Test device and method for testing and sampling discharge rate of coal mining slurry

Abstract

The present application relates to the technical field of filling coal mining, and particularly relates to a filling coal mining slurry bleeding rate testing and sample preparation test device and test method. The device comprises: a constraint cylinder, the side wall of which is a hollow structure; a flexible bleeding unit, which is attached to the inner side wall of the constraint cylinder; an inner lining structure, which is attached to the inner side wall of the flexible bleeding unit, and the inner lining structure is provided with a plurality of support platforms along the height direction; and a plurality of sample molds, which are arranged on the support platforms. The present application can simultaneously meet the needs of filling coal mining slurry bleeding rate testing and filling coal mining slurry standard sample preparation, effectively avoid the problems of sample height reduction and size not meeting the standards caused by water loss, accurately control the slurry form, ensure the formation of standard samples, and truly reflect the actual mechanical properties of the filling body. The sample height change before and after the slurry bleeding can be recorded in real time, and the volume of the slurry in the actual filling process can be quickly calculated.

Description

Technical Field

[0001] This invention relates to the field of backfilling coal mining technology, and in particular to a test apparatus and test method for testing and preparing samples of backfilling coal slurry bleeding rate. Background Technology

[0002] In the field of coal backfilling technology, high water-ash ratio weak cementitious backfill slurry, due to its excellent flow properties resulting from high water content, can quickly and uniformly fill goaf areas, effectively solving engineering problems such as goaf roof support and surface subsidence control. It has become one of the important materials for mine backfilling in recent years. The core application logic of this type of slurry lies in: utilizing high water content to reduce slurry viscosity to ensure efficient transport and diffusion; after being filled into the goaf, excess water is naturally excreted through a matching flexible template bag; and then, relying on the hydration reaction of the cementitious material, a backfill body with a certain strength is formed, ultimately achieving stable support for the goaf. However, the material characteristics of a high water-ash ratio also bring significant technical bottlenecks to the performance testing and standard sample preparation of the slurry, specifically in the following three aspects: Firstly, the preparation of standard specimens is difficult and fails to meet testing specifications. According to relevant standards for filling strength testing, standard specimens with uniform dimensions (e.g., Φ50mm×100mm or 100mm×100mm) are required to ensure the comparability of strength data. However, high water-cement ratio weak-cement filling slurries typically have a water content exceeding 60%. During specimen molding, moisture easily escapes through mold gaps or the slurry's own pores, leading to specimen shrinkage and reduced height, failing to meet the dimensional requirements of standard specimens. Even if molding is forced, the shrunken specimens are prone to cracking, delamination, and other defects, directly affecting the effectiveness of strength testing.

[0003] Secondly, the uneven bleeding process of the slurry leads to large dispersion in sample strength. When high water-cement ratio slurry bleeds inside the flexible formwork bag, the water migrates mainly from top to bottom and is discharged from the bottom or sides of the formwork bag due to gravity. This causes solid particles (such as cement and aggregate) in the slurry to accumulate in the lower part under the influence of gravity settling, resulting in a significantly higher density in the lower part of the slurry than in the upper part. This difference in density between the upper and lower parts directly translates into a difference in strength. Some test data show that the strength of the lower part of the same batch of samples can be 1.5-2 times that of the upper part. As a result, the strength values ​​obtained by testing cannot truly reflect the actual mechanical properties of the filling body, posing a hidden danger to the safety and economy of goaf support design.

[0004] Third, existing testing equipment is functionally limited and cannot simultaneously meet the needs of bleeding rate testing and standard sample preparation. Current devices for testing the performance of high water-cement ratio slurries are mostly designed for a single function: one type of device simply collects the bleed water through a container and calculates the bleeding rate, but cannot simulate the constrained environment of a flexible template bag, nor can it simultaneously prepare standard samples. Another type of device, while suitable for sample molding, does not consider the impact of the bleeding process on sample size and uniformity, requiring additional bleeding rate testing. This is not only cumbersome and time-consuming, but also prone to poor data correlation due to differences in testing environments. This fragmented functionality makes it difficult to meet the integrated testing needs of high water-cement ratio weak cementitious filling slurries from performance evaluation to engineering applications, thus hindering the promotion and optimization of such materials in the field of coal filling.

