Abstract

Soil anchors are among the most widely used reinforcements to stabilize unstable soil mass or stabilize and anchor structures built in onshore and offshore regions. Anchors are generally installed in soil and rocky environments by penetration and embedment methods. These methods are classified into two main groups of grouted and mechanical anchors. In the present study, Expandable Mechanical Plate Anchors (EMPLAs), a new generation of mechanical anchors, are introduced and their bearing capacities are evaluated. EMPLAs can be implemented, locked, and activated in the soil more cheaply and with a lower driving force. Previous studies have validated the efficiency of these anchorages based on the experimental test results. Here, it is tried to evaluate the effect of properties of anchor plates such as their shape and curvature on the locking mechanism, as well as the ultimate bearing capacity of reinforcement and drop rate of locking force under a constant pullout speed rate. Furthermore, the ultimate bearing capacity of the anchors is calculated using two methods of 1) the well-known theories for calculating the tensile bearing capacity of plate anchors in cohesionless soil and 2) numerical modeling using finite element software. The results from both methods showed that the plate curvature intensity had a great impact on the plates opening rate and, consequently, faster locking and activation of the reinforcement at the higher embedment depth. Eventually, the effective zone of the soil at the top of the expandable plates during a 90° rotation of the plates and lockage of the reinforcement was monitored using the Particle Image Velocimetry (PIV) technique.

摘要

土锚是最广泛使用的加固物之一，用于稳定不稳定的土体或稳定和锚定在陆上和近海地区建造的结构。锚杆一般采用穿透和嵌入的方法安装在土壤和岩石环境中。这些方法分为灌浆锚和机械锚两大类。在本研究中，介绍了新一代机械锚杆可膨胀机械板锚杆（EMPLAs）并对其承载能力进行了评估。EMPLA 可以更便宜地在土壤中实施、锁定和激活，并且驱动力更低。以前的研究已经根据实验测试结果验证了这些锚固的效率。这里，试图评估锚板的形状和曲率等性能对锁定机构的影响，以及在恒定拉拔速率下钢筋的极限承载能力和锁定力下降率。此外，锚杆的极限承载力使用两种方法计算：1) 众所周知的计算板锚在无粘性土中的抗拉承载力的理论和 2) 使用有限元软件进行数值建模。两种方法的结果表明，板的曲率强度对板的开口率有很大的影响，因此，在较高的嵌入深度下，钢筋的锁定和激活速度更快。最终，