Outwards-inclining side wall horizontal bottom-building basin-shaped freezing water-stopping construction method for 8-pilot-tunnel PBA construction method

Abstract

The invention relates to an outwards-inclining side wall horizontal bottom-building basin-shaped freezing water-stopping construction method for an 8-pilot-tunnel PBA construction method. The basin-shaped freezing water-stopping construction method is effectively integrated with the PBA construction method. An outwards-inclining freezing hole is directly constructed with the aid of upper-layer edge pilot tunnels, and the outwards-inclining freezing hole is frozen to form an outwards-inclining side wall; and meanwhile, an additional-excavating vertical shaft and an additional-excavating horizontal channel are continued to be excavated downwards on the basis of an existing vertical shaft, a horizontal freezing pipe is arranged in the additional-excavating horizontal channel, the horizontal freezing pipe is frozen to form a basin bottom freezing bottom plate, and a basin-shaped construction area is formed, so that hydraulic connection inside and outside the excavation area is effectivelyisolated, and the purpose of water stopping is achieved. The construction method does not need to construct additional pilot tunnels and does not need to construct a vertical shaft separately, and thefreeing pipe can reinforce the stratum at a later stage, the cost is not increased, the key construction period is not affected, and the basin-shaped freezing water-stopping construction method has the advantages of zero groundwater extraction, zero pollution, zero external discharging, high adaptability, flexible construction and non-pollution.

Description

technical field [0001] The invention relates to the technical field of excavation and support in deep urban underground spaces, in particular to a freezing and water-stopping construction technique for PBA stations in sensitive urban areas. Background technique [0002] With the development of urban modernization, public transportation can no longer meet the needs relying solely on ground space. The construction of underground railways is the inevitable result of urban development, and it is also a necessary measure to alleviate traffic congestion and encourage public transportation. [0003] Up to now, more than 30 cities in my country have built subways. With the continuous increase of subway mileage, it is also developing in depth. With the gradual increase of the excavation depth, the condition of the soil, the properties of the soil layer, and the stress state are constantly changing, and the groundwater has gradually become an important factor affecting the constructio...

AI Technical Summary

Problems solved by technology

[0006] However, there is currently no effective freezing construction method for PBA stations in urban sensitive areas, nor is it combined with the construction of PBA stations. The freezing effect is not ideal, and a closed or semi-closed frozen wall structure cannot be formed. Effectively freeze the construction area, the freezing efficiency is low, the construction period is long, and it is easy to cause idle work due to freezing construction

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