CN105651570B - A kind of preparation method containing the prismatical joint rock mass sample without filling blind joint - Google Patents

Abstract

The invention relates to a preparation method of a columnar joint rock mass sample containing hidden joints without filling. Space model; use water-soluble materials to 3D print the 3D digital space models of different types of hidden joints to obtain different types of hidden joint simulation components, and apply hot melt adhesive on the surface of the obtained hidden joint simulation components; prepare cement mortar to simulate the actual columnar joint rock body, the hidden joint simulation component and cement mortar are mixed and stirred into the mold, cured until the sample part is formed; demoulding; the sample part after demoulding is baked, saturated with water, dried, cured, and processed, that is have to. The invention uses 3D printing technology to prepare hidden joint simulating components to precisely control the shape and structure of hidden joints; uses water-soluble materials to prepare hidden joint simulating components, which solves the problem that the hidden joint simulating components cannot be taken out when preparing samples.

Description

A preparation method of a columnar jointed rock mass sample containing hidden joints without filling

technical field

The invention relates to a preparation method of rock mass samples, in particular to a preparation method of columnar joint rock mass samples containing hidden joints without filling, and belongs to the field of rock mechanics.

Background technique

Columnar joints are irregular or regular primary tensile fracture structures formed due to cooling and contraction during the eruption and overflow of volcanic lava. Columnar joints mostly appear in basalt and are widely distributed in Southwest my country. Many of them have been built or are under construction in Southwest China. Large hydropower plants are built on columnar jointed basalt rocks. As a kind of rock mass with special structure, columnar joint rock mass not only has exposed inter-column joint surfaces, but also has hidden joint surfaces inside the columns, which are called hidden joints. The existence of hidden joints leads to the significant anisotropy of mechanical and permeability properties of columnar jointed rock mass, which has a significant impact on engineering safety. Therefore, the study of anisotropy of mechanical and permeability properties of columnar jointed rock mass has high practical and practical engineering value.

Test is a research method often used in the field of rock mechanics. Since the columnar jointed rock mass contains multiple groups of joints and the volume of the column is large, the natural rock samples taken at the engineering site are only limited by the size of the laboratory test specimens. Containing a group of joints or not including joints does not fully reflect the anisotropy of the columnar joint rock mass; and due to the variability of the geometric properties of the columnar joint rock mass, the joints of different rock masses are quite different, and the natural rock samples taken from some rock masses The test results are not fully representative, so the method of artificial sample preparation is usually used to prepare columnar joint rock samples, but the current method for preparing artificial rock samples of columnar joint rock mass is not complete, and only exposed intercolumn joints can be prepared. However, there is no effective method to prepare columnar joint rock samples with unfilled hidden joints, but hidden joints have a significant impact on the mechanical and permeability properties and anisotropy of columnar joint rock mass. Hidden joints cannot fully simulate the properties of columnar joint rock mass in the actual engineering site, so how to prepare columnar joint rock mass samples with or without filling hidden joints has become an urgent problem in the field of rock mechanics testing.

Contents of the invention

Purpose of the invention: The purpose of the present invention is to provide a method for preparing a columnar jointed rock mass sample containing hidden joints without filling. The sample prepared by this method can completely reflect the structure and shape of the internal hidden joints of the columnar jointed rock mass.

Technical solution: The present invention relates to a preparation method of a columnar jointed rock mass sample containing hidden joints without filling, comprising the following steps:

(1) Simulate the structure and shape of the hidden joints in the actual columnar joint rock mass, and determine the three-dimensional digital space models of various types of hidden joints in the samples to be prepared;

(2) The three-dimensional digital space models of different types of hidden joints are 3D printed with water-soluble materials to obtain different types of hidden joint simulation components, and hot melt adhesive is applied on the surface of the obtained hidden joint simulation components;

(3) Prepare cement mortar by simulating the mechanical properties of the actual columnar joint rock mass, mix and stir the hidden joint simulation component with cement mortar, pour it into the mold, and cure it, so that the cement mortar is solidified and formed to form sample parts;

(4) Demoulding the sample parts;

(5) Bake the sample parts until the hot melt adhesive is completely melted, and then carry out water saturation, until the hidden joint simulation components are completely dissolved, dried, cured, and processed to obtain a columnar jointed rock mass sample with no filling hidden joints.

