The Method and Displacement Detector for Excluding Dowel Bending Affecting the Accuracy of Spiral Plate Load Test

Abstract

The invention provides a method for eliminating the impacts of dowel bar bending on the accuracy of the spiral plate load test and a displacement detector used in the same. The method and the displacement detector have the beneficial effects and advantages that the problem that the accuracy of the spiral plate load test is impacted by dowel bar bending can be completely eliminated by arranging the displacement detector for detecting the sinking displacement of a spiral bearing plate underground, namely the bottom end of a hollow dowel bar; a linear capacitive grating displacement transducer is adopted for displacement detection; moving and static grating polar plates of the linear capacitive grating displacement transducer are respectively arranged on a hollow force transfer shaft and a drive joint of the displacement detector; during measurement, the position of the drive joint is fixed, that is, the static grating polar plate is fixed, and the moving grating polar plate moves with loading of the hollow dowel bar, thus the displacement of the spiral bearing plate can be accurately detected; a drilling machine is adopted as a rotary pressure device acting on a casing pipe; an oil jack is adopted as a loading device of the hollow dowel bar; the method has the characteristics of mature operation method and extensive adaptability.

Description

technical field [0001] The invention belongs to a load test method for a spiral plate, in particular to a method for eliminating the influence of dowel bar bending on the accuracy of the load test for a spiral plate and a displacement detector thereof. Background technique [0002] The spiral plate load test is suitable for determining the bearing capacity, deformation modulus and other geotechnical parameters of deep foundation soil or foundation soil below the water level, and provides a basis for the design of pile foundations and foundation pits. [0003] The spiral plate load test applies load to the spiral bearing plate through the dowel bar, observes and records the subsidence displacement of the plate after the foundation soil under the plate is compressed, so as to obtain the load-subsidence displacement-time relationship curve of the foundation soil, and then Obtain design parameters such as bearing capacity and deformation modulus of foundation soil at different d...

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