【作者】 林龙；

【导师】 曹喜仁；

【作者基本信息】 湖南大学 ， 岩土工程， 2008， 硕士

【摘要】 湖南省境内的衡阳至炎陵高速公路项目衡东路段土体大部分属于强风化花岗岩产物,该类土主要由砂粒和粉粒组成,粘性成分缺乏,压实性能差;且由于湖南省地处南方湿热地区,土体天然含水量大,造成其路堤碾压成型困难。目前国内外对粉土和风积砂的压实方法研究较多,而对粉砂土的压实方法和压实特性研究较少。因而系统地研究湖南省境内粉砂土的压实特性,制定适宜的粉砂土路堤压实控制标准,保证路堤的强度、稳定性和耐久性,研究粉砂土在高含水量下的CBR强度特性,总结超湿条件下粉砂土碾压适宜的振动压实参数,最大限度地挖掘其压实度,尽可能地节约土体改良费用,具有较为重要的实际工程意义。本文通过对衡炎高速公路粉砂土路段典型的土体进行室内的压实性能研究,以及对某段粉砂土路堤的现场碾压实验研究,总结出现场碾压适宜的振动压实参数,深化对粉砂土振动压实机理的认识,为粉砂土地区公路设计和施工控制提供理论依据和技术支持。具体地说,得到了以下有益研究成果:(1)研究了粉砂土在潮湿环境下的击实、CBR特性,提出了潮湿粉砂土的压实控制标准,扩充了规范中对潮湿细粒土压实控制标准的适用范围。(2)引入均匀设计理论对公路路堤碾压方案进行了设计,较好地解决了多因素下实验方案的设计问题。(3)总结了潮湿环境下粉砂土适宜的碾压工艺,较好地解决了粉砂土路堤碾压成型困难的问题。(4)在总结分析已有的压实理论基础上,研究了振动对压实土体的作用效应;结合粉砂土的工程特性,深化了对粉砂土的压实机理的认识,并对粉砂土路堤碾压过程进行了分析。(5)在探讨粉砂土路堤沉降机理的基础上,建立了以预测有效度为优化精度指标的多目标组合模型对粉砂土路堤进行沉降预测,提高了沉降预测的精度。更多还原

【Abstract】 Most soil of the Hengyang-Yanlin highway in Hengdong of Hunan province are part of granite’s offspring under the efflorescence, this kind of soil is composed of sand grains and silts, but is short of clay, has the poor compaction properties; simultaneously, as Hunan province is in the south’s moist heat regions, the soil contains much water what makes the embankment to moulding. At the present time, there are many researches about compaction methods of silt and wind blown sand in and abroad, but be shortage of the silty soil. So those are important to seek for the compaction properties of silty soil in the Hunan province, to draw up the suited compaction standard of silty soil embankment for intensity, rigidity stability and wear of the embankment, to research CBR properties of silty soil what is full of water and to summarize its suitable vibrating compaction parameters and roller compaction technics of silty soil what is full of water in Hunan province, to try to exert all it’s compactness for saving soil’s mending cost.This paper searches the compaction properties of the silty soil, and summarizes the suitable vibrating compaction parameters and recognizes the compaction mechanism of embankment deeply to support the theory basis and technique backing for the road design and construction control in the silty soil region. Concretely, this paper has following search profits:(1)The paper searches the compaction properties and the CBR properties of silty soil full of water, proposes the compaction control of the moist silty soil and expands the pratical scope of the moist fine-grained soils compaction control in the standard.(2)The paper leads the uniform design to arrange compaction plan of the embankment compaction, and solves the design problem of several factors test.(3)The paper draws up the suitable compaction technics of silty soil full of water, and solves the compaction difficulty of the silty soil embankment.(4)The paper searches the influence of vibrating to the soil on the basis of summarizing the founded compaction theories, and recognizes the vibrating compaction properties deeply combining with the silty soil’s properties.(5)The paper builds up the combination models with the several targets model of the accuracy norm of the forecasting effective measure to forecast the settlement of the silty soil embankment to enhance the forcasting precision on the basis of searching the settlement forecasting of the silty soil embankment.更多还原