浅埋水平锚板极限承载特性试验研究

Experimental Study on the Limit Bearing Characteristics of Shallow Horizontal Anchor Plate

摘要: 为研究浅埋水平锚定板极限承载特性，本文采用钢棒相似土替代传统砂土，结合GeoPIV (particle image velocimetry)粒子图像测速法，通过开展极限拉拔试验，研究平面应变条件下下锚板抗拔力及位移响应特征，得出不同埋深比下锚板周围填料位移场分布及应变特性，揭示浅埋水平锚板承载机理。研究结果表明：锚板荷载与竖向位移响应大致可分为三个阶段：包括峰前弹性阶段、峰后下降阶段以及波动阶段，极限上拔力随埋深率的增加成几何级数增加；在张拉过程中，锚板两侧出现对称斜向破裂面并随着锚板竖向位移的增加逐渐发展至表面，破裂面与竖直方向的夹角大致等于45˚-φ/2；板顶高度1D (D为锚定板宽度)范围内形成刚性三角形，且在拉拔过程中刚性三角形的大小保持不变。试验结果可为水平锚板极限平衡计算模型建立提供参考。

Abstract: In order to study the ultimate bearing characteristics of shallow buried horizontal anchoring plates, this paper uses steel bar similar soil instead of traditional sand, combined with GeoPIV (particle image velocimetry), through the ultimate drawing test, to study the lower anchor plate under plane strain conditions. The pullout force and displacement response characteristics are obtained. The displacement field distribution and strain characteristics of the surrounding material around the anchor plate are obtained, and the bearing mechanism of the shallow buried horizontal anchor plate is revealed. The results show that the anchor plate load and vertical displacement response can be roughly divided into three stages: including the pre-peak elastic stage, the post-peak descending stage and the wave stage. The ultimate pull-out force increases with the increase of the buried depth rate into a geometric series. During the tensioning process, symmetric oblique fracture surfaces appear on both sides of the anchor plate and gradually develop to the surface with the increase of the vertical displacement of the anchor plate. The angle between the fracture surface and the vertical direction is approximately equal to 45˚-φ/2. A rigid triangle is formed in the range of the top height 1D (D is the anchoring plate width), and the size of the rigid triangle remains unchanged during the drawing process. The test results can provide reference for the establishment of the horizontal anchor plate limit equilibrium calculation model.