[0005] In summary, given the technical challenges in standard sample preparation, bleeding rate and filling rate prediction, and functional integration of testing devices for high water-cement ratio weak adhesive filling slurries, there is an urgent need to develop a testing device that can simultaneously simulate bleeding using flexible template bags, accurately test the bleeding rate, and ensure the quality of standard sample molding. This device would provide reliable experimental technical support for the performance optimization and engineering application of high water-cement ratio filling materials. Summary of the Invention

[0006] This invention provides a test apparatus and test method for testing and preparing samples of backfill coal slurry, which solves the defects of the prior art that the sample height is reduced, the size does not meet the standard, and the strength difference between the upper and lower parts of the sample is significant due to water loss, and cannot meet the requirements of both water loss testing and standard sample preparation.

[0007] This invention provides a test apparatus for testing and preparing samples of the bleeding rate of backfill coal slurry, comprising: The constraint tube has a hollowed-out side wall structure. A flexible water-draining unit is attached to the inner wall of the constraint cylinder; The inner lining structure is attached to the inner wall of the flexible water-bleeding unit, and the inner lining structure is provided with multiple support platforms along the height direction; Multiple sample molds are provided on the support platform for filling samples.

[0008] According to the experimental apparatus for testing and preparing samples of backfill coal slurry bleeding rate provided by the present invention, the flexible bleeding unit includes: Multiple flexible water-permeable fabrics are spliced ​​together to form a receiving cavity with an open top surface, closed side walls, and a closed bottom surface, the receiving cavity being used to fill the filling slurry.

[0009] According to the experimental apparatus for testing and preparing samples of backfilled coal slurry bleeding rate provided by the present invention, the inner lining structure includes: The inner lining skeleton extends along the height direction of the constraint cylinder and is attached to the inner sidewall of the flexible water-draining unit. Multiple support platforms are evenly spaced along the height direction of the inner lining skeleton.

[0010] According to the experimental apparatus for testing and preparing samples of the bleeding rate of backfilled coal slurry provided by the present invention, the inner lining skeleton includes: Multiple support rods extend along the height direction of the constraint cylinder, and the multiple support rods are evenly spaced around the circumference of the constraint cylinder.

[0011] According to the experimental apparatus for testing and preparing samples of backfilled coal slurry bleeding rate provided by the present invention, each of the support platforms includes: The first horizontal annular member is equipped with a top hoop; The second horizontal annular rod is located below the first horizontal annular rod, and the second horizontal annular rod is provided with a bottom hoop. The top hoop and the bottom hoop cooperate to position the sample mold.

[0012] According to the test apparatus for testing and preparing samples of the bleeding rate of filling coal slurry provided by the present invention, both the top hoop and the bottom hoop are elastic frame structures, and the bottom hoop is provided with a boss, which is used to insert and cooperate with the cut opening at the bottom of the sample mold.

[0013] According to the experimental apparatus for testing and preparing samples of backfilled coal slurry bleeding rate provided by the present invention, the sample mold includes: The bottom edge has a hollow structure; The side has a hollow structure and is inserted into the bottom edge.

[0014] According to the test apparatus for testing and sample preparation of the bleeding rate of backfilled coal slurry provided by the present invention, the edge of the bottom side forms a protrusion; The side includes: Multiple side units are spliced ​​together and inserted into the inner side of the edge.

[0015] This invention also provides a method for testing the bleeding rate of backfill coal slurry, comprising: Record the first mass and the first height of the constraint cylinder of the test apparatus for testing and preparing the bleeding rate of backfilled coal slurry, as described in the present invention, when the backfilled slurry is not filled. The prepared filling slurry is injected into the test device for testing and preparing the bleeding rate of the filling coal slurry. After filling, the second mass of the injected filling slurry is recorded. After the bleeding process is completed, record the third mass and the second height of the filling material in the test apparatus; The water leakage rate of the flexible water leakage unit is determined based on the first mass, the second mass, and the third mass. The fill rate is determined based on the first and second heights.

