Full-solid-waste-based artificial pillar supporting structure and construction method

Abstract

The invention belongs to the technical field of underground mine roadway supporting, and provides an all-solid-waste-based artificial pillar supporting structure and a construction method, and the construction method comprises the following construction steps: S1, sealing and fixing a flexible mold bag on a roadway bottom plate; s2, solid-state raw materials of the solid-waste-based filling body are stacked in a flexible mold bag layer by layer, and a reinforcing grid is adopted to restrain a stacking body of the solid-state raw materials till the stacking body of the solid-state raw materials abuts against a roadway top plate; s3, the reinforcing grid is wrapped with a flexible mold bag, and the flexible mold bag and the roadway roof are sealed; and S4, a liquid raw material of the solid waste-based filling body is poured into the flexible mold bag through a grouting opening in the top of the flexible mold bag till the flexible mold bag is full of the liquid raw material, and the solid waste-based filling body is formed after the liquid raw material and the solid raw material are solidified. The coal pillar-free gob-side entry retaining method can achieve coal pillar-free gob-side entry retaining so as to improve the safety performance of the roadway and achieve the purposes of solving the problems that in the underground mining process, roadway supporting flexibility is poor, solid waste is difficult to treat, and cost is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground mine tunnel support, and in particular relates to a fully solid waste-based artificial pillar support structure and a construction method. Background Art

[0002] Gob-side entry retention is a pillar-free mining technique that utilizes various types of tunnel support structures to reduce resource waste caused by retaining coal pillars. The stable tunnel structure facilitates the transportation of raw coal, equipment, and personnel safety. Currently, support structures include side-of-the-road support structures such as waste rock walls, waste rock belts, wood piles, and roadside backfill, as well as in-road support technologies such as anchor bolts, cables, and wood and steel scaffolding. These structures reinforce and stabilize the overburden, the roadway roof and floor, and the sides. However, existing technologies all suffer from varying degrees of high cost and complex processes.

[0003] The massive accumulation of solid waste not only consumes significant land resources but also poses serious environmental pollution and safety risks. Directly using solid wastes such as gangue, tailings, and industrial slag for backfill can significantly reduce the need for these wastes, reduce the land area occupied by these wastes, and alleviate the pressure on land resources. With the rapid development of the economy and the construction industry, the demand for cement has gradually increased. However, cement production not only consumes a large amount of resources but also produces a large amount of CO2. Therefore, there is an urgent need to explore alternatives to cement to reduce carbon emissions. Alkali-activated materials, a new type of green building material, are prepared from amorphous aluminosilicate powder using an alkaline activator. Solid wastes such as blast furnace slag and fly ash can completely replace cement. Alkali-activated materials exhibit excellent fluidity, stability, and high early strength. All-solid waste-based backfill materials can reduce carbon emissions, achieve resource utilization, and render solid waste harmless, providing a new solution for tunnel grouting support.

[0004] In recent years, artificial pillars have been widely used in the technology of coal-pillar-free mining along the goaf. For example, the invention patent with application number 200910021105.4 discloses a flexible formwork membrane tube, rigid bracket and concrete combined support system and construction method. The support system consists of flexible formwork cloth, anchor rods, steel mesh and sprayed concrete. Its construction method is to make a flexible formwork membrane, extend the flexible formwork membrane tube, install a grid, install anchor rods through the reserved holes of the flexible formwork membrane tube, and spray concrete to close the grid. For example, the invention patent with application number 202111434726.2 discloses a reinforced concrete artificial pillar construction method. Its construction method is to prefabricate units of equal height, assemble the prefabricated units in an inverted manner from top to bottom, fix the prefabricated units connected to the top of the goaf with anchor cable components, and the next prefabricated unit adjacent to the top prefabricated unit is detachably connected to the lower end of the anchor cable component through a connecting rod component.

[0005] The artificial pillars involved in the above schemes all include anchor rods / anchor cables and concrete. The support system is relatively complex, and a large amount of cement and natural aggregate are used in the preparation process of concrete, which cannot meet the requirements of simple and green construction of artificial pillars. Summary of the Invention

[0006] The purpose of the present invention is to provide a fully solid waste-based artificial pillar support structure and construction method to solve the above problems, realize coal pillar-free goaf-side tunneling, improve the safety performance of the tunnel, and achieve the purpose of solving the problems of poor tunnel support flexibility, difficult solid waste treatment, and high cost during underground mining.

[0007] To achieve the above objectives, the present invention provides the following solution: a fully solid waste-based artificial pillar support structure, comprising:

[0008] A reinforcement grid, wherein the top and bottom of the reinforcement grid respectively abut against the top and bottom of the roadway, the outer side of the reinforcement grid is wrapped with a flexible mold bag, and the top of the flexible mold bag is provided with a grouting port;

[0009] A solid waste-based filling body is filled in the reinforcement grid.

[0010] Preferably, the raw materials of the solid waste-based filling body include at least coarse aggregate and alkali-activated silica-alumina solid waste grouting material.

