Point loading test analysis method based on surrounding rock classification of super-large section tunnel

Abstract

The invention discloses a point loading test analysis method based on surrounding rock classification of a super-large section tunnel. The point loading test analysis method comprises the following steps: obtaining an excavation section area S of a working face; according to different excavation section areas S of a tunnel, adopting N=S / 2 irregular rock block bodies at places near a construction site of the working face; carrying out a point loading test on the irregular rock block bodies on the construction site; calculating according to an engineering rock body test method standard to obtain Is(50); carrying out conversion on the Is(50) obtained by step (4) according to specifications, so as to obtain N Rcs; drawing a histogram, wherein horizontal ordinates are the Rcs obtained by conversion for the point loading test in step (5), the width of the histogram according to the size of extreme difference is reasonably determined, and vertical coordinates are frequencies of corresponding Rc values; carrying out multi-peak normal distribution fitting according to the histogram obtained by step (6) to obtain M normal peaks and the Rc values corresponding to M peak values; determining different surrounding rock rigidity indexes according to the Rc values in ste.p (7), and determining surrounding rock classification of the super-large section tunnel.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a point load test analysis method based on classification of super large section tunnel surrounding rock. Background technique [0002] The geological conditions along the ultra-large-section tunnel are relatively complex. During the tunnel construction, the grade of the surrounding rock exposed on the face of the site is not completely consistent with the classification of the surrounding rock in the design stage. Therefore, it is necessary to analyze the surrounding rock exposed on the face of the construction stage. , to determine the indicators of the surrounding rock classification in the construction stage. The geological parameters for surrounding rock classification in the construction stage can be obtained directly from the working face. The parameters obtained in this way are the most direct and objective, and the surrounding rock classification based on the...

AI Technical Summary

Problems solved by technology

At present, the tunnel excavation section is getting larger and larger, and the surrounding rock conditions are complex. Different grades of surrounding rock grades may appear on the tunnel face at the same time. The Rc obtained from the existing point load test has a large dispersion, and it is impossible to accurately determine the large-section tunnel. The grade of surrounding rock

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