A kind of expansion similar to conductive characteristics, similar model test materials and how to use

Abstract

The invention discloses a similar-expansibility model test material with the conductivity, and a use method. The similar-expansibility model test material comprises a main body material and an additional material, wherein the main body material is a mixture of an aggregate material and a cementing material; the additional material comprises an expanding agent and a conductive agent; the volume expansion rate of the additional material is 10-30%; the aggregate material is a main material of the similar-expansibility model test material; the cementing material is a cementing and curing materialof the similar-expansibility model test material; the expanding agent enables the aggregate material and the cementing material to have a certain volume expansion after being mixed; and the conductiveagent enables the similar-expansibility model test material to have the conductivity. The invention provides a novel test material having the expansibility and the conductivity and used for testing asurrounding rock stress in a wide range (full field) in a full matching mode, and a test method.

Description

technical field [0001] The invention relates to an expansive similar model test material with conductive properties and a use method thereof, which is suitable for a similar model test for revealing the distribution characteristics of the surrounding rock stress field of underground engineering such as roadways and tunnels, and belongs to the safety technology of mines and underground engineering. Background technique [0002] For a long time, coal has been the main energy source in my country, supporting the rapid growth of the national economy. With the rapid development of my country's economy, the demand for coal resources has increased sharply, and my country's coal mining has gradually entered the deep mining stage from the shallow part. With the increase of coal mining depth, the deep rock mass is in a complex geomechanical environment of "three highs and one disturbance", which makes the mechanical behavior of the deep rock mass more complicated, resulting in severe ...

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Problems solved by technology

[0004] 1. The commonly used similar model test materials are mostly mixtures of river sand, sea sand, quartz sand and other aggregates and cement, gypsum, paraffin and other cementing materials, which can only reflect the strength and deformation characteristics of rocks and coal, but not rocks. Expansion

However, the rock formations around the coal mine roadway are mostly expansive rocks containing montmorillonite, illite and kaolinite, which have a certain degree of expansibility, which leads to the inconsistency between the prepared similar model test materials and the properties of the actual engineering coal and rock mass, resulting in similar There is a certain deviation between the model test phenomenon and the actual engineering situation

[0005] 2. During the loading process of similar model tests, pre-embedded rigid pressure cells or strain bricks made of epoxy resin (usually in the shape of a cube, with a size of about 20-50 mm, and multiple strain gauges are pasted on the six sides) , and connected with the strain gauge and the acquisition instrument through the connecting line) to test the stress distribution state in the surrounding rock of the roadway. On the one hand, the rigidity (elastic modulus) of the strain brick made of the rigid pressure cell or epoxy resin is the same as that of the similar model test material Severe stiffness mismatch (especially for soft rock, the difference in stiffness between the two is 2 to 3 orders of magnitude), resulting in a small deformation of the pressure cell or strain brick during the loading test, and no effective test data can be collected, even if some The test data cannot meet the test requirements due to insufficient collection accuracy of pressure cells or strain bricks; The distribution characteristics of the stress field of the surrounding rock in a large area or the whole site under the condition of excavation and support; if the number of pressure cells or strain bricks is too large, it is equivalent to increasing the strength of similar model test materials, resulting in inaccurate test results

[0006] With the advancement of science and technology, thin-film pressure sensors have been developed (generally in the form of thin sheets or irregular shapes, with flexible size design, many measuring points, and high sensitivity). The stiffness of thin-film pressure sensors matches the stiffness of similar model test materials. However, embedding thin-film pressure sensors in similar model test materials is equivalent to laying artificial joints in similar model test materials, resulting in a decrease in the strength of similar model test materials, and it is easy to produce Detachment phenomenon, which does not match the actual engineering situation

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