考虑法向初始抗拉强度和切向抗剪强度变化的拱坝横缝模型研究

A study on contraction joint model with normal initial tensile strength and variable tangential shear strength for arch dam

拱坝横缝在灌浆后保证了坝体的整体性,横缝中的灌浆体具有一定抗拉强度,且球形、梯形键槽对切向滑动的约束与横缝张开度相关。本文在B-可微方程组形式的横缝接触模型基础上,针对法向、切向约束条件进行了修正,提出了考虑横缝初始抗拉强度、键槽切向抗剪力与张开度相关的修正接触模型。数值试验表明,该模型能够模拟拉应力通过横缝在坝块之间传递,以及在横缝张开时,键槽仍能提供较大的切向约束力。

The integrity of arch dam can be obtained after the contraction joints are grouted. The mortar in the joints is able to bear the tensile stresses below the tensile strength. Moreover,the constraints of sphere or trapezoidal shear keys in tangential direction will vary with the opening of the joints. In this paper,based on the contact model represented by the B-differential Equations,an updated model is proposed in which the initial tensile strength and relationship between shear strength of shear key and joint opening is taken into consideration. Numerical example shows that the tensile stresses can be transferred between adjacent dam monoliths through joints,and the shear keys can provide large tangential constraints even if the joints open.