基于两类横缝接触模型的拱坝非线性动力响应研究

本文基于主、从接触面的接触边界方法，采用限制接触面切向滑移的弹簧单元，模拟切向完全约束的高拱坝横缝在地震动荷载作用下张开、闭合的非线性力学行为，并应用有限元隐式迭代方法求解结构的动力响应。为了适应拱坝计算，文中对基于接触边界的ABAQUS模型进行了功能扩展，包括引入弹簧单元约束切向滑移、嵌入有限元库水附加质量等。通过讨论接触边界与接触单元模型的有限单元格式，比较了两类接触模型的特点。分别采用该模型与基于接触单元法的ADAm88模型模拟某拱坝的动力响应，两者得到了基本一致的规律：结点位移与横缝开度吻合良好，动位移与开度时程反映出相同的动力响应周期，二者都反映出横缝张开引起的拱向拉应力释放和梁向应力的增加。通过计算验证了ABAQUS模型在拱坝动力计算方面的适用性，说明该模型适合作为一个扩展平台嵌入其他的本构、边界模型以全面模拟实际拱坝的动力特性。

A comparison study of nonlinear dynamic responses of arch dams based on two types of contraction joint models

The contact boundary model comprising master and slave surfaces in ABAQUS model is adopted to simulate the opening and closing behaviors of contraction joints in arch dams during earthquake. Several functions have been added to the ABAQUS code including the implementation of spring elements into the joints, constraining the tangential displacements between adjacent dam-blocks, and insertion of FEM reservoir formulation, etc. The nonlinear dynamic response of a typical arch dam is analyzed by using this model and ADAP-88 based on the contact element method respectively. The numerical results of these two models are consistent with each other in terms of the following aspects: crest displacements and joints opening, frequency components of the dam structures, stress envelopment in arch and cantilever direction and the tendencies of stress redistribution caused by the joints opening. It is concluded that ABAQUS code is preferable for computation of arch dams'response accounting for boundary conditions and material properties.