Abrasion Behavior and Anti-Wear Measures of Debris Flow Drainage Channel with Large Gradient

Abstract

Debris flow gullies have high potential energy and geomorphic characteristics including a steep longitudinal slope and abundant loose material sources. They often experience debris flow with a strong impact force and a large instantaneous flow. Drainage engineering measures are most commonly used for mitigation in these gullies. However, the abrasion of drainage channels with large gradients (DCLG) is complex and strong because of the high-speed flushing of debris. In this study, the abrasion behavior of debris flow in DCLG is analyzed based on the kinematic characteristics and the theory of composite abrasive wear. Energy dissipation and anti-wear measures are suggested, and their effects are summarized with reference to a case study and in situ observation. The results show that there are four main types of wear morphology in drainage channels. The abrasion system of drainage channels shows the characteristics of system dependency, time dependency and multidisciplinary coupling. Energy dissipation and anti-wear measures include prefabricated reinforced concrete boxes as substrate, transverse roughening belts, adding a wear-resistant admixture, etc. The flow velocity of the debris flow is reduced by 5.7–37.1% after passing through the energy dissipation section. The distribution of abrasion and the mud depth show that the variation trend of the flow velocity in the channel is ”acceleration → deceleration → reacceleration“. According to tracking observations during two flood seasons, the energy dissipation and anti-wear measures are the most effective.

Effects of steel fibre type and dosage on abrasion resistance of concrete against debris flow

“…7a, e and 7f, which may be attributed to the middle parts of the concrete being more likely to contact with the coarse solid particle and to be severe collided and abraded. Field investigation results also confirm that the middle parts of the check dam and the drainage channel are the most vulnerable parts, they are prone to be damaged by debris flow abrasion [6].…”

“…The fluid phase in the debris flow is the medium that causes the motion and impact of coarse particles [1]. The motion drives the coarse particles move forward, such as suspending, rolling, and saltating, depending on the properties of the slurry in the debris flow, and thus the slurry concentration has an influence on the abrasion resistance of concrete [6]. In this study, the effects of slurry concentration and coarse particle content of debris flow on abrasion resistance of fibre-reinforced concrete are investigated.…”

“…The collision and friction of the coarse solid particle on the concrete surface will lead to severe abrasion damage of debris flow protective structures [3] and shorten their service life [4,5]. A previous study shows that the safety performance of the protective structure is reduced by 35-50% caused by debris flow abrasion [6]. The top of the protective structures and the bottom of the debris flow drainage channels are usually the most severe abrasion parts, which manifest as the spalling of surface mortar, the peeling or exposure of aggregates and the exposure or corrosion of reinforcing steel bars, etc.…”

“…Current research mainly focuses on the abrasion characteristics of concrete caused by water-borne sand [4], wind-borne sand [10] or ice [11], and very limited research on the debris flow abrasion resistance of concrete. Compared to other abrasive materials [12], debris flow shows characteristics including high bulk density, wide particle size distribution, coarse solid particle, and heterogeneous multiphase coupling, which leads to different abrasion failure mechanisms [6]. Among the influencing factors of debris flow abrasion, gravel particle content and slurry concentration are two of the most critical factors.…”

Discrimination of debris flow in narrow-steep type and wide-gentle type gullies in Wenchuan meizoseismal area

“…Several research teams have studied the type of debris flows in this region. Yang et al (2012) proposed the concept of narrow-steep channel type debris flow after studying 67 mudslide ditches that occurred in five areas of the Wenchuan meizoseismal area from 2008 to 2013 and analyzed their unique management difficulties and corresponding prevention and control countermeasures (Yang et al, 2015;Yang et al, 2020). Based on the characteristics of 13 debris flows along the Duwen Expressway in 2013, Han (2016) divided the channel-type debris flows into two categories, narrow-steep and wide-gentle, and discussed their disaster mechanism.…”