Experimental Study on Influencing Factors Associated with a New Tunnel Waterproofing for Improved Impermeability

Abstract

Leakage associated with deformation joints seriously affects tunnel structures. Existing tunnel deformation joint waterproofing structures have high construction costs and inconvenient maintenance requirements. This work proposes a new tunnel deformation joint waterproofing structure. Specifically, this structure combines Ω type water stop, an externally attached water stop, and a concrete component. An impermeability test compares standard waterproofed specimens to improved specimens. Under a variety of deformation joint widths, fatigue loading times, and displacement difference, the variation law of the seepage quantity and impermeability pressure values are obtained. The study also examined the ability of the waterproofing membrane and waterproofing coating to improve on standard practices currently used. The seepage quantity test results indicate a positive correlation of displacement difference and fatigue loading times with seepage quantity. The larger the deformation joint width of the specimen, the more the new construction process demonstrated its ability to resist high fatigue loading times and large displacement differences. As the fatigue loading times increase, the impermeability pressure value of both types of specimens decrease; however, the impermeability pressure value of the improved specimen was less affected, which verifies an increased fatigue resistance. Both waterproofing membranes and waterproofing coatings improve the waterproofing ability of the standard specimen, while the impermeability law demonstrated similar results to the standard process specimen. Ultimately, these findings reveal the value of selecting appropriate deformation joint widths under different practical engineering conditions.