The Design Of φ520mm EPB Model Shield Machine And The Simulation Of The Tunneling Test Control

With the rapid development of infrastructure construction in our country, the Shield Method as a safe tunnel construction method with high efficiency has been widely applied in tunnel engineering such as urban subway and underground pipelines and so on. With the superiority of technology and economy, EPB shield machine has been in the overwhelming dominance and become the mainstream in construction technology of urban underground engineering field.At present, there are a series of problems in the shield method to be solved, such as the influence to environment, the matching conditions of construction parameters, etc. Since the shield tunneling is a continuous and dynamic process. To solve those problems, it will be effective to study those by means of excavating with shield machine tunneling model test in the stratum. After analysis and comparison, model test has a particular superiority compared with other study method for the study of shield machine tunneling.The shield-driven interval tunnel of Chengdu subway is taken as the primary basis in this paper. The EPB model shield machine has been designed, and the tunneling test has been canied out in the model stratum. The main research work is as follows:1. The 520mm-in-diameter EPB shield machine model for the test has been designed and manufactured. The similar tests in our country have been summarized in this design, and their shortages have been analyzed. Taking the simulation of the main function of the real shield machine as the design laws, the notion for the model shield machine have been determined. The design specifications about the structure forms, the layout features, the determination of parameters and the specific functions of the shield shell, excavation system, screw conveyor, propulsion device and console board have been provided in detail. The integer parameter and functions of the model shield machine have been generalized.2. The tunneling test has been carried out successfully using the shield machine model and the test platform. According to the precision requirement of the test and the specific conditions, the specific test scheme of tunneling has been brought forward and the measure items have been determined, from the two aspects of ground movement and stress. The control criterion of the tunneling test has been generalized, which includes the press balance between the cutting face and soil chamber, the balance between the cutting amount in theory and the soil discharge amount. Then the two balance relations are applied in the tunneling test. The eight problems involved in the test are solved fairly well, which ensures the success of the test. The general situations such as the preparations at the beginning, the steps of the test and the matters need attention are expatiated.The test datum has been analyzed and generalized and the regularity of the datum are in evidence.