Ultra-large open caisson structure combined foundation construction method

Abstract

The invention discloses an ultra-large open caisson structure combined foundation construction method. The method mainly includes the steps that (1) a medium-coarse sand cushion layer is filled on a mud flat of a to-be-newly-built large circulating water taking area; (2) the medium-coarse sand cushion layer is used as a pile frame bearing layer, and rock-socketed cast-in-situ bored pile construction is conducted; (3) rock-socketed construction is conducted on the lower portion of a cast-in-situ bored pile, reinforced concrete is filled, and the cast-in-situ bored pile serves as a permanent supporting structure of an ultra-large open caisson structure; (4) the pile top of the cast-in-situ bored pile is subjected to compaction grouting, and a soil body at a pile head is reinforced, so that the pile and the soil body form a whole; and (5) an open caisson is manufactured and sunk in a graded mode or integrally sunk in a graded mode, after the open caisson is sunk to a designed elevation, plain concrete bottom sealing is conducted, a reinforced concrete bottom plate is poured, and the rock-socketed cast-in-place piles are connected with the bottom plate to form a whole. According to the ultra-large open caisson structure combined foundation construction method, the problems of sudden sinking and super sinking in the manufacturing and sinking process of the open caisson are effectively solved, and the problem of post-construction settlement after the open caisson is in place is also solved.

Description

technical field [0001] The invention relates to the field of caisson construction, in particular to a super-large caisson structure joint foundation construction method. Background technique [0002] At present, the economy in the southeast coast of my country is developing rapidly, and the demand for electricity is large. Considering the convenience and economy of coal transportation and circulating water intake and drainage, generally large-scale thermal power plants are arranged along the coastline; at the same time, in order to save precious land resources, many coastal large-scale thermal power plants adopt the method of reclamation from the sea, and build land on tidal flats. Arrange buildings. The circulating water system is an important part of thermal power plants. Coastal power plants generally adopt seawater direct-flow cooling, using a large amount of seawater as cooling water to cool the condenser. This requires the construction of a large-scale seawater intak...

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Problems solved by technology

[0003] Tidal flat mud has the characteristics of low foundation bearing capacity, high compressibility, small permeability coefficient and slow consolidation speed. The natural foundation cannot meet the foundation bearing capacity requirements for the construction of large-scale water pumping stations, and appropriate foundation treatment methods must be adopted

At present, the commonly used solution is to use pile foundation, which has the following disadvantages: 1. It cannot meet the stability requirements of caisson fabrication and sinking stage, and it is easy to cause deflection during caisson pouring, sudden sinking and over-sinking during sinking; 2. When taking soil from the caisson, it is easy to cause the surrounding soil to pour into the well, causing the structure of the caisson to tilt, especially for super-large caissons, and it is difficult to correct the deviation; 3. The disturbance of the foundation soil can easily cause the foundation pile to deflect. A broken pile accident occurs; 4. After the pile foundation is deflected, the well body, blade foot and engineering pile foundation are shelved, causing the sinking of the caisson to be difficult

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