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为提高小净距隧道先行洞在后行洞爆破开挖时的安全性,需要对先行洞在后行洞爆破荷载作用下的动力响应做理论研究。运用有限元的基本理论,采用ABAQUS软件对小净距隧道爆破开挖对相邻洞的影响进行了研究。重点研究了五级围岩条件下爆破对相邻洞的影响,分别就不同开挖步骤情况下既有隧道的振动速度和塑性区进行了分析。结果表明,当后行洞采用侧壁导坑法分五步爆破开挖时,第一步爆破开挖对先行洞的影响最大;小净距隧道内拱腰、内拱脚位置受相邻洞爆破影响最大,最易发生破坏,施工时应加强监控量测。
In order to improve the safety of the first hole of the small clear distance tunnel in the blasting excavation of the succeeding tunnel, the dynamic response of the preceding tunnel under the blasting load of the succeeding tunnel needs to be studied theoretically. By using the basic theory of finite element method, the influence of blasting excavation on the adjacent hole with small clear distance tunnel was studied by ABAQUS software. The influence of blasting on adjacent holes under five conditions of surrounding rock is studied emphatically. The vibration velocity and plastic zone of the existing tunnel under different excavation steps are respectively analyzed. The results show that the first step of blasting excavation has the most influence on the advance hole when using the side-guide method to excavate the back-hole. In the small-clear distance tunnel, the arch waist and the internal arch feet are affected by the adjacent holes Blast the impact of the most vulnerable to damage, construction should be strengthened monitoring and measurement.