北京砂卵石地层大直径泥水加压平衡盾构适应性研究

发布时间：2018-05-13 10:52

本文选题：砂卵石地层 + 泥水盾构　；参考：《北京交通大学》2014年博士论文

【摘要】：针对北京砂卵石地层大直径泥水加压平衡盾构适应性这一重要课题,采用颗粒离散元模拟、理论分析、室内试验及现场实测相结合的研究方法,对砂卵石地层中的盾构选型、盾构开挖面失稳破坏特征及影响因素、泥浆特性及其作用、盾构施工对周边环境的影响和盾构刀盘刀具的适应性等关键问题进行了系统研究,取得的主要成果如下： (1)采用PFC2D双轴数值试验及室内土工三轴试验得到了颗粒流细观参数与砂卵石土体宏观参数c、φ的关系,进而通过颗粒离散元模拟分析,揭示了盾构隧道开挖面及地层土体滑移和破坏的渐进性变化特征,描述了土颗粒的位移场演化规律,给出了土颗粒摩擦系数与地层变形之间的动态关系,在此基础上,系统阐述了泥水加压平衡盾构开挖面稳定性的基本原理。 (2)在开挖面上形成良好的泥膜,对于维持开挖面稳定具有重要的作用,其中,泥膜厚度与强度对开挖面稳定影响最大,一定厚度和强度的泥膜是保证开挖面稳定的重要条件。基于泥浆作用原理,通过大量的泥浆试验,提出了适于北京砂卵石地层大直径泥水盾构的泥浆相对密度、粘度等特性参数；从渗透距离、极限渗流量、孔隙水压力以及泥膜抗渗性4个方面对3种类型泥浆的作用效果进行了分析评价,并对其适应性进行了分析。 (3)现场实测数据表明,科学的刀盘刀具配置、合适的泥浆特性参数及合理的掘进参数条件下,泥水盾构对北京砂卵石地层具有良好的适应性,盾构施工引起的地层变形能够满足安全和环境影响控制的要求；基于实测数据和理论分析,建立了盾构掘进参数与地层变形之间的关系,论证了带压进仓换刀的安全性及其对周边环境的影响程度。 (4)为了使大直径泥水盾构对北京砂卵石地层具有更好的适应性,提出了滚刀、撕裂刀、切刀等长短刀具的合理化及立体化配置方案,对致密砂卵石地层的刀盘刀具配置方案进行了专门设计；基于实测数据,比较分析了单刃滚刀与双刃滚刀的平均磨损系数,进而提出了砂卵石地层掘进过程中的刀具更换原则：每100-120m进行一次带压进仓检查并对磨损较大的刀具进行更换,每230-300m设置一个停机加固点进行刀具更换。
[Abstract]:In view of the important subject of large - diameter mud - water pressure balance shield adaptability of sand - gravel stratum in Beijing , this paper studies the selection of shield in the sand - gravel stratum , the characteristics of failure and damage of shield excavation surface and its influence factors , the characteristics of the mud and its function , the influence of shield construction on the surrounding environment and the adaptability of the cutter of shield cutter . The main results are as follows :

( 1 ) Using PFC2D biaxial numerical test and indoor geotechnical triaxial test , the relationship between the meso parameters of particle flow and the macroscopic parameters c and 蠁 of sand and gravel soil is obtained . Through the simulation analysis of the particle discrete elements , the evolution law of the displacement field of the shield tunnel and the formation deformation are revealed , and the dynamic relation between the friction coefficient of the soil particles and the formation deformation is given . On the basis of this , the basic principle of the stability of the excavation face of the shield tunnel is expounded .

( 2 ) A good mud film is formed on the excavation face , which plays an important role in maintaining the stability of the excavation surface . The mud membrane with the largest thickness and strength on the stability of the excavation face is an important condition for ensuring the stability of the excavation surface . Based on the principle of mud action , a lot of mud tests are adopted , and the characteristic parameters such as the relative density , viscosity and the like of the slurry suitable for the large - diameter mud - water shield of the Beijing sand - gravel stratum are proposed ;
The effect of three types of mud is analyzed and evaluated from four aspects of seepage distance , limit seepage quantity , pore water pressure and permeability of mud membrane , and its adaptability is analyzed .

( 3 ) On - site measured data shows that the mud - water shield has good adaptability to the sand - gravel stratum in Beijing under the conditions of cutter - cutter configuration , proper mud characteristic parameters and reasonable tunneling parameters , and the formation deformation caused by shield construction can meet the requirements of safety and environmental impact control ;
Based on the measured data and the theoretical analysis , the relationship between shield tunneling parameters and formation deformation is established , and the safety and the influence on the surrounding environment are demonstrated .

( 4 ) In order to adapt the large - diameter mud - water shield to the sand - gravel stratum of Beijing , this paper puts forward the rationalization and three - dimensional configuration scheme of hob , tearing knife , cutter and so on .
Based on the measured data , the average wear coefficient of single - edge hob and double - edge hob is compared , and the principle of tool replacement in the course of sand - gravel formation is put forward : every 100 - 120m is checked and replaced every 100 - 120m , and the tool is replaced every 230 - 300m .

【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U455.43;U455.39

【参考文献】