Anchoring part length design method based on displacement difference/gradient in underground engineering

Abstract

The invention discloses an anchoring part length design method based on displacement difference / gradient in underground engineering. The method comprises the steps that surrounding rock parameters ofsurrounding rock at the underground engineering position are obtained; the type of the anchoring part and the diameter and prestress of the anchoring part are selected; a three-dimensional model of the underground engineering is established; numerical simulation software is adopted to simulate underground engineering excavation to obtain displacement of a certain point of any surrounding rock depth in the same radial direction and displacement of a certain point of rock around a hole under any surrounding rock depth after different active supporting forces are applied; a displacement difference / displacement gradient is calculated at any surrounding rock depth; a displacement difference or displacement gradient change curve of rocks around the hole under the same active supporting force isdrawn; the surrounding rock depth with the displacement difference / displacement gradient smaller than and infinitely close to the limit elongation / limit elongation of the anchoring part in each displacement difference / displacement gradient change curve is selected as the length of the anchoring part; and in all the anchoring part lengths, the anchoring part length meeting the minimum cost principle is selected as the design length of the anchoring part.

Description

technical field [0001] The invention relates to anchorage structures in underground engineering, in particular to a method for designing the length of an anchor piece based on displacement difference / gradient in underground engineering. Background technique [0002] The traditional anchoring design method in underground engineering comes from the design reference in the code, and the value of the anchor (cable) length in the relevant code is mostly based on engineering experience, there is no clear test method or calculation formula, resulting in the anchor ( Cable) length determination lacks effective design guidance. In fact, in the process of tunnel construction, one of the most critical factors to characterize the construction efficiency of bolt (cable) support is the drilling time, and the drilling time and drilling depth are not in a simple proportional relationship; a large number of field experiments have found that, The drilling time of the anchor rod (cable) has a...

AI Technical Summary

Problems solved by technology

[0003] The present invention aims at the deficiencies in current anchor length design, and provides an anchor length design method based on displacement difference / gradient in underground engineering, so as to solve the problem of low support construction efficiency caused by relying on experience to select the anchor length in the prior art

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