[0016] This invention also provides a method for preparing standard samples of filling coal slurry, comprising: After the filling slurry is injected into the test device for testing and preparing the bleeding rate of the filling coal mining slurry as described in this invention, after the bleeding ends and the slurry stabilizes, the constraint cylinder and the flexible bleeding unit are removed, the filling material around the sample is peeled off, the excess filling material is scraped off along the periphery of the sample mold, the top is flattened and the sample mold is removed, and the standard sample is obtained by removing the sample mold. The actual strength value of the filling material is determined by averaging the strengths of multiple standard specimens located at different heights.

[0017] This invention provides a test apparatus and method for testing and preparing samples of the bleeding rate of backfilled coal slurry. It simultaneously meets the needs of testing the bleeding rate of backfilled coal slurry and preparing standard samples. It can precisely control the morphology and volume shrinkage of high water-cement ratio weak cementitious backfilled slurry during the bleeding process, effectively avoiding problems such as reduced sample height and substandard dimensions due to water loss. It effectively solves the problem of preparing standard samples for high water-cement ratio slurry, ensuring the standardization of strength testing. By setting a sample mold, the slurry morphology can be precisely controlled, ensuring the formation of standard samples. Furthermore, by taking the average value of multiple samples, the strength dispersion is significantly reduced, accurately reflecting the actual mechanical properties of the backfill body and providing reliable data support for the safety and economy of goaf support design. It can record the sample height change before and after slurry bleeding in real time. Based on this height data and combined with the actual filling space parameters of the goaf, the volume of the slurry during the actual filling process can be quickly calculated, thereby predicting the slurry filling rate and further improving the construction quality and safety assurance level of backfilled coal mining projects. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the experimental device for testing and preparing samples of the bleeding rate of backfilled coal slurry provided in one embodiment of the present invention.

[0020] Figure 2 This is a cross-sectional view of the test apparatus for testing and preparing samples of the bleeding rate of backfilled coal slurry provided in one embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the structure of the constraint cylinder provided in one embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of a flexible water-secreting unit provided in one embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the lining structure and sample mold provided in one embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the support rod and support platform provided in one embodiment of the present invention.

[0025] Figure 7 This is a disassembly diagram of a sample mold provided in one embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of the testing and sample preparation process of the experimental device for testing and preparing the bleeding rate of backfilled coal slurry provided in one embodiment of the present invention.

[0027] Figure label: 1. Constraint tube; 2. Flexible drainage unit; 3. Lining structure; 311. Support rod; 321. First horizontal ring rod; 322. Top hoop; 331. Second horizontal ring rod; 332. Bottom hoop; 333. Boss; 4. Sample mold; 410. Bottom edge; 411. Cut opening; 421. Side unit. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] In the description of this embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this embodiment.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this embodiment, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this embodiment, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0032] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] The following is combined Figures 1-8 This invention describes a test apparatus for testing and preparing samples of the bleeding rate of backfilled coal slurry. The apparatus includes: a constraint cylinder 1, a flexible bleeding unit 2, an inner lining structure 3, and multiple sample molds 4.

[0034] The constraint cylinder 1 has a hollowed-out side wall; the flexible water-bleeding unit 2 is attached to the inner side wall of the constraint cylinder 1; the inner lining structure 3 is attached to the inner side wall of the flexible water-bleeding unit 2, and the inner lining structure 3 has multiple support platforms along the height direction; multiple sample molds 4 are set on the support platforms for filling samples.

[0035] Specifically, the constraint cylinder 1 can be a cylindrical structure. The constraint cylinder 1 is preferably a metal cylindrical cylinder with a hollow structure on its side wall. The top and bottom surfaces are connected and there is no constraint surface. The constraint cylinder 1 only serves to block the slurry and shape it. The exuded water can be discharged from the hollow structure of the constraint cylinder 1.

