三峡泄洪坝段孔口配筋方案空间弹塑性分析

采用空间弹塑性有限元法，考虑钢筋和混凝土的联合作用，对三峡泄洪段孔口配筋方案进行了分析研究。确定了设计工况下大坝孔口周围混凝土的开裂范围和钢筋的受力情况。通过逐级加大孔内水压力强度，求得钢筋应力达到屈服时的内水压力超载系数，用以估计孔口配筋后的强度安全度。研究结果表明，对于泄洪坝段的泄洪深孔，当采用典型配筋方案时，在设计荷载的作用下，孔口周围仅在局部区域发生开裂，最大开裂深度约0．5m；在内水压力超载系数为2．8时，孔顶钢筋开始屈服，孔顶混凝土形成数道纵深裂缝，这时孔口达到了极限承载力状态。

Spatial elastoplastic analysis of reinforcing outlets in flood release dam section of TGP

Reinforcement schemes of outlets in flood release dam saction of the Three Gorges Project(TGP) are analysized and studied by using spatial elastoplastic finite element method and taking combined action of reinf orcement and concrete into account.Cracking scope of concrete and stressing stat e of reinforcement in surrounding zones of outlets are determined under the desi gn condition.Through increasing the water pressure in outlets in a step by step way,an overload coefficient of internal water pressure with reinforcement stress reaching its yield stress is determined and used to estimate the strength safet y of the reinforced outlets.Results from analysis show that for deep outlets in the flood release dam section,when the typical reinforcement scheme is selected, cracking occurs only in local zones surrounding outlets under the design load,th e maximum depth of cracks is about 0.5 m;when the overload coefficient of intern al water pressure is 2.8,reinforcement bars in the outlet roof start to yield an d several longitudinal deep cracks are forming in concrete there,and at this tim e,outlets get to their ultimate bearing state.