软岩地下洞库施工的水土耦合有限元模拟

为了解决饱和软岩地下洞库开挖稳定数值模拟分析中的2项关键问题：合适的本构模型和超孔隙水压对岩体受力变形的影响,基于软岩的类超固结土性质,将下负荷面理论应用于修正剑桥模型,推导出适用于研究软岩地层开挖数值模拟的简易本构模型,并通过三轴试验结果与数值模拟结果相比较验证新本构模型的适用性；然后通过某一实际软岩地下洞库开挖工程的数值模拟,对比分析水土耦合和水土非耦合方法得到的数值模拟结果与现场实测结果间的符合程度.结果表明,新提出的所需参数较少的简易软岩本构模型能较好地模拟岩体在开挖过程中的受力变形特征,同时发现采用水土耦合算法模拟饱和软岩地下洞室开挖能够很好地模拟实际开挖过程中围岩的受力与变形情况.

Soil-water coupled numerical simulation on undergroundcavern excavation in soft rock grond

Two key issues concerning numerical simulation on underground cavern excavation in saturated soft rock ground should be solved: a proper constitutive model and the influence of exceed pore water pressure on the stress-strain relation of soft rock.In this paper,from the fact that the mechanical behavior of soft rock is similar to that of heavily over-consolidated soil,a new simple constitutive model was developed by introducing the Subloading surface into the modified Cam-Clay model.The new model is verified by comparing the results of triaxial tests and model simulation.And two numerical calculation methods,namely soil-water coupled and soil skeleton only,were used to simulate an underground cave excavation in soft rock ground.Two simulation results were compared with in-situ monitoring results.It turns out that the new simple constitutive model with few parameters showed satisfactory performance on simulating the mechanical behavior of soft rock during excavation,and the soil-water coupled method was more suitable for simulating the underground cavern excavation in saturated soft rock ground.