考虑注浆圈作用的体外排水隧道渗流场解析研究

体外排水方式在隧道工程中已得到逐步应用,但考虑注浆作用的体外排水隧道渗流场解析理论未见报道,导致理论滞后于工程实践。基于镜像法与渗流力学理论,提出了考虑注浆圈作用的体外排水隧道渗流场理论模型,通过解析退化、数值仿真两种方法共同验证了理论模型及解析公式的正确性,探讨了注浆圈渗透系数与厚度对涌水量、隧道外水压力的影响规律。分析结果表明：注浆圈渗透系数对体外排水隧道渗流场存在显著影响,随注浆渗透系数比值增大,涌水量可得到明显控制,但会引起外水压力的增长;注浆圈厚度影响相对较小,其影响主要在于厚度值越大时能一定程度上加强对底部结构外水压力的控制。提出了兼顾隧道限排要求与隧底水压力控制效果的合理注浆圈参数。研究成果以期为体外排水隧道注浆参数设计及施工实践提供参考。

Analytical study on seepage field of tunnels with external drainage considering effect of grouting rings

The external drainage method has been gradually applied in the tunnel engineering, but the analytical theory of the seepage field of the external drainage tunnel considering the grouting effect has not been reported, which leads to that the theory lags behind engineering practice. Based on the mirror image method and the theory of seepage mechanics, the theoretical model of seepage field of the external drainage tunnel considering grouting rings is proposed. The correctness of the formula is verified through the analytical degradation and numerical simulation. The influences of the permeability coefficient and thickness of the grouting rings on the water inflow and the water pressure outside the tunnel are discussed. The analysis results show that the permeability coefficient of grouting rings has a significant influence on the seepage field of external drainage tunnel, and with the increase of the ratio, the water inflow can be controlled obviously, but it will cause the increase of external water pressure. The influences of grouting ring thickness are relatively small, which mainly lies in that the greater the grouting ring thickness, the stronger the control of the bottom external water pressure. The reasonable parameters of grouting rings are put forward considering the requirements of groundwater environmental protection and the control effect of water pressure. The research results may provide reference for the design of grouting parameters and the construction practice of external drainage tunnels.