公路隧道隧底结构水害机理研究

Research on the Water Damage Mechanism of the Bottom Structure of Highway Tunnel

针对目前普遍存在的隧道路面渗漏水现象,基于多孔介质理论,通过建立隧底结构FLAC3D流固耦合数值计算模型,分析了隧底结构形式、孔隙率在交通荷载作用下的动水压力响应特征。研究结果表明:动水压力长消存在一定的规律性,负动孔隙水压力形成的泵吸作用是隧底结构水害发生的根本原因。隧底采用仰拱结构能够有效降低动水压力峰值,大幅降低负动孔隙水压力(泵吸力);无仰拱模式下,孔隙率是影响动水压力的一个重要因素,动孔隙水压力随着孔隙率的增加而增大;车辆荷载对隧底水害发生的影响较大,且超载引起的动水压力峰值最为显著,是造成公路隧底水损坏的主要荷载来源。

For the prevailing water leakage of tunnel road surface,based on the theory of porous media,a FLAC3 D fluid-solid coupling numerical model was built for the bottom structure of tunnel. The hydrodynamic pressure response characteristics of different tunnel bottom structure forms and porosity under traffic load are analyzed. The results show that: the generation and dissipation of hydrodynamic pressure have certain regularity,and the pumping action by negative dynamic pore water pressure is the fundamental reason for the water damage of the bottom structure.Invert structure for bottom structure can effectively reduce the hydrodynamic pressure peaks,and it can significantly reduce the negative dynamic pore water pressure( pump suction); Without invert structure,the porosity is an important factor influencing the hydrodynamic pressure,and dynamic pore water pressure increases as porosity increases; Vehicle load has a relatively greater impact on the water damage for the bottom structure of tunnel,and hydrodynamic pressure peaks caused by overloading are most significant. Vehicle overloading is the main source of water damage to the bottom of the highway tunnel structure.