盾构管片接头模型法向弹簧刚度确定原则研究

本文针对不设传力衬垫的盾构管片接头的罚函数接触算法和节理单元模型中的控制性参数－法向接触刚度和法向弹簧刚度的取值原则问题进行了相关研究,研究表明:法向弹簧刚度取值过小,将导致引入的计算误差过大,同时,取值也不能太大,更不能取为无穷大,以避免引起方程组病态而导致计算结果失真;弹簧类模型所引起的计算误差在理论上不可能完全消除;Lagrange Multiplier接触算法可完全消除弹簧类型模型引入的计算误差,但计算结果与试验结果相差较大;接头承受轴力越小,则Lagrange Multiplier接触算法计算结果与试验结果相差越大。同时,Lagrange Multiplier接触算法不能解释转动刚度与轴力关联现象。

The Determination Principle of Normal Spring Stiffness of Segment Joint Model for the Segmented Tunnel Lining

The normal contact stiffness and the normal spring stiffness are the key material properties of penalty function algorithm and Goodman element model for the segment joint of segmented tunnel lining and for the joint with no packing material, such as plywood, was placed between the segments, the determination principle of normal spring stiffness of the concrete-concrete contact was investigated. It demonstrated that the computation error could not be eliminated thoroughly by the joint element model. The normal spring stiffness of segment joint model must be set up adequately. An attempt to eliminate thoroughly the computation error by increasing infinitely the normal contact (spring) stiffness may result in the invalid outcome. When the Lagrange multiplier contact method is used, the computation error resulted from spring type of model can be eliminated, but the computation result is different greatly from the test data. The less the axial force on the joint, there would be more difference of the computation result of Lagrange multiplier contact method from the test data. And the Lagrange multiplier contact method could not interpret the correlation of rotation stiffness with axial force.