灌浆支洞爆破施工对既有隧洞的安全性评估

Safety Assessment of Grouted Branch Tunnel Blasting Construction on Existing Tunnels

文章以云南干河水库为例,旨在研究灌浆支洞爆破开挖施工对输水隧洞的影响。首先,介绍计算分析使用的方法与数值模型;其次,以控制灌浆支洞爆破强度为目标,使围岩质点振速不超过安全允许质点振速,进而评价岩体振动场及大湖山隧洞的力学响应和安全性;最后,以控制大湖山隧洞围岩振动不超过安全允许质点振速为目标,反算得到对应的灌浆支洞围岩质点振速峰值,将该值作为振动极值。结果表明,在灌浆支洞爆破施工时,围岩质点振动速度不超过该极值,即可确保灌浆支洞开挖爆破作业对输水隧洞造成的影响在允许的范围内。该方法具有一定的模拟精度及效果,可为工程设计和施工提供借鉴和指导。

Using the Ganhe Reservoir in Yunnan as an example,this paper aims to study the impact of grouted branch tunnel blasting excavation on water conveyance tunnels.First,the methods and numerical models used for the computational analysis are introduced.Next,the goal is to control the blasting intensity of the grouted branch tunnel so that the particle vibration velocity of the surrounding rock does not exceed the safe allowable particle vibration velocity.This approach is used to evaluate the vibration field of the rock mass and the mechanical response and safety of the Dahushan tunnel.Then,with the objective of ensuring that the surrounding rock vibration of the Dahushan tunnel does not exceed the safe allowable particle vibration velocity,the corresponding peak particle vibration velocity of the surrounding rock of the grouted branch tunnel is back-calculated,and this value is used as the vibration extremum.The results show that during the blasting construction of the grouted branch tunnel,as long as the particle vibration velocity of the surrounding rock does not exceed this extremum,the impact of the blasting excavation on the water conveyance tunnel remains within the permissible range.This method has a certain degree of simulation accuracy and effectiveness,providing a reference and guidance for engineering design and construction.