Load transfer behavior and interference effect of load distributive compression anchor in residual soil

As ground anchors are widely used to stabilize various structures, load distributive compression anchor (LDCA) is gaining popularity owing to their high load-bearing capacity and ease of removing strands. Unlike conventional anchors, an LDCA consists of multiple anchor bodies, thus allowing the distribution of the load among them. In addition, interference effects that differentiate the behavior of LDCA from that of single compression anchor are induced. These effects must be considered when designing an LDCA; however, the lack of research on its supporting mechanism has led to LCDA design being based on conventional criteria and experience. Furthermore, existing studies have not focused on the behavior of LDCA in soil, which is more vulnerable than in rock. This study proposes a physical model test that evaluates the load transfer mechanism of an LDCA. A series of pull-out tests is performed on an LDCA installed in residual soil to investigate the behavior of the LDCA under various conditions, by varying parameters such as the total anchor length, number and spacing of anchor bodies, and loading conditions. The test results show that the movement of the upper anchor body causes a tensile load on the grout and additional grout–soil shear stress on the lower anchor body, which reduces the ultimate bearing capacity of the LDCA. Moreover, the test results reveal that the interference effect between anchor bodies increases as the spacing decreases, thus resulting in a greater reduction in the ultimate bearing capacity. The findings of this study are anticipated to develop the basis for the design and application of LDCA.