Abstract: To improve the elastic performance and deformation adaptability of seamless expansion joint materials at the joints of the subsea immersed tunnel under different temperature conditions, the representative asphalt and polyurethane seamless expansion joint materials are designed and their deformation properties are examined. According to the cyclic tensile and compressive deformation characteristics of seamless expansion joint materials under actual service conditions, the tensile, tensile recovery, and compression recovery tests are conducted under various temperature conditions, and the tensile, tensile recovery, and compression recovery properties of asphalt and polyurethane seamless expansion joint materials are analyzed. The results reveal the following: (1) The optimum oil to aggregate ratio of the these two kinds of materials is 24%. The oil to aggregate ratio will significantly affect the tensile properties and high temperature performance of asphalt materials, and the gradation has a significant effect on the tensile properties of polyurethane materials. (2) These two types of seamless expansion joint materials have excellent ability to adapt to tensile deformation, and the tensile strength of polyurethane materials is approximately 70% higher than that of asphalt materials. (3) In the temperature range of 20 to 40 ℃, the tensile recovery rate of two kinds of seamless expansion joint materials is more than 70%, and the compression recovery rate is more than 60%, which can meet the requirements of expansion joint of immersed tube tunnel. (4) In the temperature range of 0 to 60 ℃, the performance of asphalt materials is significantly affected by temperature, while polyurethane materials have lower temperature sensitivity.

Key words: immersed tunnel, seamless expansion joint, material design, modified asphalt, polyurethane, deformation performance