【作者】 鲁瑞林；

【导师】 张永兴；

【作者基本信息】 重庆大学 ， 岩土工程， 2005， 硕士

【摘要】 随着西部大开发战略的推进,填土高度在20m以上的高路堤及与之相应的高路堤涵洞越来越多,但由于这些高路堤涵洞缺乏合理的竖向土压力计算理论和方法,使部分涵洞在施工或运营过程中出现了不同程度的损害,大大增加了养护维修费用;与此同时,有的高路堤涵洞结构设计则过分保守而导致工程造价的浪费。因此,高路堤涵洞设计的经济性和安全性问题正日益突出。基于高路堤涵洞拱顶竖向土压力计算理论和方法的不合理性,本论文依托重庆市重点工程金渝大道高路堤涵洞项目,通过布设测试元件进行现场测试、各种竖向土压力理论对比计算以及数值模拟分析等方法,研究了涵顶竖向土压力的分布与变化特征。研究结果对高路堤涵洞结构的设计和施工具有重要指导意义。并在此基础上,提出了减少高路堤下涵洞拱顶竖向土压力的有效措施。所做研究工作和得出的成果如下:(1)研究了高路堤涵洞的竖向土压力变化规律。通过现场测试和数值模拟分析表明,当填土高度达到一定值时,涵顶竖向土压力明显小于理论值γH,涵顶竖向土压力与填土高度呈非线性关系。(2)研究了高路堤涵洞的竖向土压力计算方法。通过线性回归分析和各种竖向土压力理论对比计算,指出非线性土压力公式(σ=ξγHm)计算土压力更接近现场实测值,进行涵洞结构设计既经济合理又安全可靠,是目前较合理的涵洞竖向土压力计算方法。(3)研究了高路堤涵洞上方的拱效应。通过现场测试和数值模拟分析表明,当填土达到一定的高度后,高路堤涵洞将在其上部形成“土拱”,该“土拱”具有不稳定的特征,填土增高过程仍有部分竖向土压力传递到涵顶。(4)研究了高路堤涵洞“土拱”的形成机理。通过现场测试和理论分析,涵顶填土沉降量大于两侧沉降量,“土拱”的形成与地基条件、涵洞位置、施工流程等因素关系密切。(5)研究了FLAC程序在高路堤涵洞中的运用。运用FLAC程序分析计算高路堤涵洞的竖向土压力,能较好地反映填土过程、地形条件及涵洞结构物对竖向土压力的影响,其计算结果非常接近现场实测数据。更多还原

【Abstract】 With Chinese western development, there are more and more above 20m high embankments and corresponding culverts. However, because lack of the reasonable vertical earth pressure theory for designing culverts, some of them fail in the period of construction or after completion of work for using smaller size of structure, in some case culverts under high embankments are designed to bear uncertain pressures with over big size and lead to more cost. So the issue of how to design the culvert economically and safely is concerned more and more.Based on the culvert under Jinyu high embankment of Chongqing priority project, the vertical earth pressure distribution and change characteristic are studied in the paper through on-the-spot arrangement of the test components, calculations of different theories, numeric simulation and so on. The research results have instructive to the design and construction of the culvert under high embankment. On the basis of these, the paper put forward the effective method of reducing the vertical earth pressure on the culvert.The fruits and the work of research in the thesis as follow:(1) The variable principle of vertical earth pressures on the culvert beneath high embankment are investigated in the thesis. The results of the test and the numeric simulation show that the vertical earth pressures are obviously lower than theoretical value byσ=γH , the pressures on the top of culvert increase nonlinearly with the variation of height of embankment.(2) The nonlinear theories of vertical earth pressure calculation on the culvert beneath high embankment are investigated in the thesis. The results of regression analyses and Compared the nonlinear theory with other theory of vertical earth pressures indicate the pressures of nonlinear formula withσ=ξγHm are very close to the test, the pressures for designing culvert are more economic and safe, it is the reasonable method for vertical earth pressure calculation at present.(3) The arching action above the culvert under high embankment is investigated in the thesis. The results of test and numeric simulation indicate that the soil arching are formed above the culverts under high embankment, instability is the characteristic of the soil arching, and a part of pressure is still transferred to the top of culvert when the height of fill is increase.更多还原