【作者】 迟朝明；

【导师】 刘树堂；

【作者基本信息】 山东大学 ， 道路与铁道工程， 2013， 硕士

【摘要】 随着我国经济的快速发展,国家对基础设施建设的重视程度日益提高,由于土地资源的逐步紧缺,在很多沿海地区,通过填海造陆,“向海洋要陆地”已经成为一种趋势。在沿海地区修建港口码头、工业民用建筑、机场、铁路、公路,对地基沉降预测的要求也在不断提高。为了确保工程质量以及施工安全,在软土地基施工期间进行沉降观测就显得格外重要。所得沉降观测资料不仅可以用来判断软土地基的稳定性及其变形速率并进而对填筑的施工进度进行必要的控制,而且可进行沉降预测,推算地基最终沉降量,以及计算沉降速率等,确定预压稳定后路面铺筑时间以及验证设计是否正确合理。本文以青岛胶州湾产业基地围海堤工程软土地基处理为工程背景,首先对现场路基沉降、分层沉降、测斜、孔隙水压力等实测数据进行整理分析,得出针对现场地质情况下的地基变形规律,并通过变形规律确定现场施工指标,如堆载预压卸荷时间以及两级加载间隔时间；然后通过FLAC有限元数值模拟计算,由碎石桩处理后的地基变形情况与未经处理的天然地基变形情况做对比,可知碎石桩处理后的地基差异沉降值、侧向变形值相比天然地基减少50%,因此说明,碎石桩显著提升地基承载力的同时,也增加了软土地基的侧向约束,即碎石桩的加固作用主要表现为对地基土体的挤密；其次通过数值模拟计算,对碎石桩的长方形排布以及三角形排布效果做出比较,可以看出针对现场地基情况,碎石桩按长方形排布时,地基变形更加均匀,而三角形排布时,不同断面沉降以及侧向变形值有一定偏差,当上部荷载较大时,有可能出现“错开变形”,对工程安全带来隐患；最后通过双曲线法、三点法、星野法对现场路基最终沉降量进行预测,通过三种方法结果对比,最终确定采用双曲线法预测沉降值998.22mm,由此所得工后沉降值为48.22mm,符合工后沉降标准。更多还原

【Abstract】 With the rapid development of economy in our country, the country’s emphasis on the infrastructure construction level is increasing day by day. Due to the shortage of land resources gradually, in many coastal areas, by reclaiming land from the sea,"from sea to land" has become a trend. In coastal areas, the requirement of foundation settlement prediction before constructing airports, ports, industrial and civil building railway, highway has been improved. In order to ensure engineering quality and construction safety, settlement observation during the construction of soft soil foundation is especially important. The settlement observation data can not only be used to judge the stability of soft soil foundation, it is more important for predicting settlement, calculating the final settlement, post-construction settlement quantity and sedimentation rate, etc. and eventually determining whether the time of paving roadways and the design is correct and reasonable.This article is based on the seawall engineering of the industrial base of Qingdao jiaozhou bay. Firstly, through the analysis of the site measurement data of the roadbed settlement, layered settlement, horizontal displacement and pore water pressure, it obtain the deformation law of foundation according to the geology condition.and then through the deformation law it determines the index of site construction,such as the unloading time of the stack preloading and the time interval between two level loading. Then it uses FLAC finite element software to carry on the numerical simulation, through the comparison of the deformation situation between the untreated natural foundation and the foundation handled by gravel pile, pointing out that the subgrade differential settlement and lateral deformation value of treated subgrade decreases50%than the natural foundation, so that the gravel pile can significantly enhance the bearing capacity and the lateral restraint of soft soil foundation. I. e., the reinforcement function of the gravel pile mainlt show as lateral compaction of foundation soil. Secondly through numerical simulation, make comparison of the effect between rectangular arrangement of gravel pile and triangle configuration, it is obvious that when gravel pile was arranged in rectangular, the shape shift of the foundation can be more uniformity; and when gravel pile was arranged in triangle, different section settlement and the value of the lateral deformation are all inaccurate. And in the second situation, when the upper load is comparatively big, the chance of "stagger deformation" increases, which brings damages to engineering security. Hyperbolic method, three-point method and Hushino method are applied to estimate the ultimate settlement of roadbed at site at last.998.22mm of ultimate settlement estimation by hyperbolic method is decided to be adopted at last, on which the post-construction settlement of48.22mm is calculated, meeting the standard of post-construction settlement.更多还原