钻爆法通常是新奥法隧道开挖所采用的最为经济、有效的方法之一。当隧道周边存在重要管线或者构筑物需要保护的情况,传统的钻爆法由于振动过大,可能会被限制,甚至禁止实施。采用机械开挖虽对周边影响较小,但其适用范围一般在围岩强度<80 MPa。介绍的宁海38省道项目,新奥法隧道开挖过程中实际围岩强度与业主提供的地勘资料差异极大,围岩强度最高达160MPa。致使最初拟定的机械法几乎无法实施,在反复尝试和比较多种方案(如:静力爆破、气爆法等)之后,选择了控制爆破与机械法协同开挖,并通过严格的安全验算,在确保输水隧洞安全的同时,满足了进度的要求。 Drilling and blasting is usually one of the most economical and effective methods for tunnel excavation in the New Austrian law. When there are important pipelines around the tunnel or structures need to be protected, the traditional method of drilling and blasting may be limited or even prohibited due to excessive vibration. Though mechanical excavation has less influence on the surrounding area, its application scope is generally less than 80 MPa in surrounding rock strength. The introduction of the Ninghai 38 provincial highway project, the actual strength of surrounding rock during the excavation of the New Austrian Tunnel and the geological data provided by the owners vary greatly, and the surrounding rock strength is as high as 160 MPa. As a result, the mechanical method originally proposed was almost impossible to be implemented. After repeated attempts and comparisons of various schemes (such as static blasting and gas explosion method), controlled blasting and mechanical excavation were selected and rigorous safety checks were conducted. In ensuring the safety of water tunnel at the same time, to meet the requirements of the progress.