地铁盾构管片接头抗弯刚度模型试验与数值分析

为研究盾构管片接头抗弯刚度力学特性,采用缩尺模型试验与数值模拟的方法对其进行了研究,得到了如下结果:(1)当弯矩值小于拐点值(150 kN·m)时抗弯刚度曲线可近似为一条过原点的直线,当弯矩值超过拐点值(150 kN·m)时抗弯刚度的曲线斜率变化明显,且曲率随着偏心距e的增大而增大;(2)进行了管片纵缝接头精细有限元模拟,数值模拟获取的抗弯刚度与模型试验获取的抗弯刚度趋势一致,但前者比后者大10%~20%。经过分析得到如下结论:(1)管片抗弯刚度的曲线是高度非线性的非单调函数,其斜率较为复杂难以用方程表示;(2)弯矩越大抗弯刚度越小,正弯矩的抗弯刚度绝对值明显大于负弯矩的抗弯刚度绝对值,在偏心距e固定的情况下,随着偏心轴力N的增大,抗弯刚度先增大后减小;(3)本文数值模拟所采用的方法和选用的本构关系可用于指导计算管片结头抗弯刚度。

Model Test on the Bending Stiffness of Metro Shield Segment Joint and Its Numerical Analysis

The model test was carried out to research the bending stiffness of longitudinal segment joint. The following conclusions are obtained: (1) the curve of the bending stiffness of segment joint is a highly nonlinear and non- monotonic functions whose slope is difficult to be expressed. (2) The bigger the bending moment of the longitudinal segment joint, the smaller the bending stiffness. The absolute values of positive bending stiffness are significantly larger than those of negative ones. The bending stiffness increases firstly and then decreases when axial force increases under the condition that the eccentricity remains unchanged. (3) The curve of the bending stiffness can be simplified as a straight line which passes through the original point when the bending stiffness is less than inflection points (150 ). But when it is greater than inflection points (150 ), the curve shows a significant turn point and the curvature of the curve increases. The bending stiffness obtained from the numerical simulation is consistent with that of the model test, but the former is 10%~20% larger than that of the later. Comparing the numerical simulation results and experimental data, it shows that the results of the model test are reliable, and the method and the constitutive relationship in the numerical simulation are feasible.