Laboratory Study on Erosion of Vegetated HPTRM System under High-Speed Open-Channel Flow

Abstract

High-performance turf reinforcement mat (HPTRM) is a technology to strengthen the vegetation lining and enhance its anti-erosion capability. Existing studies on the erosion resistance of vegetated HPTRM systems are mainly based on large-scale tests and focus on permissible flow velocity and shear stress. In this study, a specially designed flume was used to generate high-speed open-channel flow and investigate the erosion process of a vegetated HPTRM system. In total, 48 samples of natural vegetation and three types of vegetated HPTRM systems were cultivated and tested under different slopes and discharges. Both continuous and discontinuous tests were conducted. During the tests, erosion depths, flow discharges, and flow velocities were recorded. The difference between the erosion rates of continuous and discontinuous tests indicates that the first flushing of the flow induced most of the erosion of the vegetated HPTRM system. The erosion processes of the samples displayed a decrease in erosion rate with an increase in erosion depth, which can be explained by the exposure of HPTRM and consequent increase of anti-erosion capability. The influences of flow discharge and the structure of the HPTRM on the erosion process we also investigated.