[0036] Specifically, the flexible water-bleeding unit 2 is a water-bleeding material used to fill the coal mining face. It can expel excess water from the filling slurry but retain the slurry components without expelling them, thus achieving high water-cement ratio transportation and low water-cement ratio hydration reaction, resulting in a rapid increase in the strength of the filling body. Because the flexible water-bleeding unit 2 is made of flexible water-bleeding material, it can be attached and fixed to the inner wall of the constraint cylinder 1.

[0037] Specifically, the inner lining structure 3 is located inside the flexible bleeding unit 2, providing internal support for the flexible bleeding unit 2 and also having multiple support platforms on it. The flexible bleeding unit 2 is internally positioned by the inner lining structure 3 and externally positioned by the constraint cylinder 1, thereby limiting the flexible bleeding unit 2 and maintaining its basic shape. Preferably, three support platforms are set along the height direction on the inner lining structure 3, corresponding to upper, middle, and lower sample molds 4. Due to the bleeding effect of the filling slurry, the density inside the constraint cylinder 1 is higher at the bottom and lower at the top. Therefore, setting three sample molds 4 and taking the average strength value of the prepared samples as the average of the three samples significantly reduces the strength dispersion and can truly reflect the actual mechanical properties of the filling body, providing reliable data support for the safety and economy of goaf support design.

[0038] It should be understood that the number of support platforms and sample molds 4 is the same, with one sample mold 4 set on each support platform. Depending on the actual situation, other numbers of support platforms and sample molds 4 can also be set.

[0039] Specifically, the sample mold 4 can be a cubic or cylindrical structure, and the sample mold 4 is processed to correspond to the shape of the standard sample as needed. Through the specific shape of the sample mold 4, the slurry shape can be precisely controlled and the standard sample can be formed.

[0040] The experimental apparatus for testing and preparing samples of backfilled coal slurry according to the present invention can be used for testing the bleeding rate of backfilled coal slurry and preparing standard samples of backfilled coal slurry.

[0041] The test for the bleeding rate of backfill coal slurry includes: S101. Record the first mass of the device when it is not filled with filling slurry and the first height of the constraint cylinder 1; S102. Inject the prepared filling slurry into this device. After filling, record the second mass of the injected filling slurry. S103. After the bleeding is completed, record the third mass and the second height of the filling material in the test device; S104. Determine the water leakage rate of the flexible water leakage unit 2 based on the first mass, the second mass, and the third mass; S105. Determine the filling rate based on the first and second heights.

[0042] The standard sample preparation methods for filling coal slurry include: S201. After injecting the filling slurry into this device, wait for the bleeding to stop and the slurry to stabilize, remove the constraint cylinder 1 and the flexible bleeding unit 2, peel off the filling material around the sample, scrape off the excess filling material around the sample mold 4, scrape the top flat and take out the sample mold 4, and remove the sample mold 4 to obtain the standard sample. S202 takes the average strength of multiple standard specimens located at different heights to determine the actual strength value of the filling material.

[0043] As can be seen, the experimental device for testing and preparing samples of backfill slurry provided by this invention can simultaneously meet the needs of testing the bleeding rate of backfill slurry and preparing standard samples of backfill slurry. It can accurately control the morphology and volume shrinkage of high water-ash ratio weak cementitious backfill slurry during the bleeding process, effectively avoiding the problems of reduced sample height and substandard size caused by water loss. It effectively solves the problem of preparing standard samples of high water-ash ratio slurry and ensures the standardization of strength testing. By setting the sample mold 4, the slurry morphology can be accurately controlled and the standard sample can be formed. By taking the average value of multiple samples, the strength dispersion can be significantly reduced, which can truly reflect the actual mechanical properties of the backfill body and provide reliable data support for the safety and economy of goaf support design. It can record the sample height change before and after slurry bleeding in real time. Based on this height data and combined with the actual filling space parameters of the goaf, the volume of slurry during the actual filling process can be quickly calculated, thereby predicting the slurry filling rate and further improving the construction quality and safety assurance level of backfill mining engineering.

