Abstract:
To optimize the design of drainage system in the Jiuwanshan tunnel of Guinan high-speed railway, we used the coupling theory of seepage field and stress field to research the drainage and pressure relief abilities of three kinds of lings with drainage function, namely the novel floor lining of catchment channel, the floor lining of central drainage ditch and the traditional structure of drainage tunnel + invert arch lining. The safety and applicability of the lining structure were comprehensively evaluated from aspects of distribution law of surrounding rock seepage field, drainage and pressure relief capacity of the lining structure and mechanical properties, etc. On this basis, the effect of circular blind pipe spacing on drainage capacity was studied. The results show that under 60 m ground water level, when the distance between the circular blind pipe and the drainage hole is constant, the external water pressure on the floor and arch part of the new type lining is 294 kPa and 158 kPa respectively, comparing with other two types of lings, the relief rate of water pressures are 17.5% and 12.9% higher than the floor lining of the central drainage ditch, and 15.1% and 28.6% higher than the traditional structure, demonstrating that the new type lining can reduce the water pressure at the arch and floor part, meeting the requirements of structural safety. The water pressure is evenly distributed in the new type lining, which can avoid the bias water load on tunnel when a drainage tunnel is applied.