Freeze-thaw cycle model test system and use method thereof

Abstract

The invention discloses a freeze-thaw cycle model test system and a use method thereof. The freeze-thaw cycle model test system comprises a box body shell, a box body inner wall, a heat preservation partition plate, a tunnel cavity, an acceleration sensor, a soil pressure box, a strain gauge, a dial indicator, a temperature sensor, a pressure pump, a brine tank, a liquid nitrogen truck, a cooling pipe, a coil pipe, a loop pipe, a collector, a distributor and a communicating pipe. The arrangement of the inner wall, the outer wall and ancillary facilities of the model box body can bear a frozen and thawed soil layer in a test and carry various measuring instruments, a liquid nitrogen truck, a pressure pump and the like can ensure that freezing and thawing cycle simulation is reasonably carried out, various measuring instruments can monitor the change condition of key factors such as temperature in real time, and corresponding engineering can be conveniently carried out on the test process; the test system can be used for reasonably predicting and exploring the frost heaving effect of the soil body in the seasonal frozen soil region, and analyzing the influence of the frost heaving force on the tunnel structure design.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering tunnels, and in particular relates to a freeze-thaw cycle model test system and a use method thereof. Background technique [0002] Frozen soil is a complex multiphase natural complex, and its structure is also a heterogeneous and anisotropic porous medium. When the soil around urban tunnels undergoes seasonal freeze-thaw cycles, the moisture in the soil exists extremely In the unstable phase transition interval, the original structural damage of the soil will occur, and its engineering mechanical properties will change significantly. At the same time, under the long-term coupling of urban vehicle loads, it is easy to cause road surface diseases and uneven settlement, which will endanger the operation safety of underground pipelines. [0003] At present, research on freeze-thaw cycle soil mainly focuses on indoor triaxial tests and on-site measurements. The technology is relativel...

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Problems solved by technology

[0004] 1. The indoor triaxial test studies the soil unit, and its remodeling and excavation process destroys the original structure of the soil, and cannot truly restore the original stress of the soil;

[0005] 2. There is no sequence between the generation of earth pressure and the freeze-thaw cycle. In the process of triaxial test, the soil sample is frozen and thawed first and then the confining pressure is applied. This is due to the limitation of the instrument;

[0006] 3. During the on-site measurement, it is difficult to arrange measuring points on the outside of the tunnel and inside the soil, and it is impossible to intuitively obtain the deformation and internal force of the soil

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