northwestern Seismological Journal,2002,24(3):208-214.
[14]齐吉琳,赵武国,张振中.甘肃永登5.8级地震黄土震害特征及机理分析[J].西北地震学报,1998,20(1):70-75.QI Ji-lin,ZHAO Wu-guo,ZHANG Zhen-zhong.Analysis of characteristics and mechanism of the seismic damage in loess in Yongdeng Ms5.8earthquake region,Gansu province[J].Northwestern Seismological Journal,1998,20(1):70-75.
[15]陕西省计划委员会.GB50025-2004湿陷性黄土地区建筑规范[S].北京:中国建筑工业出版社,2004.
[2]张振中.黄土地震灾害预测[M].北京:地震出版社,1999.
[3]张振中,段汝文.黄土震陷研究与震害[J].西北地震学报,1987,9(增刊):63-69.ZHANG Zhen-zhong,DUAN Ru-wen.Study on seismic subsidence and seismic hazards of loess[J].Northwest Seismological Journal,1987,9(Supp.):63-69.
[4]王兰民,张振中.地震时黄土震陷量的估算方法[J].自然灾害学报,1993,2(3):85-94.WANG Lan-min,ZHANG Zhen-zhong.A method of estimating the quantity of seismic subsidence in loess deposits during earthquakes[J].Journal of Natural Disasters,1993,2(3):85-94.
[5]何光,朱鸿博.黄土震陷研究[J].岩土工程学报,1990,12(6):99-103.HE Guang,ZHU Hong-bo.Study on loess seismic subsidence[J].Chinese Journal of Geotechnical Engineering,1990,12(6):99-103.
[6]王兰民,袁中夏,石玉成,等.黄土地震灾害区划指标与方法研究[J].自然灾害学报,1999,8(3):87-92.WANG Lan-min,YUAN Zhong-xia,SHI Yu-cheng,et al.Study on the methods and indexes of zonation for seismic loessal disasters[J].Journal of Natural Disasters,1999,8(3):87-92.
[7]谢定义,齐吉琳.土结构性及其定量化参数研究的新途径[J].岩土工程学报,1999,21(6):651-656.XIE Ding-yi,QI Ji-lin.Soil structure characteristics and new approach in research on its quantitative parameter[J].Chinese Journal of Geotechnical Engineering,1999,21(6):651-656.
[8]胡再强,沈珠江,谢定义.非饱和黄土的结构性研究[J].岩石力学与工程学报,2000,19(6):775-779.HU Zai-qiang,SHEN Zhu-jiang,XIE Ding-yi.Research on structureal behavior of unsaturated loess[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(6):775-779.
[9]李永乐,张红芬,余小光,等.原状非饱和黄土的三轴试验研究[J].岩土力学,2008,29(10):2859-2863.LI Yong-le,ZHANG Hong-fen,YU Xiao-guang,et al.Experimental study of triaxial test of undisturbed unsaturated loess[J].Rock and Soil Mechanics,2008,29(10):2859-2863.
[10]李保雄,牛永红,苗天德.兰州马兰黄土的物理力学特性[J].岩土力学,2007,28(6):1077-1082.LI Bao-xiong,NIU Yong-hong,MIAO Tian-de.Physico-mechanical characteristics of Malan loess in Lanzhou region[J].Rock and Soil Mechanics,2007,28(6):1077-1082.
[11]陈存礼,何军芳,杨鹏.考虑结构性影响的原状黄土本构关系[J].岩土力学,2007,28(11):2284-2290.CHEN Cun-li,HE Jun-fang,YANG Peng.Constitutive relationship of intact loess considering structural effect[J].Rock and Soil Mechanics,2007,28(11):2284-2290.
[12]巫志辉,方彦.原状黄土在增湿时的震陷特性[C]//第三届全国土动力学学术会议论文集.上海:[出版者不祥],1990.
[13]张冬丽,王兰民,王玉华.有限元分析方法在黄土地基震陷预测中的应用[J].西北地震学报,2002,24(3):208-214.ZHANG Dong-li,WANG Lan-min,WANG Yu-hua.Application of FEM to prediction of seismic subsidence of loess ground[J].Northwestern Seismological Journal,2002,24(3):208-214.
[14]齐吉琳,赵武国,张振中.甘肃永登5.8级地震黄土震害特征及机理分析[J].西北地震学报,1998,20(1):70-75.QI Ji-lin,ZHAO Wu-guo,ZHANG Zhen-zhong.Analysis of characteristics and mechanism of the seismic damage in loess in Yongdeng Ms5.8earthquake region,Gansu province[J].Northwestern Seismological Journal,1998,20(1):70-75.
[15]陕西省计划委员会.GB50025-2004湿陷性黄土地区建筑规范[S].北京:中国建筑工业出版社,2004.
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