研究目的:以成昆铁路复线沈家坝1号隧道为依托,进行隧道爆破施工对初支混凝土损伤的影响试验,综合试验和数值模型,分析初支混凝土的受损情况,得出初支混凝土的安全振速阈值,确保隧道施工时初支混凝土的安全性与可靠性。
研究结论:(1)在沈家坝1号隧道内进行爆破振动监测试验,回归分析萨道夫斯基经验公式,结合隧道施工的数值模型,将所得结果与萨道夫斯基经验公式推算的结果对比分析,将合振速萨道夫斯基经验公式修正为v_合=78×(3Q/R)^1.38;(2)以现场施工采用的C25初支混凝土为对象进行爆破作用下初支混凝土受损试验,测定不同龄期混凝土的损伤值,得到不同龄期混凝土的安全振速阈值;(3)本文得出的初支混凝土的技术参数对其他同类工程具有指导意义。

Research purposes:Relying on the Shenjiaba No. 1 tunnel of the Chengdu-Kunming railway double line, this paper establishes an experiment on the damage of the initial concrete when the tunnel is drilled and blasted, to analyze the damage of the initial concrete by comprehensive experiments and numerical values. The model is calculated to obtain the safe vibration velocity threshold of the initial concrete to ensure the safety and reliability of the initial concrete during tunnel construction.
Research conclusions:(1) The blasting vibration monitoring test is carried out in Shenjiaba No.1 tunnel. The Sadovsky empirical formula is analyzed by regression analysis. Combined with the numerical model of tunnel construction, the obtained results are compared with the calculated results of Sadovsky empirical formula, and the Sadovsky empirical formula of combined vibration speed is corrected to v_合=78×(3Q/R)^1.38. (2) Taking C25 initially supported concrete used in site construction as the object, the damage experiment of initially supported concrete under blasting is carried out, the damage value of concrete at different ages is measured, and the safe vibration velocity threshold of concrete at different ages is obtained. (3) The technical parameters of the initial concrete from this paper have guiding significance for other similar projects.