河水位变化影响下水下隧道的施工力学行为

Mechanical behavior of constructed underwater tunnel Considering influence of river water level fluctuation

针对矿山法施工的下穿河流水下小净距交通隧道,结合数值模拟与现场监测,研究在河水位变化影响下的隧道施工力学行为。首先,考虑河水位变化、隧道开挖面位置变化对围岩的应力场与渗流场的影响,建立三维计算模型,根据现场监测得到的河水位-施工步变化曲线,在模型中设置了92种河水位与施工步的对应状态;然后分析计算结果,并对比数值模拟结果与现场监测结果;最后计算分析河水位暴涨与骤降的8种工况。研究结果表明:在相邻洞施工的影响下,本洞上台阶初衬的最大压应力出现在拱脚;相比前一施工步,施工仅仅向前推进1步的同时如果河水位暴涨5 m,会明显恶化本洞紧邻施工段的初衬的受力状况。基于研究结果提出了若干工程建议。

The mechanical behaviors of underwater river-crossing traffic tunnels with small clearances that were constructed by the mining method were studied from numerical simulation and field monitoring with the influence of river water level fluctuation taken into account. Firstly, the effects of the river water level fluctuation and the excavation face position on the seepage field and stress field of the surrouding rock were considered. The three- dimensional calculation model was established. According to the variation curve of river water level versus con- struction step obtained from field monitoring, 92 cases of construction step versus river water level were fed into the model. Then, the calculation results were analyzed with those from numerical simulation and field monitoring compared. Finally, the 8 cases with sharp rise The results showed that with the disturbance of lining of upper bench of the cave own appeared and sharp fall of river water level were calculated and analyzed. adjacent cave construction, the maximum crushing stress of initial in the arch springing; in comparison with the former construction step, the new construction step that was advanced in conjunction with the sudden river level rise of 5m, could significantly exaggerate the force condition of the initial lining near the construction zone. Based on the research findings , some engineering suggestions were put forward