[0044] In one embodiment of the present invention, the flexible water-permeable unit 2 includes multiple flexible water-permeable fabrics. These fabrics are spliced ​​together to form a receiving cavity with an open top surface, closed side walls, and a closed bottom surface. The receiving cavity is used to fill the cavity with slurry. Specifically, the flexible water-permeable fabrics are spliced ​​together and adhered to the inner surface of the constraint cylinder 1, arranged flat, with an open top surface and a sealed bottom surface, forming a receiving cavity with an open top surface, through which slurry can be injected.

[0045] In one embodiment of the present invention, the inner lining structure 3 includes: an inner lining skeleton extending along the height direction of the constraint cylinder 1 and attached to the inner sidewall of the flexible water-bleeding unit 2, and a plurality of support platforms evenly spaced along the height direction of the inner lining skeleton. Specifically, the inner lining skeleton is disposed close to the inner side of the flexible water-bleeding unit 2, maintaining the basic shape of the flexible water-bleeding unit 2, and providing support and installation positions for the support platforms.

[0046] In one embodiment of the present invention, the inner lining skeleton includes: a plurality of support rods 311 extending along the height direction of the constraint cylinder 1, and the plurality of support rods 311 being evenly spaced around the circumference of the constraint cylinder 1. Specifically, the support rods 311 are made of rigid plastic rods or rust-proof metal rods, preferably four support rods 311 arranged at intervals to form the inner lining skeleton, and the support platform is horizontally supported on the four support rods 311.

[0047] In one embodiment of the present invention, each support platform includes: a first horizontal annular rod 321 and a second horizontal annular rod 331. The first horizontal annular rod 321 is provided with a top hoop 322; the second horizontal annular rod 331 is located below the first horizontal annular rod 321 and is provided with a bottom hoop 332. The top hoop 322 and the bottom hoop 332 cooperate to position the sample mold 4. Specifically, the support platform is composed of the upper first horizontal annular rod 321 and the lower second horizontal annular rod 331. The first horizontal annular rod 321 is provided with a top hoop 322, and the second horizontal annular rod 331 is provided with a bottom hoop 332. The top hoop 322 constrains the top end of the sample mold 4, and the bottom hoop 332 constrains the bottom end of the sample mold 4, thereby realizing the positioning of the sample mold 4.

[0048] In one embodiment of the present invention, both the top hoop 322 and the bottom hoop 332 are elastic frame structures, and the bottom hoop 332 is provided with a boss 333, which is used to engage with the slit 411 at the bottom of the sample mold 4. Specifically, the edge of the bottom hoop 332 protrudes upward at the middle position to form a boss 333, which serves to constrain the sample mold 4 on the one hand, and on the other hand, the boss 333 can be inserted into the slit 411 at the bottom of the sample mold 4, facilitating the installation and removal of the sample mold 4.

[0049] In one embodiment of the present invention, the sample mold 4 includes a bottom edge 410 and a side edge. The bottom edge 410 has a hollow structure; the side edge has a hollow structure and is inserted into the bottom edge 410. Specifically, the sample mold 4 is a mold with a top opening and hollow structures on the side edge and bottom edge 410, and its material is rigid plastic.

[0050] In one embodiment of the present invention, the edge of the bottom edge 410 is formed with a protrusion; the side edge includes a plurality of side edge units 421, which are spliced ​​together and inserted into the inner side of the edge. Taking a cubic mold as an example, its side edge is formed by splicing two adjacent side edge units 421; the bottom edge 410 is hollowed out and the edge protrudes upward, which serves to constrain the side edge. Two side edge units 421 are spliced ​​together to form a side edge, which is then inserted into the bottom edge 410 to form a cubic mold. The bottom edge 410 is provided with a slit 411 along the bottom edge, which is inserted and engaged with the boss 333 of the bottom hoop 332; the top hoop 322 constrains the upper edge of the sample mold 4, forming a stable connected whole.

