Design method for probability reliability of arched opencut tunnel with backfill soil under rock-fall impaction

Abstract

The invention discloses a design method for probability reliability of an arched opencut tunnel with backfill soil under rock-fall impaction. The design method comprises the following steps: constructing an arched opencut tunnel structure ultimate bearing capacity model, a model of an impact load of falling rocks to an arched opencut tunnel and an ultimate state equation of the arched opencut tunnel structure with the backfill soil under the rock-fall impaction; calculating a structure reliability index of the arched opencut tunnel by using a JC method in a first-order second-moment method; judging whether the structure reliability index meets the following conditions or not: the structure reliability index is equal to a target reliability index, the structure reliability index is greater than the target reliability index, and the value, which exceeds the target reliability index, of the structure reliability index is smaller than or equal to a set threshold value; if the structure reliability index meets the conditions, showing that the structure probability reliability of the arched opencut tunnel structure with the selected structure design parameter and the backfill soil thickness design meets the design requirement; and if the structure reliability index does not meet the conditions, adjusting the structure design parameter and / or the backfill soil thickness of the constructed arched opencut tunnel until the structure probability reliability of the arched opencut tunnel structure with the selected structure design parameter and the backfill soil thickness design meets the design requirement.

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 with backfill soil under the impact of falling rocks. Background technique [0002] The arched open hole is an effective protection engineering, and the engineering application prospect is broad. Compared with the engineering application of arched open tunnels, the calculation method for rockfall impact force on open tunnel structures has remained at a semi-empirical and semi-theoretical level for a long time. Statistical characteristics and distribution types of rockfall impact loads, and structural failure modes and ultimate bearing capacity under rockfall impact are not clear, and structural reliability analysis and design cannot be carried out. It is an urgent problem to be solved in the current mountainous traffic engineering construction to effectively judge the mec...

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Problems solved by technology

[0003] In view of the above-mentioned deficiencies in the prior art, the probabilistic reliability design method of the arched open cavity structure with backfilled soil under the impact of falling rocks provided by the present invention solves the problem that the failure of the arched open cavity structure with backfilled soil under the impact of falling rocks in the prior art cannot be solved. The problem of calculating probability

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