寒区隧道洞口衬砌开裂和道床冰害原因分析及整治

Analysis of Causes of Lining Cracking and Ballast Bed Freezing at Railway Tunnel Portal in Cold Regions and Their Countermeasures

为解决寒冷地区隧道内部产生的冰害问题,以东北地区某铁路隧道为例,采用综合分析的方法,对案例隧道洞口衬砌开裂、渗水以及道床冰害产生的原因进行研究,并提出相应的整治措施。研究结果表明:1)隧道洞口围岩衬砌开裂主要由围岩冻胀力引起,采用喷涂保温层+防火砂浆的保温措施以及锚杆补强和裂缝嵌补的结构措施可以有效避免衬砌的开裂;2)引起道床冰害的洞内水主要来源于洞口路堑的积雪融化水和仰拱局部渗水,采用双侧水沟布设电加热设施、洞口道床底部设置小型挡水坝并加设横向电加热设施和进口路堑位置及路堤零填段设置挡雪设施的措施可以有效解决道床冰害问题。

The causes of lining cracking,water-leakage and ballast bed freezing at portal section of a railway tunnel in Northeast China are analyzed by comprehensive analysis method;and then relevant countermeasures are proposed.The analytical results show that：1）The cracking of surrounding rock lining is mainly caused by frost-heave force of surrounding rock;and it can be effectively avoided by using insulation measure of spraying insulation layer ＋ fireproof mortar and structural reinforcement measure of anchor bolt ＋ crack filling.2）The water caused ballast bed freezing in tunnel is mainly derived from snow on portal cutting of tunnel and the local water-leakage of inverted arch;and it can be effectively avoided by setting electric heating facilities in ditches on both sides of the tunnel,setting a small dam and horizontal electric heating facilities under the bottom of ballast bed,and setting snow-covered facilities on portal cutting of tunnel and zero-fill section of embankment.