High-efficiency drag reduction double sleeves for pullout test piles and drag reduction method for pullout test piles

Abstract

The invention discloses pulling test pile efficient resistance reducing double sleeves and a pulling test pile resistance reducing method. The resistance reducing double sleeves include the inner sleeve and the outer sleeve. The inner sleeve is sleeved with the outer sleeve, and a certain gap is reserved between the outer sleeve and the inner sleeve. The inner sleeve is in contact with concrete of a test pile, and the outer sleeve is in contact with soil around the pile. An isolation pillar is arranged between the inner sleeve and the outer sleeve so as to control the gap between the double sleeves and improve stability. The pulling test pile resistance reducing method includes the steps that the resistance reducing double sleeves are manufactured and installed, the test pile is drilled and cast, and a pulling test is conducted in a loading manner. Due to a rabbet sealing form at the bottoms of the double sleeves, it is ensured that mud cannot enter the part between the inner sleeve and the outer sleeve, and the purpose of efficiently reducing resistance is achieved. By means of the double sleeves and the method, when a static load test of the pulling test pile is conducted, the test load is directly loaded on a test pile body, the inner sleeve and the outer sleeve slide, and therefore the influences of soil body side friction above the design pile top elevation are eliminated.

Description

technical field [0001] The invention relates to the field of pile foundation construction, in particular to a drag-reducing double sleeve for a pullout test pile and a drag reduction method for a pullout test pile. Background technique [0002] In order to ensure the construction quality, before the construction of important buildings, according to the specifications and design requirements, the construction test piles should be used to check whether the bearing capacity and settlement of the piles under specific site and process conditions are consistent with the design intention, and according to the test results Adjust design parameters. Because the construction unit considers the construction period and other factors, the test piles are generally carried out before the foundation pit of the building is excavated to the design groove bottom elevation, so there will be a section of soil between the engineering pile design top elevation and the actual construction site elev...

AI Technical Summary

Problems solved by technology

[0003] The known technical measure to eliminate the frictional resistance of the test pile is to construct another pullout test pile with equal diameter and length equal to the depth of the invalid soil layer and the corresponding pile anchor, and calculate the pullout test by carrying out the pullout test on the pullout test pile. This method has the following defects: 1. It is necessary to increase the number of test piles and increase the construction cost; 2. The frictional resistance of the invalid soil layer depth is an estimated value, so there are still some errors in the test data

In recent years, although some people have proposed to use double-sleeve technology to reduce frictional resistance, the technology is not perfect. The existing double-sleeve has poor sealing performance. The resistance effect is poor, and the test result is inaccurate

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