砂卵石土体流变特性实验装置与实验研究

发布时间：2018-07-07 07:03

本文选题：流变仪 + 搅拌叶片　；参考：《中国地质大学(北京)》2014年硕士论文

【摘要】：砂卵石地层是土压平衡式盾构施工重要施工区域,砂卵石流变性能的研究是土压平衡盾构顺利进行的重要组成部分,如果地层是粘粒含量较少的卵石层、砂土地层和风化岩地层,进入压力舱的土体就很难形成这种“塑性流动状态”,从而给施工带来困难。此时就需要进行土体改良,使开挖土体变成这种状态。而不同搅拌叶片作用下,改良土体流变性能效果就是本文的研究的主要内容。根据实验目的,研制合适的实验装置,以室内实验为主要手段,通过坍落度实验,摩擦系数实验,直剪实验等对不同搅拌叶片对土体改良效果评价,分析得到最优搅拌叶片,并得出改良土体的流变方程。本文主要得到以下几点结论：(1)研制出一个适合实验需要的砂卵石流变仪,并且可以更换多种搅拌叶片。(2)通过实验数据综合分析,得出十字板叶片搅拌效果最佳。(3)对十字板搅拌叶片改良后的土体进行计算分析,推出g,h与屈服应力,塑性粘度的关系式,并推出砂卵石达到塑性流动状态时屈服应力和塑性粘度的大致范围。(4)通过流变仪标定,与商业流变仪ICAR流变仪,进行对比,得出此流变仪数据真实可靠,而且对于6cm以下土体颗粒,均能进行改良,而ICAR流变仪只对2cm以下土体颗粒改良较为有效。本文根据砂卵石土体的特点,研制了改性砂卵石土体流变性测量装置,并对装置进行了标定,获取了不同改良剂添加量下的砂卵石土体流变参数,分析认为改性砂卵石土体属于Bingham流体,用屈服应力和塑性粘度来表征其流变性能,提出了处于“塑性流动状态”砂卵石土体的流变参数范围。
[Abstract]:Sand pebble stratum is an important construction area of soil pressure balanced shield construction. The study of sand pebble rheological property is an important part of soil pressure balance shield tunneling, if the formation is a cobblestone layer with less clay content, In sandy and weathered strata, it is difficult for the soil into the pressure chamber to form this "plastic flow state", which brings difficulties to the construction. At this time, the soil need to be improved, so that the excavation of the soil into this state. The main content of this paper is to improve the rheological properties of soil under the action of different stirring blades. According to the purpose of the experiment, a suitable experimental device was developed. By the main means of indoor experiment, through slump experiment, friction coefficient experiment, direct shear experiment and so on, the effect of different stirring blades on soil improvement was evaluated, and the optimum stirring blade was obtained. The rheological equation of improved soil is obtained. The main conclusions of this paper are as follows: (1) A sand pebble rheometer suitable for the experiment is developed, and a variety of mixing blades can be replaced. (2) through the comprehensive analysis of the experimental data, The results show that the cross blade stirring is the best. (3) the improved soil mass of the cross plate blade is calculated and analyzed, and the relationship between gh and yield stress and plastic viscosity is deduced. And the approximate range of yield stress and plastic viscosity of sand and pebble in plastic flow state is deduced. (4) the rheometer is calibrated and compared with the commercial rheometer ICAR rheometer. It is concluded that the rheometer data are true and reliable. And the soil particles below 6cm can be improved, but ICAR rheometer can only improve the soil particles under 2cm. According to the characteristics of sandy pebble soil, a rheological measurement device for modified sandy pebble soil is developed and calibrated, and the rheological parameters of sandy pebble soil under different modifiers are obtained. It is considered that the modified sand pebble soil belongs to Bingham fluid, and its rheological properties are characterized by yield stress and plastic viscosity, and the rheological parameters range of sand pebble soil in "plastic flow state" is put forward.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU43

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