Study on transient dynamics of piers under the impact of debris flow

Abstract

Because of the climate warming and the serious ecological damage of the valley slope, the frequency of debris flow in the valley is increasing frequently. The solid deposits in the debris flow are, transported at high speed under the action of water flow and self-gravity, have a great impact on the piers along the line, which greatly destroys the integrity and stability of the pier. Through the theoretical analysis and numerical simulation of debris flow, the transient dynamic response of the pier under the impact of debris flow is analyzed. It is concluded that the pier is subjected to the punching and shearing form load, and the impact damage of the coarse solid particles in the debris flow to the pier is more obvious. The pier displacement reaches the maximum at the second impact of the debris flow; the maximum displacement is 10.9mm, which appears at the 5m above the bottom of the pier. A tensile stress concentration zone appears at the bottom of the pier, and the maximum tensile stress is 1.84MPa, which exceeds the concrete strength of the pier and so we can take corresponding measures to guard against this problem so as to ensure the safety of bridge structure.