Abstract: The design principle and technology feasibility of the final joint are key difficulties for the whole project construction. In order to improve the structural design and construction technology of the pushout final joint, the scale model test research is carried out through the original hydraulic pushout test platform. In the test, parameters such as water injection, slide friction coefficient, and pushout stability were recorded and analyzed,and the stress of key structures is analyzed by finite element method. The results show that: (1) the pushout realizing mechanisms of final joint conforms to Bernoulli equation, and the Reynolds number of the fluid inside the ejection section is controlled below 2 000 to maintain the flow rate in the laminar flow range; (2) the downward deflection angle of the pipe joint in the pushing process is less than 0.1°, and the left and right deviation is 3 mm, the effect of the hydraulic pushing process is good; (3) the stress of the key structure of the pipe under the action of water pressure is safe, the numerical analysis is basically consistent with the measured value of the test, the rationality of the key structural scheme of the final joint is verified, and the launching method is feasible, the friction coefficient of the slide design can be taken as 0.13.

Key words: ShenzhenZhongshan link, immersed tunnel, final joint, hydraulic pushout system, model test