Low-strength high-impact-tendency similar simulation material and preparation method thereof

Abstract

The invention discloses a low-strength and high-impact-tendency similar simulation material and a preparation method thereof. The low-strength and high-impact-tendency similar simulation material is prepared from 10-90 parts of coal gangue; 90 to 100 parts of flue gas desulfurization gypsum; 35 parts of water; the mass of the polycarboxylic acid high-efficiency PC water reducing agent accounts for 0.1% of the total mass of the powder; the mass of the gypsum retarder accounts for 0.05% of the mass of the flue gas desulfurization gypsum. The coal gangue and the flue gas desulfurization gypsum are used as main raw materials, the polycarboxylic acid high-efficiency PC water reducing agent and the vegetable protein retarder are used as admixtures, and active ingredients of the coal-based solid waste are utilized to obtain the coal analog simulation material with low strength and high impact resistance. The problems that the impact power damage phenomenon of the current coal similar simulation material is not obvious, the strength and the impact are not matched and the like can be solved; moreover, recycling of solid wastes is realized, and dependence on natural resources is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of simulation materials, and in particular to a low-strength and high-impact tendency similar simulation material and a preparation method thereof. Background Art

[0002] Since dynamic disasters such as rock burst are instantaneous and sudden, it is difficult to monitor rock burst in a timely manner at the coal mine site.

[0003] The process of pressure generation and real-time accurate prediction. Physical simulation is a simulation method that can realistically simulate the relationship between complex underground engineering structures, complex geological structures, and complex underground rock formation combinations. It can qualitatively or quantitatively respond to the stress characteristics of rock masses, provide a basis for establishing new theoretical and mathematical models, and obtain the mechanism and response characteristics of deep geodynamic disasters. Therefore, conducting three-dimensional physical simulation of underground engineering under complex geological conditions has both theoretical value and practical engineering significance. Making similar models for similar simulation tests is an important part of physical simulation, and the key to affecting the accuracy and reliability of the test is how to select similar materials and determine the ratio so that the model and the prototype achieve a certain similarity. Moreover, the existing invention patents are mainly aimed at the research on the characteristics of water-rich and coal gas outbursts, but there are relatively few studies on similar materials with strong impact tendencies.

[0004] The impact tendency of coal is an inherent property of natural coal bodies due to changes in geological sedimentation. It is also a sufficient condition for rock burst. However, there is a contradiction between low strength and high impact tendency of existing similar materials. Low-strength materials are mostly plastically damaged, and the form of failure in large-scale model tests is mostly the collapse of the overlying rock strata. The high impact tendency of a material is usually expressed as high strength, which means that the material can only qualitatively show rupture on a testing machine with a small-size specimen. Due to the limitations of the loading capacity of the testing machine and the attenuation characteristics of the material's stress transfer, the occurrence of impact damage in a large-scale model cannot be achieved.

[0005] Therefore, there is an urgent need to develop a similar material with low strength and high impact resistance that can simultaneously meet the needs of small-scale qualitative destruction and large-scale model impact tests. Summary of the invention

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is: a low-strength and high-impact tendency similar simulation material and a preparation method thereof, wherein the coal gangue is 10 to 90 parts;

[0007] Flue gas desulfurization gypsum is 90-100 parts;

[0008] Water is 35 parts;

[0009] Polycarboxylic acid high-efficiency PC water reducer, the mass accounts for 0.1% of the total mass of the powder;

[0010] Gypsum retarder, the mass of which accounts for 0.05% of the mass of flue gas desulfurization gypsum.

[0011] Furthermore, the main components of the coal gangue are SiO2 and Al2O3, and the median particle size of the particles is 9.674um.

[0012] Furthermore, the main component of the flue gas desulfurization gypsum is CaSO 4 ·2H 2 O, the median particle size of the particles is 25.605um.

[0013] Furthermore, the gypsum retarder is a plant protein retarder, and the addition amount is 0.01-0.1%.

[0014] Furthermore, the chloride ion content of the polycarboxylate superplasticizer is not more than 0.6%, and the total alkali content is not more than 15%. The polycarboxylate superplasticizer molecule in the present invention contains a polyether side chain with strong hydrophilicity and a main chain composed of multiple active groups. Due to the special molecular structure of the polycarboxylate superplasticizer, the solid particles are caused to produce space stacking and electrostatic repulsion, and the polycarboxylate superplasticizer has a strong dispersibility and is more effective in regulating the fluidity of the slurry than other types of superplasticizers.

[0015] Furthermore, the water is tap water at room temperature.

