不同速度列车脱轨撞击盾构隧道的动力损伤特性

Dynamic Damage Characteristics of Shield Tunnel Impacted by Train Derailment at Different Speeds

为研究不同速度列车脱轨撞击盾构隧道的动力损伤特性,基于撞击动力学以及混凝土塑性损伤理论,建立列车—隧道—围岩的非线性接触动力有限元模型,分析120,200,300 km·h-1这3种列车脱轨速度下,列车撞击盾构隧道时的撞击力特征以及隧道衬砌的损伤演化和分布规律。结果表明:3种速度列车脱轨时的撞击力变化规律一致;随着列车脱轨速度的增加,撞击力分量峰值均呈非线性增大;将撞击过程分为初始撞击、撞击耗能和稳定撞击3个阶段,隧道衬砌管片拉、压损伤值均在初始撞击阶段达到峰值,之后损伤的发展主要表现为损伤面积的不断扩大;衬砌管片外表面的损伤发展略滞后于内表面;压缩损伤的分布基本呈现出沿隧道轴向大于环向的"梭形"形态,而拉伸损伤的分布则更加广泛,损伤较大值(大于0.9)产生区域也更加分散;与压缩损伤相比,拉伸损伤更易导致衬砌发生大范围破坏;在较低脱轨速度下隧道衬砌即会产生较为严重的损伤,而损伤面积则随着列车脱轨速度的增加显著增大。

In order to study the dynamic damage characteristics of shield tunnel under the impact of train derailment at different speeds, based on impact dynamics and the plastic damage theory of concrete, a nonlinear contact dynamic finite element model of train-tunnel-surrounding rock was established. The characteristics of impact force as well as the damage evolution and distribution of tunnel lining were analyzed under three different train derailment speeds of 120, 200 and 300 km·h-1. Results show that the variation law of the impact force under three train derailment speeds is consistent. With the increase of train derailment speed, the peak values of impact force components increase nonlinearly. Based on this, the impact process can be divided into three stages: initial impact, impact energy consumption and stable impact. The tensile and compressive damage values of tunnel lining segments reach their peaks at the initial impact stage, and the development of the damage afterwards is mainly manifested as the continuous expansion of the damage area. The damage development on the outer surface of lining segment lags slightly behind that on the inner surface. The distribution of compression damage basically presents a"shuttle"shape, that is, the distribution along the axial direction of the tunnel is greater than that in the circumferential direction, while the distribution of tensile damage is more extensive, and the area where the larger damage value(greater than 0.9) occurs is more dispersed. Compared with compression damage, tensile damage is more likely to lead to a wide range of lining failure. In addition, the tunnel lining will have more serious damage at a lower derailment speed, and the damage area will increase significantly with the increase of train derailment speed.