碾压混凝土拱坝诱导缝削弱面积比选取问题研究

为了在各种不可预见性因素的综合作用下碾压混凝土拱坝局部拉应力超标时引导其在诱导缝部位启裂并沿着诱导缝扩展,起到"设缝防裂"和改善应力分布的目的,需要合理选取诱导缝削弱面积比,这对碾压混凝土拱坝分缝防裂设计至关重要。鉴于诱导缝精细化模拟的复杂性,将诱导缝进行概化处理,即采用带开闭迭代功能的接触单元模拟,破坏准则采用"等效强度"判断,基于整坝全过程仿真分析进行了诱导缝削弱面积比选取研究。结果表明:在不同削弱比条件下,坝体主拉应力幅值及分布情况基本相同,诱导缝布置方式即分缝位置对坝体应力改善明显,而缝面削弱面积比对坝体应力变化影响较小。

Study on selection of weakened area ratio of inducing joint for ＲCC arch dam

In order to induce the local racks occurred on some locations of ＲCC arch dam body under the comprehensive effectfrom all kinds of unpredictable factors to be started at the location of inducing joint and developed along inducing joint for gettingthe target of arranging inducing joint for preventing crack and improving the stress distribution therein， the weakened area ratio ofinducing joint is necessary to be reasonably selected， which is quite important for the design of anti-cracking joint. Due to thecomplexity of the refined simulation of the inducing joint， a generalizing processing is made on the inducing joint， i. e. adoptingthe simulation on the contact unit with open-close iterative function and the judgment with the equivalent strength for the failurecriteria， and then the study on the selection of the weakened area ratio of the inducing joint is carried out through the full processsimulation and analysis made on the integral dam. The study result shows that the principal tensile stress amplitude of the dambody is basically coincided with its distribution situation under various weakened ratios， thus the stress situation of the dam bodyis significantly improved by the mode of the arrangement of the inducing joints， i. e. the jointing locations， but the influence fromthe weakened ratio of crack surface is less on the change of the dam body stress.