A method of pre-embedding grouting holes in the floor of underground caverns

Abstract

The invention discloses a method for embedment of a grouting hole in a base plate of an underground chamber. The method is characterized by comprising the following steps that (1) a cushion grouting hole embedded pipe is arranged in a concrete cushion of the underground chamber structure; (2) a base plate grouting hole embedded pipe assembly is arranged on the top of the cushion grouting hole embedded pipe, wherein the base plate grouting hole embedded pipe assembly comprises a base plate grouting hole embedded pipe, a grouting hole top sealing cover arranged on the top of the base plate grouting hole embedded pipe, and a grouting hole bottom sealing device arranged at the bottom of the base plate grouting hole embedded pipe; (3) a waterproof layer of the underground chamber is laid up, a plain concrete protective layer is poured, then rebars are bound, and base plate concrete is poured. The method for embedment of the grouting hole in the base plate of the underground chamber has the advantages that during the period of construction completion and operation of the underground chamber, concrete does not need to be removed in a gouging mode in the process of grouting, influence on the externally-wrapped waterproof layer is only caused within the range of the hole diameter of the grouting hole, a grouting pipe can easily, conveniently and directly enter into the soil mass below the base plate and the concrete cushion of the underground chamber, and grouting operation can be carried out.

Description

technical field [0001] The invention is applicable to the method of pre-embedding grouting holes in the floor of cast-in-situ reinforced concrete underground cavern structures (including tunnels, subway stations, etc.) by open-cut method. [0002] technical background [0003] After the underground cavern is completed, underground caverns such as shield tunnels, etc., which will be used for underground excavation at a close distance in the lower part, need to be considered to reserve grouting pipes on the floor of the underground cavern to prevent the later implementation of the underground cavern. Construction disturbs the surrounding soil layer and affects the foundation soil layer of the first underground cavern, which in turn affects the stability of the first built cavern. It is a method to ensure the stable and normal use of the first-built underground cavern by grouting the soil layer through the reserved grouting pipe on the bottom plate. [0004] When the original m...

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Problems solved by technology

[0004] When the original method encounters such a situation, the grouting pipe is generally pre-embedded in the bottom plate, and the nozzle is at a distance from the bottom surface of the bottom plate (thickness is about 50~250mm). This range is all cast-in-place concrete, so the grouting in the later stage needs to be cut through first. The concrete in this section of the bottom slab will inevitably have a certain impact on the original bottom slab concrete. The greater the thickness, the greater the impact, and the more troublesome it will be to remove it. If an external waterproof layer is installed, the impact on the waterproof layer will be difficult to control at the same time

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