外掺MgO混凝土不分横缝快速筑拱坝仿真分析

Simulation analysis of MgO-concrete arch dam without contraction joints

外掺MgO混凝土不分横缝快速筑拱坝是一项新的筑坝技术 ,广东省阳春市长沙拱坝是国内、外全面采用该项技术建成的第一座拱坝。本文采用了一种新的考虑温度历程效应的MgO微膨胀混凝土仿真分析模型 ,根据实际观测资料对长沙坝进行了有限元仿真分析 ,并对坝体运行过程中出现的裂缝成因进行了初步研究 ,同时研究了掺入MgO以后混凝土自生体积膨胀对拱坝应力状态的改善效果。仿真结果表明 ,外掺MgO混凝土可以补偿坝体温度拉应力 ,对这一类中小型拱坝不分横缝 ,简化温控措施 ,通仓连续快速浇筑施工 。

The fast construction of MgO concrete arch dam without contraction joints is a new technique.This technique has been applied for the first time,home and abroad for construction of Changsha arch dam,which was built in Yangchun City of Guangdong Province.In this paper a new gentle expansion model of MgO concrete considering the effects of temperature history is utilized in the simulation analysis of Changsha arch dam according to the field observation data.Moreover,the cause of cracking and the improvement of stress distribution due to expansion of MgO concrete are also studied.The results show that the temperature tensile stresses are cut down considerably when MgO concrete is used,which avoids the necessity of contraction joints,simplifies the temperature control operation and shortens the construction period.