【作者】 马洪亮；

【导师】 李永刚；

【作者基本信息】 太原理工大学 ， 水工结构工程， 2007， 硕士

【摘要】 随着涵洞结构物在水利、公路交通、市政建设中的广泛使用，其安全运行的重要性日益突出。在此背景下，能否确定这类结构物的安全使用，是工程设计建设的关键。但是由统计资料可知，涵洞在运行期，甚至在施工期间都存在着较严重的破坏情况发生。这也说明我国目前使用的桥涵设计规范有其局限性，我们对涵洞结构物的研究还有待进一步加深和完善。本文在室内模型试验的基础上，分析了涵洞周边土体的作用机理，通过实测得到了回填土体的位移场和涵洞周边土压力分布情况。此外还使用有限元分析软件ANSYS进行了大量数值模拟，研究了各种因素对结构受力的影响情况，得到了一些可指导工程设计与施工的结论和建议。本文的主要内容包括以下几个方面：(1)系统介绍了不同敷设方式下涵洞的受力特点及计算涵洞洞周土压力的几种公式，并对它们进行分析比较，指出了各公式的局限性。从理论上论述了地下结构物整体计算与分层计算的差别；(2)室内模型试验以刚性地基上的刚性涵洞为研究对象，一方面通过观测埋设于土体中的标志在分层填筑的砂性土自重作用下的沉降位移，得到了填土在不同高度时矩形断面和梯形断面下填土的沉降位移等值线图。另一方面通过电测埋设于涵洞附近的压力盒的变形间接获得方形和圆形两种涵洞周边土压力的分布情况以及洞顶垂直土压力系数K_s与填土高度H、沟槽底宽B和开挖坡度m的关系；(3)阐述了采用有限元方法分析涵洞问题的原理、步骤和技术要求，探讨了如何实现施工过程的模拟问题，再借助大型通用有限元分析程序——ANSYS模拟了上述室内模型试验中的各试验方案，所得模拟结果与试验结果比较吻合，从而验证了所建有限元模型的正确性以及参数选取的合理性；(4)在第(3)点内容的基础上将模拟范围进行拓展，通过增加地基单元系统全面地分析了软基涵洞的受力性状，得到了不同边界条件下洞顶垂直土压力系数K_s与地基和填土弹性模量比值E_d／E_t之间的关系，其结果对于工程设计和规范的制定修改具有参考价值。本文的研究方法，尤其是使用有限元方法模拟施工过程部分，是对解决地下工程问题的一次尝试，还有待于进一步完善。所得成果虽然可以作为进行涵洞土压力方面的科学研究和工程设计的一般方法和理论依据，对涵洞工程的地基加固、管道截面优化和减荷措施研究也具有重要的意义，但是还需要实践的检验。更多还原

【Abstract】 As the culvert is widely used in water conservancy, highway traffic and municipal construction, its importance of using security becomes obvious day by day .Under this background, whether or not to make sure the structure been used safely is the key to the design in a project. But from some statistical data, the culverts are destroyed seriously in the running, even the construction period. It is said that the culvert design criterion which used at present has localization. So the study of this structure still needs more deep and perfect.Based on the model experiments, the paper analyzes backfilled soil action mechanism around the culvert. We get the displacement contour and the distribution of soil pressure around the culvert. In addition, the author put up a great deal of numerical simulation by using ANSYS software, studied the effect of each factor and got some conclusions and advices for project design and construction. The main content of this paper includes four points:(1) Firstly, the paper introduces all the characteristics of culvert with different buried types and several calculation formulas for the soil pressure around culvert. Behind comparing these formulas, the paper points out their deficiencies.(2) Secondly, the room model testing take stiff culverts which based on the stiff foundation as study object. One hand, we observe the settlement value of every sign which buried in soil initially, then get the displacement contour of backfilled soil in different height and section. On the other hand, by using electric apparatus we measure the distortion of pressure cells which buried around culvert and calculate the vertical soil pressure coefficient K_s value.Then the connection between soil pressure coefficient K_s and height H of soil,width B of groove bottom, gradient m is studied.(3) Thirdly, how to use FEM in analyzing culvert problem is expatiated in terms of principle, process and technology. Besides, the paper answers the simulation of construction process. All the last scheme of room model experiments are simulated buy using ANSYS software. The results of simulation accord with experiments. So the model of finite element is right, and the choice of parameters is rational.(4) At last, based on the third result the paper develops simulation range. Culvert which based on soft foundation is simulated roundly by adding new elements to open out the properties of culvert under soil load. The results includes quantitative relation between soil pressure coefficient K_s andfoundation-backfilled soil flexibility module ratio E_d/E_t. It is valuable of thisresult to conduct engineering design and establish or modify criterion.In conclusion, the study method used in this paper, especially the part of construction process simulation in FEM, is a sample to settle underground project problems. It is necessary to perfect the method in the future. Although the results have significant action in culvert study, design, foundation reinforcement choosing section optimization and load reduction measures etc., it needs be checked up in practice.更多还原