Simulation test method of ventilation on-way frictional resistance coefficient of curved tunnel

Abstract

The invention provides a simulation test method of a ventilation on-way frictional resistance coefficient of a curved tunnel and belongs to the technical field of a tunnel ventilation disaster-preventing technology. The simulation test method comprises the following steps of: selecting an appropriate similarity ratio and manufacturing a curved model tunnel and a straight-line model tunnel for rectification section by section; selecting sand paper as an inner surface of the curved model tunnel; connecting the curved model tunnel with the straight-line model tunnel and a rectifying circular tube; connecting the rectifying circular tube with a test fan; mounting static-pressure test tubes on the curved model tunnel at two end points with the length to be detected; inserting a pitot tube into a small test hole of the rectifying circular tube; externally connecting a micro-manometer; providing a test air quantity by the fan; and substituting a measured static pressure difference value and a dynamic pressure value into a formula to calculate the frictional resistance coefficient in the curved model tunnel. By comparing a result obtained by a simulation test with an actual numerical calculation result, the requirement on acceptable precision in engineering is met.

Description

technical field [0001] The invention relates to a friction coefficient simulation test technology in the technical field of tunnel ventilation and disaster prevention. In particular, it relates to the simulation test technology of the frictional resistance coefficient along the ventilation of the curved tunnel. Background technique [0002] At present, when people determine the frictional resistance coefficient along the tunnel ventilation, there are three common methods: (1) the empirical value method, that is, according to the past experience data, the value is randomly selected within a certain range; (2) the field test method , that is, the data is obtained through on-site measurement (see "Testing Research on the Ventilation Resistance Coefficient of Shotcrete Lined Tunnel" in Volume 18, Issue 1 of "Journal of China Highway Society"); (3) Numerical calculation method, that is, by establishing a numerical calculation model, through Calculated by computer. All three met...

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Problems solved by technology

Obviously, in the ventilation design of a curved tunnel, if the empirical value method is used to determine the frictional resistance coefficient, errors will inevitably be caused, especially in the case of a small curve radius and a large corner, the wind flow state is different from that of a straight line. The situation is completely different, and still using the empirical value method may cause unacceptable results

Secondly, the on-site test method can indeed obtain a more accurate coefficient of frictional resistance, but it may cause other adverse consequences due to interference with construction or operation, and it is also impossible to carry out research on the relationship between the coefficient of frictional resistance and the radius of the curve or the corner of the curve, and similar Studies involving different curve radii or corners etc.

Finally, although the numerical calculation method can overcome the shortcomings of the above two methods, when encountering a curved tunnel, the result cannot be effectively confirmed due to the lack of actual test data for verification.

At present, there is no report on the model test method related to the research on the coefficient of frictional resistance along the ventilation of curved tunnels.

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