Non-backfill arch open-cut tunnel structure probability reliability degree design method under fallen rock impact

Abstract

The invention discloses a non-backfill arch open-cut tunnel structure probability reliability degree design method under fallen rock impact. The method comprises the steps that a limit state function of an arch open-cut tunnel structure ultimate bearing capacity model, an impact load model of an arch open-cut tunnel by fallen rocks and a non-backfill arch open-cut tunnel structure under the fallen rock impact is built; according to the limit state function, a JC method of a first-order quadric moment method is adopted to calculate a structure reliability index of the arch open-cut tunnel; when the structure reliability index is equal to a target reliability index, and the structure reliability index is larger than the target reliability index and the value which exceeds the target reliability index is smaller than or equal to a set threshold valve, the arch open-cut tunnel structure probability reliability degree which is designed by a selected structure design parameter meets design requirements; when the structure reliability index is smaller than the target reliability index, and the structure reliability index is larger than the target reliability index and the value which exceeds the target reliability index is larger than a set threshold value, the structure design parameter is adjusted until the arch open-cut tunnel structure probability reliability degree which is designed by the selected structure design parameter meets the design requirements.

Description

technical field [0001] The invention relates to the technical field of structural design of arched open tunnels, in particular to a probabilistic reliability design method for arched open tunnel structures without backfill soil under the impact of falling rocks. Background technique [0002] The non-backfill arched open tunnel is mainly used for the protruding portal of the tunnel entrance of the high-speed railway, as a buffer structure to solve the aerodynamic effect caused by the operation of the high-speed train. It has a certain function of preventing dangerous rockfall, and the material is generally reinforced concrete. In order to ensure driving safety, as a light transition section, arched open holes without backfill are also used in the entrance section of highway tunnels, generally in the shape of cut bamboo or bell mouth, and sometimes they are also designed for landscape design and to meet environmental requirements. [0003] For arched open caves located on hig...

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Problems solved by technology

[0004] Aiming at the above-mentioned deficiencies in the prior art, the probabilistic reliability design method of the arched open cavity structure without backfilling soil under the impact of falling rocks provided by the present invention solves the failure of the arched open cavity structure without backfilling soil under the impact of falling rocks in the prior art The problem of calculating probability

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