越江隧道钻爆法施工最小岩石覆盖层厚度研究

越江隧道上覆最小岩石覆盖层厚度是决定隧道建设造价和安全的主要因素之一。以拟建的重庆朝天门两江隧道为例,采用工程类比法和3D弹塑性有限元数值模拟对隧道钻爆法施工的最小岩石覆盖层厚度进行了分析。工程类比分析表明,在正常水位条件下隧道最小岩石覆盖层厚度为22~27m;数值模拟分析表明,在历史最高洪水位条件下隧道最小岩石覆盖层厚度为23m。综合分析认为,两江隧道合理的最小岩石覆盖层厚度为23m。

Study on the minimum overlying rock thickness of a crossing-river tunnel by borehole-blasting method

The minimum overlying rock thickness of a crossing-river tunnel is one of the major factors, which determine the construction cost and the safety of the tunnel. For the Changjiang River and the Jialingjiang River tunnels to be built in Chaotianmen, Chongqing, elasto-plastic finite element numerical modelling through the engineering analogy method and the three-dimensional , the reasonable minimum rock overlying thickness is suggested Engineering analogy analysis shows that the minimum overlying rock thickness is 22m - 27m at regular water level and numerical analysis shows that the minimum overlying rock thickness is 23m at the historic highest flood level. The synthetical analysis result of engineering analogy and numerical modelling is that the reasonable minimum overlying rock thickness is 23m of the Changjiang River and the Jialingjiang River tunnel.