Water bleeding filling retaining wall structure and phosphogypsum backfilling method using same

Abstract

The invention relates to the technical field of mine filling, and particularly discloses a bleeding filling retaining wall structure and an ardealite backfilling method using the same, the bleeding filling retaining wall structure comprises a wall body arranged in a mining roadway of a filling mining method, the wall body is of an arch structure built by special-shaped bricks, and the special-shaped bricks are of an arch structure with one end large in size and the other end small in size. A plurality of pressure-bearing edges are constructed on the surface of the special-shaped brick, and a plurality of hollow structures are defined by the pressure-bearing edges. The arch protruding side of the wall arch structure faces the side of a goaf, arch feet of the wall arch structure are directly connected with rock masses on the two sides in a masonry mode, and the special-shaped bricks are formed by 3-8 mm melon pebbles and binding materials in an extrusion mode. The technical problems that in the prior art, a filling retaining wall is provided with a drainage structure in order to improve the drainage capacity, so that the whole structure of the retaining wall is damaged, structural weak points exist, and collapse is likely to happen at the drainage structure are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of mine filling, in particular to a water seepage filling retaining wall structure and a phosphogypsum backfilling method using the structure. Background Art

[0002] With the continued advancement of green mining, in-fill mining has become one of the most commonly used methods in metal mining and phosphate chemical mining. In-fill mining refers to a mining method that uses filler to backfill the goaf during the mining process to control ground pressure, support the surrounding rock, and reduce or delay the damage and movement of the surrounding rock in the goaf after mining. Mining operations are then carried out on or under the protection of the resulting filler.

[0003] After backfilling, the slurry needs to be fixed in the mine goaf and prevent it from moving, so that it can support the surrounding rock, thereby controlling the ground pressure of the mining area and reducing or delaying the damage and movement of the surrounding rock in the post-mining goaf. Therefore, technicians will set up a backfill retaining wall in the mining tunnel after backfilling, and use the backfill retaining wall to seal the backfilling area to prevent the slurry from leaking out and ensure that the slurry does not move. At present, the construction of backfill retaining walls at home and abroad mainly includes masonry retaining wall method and shotcrete wall method. The masonry retaining wall method uses hollow bricks and other materials to build the backfill retaining wall, and then sprays the outer surface of the retaining wall for reinforcement. This method has the advantages of low cost and simple construction process. The shotcrete wall method is to first use steel mesh, sack cloth and steel bars to tie a backfill retaining wall curtain at the designed position of the retaining wall, fix it to the anchor rods reserved on the top of the tunnel, and then use a wet spraying trolley to spray wet concrete on the curtain. This method has the advantages of fast construction speed and strong retaining wall.

[0004] Although the backfill retaining wall in the above-mentioned prior art can achieve the effect of sealing the backfill slurry to a certain extent, these two methods do not take into account that the backfill slurry contains a large amount of water. If the backfill material contains a large amount of water and the water cannot be discharged, the lateral pressure generated is large, and the premise collapse or collapse may occur. In addition, the drainage is poor, the water cannot be discharged in time, and it will take longer for the backfill to reach the expected strength, and the final strength will be lower, which greatly reduces the filling efficiency and filling quality of the mine. In order to solve this problem, the prior art usually provides water diversion and drainage structures on the backfill retaining wall. For example, the patent document with application number 202111035423.3 discloses a masonry-type water-filtration backfill retaining wall block structure and assembly method. This technology provides a semi-cylindrical diversion trough on the block for drainage. For example, the patent document with application number CN201810667193.4 discloses an in-situ treatment method for tailings water in a mine and a permeable reactive filling retaining wall. A water diversion trough is opened at the bottom of the retaining wall facing the goaf, and a plurality of pipes arranged in a vertical direction are fixed on the skeleton on one side of the goaf. The pipes are connected to the water diversion trough, and filter media are filled in the pipes. A water inlet is set on the side of the pipe facing the goaf, and drainage is carried out by combining the pipes and the water diversion trough.

