Columnar rock sample sealing device and method suitable for true triaxial test

Abstract

The invention discloses a columnar rock sample sealing device and method suitable for a true triaxial test. The device comprises cylindrical pressure heads, a thermal shrinkable sleeve and compressionnuts. Annular bosses are arranged on the cylindrical pressure heads, and external threads are arranged on the annular bosses. A rock sample is clamped between the two cylindrical pressure heads. Annular convex edges are arranged on the compression nuts, and the compression nuts are in screw joint fit with the annular bosses. The cylindrical pressure heads and a rock sample are coated with the thermal shrinkable sleeve, and sleeve openings of the thermal shrinkable sleeve are tightly pressed between the axial side end faces of the annular bosses and the annular convex edges in a sealed mode. The method comprises the following steps: placing the rock sample on the bottom pressure head; sleeving the rock sample with the thermal shrinkable sleeve, and sleeving the rock sample with the compression nut outside the thermal shrinkable sleeve; placing the top pressure head at the top end of the rock sample and enabling the top pressure head to be located in the thermal shrinkable sleeve; heating the thermal shrinkable sleeve to shrink the thermal shrinkable sleeve until the cylindrical pressure heads and the rock sample are completely and tightly wrapped; and cutting off the thermal shrinkable sleeve wrapping the surface of the external threads of the annular bosses, and screwing the two compression nuts to the corresponding annular bosses respectively until the sleeve openings of thethermal shrinkable sleeve are pressed and sealed.

Description

technical field [0001] The invention belongs to the technical field of true triaxial tests, in particular to a rock sample sealing device and method suitable for true triaxial tests. Background technique [0002] At present, when performing rock true triaxial tests, the sealing effect of the rock sample has not been satisfactory to the scientific research personnel, because the heat shrinkable sleeve is needed to seal the rock sample and the indenter, and the heat shrinkable sleeve and the indenter are sealed. It also needs to be sealed to prevent the hydraulic oil in the pressure chamber from entering the rock sample through the gap between the heat shrink sleeve and the indenter. Once the hydraulic oil enters the rock sample, the physical properties of the rock sample will change. At this time The obtained test data will be distorted, so it will lose its practical application value. [0003] At this stage, the sealing of the heat shrinkable sleeve and the indenter is main...

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Problems solved by technology

[0002] At present, when performing rock true triaxial tests, the sealing effect of the rock sample has not been satisfactory to the scientific research personnel, because the heat shrinkable sleeve is needed to seal the rock sample and the indenter, and the heat shrinkable sleeve and the indenter are sealed. It also needs to be sealed to prevent the hydraulic oil in the pressure chamber from entering the rock sample through the gap between the heat shrink sleeve and the indenter. Once the hydraulic oil enters the rock sample, the physical properties of the rock sample will change. At this time The obtained test data will be distorted, so it will lose practical application value

[0003] At this stage, the sealing of the heat shrinkable sleeve and the indenter is mainly achieved by electrical tape winding, but this sealing method has the highest probability of seal failure. This sealing method is mainly used in short-term true triaxial tests, because once Over time, the chance of seal failure increases exponentially

There is another commonly used sealing method, which is to use a metal hoop to tighten the sleeve of the heat shrinkable sleeve on the indenter. The timeliness of this sealing method will be slightly longer than that of electrical tape winding and sealing, but it can only The true triaxial test that satisfies the short and medium time limit, with the continuous expansion of the test subjects, the true triaxial test that needs to be carried out under the long time limit is getting more and more attention, some long time limit tests can even reach several months, in such a long time For a long time, the rock sample needs to be in the ultra-high pressure hydraulic oil all the time, and the seal failure is not allowed, but the sealing method of the metal ferrule cannot meet the reliability requirements of the seal under the long-term effect

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