为了解决目前公路隧道常规排水系统不足导致隧道运营期间面临水压过大的难题，提出并设计一种新型三向排水系统，在仰拱中心设计单向阀门来进行排水，并设计模型试验组来进行降压性能的验证，同时根据试验规律逆向进行理论推导，探究新型三向排水系统的降压规律以及适用性。所设计的排水系统是一种可“点对点”对隧道进行排水降压的三向排水系统，组成包括常规的纵向、环向排水盲管以及仰拱处设计的单向阀门通道。从模型试验的结果来看，三向排水系统可以有效缓解环向和纵向排水盲管的排水压力，让大部分高水压力从仰拱处的单向阀门排出隧道；三向排水系统的降压能力与数量、管径大小等参数有直接关联，主要表现为数量越多，管径越大降压效果就越明显。同时试验与理论的水压力误差可以控制在约5%。通过试验与理论结合的方式对新型三向排水降压系统的水压力变化规律进行了验证。研究成果可为后续工程提供一定的参考价值。

In order to solve the problem of excessive water pressure during tunnel operation caused by the insufficiency of conventional drainage system in road tunnels, a new three-way drainage system was proposed and designed, with a one-way valve in the center of the elevated arch to carry out drainage, and a model test group was designed to validate the pressure-reducing performance, and a theoretical derivation was carried out according to the experimental law in reverse to investigate the pressure-reducing law of the new three-way drainage system and its applicability. The designed drainage system was a kind of three-way drainage system that can "point-to-point" drain the tunnel to reduce pressure, which consisted of conventional longitudinal and circumferential blind drainage pipes and one-way valve channel designed at the upward arch. From the results of the model test, the three-way drainage system can effectively alleviate the drainage pressure of the annular and longitudinal drainage blind tube, so that most of the high water pressure from the one-way valve at the elevated arch out of the tunnel. Three-way drainage system pressure reduction ability and its quantity, pipe diameter size and other parameters are directly related, mainly manifested in the greater the quantity, the larger the diameter of the pipe, the more pronounced the effect of pressure reduction. At the same time, the water pressure error between test and theory can be controlled at about 5%. The water pressure variation law of the new three-way drainage pressure reduction system was verified through a combination of experiments and theory. The research results can provide certain reference value for subsequent projects.