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考虑土体环境的相邻结构地震动碰撞试验与数值模拟研究

作者:完美论文网  来源:www.wmlunwen.com  发布时间:2019/10/29 8:04:56  

摘要:中国城市建筑有着许多相邻建筑物间距过小的情况,地震中发生碰撞破坏或倒塌的建筑引发的次生环境灾害亟需我们的重视。碰撞是导致结构破坏甚至倒塌不可忽视的因素,对结构碰撞机理进行分析研究,能清楚地定义碰撞作用对结构动力反应和地表环境的影响,有针对性地采取控制碰撞的措施,从而达到预防碰撞破坏或倒塌带来的次生环境灾害的目的。

本文首先说明了关于相邻结构碰撞问题和考虑土体环境的研究现状,阐述了结构碰撞的原因和类型,以及结构碰撞研究方法的发展,详细介绍用于模拟结构碰撞的两种方法,对多种模型的建模方法和参数给定方式进行了讨论,比较了不同理论模型的优势和劣势,同时对适用于研究结构碰撞的有限元结构分析软件进行了介绍。

根据相似原理制作了比例为1:30的等高缩尺模型,按照规范要求选取了两条天然地震动与一条人工地震动进行了振动台试验,研究了考虑土体环境与不考虑土体环境两种情况下相邻建筑结构地震动碰撞的位移动力反应、速度动力反应及加速度动力反应。

通过ABAQUS依据振动台试验建立了相应的数值模型,将数值计算结果与振动台试验结果进行对比分析,讨论了结构碰撞对地表环境的影响。最后采用经过验证的数值模拟方法建立4组模型,对4种方位布置条件对结构碰撞及其造成的地表环境影响进行分析,并提出相应的地表环境破坏控制措施。得出结论:

(1)考虑土体环境时,在地震过程中,土体与结构之间会产生相互作用。相邻建筑结构碰撞的位移动力反应被放大,速度动力反应与加速度动力反应被削减,结构受到的惯性作用会更加明显,并且其位移动力反应与加速度动力反应会出现明显滞后的现象。

(2)不考虑土体环境时,相邻建筑结构由于自振周期有差异而发生碰撞,考虑土体环境时土体放大了这种差异,使得结构碰撞次数增加。

(3)数值模拟结果与振动台试验结果有较高吻合度,数值模拟基本可以的再现试验现象,验证了数值模拟的可行性与合理性。

(4)刚度越大的结构地震效应越小,对地表环境的破坏越轻,并且,结构-土环境下地表位移明显小于自由场环境下地表位移。

(5)不同方位布置条件对相邻建筑结构地震动碰撞动力特性产生的影响各异。相邻建筑结构的短边与短边相邻并且处于远震源位置时,碰撞对其造成的影响更小,利于灾变控制。

(6)通过四种方位布置对土体环境影响分析,C、D两组短边与短边相邻的模型的地表位移稍微低于A、B两组长边与长边相邻的模型,说明C、D两组模型的布置方式灾变影响更小,更有利于保护土体环境,A、B两组模型的布置方式则需要采取一定灾变控制措施。

(7)碰撞会导致相邻结构受到瞬间的冲击力,这种冲击力会加剧土体环境受到的作用力,若结构的震中距恰好在5km-400km内,并且震级5.5级-8.5级之间,则会大大增加土体液化的风险,造成极大的环境灾害。

There are many adjacent buildings inChinese urban buildings which are too close. The secondary environmentaldisasters caused by collision and collapse or collapse in the earthquake needour attention. Collision is a factor that can not be ignored in structuraldamage or even collapse. The analysis of the mechanism of structural collisioncan clearly define the impact of the impact on the dynamic response of thestructure and the soil environment, and take measures to control the collision,so as to prevent the secondary environmental disasters caused by the collisiondamage or the collapse zone.

In this paper, the present situation of thecollision problem of adjacent structures and the consideration of the soilenvironment was explained. The reasons and types of structural collision and thedevelopment of structural collision research methods were expounded. Twomethods used to simulate the structure collision were introduced in detail, andthe modeling method and the parameter given method were discussed in thispaper. The advantages and disadvantages of different theoretical models werecompared, and the finite element structural analysis software suitable forstudying structural collision was introduced.

According to the similarity principle, ascale model of equal height at 1:30 was made. According to the requirements,two natural ground motions and one artificial ground vibration were selected tocarry out a shaking table test. The dynamic response and velocity dynamics ofseismic dynamic collision of adjacent building structures under two conditionsof soil environment and non consideration of soil environment were studied. Thereaction and the dynamic response of the acceleration. The correspondingnumerical model was established by ABAQUS based on shaking table test. Theresults of numerical calculation and shaking table test were compared andanalyzed, and the impact of structural collision on the surface environment wasdiscussed. Finally, 4 groups of models were established by the verifiednumerical simulation method, and the impact of the 4 azimuth layout conditionson the structure collision and the surface environment was analyzed, and thecorresponding measures for the damage control of the surface environment wereput forward. Come to conclusion:

(1) When considering the soil environment,the interaction between soil and structure will occur during the earthquake.The dynamic response of the adjacent building structure is amplified, thevelocity dynamic response and the acceleration dynamic response are reduced,the inertia effect of the structure will be more obvious, and the displacementdynamic response and the acceleration dynamic response will appear obviouslylagging.

(2) When the soil environment is notconsidered, the adjacent building structures collide because of the differenceof the self vibration period. When the soil environment is considered, the soilmass magnifies the difference, which makes the number of structural collisionsincrease.

(3) The numerical simulation results havehigher coincidence with the shaking table test results, and the numericalsimulation can be basically reproduced test phenomenon, and the feasibility andrationality of the numerical simulation are verified.

(4) The smaller the structure, the smallerthe seismic effect, the lighter the damage to the surface environment, and thesurface displacement in the structure soil environment is obviously less thanthe surface displacement under the free field environment.

(5) The influence of different azimuthlayout conditions on the impact dynamic characteristics of adjacent buildingsis different. When the short and short edges of adjacent buildings are adjacentto each other and are located at far source locations, the impact of collisionson them is smaller, which is conducive to disaster control.

(6) By analyzing the influence of fourazimuth arrangement on the soil environment, the surface displac

关键词:相邻结构碰撞;土体环境;振动台试验;数值模拟;灾变控制

Adjacent structure collision; Soilenvironment; Shaking table test; numerical simulation; Calamity control

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