Physical test device for simulating residual deformation similarity of caving zone and fissure zone of goaf

Abstract

The utility model discloses a physical test device for simulating residual deformation similarity of a caving zone and a fissure zone in a goaf, which comprises a steel frame, side plates are fixedly arranged on the left side and the right side of the steel frame, and a lower transparent protective plate and an upper transparent protective plate are sequentially arranged on the front side and the back side of the steel frame; a caving zone, a fissure zone and a bending zone are sequentially laid in the model laying space from bottom to top, and the caving zone and a part of the fissure zone jointly form a grouting treatment area; an induced deformation large pipe is embedded in a non-grouting treatment area of the caving zone in advance, and the induced deformation large pipe penetrates out of a large hole in the lower transparent protective plate located on the rear portion; induced deformation small pipes are embedded in a non-grouting control area of the fissure zone in advance, and the induced deformation small pipes penetrate out of small holes in the lower transparent protection plate located on the rear portion. The testing device is reliable in performance, the applied testing method can efficiently, conveniently and visually research the residual deformation rule of the old goaf, and guidance can be provided for production and work such as goaf treatment.

Description

Technical Field

[0001] The utility model belongs to the technical field of similarity physical experiments, and relates to a residual deformation analysis model for goaf areas. Specifically, it is a similarity physical experiment device for simulating residual deformation of caving zones and fracture zones in goaf areas, and is used for analyzing and simulating residual deformation of goaf areas, and in particular, deformation release laws of caving zones and fracture zones. Background Art

[0002] The deformation of the goaf will destroy the mechanical properties of the building foundation, causing uneven settlement and deformation of the foundation. This will cause structural damage such as cracks, tilts, and fractures in the building, affecting the safety of the building. The deformation stage of the goaf is generally divided into four stages: initial stage, development stage, full stage, and residual stage. Generally speaking, the initial stage is when the goaf is just formed, generally a few days to a few months; the goaf gradually expands during the development stage, and the time of this stage is generally a few months to a few years; the stability of the goaf tends to be stable during the full stage, and the time of this stage is generally a few years; in the residual stage, the deformation of the goaf is mainly caused by the gradual closure of pores in the caving zone and the fracture zone, and the time of this stage is generally a few years to decades. After the mining is completed, the development and utilization of the area above the mining area has become a research hotspot in recent years. For the goaf where the deformation of the overburden tends to be stable, although there is no large-scale collapse or caving, it still needs to be monitored and prevented. At this stage, the main problem is the reuse of the goaf land and the governance of the goaf. At this stage, the goaf is relatively stable and there is a certain period of mining. When constructing structures above the goaf, for safety reasons, it is necessary to control and study their deformation and failure laws.

[0003] Similarity physical test is a scientific research method. It is an experimental method to study the mechanical movement of goaf by making a model similar to the prototype. Through similarity test, the deformation law of goaf can be better studied, and monitoring and prevention plans can be designed. Similarity physical test is one of the important means to analyze the deformation of goaf. For a long time, the deformation of goaf has mainly studied the surface movement deformation caused by mining. Through similarity physical test, the roof collapse or caving caused by mining is simulated, and the irregular depression on the surface is analyzed. However, when a building is built in the goaf, the goaf is often in the full stage or residual stage. In these stages, the deformation of the goaf is released in the entire area of ​​the caving zone and the fracture zone. In addition, the rock structure in the fracture zone and the caving zone is relatively broken, and the deformation law is quite different from that of traditional similar materials (such as sand, gypsum, etc.).

[0004] Although the use of similarity physical experiments to study the deformation laws of goaf areas has a long history, the research has focused on analyzing the deformation characteristics caused by goaf mining, while there is little research on the overall deformation of caving zones and fracture zones. Utility Model Content

[0005] Similarity physical test is a reliable method to study the deformation of goaf. Traditional similarity physical test mainly studies the deformation and damage caused by mining.

[0006] The utility model aims to provide a similarity physical test device for simulating the residual deformation of the caving zone and the fracture zone in the goaf, and on this basis simulate the influence of grouting reinforcement on the deformation of the goaf, so as to provide a basis for the goaf management and deformation.

