Study on the Discharge System of Excavated Soils in a Vertical Shield Machine

目得：为了在地下深处建造空间或隧道，需要一个大直径的竖井来承载挖掘机。通常，在竖井周围的地面上插入大的铁板，用动力铲或其他机器挖掘被铁板包围的内部。然而，这种方法需要长的施工期和高的成本。另一方面，水平盾构已经广泛应用于水平隧道的施工，并且已经实现了自动化操作。因此，如果将水平盾构机自动化技术应用于竖井施工，将大大缩短施工工期，降低施工成本。然而，水平式盾构机与垂直式盾构机最大的区别在于开挖土的排出系统。由于垂直盾构的掘进方向与重力方向一致，提出了一种新的盾构掘进方向采集机构， ...更多信息 因此，本研究的目的是探讨开挖土的收集方法，并提出一种垂直盾构机开挖土的自动排放系统。研究结果：1）使用固定切割器辐条测量射流延伸2）使用示踪颗粒测量射流速度剖面3）观察挖掘土壤行为4）射流和挖掘土壤速度剖面的理论考虑5）实际机器和小比例模型之间相似性的理论考虑6）结果：1）射流长度随流量和刀盘倾角的增大而减小;钻头形状和间隙的影响可以忽略不计。2）研究发现，开挖土体的行为接近于线性，大部分土体是由分散水射流的中心流输送的。3）根据明渠水流的能量方程，从理论上推导了开挖土体的运动方程; 4）对相似性进行了理论上的考虑，研究结果表明，由于刀盘转速不高，刀盘旋转对土体性状的影响很小。少

PURPOSE : In order to construct the space or tunnel in the deep underground, a large diameter vertical shaft is necessary to carry the excavation machines. Usually, large iron boards are penetrated into the ground around the shaft and the inside surrounded by the boards is excavated by power shovels or other machines. However, this method requires a long construction term and much costs. On the other hand, horizontal shield machines have been used widely to construct the horizontal tunnel, and they are already operated automatically. Therefore, if the automation technology of horizontal shield machine is applicable to the construction of a vertical shaft, the construction term and cost will be much reduced. However, the significant difference between the horizontal shield machine and vertical shield machine is the discharge system of the excavated soils. Since the direction of excavation coincides with the one of gravity in the vertical shield machine, a new mechanism to collect the ex … More cavated soils is necessary.Therefore, the purposes of this study are to investigate the collecting method of excavated soils and to propose an automatic discharge system of excavated soils in a vertical shield machine.RESEARCH PLAN :1) Measurement of jet extension by use of a fixed cutter spoke2) Measurement of jet velocity profiles by using tracer particles3) Observation of excavated soil behavior4) Theoretical consideration of the jet and excavated soil velocity profile5) Theoretical consideration of similarity between actual machine and small scale model6) Measurement of jet and excavated soil behavior by use of the small scale modelRESULTS : 1) It was confirmed that the jet extension decreases with increasing the flow rate and cutter spoke inclination. The effect of bit shape and clearance was negligible small.2) It was found that the behavior of excavated soils is nearly linear and most of the soils are transported by the central flows of the dispersed water jets. Therefore, it was confirmed that the central flows of the dispersed water jet are the most significant factor to design the actual machine.3) The equation of motion of excavated soils was theoretically obtained based on the energy equation of open channel flows.4) The theoretical consideration on the similarity was carried out, and the scale of the vertical shield machine model was determined.5) It was found that the effect of rotation of cutter spoke on the behavior of excavated soils was very small because the RPM of the cutter spoke was not high. Less