重载铁路隧道衬砌结构车致累积损伤演化规律

Evolution law of vehicle-induced cumulative damage of a heavy duty railway tunnel lining structure

为研究重载铁路马蹄形隧道车致损伤分布特征及演化规律,结合混凝土塑性损伤本构模型和规范推荐的混凝土拉压本构关系。以改进的Miner累积损伤理论为基础,建立了重载铁路单线马蹄形隧道-围岩耦合动力模型,研究了重载列车长期作用下隧道衬砌结构的损伤分布特征、累积损伤、损伤增量演化规律。结果显示:衬砌长期车致损伤主要分布在轨下仰拱处、仰拱与边墙交接处和仰拱填充与边墙交接处;边墙部分损伤由内侧向外侧演化,仰拱部分损伤由外侧向内侧演化;满载通行相比于空载最大损伤位置损伤量增大3.41倍;累积损伤及损伤增量都随着运营次数的增加而增大,且呈现非线性变化;隧道运营期间应在损伤增量进入显著增长区时,进行隧道衬砌的检测养护工作。

In order to study the distribution and evolution law of vehicle-induced damage in the horseshoe shaped tunnel of a heavy haul railway,a plastic damage constitutive model of concrete and the tensile and compressive constitutive relationship of concrete recommended by the code were combined.Based on the improved Miner cumulative damage theory,a coupling dynamic model of the horseshoe tunnel and surrounding rock for a single line of heavy-haul railway was established.The damage distribution characteristics,cumulative damage,incremental damage evolution and fatigue life prediction of tunnel lining structures under long-term action of heavy-haul trains were studied.The results show that the long-term vehicle-induced lining damage is mainly distributed in the invert of the track,the intersection of invert and side wall and the intersection of invert filling and side wall.The damage amount increased by 3.41 times compared with the maximum damage position with no load.Both cumulative damage and damage increment increase with operation times,and the change is non-linear.During tunnel operation,the tunnel lining should be inspected and maintained when the damage increment enters the area of significant increase.