Multifunctional tilt table device used for testing interfacial shear strength characteristics of geotechnical synthetic material

Abstract

The invention discloses a multifunctional tilt table device used for testing the interfacial shear strength characteristics of a geotechnical synthetic material. The multifunctional tilt table device comprises a testing stand, an inclined plane control mechanism, a shearing box unit, a vertical loading mechanism and a measurement and control system, wherein the inclined plane control mechanism drives a tilted plate of the testing stand through a motor so as to allow the tilted plate to rotate to any inclination angle and can fix the tilted plate at a certain inclination angle through hydraulic jacks, shearing boxes are placed on concave guide rails on the surface of the tilted plate, a geotechnical synthetic material sample is installed between upper and lower shearing boxes, multiple layers of inclined shearing interfaces are formed through rotation of the tilted plate, the vertical loading mechanism comprises two loading devices used for short-term and long-term characteristic testing of the interfaces, the measurement and control system composed of a sensor, a control and acquisition system and a computer carries out real-time monitoring on stress and displacement of the upper and lower shearing boxes and the sample, determines a critical interface instability inclination angle according to displacement and pull-up curve abrupt change points and calculates shear strength of each interface according to stress analysis. The multifunctional tilt table device can be used for short-term and long-term characteristic testing of a single layer or multiple layers of interfaces.

Description

technical field [0001] The invention relates to a multifunctional inclined plate instrument for testing the interface shear strength characteristics of geosynthetic materials, which belongs to the technical field of hydraulic structure and material testing. Background technique [0002] Due to the advantages of strong ability to adapt to different deformations, short construction period, low cost, land saving and low-carbon environmental protection, geomembranes are increasingly used as anti-seepage bodies on the upstream face of rockfill dams. The geomembrane anti-seepage body on the rockfill dam surface is generally composed of multi-layer materials such as cushion, composite geomembrane (two cloth and one film or one cloth and one film + geotextile) and protective layer. Due to the low shear strength of the interface between geosynthetic materials such as geomembrane and geotextile and earth-rock materials, the dam surface anti-seepage body composed of multi-layer materia...

AI Technical Summary

Problems solved by technology

However, these two inclined plate instruments cannot meet the requirements of the shear strength test of the interface of the geomembrane anti-seepage body on the dam surface under different working conditions and loading conditions, and their shortcomings are mainly manifested in the following aspects:

[0006] (1) The automation degree of the instrument is low, and the inclination angle of the sample interface is changed by manually rotating the threaded rod or the manual hydraulic jack to lift and rotate the inclined plate. Manual operation will cause uneven rotation speed of the inclined plate, which is prone to jumping rotation. The operation itself will affect the stability of the sample and the reliability of the test results;

[0007] (2) The judgment of the instability of the sample interface is realized by reading the angle between the slant plate and the horizontal plane through the side protractor when the sample slides, which reduces the reliability of the test results and may vary due to different operators. Reflect the speed difference to generate errors;

[0008] (3) Only the shear strength of the single-layer interface can be tested, but for the geomembrane anti-seepage body containing multi-layer interfaces, under different normal pressure and deformation states, it is not known in advance which interface will be unstable, so The existing inclined plate instrument cannot test the shear strength characteristics of the multi-layer interface in the geomembrane anti-seepage body on the dam surface;

[0009] (4) Only the short-term shear strength of the interface can be tested, and the long-term shear strength characteristics of the interface under the consideration of the creep effect of the geosynthetics itself cannot be tested

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