Uniform water pressure simulation loading device and method for tunnel structure model test

Abstract

The invention discloses a uniform water pressure simulation loading device and method for a tunnel structure model test. The device comprises a top plate (1), a bottom plate (10), stand columns (12), a flexible sealing strip (3), an air extractor (4), a high-precision absolute barometer (5), a tunnel structure model (9) and an electric resistance strain gauge (13). In the tunnel structure model (9), an air pressure detecting hole (7) is connected with the high-precision absolute barometer (5), and air pressure in the tunnel structure model (9) is controlled through coordination operation of the air extractor (4) and the high-precision absolute barometer (5). By the adoption of the equivalent loading method where air pressure instead of water pressure is used, the characteristic that water cannot resist shearing force can be simulated, additional constraints cannot be generated on deformation of a tunnel structure, and therefore the damage process of the tunnel structure can be reflected actually. The permeation effect of water pressure can be simulated, the expansion process of cracks caused by the water pressure can be simulated, and the unloading effect of the water pressure after the cracks are through can be simulated.

Description

technical field [0001] The invention relates to a tunnel structure model test device, in particular to a uniform water pressure simulation loading device and method for tunnel structure model tests. Background technique [0002] In the construction process of tunnel engineering, water problems are common, especially for high-pressure water-rich mountain tunnels and underwater tunnels such as crossing rivers and seas. The structures are all under huge water pressure, and the increasing traffic volume in our country makes the size of the tunnel section larger and larger, which brings more and more complex stress patterns of the tunnel structure. Under the environment of high water pressure, the smaller the ratio of section height to water head height, the smaller the water pressure difference at different positions of the tunnel section, and the less affected the tunnel structure is by the water pressure difference. At this time, the non-uniform Water pressure is regarded as ...

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Problems solved by technology

[0004] 1. Uniform stress loading on the outer surface of the tunnel structure cannot be achieved, which may easily cause local stress concentration at the steel strand, which makes the data of the strain gauge near the steel strand different from the actual one during the test;

[0005] 2. It is impossible to consider the characteristic that water cannot resist shear force. After the steel strand is closely attached to the tunnel structure, the greater the hoop force, the greater the constraint on the deformation of the tunnel structure;

[0006] 3. The deformation of the tunnel structure will cause serious stress loss of the steel strands, resulting in a significant decrease in the equivalent water pressure. To maintain a certain water pressure, it is necessary to repeatedly adjust the stress of each steel strand. The operation is very cumbersome. In actual operation often not possible in

[0007] 4. This method cannot adapt to the external water pressure loading simulation of tunnel lining structures with non-circular cross-sections, because the tension F on the same steel strand is constant, and because the steel strands are closely attached to the tunnel structure, the shape of the tunnel section will change. As a result, the angle θ between the steel strands changes, and the radial force 2Fcos(θ / 2) it provides also changes with the tunnel section. The smaller the radius of the tunnel section, the greater the radial force it provides, which cannot be applied at all. Uniform water pressure, not to mention non-uniform water pressure with small top and large bottom, it should be because the section of the general mountain tunnel structure is that the radius of the upper section is smaller than that of the inverted arch

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