Osmotic pressure device and testing method used for high-pressure solid bentonite test

Abstract

The invention relates to an osmotic pressure device and a testing method for a high-pressure solid bentonite test. The osmotic pressure device comprises a bottom water injection and exhaust mechanism,a side surface sealing mechanism and a piston, wherein the side surface sealing mechanism is arranged on the bottom water injection and exhaust mechanism, and the piston is inserted into the side surface sealing mechanism and is in sliding connection with the side surface sealing mechanism; the bottom water injection and exhaust mechanism, the side surface sealing mechanism and the piston definea bentonite test cavity, wherein the bentonite test cavity is square, and the height of the bentonite test cavity is smaller than the width; in a test, a bentonite sample parallel to the compaction direction and a bentonite sample perpendicular to the compaction direction are placed in the bentonite test cavity for testing. Compared with the prior art, the method has the advantages that the thickness in the direction of measuring the expansion force and the permeability coefficient direction of the bentonite sample can be reduced, the influence of non-uniform swelling of bentonite is avoided,and the device is suitable for measuring the expansion force and the permeability coefficient of the high-pressure solid bentonite in parallel to the compaction direction and perpendicular to the compaction direction.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering, and relates to an osmotic pressure device and a test method for measuring the swelling force and osmotic properties of high-compacted bentonite. Background technique [0002] One-way compacted bentonite blocks are often used as buffer backfill materials in high-level radioactive waste geological repositories. In the process of unidirectionally compacting the powdery bentonite in the natural state into a high-compacted soil block with a certain dry density, the soil will produce an anisotropic structure, which will lead to anisotropic expansion and permeability characteristics of the high-compacted soil block. opposite sex. [0003] At present, the devices used to study the expansion and permeability anisotropy of high-compacted bentonite can be divided into two categories according to the geometry of the samples used: cube-shaped samples or circular cake-shaped samples. These t...

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Problems solved by technology

However, both types of test devices have certain limitations

For the cube-shaped sample test device, when the sample size is too large, it is difficult to fully saturate the soil; if the size is too small, the device will have a greater impact on the test results, and the size effect will be obvious

For the circular cake-shaped sample test device, the uneven hydration leads to poor representativeness of the data collection points of the expansion force data in the vertical compaction direction, which cannot reflect the overall expansion of the sample

At the same time, since the two types of test devices are equipped with sensors in the lateral direction, it is not conducive to carry out the permeation anisotropy test.

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