The present invention uses 3D printing technology to prepare hidden joint simulation components, which can accurately control the size, spatial shape, and roughness of joint surfaces of hidden joints; water-soluble materials are used to prepare hidden joint simulation components, and the sample parts can be completely saturated with water Dissolving the components with simulated hidden joints solves the problem that the components with simulated hidden joints cannot be taken out when preparing samples with or without filling hidden joints.

Preferably, the water-soluble material is PVA material.

Specifically, in step (5), the baked sample parts are put into water for vacuuming and saturating. Vacuum saturation can quickly make the sample part reach the saturated state, and the water can fully enter the interior of the sample part.

Preferably, the part of the mold in step (3) in contact with the cement mortar is made of cobalt-chromium alloy material, and hot melt adhesive is applied on the surface of this part. The bonding force between hot melt adhesive and cobalt-chromium alloy is weak, and the bonding force to cement mortar is strong. Apply hot melt adhesive evenly on the surface of cobalt-chromium alloy mold, and block the cement mortar before it solidifies to form the sample parts. The bond between the cement mortar and the mold avoids damage to the structure of the sample parts during subsequent demoulding.

Further, in step (3), the bottom of the mold is provided with a sealed air hole. When demoulding, the air hole is unsealed, and air is blown into the mold from the air hole to make the sample part come out of the mold. The demoulding is convenient and quick without destroying the structure of the sample part.

Preferably, in step (2), the thickness of the applied hot melt adhesive is 0.5-0.6 mm. At this time, the extremely thin hot melt adhesive can completely simulate the roughness of the hidden joint surface or the surface of the actual rock mass.

Specifically, in step (5), the cured sample parts are bonded, cut, and polished to obtain a columnar jointed rock mass sample containing hidden joints without filling.

Beneficial effect: compared with the prior art, the present invention has the advantages of:

(1) For the first time, the present invention applies 3D printing technology to the production of columnar jointed rock mass samples without filling hidden joints, and the three-dimensional digital space model can fully express the type and size of the hidden joints in the prepared columnar jointed rock mass samples , spatial shape and roughness, by using 3D printing technology to make components that simulate hidden joints, the three-dimensional digital space model can be accurately printed into a physical model, and the size, spatial shape, and roughness of the joint surface can be precisely controlled; at the same time, this The invention uses water-soluble materials to prepare hidden joint simulation components, which can dissolve the hidden joint simulation components in the sample parts after being completely saturated with water, and solve the problem that the hidden joint simulation components cannot be taken out in the preparation of samples with or without filling hidden joints; moreover, in Apply hot melt adhesive on the surface of the component to prevent the component from dissolving during contact with cement mortar;

(2) By adopting the cobalt-chromium alloy to prepare the part in contact with the cement mortar in the mold, and applying hot melt adhesive on this part, the bonding of the cement mortar and the mold can be avoided, so that the molded sample cannot be effectively demolded;

(3) By reserving a small hole at the bottom of the mold, when demolding, air is blown into the mold from the small hole to push the sample part out of the mold, and the demoulding is convenient and fast, and the sample will not be damaged The structure of the component or its hidden joints;

(4) The method of the present invention is simple to operate, efficient, fast, and has a wide range of applications. It can prepare different types of non-filling hidden joint columnar joint rock mass samples containing complex structures according to actual needs. Opened up new ideas.

