Grouting technology used after hollow (hole) ring-shaped steel plate rubber bag (cavity) is installed on pile bottom of cast-in-place pile

Abstract

The grouting technology used after a hollow (hole) ring-shaped steel plate rubber bag (cavity) is installed on the pile bottom of a cast-in-place pile is applicable to the technical field of foundation and underground space engineering. According to the background technology, for a drill hole using mud to protect the wall, if a steel plate rubber bag is installed on the bottom of a reinforcement cage, collapsing of the wall of the drill hole is caused easily, thus sediment on the bottom of the hole exceeds the standard, silt collapsing from the hole wall accumulates on a steel plate easily, and the quality of the cast-in-place pile with the drill hole. According to the technology, a grouting pipe is tied to the reinforcement cage, a hollow ring-shaped steel plate is installed on the bottom, a hollow rubber bag shaped like a car inner tire is installed on the bottom face of the steel plate, a steel plate ring can also be welded to the portion, perpendicular to the bottom face of the steel plate, of the inner side of the hollow rubber bag, the grouting pipe penetrates through the steel plate and communicates with the rubber bag, after the hole is formed, the reinforcement cage is lowered to the hole bottom, if the sediment on the hole bottom exceeds the standard, a guide pipe is utilized for penetrating through a middle hole of the ring-shaped steel plate rubber bag so that secondary clearing can be carried out on the sediment on the hole bottom below, after the standard is reached, concrete is filled, the cast-in-place pile is formed, and after the strength reaches the standard, pressure grouting begins to be carried out on the pile bottom rubber bag through the grouting pipe.

Description

Technical field: [0001] Ground and Foundation Underground Space Engineering Technology Background technique: [0002] At present, in the foundation field, the post-cast-in-situ grouting technology listed in the construction pile foundation specification is open grouting, because the implementation process of open grouting is relatively simple, especially before grouting. The process at the bottom of the hole has little disturbance to the hole wall, but the controllability of the grout injection area of ​​the open grouting is low, and the formation of the enlarged head of the pile tip, the compaction effect on the surrounding strata, and the increase in the bearing capacity of the pile tip It is not as good as closed grouting with a grouting bag (cavity). Although the closed grouting with grouting pocket (cavity) at the bottom of the pile is more superior in terms of orientation, localization and quantification according to the requirements of the "three fixes" of grouting, ...

AI Technical Summary

Problems solved by technology

If a steel plate capsule (cavity) is installed at the bottom of the steel cage as a post-grouting container, in the process of going down to the bottom of the hole with the steel cage, the steel cage with the protective steel plate is like a piston in the drilled hole, and it is easy to form a vortex in the mud water. The mud flow between the edge of the steel plate and the wall of the drilled hole scours and disturbs the wall of the drilled hole, and the steel plate at the bottom is also likely to scratch the wall of the drilled hole. These factors are likely to cause the wall of the drilled hole to collapse, resulting in The sediment at the bottom of the drilled hole exceeds the standard after the grouting container reaches the bottom. At the same time, the silt that collapsed from the wall of the drilled hole is easy to accumulate on the top of the steel plate, which affects the quality of the drilled cast-in-place pile. In severe cases, the pile will be broken. The diameter of the steel plate is relatively small, or due to other reasons such as overfilling of the collapsed hole, the grouting capsule (cavity) at the bottom of the pile will be tightly wrapped by concrete and cannot function. This is also the technical specification for building pile foundations (JGJ94_2008). The main reason why the closed grouting method with grouting pocket (cavity) at the bottom of the hole pile is excluded (see the article description)