水工隧洞爆破施工对边坡影响的数值分析

Numerical Analysis of Blasting Construction Effect on Slope in Hydraulic Tunnel

水工隧洞爆破开挖的振动波不仅会造成洞身岩体变形,还会继续传播影响邻近边坡。采用数值模拟方法,以在建工程为例,研究爆破振动对边坡不同部位的应力应变影响。结果表明,初爆瞬间动力荷载沿圆周作用于隧洞周壁面并向外扩散,当压应力波扩散至坡面后发生反射并形成拉应力波,拉应力区范围先增后减。在爆破过程中,边坡中各部位应力值呈现先增后减的特征,且坡面的位移较坡脚更大。通过振动效应分析发现,无论在边坡坡脚或坡顶,振速峰值随着距坡脚和坡肩距离增大而减小,振动频率则反之,同时坡顶振速明显大于坡脚。

The vibration wave caused by blasting excavation of hydraulic tunnel not only caused deformation of rock mass, but also affected adjacent slopes. Taking construction projects as an example, the effect of blasting vibration on the stress and strain of different parts of slope was studied based on numerical simulation method. It was indicated that the initial burst instantaneous dynamic load acted on the circumferential wall surface of the tunnel and spread outward, and that the , and area of tensile stress increased first and then minus when the compressive stress wave spread to the slope and developed the tensile stress wave. In the process of blasting, the stress value of each part of the slope was characterized by increasing first and then decreasing, and the displacement of slope was larger than that of slope foot. Through the analysis of vibration effect, it was found that the peak of vibration velocity decreased with the increasing distance between the slope foot and shoulder of the slope, while the vibration frequency was the opposite that the speed of the slope crest was obviously higher than foot.