水电站框格重力坝应力及稳定分析

Stress and stability analysis of sash gravity dam for a hydropower station

为研究广西拉浪水电站扩建工程破坝开孔对坝体稳定性的影响,运用了规范规定的材料力学法并结合三维有限元软件,对4个施工步骤共7种工况下进水口及整个坝体应力及稳定性进行分析,结果表明:材料力学法计算的孔口底部截面最大压应力为0.67MPa,最小压应力为0.34MPa,坝基截面最大压应力为0.63MPa,最小压应力为0.06MPa,均满足《混凝土重力坝设计规范SL319-2005》中坝体上游面的垂直应力不出现拉应力且不大于混凝土允许压应力的要求。进水口以上坝体抗滑稳定安全系数K为1.24,K′为5.28,全坝体抗滑稳定安全系数K为1.10,K′为3.10,均大于《混凝土重力坝设计规范SL319-2005》规定的K为1.0与K′为2.5,满足抗滑稳定要求。在孔口周围、压力管上弯段及下弯段存在局部拉应力区,建议在局部拉应力区合理配筋。

In order to study the stability of the gravity dam for Lalang hydropower station in Guangxi after an intake hole digged in the extension project, material mechanics method and 3D finite element method are adopted to analyze stress and stability under four construction steps in seven conditions. The result indicates that maximum compressive stress of bottom section for intake hole is 0.67 MPa and the minimum one is 0.34 MPa through material mechanics method. And these two stresses of the whole dam are 0.63 MPa and 0.06 MPa. All of these stresses are less than the ones allowed in criterion （SL319-2005）. The stability safety coefficients K and K＇of the dam body above the intake hole are 1.24 and 5.28. The ones of the whole dam are 1.10 and 3.10. All of these coefficients are larger than the ones allowed in criterion （SL319-2005）. There are some tensile stress fields around the intake hole; upper curved section and lower curved section of the pressure tube. It is suggested that these areas should be reinforced with steel bars.