江苏润扬长江公路大桥北锚锭基础围护结构设计优化

【作者】 郭竞宇；

【导师】 董孝壁； 严明； 赵其华；

【作者基本信息】 成都理工大学 ， 岩土工程， 2003， 硕士

【摘要】 润扬长江公路大桥是江苏省“四纵四横四联”的公路主骨架和跨长江通道的重要组成部分；是一座设计车速为100km／h的六车道高速公路特大桥。北锚锭深大基坑位于江苏镇江世业洲尾部下新滩，为南汊悬索桥的重要组成部分．该基础工程不论在开挖深度还是规模上都很具有代表性。作者在现场调研的基础上，探讨了基坑支护结构设计优化问题。主要研究内容可以归纳为：应用基于m法的弹性地基梁杆系有限元方法；在围护结构整体稳定性安全系数与可靠性破坏概率两种控制因素下，编写了嵌岩深度优化的MATLAB程序与围护结构整体设计优化的ANSYS批处理程序；进行了地层抗力比例系数反算、地下连续墙嵌岩深度优化与地下连续墙结构体系整体设计优化。 研究结果表明： (1)对基坑围护结构—地下连续墙的实测土压力和实测侧向水平位移统计分析得出：土压力是一个随开挖深度不断变化的量；在开挖至设计开挖深度的1／2～5／8时，土压力达到最大值。从总体上看，实测土压力小于按传统方法(水土分算法、水土合算法)计算得到的主动土压力。地下连续墙的侧向水平位移是随开挖加深而不断增加的。在基坑开挖过程中，下一道土体开挖对上一道支撑的内力和位移有明显的影响，揭示了经典法(假想梁法、山肩帮男法)的不合理性． (2)基于现场实测主动土压力与实测侧向水平位移下，对锚锭基础范围内的土层抗力比例系数进行反算，结果显示：反算得到的土层抗力比例系数小于按照规范与经验取值。 (3)地下连续墙嵌岩深度优化结果表明：地下连续墙侧向水平位移并非随嵌岩深度的增加而无限制地减小，因此合理的嵌岩深度，既是一个安全问题，也是一个经济问题。 (4)地下连续墙结构体系设计优化结果表明：在不增加内支撑刚度及其截面积的情况下，优化后地下连续墙造价可以减少5.5％左右，内支撑的造价可减少6.3％． 本文结果对地下连续墙设计优化具有一定的参考价值和实际意义。更多还原

【Abstract】 Runyang Changjiang highway bridge is a main bridge of across Changjiang in Jiangshu province, with six lances for 100km per hour designing vehicle speed. It’s deep-large rivet foundation at the north embankment ,in Shiye, Zhenjiang.is a important part of the suspension bridge. The foundation engineering is typical in both excavation depth and scale, on the basis of in-situ investigation, the design optimistic of retaining wall was discussioned in this paper, the mian reseaches including:the using of FEM optimazition methods of rods system;the delvopment of programs for optimazition of imbedding depth of structure based on MATLAB and for whole design optimaziton of the retaining structures based on ANSYS,under the two controlling factors of the saft coefficient and the reliability probability about the whole damage of retaining atructure;the analysis on the m index of soil,the depth of retaining structures imbedded in the rock and the overall optimistic design of retaining structures.The results of research show that:1.The statistical analysis of the in-situ measured soil and water pressures and lateral horizontal displacement of the underground consecution wall revealed that soil and water pressures chang continuously with the excavation depth,the maximum values appear when excavation depth reach 1/2-5/8 of the designing excavation depth.Generally, the soil and water pressures on the underground consecution wall are less than that calculated by conditional ways.The lateral horizontal displancement of the underground consecution wall increase with the increase of excavation depth.during the process of excavation,the following excavation of soil have an obvious effect on inner force and displacement of the previous struts,which proved that classic methods(imagine beam method etc) are unreasonable.2.On the basis of the soil and water pressure and the lateral horizontal displacement in-situ investigation the force-resisting coefficient of soil layers are back-calculated.and it is less than that determinged form standard codes and the empirical values.3.The results of the optimization reseach on the imbedded depth of underground consecution wall show that the lateral horizontal displacment of the underground consecution wall do not infinitely decrease with the increase of the imbedded depth of the underground consecution wll.4.Theresultsof the optimization reseach on the design of the underground consecution wall show that without the increasing of the rigidity and section of struts.the cost of underground consecution wall can decrease about 5.5% or so,the cost of istruts decrease about 6.3%.The results drawed in this paper offering some actual prefencesses.更多还原