Description of drawings

Fig. 1 is a flow chart of the preparation method of the columnar jointed rock mass sample containing hidden joints without filling in the present invention.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, a kind of preparation method of the columnar jointed rock mass sample that contains no filling hidden joints of the present invention comprises the following steps:

(1) Simulate the structure and shape of hidden joints in the actual columnar joint rock mass, such as the number, size, spatial shape, roughness, etc. of hidden joints, and determine the three-dimensional digital space models of various types of hidden joints in the samples to be prepared ;

(2) Use water-soluble materials, such as PVA materials, to print three-dimensional digital space models of different types of hidden joints into different types of hidden joint simulation components through 3D printing technology, and apply hot melt adhesive on the surface of the obtained hidden joint simulation components;

Applying hot melt adhesive on the surface of the hidden joint simulation component can prevent the component from being dissolved in water during contact with cement mortar; in order to completely simulate the roughness of the hidden joint surface, the thickness of the applied hot melt adhesive can be controlled at 0.5-0.6 mm; High-precision hot-melt glue gun can be used to apply hot-melt glue. The high-precision hot-melt glue gun can accurately control the volume of hot-melt glue ejected, and the accuracy of the applied hot-melt glue can be controlled at about 0.1mm.

(3) Prepare cement mortar by simulating the mechanical properties of columnar jointed rock mass, mix and stir various types of hidden joint simulation components with cement mortar, pour them into molds, and then perform curing to solidify the cement mortar and form sample parts;

The part of the mold in contact with the cement mortar can be made of cobalt-chromium alloy material, and hot melt adhesive is applied on the surface of this part. Since the bonding force between the hot melt adhesive and the cobalt-chromium alloy is weak, the adhesion force to the cement mortar is strong , apply the hot melt adhesive evenly on the surface of the cobalt-chromium alloy mold, before the cement mortar solidifies to form the sample part, block the bond between the cement mortar and the mold, and avoid destroying the structure of the sample part during subsequent demoulding.

Similarly, in order to completely simulate the roughness of the rock mass surface, the thickness of the applied hot melt adhesive can be controlled at 0.5-0.6mm; a high-precision hot-melt glue gun can be used to apply hot-melt glue The volume of the hot melt adhesive can be precisely controlled, and the accuracy of the applied hot melt adhesive can be controlled at about 0.1mm.

(4) Demoulding the sample parts;

A sealed air hole can be set at the bottom of the mold in advance. When demolding, unseal the air hole, blow air into the mold from the air hole, and the sample part can come out of the mold; this method is convenient and quick to demould, and will not Destroy the structure of the sample parts and internal hidden joints.

(5) Bake the sample parts until the hot melt adhesive is completely melted, and then saturate with water until the hidden joint simulation member is completely dissolved. The baked sample parts can be put into water for vacuum saturation and water saturation. It can quickly let the sample parts reach the saturated state, and the water can fully enter the inside of the sample parts; then take out the sample parts after drying, curing, and curing, and process them, such as bonding, cutting, and grinding, to obtain Jointed columnar jointed rock mass specimen.

The present invention applies 3D printing technology to the production of columnar jointed rock mass samples containing hidden joints without filling. Specifically, the 3D printing technology is used to prepare hidden joint simulation components, which can accurately control the size, spatial form, and joint structure of hidden joints. The roughness of the surface can completely reflect the structure and shape of the hidden joints inside the columnar joint rock mass; and the water-soluble materials are used to prepare the hidden joint simulation components, and the sample parts are completely saturated with water, and the hidden joint simulation components can be completely dissolved. The problem that the hidden joint simulation components cannot be taken out when preparing samples with or without filling hidden joints.

Example

Taking the preparation of a columnar jointed rock mass sample without filling hidden joints at the riverbed dam foundation of a certain hydropower station as an example, the preparation method of the columnar jointed rock mass sample containing non-filling hidden joints of the present invention is as follows:

(1) According to the geological data of the columnar jointed rock mass at the riverbed dam foundation of the hydropower station, determine the type, quantity, size, spatial form, and roughness of the hidden joints in the prepared columnar jointed rock mass sample according to the similarity relationship, and make the sample medium 3D digital space models of different types of hidden joints.

(2) Input the 3D digital space model of the hidden joint into the 3D printer, and use the water-soluble PVA material to print out different types of hidden joint simulation components, the size, spatial shape and surface roughness of the printed hidden joint simulation components, Fully simulated the shape of hidden joints in the rock mass of the project site, and evenly applied a very thin layer of hot melt adhesive on the surface of the component with a hot melt gun, with a thickness of 0.5-0.6mm. The hot melt adhesive can be tightly adhered to the hidden joints The surface of the simulated component will not fall off during the process of mixing cement mortar, and at the same time avoid the dissolution of hidden joint simulated components in the process of contacting cement mortar.

