A preparation method of through-crack rock mass sample based on 3D printing technology

Abstract

The invention relates to a preparation method of a penetrated crack rock mass test specimen based on a 3D (three-dimensional) printing technology. The method comprises the following steps that (1) the practical crack rock mass is simulated, and a three-dimensional digital model of a mold for manufacturing the test specimen is determined; (2) the mold is obtained through 3D printing, a part used for forming the test specimen crack is printed by water-soluble materials; the surface of the part of the obtained mold is coated with hot melt adhesives; other parts are printed by water-insoluble materials; (3) the physical performance of the practical crack rock mass is simulated, cement mortar is prepared for preparing the test specimen, after the preparation, the cement mortar is poured into the mold, the cement mortar is cured and formed, and the test specimen with the primary shape is formed; (4) the mold for loading the test specimen is dried, and the hot melt adhesives are completely molten and flow out from the crack positions; (5) after the drying, the mold is soaked into water, the water-soluble material parts of the mold are completely dissolved, and the test specimen with the final shape is formed, and is taken out to be dried; (6) demolding and maintenance are performed, and the test specimen is obtained. The preparation method is suitable for being used for preparing penetrated crack rock mass test specimens in different structure types.

Description

technical field [0001] The invention relates to a method for preparing a fractured rock mass sample, in particular to a method for preparing a fractured rock mass sample based on 3D printing technology, and belongs to the field of rock mechanics. Background technique [0002] With the development of water conservancy projects, mining projects, and underground oil and natural gas storage projects in China, fractured rock mass has become a complex medium often encountered in engineering, and cracks have a controlling effect on the mechanical properties of fractured rock mass. The mechanical properties of rock mass are significantly different from those of intact rock mass. Domestic and foreign scholars have conducted in-depth experimental research on the mechanical properties of intact rock mass, but less experimental research has been done on the mechanical properties of fractured rock mass. As a special structure, its internal fracture structure is relatively complex. At pre...

AI Technical Summary

Problems solved by technology

This method uses tin bars to simulate rock cracks, which cannot reflect the complex crack space shape and surface roughness of actual rocks, and the tin bars are easy to break during the mixing process of tin bars and cement mortar, which will affect the size of cracks in rock-like samples. and distribution

[0004] The Chinese invention patent application with the application number 201410139078.1 "Rock-like Specimen Mold for Triaxial Compression Test of Intermittent Double-crack Rock" discloses a bottom, an intermediate frame mold on the bottom, a gland, fixing ears, A rock-like sample mold for making intermittent double-crack rocks with rectangular grooves, but this mold cannot prepare rock-like materials with complex crack structures, and it is not easy to demould

[0005] The Chinese invention patent application "An Indoor Single-crack Rock Sample Preparation Device" with the application number 201110251080.4 discloses a single-crack rock sample preparation device filled with a certain thickness of bonding material. The device consists of a bottom, an upper seat, an upper and lower rock Core fixing collar, threaded spindle, adjusting nut, and fastening nut, which can only prepare rock-like samples with single cracks, and cannot prepare rock-like samples with multiple cracks

[0006] Patent No. ZL201010190001.9 Chinese invention patent "Preparation method of fracture anisotropic seepage medium" discloses a method of processing natural rocks as raw materials into small rock blocks, and then locally bonding the small rock blocks on the contact surface in a predetermined way to form large Scale rock mass, making the gaps between small rock blocks form a three-dimensional crack system in the large rock body, and quantitatively controlling the distribution of cracks in the large rock body, thereby forming an anisotropic rock-like material. Or the surface is bonded into a rock-like material with fractures, which is far from the fracture structure of the actual rock, and cannot fully simulate the actual fractured rock mass

[0007] The Chinese invention patent application "Mold and Method for Making Intermittent Cracked Rock Mass Simulation Specimen" with the application number of 201310641618.1 discloses a mold that includes a bottom plate, a fixed long side plate, a movable long side plate, a movable short side plate, and a grooved bottom pad. plate, grooved top cover plate, and discloses a method of making rock-like materials containing intermittent cracks by inserting metal sheets to form cracks. This method can not fully simulate the crack structure in actual rocks by inserting metal sheets to form cracks , and the metal sheet needs to be pulled out when demolding, which will destroy the fracture structure of the prepared rock-like material

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