Large-span grotto excavation construction method

Abstract

The invention relates to a large-span grotto excavation construction method. The method comprises the steps of S1, performing primary support for surrounding rock of each of left, right and middle parts of grotto; S2, excavating the left, right and middle parts of the grotto at the upper part of a channel, and supporting and fixing the upper part grotto on the lower part hard surrounding rock, wherein temporary supports are arranged at the bottom of each part of grotto; S3, excavating the left, right and middle parts of the grotto at the lower part of the channel by adopting a smooth blasting technology; S4, reserving rock pillars between the left part of grotto and the middle part of grotto as well as between the middle part of grotto and right part of grotto at the lower part of the channel; S5, demolishing the temporary supports at the grotto at the upper part, then demolishing the reserved rock pillars in the middle and finally constructing the secondary lining of the whole grotto. Compared with the prior art, the large-span grotto excavation construction method has the advantages of safety, reliability, short construction period, material saving and the like and is particularly suitable for excavating the large-span grotto of which the upper part has a fully weathered stratum and the lower part has hard surrounding rocks.

Description

technical field [0001] The invention relates to a cavern excavation method, in particular to a large-span cavern excavation construction method. Background technique [0002] With the development of urban underground space in my country and a new round of climax in traffic construction, more tunnels with long-span caverns need to be built. Many tunnels pass through the upper part of the weak residual slope soil layer and fully weathered rock layer. , while the lower part is a hard rock formation with better physical and mechanical properties. Due to the poor condition of the upper part of the long-span cavern, the surrounding rock is prone to collapse and roof fall, so in order to ensure the safety of construction in these places, the traditional CD method and the traditional double-side wall pilot pit are generally used for construction. [0003] The division form of the excavation surface of the CD method is as follows: generally, the section of the cavern is divided into ...

AI Technical Summary

Problems solved by technology

[0020] The traditional CD method and the double-side-wall pilot pit construction method require multiple initial supports. The construction period is long and the construction materials are large, which increases the construction cost of the tunnel to a certain extent. It is a long-span cavern in hard rock with good physical and mechanical properties, and the characteristics of hard rock have not been fully considered and utilized.

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