频繁矿震下临近建筑物结构疲劳损伤及安全选址研究

Study on structural fatigue damage and safe site selection of adjacent buildings under frequent mine earthquake

为科学规划并有效利用矿区及周边土地资源,以某铁矿爆破作业及临近拟建设项目为研究对象,现场开展振动监测并结合修正后的撒道夫斯基公式得出振动速度等参数;针对单次爆破振动情形,依据不同类型建筑物在寿命周期内可正常使用对应的振动速度,得出爆破振动安全允许距离;针对频繁爆破振动情形,采用ANSYS有限元建模分析频繁爆破振动下建筑物的力学响应。结果表明:单次爆破振动对建筑物影响较小,仅对精密科研设备的正常使用造成一定影响,长期爆破微振动会使结构出现“软化”趋势和疲劳损伤,当振动次数超过20000次时(每天振动2次,约27 a),建筑结构压应力已超过破坏极限应力,从而预测建筑物使用寿命未达到设计年限要求;建议拟规划建设项目的选址距离振动源200 m以上(一般居住或办公用途)或1 km以上(精密仪器设备等用途)。

In order to scientifically plan and utilize the mining area and surrounding land,taking the blasting operation of an iron mine and the adjacent proposed construction project as the research object,the on-site vibration monitoring was carried out,and the vibration speed and other parameters were obtained by combining with the revised Sadolfsky formula.In view of single blasting vibration,according to the corresponding vibration speeds of different types of buildings in normal use within the life cycle,the safe allowable distance of blasting vibration was obtained.In view of frequent blasting vibration,the ANSYS finite element modeling was used to analyze the mechanical response of buildings under frequent blasting vibration.The results showed that the single blasting vibration had little effect on the building,with only certain impact on the normal use of precision scientific research equipments.The long-term blasting micro vibration would cause the“soften”trend and fatigue damage of structure,and when the number of vibration exceeded 20000 times(vibration twice a day,about 27 years),the compressive stress of the building structure had exceeded the ultimate stress of failure,so it was predicted that the service life of the building could not meet the design life requirement.It was suggested that the site selection of the proposed construction project should be more than 200 m away from the vibration source(general residential or official use)or more than 1 km(precision instrument and equipment and other uses).