[0005] Although the filling retaining wall disclosed in the above-mentioned prior art ensures the dewatering ability of the retaining wall, this technical solution has the disadvantages of complex retaining wall structure, long construction period, poor drainage performance after the drainage structure is blocked, etc. In addition, the drainage structure set up in this retaining wall destroys the integrity of the retaining wall and becomes a weak point of the overall structure, and it is easy to collapse from the drainage structure. Summary of the Invention

[0006] The purpose of the present invention is to provide a water seepage filling retaining wall structure and a phosphogypsum backfilling method using the structure, so as to solve the technical problem mentioned above that the filling retaining wall of the prior art is provided with a drainage structure in order to improve the drainage capacity, resulting in the destruction of the overall structure of the retaining wall, the existence of structural weak points, and easy collapse from the drainage structure.

[0007] In order to solve the above problems, the technical solution adopted by the present invention is as follows: a seepage filling retaining wall structure and a phosphogypsum backfilling method using the structure, including a wall set in a mining tunnel of the filling mining method, wherein the wall is an arch structure built of special-shaped bricks, the special-shaped bricks are wedge-shaped structures with a large size at one end and a small size at the other end, and a plurality of pressure-bearing edges are constructed on the surface of the special-shaped bricks, which form a plurality of hollow structures together. The convex side of the wall arch structure faces the side of the goaf, and the arch foot of the wall arch structure is directly connected to the rock mass on both sides. The special-shaped bricks are extruded and formed by 3~8mm melon grains and cementitious materials.

[0008] The beneficial effects of this embodiment are: 1. In order to improve drainage capacity, the prior art installs a drainage structure within the retaining wall. This structure destroys the integrity of the retaining wall, resulting in weak points in the overall structure. When the lateral pressure on the weak points formed by the drainage structure is too great, the drainage structure is easily damaged, which in turn causes the collapse of the entire retaining wall. The water-seeping filling retaining wall structure of the present application utilizes the characteristics of special-shaped bricks that are extruded from melon grains and cementitious materials and the hollow structure on the surface, which reduces the weight of the bricks, increases water permeability, saves materials, and has good water filtration function. Therefore, the present application does not require the installation of a drainage structure at any position on the wall surface, and has good overall consistency, uniform force, and strong bearing capacity. The arched structure facing the side of the goaf allows it to effectively transform lateral loads, extend along the wall, and transmit thrust to the rock masses on both sides. It also increases the contact area between the filling slurry and the retaining wall, providing a larger drainage area and quickly draining excess water from the filling body. Compared with the prior art, the present application has good water filtration performance, a simple structure, and its structure is more reliable and stable than the prior art.

[0009] 2. When backfilling phosphate mines and coal mine goafs, phosphogypsum solid waste and coal gangue solid waste are mostly backfilled. Solid wastes such as phosphogypsum have very strong water absorption capacity. When it is prepared into a backfill slurry, it requires much more water than ordinary mortar, so it contains a lot of water. According to Pascal's law, we know that the pressure of water on an object is equal in all directions. Under the same conditions, the lateral pressure of water is greater than the lateral pressure of sand. Therefore, after the phosphogypsum containing a large amount of water is filled into the goaf, the lateral pressure it generates is very large. The retaining wall in the prior art is a vertical structure. The vertical retaining wall relies on the bonding force between the bricks to bear the pressure. This makes the wall of the vertical filling retaining wall unable to provide sufficient strength to resist the lateral pressure of the backfilled phosphogypsum slurry. A large amount of concrete needs to be sprayed on the wall surface to enhance its bonding force. The retaining wall of the present application is designed as an arch structure. The arch retaining wall bears pressure by the extrusion force between the bricks. After the lateral filling slurry pressure of the arch structure acts on the arch, it can transfer the force to the supports around it, and convert the huge lateral load into horizontal thrust to the rock masses on both sides. Therefore, compared with the vertical filling retaining wall in the existing technology, it has a stronger load-bearing capacity when dealing with highly water-absorbent backfill slurries such as phosphogypsum.

[0010] 4. Since arched retaining walls primarily bear pressure through the squeezing force between bricks, the primary indicator of their pressure-bearing capacity is the pressure the bricks can withstand. The special-shaped bricks of this application are placed on the wall with their length along the thickness of the wall, and multiple pressure-bearing ridges are provided along the length of the bricks to enhance their pressure-bearing capacity. The hollow structure formed by the pressure-bearing ridges further enhances the water filtration performance of this application. Therefore, compared with the existing technology, this application has greater strength and better water filtration performance.

