Papers by Keyword: TBM

Abstract: To realize accurate prediction of disk cutter performance and determine the crucial parameters in the design process of TBM (Full face tunneling boring machine), a new performance forecasting method of the circular blade cutter is presented, which integrates the parameters of breaking rock such as rock, disc cutter and construction. Furthermore, the second derivation in the process of breaking rock is considered, a new comprehensive performance forecasting model of the circular blade cutter is established based on the Coulomb-Mohr failure criterion. On the basis, the existed performance forecasting models of disc cutter such as Liner Cutting and CSM, and the performance forecasting model of disc cutter presented this paper are analyzed and calculated, according to Colorado linear cutting experiment. The calculation results indicate the prediction accuracy of the performance forecasting model presented in this paper is greatly improved, comparing with the existed models (such as CSM, linear cutting). Finally, the influences of the parameters (rock, disc cutter and construction) are analyzed, which provides for the overall design of TBM cutter and construction with some scientific basis.

Abstract: In order to improve working efficiency of the tunneling process and extend working life of disc cutter, explore the impact of cutter spacing and loading for the cutter rock-breaking effect. With the theory of rock crushing, Based on the finite element analysis software ABAQUS, the process of disc cutter breaking rock is simulated, considering the adjacent cutters sequential constraints, then, to make sure two cutter space with the method of SE in experiment.The simulation results showed that the optimal cutter spacings were both about 80mm in the same loading and the sequentially loading, but the rock-breaking effect of sequentially loading is better than the same loading. The experimental data showed that the minimum specific energy of rock breaking is appeared cutter spacing between 80mm and 90mm. Thus, the correctness and rationality of the simulation was verified. The study is good for understanding the rock-breaking mechanism of double disc cutter and has a certain promoting value to optimize TBM cutter system.Keywords:TBM, rock fragmentation, ABAQUS, cutter spacing, sequentially cutting

Abstract: The current paper first analyzed the degradation mechanisms of the worn disc cutter made of forged H13 chromium alloy for hard rock tunneling applications. The paper investigated subsequently the mechanical properties of H13 to have a better understanding of the degradation mechanisms. Hardness tests were carried out on different positions on a cutter. Tensile tests and fracture toughness were carried out to investigate temperature effects. The test results showed that the material has a high wear resistance and a good temperature resistance, but its quasi brittle behavior and the residual stress effect (due to the cutting process) is critical for the chipping damage of the disc cutter.

Abstract: For there is a lower level of fusion grid decision-making process and decision-making are not smart enough ,this paper presents a power grid's management and control task demand – knowledge matching model, to help staff accurately and rapidly access to the necessary knowledge, before making a decision.At the same time,in order to solve the problem ,this paper, in the TBM framework ,presents a grid knowledge clustering-ensemble method. Then, knowledge clustering-ensemble model is applied to the electrical network management control decision-making process. Test of the fault diagnosis has proved that ,the model is able to maintain the original good performance of the evidence theory and TBM framework, also can get more useful information for decision-making.

Abstract: In order to study the physical phenomena and mechanical properties of cutters when cutting rock, a test apparatus for cutting performance of cutters of large excavation equipment is established. The test apparatus is composed of a vertical loading system, a rotary loading system, a control system and a test system. Tests of different cut penetrations and spacings were carried out using the test apparatus. Meanwhile, the real-time images of the cutting process and forces acting on the cutters were obtained. The result shows that the test apparatus has good practicality and reliability, and it provides a laboratory test method to study the cutter-rock coupling mechanism and cutting performance of cutters.

Abstract: A Monte Carlo N-particle transport code was used to study physics of the helium-cooled solid-breeder tritium breeding blanket in the Chinese Fusion Engineering Thermal Reactor （CFETR）for various volume ratio of the neutron multiplier and tritium breeder and various thickness of the first wall. A sandwich-type of Be and loading model is used to analyze the compact of volume ratio and the thickness of the first wall for the tritium breeding rate. The results of different volume ratio models show that the tritium breeding ratio would reach 1.51 for volume ratio from 2 to 5.And the results of the different first wall thickness show that the upper limit of the thickness should be 33mm to keep the tritium self-sustain.

Abstract: Cutterhead is one of the key parts of Tunnel Boring Machine, TBM. The performance of cutterhead has a great impact on the boring capability of TBM. The impact heavy torque and thrust force bore by cutterhead during the tunneling process will cause severe vibration and lead to decline in its life even broken, which affect the boring efficiency. In this paper, a TBM mainframe model of Northwest Liaoning project has been built based on the multi-body system dynamics simulation platform ADAMS. It also has been discussed in the paper that the influence of front support on the vibration characteristics of cutterhead. The simulation results show that the front support will improve the vibration behaviors of cutterhead: The stabilization time of rotational and translational motion decreases 90% and 10% at least, the axial amplitude decreases 8%. All these conclusions have demonstrated that front support should be adopted when designing the TBM.

Abstract: Cutterhead is the key part of full-face rock tunnel boring machine (TBM), the design method of mucking slot of TBM is directly related to its tunneling efficiency. In this paper, the coupling model of ballast and mucking structure of TBM is built used the discrete element method (DEM), and the simulation of TBM discharge ballast is made by PFC3D discrete element software. The simulation results show that, the number of particles generated is larger than the eliminated ones at the beginning of the mucking process, but with the change of time, the difference between the numbers of generated and eliminated particles is gradually reduced; the fluctuation of the number of particles within cutterhead is progressively smaller until it becomes stabilized, it fluctuates around the mean and the amplitude of fluctuation is no more than 100. The results in this paper can provide technical support for engineers.

Abstract: The purpose of the essay is to know the rock fragmentation mechanism of TBM and improve the efficiency of disc cutter. The method of simulation is applied. The cutter ring and cutter axis surface stress distribution are studied under different rocks and the change of them is analyzed under different penetrations. Under different rocks conditions, the cutter ring surface stress is affected due to the change of rock load; the same rock condition, it is changed along with the change of penetrations. But the cutter axis surface stress changes little. In different rocks conditions, the change of stress on the cutter ring surface is proportional to rock ultimate stress; the same rock condition, it is proportional to the penetration of the cutter ring. The results are significant in improving the working efficiency of disc cutter.

Abstract: In order to study the disc cutter cutting performance and the cutters combination feature and to explore a new high-efficiency breaking method in hard rock environment, a new multifunction disc cutter test device plan is established and carried out based on the analysis of relevant research and test equipment at home and abroad. The test device consists of a vertical loading mechanism, a longitudinal cutting mechanism, a shock loading mechanism and a control system, etc. It can be used to conduct not only single test such as cutting under static load, fragmentation under impact load, indentation test under static load and wear test of the disc cutter, but also combined cutting test under impact and static load. At last, granite was cut on this test device by the TBM disc cutter under different loads, the results are desirable and show that the test machine can provide the relevant test conditions and the basic data for the design of the TBM disc cutter.