【作者】 夏世法；

【导师】 张志诚；

【作者基本信息】 河海大学 ， 水工结构工程， 2004， 硕士

【摘要】 大体积混凝土施工期温度场和应力场的分布是业主、设计方及承包商极为感兴趣的问题。因为水泥的水化作用是一个放热的过程，它所产生的热量在冷却过程中可能导致早期混凝土中温度裂缝的出现，这对水工结构的防渗、抗冲及保持结构的整体性是极为不利的。 本文基于三峡工程右岸地下电站引水洞衬砌混凝土施工期监测资料和仿真计算分析，探讨了三峡工程中大洞径、厚衬砌混凝土在当前施工工艺下施工期温度应力的分布规律及影响因素，全文主要进行了以下几个方面的工作： 1．在不稳定温度场泛函基础上，研究了不稳定温度场隐式有限元计算方法空间离散和时间离散过程，得到相应控制方程。 2．编制了不稳定温度场有限元计算程序，并结合仿真技术，研究了大体积混凝土不稳定温度场的仿真计算方法，在推导典型算例解析解的基础上，验证了计算程序的正确性。 3．研究了考虑水管冷却效果的不稳定温度场的迭代算法，给出了确定水管结点、单元信息的沿程搜索技巧。 4．徐变变形递推计算公式是温度徐变应力有限元计算实现的关键所在，本文用指数函数式表示徐变度，在此基础上，对三维空间问题徐变变形进行了研究，推导了任一时段徐变增量的递推计算公式。 5．研究了温度徐变应力有限元计算的方法，并编制了相应的计算程序，通过算例，用国际通用软件ANSYS验证了自编程序的正确性。 6．把现场监测资料和有限元仿真计算有机结合起来，对三峡工程大洞径、厚衬砌混凝土温度应力分布规律和影响因素进行了研究，得出一些对工程有益的结论。更多还原

【Abstract】 About mass concrete structures, owners, designers and contractors are all interested in the temperature and thermal-creep-stress field. As we all know,the hydration of concrete is a radiative process, which might lead to emergence of,cracks in the early age of concrete while the heat cumulated exhales. Thus great disadvantage may be engendered as far as seepage prevention, erode resisting and the whole structure maintaining are concerned.In this paper, basing on the data analysis and stimulating analysis of the concrete liner of the water diversion tunnel of the underground hydropower station in the right bank of the TGP, the distribution and influential factors of the thermal-creep stress of thick concrete liners with big diameters in the TGP are studied. The following several problems have been solved:1. On the basis of functional of the unstable 3D temperature field, the spatial and temporal sepration of the FEM implicit solution are studied, and the control equation of the FEM calculation is derivated.2.The FEM calculating program of the 3D unstable temperature field is developed, and with the emulator technique, the simulating calculation has also been studied. Some examples which have analytic solutions used to validate the program indicate that the program is completely correct.3. The iterative algorithm of the 3D unstable temperature field which takes the effect of water pipe cooling into account has been studied, and some skills about determining the nodes and elements of water pipes are also given.4. The recurrence formula of the creep strain is the key of FEM calculation of creep stress. In this paper the exponential function is usedto figure the creep strain, and the recurrence formula of 3D creep strain at any periond of time is derivated.5. The FEM calculating method of thermal-creep-stress is studied, and the corresponding program has been developed. With the international program of ANSYS , the program is validated as being right.6. The distribution and influential factors of thermal-creep-stress of the thick concrete liners with big diameters during the construction of the TGP are studied by combining the analysis of field monitoring data and the stimulating FEM calculation. Many conclusions which are useful in the practice are given in the end of this paper.更多还原