Method and device for detecting strength of micro pile concrete in peat frozen soil region

Abstract

The invention relates to a peat permafrost region micro pile concrete strength detection method, which comprises the following steps: S10: providing variable pressure conditions for a pressure cavity containing concrete of a sealed kettle body in a manner of injecting pressurized fluid, a variable temperature condition is provided for a pressure cavity, containing concrete, of the sealed kettle body on the basis of the heat transfer effect of the heating fluid; and S20, the concrete is subjected to a setting and hardening reaction, when a preset moment is reached, pressurized fluid is pumped into the fluid conveying pipeline stretching into the concrete body, the form change of the concrete at a pipe opening of the fluid conveying pipeline is observed through the visible window of the sealed kettle body, and the fluid pressure value P corresponding to the preset form at each moment is recorded.

Description

technical field [0001] The invention relates to the technical field of pile foundation construction in permafrost regions, in particular to a method and device for detecting the concrete strength of micro piles in peat permafrost regions. Background technique [0002] Permafrost region, in geology, refers to the upper fissure zone of frozen soil, stone layer and frozen bedrock under the condition of long-term negative annual temperature. Permafrost is a soil medium that is extremely sensitive to temperature and contains abundant underground ice. There is a certain amount of unfrozen water in permafrost. [0003] Frozen soil has certain rheological properties, and its long-term strength is much lower than the instantaneous strength characteristics. Due to these characteristics, construction of engineering structures in permafrost regions must face two major dangers: frost heaving and thawing settlement. The temperature of the frozen layer rises, the permafrost thaws, the ic...

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Problems solved by technology

[0006] However, the existing technology still generally has the following problems: the visual monitoring of the concrete gelation process cannot be realized, that is, the microscopic changes of the concrete in each setting period cannot be observed, and the gel value of the concrete cannot be obtained based on the difference of the concrete in each setting stage. It is not comprehensive and accurate enough to obtain the final evaluation result of concrete bond strength. Secondly, because the microscopic state change of concrete cannot be directly monitored, the concrete’s ability to resist the intrusion of formation fluids is also weak. In addition, the formation environment that can be simulated by the existing technology is relatively limited, especially the simulation of the corresponding pressure and temperature state at different depths of the in-situ formation, so the experimental results and data are usually not reliable enough and lack certain convincingness; More importantly, when carrying out projects based on these experimental simulation data, it will not be able to provide accurate and effective data support for on-site construction, which may increase unexpected construction costs, especially for pile foundation construction in permafrost regions. may additionally cause some unforeseen problems

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