丰满重建工程新坝开挖及混凝土浇筑对老坝稳定、应力的影响分析

Analysis of the influence of new dam excavation and concrete pouring on stability and stress of old dam in Fengman Hydraulic Station Reconstruction Project

丰满重建工程新坝建设期间,老坝仍需正常挡水运行,同时兼作新建工程的上游围堰使用。由于丰满老坝的先天性缺陷导致坝体结构、混凝土强度、防渗等方面仍存在安全隐患,且新建大坝距离老坝较近(120 m),新坝建设期间不同施工阶段及各种因素对原坝的原有运行状态会产生一定影响。针对新坝基坑开挖和混凝土浇筑这两方面的影响,通过有限元法对新坝坝基开挖及坝体浇筑施工的全过程进行数值仿真计算,针对典型河床坝段及岸坡坝段,研究在新坝基坑不同开挖范围和深度情况下,老坝处于不同运行水位时的安全稳定状态,浇筑新坝混凝土时老坝的实时应力和稳定状态,分析评价新建工程对老坝稳定及应力的影响,保证新坝建设期老坝运行安全,进一步研究并完善新建工程开挖方案。

During the construction of the new dam of the Fengman Hydraulic Station Reconstruction Projects,the old dam still needs normal water blocking operation and also serves as an upstream cofferdam for the new project.Due to congenital defects of Fengman old dam,there are still hidden safety hazards in dam body structure,concrete strength,anti-seepage,etc.,and the new dam is close to the old dam(120 m).Different construction stages and various factors during the construction of the new dam,the original operating state of the original dam will have a certain impact.In this paper,for the influencing factors of new dam foundation pit excavation and concrete pouring,the whole process of new dam foundation excavation and dam body pouring construction is numerically simulated by finite element method,for typical river bed dam section and bank slope dam section.To study the safety and stability of the old dam at different operating water levels under different excavation ranges and depths of the new dam’s foundation pit,the real-time stress and stable state of the old dam when pouring new dam concrete,and analyze and evaluate the stability and the influence of stress ensures the operation safety of the old dam during the construction period of the new dam,and further studies and improves the excavation plan of the new project.