Centrifugal simulation system for freeze thawing deformation of water conveyance canal in salty-cold region

Abstract

The invention discloses a centrifugal simulation system for the freeze thawing deformation of a water conveyance canal in a salty-cold region. The centrifugal simulation system consists of a centrifugal machine, a model box, a water circulation refrigerating plant and a temperature controller, wherein the model box consists of an outer box, an inner box and an interlayer filling material and is used for setting a canal model; the water circulation refrigerating plant consists of multiple semiconductor refrigerating sheets connected with one another in series and a water cooling device; the water cooling device comprises a water pipe, a water pump and a water tank; the temperature controller is used for setting and monitoring the ambient temperature in the model box so as to simulate a real site environment temperature; the model box is arranged in a basket of the centrifugal machine; the semiconductor refrigerating sheets are fixed on the top in the model box; the water circulation cooling device is arranged on a rotating arm of the centrifugal machine; refrigeration plates of the semiconductor refrigerating sheets downwards absorb heat of the canal model; heat dissipation plates of the semiconductor refrigerating sheets dissipate heat through the water circulation cooling device. The technical problems of simulation and testing in the frost heaving-thaw collapse process of the water conveyance canal under the action of a hypergravity field are solved.

Description

technical field [0001] The invention relates to a physical model test system applied to a geotechnical centrifuge, in particular to a simulation test system capable of realizing freeze-thaw cycles on the centrifuge, which is specially used to simulate the frost heaving-thawing deformation characteristics of water delivery channels in cold regions Research. Background technique [0002] There are vast permafrost distributed in the cold regions of northern my country, and the permafrost area alone accounts for more than 1 / 5 of the country's land area. When the depth of the permafrost exceeds 0.5m, there will be obvious freezing and thawing, which will lead to The deformation of the foundation soil of the aqueduct causes the lining of the overlying aqueduct to displace, bulge or even be damaged. The main cause of canal damage in cold regions in my country is caused by frost heave of canal foundation soil. The damage caused by canal frost heave damage accounts for more than 40% ...

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Problems solved by technology

[0004] At present, the physical simulation test methods for studying the freeze-thaw characteristics of water delivery channels are all tested under the constant stress state (1g). This simulation method has two main shortcomings: (1) due to the soil weight Stress is often the dominant factor and occupies a dominant position. However, the indoor small-scale physical model test cannot truly reproduce the real stress state of the canal foundation soil, so that there is still a big difference between the test results and the freeze-thaw situation of the real canal; (2) Constant stress state In the physical model test, the freezing and thawing of the channel is generally completed within a few days or even hours, while the freezing and thawing of the actual channel often takes several months. In terms of the time span simulation of the freezing and thawing of the channel, the 1g normal stress condition The model test is obviously difficult to reflect the real freeze-thaw time span

[0005] The key to simulating the channel freeze-thaw cycle on a centrifuge is to achieve a large temperature change range (minus 40°C-30°C). At present, there are two main methods to achieve negative temperature under constant stress: compressor refrigeration and liquid nitrogen refrigeration. In the first method, the compressor refrigeration equipment itself has a large volume, cannot be tilted and turned over, and can only refrigerate, cannot heat, and cannot adapt to the working environment of the centrifuge; while liquid nitrogen refrigeration requires high-pressure refrigeration equipment, and the connection of the pipeline is very complicated. It is also difficult to apply under the centrifuge

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