[0016] Further, by weight, the coal gangue is 50 parts, the flue gas desulfurization gypsum is 50 parts, the water is 3.5 parts, the polycarboxylic acid high-efficiency water reducing agent is 0.5 parts, and the gypsum plant protein retarder is 0.25 parts. The gypsum plant protein retarder used in the present invention is a white powder, which prevents the direct contact between the semi-hydrated gypsum particles and water, slows down the dissolution rate of the semi-hydrated gypsum, thereby delaying the formation of dihydrate gypsum crystal nuclei and the growth of crystals, thereby controlling the setting time of the gypsum.

[0017] A method for preparing a similar simulation material with low strength and high impact, comprising the following steps:

[0018] (1) Pre-mixing: pre-mix the coal gangue, flue gas desulfurization gypsum, polycarboxylic acid water reducer and gypsum vegetable protein retarder in a mixer for 3 minutes;

[0019] (2) Add water and stir: slowly add the prepared water into the mixer containing the solid material and stir at a uniform speed to avoid the formation of bubbles and slurry fracture surfaces;

[0020] (3) Standing: Stir until there are no flocs or bubbles in the slurry, and let it stand for 1 to 2 minutes;

[0021] (4) Mold filling and curing: The slurry is poured into the test mold and cured in a standard curing box until the initial setting state is reached, and then the mold is removed. The demoulding specimen is cured at room temperature for 14 days to obtain a similar material specimen with low strength and high impact tendency;

[0022] (5) Mechanical properties test: After 14 days of room temperature curing, the mechanical properties test can be carried out.

[0023] The advantages of the invention compared with the prior art are:

[0024] (1) The present invention uses coal gangue and flue gas desulfurization gypsum as main raw materials, polycarboxylic acid high-efficiency PC water reducer and plant protein retarder as admixtures, and utilizes the active ingredients of coal-based solid waste to obtain a low-strength and high-impact coal-like simulation material. It can not only solve the problems of the current coal-like simulation material's lack of obvious impact dynamic damage phenomenon and mismatch between strength and impact, but also realize the resource utilization of solid waste and reduce dependence on natural resources.

[0025] (2) The similar simulation material produced by the present invention uses coal gangue as aggregate and flue gas desulfurization gypsum as binder. On the basis of ensuring that similar conditions are met, the brittleness of the specimen and the bonding capacity between aggregate particles are increased, which makes up for the deficiency of weak dynamic destruction of impact-prone coal in the past, and further provides support for the simulation of similar materials of strong impact-prone coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The finished product stress-strain curve diagram and macroscopic failure diagram of a similar material specimen with low strength and high impact tendency prepared in Example 1 of the present invention.

[0027] Figure 2 This is a microscopic cross-sectional view of a finished product of a similar material specimen having low strength and high impact tendency prepared in Example 1 of the present invention.

[0028] Figure 3 This is the acoustic emission diagram of the finished product of a similar material specimen with low strength and high impact tendency prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0030] The present invention is described in detail with reference to the accompanying drawings.

[0031] The present invention provides a low-strength and high-impact tendency similar simulation material and a preparation method thereof in a specific implementation, including powder weight components:

[0032] Coal gangue is 10 to 90 parts;

[0033] Flue gas desulfurization gypsum is 90-100 parts;

[0034] Water is 35 parts;

[0035] Polycarboxylic acid high-efficiency PC water reducer, the mass accounts for 0.1% of the total mass of the powder;

[0036] Gypsum retarder, the mass of which accounts for 0.05% of the mass of flue gas desulfurization gypsum.

[0037] The composition and content of the following coal gangue (CG) and flue gas desulfurization gypsum (FDG) are shown in the following table:

[0038] <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> <![CDATA[Fe 2 THE 3 ]]> MgO CaO <![CDATA[Na 2 The]]> <![CDATA[K 2 The]]> <![CDATA[TiO 2 ]]> <![CDATA[MnO 2 > CG 61.7 25.74 4.13 0.8 1.18 0.4 2.36 0.9 0.06 FDG 0.806 1.275 - 1.166 0.211 57.521 - 37.272 0.04

[0039] Embodiment 1:

[0040] In this embodiment, a similar material with low strength and high impact includes coal gangue, flue gas desulfurization gypsum, polycarboxylic acid high-efficiency water reducing agent, vegetable protein retarder and water, wherein the coal gangue is 50 parts, the flue gas desulfurization gypsum is 50 parts, the water is 3.5 parts, the polycarboxylic acid high-efficiency water reducing agent is 0.5 parts, and the gypsum vegetable protein retarder is 0.25 parts.

