A construction method for excavating a large-span cavern

Abstract

The invention relates to a construction method for excavating a large-span cavern, which includes: step S1: first divide the left, right and middle parts into three parts and perform initial support for the surrounding rock of each sub-cavity; step S2: the left, right and middle parts of the tunnel The right and middle parts are excavated, and temporary supports are set at the bottom of each sub-cavern, and the support of the upper part of the cavern is fixed on the lower part of the hard surrounding rock; Step S3: Excavate the left, right and middle parts of the lower part of the tunnel using smooth blasting technology Part three; step S4: rock pillars are reserved between the left and middle chambers of the lower part of the tunnel, and between the middle and right chambers; step S5: first remove the temporary support of the upper chamber, Then remove the reserved rock pillars in the middle, and finally apply the second lining of the entire cavern. Compared with the prior art, the invention has the advantages of safety and reliability, short construction period, material saving, and is especially suitable for excavation of large-span caverns in the upper part of the fully weathered stratum and the lower part of the hard surrounding rock.

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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