A Rapid Trenchless Strengthen and Rehabilitation Method for a Large Diameter GRP Pipe in a Mountain City

Traditional trenchless rehabilitation methods for buried pipelines in plain city are feasible. In mountain city, however, most of the sewage pipelines are setup in the area which is difficult for the large construction equipments to reach. A rapid trenchless strengthen and rehabilitation method for large diameter GRP pipe in mountain city without large construction equipment is proposed in this paper. In the proposed method, the steel casings with strengthen ribs can be made out of the pipe and be constructed through the inspection wells without trench. The location of the casing segment and the size of the strengthen ribs are determined by the numerical simulation of non-linear finite element method. The strength and stiffness of the GRP pipe before and after reinforcement are also compared by numerical analysis. The effectiveness of the present rapid trenchless strength method has been confirmed by the application in the rehabilitation project of the pipelines at West Outlets, New Northern Area in Chongqing.