地铁装配式外置槽道火灾下温度分布与温度应力数值模拟

Numerical simulation of temperature distribution and thermal stress in assembled external channel of metro under fire

为研究地铁装配式外置槽道在火灾场景下的安全性能,采用ABAQUS有限元软件建立混凝土管片、纵向连接螺栓以及外置槽道的数值模型,模拟计算其在碳氢(HC)升温曲线下的温度与温度应力分布规律。研究发现:外置槽道的存在会显著提高纵向连接螺栓的温度,且手孔处与挂耳紧贴的混凝土面的温度分布规律明显区别于无槽道情形,温度高出约100℃;外置槽道对手孔侧边和远离手孔混凝土的温度影响不大,但会加速紧贴面混凝土与纵向连接螺栓裸露端的升温;外置槽道进一步加剧了纵向连接螺栓与周边混凝土温度的不均匀性,从而产生额外的温度应力,但仍在允许范围内。

In order to study the safety performance of the subway assembled external channel in the fire scenario,the ABAQUS finite element software was used to establish the numerical model of tunnel segments,longitudinal connection bolts and external channel.The temperature and stress distribution of the new structure under the HC heating curve were obtained.The study showed that the existence of external channel could significantly improve the temperature value of longitudinal connection bolts.Compared with the results without external channel,the temperature distribution on the contact surface of the hand hole which close to the hanging ear was significantly different,the temperature value was about 100℃higher.The external channel had little influence on the temperature of the concrete which at the side of the hand hole and away from the hand hole,but it could accelerate the heating of the longitudinal connection bolts which at the exposed end as the same as the contact surface.Additional thermal stress was generated as the external channel fur-ther increased the temperature inhomogeneity between the longitudinal connection bolts and the surrounding concrete,but the final result was still within the safe range.