Papers by Keyword: Shield Machine

Abstract: Due to poor bonding of a shield machine main drive leading to seal failure sealing fracture failure occurs, the proposed installation forms of adhesive sealing method is replaced by platen method, and seal material NBR replaced by a fluorine rubber, so that the combination of the housing seal is more reliable, avoiding the fracture caused by discontinuity of local sealing. Construction process increases the injection of three different oils enhancing the sealing effect. Through the application of practical project, no failure appears after sealing transformation.

Abstract: To discover the interaction rules between the cutterhead of shield machine and the soils, the model experiment of shield machine tunneling is performed, and the particle discrete element model of the experiment is built. By adjusting the particle parameters, the simulated cutterhead torque is compatible with the experiment observed results. Then the displacement of soils in the front of the cutterhead, behind the cutterhead, and in the front of the chamber board is obtained. The soils in the front of the cutterhead try to flow into the nearest opening. However, the soils behind the cutterhead move toward the wall of out barrel. The movement of soils in front of the chamber board is in accordance with the rotation direction of the cutterhead.

Abstract: Double-edged hob is commonly used as a tunneling tool when the shield machine works and it is easy to failure due to its insufficient strength in the rock breaking process. In order to solve this problem, the paper used the theory of finite element to do static simulation analysis of the hob. Firstly, the paper generated a three-dimensional model by using the software Pro/E based on a constant cross section double-edged cutter. Then, the maximum stress, maximum strain and their distributions on the double-edged hob could be obtained from static analysis based on the finite element analysis software ABAQUS. Finally, we could get the conclusion that double-edged hob met strength requirements in the test load conditions by comparing the maximum stress and yield strength of hob material. The results of static simulation analysis provided reference to material selection and optimization design of the double-edged hob and cutter head.

Abstract: At first, this paper discusses the unfavorable environment where a tunnel is constructed by shield machine. As a novel solution, GPR is employed to detect some undesirable obstacles or geological conditions to ensure a smooth tunnel construction. After a brief introduction about the implementation of the detecting system, this paper raises the problem about the signal transferring between the antenna and the GPR body, and between the GPR and the control computer, which are far away arranged each other in two different cabins with relative rotating motion and under a very difficult connection condition. Two signal transferring methods, by cable or by wireless, and their advantage and limitations are discussed. This paper then proposes some key mechanical and electrical modifications on the central swivel joint or some other assemblies of the shield machine to meet the requirement for the signal transferring of the GPR. As this GPR system is supposed to be long-term online detecting equipment, this paper provides a dedicatedly designed power supply to replace the original DC power of the GPR.

Abstract: The shield machine is a large complete sets of equipment used for underground tunnel excavation in the city construction,it has been widely used in the tunnel excavation. Cutter is one of the key components of shield machine. Different geological conditions and badly application environment make the cutter stress complex. German Herrenknecht S749 shield cutter as an example, using PRO/E software to establish the three-dimensional model, ANSYS Workbench module establishes the cutter corresponding finite element calculation model, the force characteristics of the cutter in working process were analyzed, obtained the cutter`s stress strain distribution. The research results can provide basic data for the wheel structure design and construction maintenance.

Abstract: The shape and properties of the sliding wedge in the three models, DIN4085, Jancsecz and Anagnostou/Kovari, are systematically explained, based on the simple and applied properties by using the analytic method to calculate the earth pressure in the tunnel project with shield machine. Combining with the Silotheory proposed by Janssen and the Terzaghi formula, the three pre-add models are applied to calculate the earth pressure in the projects of the Westerschelde tunnel in Holland, the Metro Line 1 in Düsseldorf and the Mostoles railway in Spain, in comparison with the actual earth pressure data of shield machine. The suitable using conditions of the three models in different situations as the shield type, the buried depth, the soil type, the water pressure and the part of the face are summarized, in which the water pressure, the friction angle and the cohesion of the soil are taking a crucial role in the value of the support pressure.

Abstract: The response spectrum of the nonlinear vibration isolation system under harmonic excitation is a continuous one when chaos occurs. This feature is utilized to eliminate or reduce the line spectrum in the radiated noise of the marine vessel. A nonlinear feedback controller was designed with the active control synchronization technology, and the projective chaos synchronization (PCS) was realized with different chaotic driving system. Simulation results show that the spectrum can be attenuated greatly through changing the ratio factor.

Abstract: The method to analysis the strength of planetary trains’ carriers of EPB(earth pressure balance) shield machine is presented in this paper. The structure of the shield machine trains is analyzed and the 3-D solid model of the carrier is built with Pro/E. After the load on the carrier has been dealt with, the strength of carrier is calculated by means of finite element method. The results via ANSYS show that the max stress and strain on the carriers are increasing as the increasing load on it. The max stress is lying on the joint point of the carrier and planetary gear shaft because of the bending deformation of the shaft.

Abstract: With the rapid development of urban construction, the shield construction technology has been greatly developed. Shield tunneling method generally adapts to relatively uniform soil, soft rock and sand rock strata, and the shield tunnel construction has been more mature for the homogeneous strata. However, for the soft and hard interbedded strata, how to solve the problems of breaking the hard rock, increasing the tunneling efficiency and reducing the construction costs, are difficult problems in the shield tunnel construction. In this paper, based on a great deal of theoretical analyses and engineering practices, the effective methods of improving the efficiency of tunneling, reducing cutter wearing and decreasing the construction costs in the process of the shield tunneling construction in hard rock and gravel layer are proposed.

Abstract: The hydraulic long-straight pipeline system of the shield machine is to be studied in this paper. Modal parameters of the hydraulic long-straight pipeline whose length is 8m under three kinds of spans (single span, double spans and four spans) were measured and analyzed. Considering the inherent vibration characteristics of the shield machine, we limited the natural frequency of the multi-span long straight pipeline studied within the range of 0~ 200Hz.What the experiment shows is as follows: Firstly, the natural frequency of the hydraulic long-straight pipeline is densely distributed mainly in the low frequency; Secondly, the natural frequencies of vibration in the horizontal plane are slightly higher than those of corresponding orders in the vertical plane, although the difference is little; In addition, by increasing the number of supports, pipeline span can be reduced and the natural frequencies of pipeline can be significantly increased, but this will make the vibration mode change irregularly.