长短桩处理山区高速公路软土地基的影响因素分析

发布时间：2018-04-23 01:22

本文选题：软土地基 + 长短桩复合地基　；参考：《重庆交通大学》2014年硕士论文

【摘要】：随着我国社会经济的迅速发展，人民对于基础设施的要求也日益增高，尤其对于高等级公路的要求。在高速公路的建设中，我们难免遇到软土、膨胀土、冻土等特殊地质问题。而山区高速公路因为软土的特殊分布，复杂多样的软土特点，在处理软土地基方面存在着一定的困难，用已有的软土处理方法处理时往往打不到预期的效果。因此，研究山区高速公路软土特性及处理方法称为了一项重要的课题。本论文依托贵州省交通厅科技项目——贵州山区高速公路软基处理关键技术研究与示范工程，根据项目收集资料，进行分析。从介绍软土特点入手，着重介绍了贵州山区的软土特点及现有的软土路基处理方法。针对贵州山区软土特点，本文选用长短桩复合地基方法来处理其软土地基。本文对于长短桩复合地基进行了详尽的分析。分别从长桩协力和长桩控沉两个角度对其承载力进行了研究，并提出了其安全系数的修正。根据两种不同情况的承载力进一步提出了沉降计算。本文应用PLAXIS有限元软件，对影响长短桩复合地基稳定性的影响因素一一做了分析，得出了以下结论： 1.CFG桩长的变化对长短桩复合地基沉降造成的影响较大，在临界桩长范围内，CFG桩长的增加有利于控制复合地基的沉降。 2.水泥搅拌桩的桩长变化对于长短桩复合地基的沉降影响很小，但是水泥搅拌桩依然可以保证加固区土体具有一定的承载力，因此水泥搅拌桩依然有存在的必要性。 3.桩间距的变化会影响到桩身的附加应力变化。 4.褥垫层厚度在一定范围内增加时，，CFG桩承受的应力会相应减小。综上所述，本文对影响长短桩处理山区高速公路软土地基的影响因素做了详尽的分析，对于贵州山区处理软基方面有一定的现实意义，为指导工作提供依据。
[Abstract]:With the rapid development of our country's social economy, people's demand for infrastructure is increasing, especially for high grade highway. In the highway construction, we inevitably encounter soft soil, expansive soil, frozen soil and other special geological problems. However, due to the special distribution of soft soil and complex and diverse characteristics of soft soil, there are some difficulties in treating soft soil foundation in mountain expressway, and the expected effect is often not achieved when the existing soft soil treatment method is used. Therefore, the study of soft soil characteristics and treatment methods of expressway in mountainous area is an important subject. This paper relies on the key technology research and demonstration project of soft foundation treatment of Guizhou mountain expressway, which is a scientific and technological project of Guizhou Provincial Communications Department. According to the data collected from the project, it is analyzed. Starting with the introduction of the characteristics of soft soil, the paper emphatically introduces the characteristics of soft soil and the existing treatment methods of soft soil subgrade in Guizhou mountainous area. According to the characteristics of soft soil in Guizhou mountainous area, this paper chooses the method of long and short pile composite foundation to treat its soft soil foundation. In this paper, the long-long pile composite foundation is analyzed in detail. The bearing capacity of long pile is studied from the angle of long pile cooperation and long pile control settlement, and the modification of safety factor is put forward. The settlement calculation is further proposed according to the bearing capacity of two different cases. In this paper, the factors influencing the stability of long-long pile composite foundation are analyzed by using PLAXIS finite element software, and the following conclusions are obtained: The variation of 1.CFG pile length has a great influence on the settlement of long-long pile composite foundation, and the increase of pile length in the range of critical pile length is helpful to control the settlement of composite foundation. 2. The change of pile length of cement mixing pile has little influence on the settlement of long-long pile composite foundation, but cement mixing pile can still guarantee the bearing capacity of soil in the strengthened area, so the cement mixing pile still has the necessity to exist. 3. The change of pile spacing will affect the change of additional stress of pile body. 4. When the cushion thickness increases in a certain range, the stress of CFG pile will decrease accordingly. To sum up, this paper makes a detailed analysis of the factors affecting the treatment of soft soil foundation of expressway in mountainous areas with long and short piles, which has a certain practical significance for the treatment of soft foundation in mountainous areas of Guizhou, and provides the basis for guiding work.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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