基坑机械拆撑振动对邻近历史建筑的影响  

Influence of machine-made vibration and shock on the historic buildings near the foundation pit in the support-demolishing operation

作　　者：邵光辉[1] 周年强[1,2] 赵志峰 樊凤凯[3] 

机构地区：[1]南京林业大学土木工程学院,南京210037 [2]同济大学结构工程与防灾研究所,上海200029 [3]中煤隧道工程有限公司,江苏徐州221000

出　　处：《安全与环境学报》2017年第6期2119-2124,共6页Journal of Safety and Environment

基　　金：江苏高校优势学科建设工程项目(PAPD2015)

摘　　要：深基坑混凝土支撑结构破碎拆除时产生的施工振动会引起坑周一定范围内的地面振动,当基坑紧邻需要保护的历史建筑时,对振动的影响评估与控制显得尤为重要。通过对古旧建筑物密集的苏州市老城区深基坑工程的机械拆撑振动实测,讨论了振动波传播途径、频谱与时域特征和衰减规律。根据基坑拆撑振动波的传递特点,提出了拆撑振动在坑外地表传播的衰减方程。讨论了基坑拆撑振动对周边历史建筑的影响范围。结果表明:机械拆撑振动主频为破碎锤冲击频率的倍频,提出的振动衰减方程能够较好地描述坑周地表振动传播规律,可用于预测对周边建筑物的影响。机械拆撑施工时,对于保护性历史建筑,距离基坑的最小安全距离为24.5 m;对一般振动敏感、具有保护价值的建筑,最小安全距离为4.8 m。The paper is inclined to make an investigation and examination of the vibration impact produced in demolishing the concrete supports by the hydraulic breaker in a certain range or distance. We have been keeping a vibration monitor and observation at different building sites in various distances to the pit edge,in the process of the pit support demolishing. In proceeding with our research,we have investigated the vibration time-history for the different vibration sources and the different propagation wave directions. We have also been trying to discuss the vibration wave spectrum and the temporal-spatial behaviors and the decaying regulations caused by such demolishing actions. Furthermore,based on the wave propagation characteristics of the pit support demolishing,more detailed study of the affected demolished foundation structures should be taken as an entire vibration source,and the distance from the hydraulic breaker impacting points around the foundation pit edge as the vibration source radius,so as to build up a ground vibration wave propagation equation for the pit outside ground vibration. The results we have worked out reveal that the vibration decays gradually while transmitting the straight concrete beams of the pit support directly,and decays significantly while transmitting in the broken concrete beams. The dominant frequency derived from the supporting beam demolishing action should be equal to the frequency multiplication of 8. 5 Hz generated from the hydraulic breaker impact. The peak value of the amplitude and powder tends to be in the frequency of 51 Hz. The vibration peak velocity affected by the ground vibration wave propagation equation can be found well in accord with the artificial measuring results. For example,the historic buildings should be laid out at least 24. 5 m away from the pit edge. It is a common sense that vibration or protected buildings should be kept away at least 4. 8 m away from the pit edge,which safety distance should be taken as a pit demolishing engineering reference li

关 键 词：安全工程 基坑施工 拆除施工 振动传递 振动影响 历史建筑 

分 类 号：X839.1[环境科学与工程—环境工程]