[0011] 5. The special-shaped bricks of this application can be quickly positioned. Therefore, during construction, they can be quickly transported to the tunnel and the wall completed quickly using masonry mortar. This shortens construction time compared to prior art retaining walls that incorporate drainage structures and fill with water. Furthermore, the wedge-shaped special-shaped bricks offer superior compressive strength, and the arched design perfectly leverages the high compressive strength of the special-shaped bricks. Arched retaining walls constructed with these special-shaped bricks exhibit significantly lower bending moments and shear forces within the arch. Under the same conditions, this improves rigidity and increases span. This structure is particularly advantageous for larger spans. Therefore, the curvature of the arch can be easily adjusted by adjusting the width of the special-shaped bricks according to the width of the mine tunnel.

[0012] 6. The arch retaining wall built with special-shaped bricks is completely consistent with the uneven roadway contour. Special-shaped brick masonry has the adaptability to different roadway contours, so this application can be widely used in various mining sites.

[0013] 7. Traditional masonry retaining walls cost approximately 5,000 to 10,000 yuan per square meter, shotcrete retaining walls cost approximately 20,000 yuan per square meter, and grouting-type backfill retaining walls cost approximately 3,000 yuan per square meter. The special-shaped bricks used in this invention can be extruded from construction waste sand and gravel and a gelling agent, costing approximately 0.1 yuan per square meter. Therefore, their cost is much lower.

[0014] Furthermore, the strength of the special-shaped bricks in the middle of the wall in the height direction is higher than that of the special-shaped bricks at the bottom. The arched wall should bear the greatest pressure in the middle, and the pressure at the bottom will be reduced to a certain extent (gypsum has a certain viscosity, the bottom bears a large gravity, and the fluidity is weakened). However, the bottom has a large amount of water seepage, so the strength of the bottom bricks (pressure bearing capacity) can be sacrificed to enhance its permeability.

[0015] Furthermore, the hollow structure on the special-shaped brick is also a wedge-shaped structure with a larger size at one end and a smaller size at the other end, and the wedge direction is consistent with that of the special-shaped brick.

[0016] Furthermore, the gelling material is a hydraulic gelling material. Since water needs to be filtered, a hydraulic gelling material needs to be selected to ensure strength.

[0017] Furthermore, the hydraulic cementitious material is a mixed cementitious material of high-temperature calcined phosphogypsum, glass fiber, mineral powder, and cement. When phosphogypsum is used as a slurry for backfilling, it contains a large amount of water, which results in a large amount of excess water in the filling body that needs to be discharged during the cementing process or after the cementing is completed. In order to ensure that the strength development of the filling body can meet the mining needs of the surrounding area as soon as possible, how to safely and quickly discharge excess water is a key issue in filling mining. The present application adds glass fiber to the cementitious material, and while using glass fiber as the rigid skeleton of the special-shaped bricks to enhance the strength and toughness of the special-shaped bricks, the glass fiber is used to enhance the water filtration performance of the special-shaped bricks. Therefore, compared with other retaining wall blocks in the prior art, the hollow structure of the special-shaped bricks of the present application, combined with the characteristics of containing glass fiber, has better water filtration performance.

[0018] Furthermore, the hollow structure on the special-shaped brick is an elliptical groove, and the size of the hollow structure decreases along the wedge shape of the special-shaped brick from large to small. The hollow structure of the elliptical groove makes the pressure-bearing edge also have an arched structure, which can transfer pressure to both ends and further enhance the strength of the special-shaped brick. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the water seepage filling retaining wall structure after masonry of the present invention. Figure 2 for Figure 1 Top view of the water-fill retaining wall structure. Figure 3 This is a schematic diagram of the structure of the special-shaped brick of the present invention. Figure 4 It is a top view of the special-shaped brick of the present invention. DETAILED DESCRIPTION

[0020] The following is further described in detail through specific implementation methods: The reference numerals in the drawings of the specification include: contact end 1, retracted end 2.

[0021] As attached Figure 1-4 As shown: Example 1 A water seepage filling retaining wall structure includes a wall body. Before building the wall body, it is necessary to analyze the goaf and the tunnel where the retaining wall needs to be constructed in the mining tunnel, and select a tunnel location with stable rock masses on both sides and a smaller tunnel cross-section for construction. It is best to select an inner wedge-shaped location for construction. In this way, the arched retaining wall after construction can better transform the lateral load, extend along the wall body, and transfer the thrust to the rock masses on both sides.