[0007] The utility model is realized by adopting the following technical solutions:

[0008] A physical test device for simulating the similarity of residual deformation of caving zones and fracture zones in goaf areas comprises a steel frame, side panels are fixedly provided on the left and right sides of the steel frame, a lower transparent protective plate and an upper transparent protective plate are respectively provided in sequence in the front and rear of the steel frame, and the side panels located on the left and right sides and the lower transparent protective plate and the upper transparent protective plate located on the front and rear sides together constitute a model laying space; caving zones, fracture zones and bending zones are laid in sequence from bottom to top in the model laying space, and a part of the caving zones and the fracture zones together form a grouting control area; a large deformation-inducing tube is pre-buried in the non-grouting control area of ​​the caving zone, and the large deformation-inducing tube passes through a large hole on the lower transparent protective plate at the rear; a small deformation-inducing tube is pre-buried in the non-grouting control area of ​​the fracture zone, and the small deformation-inducing tube passes through a small hole on the lower transparent protective plate at the rear.

[0009] In order to further obtain better test results, a counterweight block is arranged above the bending belt to increase gravity, so that the test can reach the required formation pressure and better simulate the situation of deep goaf.

[0010] Further preferably, the total height of the falling belt and the crack belt is the same as the height of the lower transparent guard plate. The height of the bending belt is the same as the height of the upper transparent guard plate. Bolt connection holes are provided on the front and rear sides of the steel frame, and the lower transparent guard plate and the upper transparent guard plate are respectively connected to the front and rear sides of the steel frame by bolts. Support feet are fixed at the bottom of the side plate to make the device more stable and convenient for practical application.

[0011] Further preferably, when the utility model device is applied, black and white crushed stones of different particle sizes can be used to simulate the caving zone and the fracture zone, so as to better simulate the influence of residual deformation on the surface. The loose body (referring to the caving zone and the fracture zone) is paved with black and white crushed stones. The caving zone is paved with black and white crushed stones with a diameter of 10 to 16 mm and a height of 12 cm; the fracture zone is paved with black and white crushed stones with a diameter of 3 to 5 mm and a height of 24 cm; in this way, the stress diffusion of the caving zone is greater than that of the fracture zone, which is more in line with the actual situation. The grouting treatment area is paved with a slurry composed of crushed stone, cement, fly ash and water, and the length of the grouting treatment area accounts for 1 / 3 of the length of the caving zone and the fracture zone; grouting can be selected according to the needs of the experimental objectives. Setting up the grouting treatment area can study the influence of grouting treatment on deformation. Of course, the deformation characteristics of residual deformation can also be studied without setting up the grouting treatment area. The bending zone is paved with conventional similarity materials. The diameter of the large deformation-inducing tube is 4 cm, and the number is 5; the diameter of the small deformation-inducing tube is 2 cm, and the number is 18.

[0012] Compared with the prior art, the technical solution provided by the utility model has the following advantages:

[0013] First, using gravel to simulate the residual deformation of the goaf can be closer to the actual situation than traditional similarity physical experiments and can help study the goaf management issues.

[0014] Second, it can fully simulate the deformation, closure and stress conduction process of loose bodies in the caving zone and fracture zone of the goaf.

[0015] Third, deformation analysis of loose body areas can be realized by using black and white gravel for deformation simulation.

[0016] Fourth, not only can the deformation process of the goaf in the residual deformation stage be studied, but also the effect of grouting on deformation can be studied.

[0017] The utility model has reasonable design and reliable performance of the test device (model). The applied test method can efficiently, conveniently and intuitively study the residual deformation law of old goaf areas, can provide guidance for production and work such as goaf area management, and has good practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present utility model, and together with the description, are used to explain the principles of the present utility model.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 The utility model device schematic diagram is shown.

[0021] Figure 2 Schematic diagram of the lower transparent guard plate.

[0022] Figure 3 Schematic diagram of the upper transparent guard plate.

[0023] Figure 4 The front side (front side) of the utility model is shown as a whole.

[0024] Figure 5 The back side (rear side) of the utility model is shown as a whole.

[0025] Figure 6 Schematic diagram showing the structure of the similarity test model.

[0026] Figure 7 A schematic diagram showing the flow of the method for conducting a similarity experiment.

[0027] In the figure: 1-steel frame, 2-side panel, 3-lower transparent guard plate, 4-upper transparent guard plate, 5-counterweight, 6-support foot, 7-bolt connection hole, 8-large hole, 9-small hole, 10-large tube for inducing deformation, 11-small tube for inducing deformation, 12-scaling zone, 13-crack zone, 14-bending zone, 15-grouting treatment area, 16-hole for inducing deformation in the scalping zone, 17-hole for inducing deformation in the crack zone. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the scheme of the utility model will be further described below. It should be noted that the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

