考虑应力状态的悬挂式防渗墙-砂砾石地基管涌临界坡降试验研究

悬挂式防渗墙-强透水地基所处的应力状态，对其管涌等渗透变形发展过程影响明显。利用自行研制的新型土与结构物接触剪切渗透仪，开展不同应力状态下悬挂式防渗墙--缺乏中间级配的管涌型砂砾石地基的渗流-应力耦合管涌试验研究。结果表明，应力状态对悬挂式防渗墙-砂砾石地基的管涌临界渗透坡降影响巨大，围压越大，管涌临界渗透坡降越大，基于试验结果，建立了由围压表示的管涌临界渗透坡降线性经验公式。研究成果体现了渗流-应力耦合效应对防渗墙-砂砾石地基渗透稳定性的影响，可为确定深厚覆盖层中悬挂式防渗墙的合理贯入深度提供重要的理论依据。

Study of critical piping hydraulic gradient of suspended cut-off wall and sand gravel foundation under different stress states

The stress states of suspended cut-off wall and strong permeable foundation plays an important role in the evolution of piping.A series of seepage-stress coupling experiments on the suspended cut-off wall and piping-typed sand gravel foundation under different stress states are carried out using a newly designed soil-structure contact shear permeameter.The results show that the stress state has a great influence on the critical piping hydraulic gradient of the suspended cut-off wall and sand gravel foundation;the larger the confining pressure is,the larger the critical piping hydraulic gradient is.A linear empirical formula on the critical piping hydraulic gradient denoted by the confining pressure is established based on the experiment results.The results show the intensive influence of the seepage-stress coupling effect on the seepage stability of the cut-off wall and sand gravel foundation,so as to provide an important theoretical basis for determining the reasonable penetration depth of the suspended cut-off wall in deep overburden foundation.