A fixture and assembly method for unloading a two-rigid and one-soft true triaxial testing machine

Abstract

A fixture and assembly method for unloading a two-rigid and one-flexible true three-axis testing machine, including four pressing blocks, namely a first pressing block, a second pressing block, a third pressing block and a fourth pressing block. Position control posts are provided in the grooves of the first pressure block, the second pressure block, the third pressure block and the fourth pressure block. The first pressure block, the second pressure block, the third pressure block and the fourth pressure block The grooves are connected end to end to form a square groove, and a limiting baffle is provided in the square groove, and the four faces of the limiting baffle fit with the surface of the position control column; the invention makes up for the "two rigid and one soft" type true three-axis testing machine The shortcomings of the fixture in the unloading test are that when performing a single direction unloading test, the fixture can unload on one side, and the limiting baffle can play a certain role in restricting the rock sample on the other side corresponding to it. Therefore, the failure behavior during the rock unloading test can be studied more extensively, and it also provides the possibility to study the problem of unloading failure disasters at the engineering site.

Description

technical field [0001] The invention belongs to the technical field of rock sample fixtures for true triaxial testing of rocks, and in particular relates to a fixture and an assembly method for unloading a two-rigid-flexible true triaxial testing machine. Background technique [0002] In order to meet the needs of the rapid development of today's society, many large-scale water conservancy and hydropower, mining and geotechnical construction projects have gradually entered the deep part of the earth. At the same time, the disasters of engineering rock mass (especially hard and brittle rock mass) induced by deep high geostress not only cause huge economic losses to the project, but also pose a threat to the personal safety of workers. The failure of engineering rock mass under deep high geostress environment, especially at the excavation boundary, often results in cracking and failure due to excavation and unloading. The rocks in the crust are mostly in the true triaxial str...

AI Technical Summary

Problems solved by technology

However, for the "two rigid and one flexible" type true triaxial testing machine, the oil pressure direction is generally the direction of the minimum principal stress. When unloading the test, the rock sample can only be unloaded on both sides in the oil pressure direction. Unable to unilaterally restrict the rock sample in the direction of the minimum principal stress, this undoubtedly has certain limitations on the study of rock unloading failure behavior, which is not conducive to the study and analysis of disasters such as slabs and rockbursts from a more general situation mechanism

In addition, there are almost no fixtures for single-sided unloading tests in the "two rigid and one flexible" type true triaxial testing machines in China, and the cost of changing the type of testing machine is much higher than the cost of inventing new fixtures

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