[0029] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0031] The specific embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0032] The caving zone refers to the part of the rock layer where the overlying rock mass of the coal seam completely collapses after the working face is mined. The fracture zone refers to the part of the rock layer above the caving zone where the fracture concentration of each rock layer has expanded to (or close to) the entire thickness. The rocks in the caving zone and the fracture zone are characterized by irregularity, fragmentation and poor density. There are many gaps between the rock blocks, strong connectivity, and they are very loose. The residual deformation of the goaf refers to the phenomenon that the surface of the goaf of a coal mine continues to sink slowly after experiencing the main deformation stage. The main reason is the closure of the loose rocks in the caving zone and the fracture zone. This process is often encountered in the reuse and management of the goaf. At this time, the goaf is relatively stable and has been mined for a certain period of time. For safety reasons, when constructing structures above the goaf, it is necessary to study its deformation and failure laws. Traditional similarity physical experiments mainly study the deformation and failure characteristics of the overburden caused by mining, and there are few studies on the residual deformation of the goaf. The utility model combines the characteristics of the caving zone and the fracture zone and proposes a similarity physical test device for simulating the deformation release of the caving zone and the fracture zone of the goaf.

[0033] A physical test device for simulating the residual deformation similarity of the caving zone and the fracture zone in the goaf, such as Figure 1 , 4 As shown in FIG. 5 , the steel frame 1 includes a side plate 2 fixedly disposed on the left and right sides of the steel frame 1, and a support foot 6 fixedly disposed on the bottom of the side plate 2. Bolt connection holes 7 are disposed on the front and rear sides of the steel frame 1. The lower transparent guard plate is as shown in FIG. Figure 2 As shown, bolt connection holes are provided on both sides thereof, and large holes 8 and small holes 9 are provided at corresponding positions. Figure 3As shown, bolt connection holes are provided on both sides thereof. The lower transparent guard plate 3 and the upper transparent guard plate 4 are respectively connected to the front and rear sides of the steel frame 1 by bolts. Then the side panels 2 located on the left and right sides and the lower transparent guard plate 3 and the upper transparent guard plate 4 located on the front and rear sides together constitute the model laying space. In the model laying space, the caving belt 12, the crack belt 13 and the bending belt 14 are laid in sequence from bottom to top, and the caving belt 12 and a part of the crack belt 13 together form the grouting treatment area 15; the non-grouting treatment area of ​​the caving belt 12 is pre-buried with an induced deformation large pipe 10, and the induced deformation large pipe 10 passes through the large hole 8 on the lower transparent guard plate 3 at the back; the non-grouting treatment area of ​​the crack belt 13 is pre-buried with an induced deformation small pipe 11, and the induced deformation small pipe 11 passes through the small hole 9 on the lower transparent guard plate 3 at the back. A counterweight 5 is arranged above the bending belt 14.

[0034] The total height of the falling zone 12 and the crack zone 13 is the same as the height of the lower transparent guard plate 3. The height of the bending zone 14 is the same as the height of the upper transparent guard plate 4.

[0035] This embodiment takes the K9+320-K11+360 section of the Fenyang to Shilou Expressway as the object, which is located above the goaf of the No. 2 coal seam in Gaoyang Coal Mine, and makes a corresponding physical test device simulating the residual deformation similarity of the caving zone and the fracture zone of the goaf.

[0036] The coal seam adopts longwall fully mechanized mining method, with a mining thickness of 2 to 4 meters, a recovery rate of 85%, and a mining depth of 120 to 180 meters. There is residual deformation on the surface. In order to better simulate the residual deformation process of the old goaf, black and white crushed stones are used to simulate the caving zone and fracture zone of the goaf.

[0037] The gravels in the caving zone and the fracture zone are composed of black and white gravels. The gravels mainly move in two-dimensional planes in the experiment, which is convenient for analyzing and capturing the displacement characteristics of loose bodies. The caving zone is paved with black and white gravels with a diameter of 10-16 mm and a height of 12 cm. The fracture zone is paved with black and white gravels with a diameter of 3-5 mm and a height of 24 cm. In the model, pipes of different thicknesses are buried in the caving zone and the fracture zone to simulate the process of crack closure in the goaf. Among them, the pore density ratio of the caving zone and the fracture zone is 4:1. The diameter of the large deformation-inducing pipe buried in the caving zone is 4 cm, with a total of 5 pipes, which are reasonably distributed in the non-grouting treatment area of ​​the caving zone. The diameter of the small deformation-inducing pipe buried in the fracture zone is 2 cm, with a total of 18 pipes, which are reasonably distributed in the non-grouting treatment area of ​​the fracture zone. The equivalent amount of simulated residual deformation is 1.5 cm. The strata in the bending zone are paved with conventional similar materials, with sand as aggregate, gypsum as bonding material, and calcium carbonate as auxiliary cementing material. The height of the bending zone is 44 cm, and the similarity ratio is 1: 200. As shown in Table 1, from bottom to top in the bending zone are P1s sandstone (height 4.4 cm), P1x mudstone (height 20.4 cm), and N2di+pi conglomerate (height 19.2 cm).

