Pullout Capacity of Block Anchor in Unsaturated Sand
Pullout Capacity of Block Anchor in Unsaturated Sand
复制标题
非饱和砂土中块锚的拉拔能力
DOI：
10.1061/40802(189)29
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
N. Al
中科院分区：
文献类型：
--
作者：
N. Al
块体锚杆是一种用来约束结构水平运动的界面单元。本文研究了在三种不同的水分条件下，水分条件(或饱和度)对埋入砂土中的块体锚杆抗拔能力的影响。所采取的方法包括实验工作和分析计算。试验工作是在实验室对埋在沙子中的0.15×0.15×0.15米混凝土砌块锚杆进行拉拔试验，深度为0.15米。沙子被存放在1.2x0.6x0.8m的盒子里，采用塞入法，以确保均匀和可重复的密度。对所使用的材料进行表征以了解其性能，并在使用前对所使用的设备进行校准。记录载荷及相应的水平位移和垂直位移。此外，还对破坏的土体进行了目视观测。实验结果与解析计算(朗肯、库仑和对数螺线理论)进行了比较。同时考虑了三维效应。研究发现，块式锚杆的抗拔能力高于板式锚杆。结果表明，湿度对块体锚杆的抗拔能力有显著影响。埋于非饱和(湿)砂中的块体锚杆的抗拔能力约为埋入干砂中的块体的两倍，而埋入饱和砂土中的块体的抗拔能力仅为埋入干砂中的块体的一半左右。这些结果对非饱和砂土中块体锚杆的分析和设计具有十分重要的意义。此外，这些也有助于评估埋藏在砂土中的块状锚杆在饱和度变化时的危险风险。
Block anchor is an interface element used to restrain horizontal movement of structures. This paper investigates the effect of moisture conditions (or degree of saturation) on the pullout capacity of block anchor embedded in sand at three different moisture conditions. The approach taken consists of experimental work, and analytical calculation. The experimental work is pullout tests, made in the laboratory, on 0.15 x 0.15 x 0.15m concrete block anchors embedded in sand, at a depth of 0.15m. The sand is deposited in a 1.2 x 0.6 x 0.8m box using a pluviation method to ensure a uniform and reproducible density. Materials used were characterized to find their properties, and the equipments used were calibrated before usage. The load and the corresponding horizontal and vertical displacements were recorded. In addition, visual observations were made on the failed soil body. The experimental results are compared with the analytical calculations (by Rankine, Coulomb, and log spiral theories). The 3-D effect was also considered. The block anchor was found to have higher pullout capacity than a plate anchor. The results show that the moisture condition significantly affects the pullout capacity of the block anchor. The pullout capacity of the block anchor embedded in unsaturated (wet) sand is about double that for the block embedded in dry sand, while that for the block embedded in saturated sand is only about one half of that for the block embedded in dry sand. These findings have very significant implications in the analysis and design of the block anchor embedded in unsaturated sand. Also, these have contributions to the hazard risk assessment of block anchors embedded in sand subjected to variations in degree of saturation.