Flexible jack

Abstract

The invention provides a flexible jack. The jack comprises a cylinder, a piston rod and a piston; the piston divides the cylinder into an upper oil cylinder and a lower oil cylinder, a pressure oil nozzle is arranged on the lower portion of the lower oil cylinder, and a pressure relief oil nozzle is arranged on the upper portion of the upper oil cylinder; a flexible cavity is formed in the portion, away from the ejection end of the piston or on a lower convex block at the bottom of the cylinder, of the piston rod, the flexible cavity is internally provided with a flexible pressure-bearing capsule matched with the cavity shape, a flexible pressure-bearing capsule mat is arranged on the portion, located at an opening of the flexible cavity, of the flexible pressure bearing capsule, the areaof the flexible pressure-bearing capsule mat is equal to the effective output area of the lower oil cylinder, and the flexible pressure-bearing capsule mat is fixedly connected with the opening of theflexible cavity; the flexible pressure-bearing capsule is communicated with the lower oil cylinder through an oil through hole. Accordingly, a force transferring path is definite, the problems that in an existing rock mass mechanics test, a hydraulic (force) steel pillow, the flexible jack and an ordinary jack are used, rock mass stress measurement is inaccurate, compressive rock mass or rigid plate stress is nonuniform, and deformation deviation exits are solved, and the rock mass mechanics test quality is improved.

Description

technical field [0001] The invention belongs to the technical field of rock and soil mechanics and engineering, and relates to loading equipment for rock mechanics tests, in particular to a flexible jack. Background technique [0002] At present, the hydraulic steel sleeper, also known as the hydraulic steel sleeper, is a loading device for rock mechanics tests. It is a flat oil cavity formed by bending and welding two thin steel plates of the same shape. The oil expands and deforms the wall of the oil chamber to squeeze the rock mass, and the contact area of ​​the hydraulic steel pillow with the compressed rock mass or single-layer rigid plate increases with the increase of the output force in the early stage of the force output, and decreases with the increase of the output force in the later stage. If the load is small, the load gradually concentrates, and the force-bearing area cannot be accurately calculated, so the obtained rock mass force is inaccurate. Since the hyd...

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Problems solved by technology

[0004] In order to solve the problem that the hydraulic (hydraulic) steel sleeper used in the existing rock mechanics test is not fully flexible, the contact area between the hydraulic steel sleeper and the compressed rock mass or single-layer rigid plate increases with the increase of the output force in the early stage of force output. In the later stage, as the output force increases, the load decreases gradually, and most of the deformation cannot be recovered. Like other flexible jacks, there are problems that the output force cannot be accurately calculated, and the stroke is short and the output force is small. However, the existing rock mechanics tests are generally in the The surface of the test body is laminated with a single-layer rigid plate and then superimposed with a steel plate, and then loaded with an ordinary jack. The multi-layer transmission causes load loss, and the load is concentrated at the front end of the piston rod. To solve the problems of uneven surface stress and deformation deviation of the compressed rock mass, a flexible jack is proposed. The flexible jack has a clear and simple force transmission path, a reasonable and reliable structure, and is easy to operate, ensuring that the compressive stress at each point of the compressed rock mass is equal. , the force measurement of the rock mass is accurate, the deformation deviation can be eliminated, and the reliability and accuracy of the rock mass mechanics test can be improved

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