A test device for large-size filled false roof under compression deformation and failure under prestressed conditions

Abstract

The present invention relates to the field of mining engineering filling body sample preparation and experimental technology, and in particular to a large-size filling false roof compression deformation failure test device under prestressed conditions, including a base plate, a mold, a horizontal stretching mechanism, a normal pressure mechanism and a data acquisition system; the mold is a hollow rectangular parallelepiped structure, which is correspondingly fixed to the middle of the upper end surface of the base plate, and a number of steel bar holes are evenly distributed on the surrounding side walls; the horizontal stretching mechanism is provided with two groups, which are respectively distributed on the outside of the mold side wall, and the two groups of horizontal stretching mechanisms are perpendicular to each other, and the bottom of the horizontal stretching mechanism is fixed to the base plate; the normal pressure mechanism is arranged between the upper and lower sides of the mold; the data acquisition system is respectively connected to the horizontal stretching mechanism and the normal pressure mechanism. The present invention is not only easy to operate, complete in structure, and can independently complete the test, but also can adjust the prestress applied to the steel bar, and the size is closer to the actual site, which has important reference significance for actual engineering operations.

Description

Technical Field

[0001] The invention relates to the field of mining engineering filling body sample preparation and experimental technology, in particular to a large-size filling false roof compression deformation and destruction test device under prestressed conditions. Background Art

[0002] With the development of mining engineering technology, underground mining technology has become increasingly mature. As a new type of mining method, the downward layered filling mining method has high safety and economy. It is suitable for various types of deposits, especially in areas with complex geological conditions and unstable rock mass, and has good application prospects. As an important factor in the downward layered filling mining method, the filling false roof is of great significance to the safety of on-site construction by studying its deformation law and stability evaluation during the compression process.

[0003] In the traditional test device for simulating the compression deformation of the filled false roof, in order to facilitate the experimental operation, the filling body sample is reduced by a larger ratio than the filled false roof to be simulated, usually 1:10, and the sample size is usually around 10mm, resulting in the filling body sample being smaller than the actual size; at the same time, the steel bars used are reduced in proportion and generally replaced by thin iron wires, but their mechanical properties and morphological characteristics are significantly different from the steel bars actually used on site. Therefore, the strength data of the filled false roof obtained by the traditional test for simulating the compression deformation of the filled false roof does not match the on-site strength, and there is a large error.

[0004] At present, the exposed steel bars of the samples made to study the strength of the filling false roof are only fixed at the ends, and the specific prestress applied cannot be controlled, so it is impossible to determine the effect of applying different prestresses to the steel bars on the strength of the filling false roof. Therefore, the strength data obtained from the traditional test simulating the compression deformation of the filling false roof is difficult to accurately represent the true strength of the in-situ filling false roof underground. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a large-size filled false roof compressive deformation failure test device under prestressed conditions, which can effectively solve the problem that the size of the filled false roof specimen is too small, resulting in a large difference between its mechanical properties and the actual situation on site, and at the same time can determine the influence of applying different prestresses to the steel bars on the strength of the filled false roof.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention proposes a large-size filled false roof compressive deformation and destruction test device under prestressed conditions, comprising a base plate, a mold, a horizontal stretching mechanism, a normal pressurizing mechanism and a data acquisition system; the mold is a hollow rectangular structure, which is fixed to the middle of the upper end surface of the base plate, and a number of steel bar holes are evenly distributed on the surrounding side walls; the horizontal stretching mechanism is provided with two groups, which are respectively distributed on the outside of the mold side walls, and the two groups of horizontal stretching mechanisms are perpendicular to each other, and the bottoms of the horizontal stretching mechanisms are fixed to the base plate; the normal pressurizing mechanism is arranged between the upper and lower sides of the mold; the data acquisition system is respectively connected to the horizontal stretching mechanism and the normal pressurizing mechanism.

[0008] Furthermore, the horizontal stretching mechanism includes two horizontal reaction force frames, a steel bar stretching cylinder, and a steel bar locking clamp; the two horizontal reaction force frames are respectively arranged on the outside of a group of opposite side walls of the mold, and the horizontal reaction force frames and their corresponding mold side walls are parallel to each other and vertically fixed to the bottom plate; the cylinder body of the steel bar stretching cylinder is vertically fixed to the middle and upper part of the horizontal reaction force frame on one side and its piston rod end corresponds to the mold side wall; the steel bar locking clamp is fixed to the piston rod end of the steel bar stretching cylinder, and a clamping hole corresponding to the steel bar hole is provided on the end face of the steel bar locking clamp corresponding to the mold side wall; and a fixing hole corresponding to the steel bar hole is opened on the surface of the horizontal reaction force frame on the other side.

