Testing system for shield tunnel excavation face stability-losing centrifugal model test under seepage condition

Abstract

The invention discloses a testing system for a shield tunnel excavation face stability-losing centrifugal model test under the seepage condition. An FBG sensor of the testing system guides out a signal through an optical fiber grating, an advanced optical fiber grating sensing technology is used for the shield tunnel excavation face stability-losing centrifugal model test under the seepage condition firstly, the change characteristics of supporting force of the excavation face in the shield tunnel excavation face stability-losing process can be obtained in high-precision and real-time modes, and actual shield tunnel construction is guided. The displacement and retreat rates of an excavation face plate are controlled precisely in real time in a centrifugal field through a geotechnical centrifuge manipulator, the shield tunnel excavation face stability-losing centrifugal model test at different tunnel longitudinal slope angles is achieved through the geotechnical centrifuge manipulator and an angle adjusting device, the conception is ingenious, implementing is easy, and the testing system is reasonable in scheme, simple in structure and conventional in use equipment, and has good economic benefits and social benefits.

Description

Technical field [0001] The invention belongs to the field of tunnel model tests, and specifically relates to a centrifugal model test system for instability of a shield tunnel excavation surface under seepage conditions. Background technique [0002] The stability control of the excavation surface in shield tunnel construction is still a problem to be solved urgently, and the reasonable selection of the support force of the excavation surface is the core issue to solve this problem. The supporting force of the excavation surface is an important reason that affects the stability of the excavation surface and causes soil disturbance. If it is not properly controlled, serious safety accidents will occur. Too little supporting force causes a large amount of soil in front of the excavation to enter the pressure chamber, causing the surface to collapse, while excessive supporting force is likely to cause surface uplift problems and adversely affect surrounding buildings. Therefore, the...

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Problems solved by technology

It can be seen that it is necessary to study the relationship between the ultimate support force of the shield tunnel excavation face and the longitudinal slope angle of the tunnel, but the device does not introduce the relevant content; finally, the instrument used to test the support force of the excavation face is a pressure sensor , is greatly affected by the electromagnetic environment of the test field, and a large bundle of wires formed by the lead-out lines of each measuring point is bundled into bundles, occupying most of the collector ring space, and mutual interference during signal transmission greatly affects the test accuracy

In addition, the size of the geotechnical centrifugal model is small, and the length is between 0.20 and 1.5m. The size of the traditional electrical sensor is generally too large, which will have a great impact on the model under the action of gravity. Therefore, the centrifugal model test requires high speed and stability. , Signal conversion, transmission and processing system with strong anti-interference ability

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