场地类别对装配式地铁车站结构地震响应的影响

Seismic Responses of Prefabricated Metro Stations Built at Different Sites

为研究装配式地铁车站结构在不同场地条件下的地震响应,基于有限元软件,建立地层-装配式地铁车站结构三维静动力耦合非线性有限元分析模型,分析不同场地类别、不同地震动峰值加速度以及竖向地震动条件下装配式地铁车站结构的地震响应,并给出装配式地铁车站的加速度、变形、应力及塑性损伤的变化规律。分析表明:1)场地类别由Ⅱ类变为Ⅲ类时,车站结构顶底间最大相对水平位移与接头张开角逐渐增大,且增长幅度变大,但接头张开角仍较小(<0.10°),验证了接头的稳定性和安全性;2)在Ⅲ类场地条件下,拱腰、拱肩以及侧墙上下端附近的围护结构等位置易出现塑性损伤;3)相比单向水平地震动,增加竖向地震动会显著增大装配式地铁车站结构的变形、应力、接头张开角及塑性损伤。总体来看,在Ⅱ类场地条件下,输入地震动峰值加速度分别为0.1g和0.2g时,结构基本处于弹性工作状态;在Ⅲ类场地条件下,输入地震动峰值加速度为0.4g时,结构处于弹塑性工作状态且塑性区体积较大。

To investigate the seismic response of a prefabricated metro station in different site conditions, a threedimensional static and dynamically-coupled nonlinear finite element model of a prefabricated metro station is established based on finite element software. Then, the seismic response of the fabricated metro station under different site conditions, peak accelerations of seismic waves, and vertical seismic waves is systematically analyzed. Finally, the acceleration, deformation, stress, and plastic damage laws of the fabricated metro station are obtained. The results demonstrate that:(1) The horizontal displacement difference between top and bottom of the station structure and the opening angles of the joint gradually increase as the site conditions change from category Ⅱ to category Ⅲ, and the growth rate gradually increases, but the opening angles of the joint are maintained at a low level(less than 0.10°),verifying the stability and safety of the joint.(2) The waist and shoulder of the top arch and the envelope structure near the sidewall are prone to plastic damage in site condition category Ⅲ.(3) Compared with single-horizontal seismic waves, the deformation, stress, opening angles of joint, and plastic damage of the fabricated metro station will be significantly increased by increasing the horizontal seismic waves. Generally, under site condition category Ⅱ and an input peak acceleration of seismic waves of 0.1g and 0.2g, the structure is basically in a flexible working state;whereas under site condition category Ⅲ and an input peak acceleration of a seismic wave of 0.4g, the prefabricated metro station is in a plastic working state and the area of the plastic zone is large.