[0009] Furthermore, two outer ends of the horizontal reaction force frame are fixedly connected to the bottom plate through triangular steel plates.

[0010] Furthermore, in each set of horizontal stretching mechanisms, two ends of two horizontal reaction force frames outside a set of side walls of the mold are fixedly connected by support rods.

[0011] Furthermore, a loading oil pump, an unloading oil valve, a pressure gauge and a pressure sensor are arranged between the steel bar stretching cylinder and the data acquisition system; the loading oil pump, unloading oil valve, pressure gauge and pressure sensor are connected in sequence and then connected to the data acquisition system via the pressure sensor; the steel bar stretching cylinder is connected to the line between the unloading oil valve and the pressure gauge.

[0012] Furthermore, the outer side of the mold is fixedly connected to the bottom plate via a fixed wall.

[0013] Furthermore, the mold side wall is a solid steel structure.

[0014] Furthermore, the normal pressurizing mechanism includes a normal reaction force frame, a normal loading cylinder, a loading block and a four-point compression component; the normal reaction force frame is horizontally arranged on the upper and lower sides of the mold, and the four corners of the normal reaction force frames on the upper and lower sides of the mold are fixedly connected by pillars; the normal loading cylinder is arranged above the lower normal reaction force frame; the loading blocks are correspondingly arranged on the upper and lower sides of the mold, and the upper loading block is connected to the upper normal reaction force frame, and the lower loading block is connected to the output end of the normal loading cylinder; the four-point compression component is four round iron rods with the same length as the sample, two of which are arranged in parallel between the mold and the lower loading block, and the other two are arranged in parallel between the mold and the upper loading block, and the two ends of the two round iron rods on the same side are fixed by iron sheets.

[0015] Furthermore, the normal loading cylinder is connected to the data acquisition system through a normal hydraulic servo system.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention proposes a large-size filling false roof compression deformation failure test device under prestressed conditions. The steel bars of the filling false roof specimen are prestressed by the steel bar stretching cylinder and the steel bar locking clamp. The whole device is simple to assemble and easy to operate, which overcomes the disadvantage that the traditional filling false roof mold test device cannot control the prestress applied to the steel bars. Moreover, the present invention is easy to operate, has a complete structure, can independently complete the test, and can adjust the prestress applied to the steel bars. The size is closer to the actual site, which has important reference significance for actual projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of a large-size filled false roof compression deformation failure test device under prestress conditions proposed by the present invention;

[0019] Figure 2 yes Figure 1 A schematic diagram of the main structure of the middle horizontal stretching mechanism and the normal pressurizing mechanism;

[0020] Figure 3 yes Figure 1 A schematic diagram of the top view of the structure of the middle horizontal stretching mechanism and the normal pressurizing mechanism;

[0021] Figure 4 It is a structural diagram of the mold and the steel mesh;

[0022] Figure 5 It is a schematic diagram of the structure of the specimen and the four-point compression component;

[0023] Figure 6 It is a schematic diagram of the clamping holes of the steel bar locking clamp.

[0024] Among them, the figure markings are: 1-rebar; 2-Y side plate; 3-X side plate; 4-bottom plate; 5-sample; 6-four-point compression component; 7-upper loading block; 8-lower loading block; 9-normal loading cylinder; 10-normal reaction frame; 11-rebar locking clamp; 12-horizontal reaction frame; 13-rebar stretching cylinder; 14-unloading oil valve; 15-loading oil pump; 16-pressure gauge; 17-pressure sensor; 18-normal hydraulic servo system; 19-data acquisition system; 20-rebar hole; 21-clamping hole; 22-triangular steel plate; 23-fixed wall; 24-support rod; 25-pillar. DETAILED DESCRIPTION

[0025] 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 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.

[0026] It should be noted that, in the description of the present invention, the terms "up", "down", "top", "bottom", "one side", "the other side", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device or element must have a specific orientation, be constructed and operated in a specific orientation.

[0027] See attached Figure 1-6 The specific structure of an embodiment of a large-size filling false roof compression deformation failure test device under prestressed conditions proposed by the present invention is given. The device includes a bottom plate 4, a mold, a horizontal stretching mechanism, a normal pressurizing mechanism and a data acquisition system 19.

[0028] The mold is a hollow rectangular parallelepiped structure, which is composed of two Y side panels 2 and two X side panels 3 connected in sequence, and the lengths of the Y side panels 2 and the X side panels 3 are equal, and both are solid steel structures. The outer side of the mold is fixed to the middle of the upper end surface of the bottom plate 4 through a fixed wall 23, and a number of steel bar holes 20 are evenly distributed on the side walls around the mold; the normal pressure mechanism is arranged between the upper and lower sides of the mold; the data acquisition system 19 is respectively connected to the horizontal stretching mechanism and the normal pressure mechanism, and is also connected to a computer.

