开槽预应力闸墩应力集中特性研究

【作者】 王志良；

【导师】 张立翔；

【作者基本信息】 昆明理工大学 ， 工程力学， 2006， 硕士

【摘要】 预应力闸墩作为大型弧型闸门的支承结构，在水利工程中得到了广泛应用。然而，当前预应力闸墩普遍拉锚系数偏大，结构形式不尽合理，在锚索预应力及巨大弧门推力的共同作用下，闸墩锚块内应力状态复杂且应力值大，为了使锚块内部的应力得以释放，设计上通常采用在锚块内开设预留槽的结构形式。在应力水平较高的区域开槽势必会引起槽体形状突变部位的应力集中，因此合理选择开槽的位置、槽的大小以及几何形状等对缓减应力集中就显得非常重要。本论文结合实际工程，针对开设预留槽对锚块内应力分布的影响这一问题展开研究，具体工作有以下几个方面：(1)研究了求解有限域的孔口应力集中问题。把弹性力学中求解孔口应力问题的复变函数理论和边界配点最小二乘法相结合，推导了用于计算预应力闸墩槽孔应力的复变函数法的理论公式，并编制了相应的MATLAB程序，通过算例证明了该方法的正确性和求解的有效性。(2)用本文得到的计算复变函数法对含矩形孔的有限板的孔口周围的应力分布进行了计算，分析了孔口应力集中现象与孔口几何型体的关系，得出了孔口应力峰值的变化规律及发生的位置。(3)用大型工程分析系统ANSYS对某大型水电站的预应力闸墩进行了三维非线性有限元分析，研究了多种开槽方案的应力分布及锚索布置，并得出了供工程应用的最佳开槽方案。(4)通过分析得知，闸墩因开槽而引起应力集中可以被充分的利用，不仅可以提高闸墩的预压应力值，降低拉锚系数，还可以通过改善预压应力的传力路径，使预应力传到更为有效的部位，有效抑制闸墩中出现有害的拉性应力，改善闸墩的应力状态。更多还原

【Abstract】 As a supported structure for a large-scale arch gate, a pre-stressed pier has been widely applied to hydraulic engineering. For the conventional applications in real engineering, the problems of a large tension-anchor coefficient lead commonly to an impropriety structure for the pier. In the conjunction of the rope anchored pre-stress and the hydro push force from the arch gate, a high stresses and complex stress state are often created in the anchor block. A method to solve the problem is to build a rectangular opening in order to release the high stresses in the anchor block and to improve the stress state of the pier. However, a rectangular opening in the highly stressed anchor block will naturally cause stress concentration around the rectangular opening. Therefore, a suitable choice of the rectangular opening position, size and geometrical configuration is to become very important to the design of a pre-stressed pier. This thesis studied the problems of stress concentration due to a rectangular opening in the anchor block of the pier. The tasks done are as follows:1. A complex function method based on the least square method is used to analyze the stress concentration around an opening in the finite domain, and the theoretical formulae of the computational complex function method (CCFM) are established. A computing program has been written in the Matlab language for a rectangular opening and lots of calculations have been done. The results show that the analysis method suggested in this thesis is effective for analyzing stress concentration in a pre-stressed pier.2. The stress around a rectangular opening in the finite domain has been computed with CCFM, the phenomenon of stress concentration was analyzed, and the distribution change law of the stress as the opening configuration and size was obtained.3. A pre-stressed pier of a large-scale hydro power project was studied by using a FEM software — ANSYS and CCFM. Comparisons of many projects of the opening positions and configurations were done. A suitable opening project was obtained and used in the engineering.4. The results of the study show that a suitable setting of a rectangular opening in the anchor block can have a good utilization of the stress concentration in the anchor block and get to an objective to improve the stress state in the pier.更多还原