路堑爆破对人行通道的影响分析

Analysis the influence of cutting blasting on pedestrian passage

为降低爆破振动的危害,保证近邻建(构)筑物的安全,结合新建徐盐铁路徐淮场路堑石方爆破工程,利用FLAC3D软件建模计算,应用数值模拟方法和现场实测波形,对路基下方近邻人行通道在爆破荷载作用下的动力响应进行研究。数值建模按实际工程施工情况分5个台阶逐层开挖,从应力、位移、速度响应等方面对人行通道安全进行分析。研究结果表明:通道应力在爆破振动作用下发生重分布,在第一个台阶爆破开挖过程中人行通道围岩产生的动力响应最为显著,应力最大值出现在人行通道左下角,约467kPa;第一个台阶开挖人行通道迎爆侧边墙处z方向速度达到最大值,为2.7cm/s;爆破荷载作用下人行通道顶部位移最大为2.9mm。因此,施工过程中进行安全支护时应分阶段、分部位区别对待,采用合理的爆破参数,并对应力、位移和速度较大的部位加强监测。

To reduce the hazards of blasting vibration and ensure the safety of nearby buildings(structures),combined with the blasting project of the Xuhuaichang cutting on the Xuyan railway,using FLAC 3D software model calculations,applying numerical simulation methods and field measurement waveforms,the dynamic response of the pedestrian passage below the roadbed under blasting load was studied.The numerical model is carried out by excavating layers of 5 steps according to actual construction conditions,the analysis of the safety of pedestrian passage from the aspects of stress,displacement and speed response.Research indicates that the stress of tunnel body is redistributed under the action of blasting vibration.The dynamic response of surrounding rock of pedestrian passage is the most significant during the excavation of the first step blasting.The maximum stress in the hole appear in the lower left corner of the pedestrian passage,about 467 kPa;the speed of the z-direction at the first-step excavation of the pedestrian passage side wall is 2.7 cm/s;the maximum displacement at the top of the pedestrian passage under the blasting load is 2.9 mm.Therefore,safety support during the construction process should be treated in stages and at different locations.Reasonable blasting parameters should be used,and monitoring of locations where stress,displacement,and velocity are relatively large should be strengthened.