Geosynthetic biaxial tension creep tester

Abstract

The invention provides a geosynthetic biaxial tension creep tester. The tester comprises a main frame platform and a cross-shaped tensile testing device arranged on the main frame platform, wherein the cross-shaped tensile testing device comprises four groups of clamping devices, four groups of guiding devices, four groups of displacement sensors and four force-applying devices; the clamping devices are used to clamp the four edges of a test-piece placed in the middle of the cross-shaped tensile testing device and separately connected with the four force-applying devices arranged at the four ends of the cross-shaped tensile testing device through steel cables; the four groups of clamping devices can slide to the force-applying devices separately along the four groups of guiding devices; and the displacement sensors are separately arranged between the clamping devices and the force-applying devices. The geosynthetic biaxial tension creep tester of the invention can be used to perform creep test in any complex stress-strain loading path under the action of biaxial tensile loading, and compared with the easy uniaxial tension test, the creep test is more similar to the actual stress-strain state in engineers.

Description

technical field [0001] The invention relates to a device for testing the bidirectional tensile creep performance of geosynthetic materials, which belongs to the technical field of material performance testing. Background technique [0002] At present, the creep mechanical properties of geosynthetics have been tested by simple uniaxial tensile tests. The test results are quite different from the real stress-strain state of materials in engineering use, and cannot be used to accurately reflect geosynthetics. Creep mechanical properties of materials under long-term tensile loading. [0003] In the tensile test of plate and shell materials in similar fields, there are experimental methods for biaxial tension, among which the cross-shaped tensile method is the most intuitive and reliable one, which can most directly reflect the bidirectional tension of plate and shell materials. method of power state. There are mainly two types of cross-shaped tensile test devices: mechanical a...

AI Technical Summary

Problems solved by technology

The mechanical bidirectional tensile test device is mainly used to apply the load by means of a universal testing machine, which cannot achieve biaxial tensile stress-strain ratio at any rate, and the stretching range of the device is small, so it can only do small deformation tensile tests, which is not suitable for Testing of Geosynthetics under Large Deformation Conditions

The hydraulic biaxial tensile test device applies the biaxial tensile load through hydraulic control. It is very difficult to keep the biaxial tensile force equal or proportional to the hydraulic control, especially when performing small tonnage tensile tests, large errors will occur; in addition , when performing long-term creep tests on materials, the hydraulic drive cannot guarantee the long-term stability and reliability of the tensile load

[0004] The creep test of geosynthetics usually requires a larger sample size to eliminate the influence of boundary effects. In addition, geosynthetics are mostly flexible materials that are prone to large deformation when stretched, so the test device is required to have a wide range of tension. Stretching space, the mechanical bidirectional tensile test device cannot realize the creep test of large specimens and large deformation

The deformation modulus of geosynthetics is small, and generally only a small tonnage of tensile load is required. When using a hydraulic two-way tensile test device in a small tonnage tensile test, a large error will occur, and the creep test of geosynthetics lasted as long as Long-term stability and reliability of tensile loads cannot be guaranteed for hydraulic drives over several months

Therefore, the existing biaxial tensile test instruments for plate and shell materials cannot be directly used for biaxial tensile creep tests of geosynthetics.

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