基于预应力实测资料的闸墩结构安全评估研究

针对闸墩中孔周边区域应力分布复杂的问题,进行三维有限元分析。为准确评估中孔闸墩结构运行期的安全性,根据整体拱坝模型计算结果,运用子模型方法,获取各种工况下中孔闸墩结构的局部边界条件,基于锚索测力计实测数据,建立考虑时效、外界温度及上游水位波动等影响的预应力回归模型。在此基础上,采用三维非线性有限元分析方法对西南某碾压混凝土拱坝中孔闸墩结构进行全面安全评价。计算结果表明:当前工作状态下,闸墩结构应力分布规律与设计状态基本相同,颈部最大法向应力为1.27 MPa,出现在左中孔右边墙位置,小于允许拉应力1.54 MPa,满足闸墩抗裂要求。

Measured prestress data-based study on safety assessment on gate pier structure

In order to accurately evaluate the safety of the gate pier structure of the mid-level outlet during operation period，consideration of calculation precision and effciency,the local boundary conditions of the gate pier structure of the mid-level outlet under various working conditions are obtained herein with the sub-model method according to the calculation result of a whole arch dam model，and then a prestress regression model is established under the consideration of influences from time-effect，external temperature，fluctuation of the upstream water level，etc. On the basis mentioned above，an overall safety assessment on the gate pier structure of the mid-level outlet for a RCC arch dam in the Southwest China is made with the 3-D nonlinear finite element analysis method. The result shows that the stress distribution law of the gate pier structure is basically the same with its design state，the maximum normal stress at the neck is 1.27 MPa and occurs at the right side-wall of the left mid-level outlet，which is less than the allowable tensile stress of 1.54 MPa，thus meets the requirement of crack resistance for the gate pier.