A pretreatment method for subway tunnels before excavation

Abstract

The invention discloses a pretreatment method adopted before a subway tunnel being excavated. The pretreatment method comprises the steps of determining a tunnel central line on the ground, arranging fixed points along the central line at intervals, detecting and excavating an exploratory trench, avoiding pipelines in the exploratory trench to form a plurality of oblique holes and a plurality of vertical holes at different angles, putting steel bars or steel bar cages equal to the hole depth into the holes after hole forming, meanwhile putting grouting pipes into the holes, firstly filling the oblique holes, meanwhile using an instrument to observe the raising situations of the ground and a building and the like. The pretreatment method has the advantages that 1, the pipelines can be visually found out to avoid pipeline drill breakage, 80% of hole distribution positions can be decreased, and interference to operation on streets can be remarkably reduced; 2, the hidden dangers of street surface upheaval, building damage and pipeline breakage caused by grouting can be avoided; 3, a soil body can be efficiently strengthened, underground water stop can be achieved, and the effects of water burst proofing and small soil body deformation in the tunnel excavation process are achieved; 4, a construction period can be remarkably shortened and is only 30% of a construction period of a large pipe shed method or a small guide pipe method.

Description

technical field [0001] The present invention is a combination of extra-long tree root piles and composite grouting technology to effectively avoid underground pipelines, efficiently reinforce soil and underground water stop, especially a pretreatment method for subway tunnels before excavation . Background technique [0002] In the process of subway construction, the excavation of tunnels usually includes open-cut method, shield method and mining method. In the blocks with dense buildings and pipelines, the open-cut method has the greatest impact on buildings, pipelines and markets; shield method The impact is small, but it will also have a strong disturbance and extrusion effect on adjacent buildings, and sometimes cause ground subsidence and pipeline damage; the mining method has the least impact, but effective reinforcement and water-stop pretreatment must be carried out before excavation, so that The soil that the tunnel passes through has better self-stabilization abil...

AI Technical Summary

Problems solved by technology

The above methods all have the problems of ground uplift during grouting, building damage, and pipeline breakage in severe cases. If grouting in the hole, it must be carried out alternately with the excavation process, which will inevitably lead to a very slow excavation speed. If it is constructed on the ground, intensive drilling will be required. Then it is possible to drill underground pipelines such as electric cables, optical cables, water pipes, gas pipes, etc., which are often prohibitive and unable to start construction.

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