Thermal insulation formwork for high arch dam facing water surface in cold area experimental study on joint water stop

Abstract

Aiming at the key technical problem of joint waterstop for prefabricated non-removable formwork of high arch dams, waterstop tests were conducted on two structural forms: waterstop rubber strips and polyurea coating. The influence of different waterstop materials, structural forms and construction techniques on the waterstop performance of the joint of prefabricated concrete components is analyzed. The test result show that when the external water pressure is 1.5 MPa, there is no leakage in the joint with the polyurea coating waterstop structure. When the water pressure is 0.6 MPa, the waterstop structure with rubber strips causes internal water pressure cracking and water leakage at the local coating. Meanwhile, the joint with rubber strips needs to be continuously pressed with 4 MPa to achieve the above waterstop effect. By comparing the waterstop performance, construction convenience and the strictness of requirements for assembly equipment of the two structures, it is recommended to adopt the polyurea coating waterstop structure for the joint waterstop of prefabricated non-removable formwork on the upstream face of high arch dams. This solves the key problem of joint waterstop of prefabricated non-removable formwork of high arch dams, which affects the structural safety and durability, and provides theoretical basis and practical reference for improving the waterstop effect of the joint of prefabricated components.

Keywords

severe cold region / high arch dam / upstream face / prefabricated thermal insulation formwork / joint water stop test