[0022] The wall blocks are made of special-shaped bricks, such as Figure 3 、 Figure 4As shown, its main body is a wedge-shaped building block with a large size at one end and a small size at the other end in the length direction. The large end is the contact end 1 facing the goaf, and the small end is the retracted end 2. The surface of the special-shaped brick is constructed with several pressure-bearing ridges, and the pressure-bearing ridges enclose several hollow structures. The hollow structure is consistent with the special-shaped brick and is also a wedge-shaped structure with a large size at one end and a small size at the other end. The wedge-shaped direction of the hollow structure is consistent with the special-shaped brick. Its size can be adjusted according to actual conditions. In order to better describe its wedge-shaped structure, in this embodiment, the height of the special-shaped brick is 115mm, the contact end 1 of the brick is 250mm, and the retracted end 2 is 240mm. The hollow structure is as shown in FIG. Figure 4 As shown, three groups of special-shaped bricks are arranged along the length of the bricks. The hollow structure gradually decreases in size from the contact end 1 to the inward end 2. In this embodiment, the widths are 90-88, 88-85, and 83-80, respectively. The special-shaped bricks are extruded from 3-8mm guami stones and a cementitious material. The cementitious material used in this invention is a composite material of raw phosphogypsum calcined at high temperature (800°C), glass fiber, mineral powder, and cement.

[0023] During the laying process, the special-shaped bricks are laid flat in the tunnel. When laying flat, it is necessary to ensure that the length direction of the special-shaped bricks is placed along the thickness direction of the wall, so that the pressure bearing direction of the special-shaped bricks is the length direction. The contact end 1 is connected to the contact end 1, and the inner end 2 is connected to the inner end 2. Since the size of the contact end 1 is large and the size of the inner end 2 is small, the special-shaped bricks of this application will naturally form the following after the laying process is completed. Figure 2 The arch structure shown. It is necessary to ensure that the contact end 1 is facing the goaf during masonry, that is, to ensure that the convex side of the arch structure is facing the goaf after the masonry is completed. When masonry is carried out, a layered masonry method is adopted. After the first layer of special-shaped bricks is laid flat, a layer of cement mortar is applied on it, and then the second layer of special-shaped bricks is laid flat. The work is repeated alternately until the retaining wall is completed. After completion, the retaining wall structure is filled with water. Figure 1 As shown in the figure, it is worth noting that the strength of the arched wall in this application is inconsistent along its height. The strength of the special-shaped bricks in the middle of the wall is higher than that of the special-shaped bricks at the bottom. This is because, during the sealing filling, the pressure in the middle is the greatest, while the pressure at the bottom is somewhat reduced (the gypsum has a certain viscosity, and the bottom is subjected to a large gravity, which reduces its fluidity). However, the bottom seeps a lot, so the bottom brick strength (pressure bearing capacity) is sacrificed to enhance its permeability.

[0024] Because the arch is naturally formed by special-shaped bricks, the width of the contact end 1 and the inner end 2 of the special-shaped bricks need to be designed and adjusted according to the width of the mine before laying. By changing the curvature of the arch and utilizing the curvature, the lateral load can be better transferred to both ends.

[0025] A method for backfilling phosphogypsum by using seepage water to fill a retaining wall structure comprises the following steps: Step 1: Hoist brick materials, select an inner wedge-shaped roadway with a small roadway section and stable surrounding rock as the retaining wall construction location, and hoist the special-shaped bricks of this application to the retaining wall construction location for preparation; Step 2: Lay the special-shaped bricks in the tunnel in a stacked manner. When laying the special-shaped bricks, ensure that the length of the special-shaped bricks is along the thickness of the wall, so that the pressure-bearing direction of the special-shaped bricks is the length direction. The contact end 1 is connected to the contact end 1, and the inner end 2 is connected to the inner end 2. Since the contact end 1 is large and the inner end 2 is small, the special-shaped bricks of this application will naturally form the following shape after the masonry is completed. Figure 2 The arch structure shown. It is necessary to ensure that the contact end 1 is facing the goaf during masonry, that is, to ensure that the convex side of the arch structure is facing the goaf after the masonry is completed. The stacking masonry is adopted. After the first layer of special-shaped bricks is laid flat, a layer of cement mortar is applied on it, and the second layer of special-shaped bricks is laid flat. The work is repeated alternately until the retaining wall is completed. After completion, the water is exuded to fill the retaining wall structure. Figure 1 It is worth noting that a grouting port for conveying phosphogypsum slurry needs to be reserved at the upper end of the retaining wall.

