降雨在裂隙型冰水堆积体中的入渗过程
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摘要
[目的]探究降雨在裂隙型堆积体中的入渗过程,研究降雨条件下土坡内体积含水率、基质吸力、孔压等的变化情况及湿润锋迁移规律,为降雨诱发覆盖层斜坡失稳机理提供理论支持。[方法]针对两类不同结构堆积体土样进行室内模型试验。[结果]均质模型中湿润峰均匀下渗,锋面达测点后引发孔压及体积含水率减小和基质吸力增加;坡顶受降雨影响变化明显,而坡底变化具有累积效应;裂隙构成雨水入渗的优势通道,其底部会形成暂态饱和区,湿润锋面在该区域产生强烈下凹形成渗透"漏斗",促使湿润锋在该区域先期触底;[结论]降雨入渗过程为:(1)均质型:完全入渗→入渗放缓→稳定入渗→饱和入渗;(2)裂隙发育型:完全入渗→局部强烈下渗→补偿加速下渗→水平侧渗。
[Objective]In order to investigate the rainfall infiltration process in fractured deposits,this study focuses on the variation of volume moisture content,matric suction,pore pressure and other changes in soil slope under rainfall conditions,as well as the migration low of wetting,which will provide theoretical support for the instability mechanism of rain-induced overburden slope.[Methods]The indoor model tests of two types of different structural soil deposits were carried out.[Results]The wetting fronts in the homogeneous accumulations were uniformly moving downward,the pore pressure and water content decreased and the matric suction increased when the wetting fronts reach the measuring points.The change of top slope were affected obviously by rainfall while the bottom showed a cumulative effect.The fissures constituted the dominant channel for rainwater infiltration and there was a transient saturated zone at the bottom of the fissures.The wetting fronts produced a strong depressions in this area that form a percolation"funnel"that causes the wetting fronts to reach its bottom in advance.[Conclusion]The rainfall infiltration processes are in the sequence of complete infiltration→slow infiltration→stable infiltration→saturated infiltration for homogeneous model and in the sequence of complete infiltration→local strongly infiltration→compensation accelerated infiltration→horizontal lateral infiltration for fracture model.
[Objective]In order to investigate the rainfall infiltration process in fractured deposits,this study focuses on the variation of volume moisture content,matric suction,pore pressure and other changes in soil slope under rainfall conditions,as well as the migration low of wetting,which will provide theoretical support for the instability mechanism of rain-induced overburden slope.[Methods]The indoor model tests of two types of different structural soil deposits were carried out.[Results]The wetting fronts in the homogeneous accumulations were uniformly moving downward,the pore pressure and water content decreased and the matric suction increased when the wetting fronts reach the measuring points.The change of top slope were affected obviously by rainfall while the bottom showed a cumulative effect.The fissures constituted the dominant channel for rainwater infiltration and there was a transient saturated zone at the bottom of the fissures.The wetting fronts produced a strong depressions in this area that form a percolation"funnel"that causes the wetting fronts to reach its bottom in advance.[Conclusion]The rainfall infiltration processes are in the sequence of complete infiltration→slow infiltration→stable infiltration→saturated infiltration for homogeneous model and in the sequence of complete infiltration→local strongly infiltration→compensation accelerated infiltration→horizontal lateral infiltration for fracture model.
引文
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[11]辛明明,杜友福.膨胀土裂隙生成特征研究.[J].建材世界,2016,32(6):17-20.
[2]周中,傅鹤林,刘宝琛,等.土石混合体边坡人工降雨木你试验研究[J].岩土力学,2007,28(7):1931-1936.
[3]王一兆,隋耀华.降雨入渗对边坡浅层稳定性的影响[J].长江科学院院报,2017,34(4):122-125.
[4]郁舒阳,张继勋,任旭华,等.降雨类型对浅层深层滑坡渗流及稳定性的影响[J].水电能源科学,2018,36(3):123-127.
[5]林鸿州,于玉贞,李广信,等.降雨特性对土质边坡失稳的影响[J].岩石力学与工程学报,2009,28(1):198-204.
[6]杜婷婷,李志清,王晓明,等.黄土边坡降雨冲刷模型试验研究[J].工程地质学报,2018,26(3):733-740.
[7]刘博,孙树林,刘俊,等.降雨入渗条件下裂隙发育的黄土边坡稳定性分析研究[J].工程勘察,2006(10):16-21.
[8]姚海林,郑少河,葛修润,等.裂隙膨胀土边坡稳定性评价[J].岩石力学与工程学报,2002,21(S2):2331-2335.
[9]张维,张国宝,魏星,等.裂隙位置及深度对膨胀土边坡稳定性影响分析.[J].路基工程,2018(3):20-25.
[10]陈善雄,戴张俊,陆定杰,等.考虑裂隙分布及强度的膨胀土边坡稳定性分析[J].路基工程,2014,12(45):1442-1449.
[11]辛明明,杜友福.膨胀土裂隙生成特征研究.[J].建材世界,2016,32(6):17-20.