EPB Shield Foam System Test Device And Mechanism Of Foam

Shield tunneling project of modern technology is the core technology, and it is the important symbol measure of a country level of development of construction machinery and equipment . In recent years, China’s major cities in large-scale development of urban rail transportation, more and more necessary to use shield. At present, in the subway construction, the shield machine used for the earth pressure balanced, foam system is the earth pressure balance shield the "key elements", almost all the factory’s earth pressure on the shield machine are equipped with a foam system, bubble has been growing a wide range of applications. However, operating parameters for the foam system is still dependent on the application of engineering experience, this article from the indoor model experiment, the combination of a theoretical basis, made the following aspects:(1) The establishment of the EPB shield bubble simulation test system. The system is equipped with gas, liquid flow meter and pressure gauge. By regulating the size of the flow and pressure can be convenient and efficient access to different gas-liquid ratio and under the pressure of the test data and comparison of multiple sets of test parameters, the accuracy and reliability of data collected. In addition, the system also set a period of observation tube, to facilitate the observation of gas-liquid mixing, gas-liquid two-phase flow pattern and the bubble generation process.(2) The design of the invention of two different mixer, by comparing the test of gas-liquid mixing have been studied and developed a foam regulator, to achieve uniformity of the bubble, fine and stable.(3) By changing the parameters of gas-liquid mixture of different bubble flow patterns were observed and described. Studies have shown that different flow patterns in, the two-phase flows have different characteristics, in engineering, by controlling the flow parameters could have been avoided the emergence of harmful flow patterns in order to ensure the safe operation of equipment.(4) Study the bubble shield system operating parameters and the intrinsic link between the study match the operating parameters of the relationship between the optimization of the operation were discussed. Parameters of gas-liquid mixture ratio of the pilot study is the innovation of this paper.Finally, the full text of the research done by a brief summary of the results and future prospects of the work.