Research On Oxygen Supply Criterion And Design Method In The Construction Of Balang High-Altitude Tunnel

With the advancement and implement of OBAOR economic stratagem concept in our country, also the rapid development of the western areas, Sichuan-to-Tibet highway and railway have been put into planning and designing. Thus the number of high-altitude and extra-long tunnels increases rapidly.The influence of altitude height on tunnel construction staff is mainly in two aspects:the staff is in alpine condition because of the temperature decreases with the increase of altitude; the oxygen content will decrease with higher altitude and lower pressure, and finally cause the hypoxia response of staff.Balang Mountain highway tunnel is in line 303 at the height of 3850m. In order to obtain the prediction method of staff needed oxygen in high-altitude tunnel construction, which will provide design basis for oxygen supply technology, the author researched on the relationship between labor intensity and construction order, enacted the relationship between labor intensity and needed oxygen, established the prediction method of oxygen concentration versus tunnel length, and put forward the possible oxygen supply scheme. The research and results are in following aspects:(1)Combined with the relationship of altitude height and human tracheal oxygen proportional pressure based on the investigation and analysis of the impact on the human body function caused by high-altitude environment, initial oxygen-provided height was obtained in high-altitude construction. According to high-altitude labor intensity gradation, labor intensity will increase one level as the height increase of 1000 meters. The labor intensity and altitude height effects on personal oxygen-consume was put forward, and the standard oxygen-provided of construction people was established.(2)The three dimensional model of BaLang mountain tunnel was established, and have a deep analysis of the relationship between oxygen concentration in tunnel and different excavation progress, construction machine power, and oxygen concentration outside, with a fluid mechanics software called Fluent. The calculation results indicate that oxygen concentration decreased gradually with increasing excavation progress, and the oxygen concentration prediction formula in tunnel was established.(3)Based on the prediction methods and the values of tunnel oxygen concentration, construction period oxygen-provided in phase in BaLang mountain tunnel was obtained.(4)Based on field experiment of personal oxygen-provided and diffused oxygen-provided in Balang mountain tunnel, compared the advantages and disadvantages between them, Balang mountain tunnel construction period oxygen-provided scheme was obtained, and optimized method was put forward combined with field measurement of oxygen-provided result.(5)Based on the research and application of oxygen-provided in the construction period, provided a technical support for the implement of constructing Balang mountain tunnel, safely, fast and efficiently, the life-safety of construction people in high-altitude tunnel was ensured, and provided a valuable reference for construction oxygen-provided of subsequent high-altitude tunnel in china.