考虑诱导缝的碾压混凝土重力坝控裂结构温度场与温度应力数值分析

摘要

同常态混凝土坝一样,碾压混凝土重力坝在施工期仍然存在温度应力问题,较大的温度应力会诱发不可控的温度裂缝,而在坝体中设置诱导缝,可使裂缝在已做好防护措施的诱导缝部位产生,以降低不可控温度裂缝的危害.针对碾压混凝土坝的温度裂缝问题,将诱导缝的优势与新研制的高流动防渗抗裂混凝土(High-fluidity Impermeable and Anti-cracking Concrete,HIAC)材料相结合,根据规范要求制定了设有诱导缝的碾压混凝土重力坝控裂结构方案,建立含有裂缝和HIAC的碾压混凝土坝有限元模型,实现了施工期温度场和应力场的仿真计算与分析.基于计算结果,以坝体上游防渗层施工期的主拉应力为指标,从时间和空间两方面对含诱导缝方案进行评价研究,并对控裂结构诱导缝的布置位置和长度进行了优化,从而得到保障应力释放效果、缝长更短以及施工简便的控裂结构方案.%RCC dams have similar troubles with temperature stress as CVC dams.Stress caused by high temperature will lead to uncontrollable cracks.Induced joints can guide the crack growth to the dam zones with protective measures,and reduce the damage of temperature cracks.Aiming at the problem of temperature cracks in RCC dams,a valid solution has been put forward,considering cracks control structure with induced joints and the prepared High-fluidity Impermeable and Anti-cracking Concrete (HIAC).The FEM model of the studied RCC dam was built with the designed HIAC layer and induced joint,and the numerical simulations of the temperature field and thermal stress were carried through during the construction process.According to the time-space evaluations of the thermal stress near the upstream part of the dam,the initial scheme was optimized with the effective positions and lengths of the induced joints.It could ensure the better effects of stress releasing,reasonable induced joints and convenient construction procedures,and would bring in a better solution to the problem of temperature cracks in RCC dams.