[0051] Of course, a cylindrical mold can also be used depending on the requirements of the standard sample shape.

[0052] This invention also provides a method for testing the bleeding rate of backfill coal slurry, comprising: S101. Record the first mass of the test device for testing and preparing samples of the backfilled coal slurry bleeding rate in the above embodiments of the present invention when the backfilled slurry is not filled and the first height of the constraint cylinder. S102. The prepared filling slurry is injected into the test device for testing and preparing the bleeding rate of the filling coal mining slurry in the above embodiment of the present invention. After filling, the second mass of the injected filling slurry is recorded. After the S103 bleeds, record the third mass and the second height of the filling material in the test apparatus. S104. Determine the water leakage rate of the flexible water leakage unit based on the first mass, the second mass, and the third mass; S105. Determine the filling rate based on the first and second heights.

[0053] The specific testing method is as follows: The prepared high water-cement ratio filling slurry is injected into the test device until the entire device is filled. The weight of the filling slurry injected into the device is weighed, and the weight of the filling slurry is M. The total weight of the device before the slurry is injected is M0. After the bleeding is completed, the total weight of the device and the slurry is weighed, and this weight is m. Under the conditions of this filling slurry, the bleeding rate of the flexible template fabric is... for: Simultaneously, the remaining height of the filling material inside the constraint cylinder after the bleeding was completed was measured as h1, and the total height of the constraint cylinder was h2. Since the slurry height was the same as the constraint cylinder height after the cylinder was filled, h2 was numerically equal to the height of the filled cylinder. Therefore, the filling rate... for: The filling effect of goaf can be predicted.

[0054] This invention also provides a method for preparing standard samples of filling coal slurry, comprising: S201. After injecting the filling slurry into the test device for testing and preparing the bleeding rate of the filling coal mining slurry in the above embodiment of the present invention, after the bleeding ends and the slurry stabilizes, remove the constraint cylinder and the flexible bleeding unit, peel off the filling material around the sample, scrape off the excess filling material around the sample mold, flatten the top and take out the sample mold, and remove the sample mold to obtain the standard sample. S202. Take the average strength of multiple standard specimens located at different heights to determine the actual strength value of the filling material.

[0055] The specific sample preparation method is as follows: The filling slurry is injected into the device, submerging the mold support platform. The hollow mold surface cannot stop the movement of the flowing slurry. After stabilization, the filling material reaches a plastic state. The constraint cylinder and flexible water-bleeding unit are removed, the filling material around the sample is peeled off, and the excess filling material is scraped off along the mold. After the top is leveled, the sample mold is removed. Then the sides and bottom of the mold are removed to form a standard sample.

[0056] Due to the bleeding effect of the filling slurry, the density inside the confining cylinder is higher at the bottom and lower at the top. Therefore, the average strength of the three standard samples taken from the top, middle and bottom is taken as the actual strength value of the filling body.

[0057] In summary, this invention provides a testing device and method that can precisely control the slurry morphology and ensure the formation of standard samples, solving the problem of preparing standard samples for high water-cement ratio slurries; it addresses the issue of water loss from top to bottom during the bleeding process of high water-cement ratio weak adhesive filling slurries, resulting in higher density at the bottom of the slurry and significant differences in strength between the upper and lower parts of the sample. By optimizing the device structure, uniform density distribution during the bleeding process is achieved, reducing sample strength dispersion and improving the accuracy and reliability of slurry strength test results; it enables efficient and accurate testing of the bleeding rate of high water-cement ratio weak adhesive filling slurries under simulated working conditions in flexible template bags, simultaneously meeting the dual needs of slurry bleeding performance testing and standard sample preparation. This provides reliable experimental data support for the proportion optimization of high water-cement ratio weak adhesive filling slurries and the adjustment of on-site construction parameters for coal filling, filling the technical gap where existing devices cannot simultaneously handle bleeding rate testing and standard sample preparation.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A test apparatus for testing and preparing samples of the bleeding rate of backfilled coal slurry, characterized in that, include: The constraint tube (1) has a hollowed-out side wall; The flexible water-draining unit (2) is attached to the inner wall of the constraint cylinder (1); The inner lining structure (3) is attached to the inner wall of the flexible water-bleeding unit (2), and the inner lining structure (3) is provided with multiple support platforms along the height direction; Multiple sample molds (4) are provided on the support platform for filling samples.

