Construction method of one-time excavation for large-section vertical well

Abstract

The invention relates to a construction method of one-time excavation for a large-section vertical well. The method comprises the following steps: from a wellhead to the inner part of a pioneer well with the diameter of 1.4m, approximately horizontal holes radiating in an annular direction are drilled in the pioneer well by using a suspension cage as an operation platform, pore-creating is achieved for one time from the bottom to the top; charging and blasting in a subsection manner are performed from the bottom to the top; slag materials fall to the lower part under the action of gravity; and the one-time excavation of the pioneer well is achieved quickly from the bottom to the top in a subsection manner. According to the technology of the method disclosed by the invention, supporting measures for a temporary well wall are not required; artificial drossing is not required; construction speed is fast; construction safety can be ensured; and construction cost is low.

Description

technical field [0001] The invention belongs to the technical field of underground engineering, and in particular relates to a one-time excavation construction method for a large-section vertical shaft. Background technique [0002] At present, in large-scale water conservancy and hydropower projects, there are often vertical shaft projects with large cross-sections. Generally, raise drilling rigs are used to construct pilot wells first, and then drill and blast methods are used to excavate. The diameter of the pilot well is generally 1.4m. After the completion of the raising drilling rig, the well wall of the pilot well is smooth and compact, but the diameter of the pilot well of 1.4m is too small, and well plugging accidents are likely to occur during the subsequent excavation construction, and manual slag removal work The amount is large. In order to meet the needs of subsequent excavation and slag removal and avoid well blockage, excavation is generally divided into two...

AI Technical Summary

Problems solved by technology

According to the current construction methods of domestic hydropower projects, one-time excavation is generally divided into two methods: top-down excavation or bottom-up excavation, both of which adopt vertical hole blasting, and top-down excavation requires manual cooperation with slag removal , and the temporary shaft wall formed after one excavation often has dangerous rocks, etc., temporary support measures must be taken to ensure safety, and temporary support measures will increase construction costs, low work efficiency, and high construction costs; bottom-up During excavation, the excavation pit face is always located above the operator, and dangerous rocks on the pit face are more likely to cause injury to the operator, and there is a greater potential safety hazard, and temporary support measures must be taken for the temporarily excavated well wall

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