[0029] In this embodiment, there are two groups of horizontal stretching mechanisms, one of which is arranged between the outside of one group of opposite side walls of the mold, and the other is arranged between the outside of another group of opposite side walls of the mold. The two groups of horizontal stretching mechanisms are arranged vertically to each other, and the bottoms are fixedly connected to the bottom plate 4.

[0030] Specifically, the horizontal stretching mechanism includes two horizontal reaction force frames 12, a steel bar stretching cylinder 13 and a steel bar locking clamp 11; the two horizontal reaction force frames 12 are respectively arranged outside a set of opposite side walls of the mold and are parallel to the corresponding mold side walls, and the bottom of the horizontal reaction force frame 12 is vertically fixedly connected to the bottom plate 4 in a detachable manner; the cylinder body of the steel bar stretching cylinder 13 is vertically fixedly connected to the middle and upper part of one side of the horizontal reaction force frame 12 through a flange and its piston rod end corresponds to the mold side wall; the steel bar locking clamp 11 is fixedly connected to the piston rod end of the steel bar stretching cylinder 13, and a clamping hole 21 corresponding to the steel bar hole 20 is arranged on the end surface of the steel bar locking clamp 11 corresponding to the mold side wall; the surface of the horizontal reaction force frame 12 on the other side is provided with a fixing hole corresponding to the steel bar hole 20. Among them, the two ends of the outer side of the horizontal reaction force frame 12 are fixedly connected to the bottom plate 4 through triangular steel plates 22. In each set of horizontal stretching mechanisms, the two ends of the two horizontal reaction force frames 12 outside a set of side walls of the mold are fixedly connected by support rods 24. The function of the support rods 24 is to maintain the stability of the horizontal reaction force frames 12 during the process of the steel bar stretching cylinder 13 applying tension.

[0031] A loading oil pump 15, an unloading oil valve 14, a pressure gauge 16 and a pressure sensor 17 are provided between each steel bar stretching cylinder 13 and the data acquisition system 19; the loading oil pump 15, the unloading oil valve 14, the pressure gauge 16 and the pressure sensor 17 are connected in sequence, and the pressure sensor 17 is connected to the data acquisition system 19; the steel bar stretching cylinder 13 is connected to the line between the unloading oil valve 14 and the pressure gauge 16; the steel bar stretching cylinder 13 adjusts the tension through the loading oil pump 15 and the unloading oil valve 14, the tension is displayed on the pressure gauge 16, and is transmitted to the data acquisition system 19 for recording through the pressure sensor 17.

[0032] Specifically, the normal pressurizing mechanism includes a normal reaction force frame 10, a normal loading cylinder 9, an upper loading block 7, a lower loading block 8 and a four-point compression component 6; the normal reaction force frame 10 is horizontally arranged above and below the mold respectively, and the four corners of the upper and lower normal reaction force frames 10 are fixed by pillars 25 respectively; the normal loading cylinder 9 is arranged on the upper end surface of the lower normal reaction force frame 10; the upper loading block 7 and the lower loading block 8 are respectively arranged on the upper and lower sides of the mold, and the upper loading block 7 is connected to the upper normal reaction force frame 10, and the lower loading block 8 is connected to the output end of the normal loading cylinder 9; the four-point compression component 6 is four round iron rods with the same length as the sample 5, two of which are arranged in parallel on both sides of the middle between the sample 5 and the lower loading block 8, and the other two are arranged in parallel on both sides between the sample 5 and the upper loading block 7, and the two ends of the two round iron rods on the same side are fixed by iron sheets.

[0033] The normal loading cylinder 9 is connected to the data acquisition system 19 via the normal hydraulic servo system 18. The normal hydraulic servo system is an independent system, connected to a computer via a data conductor, and controlled by computer software.

[0034] The process of testing by the present invention is as follows:

[0035] 1) Before the test, first fix and assemble the bottom plate 4, two sets of Y side plates 2, and two sets of X side plates 3;

[0036] 2) According to the designed reinforcement ratio and reinforcement position, the steel bars 1 are inserted into the steel bar holes 20 on the Y side plate 2 and the X side plate 3 to prepare the steel mesh;

[0037] 3) Use plasticine to seal the unused steel bar holes 20 to prevent leakage of the filling slurry;

[0038] 4) Put the properly proportioned filling slurry into the mold, add it to a height of 200mm and start curing;

[0039] 5) After the curing is completed, one end of the exposed part of the steel bar 1 is fixed in the clamping hole 21 on the steel bar locking fixture 11, and the other end is passed through the fixing hole on the horizontal reaction frame 12 on the opposite side, and the part leaking out after passing through the fixing hole is bent to keep it fixed;

[0040] 6) Apply prestress to the steel bar 1 in the specimen through the steel bar stretching cylinder 13 according to the design;

[0041] 7) The normal loading cylinder 9 is adjusted by the normal hydraulic servo system 18 to perform mechanical experiments on the sample. Among them, the upper loading block 7 and the lower loading block 8 are used to evenly distribute the applied pressure, the four-point compression component 6 is dedicated to the four-point compression test, the normal loading cylinder 9 is used to apply normal pressure, and the normal reaction force frame 10 is used to fix the equipment, keep it level, and maintain the overall stability of the equipment during the experiment.

