Model test system and test method for ultimate bearing capacity of foundation piles crossing karst caves

Abstract

The invention discloses a karst cave penetrating type foundation pile ultimate bearing capacity model test system and test method and relates to the technical field of pile foundation manufacturing. The system comprises a test box, a load control module, a data collection module, a foundation pile model, a karst cave model and an analysis display module. The foundation pile model and the karst cave model are both arranged in the test box and are fixed through a stratigraphic model. The inner side of the test box is covered with a smooth film. The top of the foundation pile model is provided with a speed loading device and a displacement detection device. The speed loading device is connected with the load control module. The displacement detection device is connected with the data collection module. A plurality of strain pieces are arranged on the surface of the foundation pile model and are connected with the data collection module. A heating device is arranged in the karst cave model. The data collection module and the load control module are both connected with the analysis display module. Synchronous collection of displacement data and stress-strain data can be achieved, the application range is wide, and necessary test conditions can be provided for the study of ultimate bearing capacity of a karst cave penetrating type foundation pile.

Description

technical field [0001] The invention relates to the technical field of pile foundation manufacture. Background technique [0002] The distribution range of carbonate formations in my country is 3.46 million km2, accounting for about 1 / 3 of the country's land area. Most of the areas have complex geological structures and frequent karst phenomena, which provide sufficient conditions for the formation of underground caves. The pile foundation has the characteristics of strong load transmission capacity, which can effectively reduce the uneven settlement of the foundation, and to a certain extent, reduce the adverse effects of karst caves on the foundation. Therefore, the pile foundation has been widely used in engineering construction in karst areas. When the thickness of the roof of the karst cave does not meet the design requirements of the upper load, the force at the bottom of the foundation pile can cause the roof of the karst cave to collapse. It is a foundation pile tha...

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Problems solved by technology

[0003] At present, there are few research results on the bearing characteristics of foundation piles passing through karst caves, and the research on the force deformation law and instability failure mechanism of such foundation piles is still in its infancy, and the existing research results have not yet revealed the tensile failure area of ​​the karst cave roof The mechanism and its relationship with factors such as span and pile diameter, and the law and mechanism of lateral friction loss in the formation above the cave have not yet been clarified. The method has great theoretical significance and engineering practical value for studying the failure mode and mechanism of its instability, and proposing a calculation method for the ultimate bearing capacity of foundation piles passing through karst caves, and enriching the design theory of ultimate bearing capacity of foundation piles in karst areas

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