Project: Optimization Design and Application of Sealing Technology for Precast Urban Utility Tunnel (Box Culvert), by Sichuan Just Rubber Co., Ltd.

The project has optimized the interface form, selection of the sealing material, the waterproof details and the assembly process of the urban utility tunnel (box culvert), which ensured the safety, reliability and durability of the sealing of interface. It has been applied in several projects according to the characteristics of the engineering. The project has been authorized 3 national invention patents and 9 national utility model patents. 

The main innovations of the project are as follows.

I. Developing sealing material with special superior performance for the interface of urban utility tunnel (box culvert), including proportioning the ingredient of the ethylene-propylene-diene (EPDM) rubber and hydrophilic expansion rubber, developing putty compound rubber sealing strip.

II. Optimize the form of the interface of urban utility tunnel (box culvert), using double forms of rubber ring sealing to accomplish multiple fortification which are tested for pressure one by one.

III. Optimizing the waterproof details of the sealing ring, reserving glue (grout) injection passageway to increase the design of remedial measures in the later stage.

IV. Innovatively designing the assembly process, fixing the adhesive strip with the environmentally friendly and quick dry glue before laying the steel mat and dry sand which are tested by pressure one by one.

The sealing technology precast urban utility tunnel (box culvert) interface has been applied and verified in dozens of experimental sections in national projects. The optimization design and application of the sealing technology of the project laid a certain foundation for the fast growing precast urban utility tunnel engineering, made reference for design engineers and provided guidance for manufacture enterprises of precast urban utility tunnel (box culvert) on interface. This project has laid a solid foundation for the popularization and application of prefabricated technology.