Improved pile foundation vertical bearing capacity test reverse self-balanced method and testing device

Abstract

The invention discloses an improved pile foundation vertical bearing capacity test reverse self-balanced method and a testing device. The testing device comprises a poured upper pile section, a poured lower pile section, a load box arranged in a middle pile section, a test control unit and a displacement measuring instrument. An anchor cable free section penetrates through an insulation pipe in the upper pile section and extends out of the top of the upper pile section by a certain free length. Loading oil cylinders are arranged between the anchor cable free section and the top of the upper file section. An anchor cable fixed section is fixedly connected with the lower pile section. A displacement rod connected with the displacement measuring instrument is arranged on the upper pile section and the lower pile section. The load box is loaded to make the upper pile section and the lower pile section displace oppositely at first; the loading oil cylinders at the top of the upper pile section are loaded to make the upper pile section and the lower pile section displace relatively; and finally, the load box is recovered, the middle pile section is poured, and the bearing capacity conditions and displacement deformation of a pile foundation under two conditions are recorded correspondingly. According to the self-balanced method and the testing device, negative friction of the upper pile section and the defect that the load box cannot be recovered through traditional self-balanced methods are overcome, the operation is simple, and the cost is low.

Description

technical field [0001] The invention relates to a method for detecting the vertical bearing capacity of a pile foundation in the engineering field, in particular to an improved reverse self-balancing method and a test device for the vertical bearing capacity test of a pile foundation. Background technique [0002] The traditional self-balancing method was first proposed and implemented by Israel Afar Vasela Company in the 1960s, and applied for a patent for "a new test method for bearing capacity", commonly known as "Tongmo static load method". The detection principle is to embed a special loading device—the load box, into the corresponding position in the pile together with the steel cage before concrete pouring, and lead the pressure tube of the loading box and other required testing devices from the pile body to the pile. ground, and then poured into piles. A booster pump pressurizes the load box on the ground to generate a loading force inside the pile body, and the bea...

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Problems solved by technology

If the selection is not appropriate, one section has been deformed to destruction, and the other section has not moved, in this case the test pile will fail.

[0008] 4. The pile body is broken at the loading place at the pressure box. Although there is a method of filling this place by grouting, it is difficult to control and detect the quality, so this kind of pile cannot be used for engineering piles

[0009] 5. The load box is embedded in the pile body. After the test is completed, it cannot be recycled and reused, and a certain amount of equipment investment is required.

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