沉管隧道节段接头剪力空间分布规律研究

Research on the Spatial Distribution Laws of Shear Force of Immersed Tunnel Segment Joints

为研究沉管隧道节段接头剪力键剪力沿纵向与横向的空间分布规律,文章以地基差异沉降作为试验控制变量,在沉降试验平台上进行了1∶4.69的大比尺沉管节段接头模型试验。同时,在考虑剪力键橡胶垫双线性材料特性及与沉管节段之间、节段与土体之间接触效应的情况下,开展了沉管隧道节段的足尺三维数值模拟。通过模型试验结果与数值模拟结果的对比分析,表明:节段接头剪力键横向剪力分布存在不均衡性,单纯按剪力键榫与剪力键槽接触面积或平均分配接头剪力的设计方法存在一定缺陷;沉管隧道节段接头剪力沿纵向均呈开口向上的二次曲线左半部分的形态进行传递,但随着差异沉降的增大,剪力的衰减速率也在增大;纵向差异沉降时,节段接头剪力影响范围为3个节段;横向差异沉降时,节段接头剪力影响范围为4个节段。相关研究方法与成果可以为沉管隧道接头研究及剪力键设计提供参考与依据。

In order to study the spatial distribution laws of the shear force of shear keys on segment joints along the longitudinal and transverse directions, a 1：4.69 large-scale segment joint model test is conducted on a settlement test platform by taking differential settlement as a control variable. A full-scale 3-D numerical simulation is can＇ied out with consideration to the bilinear material characteristics of shear key rubber blankets and the contact effects between segment joints, as well as segment and soil. A comparison of the model test and numerical simulation results shows that： 1） there is an imbalance in the shear force distributions along the transverse direction, and for the design it is unreasonable to distribute shear force equally or distribute shear force according to the contacting area between the shear key tenon and shear key groove; 2） the shear force of a segment joint is transferred vertically in the form of the left part of a quadratic curve with an upward opening, and the attenuation rate of the shear force increases with an increase of the differential settlement; and 3） the shear force＇s influential scope of the segment joint equals 3 segments for the vertical differential settlement and 4 segments for the longitudinal differential settlement.