Test device and method for simulating two-dimensional loading liquid nitrogen cooling roadway excavation and unloading

Abstract

The invention discloses a test device and a test method for simulating two-dimensional loading liquid nitrogen cooling roadway excavation and unloading. The device comprises a core-drilling drill bit,a cooling and liquid injecting hole, a liquid injecting control switch, a sealing control valve, a drilling stem, a motor, a sliding block, a connecting rod, a rack, a gear, a speed-changing motor, aguide rail, a liquid nitrogen bottle, a bearing, a telescopic support, a rock test sample, a pipeline and a rotating connecting rod. The test method is implemented according to the following steps: 1, fixing a rock test sample; 2, performing two-dimensional loading on the rock test sample; 3, mounting an excavation and unloading test device; 4, simulating round roadway excavation and drilling; and 5, processing and analyzing data. In the process of drilling the rock test sample, the liquid injecting control switch is switched on, the temperature of the drill bit is reduced by injecting liquidnitrogen into the core-drilling drill bit through the cooling and liquid injecting hole, and the problem that the related properties of the rock material is easily weakened by a mode of cooling by water is solved.

Description

technical field [0001] The invention belongs to the technical field of underground engineering excavation, and relates to a test device and method for simulating the excavation and unloading of a two-dimensional loaded liquid nitrogen cooling circular roadway. Background technique [0002] With the rapid development of mines, tunnels and underground plant construction, due to the increase of mining depth, the geological conditions are becoming more and more complex. The excavation and unloading of underground engineering will cause rockburst, large extrusion deformation and partition cracking in the surrounding rock of the roadway. Engineering problems have aroused extensive attention of scholars at home and abroad, and have become hot and difficult research points in the field of rock mechanics. In the process of underground engineering construction, excavation and unloading actually means that the stress of the rock mass on the excavation surface is released, breaking the ...

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Problems solved by technology

[0005] In order to achieve the above object, the present invention provides a test device and method for simulating the excavation and unloading of two-dimensional loading liquid nitrogen cooling roadway, which solves the problem that the simulation method of excavation first and then loading is different from that in a certain stress environment before underground engineering construction. In the process of drilling rock samples, turn on the liquid injection control switch and inject liquid nitrogen into the drilling core bit through the cooling liquid injection hole to reduce the temperature of the drill bit, avoiding the problem that the rock material is easily weakened by water cooling performance issue

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