【作者】 徐之青；

【导师】 朱岳明；

【作者基本信息】 河海大学 ， 水工结构工程， 2003， 硕士

【摘要】 本文就水工混凝土裂缝控制问题，从理论上和实践上进行了较深入地研究，解决了实际工程应用中遇到的一些难题，主要工作如下： a．采用了较为先进的仿真技术，编制了可以考虑水管冷却的混凝土结构温度场及徐变应力场三维仿真计算程序，实现了完整模拟碾压混凝土坝分层施工的实际过程的温度及应力的仿真计算。 b．推导了水管冷却混凝土三维温度场严密的计算公式，并提出了水管冷却的子结构解法，算例和工程实例都表明，该方法的计算成果是可靠的、实用的。 c．应用严密的水管冷却的计算方法，对淮河入海水道二河水闸工程进行了温控防裂计算，通过预测混凝土的温度和应力，及时指导施工，并取得了很好的防裂效果。 d．应用“非均质层合单元法”实现了洪口碾压混凝土重力坝施工期、运行期全过程多因素的温度场及徐变应力场的仿真计算，进行多方案的比较分析，推荐出优选温控防裂方案，取得了非常满意的成果。 e．重点讨论了温度场反分析的各种方法，提出应用神经网络法进行参数反分析的算法。 f．研究了寒潮、水管冷却、整浇部分墙体等情况下闸墩表面混凝土应力分布状况。据此对水工墩墙结构混凝土裂缝成因作了较深入的研究，提出了避免类似结构产生裂缝的工程措施。 g．针对温控防裂的一项新技术—外掺MgO混凝土筑坝技术的仿真计算特点，提出了应用“有效时间”理论，来考虑自生体积变形与温度历史有关的膨胀模型，使长期以来困绕工程界有关外掺MgO在任意温度历史下产生的膨胀变形的应力补偿计算成为可能。更多还原

【Abstract】 The crack prevention of hydraulic structures concrete is thoroughly studied from theory and practice in this paper. A lot of practical problems are solved. The main contents are as follows:a. The 3-D simulative calculation program concerning temperature field and creep stress field applying pipe cooling is conducted by adopting more advanced simulation technique. Thereby an effective method is suggested for computing the temperature field and stress field of mass concrete. That method can simulate precisely for RCC(Roller compacted concrete) dam which constructed layered.b. Some precise formulae are deduced for analysis 3-D temperature field of concrete that set many pipes. The basic Sub-structural computation theory of the temperature field of pipe cooling is suggested, some examples and practical projects are given to testify this method be reliable and effective.c. By applying this method, temperature control and crack prevention of concrete of E-he sluice is studied. There are better crack prevention effects for guiding construction timely by forecasting temperature and stress of concrete.d. By applying "None homogeneous multi-laminate element", Hong-kou RCC gravity dam’s simulation computing of temperature field and stress field at construction period and operation period for all courses and many factors.e. Some kinds of methods are discussed in detail for temperature field back analysis, and artificial neural network method for back analysis of thermal parameters of concrete is suggested.f. The stress status of concrete at face of sluice pier in the case of cold wave, pipe cooling and cast-in-place partial sluice pier and so on. And then cracking mechanism of concrete of hydraulic structures such as piers is studied thoroughly, measures of crack prevention in such structures are suggested.g. Temperature control and crack prevention of concrete-the simulation analysischaracteristics of dams construction with MgO concrete, the theory apply "equivalent time" to the model for computing autogenous volumetric change of concrete which be relate to temperature history. It makes computing autogenous volumetric change of concrete be realized at case of arbitrary temperature history, so the problem puzzled engineer over a long period of time may be dispelled.更多还原