【作者】 刘超；

【导师】 艾长发； 陈建军；

【作者基本信息】 西南交通大学 ， 建筑与土木工程（专业学位）， 2020， 硕士

【摘要】 随着国民经济高速增长,铁路工程建设进入快速发展时期。我国幅员辽阔,软土存在的区域较为广泛,铁路工程建设经常需要采取针对性的地基加固措施。软土的特点一般为含水量高、渗透性低、压缩性高以及固结时间长等。铁路工程的路基在软土上修筑时,常常发生沉降过大和承载力不足等病害,这对铁路工程安全、高效运行具有极大的危害。郑州-徐州高速铁路沿线存在较大范围的软土地区,并且分布深度薄厚不均匀,有不同厚度、地质状况的软土。因此,结合经验,本文提出了三种地基加固模式,分别为管桩、CFG桩、素混凝土桩,采用有限元软件对三种加固方案进行数值模拟,结合现场实测数据,进行了方案比选,并且分别对三种地基加固模式的施工优化措施进行了研究。最后,得出在不同条件下各种桩型的适用性,供类似工程参考和借鉴。本文主要得出了如下结论:(1)在相同条件下,与桩筏结构相比,桩网结构桩承载力发挥比例较低,对于复合地基承载力的设计计算,需考虑上部结构刚度带来的影响。(2)CFG桩桩体材料中加入工业废料粉煤灰,减少了环境污染,达到料废物利用的目的,具有显著的经济效益和社会效益。(3)采用长螺旋挤压入岩钻机施工的素混凝土桩,保证了桩基的施工质量,节约了施工时间,加快了施工进度,减少了人力成本的损耗,并带来了较好的经济效益、社会效益,具有良好的推广前景。(4)CFG桩、素混凝土桩工作效率最高,在工期紧的情况下,优先采用CFG桩、素混凝土桩施工,可大大减少施工时间。而预应力管桩的施工工艺最简单,施工质量最易把控。更多还原

【Abstract】 With the rapid growth of the national economy,railway engineering construction has entered a period of rapid development.China has a vast territory and a relatively wide area of soft soil.So,Railway engineering construction in China often requires targeted foundation reinforcement measures.The characteristics of soft soil are generally high water content,low permeability,high compressibility and long consolidation time.When the subgrade of the railway project is built on soft soil,diseases such as excessive settlement and insufficient bearing capacity often occur,which has great harm to the safe and efficient operation of the railway project.There is a large area of soft soil along the Zhengzhou-Xuzhou high-speed railway,and the distribution depth is thin and uneven,targeting soft soils of different thicknesses and geological conditions.Therefore,combined with experience,this paper proposes three types of foundation reinforcement modes,namely pipe pile,CFG pile and plain concrete pile.The finite element software is used to numerically simulate the three reinforcement schemes,and the field comparison data is used to compare the schemes.And the construction optimization measures of the three foundation strengthening modes were studied respectively.Finally,the applicability of various pile types under different conditions is obtained for reference and reference of similar projects.This article mainly draws the following conclusions:(1)Under the same conditions,the ratio of the bearing capacity of the pile-net structure is lower than the pile-raft structure.For the design calculation of the bearing capacity of the composite foundation,the influence of the rigidity of the superstructure must be considered.(2)The industrial waste fly ash is added to the CFG pile body material,which reduces environmental pollution and achieves the purpose of material waste utilization.It has significant economic and social benefits.(3)The plain concrete piles constructed by long spiral squeezing rock drilling rigs ensure the construction quality of the pile foundation,save the construction time,speed up the construction progress,reduce the loss of labor costs,and bring a better economy Benefits,social benefits,has a good promotion prospects.(4)CFG piles and plain concrete piles have the highest working efficiency.In the case of tight construction period,CFG piles and plain concrete piles are preferred for construction,which can greatly reduce the construction time.The construction technology of prestressed pipe pile is the simplest and the construction quality is the easiest to control.更多还原