露天矿爆破地震波作用下框架建筑的动力响应

Dynamic response of the frame construction building to the open-pit blasting seismic waves

为研究露天矿爆破地震波作用下框架建筑的动力响应,开展了现场试验和数值模拟研究。试验测得爆破地震波参数和框架结构主体、砌体填充墙的固有频率及其动力响应;采用ANSYS程序计算出框架结构主体和砌体填充墙的固有频率,并分析了模型在爆破地震波作用下的动力响应。结果表明,填充墙体的固有频率高于建筑主体的固有频率,且接近于爆破地震波的输入频率,数值模拟计算的固有频率与现场测试结果一致;填充墙体的振动速度高于建筑主体的振动速度。虽然爆破地震波地表振动速率满足《爆破安全规程》,但框架结构主体和砌体填充墙固有频率的差异和频繁爆破震动使得砌体填充墙与梁、柱连接处产生裂缝。因此,评估露天矿周边框架建筑的振动安全性时,应考虑建筑的动力特性和露天矿爆破的特殊性。

This paper is aimed at introducing the results of our field monitoring test and numerical simulation for the response of the frame structure building to the impact of the open-pit blasting seismic waves. For our research purpose,we have done a field test and measured the vibration response and the blasting seismic wave parameters by using a DFC-1 hummer and M20 blasting vibration measurement system. At the same time,we have worked out the inherent frequency of the building and masonry filler wall via the DASP program and the modal analysis method. The field testing results demonstrate that the finite element model established in this paper proves rational with the inherent frequency of the frame construction building and the masonry filler wall being clarified by using the ANSYS program. What is more,we have made clear that the masonry filler wall tends to have two different working conditions,that is,the filler wall in the east-west direction and that of the north-south direction.In addition,the field test and the numerical simulation results show that： the natural frequency of the masonry filler wall is higher than the building＇s natural frequency,and is close to the input frequency of the blasting seismic wave. Besides,the simulation results also indicate that the stress contour of the masonry filler wall is also influenced at one time and eight times by the ANSYS,in which the frequent blasting or bursts tend to result eventually in a stress accentuation of the joints of beams and pillars. Although the vibration velocity of the blasting seismic wave can meet the specified need of the Safety Specifications of Blasting Operation,there still remains some gap in the inherent frequency between the filler wall and the main frame structure of the building and the frequent blasting vibration is likely to lead to the crack of the joint of the beams and pillars.Thus,the simulation and the testing results demonstrate that the dynamic response of the filler wall to the vertical blasting seismic wave turns out a bit more intense than that of the wall parallel to the blasting vibration wave. Based on the above analysis,it can be concluded that in the safety evaluation of the frame construction building around the open-pit mine,it is necessary to take into full account the dynamic response difference between the frame construction building and the masonry filler wall so as to reduce the blast frequency to the minimum extent.