[0042] 8) Collect experimental data of the experimental process through the data acquisition system 19.

[0043] The present invention applies prestress to the steel bars in the sample through the steel bar stretching cylinder 13 and the steel bar locking fixture 11. The entire device has a complete structure and can independently complete the test, overcoming the disadvantage that the traditional filling false top mold test device cannot control the prestress applied to the steel bars. The present invention is simple to operate, can adjust the prestress applied to the steel bars, and the size is closer to the actual site, which has important reference significance for actual projects.

[0044] Matters not covered in the present invention are all known technologies.

[0045] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A large-size filling false roof compression deformation failure test device under prestressed conditions, characterized by: The device comprises a bottom plate, a mold, a horizontal stretching mechanism, a normal pressurizing mechanism and a data acquisition system; the mold is a hollow rectangular parallelepiped structure, which is fixed correspondingly to the middle of the upper end surface of the bottom plate, and a number of steel bars are evenly distributed on the surrounding side walls; the horizontal stretching mechanism is provided with two groups, which are respectively distributed on the outside of the side walls of the mold, and the two groups of horizontal stretching mechanisms are perpendicular to each other, and the bottoms of the horizontal stretching mechanisms are fixedly connected to the bottom plate; the normal pressurizing mechanism is arranged between the upper and lower sides of the mold; the data acquisition system is respectively connected to the horizontal stretching mechanism and the normal pressurizing mechanism; The horizontal stretching mechanism includes two horizontal reaction force frames, a steel bar stretching cylinder, and a steel bar locking clamp; the two horizontal reaction force frames are respectively arranged on the outside of a group of opposite side walls of the mold, and the horizontal reaction force frames and their corresponding mold side walls are parallel to each other and vertically fixed to the bottom plate; the cylinder body of the steel bar stretching cylinder is vertically fixed to the middle and upper part of the horizontal reaction force frame on one side and its piston rod end corresponds to the mold side wall; the steel bar locking clamp is fixed to the piston rod end of the steel bar stretching cylinder, and a clamping hole corresponding to the steel bar hole is arranged on the end face of the steel bar locking clamp on one side corresponding to the mold side wall; the surface of the horizontal reaction force frame on the other side is provided with a fixing hole corresponding to the steel bar hole.

2. A large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 1, characterized in that: The outer ends of the horizontal reaction force frame are respectively fixedly connected to the bottom plate through triangular steel plates.

3. A large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 1, characterized in that: In each set of horizontal stretching mechanisms, two ends of two horizontal reaction force frames outside a set of side walls of the mold are fixedly connected by support rods.

4. The large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 1 is characterized by: A loading oil pump, an unloading oil valve, a pressure gauge and a pressure sensor are arranged between the steel bar stretching cylinder and the data acquisition system; the loading oil pump, unloading oil valve, pressure gauge and pressure sensor are connected in sequence and then connected to the data acquisition system via the pressure sensor; the steel bar stretching cylinder is connected to the line between the unloading oil valve and the pressure gauge.

5. The large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 1 is characterized by: The outer side of the mold is fixedly connected to the bottom plate through a fixed wall.

6. The large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 1 is characterized by: The mold side wall is a solid steel structure.

7. The large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 1 is characterized by: The normal pressurizing mechanism comprises a normal reaction force frame, a normal loading cylinder, a loading block and a four-point compression component; the normal reaction force frame is horizontally arranged on the upper and lower sides of the mold, and the four corners of the normal reaction force frames on the upper and lower sides of the mold are fixedly connected by pillars; the normal loading cylinder is arranged above the lower normal reaction force frame; the loading blocks are correspondingly arranged on the upper and lower sides of the mold, and the upper loading block is connected to the upper normal reaction force frame, and the lower loading block is connected to the output end of the normal loading cylinder; the four-point compression component is four round iron rods with the same length as the sample, two of which are arranged in parallel between the mold and the lower loading block, and the other two are arranged in parallel between the mold and the upper loading block, and the two ends of the two round iron rods on the same side are fixed by iron sheets.

8. A large-size filling false roof compression deformation failure test device under prestressed conditions according to claim 7, characterized in that: The normal loading oil cylinder is connected to the data acquisition system through a normal hydraulic servo system.

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