Visual pile sinking digital acquisition device and residual stress measurement method for static pressure pipe piles

Abstract

The invention relates to a visual pile-sinking data acquisition device for a static-pressure pipe pile and a residual stress measurement method. The visual pile-sinking data acquisition device for the static-pressure pipe pile comprises a model box, a reaction frame, a vertical loading system and a data acquisition system; the reaction frame is installed above the model box; the vertical loading system is installed on the reaction frame; the two adjacent side walls of the model box are made of transparent tempered glass; another two adjacent side walls of the model box are made of steel plates; the vertical loading system comprises a servo motor and a vertical pushing rod; a positioning guide pipe is detachably installed on the reaction frame; the positioning guide pipe is positioned under a sleeve; the data acquisition system comprises a pressure sensor and a control panel with an integrated circuit; the pressure sensor is installed on the vertical pushing rod. According to the visual pile-sinking data acquisition device for the static-pressure pipe pile and the residual stress measurement method, disclosed by the invention, the model box is visual; the loading system is automatic; data acquisition is automatic; static-pressure single pile and pile groups are easy to operate; furthermore, residual stress of the tubular pile can be acquired precisely and conveniently.

Description

technical field [0001] The invention relates to a static pressure pipe pile visualization pile sinking digital acquisition device and a method for measuring residual stress. Background technique [0002] PHC pipe pile (prestressed high-strength concrete pipe pile) has become a widely used form of pile foundation due to its advantages of high bearing capacity, strong adaptability, industrialized production and fast construction speed. It is of great significance to study its pile sinking mechanism and bearing capacity properties. In-situ tests are rarely carried out due to factors such as complex test conditions, long test periods, and huge costs. As an effective method, indoor model tests have attracted more and more attention from scholars. The model device is the hardware condition of the test, and its function directly affects the quality of the test and the reliability of the conclusion, so the research and development of the test model device has important scientific re...

AI Technical Summary

Problems solved by technology

[0003] (1) The size of the test model box used by most scholars is generally relatively small, the test will be limited by the size effect of the indoor model, and the research on the resistance and bearing characteristics of pile sinking will inevitably be affected by the boundary effect;

[0004] (2) The current indoor pile-pressing device has no or low-level visualization device, and the observation range of pile-squeezing soil displacement changes is limited. Mesoscopic studies of interactions are inevitably hampered by poor visualization;

This technical solution has the advantages of continuous penetration into the soil and manual control of the pile sinking speed. However, the pile sinking process is still controlled manually by manpower, and the static pressure pile is a slow process that is time-consuming and laborious. Still affected by human factors, the reliability of large measurement results cannot be guaranteed;

[0006] (4) Common static pressure pipe pile tests are mostly single pile tests, and the position of the pile sinking loading system is usually fixed and inconvenient to move. For indoor model tests of pile groups, the pile sinking position needs to be changed many times

[0007] (5) At present, the loading and unloading of the test soil (sand) in the process of test preparation and completion is cumbersome and inefficient. The process of loading the test soil (sand) from the outside of the model box into the box needs to repeatedly cross the height of the high model box. It is laborious to lift the soil in the iron bucket by the test personnel and it is easy to hit the glass side of the model box, which may also have a certain impact on the compaction effect of the soil

The strain gauge is inevitably affected by the extrusion of the soil around the pile, and the chemical material applied on the strain gauge increases the outer diameter of the pile to a certain extent. The entire pile body looks like a "gourd string". The actual force of the pile change, the simulation effect is difficult to achieve

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