2. The experimental apparatus for testing and preparing samples of the bleeding rate of backfilled coal slurry according to claim 1, characterized in that, The flexible water-secreting unit (2) includes: Multiple flexible water-permeable fabrics are spliced ​​together to form a receiving cavity with an open top surface, closed side walls, and a closed bottom surface, the receiving cavity being used to fill the filling slurry.

3. The test device for testing and sampling the discharge rate of a coal filling slurry according to claim 1, characterized in that, The inner lining structure (3) includes: The inner lining skeleton extends along the height direction of the constraint cylinder (1) and is attached to the inner side wall of the flexible water-bleeding unit (2). Multiple support platforms are evenly spaced along the height direction of the inner lining skeleton.

4. The test apparatus for testing and sampling the discharge rate of a coal filling slurry according to claim 3, characterized in that, The inner lining skeleton includes: Multiple support rods (311) extend along the height direction of the constraint cylinder (1), and the multiple support rods (311) are evenly spaced around the circumference of the constraint cylinder (1).

5. The test device for testing and sampling the discharge rate of a coal filling slurry according to claim 1, characterized in that, Each of the aforementioned support platforms includes: The first horizontal annular member (321) is provided with a top hoop (322); The second horizontal ring rod (331) is located below the first horizontal ring rod (321), and the second horizontal ring rod (331) is provided with a bottom hoop (332). The top hoop (322) and the bottom hoop (332) cooperate to position the sample mold (4).

6. The test apparatus for testing and sampling the discharge rate of a coal filling slurry according to claim 5, characterized in that, Both the top hoop (322) and the bottom hoop (332) are elastic frame structures, and the bottom hoop (332) is provided with a boss (333), which is used to insert and cooperate with the cut opening (411) at the bottom of the sample mold (4).

7. The test device for testing and sampling the discharge rate of a backfilling coal slurry according to any one of claims 1 to 6, characterized in that, The sample mold (4) includes: The bottom edge (410) is a hollow structure; The side has a hollow structure and is inserted into the bottom edge (410).

8. The experimental apparatus for testing and preparing samples of the bleeding rate of backfilled coal slurry according to claim 7, characterized in that, The edge of the bottom edge (410) forms a protrusion; The side includes: Multiple side units (421) are spliced ​​together and inserted into the inner side of the edge.

9. A method for testing the bleeding rate of backfill coal slurry, characterized in that, include: Record the first mass and the first height of the constraint cylinder of the test apparatus for testing and preparing the bleeding rate of backfilled coal slurry as described in any one of claims 1 to 8 when it is not filled with backfilled slurry. The prepared filling slurry is injected into the test device for testing and preparing the bleeding rate of the filling coal slurry. After filling, the second mass of the injected filling slurry is recorded. After the bleeding process is completed, record the third mass and the second height of the filling material in the test apparatus; The water leakage rate of the flexible water leakage unit is determined based on the first mass, the second mass, and the third mass. The fill rate is determined based on the first and second heights.

10. A method of standard sampling of a coal mining backfill slurry, characterized by, include: After injecting the filling slurry into the test device for testing and preparing the bleeding rate of the filling coal mining slurry as described in any one of claims 1 to 8, after the bleeding ends and the slurry stabilizes, remove the constraint cylinder and the flexible bleeding unit, peel off the filling material around the sample, scrape off the excess filling material around the sample mold, flatten the top and take out the sample mold, and remove the sample mold to obtain a standard sample. The actual strength value of the filling material is determined by averaging the strengths of multiple standard specimens located at different heights.

Images