摘要
地基作为承担建筑物重量的载体,其强度与稳定性将直接影响到建筑物的正常使用。为适应黄土地区建设发展的需要,本文以陇西某高速公路黄土地基为研究对象,首先对黄土地基承载力原位试验结果进行分析,然后提出利用强夯法对黄土地基处理并进行承载力试验,最后,利用有限单元法对路堤修筑过程中复合黄土地基的受力和变形特性进行分析。通过该研究可以为黄土地区工程的实践提供技术支撑,其主要工作如下:
(1)利用静力触探、旁压试验、动力触探等原位试验对黄土地基的特理力学性质以及地基的承载力进行试验,并对各方法得到的试验结果进行比较,以确定黄土地区承载力确定的最佳方法。并通过试验确定本场地黄土的湿陷等级,为地基处理提供依据。
(2)对强夯法处理地基的特点和机理进行分析,初步提出采用强夯法处理黄土地基,并利用现场静力触探、旁压试验、动力触探等试验对处理后的复合黄土地基进行承载力试验,并利用试验结果分析强夯法处理效果。
(3)首先对灰土桩和透水桩加固黄土地基的机理进行分析,再对处理后的复合黄土地基承载力进行计算,最后基于Biot固结理论,并结合有限单元法对采用灰土桩和散体材料透水桩加固饱和黄土的变形和固结性状进行分析,并与实测结果进行比较。
通过以上试验和分析,确立了基本方法,得到了黄土地基工程处理的机理和工程参数,为以后的工程地基处理起到一定的借鉴和指导作用。
It is well known that the foundation as the carrier of the construction, so its intensity and stability can affect the normal use of the building directly. However, the relevant theoretical study lags behind the engineering practice. So in this dissertation, the subgrade of certain highway in Longxi was taken as an example. Firstly, the in-situ test was adopted to obtain the bearing capacity of loess foundation for the construction in the loess area. Then, the dynamic consolidation method was obtained to treat the loess. The bearing capacity experiment was executed on the treated subgrade. At last the consolidation deformation of the composite loess foundation was analyzed so as to provide some technical supports for the design of the practice engineering in loess area. The main original work includes:
1. The experiment results of bearing capacity of loess foundation were obtained and analyzed by using many methods in-situ tests such as cone penetration test, pressuremeter test, and dynamic sounding test. The optimum method was ascertained to get the bearing capacity of loess foundation. Further more, the rank of loess collapse was ascertained to provide the foundation of ground treatment.
2. The mechanism of dynamic consolidation method was analyzed firstly, and was used to treat the loess foundation. Then, the cone penetration test, pressuremeter test and dynamic sounding test were adopted to obtain the bearing capacity of the treated loess foundation and their effects were analyzed.
3. Firstly, the treatment mechanisms of lime pile and granular pile were analyzed and the computational method of bearing capacity of the composite loess foundation was presented. Then the theory of consolidation of Biot's and the FEM were utilized to analyze and compare the character of consolidation and deformation of loess foundation treated by the lime pile and granular pile respectively. Further more, the numerical results are compared with the data of measurement.
The mechanism and the engineering parameters of the loess foundation which were obtained through the in-situ test in this dissertation can be used for reference in the future similar ground improvement engineering.
引文
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