浅埋暗挖洞桩法参数敏感性分析

针对浅埋暗挖洞桩法理论分析落后于工程实践的实际情况，依据地下结构设计计算理论的地层--结构法，以有限单元法作为分析手段，建立三维计算模型，系统开展了浅埋暗挖洞桩法施工过程的数值模拟，以及参数变化对洞周围岩稳定性和位移场的影响分析。结果表明：浅埋暗挖洞桩法用于大断面洞室或超浅埋洞室暗挖施工时，洞周围岩稳定性良好，并可有效控制地表沉降。洞室跨度为14 m左右时控制地表沉降的效果最好；在不同埋深条件下控制地表沉降的效果基本相同；洞室高度的影响则不明显。研究的结论对今后浅埋大断面单跨洞室暗挖施工方案比选和采用浅埋暗挖洞桩法施工具有指导 作用。

Sensitivity analysis of parameters of cavern-pile method for shallow buried underground excavated tunnels

As current theoretical research on cavern-pile method for shallow buried underground excavated tunnels lags behind application, the three-dimensional model is established with finite element method based on the action-reaction model in design and calculation theory of underground structure. The stability and displacement of surrounding soil masses relevant to different parameters are analyzed by simulating the construction process with cavern-pile method for shallow buried underground excavated tunnels. The results indicate that the stability and displacement of surrounding soil masses are acceptable when the large-section or super-shallow-buried single-span tunnels are excavated with cavern-pile method for shallow buried underground excavated tunnels. The effect of surface subsidence controlling with cavern-pile method for shallow buried underground excavated tunnels is optimal when span is about 14 meters, and almost uniform when embedded depth is different. The displacement of surrounding soil masses is nearly identical for different height of tunnels. The research may be a guide when we choose the most appropriate construction method for shallow-buried large-section single-span tunnels, or constructing with cavern-pile method for shallow buried underground excavated tunnels.