True triaxial loading and unloading test device and test method for large-scale layered confined rock

Abstract

The invention discloses a true triaxial loading and unloading test device for large-size bedded pressure-bearing rock and a testing method. The device comprises a confining pressure loading module, a sample storage and water outlet module, a confined water loading module, a load loading module and a signal collecting and processing system, wherein the confining pressure loading module comprises two horizontal loading and unloading systems which are independent and perpendicular to each other and is used for performing horizontal load loading and unloading on the wrapped sample storage and water outlet module; the confined water loading module is located at the bottom of the sample storage and water outlet module and is used for performing confined water loading and unloading on the bottom of the bedded rock; the load loading module is located at the top of the sample storage and water outlet module and is used for performing vertical load loading and unloading on the top of the bedded rock; the signal collecting and processing system is used for collecting and analyzing signals in a test process. The test device realizes the true triaxial test of the bedded rock through four independent loading and unloading systems, truly simulates three-way anisobaric stress state of the coal-series bedded pressure-bearing rock and is more true and more reliable than a conventional triaxial test.

Description

technical field [0001] The invention relates to the field of testing the mechanical properties and permeability properties of layered pressure-bearing rocks, in particular to a true triaxial loading and unloading test device and testing method for large-scale layered pressure-bearing rocks. Background technique [0002] my country is rich in coal resources, but the hydrogeological conditions are complicated, which makes geological disasters occur frequently in coal mining. Among them, the floor water inrush during coal seam mining seriously threatens the safe production of coal mines, especially with the increase of mining depth and mining intensity, the water pressure and ground pressure on the floor of the mining face are increasing, and the geological structure environment More and more complicated, making the problem of floor water inrush more common and prominent. Floor water inrush not only caused economic losses and casualties, but also caused serious damage and poll...

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Problems solved by technology

However, this test device is a conventional three-bearing rock test loading device, and its confining pressure is a circular hydraulic loading method. The stress state around the cylindrical rock sample is completely consistent, which is an ideal axisymmetric state and cannot truly reflect The floor rock of the coal seam above the confined water is in a three-dimensional stress state of unequal pressure, which cannot simulate the real three-dimensional stress state of the confined rock, nor can it study the influence of the intermediate principal stress and the anisotropy of the layered rock on its permeability characteristics law

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