[0038] The grouting treatment area 15 is paved with a thick slurry (not very fluid) composed of crushed stone, cement, fly ash and water; for example, the grouting treatment area located in the caving zone is paved with black and white crushed stone with a diameter of 10 to 16 mm and a thick slurry composed of cement, fly ash and water; the grouting treatment area located in the fissure zone is paved with black and white crushed stone with a diameter of 3 to 5 mm and a thick slurry composed of cement, fly ash and water; the mass ratio of cement to fly ash is about 15:85. In this embodiment, the length of the grouting treatment area 15 accounts for about 1 / 3 of the length of the caving zone 12 / fissure zone 13 (about 40 cm). Figure 6 The width (thickness) of the entire test model is 40 cm, the height is 80 cm, and the length is 120 cm.

[0039] Table 1 Similarity physical test parameters

[0040]

[0041] Note: The first digit of the mix number is the mass ratio of sand to binder, and the last two digits are the mass ratio of gypsum to calcium carbonate. For example, 955 means that the mass of sand is 9 times that of binder, and the binder is a mixture of gypsum and calcium carbonate in a ratio of 5:5.

[0042] The following is the process of making a similarity physical test device to simulate the deformation release of the caving zone and the fracture zone of the goaf area and the method of conducting similarity physical test. Figure 7 shown.

[0043] (1) Material preparation: model steel frame, transparent protective plates on the front and rear sides, compaction steel plates, leveling rollers, mixers, electronic scales, black and white gravel, and other materials.

[0044] Design the height and residual deformation volume of the caving zone and the crack zone, install the guard plate according to the designed height and make holes at the guard plate position. Design the appropriate mix ratio for the bending zone height position according to the conventional method of similarity physical test.

[0045] (2) Install the guard plate: Install a 36 cm high acrylic plate (as the lower transparent guard plate) at the bottom of the front and rear sides of the steel frame. On the lower transparent guard plate at the rear side, open 5 large holes at the corresponding falling zone positions and 18 small holes at the corresponding crack zone positions. Install a 44 cm high acrylic plate (as the upper transparent guard plate) at the upper part of the front and rear sides of the steel frame.

[0046] (3) Laying loose material

[0047] Laying of the caving zone: First, insert a large deformation-inducing pipe into the large hole to occupy the space; then, in the non-grouting treatment area of ​​the caving zone (about 80 cm in length), directly use black and white crushed stones with a diameter of 10 to 16 mm to lay them layer by layer; for the grouting treatment area of ​​the caving zone (about 40 cm in length), use black and white crushed stones with a diameter of 10 to 16 mm and a thick slurry composed of cement, fly ash and water to lay them layer by layer in the non-grouting treatment area until the height of the caving zone is 12 cm.

[0048] Laying of the fracture zone: First, insert a small deformation-inducing tube into the small hole to occupy the space; then, in the non-grouting treatment area of ​​the fracture zone (about 80 cm in length), directly use black and white crushed stones with a diameter of 3 to 5 mm to lay them layer by layer; for the grouting treatment area of ​​the fracture zone (about 40 cm in length), use a thick slurry composed of black and white crushed stones with a diameter of 3 to 5 mm and cement, fly ash and water to lay them layer by layer in the non-grouting treatment area until the height of the fracture zone is 24 cm.

[0049] (4) Manufacturing curved belts: According to the ratio in Table 1, weigh the sand, gypsum, and calcium carbonate required for each layer, add an appropriate amount of water, mix the materials and water, and stir evenly, and use mica powder to simulate the layer; from bottom to top, make P1s sandstone, P1x mudstone, and N2di+pi conglomerate in sequence. Pour the mixed materials into the simulation space and flatten them, scrape them flat with a compacting steel plate, and compact them with a leveling roller. Sprinkle a layer of mica powder to simulate the layer every 2 cm of material.

[0050] (5) Curing: After laying the groundwork, cure for 8 days to allow the model to dry and solidify.

[0051] (6) Painting the model and making monitoring points and speckles: After the model is dried, brush a layer of white light calcium carbonate on the surface of the model's bending belt to form a white background; wait for 3 days for the white calcium carbonate to solidify, draw the monitoring line, install the reflective sheet, and draw the speckle; the monitoring line is drawn with an ink fountain, and the reflective sheet is made of cotton thread to make a guide grid, which is then inserted into the model with a thumbtack. When drawing the speckle, first use a hole puncher to randomly punch holes in the plastic cardboard, and then use spray paint to spray it.

