| 张国新,钮新强,雒翔宇,颜天佑.重力坝加高的应力和稳定计算方法及控制标准研究[J].水利学报,2022,53(4):392-402 |
| 重力坝加高的应力和稳定计算方法及控制标准研究 |
| Study on calculation method and control standard of stress and stability of the gravity dam heightening |
| 投稿时间：2021-11-27 |
| DOI：10.13243/j.cnki.slxb.20211049 |
| 中文关键词: 后帮式 重力坝加高 有限元等效法 新老混凝土结合 |
| 英文关键词: gravity dam heightening thickening back slope finite element simulation bond interface of new and old concrete |
| 基金项目:中国水利水电科学研究院人才托举项目（SS110145B0052021） |
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| 中文摘要: |
| 后帮式重力坝加高存在新老混凝土结合面和新老坝块分载的问题，结合面有限结合部分传力时传统的材料力学法和整体刚体极限平衡法不再适用于应力和稳定计算。本文介绍了重力坝加高模拟的有限单元法，提出了新老坝块应力和稳定计算的有限元等效法，以丹江口7#坝段为例进行了不同结合面状态的多工况计算，与弹塑性有限元强度折减法进行了比较。结果表明：（1）有限元等效内力法可以考虑结合面脱开、新老坝块材料差异、基础非均质性等复杂条件，同时可消除坝踵、新老混凝土结合处的应力集中，具有有限单元法和材料力学法两者的优势，其等效内力计算可通过应力积分法和直接反力法实现，直接反力法得到的等效内力精度更高；（2）采用有限元等效法计算坝基应力和整体及新老坝块局部稳定安全系数时，应力和稳定的控制标准应满足现行规范要求；（3）新老混凝土界面有限结合部分传力时，应力不利工况是贴坡段下部张开，而稳定不利工况是结合面上部张开、下部粘结；（4）丹江口7#坝段斜坡段中下部粘结面积20%以上时应力和温度均满足规范要求，该结论与“后帮有限结合”理论一致；（5）弹塑性有限元法是分析重力坝加高的有效方法，当采用与材料力学及刚体极限平衡法相同的计算模型及屈服准则时，可以得到相同的结果，可采用相同的控制标准，但当采用不同模型及准则时控制标准需要另行研究。 |
| 英文摘要: |
| In the raising of gravity dam by thickening back slope,there are problems of load sharing and interface bonding between new and old dam blocks. When the force is transmitted by partial interface,the traditional material mechanics method and integral rigid body limit equilibrium method are no longer suitable for stress and stability calculation. This paper introduces the finite element method for the simulation of gravity dam heightening, and puts forward the finite element equivalent method for stress and stability calculation of new and old dam blocks. Taking Danjiangkou dam 7# section as an example,the multi-condition calculation of different interface states is carried out, which is compared with the elastic-plastic finite element strength reduction method. The results show that:1) the finite element equivalent internal force method can consider the complex conditions such as separation of interface, material difference between new and old dam blocks,and foundation heterogeneity,and it can eliminate the stress concentration at dam heel and contact point of new and old concrete by the finite element equivalent internal force method. It has the advantages of finite element method and material mechanics method. Its equivalent internal force can be calculated by stress integration and direct reaction force method, The accuracy of equivalent internal force obtained by direct reaction force method is higher; 2) When the finite element equivalent method is used to calculate the dam foundation stress and the safety factor of overall and local stability of new and old dam blocks, the control standard for stress and stability shall meet the requirements of current specifications; 3) When the force is transmitted from the partial interface between new and old concrete, the unfavorable condition of stress is the opening of the lower part of the slope section, while for dam block stability the unfavorable condition is the opening of the upper part and the bonding of the lower part of the interface;4) When the bonding area of the middle and lower parts of the slope section of Danjiangkou 7# dam section is more than 20% of the total,the stress and stability meet the specification requirements. This conclusion is consistent with the theory of "Limited Combination of Interface"; 5) The elastic-plastic finite element method is an effective one to analyze the heightening of gravity dam. When the same calculation model and yield criterion as the material mechanics and rigid body limit equilibrium method are adopted,the same results can be obtained and the same control standard can be adopted. However,when different models and yield criteria are adopted,the control standard needs to be studied separately. |
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