爆破开挖振动下既有大型储油罐的动力响应

Dynamic response of existing large oil storage tank under blasting excavation vibration

针对既有大型储油罐近区基础爆破开挖中的安全问题,采用ANSYS/LS-DYNA的隐式-显式顺序求解方法,结合流固耦合算法,研究了爆破振动下大型储油罐的动力响应规律。分析了罐壁不同位置的质点振速,由于质点振速分布情况较为复杂,不宜用局部质点振速判断罐壁危险点;总结了罐壁上应力的分布规律,结果显示爆破振动对储油罐的影响主要集中在迎爆侧下部,且在罐壁迎爆侧高度为3 m左右的位置最易发生象足屈曲;分析了不同频率爆破振动作用下满载储罐罐壁的质点振速,结果表明在爆破振动主频范围内,载荷频率远大于储罐固有频率条件下,罐壁上质点振速随着爆破振动频率的降低呈减小趋势;建立了储油罐罐壁质点振速与罐内液面高度的关系,结果表明降低液面高度可以有效提高储油罐的爆破振动安全阈值,爆破施工中邻近储罐储液高度不宜高于10 m。

Aiming at the safety problem of existing large oil tank under near base blasting excavation,the dynamic response of large oil tank is analyzed by numerical simulation method,based on the implicit-to-explicit sequential solution procedure and the fluid solid coupling algorithm of ANSYS/LS-DYNA.different positions are obtained,by which it is not appropriate to determine the dangerous point of the tank wall because the distributions of the particle vibration velocities are very complex.The dynamic stress distribution on the tank wall is summarized,and the results show that the influence of blasting vibration on the oil tank is mainly concentrated on the lower part of the explosion side,and that the elephant foot buckling deformation is most likely produced at the height of 3 meters on the detonation side of tank wall;The particle vibration velocity of the tank wall under different frequency of blasting vibration is analyzed.The results show that in the main frequency range of blasting vibration,the particle vibration velocity on the tank wall decreases with the decrease of blasting vibration frequency if the load frequency is much larger than the natural frequency of the tank;The relationship between the particle vibration velocity and the liquid level in the tank is established,and the results show that lowering the height of liquid level can effectively improve the safety threshold of blasting vibration of the oil tank,and the storage liquid height of adjacent storage tanks should not be higher than 10 m for blasting operations.