超大沉管隧道管节水下顶推精确调整受力运动规律分析

Analysis of the law of the force and motion of the super large immersed tunnel elements during the underwater pushing and precise adjustment

为了解决超大沉管管节在深水条件下线性精确控制的技术难题,并找出管节水下调整时的运动规律,依托港珠澳大桥沉管隧道现场复杂海况的施工条件,通过理论分析建立了内部调整方法的受力模型;并通过解析计算和数值仿真进行了有限位千斤顶和无限位千斤顶情况下沉管顶推过程中运动规律的分析研究,揭示了先铺法沉管水下轴线调整过程受力机理及运动规律。计算得出了沉管初始启动运动力学旋转点位置并进行了验证。实测纠偏沉管尾端偏差为38.3mm时实际实用推力为28800kN,与计算结果偏差仅为240kN,偏差率为8.4%,有效地验证了沉管基床之间摩擦受力的原理与技术参数。

In order to solve the technical problem of linear and precise control of super large immersed tube elements under deep water conditions, and to find out its motion law during underwater adjustment, the underwater sinking and correction method of large-scale components in China are studied. On this basis, relying on the complex sea conditions at the immersed tunnel construction site of Hong Kong-Zhu Hai-Macao Bridge, the force model of the internal adjustment method is established through theoretical analysis. Focusing on the pushing and adjustment process, the motion law of the immersed tube under conditions of the limited place jack and the infinite place jack is analyzed by analytical calculation and numerical simulation. The force mechanism and motion law of the underwater axis adjustment process of the pre-laid immersed tube are revealed, and the movement correction and position adjustment during the precise pushing and adjustment are found in the condition of the 80000 t heavy-duty tube in deep water. The calculation method and verification of the position of mechanical rotational point during the initial starting process of the immersed tube are deeply analyzed. Through application and testing in practical engineering, it is verified that the actual thrust is 28800 kN when the measured deviation in the end of immersed tube is 38.3 mm, which shows only 240 k N deviation from the calculated value and the deviation rate is 8.4%. The research effectively validates the principle and technical parameters of the frictional force between the immersed tube and beds, and provides technical support for precise installation & adjustment and equipment configuration of large immersed tubes under deep water conditions.