[0052] (7) Induced deformation release: Pull out the large and small deformation-inducing tubes to make the loose body gravel start to move and deform. Five caving zone induced deformation holes with a diameter of about 4 cm are formed in the caving zone, and 18 fracture zone induced deformation holes with a diameter of about 2 cm are formed in the fracture zone. The equivalent amount of simulated residual deformation is 1.5 cm, and the deformation law between the loose body and the bending zone strata is observed.

[0053] The test results show that after the pipe is pulled out, the deformation gradually transmits upward, but due to the existence of the grouting treatment area, the deformation law has changed. The deformation diffusion curve near the treatment area is steeper, and the deformation on one side of the treatment area is prominent. It is difficult for the deformation to spread to the inside of the treatment area. Through the experiment, it can be found that a large number of cracks are developed on one side of the treatment area, forming a large-scale crack concentration area. There are almost no cracks above the treatment area. The existence of the treatment area has led to a change in the law of overburden failure. More deformation is concentrated on one side of the grouting treatment area. And the deformation differences and deformation characteristics of the caving zone, fracture zone, and bending zone can be clearly compared.

[0054] The model prepared by the utility model can use black and white crushed stones to simulate the residual deformation of the goaf. Compared with the traditional similarity physical experiment, it can fully simulate the deformation, closure and stress conduction process of the loose body in the caving zone and the fracture zone of the goaf. The simulation result is more in line with the actual situation. It can not only study the deformation characteristics of the residual deformation stage of the goaf, but also study the control effect of grouting on deformation.

[0055] The above is only a specific implementation of the utility model, which enables those skilled in the art to understand or implement the utility model. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A physical test device for simulating the similarity of residual deformation of caving zone and fracture zone in goaf area, characterized by: The invention comprises a steel frame (1), wherein side panels (2) are fixedly provided on the left and right sides of the steel frame (1), and a lower transparent protective panel (3) and an upper transparent protective panel (4) are provided in sequence at the front and rear of the steel frame (1), respectively. The side panels (2) located on the left and right sides and the lower transparent protective panel (3) and the upper transparent protective panel (4) located on the front and rear sides together constitute a model laying space; a fall zone (12), a crack zone (13) and a bending zone (14) are laid in sequence from bottom to top in the model laying space, and the fall zone (1 2) and a part of the fracture zone (13) together form a grouting treatment area (15); a large deformation inducing tube (10) is pre-buried in the non-grouting treatment area of ​​the caving zone (12), and the large deformation inducing tube (10) passes through a large hole (8) on the lower transparent protective plate (3) at the rear; a small deformation inducing tube (11) is pre-buried in the non-grouting treatment area of ​​the fracture zone (13), and the small deformation inducing tube (11) passes through a small hole (9) on the lower transparent protective plate (3) at the rear.

2. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 1, characterized in that: A counterweight block (5) is arranged above the bending belt (14).

3. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 1 or 2, characterized in that: The total height of the falling zone (12) and the crack zone (13) is the same as the height of the lower transparent protective plate (3).

4. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 3, characterized in that: The height of the curved strip (14) is the same as the height of the upper transparent protective plate (4).

5. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 4, characterized in that: Bolt connection holes (7) are provided on the front and rear sides of the steel frame (1), and the lower transparent guard plate (3) and the upper transparent guard plate (4) are respectively connected to the front and rear sides of the steel frame (1) by bolts.

6. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 5, characterized in that: Support feet (6) are fixedly provided at the bottom of the side plate (2).

7. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 6, characterized in that: The caving zone (12) is paved with crushed stones with a diameter of 10 to 16 mm; the fissure zone (13) is paved with crushed stones with a diameter of 3 to 5 mm; the grouting treatment area (15) is paved with a slurry consisting of crushed stones, cement, fly ash and water; and the bending zone (14) is paved with sand as aggregate, gypsum as bonding material and calcium carbonate as auxiliary bonding material.

8. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 6, characterized in that: The large deformation-inducing tube (10) has a diameter of 4 cm and is 5 in number; the small deformation-inducing tube (11) has a diameter of 2 cm and is 18 in number.

9. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 8, characterized in that: The length of the grouting treatment area (15) accounts for 1 / 3 of the length of the caving zone (12) and the fissure zone (13).

10. A physical test device for simulating residual deformation similarity of caving zone and fracture zone in goaf according to claim 9, characterized in that: The height of the caving zone (12) is 12 cm, and the height of the fissure zone (13) is 24 cm.

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