Estimation of Anchor Capacity in Net Protection System with Brake Frame for Debris Flow Based on Impact Energy

Abstract

New energy absorption devices have been developed for use in net-type debris flow protection systems. The capacity of the anchors in the system needs careful analysis because the anchors play a significant role in transmitting energy from the impacting debris to the ground. In this paper, an effective method is proposed for estimating the anchor capacity based on increasing energy levels and the effect of brake frames in the system. For this purpose, four test cases based on varying impact energy levels were developed and full-scale impact tests were performed. The maximum deformations and tensile forces developed in the system were recorded and analyzed. Thereafter, the performance of the net protection system in the presence and absence of brake frames was numerically analyzed using ABAQUS software, and the stress distribution in various system components was investigated. Based on the results of the full-scale impact tests and numerical analysis, a relationship between the total anchor capacity and impact energy level was established by considering the workability of the U-clips. This study demonstrates that approximately 40% reduced anchor capacity can be safely used for impact energy levels ranging from 50 to 200 kJ when brake frames are used in the system.