Tester for measuring evolution of clay rock shear crack permeability coefficients according to steady-state method

Abstract

The invention relates to a tester for measuring evolution of clay rock shear crack permeability coefficients according to a steady-state method. The tester comprises a shearing box, a water pressure servo loader, a water pressure sensor and an LVDT (linear variable differential transformer) displacement sensor. A clay rock sample is of a flat cylindrical structure with the thickness of 1-2cm. Thewater pressure servo loader is communicated to the upper side of the clay rock sample through a pipeline, provides pore water to the clay rock sample and applies pore water pressure to the clay rock sample. The lower side of the clay rock sample is communicated to the air through a pipeline. The shearing direction of the clay rock sample is parallel to the permeation path of the pore water in theclay rock sample. During shear displacement, the pore water pressure is applied to the upper side of the clay rock sample of the flat cylindrical structure with the thickness of 1-2cm, the lower sideof the clay rock sample is communicated to the air through the pipeline, and a constant water head difference between the upper side and the lower side of the sheared clay rock sample can be formed, so that steady-state seepage is generated, and the permeability coefficients of low-permeability clay rock can be measured accurately according to the steady-state method.

Description

technical field [0001] The invention relates to geotechnical engineering test equipment, in particular to a test machine for measuring the evolution of the permeability coefficient of clay rock shear cracks by using a steady-state method. Background technique [0002] Clay rock is a kind of soft rock whose material properties are between rock and soil. It often has certain plasticity and low permeability coefficient. Internal cracks can generally be slowly closed under hydration. Because of this characteristic, clay rocks (including bentonite blocks) are often used as anti-seepage materials, and are often used as parent rocks and buffer materials for high-level nuclear waste storage around the world. Shear fractures are a common form of cracks in underground caverns of clay rocks, so it is an important subject to study the evolution of the permeability coefficient of clay rocks during shearing. [0003] At present, the permeability evolution of rock and soil materials under...

AI Technical Summary

Problems solved by technology

This method can only measure the permeability of clay rock cracks and the characteristics of the cracks self-closing under the action of water, and the permeability gradually decreases, but cannot measure the evolution of the permeability during the shearing process, and the pre-sheared cracks The loss of cuttings on the fracture surface may also affect the accuracy of the test results

Images