Abstract: To address the issue of insufficient waterproofing performance of prefabricated utility tunnel joints due to uneven compression of the sealing gaskets and the lack of effective compression regulation methods, especially for large-section asymmetric tunnels, an experimental study was conducted based on a specific underground utility tunnel project in a new district. The study involved three types of experiments: laboratory compression tests on sealing gaskets, waterproofing tests on sealing gaskets, and on-site compression regulation tests on prefabricated utility tunnels. The experiments compared the compression performance of sealing gaskets with different materials, different constraint forms, and the presence or absence of grooves on the interface. The study also explored the correlation between the interface stress of the sealing gasket and its waterproofing performance and analyzed the degree of uneven compression and regulation strategies for the sealing gaskets. The results showed that in the initial stage of compression, the deformation of the cross-sectional pores of the sealing gasket was dominant, and the compression amount was linearly related to the nominal interface stress. As the pores were compacted, the slope of the curve increased. The presence of lateral constraints from grooves led to a sharp increase in the slope of the curve. It is recommended that the design value of the sealing gasket compression should avoid lateral constraints from grooves. Considering the actual end-face constraint on the sealing gasket, it is advisable to use annular sealing gasket samples for laboratory compression tests to assess their compression performance. The compression performance of the sealing gasket is not sensitive to the hardness index but is significantly affected by the cross-sectional pore size. The joint waterproofing performance conforms to the interface stress waterproofing theory, and the interface stress of 1.5 MPa specified in the current code provides a high safety margin for waterproofing. The stress-controlled tension method can cause uneven compression of the sealing gasket, which may lead to insufficient joint waterproofing performance. The use of synchronous displacement-controlled tension can achieve uniform compression of the sealing gasket for large-section asymmetric prefabricated utility tunnels. After applying a coating layer, the seepage channels formed by the pitted and rough surface of the concrete at the tunnel joint end face can be effectively filled, ensuring that the interface waterproofing performance of the sealing gasket meets the specified requirements. The findings of this study can provide references for the waterproofing design and effective control of prefabricated utility tunnel joints.