列车振动条件下古建筑群结构动力响应分析

为研究地铁列车振动对上方古建筑的影响规律,基于西安地铁4号线下穿和平门区段,建立不同行车速度组合工况有限元振动分析模型,用来分析和平门古建筑群的振动响应规律。并进行中国古建筑结构允许振动速度评价标准的比选、推导和确定,由结果可知:地铁单向或对向通过城墙时,不同车速对峰值位移几乎没有影响。城墙的峰值速度、加速度随着车速的增大而增大,在车速为80 km/h时达到最大。桥体在两种运行模式下的峰值位移、速度、加速度变化趋势与城墙相同,但最终值较大。综合比较,列车80 km/h对向行驶为最不利情况,此时城墙和桥体的速度、加速度分别为0.160,0.667 mm/s和0.679,2.998 mm/s^2。护城河桥的振动以竖直方向为主,而城墙在列车运营时主要呈水平方向振动。桥体的水平振动速度略大于城墙,且两者均小于容许水平振动速度,因此该地铁运营过程中可保证古建筑运营安全。

Dynamic Response Analysis of Ancient Buildings under Train Vibration Condition

In order to study the influence of subway train vibration on the ancient buildings above, a finite element model is established based on Xi'an Metro Line 4 underneath the city wall to analyze vibration response rules of the ancient buildings subject to different driving speeds and driving directions. The selection, derivation and determination of allowable vibration speed evaluation criteria for ancient Chinese buildings are also carried out. The results show that velocities have little effect on the peak displacement when subway trains are passing the city wall in one direction or opposite directions at different driving speeds. The peak velocity and acceleration of the wall increase with the increased speed, and reaches the maximum at the speed of 80 km/h. Meanwhile, the variation trend of peak displacement, velocity and acceleration of the bridge body in the two operating modes is the same as that of the city wall, but the final value is larger. Comprehensive comparison shows that the speed of 80 km/h is most unfavorable for the wall. The speed and acceleration of the city wall and the bridge are 0.160 mm/s, 0.667 m/s and 0.679 m/s~2, 2.998 m/s~2 respectively. The vibration of the bridge is mainly in the vertical direction, while the vibration of the city wall is mainly in the horizontal direction. The horizontal vibration velocity of the bridge is slightly larger than that of the city wall, and both are less than the allowable horizontal vibration velocities. Therefore, the safety of the ancient buildings can be guaranteed during the operation of the subway,