Medium strain rate test equipment and method with axial pressure and confining pressure controlled loading

Abstract

The invention discloses medium strain rate test equipment and method with axial pressure and confining pressure controlled loading. The equipment comprises a loading frame, an axial loading system, a confining pressure loading system and a high-frequency dynamic strain collecting system. The confining pressure loading system is used for loading confining pressure needed by a test on a rock sample placed in a triaxial confining pressure chamber, and dynamically regulating and controlling the confining pressure change caused by lateral deformation of the rock sample in the test process. The axial loading system is used for loading an axial load required by a test and collecting axial displacement and load data; and meanwhile, displacement servo control is completed through axial and lateral strain fed back by the high-speed and high-frequency dynamic strain acquisition system. According to the invention, a high-frequency-response and high-precision servo measurement and control instrument and a servo valve are adopted to carry out real-time control on the axial and lateral pressure of the rock sample, so that a dynamic triaxial test under a medium strain rate loading condition can be carried out on the sample on the premise of eliminating uncontrollable loading of previous test equipment, and more accurate and stable material mechanical properties can be obtained.

Description

technical field [0001] The invention belongs to the technical field of material mechanics testing, and relates to a medium strain rate test equipment and method with axial pressure and confining pressure servo-controlled loading, which are used to carry out medium strain rate dynamic triaxial tests of materials and obtain their stable mechanical properties. Background technique [0002] More and more engineering projects are constructed in areas with frequent earthquakes and high seismic fortification seismic intensity (earthquake parameters). Earthquake-induced rock mass slope damage and cavern instability are difficult problems faced by the construction and operation of such projects. Generally speaking, the seismic load frequency is within tens of Hz, and the dynamic load and strain range of the rock under these load frequencies is about 10 -2 ~10 2 / s (medium strain rate). Therefore, before commencing the construction of such projects, the site rocks should be at 10 -...

AI Technical Summary

Problems solved by technology

[0003] At present, the dynamic properties of materials under high strain rate loading conditions can be obtained through test equipment such as separate Hopkinson compression bars or light gas guns, and the mechanical properties of materials under low strain rate and creep loading conditions can be obtained through conventional mechanical loading. system or creep test system, but the mechanical properties of medium strain rate loading conditions have been poorly understood due to the limitations of test equipment

In the early days, the driving mode of medium strain rate test equipment was often driven by gas, explosive explosion or gas-liquid mixture, which resulted in the uncontrollable axial loading and confining pressure of the sample, resulting in discrete test results. Therefore, the materials obtained in the past were medium Unstable mechanical properties under strain rate loading conditions are largely caused by imperfect equipment, so the present invention proposes a medium strain rate dynamic triaxial test equipment with axial pressure and confining pressure servo control loading and method, the mechanical properties of the material under this dynamic loading condition can be obtained more stably

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