依托深圳大芬水分洪箱涵暗挖隧洞工程,采用动力有限元软件建立了三维数值模型,研究了轻轨结构在隧洞爆破开挖下的响应特性.结果表明:随着爆心距增加,同一高程的轻轨结构峰值应力、位移和峰值振速逐渐减小;随着高程增加,同一立柱峰值应力逐渐减小,而峰值位移和峰值振速具有高程放大效应;隧洞已开挖区形成的空腔使上部轻轨结构的振速响应存在空腔放大效应和空腔阻尼效应.在此基础上,基于萨道夫斯基公式回归预测和仿真计算对隧洞掘进爆破单响药量进行优化,结果为:轻轨结构位于掌子面前面和后面,两种工况条件下的爆心距均为20.52、28.65 m,则在允许振速条件下的最大单响药量分别为1.8、6.0 kg和2.1、6.3 kg.
Numerical simulation of light rail structure under tunnel excavation blasting
Relying on the blasting project of the underground excavation tunnel of the Dafen water flood box culvert in Shenzhen,a three-dimensional numerical model is established utilizing the dynamic finite element software to study the response characteristics of the light rail structure under tunnel blasting excavation.The results of numerical simulation show that,with the increase of the blast center distance,the peak stress,displacement and peak vibration velocity of the light rail structure at the same elevation gradually decreases.As the elevation increases,the peak stress of the same column gradually decreases,while the peak displacement and peak vibration velocity have an elevation amplification effect.The space formed by the excavated area of the tunnel makes the cavity amplification effect and cavity damping effect exist in the vibration velocity response of the upper light rail structure.Furthermore,the maximum single-stage charge for tunnel excavation is optimized by the prediction of Sadovsky formula and simulation calculation.When the light rail structure is located in front and behind tunnel excavation working face,the detonation distance is 20.52 m and 28.65 m under these two working conditions,the maximum single-stage charge under the condition of allowable vibration velocity is 1.8 kg,6.0 kg and 2.1 kg,6.3 kg respectively.
万方数据
维普