[0041] A similar material with low strength and high impact is prepared as follows:

[0042] (1) Pre-mixing: pre-mix the coal gangue, flue gas desulfurization gypsum, polycarboxylic acid water reducer and gypsum vegetable protein retarder in a mixer for 3 minutes;

[0043] (2) Add water and stir: slowly add the prepared water into the mixer containing the solid material and stir at a uniform speed to avoid the formation of bubbles and slurry fracture surfaces;

[0044] (3) Standing: Stir until there are no flocs or bubbles in the slurry, and let it stand for 1 to 2 minutes;

[0045] (4) Mold filling and curing: The slurry is poured into the test mold and cured in a standard curing box until the initial setting state, and then demolded. The demolded specimen is cured at room temperature for 14 days to obtain a similar material specimen with low strength and high impact tendency; the size of the similar material specimen with low strength and high impact tendency is the standard rock mechanics test size of φ50×100mm.

[0046] (5) Mechanical properties test: After 14 days of room temperature curing, the mechanical properties test can be carried out using a testing machine.

[0047] In order to reduce the experimental error, 6 specimens were prepared in each group using the same sample preparation method, and the average value was calculated as the final experimental result. Figure 1 The stress-strain curve of the similar material specimen is shown in Figure 2. Through testing, the density of the similar material specimen is 1.4g / cm3, the elastic modulus is 1.17GPa, the internal friction angle is 22°, and the internal cohesion is 0.68MPa, which are similar to the physical properties of raw coal.

[0048] According to GB / T 25217.2-2010 "Classification of impact tendency of coal and determination method of index", the impact tendency of similar material specimens in the embodiment was identified, and the dynamic failure time was 55ms, the elastic energy index was 7.4, and the uniaxial compressive strength was 3.98MPa. Finally, according to the fuzzy comprehensive evaluation, the result was Class III strong impact tendency.

[0049] Embodiment 2:

[0050] Same as Example 1, except that the coal gangue is 60 parts, the flue gas desulfurization gypsum is 40 parts, the water is 3.5 parts, the polycarboxylic acid high-efficiency water reducing agent is 0.5 parts, and the gypsum vegetable protein retarder is 0.25 parts.

[0051] According to GB / T 25217.2-2010 "Classification of impact tendency of coal and determination method of index", the impact tendency of similar material specimens in the embodiment was identified, and the dynamic failure time was 65ms, the elastic energy index was 8.85, and the uniaxial compressive strength was 5.89MPa. Finally, according to the fuzzy comprehensive evaluation, the result was Class II weak impact tendency.

[0052] Embodiment three:

[0053] The same as Example 1, except that the coal gangue is 70 parts, the flue gas desulfurization gypsum is 30 parts, the water is 3.5 parts, the polycarboxylic acid high-efficiency water reducing agent is 0.5 parts, and the gypsum vegetable protein retarder is 0.25 parts.

[0054] According to GB / T 25217.2-2010 "Classification of impact tendency of coal and determination method of index", the impact tendency of similar material specimens in the embodiment was identified, and the dynamic failure time was 55ms, the elastic energy index was 4.87, and the uniaxial compressive strength was 6.8MPa. Finally, according to the fuzzy comprehensive evaluation, the result was Class II weak impact tendency.

[0055] The coal-similar material with low strength and high impact prepared in Example 1 is highly consistent with the original coal in terms of physical properties. By flexibly adjusting the material ratio, it is possible to ensure that the similar material exhibits specific impact tendency characteristics, thereby accurately simulating the dynamic failure characteristics of coal rocks with low strength and high impact. With the help of the test pieces produced by the present invention, a systematic quantitative study can be carried out, which can provide key and necessary parameters for the subsequent construction of a large-scale rock burst similar physical model. This not only helps to truly reproduce the occurrence process of rock burst in a laboratory environment, but also has a positive role in promoting in-depth exploration of rock burst prevention and control strategies. In addition, the present invention has significant advantages: few types of materials are required, the source is wide and the cost is low, the preparation process is simple, and the operation is convenient. These characteristics make the invention widely practical in practical applications and have extremely high promotion value.

[0056] As a further elaboration of the present invention, the main components of the coal gangue are SiO2 and Al2O3, and the median particle size of the particles is 9.674 um.

[0057] As a further elaboration of the present invention, the main component of the flue gas desulfurization gypsum is CaSO 4 ·2H 2 O, the median particle size of the particles is 25.605um.

[0058] As a further elaboration of the present invention, the gypsum retarder is a plant protein retarder, and the amount of the gypsum retarder added is 0.01-0.1%.

