Rock stratum double initial support layering method for establishing large-scale underground structure

Abstract

A rock stratum double initial support layering method for establishing a large-scale underground structure mainly includes the following steps: excavating the side headings of an arch part, excavating the upper steps on the middle heading of the arch part, setting the double-layer initial supports of the arch part, setting a mud jacking steel pipe, setting an arch springing girder, excavating the lower steps on the middle heading of the arch part, and three-layered excavating the foundation under the middle heading of the arch part and the two side headings of the arch part. The rock stratum double initial support layering method for establishing the large-scale underground structure combines multiple technologies as advanced small pipe, big pipe shed and section steel support with multiple mining excavation technologies such as PBA method, side drifts-support method, CRD method and step method, not only can satisfactorily control the structural deformation and the stratum settlement, but also has the advantages of simple process, convenience for construction and organization, high construction efficiency, saved project cost and the like.

Description

technical field [0001] The invention belongs to the technical field of tunnel and underground engineering design and construction, and in particular relates to a construction method for constructing large-scale underground structures such as shallow-buried underground excavation large-section single-arch subway stations or tunnels by adopting a double-primary layering method. Background technique [0002] With the development of my country's social economy, many large and medium-sized cities in China have started large-scale subway construction and underground space development. Due to different geological conditions, the structural forms and construction methods of subway stations are quite different, resulting in the diversity of structural forms and construction methods in my country's underground space construction. [0003] In densely populated urban areas, in order to meet the use functions of underground spaces such as subway stations and provide passengers with spaci...

AI Technical Summary

Problems solved by technology

Among them, the side hole method is to construct the two side pilot tunnels first, and requires synchronization, and then construct the middle pilot tunnel. The disadvantage of this construction method is that there are many blocks, many processes, and the greatest disturbance to the ground; the middle tunnel method is that the middle pilot tunnel is carried out first. In construction, the beam and column support system is established, and then the side pilot tunnel is constructed. The disadvantage of this construction method is that there are many blocks, and the excavation of the side pilot tunnel after the middle pilot tunnel is formed is easy to form unbalanced thrust, and the formation is disturbed many times, but The first established beam-column system plays a certain role in controlling land subsidence; the PBA method uses small pilot holes to build piles and beams to form the main force-transmitting structure, and excavates the inner pit under the protection of the arch. However, in order to form the arch cover, in addition to the central column and the upper and lower pilot tunnels, the surrounding side piles, the pile-forming pilot tunnels, and the backfilling of the primary support in the pilot tunnels must also be installed, which increases the cost. Unnecessary amount of engineering, in addition, this construction method also has the disadvantage of relatively harsh construction environment

In addition, in the construction of submerged large-section subway stations or tunnels in rock formations, each construction method has certain adaptability. It is difficult to construct hole-digging piles in small pilot tunnels during PBA construction, and blasting operations are required to form holes. , while the traditional middle hole method and side hole method are difficult to retain the support of the upper layer when the lower layer is blasted

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