Improving the design of the tunneling shield cutting working body

Object of research. The article presents a variant of improving the design of the working body of the tunneling shield, namely, its cutting part. Research aims to confirm the performance of the proposed design using the method of solid 3D modeling in T-Flex CAD. Methodology. The working body of the tunneling shield has been improved by making changes to the design of the working surface of the rotor. Theoretical studies have been carried out to determine the strength characteristics of the proposed rotor design. The proposed rotor model was visualized using the T-Flex CAD software product. The advantages of the solid-state method of 3D modeling are that the mathematical model is endowed with the real physical properties of the object (weight, volume, material, surface area, etc.), and the technology of rapid prototyping allows you to get layouts of photorealistic images in the shortest possible time. Results and discussion. Based on the results of the data obtained in the course of theoretical studies, a comparative analysis of the strength characteristics of the basic and modernized models of the tunneling shield cutting working body was carried out. The studies carried out in T-Flex CAD have confirmed the functionality of the modernized design of the tunneling shield working body. An algorithm for calculating the strength characteristics of the proposed rotor design is presented. The algorithm is universal and can be used to calculate other designs of the tunneling shield working body. Conclusions. As a result of the research carried out, the strength characteristics of the rotor have been determined. Maximum values: displacement modulus – 2.875 · 10–5 m, equivalent stresses – 29.47 MPa, and safety factor for an equivalent stress is 9.446 · 106.

Design Improvement of Cutting Part in Tunneling Shield

The article presents a variant for improving the design of a working body of a tunneling shield, its cutting part to be more precise. The working body of the tunneling shield has been improved with the changes in the design of a rotor working surface. The theoretical studies aimed at determining the strength characteristics of the proposed rotor design have been carried out. The proposed rotor model has been visualized with the use of the T-Flex CAD software. On the basis of the results obtained in the course of the theoretical research, a comparative analysis of the strength characteristics of the main and improved model of the cutting working body of the tunneling shield have been made. The studies carried out at T-Flex CAD confirmed the working capacity of the improved design of the tunneling shield working body. The strength of the rotor has been determined as a result of the studies carried out. The maximum values of the displacement module is 2.875E-05 m, the equivalent stresses are 29.47 MPa, a reserve coefficient on equivalent stresses is 9.446E 06.

Combined Positioning Device for the Control System of the Microtunnel Boring Machine

The issues of developing a combined positioning device for the microtunnel boring machine control system are considered. A device combining laser and inertial methods of determining coordinates is proposed, which provides the possibility of determining the coordinates and spatial position of the tunneling shield during the construction of straight and curved tunnels by the pushing method. A method for connecting the positioning device with the microtunnel boring machine control system based on the RS-485 wired interface is proposed. A method for calculating coordinates has been developed that takes into account the rotation of the local coordinate system relative to the local geodetic coordinate system.

Modeling the Process of Controlling the Microtunnelling Boring Machine's Motion

The problem of determining the control action, the optimal number and combination of hydraulic cylinders required to guide the tunnel shield along the project axis of the tunnel with the required accuracy is consid-ered. An algorithm for the formation of a combination of hydraulic cylinders for moving the shield is applied, creating an effort in accordance with the magnitude of the control action, determined by the deflection of the shield in the vertical and horizontal planes. Analytical expressions for determining the control parameters are given. Modeling the process of controlling the movement of the tunneling shield showed that the proposed method provides the required accuracy of guiding the tunneling shield in accordance with the design direction.

The Cutter Head Drive Theoretical Model of a New Multi Dual-Eccentric Axes Tunneling Shield Driven by Hydraulic Cylinders Directly

Based on work principle analysis of a new multi dual-eccentric axes tunneling shield, the advantages of adapting well to large diameter long distance tunnel and energy saving are showed in detail. Then, the cutter head drive theoretical model driven by a single hydraulic cylinder is analyzed, the expressions of driving force and hydraulic cylinder flow are set up, they all vary with the position changing of the cutter head. On this basis, the multi cylinders drive theoretical model is obtained by superposing the expressions of each cylinder. Subsequently, the relationships between working pressure, system flow and cutter head rotating speed under the working conditions of constant torque, constant flow and constant rotating speed are analyzed. The analysis results show that the working pressure and system flow are fluctuating when the cutter head rotating speed maintains constant, and the cutter head drive system is of constant power, and this is also the actual work condition of the shield. At the same time, each hydraulic cylinder stroke remains determined phase matching relationships. Finally, as the example with five cylinders driving, the matching relationships of the hydraulic cylinder strokes are discussed.

Artificial Ground Freezing for Rehabilitation of Tunneling Shield in Subsea Environment

Artificial ground freezing method was employed in the rehabilitation project of a subsea tunnel. To ensure safety of the subsea rehabilitation work, special design and research were conducted considering the unfavorable influence of the salt in seawater had on freezing effect, such as thickness thinning and strength loss of the frozen wall. A shell-shaped frozen soil wall was designed to cut off the leakage channel into the shield. Double rows of vertical freezing pipes with limited-depth freezing were settled in front of the cutter head, and auxiliary freezing pipes were settled at the sides of the shield to achieve the design goal. Results of analyzing monitoring data on frozen soil temperature showed that the design was reasonable for shield rehabilitation in subsea stratum.

High Pressure Pipeline Project Within a Long and Deep Tunnelling Shield in Urban Area

Installation plan of diametrical pipeline within the existing circular trunk line was officially announced in 2002 as ‘Central Trunk Line’;- gas transmission of 23.1 km length linking from the Tokyo Bay side to the opposite side of the circle. Main feature of this line is that the pipes of 610mm outside diameter, 7MPa MAOP and of Grade 552 (X80) equivalent material is to be installed within a tunneling shield all along the route to avoid unnecessary negotiation with road authorities and adjacent inhabitants. The 2m diameter tunnel will be excavated 40m under ground surface in average, 60m in the deepest. The construction started last autumn and will not be completed until the year 2009. This paper refers to be design concept and outline of the narrow and long tunnelling and piping techniques utilized to reduce the construction costs.