真空预压法关键技术研究

发布时间：2018-03-15 18:28

本文选题：软地基处理　切入点：真空预压法　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国基础建设快速发展,在工业民用建筑、市政工程、道路与铁道工程、港口工程等领域常会遇到软地基处理问题。真空预压法具有工程量小、成本较低和对环境影响较小等优点,采用真空预压法处理软地基备受关注。但是传统真空预压法由于存在排水板淤堵等问题,致使其在实际工程中作用效果欠佳。本文采用了资料调研、理论分析、室内试验等手段对真空预压法装置关键技术开展了研究,研究成果对于实际软地基处理有一定的借鉴意义。论文通过文献和工程资料的收集和分析,总结了传统真空预压法的某些不足,如理论研究不够深入,实际工程中出现排水板变形、排水排气通道淤堵、处理区真空度衰减显著、固结效果不佳等。在充分研究了井点井+呼吸井真空预压系统作用机理的基础上,总结了井点井+呼吸井真空预压系统的技术特点,同时利用土体渗透理论和土体固结理论,对井点井+呼吸井真空预压系统装置存在的局部压实、装置淤堵等问题进行了理论分析。提出了通过设置由格栅和砾石组成的防堵滤层和高压气体反冲震荡措施,实现对井点井+呼吸井真空预压系统装置的改进。本文针对井点井防堵滤层设置和气体反冲震荡效果开展了试验研究。通过更换多种滤料和格栅,试验均证明了在井点井外侧设置防堵滤层能起到一定程度的防淤堵作用。由试验找出了可采用的砾石粒径和格栅孔径组合参考范围为1mm～20mm。在此基础上重点研究了滤料粒径、格栅孔径不同组合与排水效率的关系:当采用同一种砾石时,孔径为1mm的格栅排水效率与孔径5mm和10mm的格栅基本一致;当采用同一种格栅时,粒径为20mm的砾石组合初期排水效率最高,粒径为1mm的砾滤层初期排水效率较低,但后期排水效率最佳。综合分析认为滤层采用1mm孔径格栅和1mm粒径的粗砂组合下防止淤堵效果最好。试验还证明了向井点井滤层内间歇性鼓入高压气体,不仅能预防装置淤堵,还能在一定程度打通真空井周围被压实土体,提高排水排气效果。
[Abstract]:With the rapid development of infrastructure in China, soft foundation treatment problems are often encountered in the fields of industrial and civil construction, municipal engineering, road and railway engineering, port engineering, etc. Due to the advantages of low cost and less environmental impact, the application of vacuum preloading to soft foundation treatment has attracted much attention. However, the traditional vacuum preloading method has some problems, such as the blockage of drainage plate, and so on. In this paper, the key technology of vacuum preloading device is studied by means of data investigation, theoretical analysis and laboratory test. The research results have certain reference significance for the actual soft foundation treatment. Through the collection and analysis of the literature and engineering data, the paper summarizes some shortcomings of the traditional vacuum preloading method, such as the theoretical research is not deep enough, In the actual engineering, the drainage plate is deformed, the drainage exhaust passage is blocked, the vacuum degree in the treatment area is attenuated significantly, and the consolidation effect is not good, etc. Based on the study of the mechanism of the vacuum preloading system of the well point well breathing well, the mechanism of the vacuum preloading system of the well point well breathing well is studied. The technical characteristics of vacuum preloading system for well point well breathing well are summarized. At the same time, by using soil permeability theory and soil consolidation theory, the local compaction of vacuum preloading system in well point well breathing well is made. In this paper, the problems of blockage in the device are analyzed theoretically. The anti-blocking filter layer composed of grille and gravel and the backwash oscillation measures of high pressure gas are put forward. The improvement of vacuum preloading system for well point well breathing well is realized in this paper. The experimental study is carried out on the setting of plugging and filtering layer and the effect of gas recoil oscillation in well spot well. By replacing various filter materials and grille, The test results show that the plugging and filtering layer can play a certain role in preventing silting. The suitable reference range of gravel diameter and grid pore size combination is found to be 1mm ~ 20mm. on the basis of this, the filter media particle size is studied emphatically. The relationship between different combinations of grid aperture and drainage efficiency: when the same gravel is used, the drainage efficiency of 1 mm grid is basically the same as that of 5 mm and 10 mm aperture, and when the same grille is used, The initial drainage efficiency of gravel combination with diameter of 20 mm is the highest, and the initial drainage efficiency of gravel filter with diameter of 1 mm is lower. The comprehensive analysis shows that the combination of coarse sand with 1 mm pore diameter and 1 mm diameter is the best to prevent silt blockage. The experiment also proves that intermittent injection of high pressure gas into the filter layer of well point well can not only prevent the device from blockage. It can also improve the drainage and exhaust effect by compacting soil around the vacuum well to a certain extent.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU472.33

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