不同轴压下悬挂式防渗墙堤基渗透坡降试验

为了研究含悬挂式防渗墙的强透水堤坝坝基在不同轴压状态下的渗透特性,分别开展了3种不同高度防渗墙在不同轴向应力状态下的渗流-应力耦合管涌试验。结果表明:防渗墙端部位置渗透流速较大,更易发生渗透破坏;坝基平均渗透坡降随防渗墙高度增加而减小,防渗墙渗流轮廓线上,防渗墙端部的渗流梯度最大,应力状态对悬挂式防渗墙-砂砾石地基渗透坡降影响显著,管涌临界渗透坡降与轴压呈抛物线关系,防渗墙端部的渗透破坏坡降随轴压增大而线性增大。在此基础上,建立了用轴压表示的防渗墙端部渗透破坏坡降线性经验公式。

Experimental study on seepage gradient of embankment foundations with suspended cut-off walls under different axial pressures

In order to study the permeability of highly permeable embankment foundations with suspended cut-off walls, a series of seepage-stress coupling experiments with cut-off walls of three different heights in different axial stress states were carried out. Results show that seepage failure is more likely to occur at the bottom of cut-off walls because of high seepage velocity there, the average seepage gradient of the embankment foundation decreases with the increase of the height of cut-off walls, and the seepage gradient at the bottom of cut-off walls is always maximum along the seepage contour line. Stress states have large effects on the seepage gradient of sand gravel foundations with suspended cut-off walls. There is a parabolic relationship between critical seepage gradient of piping and axial pressure. The seepage gradient causing seepage failure at the bottom of cut-off walls increases linearly with the increase in axial pressure. Based on these results, a linear empirical formula for the seepage gradient causing seepage failure at the bottom of cut-off walls, denoted by the axial pressure, is established.