重载铁路隧底结构病害特点及疲劳损伤机理分析

现场调查结果表明,隧底结构病害主要为隧底下沉、翻浆冒泥、侧沟外挤、混凝土破损和混凝土不密实,隧底病害连续长度多集中在3~9 m区间,围岩越差隧底结构病害越严重,隧底病害的影响因素主要为大轴重、围岩缺陷和地下水作用。基于通过疲劳寿命曲线预测铁路隧道结构疲劳损伤的方法,建立计算模型对重载线路疲劳损伤过程进行模拟分析。结果表明:在重载列车长期荷载作用下隧底结构道床、仰拱填充层和仰拱均依次出现了损伤;运行12年后重载线路道床最早出现损伤,轨枕下方损伤影响范围由上至下逐渐增大。

Disease Characteristics and Fatigue Damage Mechanism Analysis of Heavy Haul Railway Tunnel Bottom Structure

Field investigation shows that the main diseases of the tunnel bottom structure are subsidence of the tunnel bottom,rising soil,lateral trench extrusion,concrete damage and non-compactness of concrete.The continuous lengths of tunnel bottom diseases mostly concentrate in the range of 3~9 m.The worse surrounding rock is,the more serious the diseases of tunnel bottom structure are.The main inf luencing factors of tunnel bottom diseases are heavy axle load,surrounding rock defects and groundwater action.Based on the method of predicting fatigue damage for railway tunnel structure through fatigue life curve,a calculation model was established to simulate and analyze the fatigue damage process of heavy haul railway.The results show that under the long-term load of heavy haul trains,the damages of tunnel bottom structure roadbed,inverted arch f illing layer and inverted arch appear in turn.After 12 years of operation the damage of roadbed of heavy haul railway appears f irstly ,and the damage area under sleeper gradually increases from top to bottom.