小净距新建隧道爆破对运营隧道的影响与控制

大帽山小净距新建四车道隧道扩建施工对邻近运营隧道的安全构成威胁。考虑运营隧道的初期支护作用,利用ANSYS/LS-DYNA软件建立新建隧道爆破效应在邻近运营隧道传播的数值计算模型,分析新建隧道爆破施工对邻近运营隧道的影响规律与药量控制标准。分析表明:小净距新建隧道爆破施工主要对邻近运营隧道迎爆面衬砌的侧墙顶部、中部及墙脚有重要影响,运营隧道的破坏首先是由迎爆面侧墙中部质点振速超过安全允许振速值造成;振速数值模拟结果与实测数据拟合公式计算结果基本一致。通过不同装药量爆破结果的分析,提出了新建隧道爆破的控制药量值。可为隧道扩建及小净距隧道施工提供参考。

Blasting Effect and Control of New Tunnel with Small Clear Space on Existing Operation Tunnel

Blasting vibration of the newly constructed Damaoshan four-lane tunnel posed a threat to the nearby operating tunnel. Considering the primary support of the operation tunnel, a numerical analysis model on blasting effect propagating near the operation tunnel from the newly constructed tunnel is established by the means of ANSYS/LS-DYNA software. The simulated results show that the maximum blasting effects on the operation tunnel are located near the side wall corner, arc corner and the middle of the side wall against the explosion source. The failure of the adjacent operation tunnel is mainly due to the vibration velocity larger than allowable safety vibration velocity. The numerical results of vibration velocity generally agree with that of the formula fitted by on-site measure data. The controlling value of maximum charge is recommended by the numerical results of the new tunnel blasting. The results are useful for the tunnel construction with small clear space and other similar problems.