A method for maintaining a saturated gravel body in a compressed state

Abstract

The present invention discloses a method for maintaining a saturated crushed stone body in a compressed state, comprising the following steps: (1) immersing the crushed stone for test in water to saturate it; (2) selecting a container for compression test and pouring sol resin slurry into the container; (3) adding the saturated crushed stone in step (1) into the container of step (2); (4) performing a compression test on the crushed stone in step (3) using a movable pressure plate with a plurality of small holes; (5) maintaining the application state of the compressive stress of the movable pressure plate after the test, and removing the applied compressive stress after the sol resin slurry is fully solidified; (6) taking the crushed stone sample maintained in the compressed state out of the container, and using slicing and grinding methods to study the crushing and contact conditions of the crushed stone after compression after sampling; the saturated sample can maintain its compressed state in the experimental state, thereby providing conditions for later sample slicing, modeling, and analysis of its crushing state and the contact relationship between gangue blocks.

Description

Technical Field

[0001] The invention relates to the field of saturated gravel body compression test, and in particular to a method for keeping a saturated gravel body in a compressed state. Background Art

[0002] Crushed stone is often used as filling material. For example, mines often use gangue for filling mining to reduce the amount of surface subsidence. Crushed stone used for filling mining in mines often goes through the process of crushing → filling → compression → soaking. Before adopting the filling mining process, the pre-filled gangue is generally used to carry out the corresponding compression test, and the specific filling process design is carried out based on the test results.

[0003] Conventional shrinkage tests often study the relationship between compressive stress, gangue moisture content, and the size of gangue blocks, which is equal to the amount of compression. At a deeper level, the changes in the crushing state of gangue and the contact relationship between gangue blocks during the compression process are studied. Since gangue is an opaque structure, it is currently impossible to visually observe the changes in the crushing state of gangue and the contact relationship between gangue blocks. The current high-end CT scanning technology is expensive, the scale of the scanned sample is limited, the scanning resolution is relatively low, and its application is severely restricted. How to use a relatively simple method to keep the saturated sample in its compressed state under the experimental state, and provide conditions for later sample slicing, modeling, and analysis of its crushing state and the contact relationship between gangue blocks, has always plagued the development of related experimental research work. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a method for maintaining a saturated gravel body in a compressed state, which can enable the saturated sample to maintain its compressed state under the experimental state, thereby providing conditions for later sample slicing, modeling, and analysis of its crushing state and the contact relationship between gangue blocks.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for maintaining a saturated gravel body in a compressed state, comprising the following steps:

[0007] (1) Saturate the crushed stone for testing with water;

[0008] (2) selecting a container for the compression test, and pouring a sol resin slurry into the container, wherein the flocculation time of the sol resin slurry is greater than the duration of the crushed stone compression test;

[0009] (3) adding the saturated crushed stone in step (1) into the container in step (2), and completely immersing the crushed stone in the sol resin slurry;

[0010] (4) performing a compression test on the crushed stone obtained in step (3) using a movable pressure plate having a plurality of small holes;

[0011] (5) After the test, the compressive stress of the movable platen is maintained, and after the sol resin slurry is fully solidified, the applied compressive stress is removed;

[0012] (6) The compressed gravel sample is taken out of the container and sliced ​​and ground to study the crushing and contact conditions of the compressed gravel.

[0013] Preferably, the diameter of the compression test container selected in step (2) is greater than 5 times the particle size of the gravel used in the test.

[0014] Preferably, during the compression test in step (4), the pressure applied by the movable pressure plate is less than 6 MPa.

[0015] Preferably, in step (4), when performing the compression test, a movable pressure plate is used to perform multiple groups of pressure tests at different pressures.

[0016] Preferably, during the compression test in step (4), the sol resin slurry is always in a flowable state.

[0017] Preferably, the bottom of the container is threadedly connected with a detachable base.

[0018] The beneficial effects of the present invention are:

[0019] The present invention adopts sol resin to maintain the compression state of saturated crushed stone body, which can not only simulate the water in the gaps of crushed stone, but also solidify the compressed crushed stone after the compression test of the crushed stone, and can well maintain the compression state of the saturated crushed stone body, and can provide conditions for later sample slicing, modeling, and analysis of its crushing state and contact relationship between gangue blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the state of the crushed stone of the present invention when it is not compressed;

[0022] Figure 2 It is a schematic diagram of the state of the crushed stone of the present invention when being compressed;

[0023] Figure 3 It is a schematic diagram of the state of the sol resin slurry of the present invention when it solidifies.

[0024] Description of reference numerals:

[0025] 1. Container; 2. Base; 3. Gravel; 4. Sol-resin slurry; 5. Movable pressure plate. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figures 1 to 3 As shown, this embodiment provides a method for maintaining a saturated gravel body in a compressed state.

