砂卵石地层盾构机破岩新机理的分析与研究

发布时间：2019-03-06 13:59

【摘要】：随着城市隧道的广泛应用,盾构机己成为隧道挖掘过程中的不可缺少的工具,有关专家已预言,未来全球50%的隧道建设将在中国。然而,在砂卵石地层中施工,是盾构机当前面临的一个重要课题。盾构在砂卵石地层中施工时,刀盘故障频频发生,而且刀具磨损非常严重,这给施工工程造成了不小的经济负担,己占至整个施工工程成本三分之一。此外,在砂卵石地层施工所需的刀盘扭矩与推进力,一直居高不下,如在某盾构工程中盾构最大的推进力达到了34000KN,最大刀盘扭矩接近5100KN·m,致使刀盘过载较为频繁,从而进一步加剧了刀具的磨损。本文针对目前砂卵石地层盾构施工所面临的问题,以砂卵石地层为研究对象,在前人的研究基础之上提出了“铣削——离散——碾压”的破岩新方法,以达到降低刀具磨损,同时减少盾构机在砂卵石地况下能耗的目的。具体研究内容如下：(1)研究了砂卵石的强度特性,如单轴抗压强度、剪切强度、长期抗压强度等。分析了砂卵石地层盾构刀具的破岩机理、破岩力以及刀盘载荷；对刀具磨损、刀盘故障的原因进行了理论研究。(2)针对目前盾构在砂卵石地层中施工中磨损严重的问题,提出了“铣削——离散——碾压”的破岩新方法：在盾构刀盘上安装铣刀,该铣刀先于其他刀具切削岩石,在原始岩石表面铣削出条状相间的沟痕(称之为“离散化”),然后滚刀再碾压开挖面,从而达到了降低盾构机的切削力、刀具的磨损和节约盾构机的掘进能耗的目的,进而提高了盾构机的掘进效率。(3)为实现“铣削——离散——碾压”的破岩新方法,设计了链轮驱动的行星轮机构,以便实现动力的传递。(4)利用ANSYS Workbench模拟仿真离散化岩石表面沟痕的间距、直径与滚刀摩擦力之间的关系,结果表明当离散化岩石表面沟痕的间距为100mm,直径为60mm时,滚刀破岩时所受的摩擦力比在连续的岩石表面情况下降低了77%。(5)利用ANSYS/LS-DYNA,对滚刀破岩过程进行了显式动力分析,并模拟仿真了岩石表面离散化与滚刀破岩力之间的关系,发现滚刀的垂直力与滚动力分别比在连续的岩石表面情况下降低了75%和90%。(6)利用数值模拟结果,分析了岩石表面离散化后,滚刀磨损量和比能耗的降低率,得出的结论是：滚刀比能耗与磨损量比传统破岩方式分别降低了95%和73%。
[Abstract]:With the wide application of urban tunnel shield machine has become an indispensable tool in the process of tunnel excavation. Relevant experts have predicted that 50% of the world tunnel construction will be in China in the future. However, it is an important subject for shield machine to construct in sand-pebble stratum. During the construction of shield in sand-pebble stratum, the cutter head failure occurs frequently, and the tool wear is very serious, which causes a lot of economic burden to the construction project, which accounts for 1/3 of the whole construction project cost. In addition, the cutter head torque and push force required for the construction of sand-gravel stratum have been high all the time. For example, in a shield engineering, the maximum thrust force of shield machine reaches 34000KN, and the maximum torque of cutter head is close to 5100KN 路m, which leads to frequent overload of cutter head. This further aggravates the tool wear. In view of the problems faced by shield construction in sand-pebble stratum at present, this paper takes sand-gravel stratum as the research object, and puts forward a new rock breaking method of "milling-discretization-rolling" on the basis of previous research, in order to reduce tool wear. At the same time, the purpose of reducing the energy consumption of shield machine under the condition of sand and pebble. The main contents are as follows: (1) the strength characteristics of sand-pebble, such as uniaxial compressive strength, shear strength and long-term compressive strength, are studied. The rock-breaking mechanism, rock-breaking force and cutter-head load of shield cutter in sand-pebble formation are analyzed. The causes of tool wear and cutter head failure are studied theoretically. (2) in view of the serious wear and tear problem of shield machine in the construction of sand and pebble stratum at present, the causes of tool wear and cutter head failure are studied theoretically. In this paper, a new method of "milling-discretization-rolling" is put forward: the milling cutter is installed on the shield cutter head, which cuts the rock before other cutters, and the groove marks between strip and phase (called "discretization") are milled on the surface of the original rock, which is called "discretization". Then the hob compacts the cutting surface, thus reducing the cutting force of the shield machine, the wear of the tool and saving the energy consumption of the tunneling of the shield machine. Furthermore, the tunneling efficiency of shield machine is improved. (3) in order to realize the new rock breaking method of "milling-discrete-rolling", a planetary wheel mechanism driven by sprocket wheel is designed. (4) the relationship between the spacing, diameter and the friction of hob is simulated by ANSYS Workbench simulation. The results show that when the spacing of grooves on discrete rock surface is 100mm and the diameter of grooves is 60mm, the results show that the distance between grooves on the surface of discrete rock is 100mm and the diameter of grooves is 60mm. The friction force of hob during rock breaking is 77% lower than that of continuous rock surface. (5) the explicit dynamic analysis of rock breaking process of hob is carried out by using ANSYS/LS-DYNA,. The relationship between rock surface discretization and rock breaking force of hob is simulated and simulated. It is found that the vertical force and hob force of hob are 75% and 90% lower than those of continuous rock surface respectively. (6) using the numerical simulation results, the vertical force and hob force of hob are reduced by 75% and 90% respectively compared with those of continuous rock surface. The reduction rate of hobs wear and specific energy consumption after the discretization of rock surface is analyzed. It is concluded that the specific energy consumption and wear amount of hob are reduced by 95% and 73% respectively compared with the traditional rock breaking method.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.39

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