Influence of Aggregate Pollution in Truck Escape Ramps on Stopping Distance of Uncontrolled Vehicles

Abstract

Migration of fine materials such as soil from the roadbed and the ground will gradually pollute the aggregate in the arrester bed of truck escape ramps. However, there are few studies on the impact of aggregate pollution of the arrester bed on the stopping distance of runaway vehicles. This paper uses the discrete element method to study the influence of aggregates with different degrees of pollution on parking distance by taking silty cohesive soil as a typical pollutant. In this paper, the parking process of the uncontrolled vehicle on the arrester bed with different pollution levels was numerically simulated. The simulation results show that the uncontrolled vehicle’s parking distance increases with the contaminated aggregate’s soil content. The simulation results show that when the soil content in the contaminated aggregate is less than 15%, the increase in the parking distance of the uncontrol vehicle is less than 5%; when the soil content is 20–25%, the parking distance of the uncontrolled vehicle increases by more than 20%; and when the soil content is 30–35%, the parking distance of uncontrol vehicle increases by more than 50%. Different maintenance measures should be taken according to the increase in parking distance.

Analysis of the Load-Bearing Capacity of Pebble Aggregates

“…Figure 1 illustrates the fundamental design of the TER, which aims to decelerate trucks through the rolling resistance induced between the truck tires and the arrester beds, typically composed of pebble aggregates. Since the construction of the first TER in California, research on TERs has mainly focused on predicting brake drum temperatures [2], determining truck departure angles [3], exploring alternative materials for arrester bed pavements [4] and other related aspects. However, a significant knowledge gap exists regarding the load-bearing capacity of irregularly shaped, randomly distributed pebble aggregates in arrester beds, which directly influences the safety performance of trucks navigating through these beds.…”

Investigating the Influence of Varied Particle Sizes on the Load-Bearing Properties of Arrester Bed Aggregates

“…However, effective simulation of the driving process of out-of-control vehicles on the escape ramp, especially within the arrester bed, proves challenging with traditional mathematical modelling or road test analysis methods. The core issue arises from difficulty in analysing the loadbearing property of irregularly shaped pebbles randomly distributed within the arrester bed [6], consequently hindering the ability to predict the driving process of tyres within the aggregate. Therefore, the manner in which the load-bearing properties of pebble aggregates with different shapes and sizes is analysed has become a critical issue that must be addressed.…”