[0028] (1) Saturate the crushed stone 3 used for the test with water;

[0029] (2) Select a container 1 for compression test, wherein the bottom of the container 1 is threadedly connected with a detachable base 2, and a sol resin slurry 4 is poured into the container 1. The flocculation time of the sol resin slurry 4 is greater than the duration of the crushed stone compression test, and the diameter of the compression test container is greater than 5 times the particle size of the crushed stone used in the test;

[0030] (3) adding the saturated crushed stone 3 in step (1) into the container 1 in step (2), and completely immersing the crushed stone 3 in the sol resin slurry 4;

[0031] (4) using a movable pressure plate 5 with a plurality of small holes to perform a compression test on the crushed stone 3 of step (3), wherein the pressure applied by the movable pressure plate during the compression test is less than 6 MPa, and the movable pressure plate is used to perform multiple groups of pressure tests with different pressures, so that the influence of the pressure on the crushing and contact state of the crushed stone can be analyzed through the test; during the test, the sol resin slurry is always in a flowable state, and a force is applied to the movable pressure plate to perform axial compression during the test, and the crushed stone pieces will be crushed or adjusted in position during the compression, and the sol resin slurry in the gaps between the crushed stones will be discharged from the small holes on the movable pressure plate;

[0032] (5) After the test, the compressive stress of the movable pressure plate 5 is maintained, and after the sol resin slurry 4 is fully solidified, the applied compressive stress is removed;

[0033] (6) Use coring equipment or remove the base of the compression container to take the compressed gravel sample out of the container. After sampling, use slicing and grinding to study the crushing and contact conditions of the compressed gravel.

[0034] The container 1, base 2 and movable pressure plate 5 of this embodiment adopt existing products or structures well known to those skilled in the art, and are connected to each other in an existing connection manner well known to those skilled in the art, which will not be described in detail here.

[0035] The sol resin slurry 4 used in this embodiment is an existing product well known to those skilled in the art. Those skilled in the art can adjust the proportion of the sol resin slurry 4 according to the time of the compression test according to the existing technical method to ensure that the flocculation time of the sol resin slurry 4 is greater than the duration of the gravel compression test.

[0036] Preferably, this embodiment takes a 2-minute compression test as an example. The sol resin slurry 4 of this embodiment is made by mixing liquid A and liquid B, wherein liquid A and liquid B are separately configured and then mixed, and the weight ratio of the liquid A raw material is: modified urea-formaldehyde resin slurry (melamine modified): polyester resin: polyvinyl alcohol = 100:4:1; the weight ratio of the liquid B raw material is: oxalic acid (dilution concentration is 10%-25%): hydrazine carbon sulfamide = 100:5; the weight ratio of liquid A and liquid B is liquid A: liquid B = 10:3 mixture; the test pressure is 1MPA.

[0037] The compression test of this embodiment is conducted using a compression test process well known to those skilled in the art, and will not be described in detail herein.

[0038] Sol resin slurry has the following four advantages: First, the sol resin slurry has a wide adjustable range of solidification time. The slurry can be prepared according to the time required for the test to ensure that the slurry must maintain fluidity within the test time range and does not produce flocculation and solidification. Second, this type of slurry has high consolidation strength. The uniaxial compressive strength of the pure slurry after consolidation can reach more than 6MPa, which can maintain the state of the crushed stone after compression. Third, the slurry has strong permeability. It is generally believed that the slurry can penetrate into the pores that water can penetrate. Fourth, the water content of this type of slurry reaches more than 50%. It can replace pure water during compression to maintain the saturation state of the crushed stone without affecting the compression test results.

[0039] This embodiment uses sol resin to maintain the compression state of the saturated crushed stone body, which can not only simulate the water in the gaps between the crushed stones, but also solidify the compressed crushed stones after the compression test of the crushed stones. It can well maintain the compression state of the saturated crushed stone body and provide conditions for later sample slicing, modeling, and analysis of its crushing state and the contact relationship between the gangue blocks.

[0040] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for maintaining a saturated gravel body in a compressed state, characterized in that: The following steps are involved: (1) Saturate the crushed stone for testing with water; (2) selecting a container for the compression test, and pouring a sol resin slurry into the container, wherein the flocculation time of the sol resin slurry is greater than the duration of the crushed stone compression test; (3) adding the saturated crushed stone in step (1) into the container in step (2), and completely immersing the crushed stone in the sol resin slurry; (4) performing a compression test on the crushed stone obtained in step (3) using a movable pressure plate having a plurality of small holes; (5) After the test, the compressive stress of the movable platen is maintained, and after the sol resin slurry is fully solidified, the applied compressive stress is removed; (6) The compressed gravel sample is taken out of the container and sliced ​​and ground to study the crushing and contact conditions of the compressed gravel.

2. A method for maintaining a saturated gravel body in a compressed state as claimed in claim 1, characterized in that: The diameter of the compression test container selected in step (2) is greater than 5 times the particle size of the crushed stone used in the test.

3. A method for maintaining a saturated gravel body in a compressed state as claimed in claim 1, characterized in that: In step (4), during the compression test, the pressure applied by the movable pressure plate is less than 6 MPa.

4. A method for maintaining a saturated gravel body in a compressed state as claimed in claim 1, characterized in that: In step (4), during the compression test, a movable pressure plate is used to perform multiple groups of pressure tests at different pressures.

5. The method for maintaining a saturated gravel body in a compressed state according to claim 1, characterized in that: During the compression test in step (4), the sol resin slurry is always in a flowable state.

6. A method for maintaining a saturated gravel body in a compressed state as claimed in claim 1, characterized in that: The bottom of the container is threadedly connected with a detachable base.

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