[0026] Step 3: prepare phosphogypsum slurry, mix water and phosphogypsum to obtain phosphogypsum slurry, ensure the fluidity of the phosphogypsum slurry, and increase the amount of water.

[0027] Step 4: Initial phosphogypsum backfilling: Use a pipe to transport the phosphogypsum slurry through the grouting port above the retaining wall to the goaf inside the retaining wall for filling. It is worth noting that the edges of the pipe and the grouting port are sealed with mortar.

[0028] Step 5, sedimentation. After the first filling, sedimentation is required. When the water flows out through the retaining wall, the phosphogypsum quickly settles to the bottom of the tunnel to form a backfill gypsum layer. Due to the high moisture content, it becomes denser after sedimentation. When the surface of the gypsum layer dries and cracks, the sedimentation ends.

[0029] Step 6: Repeat phosphogypsum backfilling and precipitation: After the first precipitation is completed, fill the phosphogypsum slurry again and precipitate again.

[0030] Step 7: After sealing the wall and filling the phosphoric acid paste slurry for the last time and settling, the precipitated phosphogypsum layer completely fills the goaf, cut the slurry pipeline, and use special-shaped bricks and mortar to seal the grouting port above the retaining wall to fill the water seepage.

[0031] Example 2 The difference between Example 2 and Example 1 is that the hollow structure of the special-shaped brick in Example 2 is an elliptical groove. When pressing the special-shaped brick, the inner right angle enclosed by the pressure-bearing edges is directly changed to a rounded corner, so that the hollow structure of the special-shaped brick formed by pressing forms an elliptical groove, and three groups of hollow structures are also provided, and their distribution is consistent with Example 2, and their size also decreases successively from the contact end to the inward end of the special-shaped brick.

[0032] The above is only an embodiment of the present invention, and the common knowledge such as the specific structure and characteristics of the scheme is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A water seepage backfill retaining wall structure, comprising a wall disposed in a backfill mining tunnel, characterized in that: The wall is an arched structure built with special-shaped bricks. The special-shaped bricks are wedge-shaped structures with a large size at one end and a small size at the other end. Several pressure-bearing edges are constructed on the surface of the special-shaped bricks, and the pressure-bearing edges together form several hollow structures. The convex side of the wall arched structure faces the goaf side, and the arch feet of the wall arched structure are directly connected to the rock masses on both sides. The special-shaped bricks are extruded and formed by 3-8 mm melon stones and cementitious materials.

2. The water-filled retaining wall structure according to claim 1, characterized in that: The strength of the special-shaped bricks in the middle of the wall in the height direction is higher than that of the special-shaped bricks at the bottom.

3. The water-filled retaining wall structure according to claim 2, characterized in that: The hollow structure on the special-shaped brick is also a wedge-shaped structure with one end having a larger size and the other end having a smaller size, and the wedge-shaped direction is consistent with that of the special-shaped brick.

4. The water seepage filling retaining wall structure according to claim 1, characterized in that: The gelling material is a hydraulic gelling material.

5. The water-filled retaining wall structure according to claim 4, characterized in that: The hydraulic cementitious material is a mixed cementitious material of high-temperature calcined phosphogypsum, glass fiber, mineral powder and cement.

6. The water-filled retaining wall structure according to claim 2, characterized in that: The hollow structure on the special-shaped brick is an elliptical groove, and the size of the hollow structure decreases in sequence along the wedge direction from large to small of the special-shaped brick.

7. A method for backfilling phosphogypsum using the water-filled retaining wall structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Select the retaining wall construction location and hoist the special-shaped bricks to the retaining wall construction location for preparation; Step 2: Connect the contact ends of the special-shaped bricks to the contact ends, and connect the inward ends to the inward ends to build a stacked masonry to form a filling retaining wall structure with an arched structure facing the goaf. A grouting port must be reserved above the filling retaining wall structure. Step 3: mixing water and phosphogypsum to obtain phosphogypsum slurry; Step 4: Using a pipeline, transport the phosphogypsum slurry to the goaf in the retaining wall for filling; Step 5: After filling, allow the water to settle and flow out through the retaining wall: Step 6: After the precipitation is completed, repeat steps 4 and 5 to perform cyclic filling and precipitation; Step 7: When the precipitated phosphate paste layer completely fills the goaf, use special-shaped bricks and mortar to seal the grouting opening above the retaining wall.

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