Double sleeve for pile foundation test and construction technique thereof

Abstract

The invention discloses a double sleeve for a pile foundation test. The double sleeve comprises an inner sleeve and an outer sleeve, wherein the inner sleeve is concentrically sleeved in a pipe cavity of the outer sleeve; the inner sleeve and the outer sleeve are made of glassfiber reinforced plastic mortar pipes; a plurality of sealing limit grooves are arranged on the surface of the outer wall of the inner sleeve along the axial direction; an O-shaped rubber ring is embedded in the sealing limit grooves; a clearance between the periphery of the O-shaped rubber ring and the inner wall of theouter sleeve is between 2 and 4 mm. The invention also discloses a method for constructing the double sleeve for the pile foundation test, which applies carbon fiber restoration reinforcing technology to carrying out multi-connector integral butting joint adhesion on a pipe section of a glassfiber reinforced plastic mortar double pipe on the ground. The double sleeve has the advantages of light weight, high strength, smooth surface, small frictional resistance between the pipe wall and a soil body, simple construction, safe operation, short construction period and the like, can significantly improve the reliability and accuracy of a result of the pile foundation test, and is applicable to pile foundation bearing tests of various foundation ditches.

Description

Technical field: [0001] The invention involves the construction of the pile foundation before the excavation of the building foundation pit, and especially involves a dual -suite and its construction process method for a pile foundation test. Background technique: [0002] With the rapid development of my country's urban construction, more and more underground construction projects are carried out in cities, such as multi -floor basement, underground parking garage, underground shopping malls, underground rail transit, and cross -river tunnels such as high -rise buildings. With a large number of foundation pit projects, the typical foundation pit project is an underground space excavated from the ground. [0003] Before the excavation of the foundation pit, in order to accurately test the single pile resistance of permanent pile foundation below the bottom of the pit, the following two test methods are generally used: ① During the pile foundation test processThe impact of soil an...

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Problems solved by technology

[0007]2. The friction coefficient between the steel pipe and the surrounding soil is relatively large, so there is still a large lateral frictional resistance between the inner and outer casings and the surrounding soil, so it cannot Completely eliminate the influence of water and soil above the excavation surface on the test results of the single pile bearing capacity in the foundation pit, and the accuracy of the test results cannot be guaranteed

[0008]3. Since there is a large gap between the inner and outer casings, it is easy to pour a large amount of water, soil and slurry, resulting in an increase in the relative friction between the inner and outer casings , thus affecting the accuracy and reliability of the single pile bearing capacity test results

[0009]4. The double-layer steel casing needs to be welded and lengthened on-site at the pile hole opening, so the hoisting operation is difficult, the welding process is complicated, and the safety is low, and the whole hoisting The construction time for welding and sinking to bury the inner and outer steel casings is relatively long

[0010]5. The limit device of the existing inner casing is simple and difficult to operate. The alignment is difficult, so the concentricity and verticality deviation of the inner and outer casings is large, and the verticality of the pile body is difficult to guarantee, which will inevitably affect the accuracy of the ultimate bearing capacity test results, especially when the pile foundation is compressed, its force If the performance is eccentric compression, the accuracy and reliability of the test are more difficult to be guaranteed

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