Through the example of the practical project , the 3 - d simulative calculations of transient temperature and stress fields of the concrete structure are conducted based on the practical construction scheme . study on the mechanism of the concrete cracking is made and the corresponding methods of . crack repairing are also discussed deeply 以实际工程为例，根据实际混凝土浇筑施工方案对混凝土结构中的非稳定温度场、徐变应力场进行了三维仿真计算，对结构上已出现的贯穿裂缝的成因机理作了较深入的分析研究，提出相应的防裂措施和裂缝补救方法。
Owing to multi - lift characteristics of high rcc gravity dams , great efforts of calculative work should be taken for computing 3 - d temperature and stress fields of the dams . a non - homogeneous multi - laminate element model is put forward to reduce the efforts , making 3 - d simulative calculation of high rcc gravity dams realized 由于碾压混凝土坝成层浇筑的施工特点，给大坝三维温度场和徐变应力场全过程仿真计算带来了巨大的计算工作量，特别在高碾压混凝土坝中尤为突出。
Based on the linear creep theory and deformation coordination principle , the calculation method and computing formulas about the inner force redistribution and the stress redistribution are investigated in this thesis , the validity of this method is demonstrated by comparison the calculated results with the tested results 基于线性徐变理论和变形协调原理,本文研究了二次预应力连续梁的徐变内力重分布和徐变应力重分布的计算理论和计算方法,并与试验结果进行比较,以求验证本文方法的可行性。
Based on the simulation model theory of temperature and stress fields presented in this article , a large simulating program for high rccd has been developed , which can numerically simulate all kinds of temperature control measures , including water pipe cooling , heat insulating in winter , reducing place temperature of concrete , spraying water brume , and long interval over - watering surfaces overflowing in flood season . 基于本文提出的温度场和徐变应力场仿真模型理论，编制了高碾压混凝土坝的三维有限元仿真计算程序，在程序中考虑了各种温控措施的数值模拟，包括：水管冷却、冬季保温、降低混凝土的浇筑温度、夏季混凝土表面喷水雾、施工汛期坝顶面过水等。
A time - variant reliability formulation is presented in this paper to account for the effects of fatigue , corrosion and maintenance actions on the first yield reliability of midship section modulus . a probabilistic model for long - term distribution of wave - induced fatigue stress range is established . for the purpose of obtaining the performance of structure that stands random fatigue load , the concept of stress parameter and equivalent stress range are introduced 船舶在由波浪弯矩引起的交变应力作用下，船体构件焊接点处的微小裂纹逐渐扩展；同时，随着船龄的增加，众多结构构件遭受腐蚀的作用；从而使船体梁剖面模数减小，船体梁承载能力衰减，船舶结构的安全性将受到相当大的影响。
In this article , according to heat conduction theory , elastic creep theory and finite element theory , the temperature field and creep stress field in the arch dam during construction and operation are simulated and analyzed by means of three dimensional finite element relocating mesh method , and the distribution law of the temperature field and creep stress field in the arch dam during construction and operation are systematically studied , and according to the construction process of concrete arch dam , the effect of lamination placement , construction interval , elastic modulus change , thermal insulation change , surrounding temperature change , concrete creep and autogenous volume change on thermal stress in the arch dam are also considered 论文根据热传导理论、弹性徐变理论及有限元理论，用三维有限元浮动网格法对拱坝施工期和运行期温度场、徐变应力场进行了全过程仿真分析，较为系统的研究了混凝土拱坝施工期和运行期温度场、徐变应力场的分布规律，在分析中按照混凝土拱坝施工过程，考虑了混凝土分层浇筑、施工间隙时间、弹模变化、绝热温升过程、环境温度的变化、混凝土徐变、自生体积变形等因素对坝体温度应力的影响。
About thermal stress and temperature control of rcc dam in harsh climate region , this paper emphasizes mainly on the following aspects : 1 . research on space - time distribution rules of the temperature and thermal creep stress of rcc gravity dam in harsh climate region ; analyzing the reason of formation and influencing factors of the horizontal cracks at the dam upstream and downstream face 围绕严寒地区碾压混凝土坝的温度应力和温控防裂，本文主要进行了以下几方面研究： ( 1 )结合两座碾压混凝土坝工程实例，研究了严寒地区碾压混凝土重力坝温度及温度徐变应力时空分布规律，分析了大坝上下游面水平裂缝的成因、影响裂缝的主要因素。
Concentrated on the questions of temperature control and crack prevention studies on high rcc gravity dams , simulative calculation theories of temperature and stress fields of high rcc gravity dams are systematically studied in theory and practice , the temperature control of longtan high rcc gravity dam is analyzed and studied in detail 本文围绕高碾压混凝土重力坝的温控防裂问题，从理论和实践上系统地研究了高碾压混凝土重力坝温度场和徐变应力场的仿真计算理论，并对龙滩高碾压混凝土重力坝的温控问题进行了详细的分析和研究。
At the same time , depended on the creep test of double - prestress composite structure which is just being observed , the calculation theory and method of the redistribution of stress of double - prestress composite structure is studied and some helpful reference for design and research of this new - type structure is offered in this thesis 同时本文结合正在观测中的二次预应力组合结构徐变试验，研究了二次预应力组合结构徐变应力重分布的计算理论和计算方法，为二次预应力组合结构这一新型结构的设计和研究提供了一些有益的参考。
