考虑地基松弛后的小湾拱坝诱导缝布置分析

Layout analysis of inducing joint in Xiaowan Arch Dam on relaxation foundation

针对小湾拱坝出现地基松弛的实际工程条件,应用三维弹粘塑性有限元方法,分别对两种底部诱导缝布置方案进行对比分析计算,研究不同诱导缝布置方案对拱坝结构的影响,以及坝体内诱导缝面上的力学行为,综合评价在原设计方案基础上结构诱导缝沿左右岸各延伸两个坝段后的效果及其利弊.研究结果表明:两种方案的诱导缝设置高程均是合适的;与基本布置方案相比,诱导缝设置范围扩大后,对拱坝的整体影响并不显著,但对低高程局部部位的影响较明显,低高程部位坝基基岩的抗剪能力削弱明显,有可能影响坝基坝肩防渗体系的可靠性.通过综合考虑,建议采用基本诱导缝布置方案.

On the practical engineering conditions of Xiaowan Arch Dam on the relaxation foundation, the 3-D FEM method is used to analyze the two layout schemes of the bottom induced joint in the dam. By the calculation, the working property of the whole dam and the mechanical behavior of the inducing joint are discussed . The research shows that the elevations of the two layout schemes of inducing joint are suitable; with the case of the extension of the inducing joint is enlarged, the behavior of the whole dam is slightly affected; but the bottom part of the dam is somewhat affected; the shearing resistance capability of the dam base is weakened, so the reliability of the seepage prevention in dam base and dam abutment is very important. It is suggested that the basic layout of the inducing joint is adopted.