[0059] As a further elaboration of the present invention, the chloride ion content in the polycarboxylate high-efficiency water-reducing agent is not more than 0.6%, and the total alkali content is not more than 15%.

[0060] As a further elaboration of the present invention, the water is tap water at room temperature.

[0061] As a further illustration of the present invention, by weight, the coal gangue is 50 parts, the flue gas desulfurization gypsum is 50 parts, the water is 3.5 parts, the polycarboxylic acid high-efficiency water reducing agent is 0.5 parts, and the gypsum vegetable protein retarder is 0.25 parts.

[0062] A method for preparing a similar simulation material with low strength and high impact, wherein the mixer in step (2) is a JJ-5 cement slurry mixer.

[0063] A method for preparing a similar simulation material with low strength and high impact, wherein the testing machine is an electro-hydraulic servo electronic universal testing machine, with a maximum range of 1000KN, a test force measurement accuracy of 0.5%, a sampling frequency of 1000Hz, a displacement measurement accuracy of 0.5%, and a deformation measurement accuracy of 0.5%. The above describes the present invention and its implementation methods, which are not restrictive. What is shown in the accompanying drawings is only one of the implementation methods of the present invention, and the actual structure is not limited to this. In short, if ordinary technicians in this field are inspired by it, without departing from the purpose of the invention, without creatively designing structural methods and embodiments similar to the technical solution, they should all fall within the scope of protection of the present invention.

Claims

1. A low-strength and high-impact tendency similar simulation material, characterized in that: Including powder weight components: Coal gangue is 10 to 90 parts; Flue gas desulfurization gypsum is 90-100 parts; Water is 35 parts; Polycarboxylic acid high-efficiency PC water reducer, the mass accounts for 0.1% of the total mass of the powder; Gypsum retarder, the mass of which accounts for 0.05% of the mass of flue gas desulfurization gypsum.

2. The low-strength and high-impact tendency similar simulation material according to claim 1, characterized in that: The main components of the coal gangue are SiO2 and Al2O3, and the median particle size of the particles is 9.674um.

3. The low-strength and high-impact tendency similar simulation material according to claim 1, characterized in that: The main component of the flue gas desulfurization gypsum is CaSO4·2H2O, and the median particle size of the particles is 25.605um.

4. A low-strength and high-impact similar simulation material as claimed in claim 1, characterized in that: The gypsum retarder is a plant protein retarder, and the amount of the retarder added is 0.01-0.1%.

5. A low-strength and high-impact similar simulation material as claimed in claim 1, characterized in that: The chloride ion content of the polycarboxylate high-efficiency water reducer is not more than 0.6%, and the total alkali content is not more than 15%.

6. A similar simulation material with low strength and high impact as claimed in claim 1, characterized in that: The water is normal temperature tap water.

7. A similar simulation material with low strength and high impact as claimed in claim 1, characterized in that: Calculated by mass, the coal gangue is 50 parts, the flue gas desulfurization gypsum is 50 parts, the water is 3.5 parts, the polycarboxylic acid high-efficiency water reducing agent is 0.5 parts, and the gypsum plant protein retarder is 0.25 parts.

8. A method for preparing a similar simulation material with low strength and high impact according to claim 1, characterized in that: The method comprises the following steps: (1) Pre-mixing: pre-mix the coal gangue, flue gas desulfurization gypsum, polycarboxylic acid water reducer and gypsum vegetable protein retarder in a mixer for 3 minutes; (2) Add water and stir: slowly add the prepared water into the mixer containing the solid material and stir at a uniform speed to avoid the formation of bubbles and slurry fracture surfaces; (3) Standing: Stir until there are no flocs or bubbles in the slurry, and let it stand for 1 to 2 minutes; (4) Mold filling and curing: The slurry is poured into the test mold and cured in a standard curing box until the initial setting state is reached, and then the mold is removed. The demoulding specimen is cured at room temperature for 14 days to obtain a similar material specimen with low strength and high impact tendency; (5) Mechanical properties test: After 14 days of room temperature curing, the mechanical properties test can be carried out using a testing machine.

9. A method for preparing a similar simulation material with low strength and high impact according to claim 8, characterized in that: The mixer in step (2) is a JJ-5 cement slurry mixer.

10. A method for preparing a similar simulation material with low strength and high impact according to claim 8, characterized in that: The testing machine is an electro-hydraulic servo electronic universal testing machine with a maximum measuring range of 1000KN, a test force measurement accuracy of 0.5%, a sampling frequency of 1000Hz, a displacement measurement accuracy of 0.5%, and a deformation measurement accuracy of 0.5%.

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