# Study on the High-Speed Penetration and Shear Failure Mechanism of Beach Sand

## TL;DR

This study uses simulations to understand how beach sand behaves under high-speed penetration and shear forces, revealing how sand's resistance changes with speed.

## Contribution

The paper introduces a calibrated discrete element method to analyze beach sand's high-speed failure mechanisms with high accuracy.

## Key findings

- The bearing capacity of beach sand increases significantly with higher penetration rates.
- Shear torque decreases sharply when shear speed exceeds 4 m/s due to reduced particle contact.
- Simulations showed a 3.27% error in angle of repose predictions compared to experiments.

## Abstract

In this paper, the contact parameters of beach sand are calibrated based on the discrete element method and the optimal design method, and the obtained parameters by calibration are used as input for the angle of repose simulation. The relative error between angle of repose simulation results and experimental results is 3.27%. Based on the penetration and shear tests, simulation models were constructed to study the pressure shear failure mechanism of beach sand under high-speed conditions. The high-speed penetration simulation shows that with the increase of the penetration rate, the influence area of the sinkage plate gradually increases, and the stress of sand particles also increases. When the penetration rate increased from 0.5 m/s to 8 m/s, the pressure on the plate increased 12.7 times, indicating that the bearing capacity of the sand increased significantly with the increase of the penetration rate. The high-speed shear simulation shows that in the stable shear stage, the average shear torque initially increases slightly with the increase of speed, and then decreases significantly when the speed exceeds 4 m/s. This is because as the shear rate increases, the disturbance of the soil by the shear plate increases, the velocity of soil particles increases, resulting in a decrease in the number of soil particles in contact with the shear plate, thereby reducing the shear torque.