(3) Simulate the mechanical properties of columnar jointed rock blocks, prepare samples with cement mortar as raw material, determine the proportion of cement mortar according to the similarity relationship, and finally determine that the sample is composed of ordinary Portland cement, natural river sand and water according to the mass ratio 1:0.5:0.4 mixed, in which the river sand particle size is less than 1mm, adding 0.5% of the total mass of anti-seepage agent and water reducing agent, to strengthen the anti-seepage performance of the material and the fluidity of the cement, reduce the porosity, add a little Defoamer, reduce the generation of air bubbles in the process of cement hydration. According to the type of hidden joints contained in the determined columnar joint rock mass sample and the number of hidden joints of each type, put the corresponding type and quantity of hidden joint simulation components and fully mix with cement mortar, so that the hidden joint simulation components are fully mixed with cement mortar. evenly distributed. The mold made of cobalt-chromium alloy material is used to shape the cement mortar. The bottom of the mold is provided with sealed air holes, and the hot melt adhesive is evenly applied to the part of the mold that is in contact with the cement mortar. Put it into the mold, and maintain it in a constant temperature and humidity box with a temperature of 22°C and a humidity of 90% until the cement mortar is solidified and formed to form a sample part.

(4) Open the sealed air hole at the bottom of the mold, blow air into the mold from the air hole, and make the sample part come out of the mold.

(5) Put the sample parts after demolding into an oven and bake at a temperature of 80 °C to ensure that the hot melt adhesive applied on the surface of the hidden joint simulation member is completely melted, then put the sample parts into room temperature water and evacuate to saturate Water for 2-4 hours to ensure that the hidden joint simulation member is completely dissolved, then take it out and dry it. Then, after curing for 33 days in a constant temperature and humidity box with a temperature of 22°C and a humidity of 90%, a columnar jointed rock mass sample containing hidden joints without filling was obtained through bonding, cutting, and grinding.

Claims (5)

1. a kind of preparation method containing the prismatical joint rock mass sample without filling blind joint, which is characterized in that include the following steps：

(1) structure, the form of blind joint in practical prismatical joint rock mass are simulated, determines the hidden section of various types in sample to be prepared The 3-dimensional digital spatial model of reason；

(2) the 3-dimensional digital spatial model of different type blind joint is subjected to 3D printing using water-soluble material, obtains inhomogeneity The blind joint simulation component of type smears hot melt adhesive in gained blind joint simulation component surface, and the thickness of the hot melt adhesive of smearing is 0.5 ~0.6mm；

(3) mechanical property for simulating practical prismatical joint rock mass prepares cement mortar, and blind joint is simulated component and cement mortar It pours into mold, conserves after mixing, make cement mortar solidification molding, form sample component；Wherein, mold and cement mortar The part of contact is made of cochrome material, and smears hot melt adhesive in the part surface, and the thickness of the hot melt adhesive of smearing is 0.5 ~0.6mm；

(4) sample component is demoulded；

(5) baking sample component melts completely to hot melt adhesive, then carries out full water, is completely dissolved to blind joint simulation component, is dried Dry, maintenance, working process are obtained containing the prismatical joint rock mass sample without filling blind joint.

2. the preparation method according to claim 1 containing the prismatical joint rock mass sample without filling blind joint, feature exist In in step (5), the sample component after baking being carried out into the water to vacuumize full water.

3. the preparation side containing the prismatical joint rock mass sample without filling blind joint according to any one of claim 1-2 Method, which is characterized in that in step (3), the mold bottom sets Packed stomata, during demoulding, by the stomata depressurization, from Stomata blasts air into mold, is removed from the mold sample component.

4. the preparation method according to claim 1 containing the prismatical joint rock mass sample without filling blind joint, feature exist In the water-soluble material is PVA materials.

5. the preparation method according to claim 1 containing the prismatical joint rock mass sample without filling blind joint, feature exist In, in step (5), by the sample component after maintenance through be bonded, cut, polish obtain containing without filling blind joint prismatical joint rock Body sample.