【作者】 金秋莲；

【导师】 亢景付；

【作者基本信息】 天津大学 ， 结构工程， 2005， 硕士

【摘要】 随着预应力混凝土技术的不断完善和发展,其应用领域和应用范围不断扩大。无粘结钢绞线由于具有预应力摩擦损失小、不需预留孔道和便于施工安装等优点,在一些应力不太大的圆筒形预应力混凝土结构中得到广泛应用,如水池、煤仓、粮仓等。近年来,有些内水压力较大的水工洞室也采用无粘结环锚预应力混凝土衬砌,如引水隧洞、调压室等。这种结构形式在结构布置、预应力分布、施工操作和工程造价等多方面具有明显的优势和发展前景。但目前此种衬砌有限元分析技术方面的经验是不成熟的,有必要进行这方面的研究工作。本文以山西西龙池工程无粘结预应力混凝土衬砌为例,运用有限元方法对此种衬砌进行了计算分析。主要内容如下:(1)无粘结预应力混凝土衬砌三维有限元模型中锚索预应力的分析计算。把锚索预应力当作外力施加到衬砌模型上,并采用荷载分布系数法考虑锚索预应力的不均匀分布特性。此种计算方法,简化了有限元模型,减少了有限元数量,简单地实现了衬砌中锚索预应力的施加。(2)建立无粘结环锚预应力混凝土衬砌三维有限元模型。小浪底工程衬砌有限元计算在施工,检修,运行均采用同一种计算模型。本文通过进一步研究,讨论分析了影响此种结构三维有限元模型建立的诸多因素。提出了建立此种结构模型的新思路。(3)西龙池工程无粘结环锚预应力混凝土衬砌三维有限元计算分析。本文在小朗底工程三种工况(施工,检修,运行)分析的基础上,补充了三维有限元计算结果分析技术,考虑了两种可能在施工中出现的不利情形,保证工程的安全性和经济性。(4)单排锚具槽布置衬砌有限元计算分析。鉴于双排锚具槽布置衬砌的不足之处,本文提出了单排锚具槽布置方案,并对此种衬砌结构的有限元模型进行了分析计算,得到单排锚具槽衬砌的比较优势。更多还原

【Abstract】 The tunnel liner of unbonded circular anchored tendons had been used in modernhydroelectric engineering. It has a lot of advantages over traditional tunnel linermethods such as simpler in installation, more uniform in distribution of the prestress,more economical of the cost and etc. But the experience of using three dimensionsfinite element analysis (3D FEA) method to analyze a tunnel liner is seldom.In coordination with the XiLongChi Project in ShanXi province, this thesis willanalyze the stress distribution of the tunnel liner in details with 3D FEA method. Themain contents are listed as below:(1) The method of how to apply the tensioning force in the tendons in the calculationmodel. The tendons effect is took as the outer loads transferred to the liner model,and the load distribution coefficient is introduced to study the characteristic of theuniform cable prestress. The calculation methods with simple finite element modeland decreased number of the finite element make it easy to the consideration oftendons effect than before.(2) Establishing methods of the FEA model. Several factors are discussed, which is animprovement on the similar analyzing model used ever before. A new method isalso provided to establish the tunnel liner FEM or the parallel structure model.(3) The skills for analyzing the calculation results. Except for the regular calculationitems, two appending conditions were considered in the thesis, one is theoptimizing on the tensioning procedure, another is assuming the break-off of atendon.(4) A new structure with one row of boxouts was proposed and analyzed.更多还原