[0011] A fully solid waste-based artificial pillar support construction method, the construction steps include:

[0012] S1. Seal and fix the flexible mold bag on the tunnel floor;

[0013] S2. stacking the solid raw materials of the solid waste-based filling body layer by layer in a flexible mold bag, and restraining the accumulation of the solid raw materials with a reinforcement grid until the accumulation of the solid raw materials abuts against the roadway roof;

[0014] S3. Wrap the reinforcement grid with a flexible mold bag and seal it with the tunnel roof;

[0015] S4. Use the grouting port on the top of the flexible mold bag to pour the liquid raw material of the solid waste-based filling body into the flexible mold bag until the flexible mold bag is full, wherein the liquid raw material and the solid raw material solidify to form the solid waste-based filling body.

[0016] Preferably, the solid raw material is coarse aggregate, and S2 comprises:

[0017] The coarse aggregate is stacked layer by layer in a flexible mold bag, and a reinforcement grid is used to constrain the accumulation of the coarse aggregate until the accumulation of the coarse aggregate abuts against the roadway roof.

[0018] Preferably, the liquid raw material is alkali-activated silica-alumina solid waste grouting material, and S4 includes:

[0019] The alkali-activated silico-alumina solid waste grouting material is poured into the flexible mold bag through the grouting port on the top of the flexible mold bag until the flexible mold bag is full, wherein the alkali-activated silico-alumina solid waste grouting material and the coarse aggregate form the solid waste-based filling body after solidification.

[0020] Preferably, in step S1, the flexible mold bag is made of high-strength, low-elongation synthetic fiber filaments.

[0021] Preferably, the coarse aggregate comprises discontinuously graded coal gangue, other crushed stone or large-sized waste slag;

[0022] The particle size of coarse aggregate should be greater than 20mm.

[0023] Preferably, the reinforcement grid is made of fiber fabric or metal material;

[0024] The mesh size of the reinforcement mesh shall not exceed 20 mm.

[0025] Preferably, the alkali-activated silica-alumina solid waste grouting material consists of a precursor, fine aggregate and an alkali activator;

[0026] The precursor is metal smelting slag, the fine aggregate includes tailings sand and multi-level coal gangue, and the alkali activator includes sodium hydroxide / potassium and sodium / potassium silicate, which are used to activate the gelling activity of silicoaluminous solid waste.

[0027] Preferably, the maximum particle size of the fine aggregate does not exceed 2.36 mm.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] (1) The artificial pillar support structure of the present invention directly uses coal gangue, other crushed stone, or large-sized waste slag as coarse aggregate and tailings sand as fine aggregate, which can significantly reduce the storage requirements of these wastes, reduce the land area occupied by the storage yard, and alleviate the pressure on land resources. Compared with natural fillers (such as sand and gravel), the cost is lower, which can significantly reduce the purchase and transportation costs of fillers.

[0030] (2) The artificial pillar support structure of the present invention uses alkali-activated silicoaluminous solid waste material as filling grouting material, which can effectively reduce the pollution of solid waste to the environment. The alkali-activated silicoaluminous solid waste grouting material has the characteristics of high fluidity and stability. Under the action of gravity, it can rely on its own fluidity to fill the aggregate skeleton. The construction is efficient and convenient, which can reduce the construction cost of artificial pillars. In addition, the alkali-activated silicoaluminous solid waste grouting material has high early strength and can meet the requirements of pillar-free mining technology.

[0031] (3) The all-solid waste-based artificial pillar support construction method of the present invention has a simple overall process layout, reduces labor, is highly efficient, and has high final pillar support strength. It can achieve coal pillar-free goaf-side lane retention and has great application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 Schematic diagram of the artificial pillar support structure of the present invention;

[0034] Among them, 1. Flexible mold bag; 2. Reinforcement grid; 3. Solid waste-based filling body. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1:

[0038] Reference Figure 1 The present invention provides a fully solid waste-based artificial pillar support structure, comprising:

[0039] A reinforcement grid 2, the top and bottom of the reinforcement grid 2 respectively abut against the top and bottom of the roadway, the outer side of the reinforcement grid 2 is wrapped with a flexible mold bag 1, and a grouting port is opened on the top of the flexible mold bag 1;

[0040] The solid waste-based filling body 3 is filled in the reinforcement grid 2 .

[0041] According to a further optimization scheme, the raw materials of the solid waste-based filling body 3 include at least coarse aggregate and alkali-activated silica-alumina solid waste grouting material.

[0042] A fully solid waste-based artificial pillar support construction method, the construction steps include:

[0043] S1, sealing and fixing the flexible mold bag 1 on the tunnel floor;

[0044] S2, stacking the solid raw materials of the solid waste-based filling body 3 layer by layer in the flexible mold bag 1, and using the reinforcement grid 2 to constrain the accumulation of the solid raw materials until the accumulation of the solid raw materials abuts against the tunnel roof;

[0045] Specifically, the aggregate accumulation body is constrained by the reinforcement grid 2 and raised layer by layer until the top plate of the roadway, thereby forming a columnar aggregate accumulation body constrained by the reinforcement grid 2 .

[0046] S3, using the flexible mold bag 1 to wrap the reinforcement grid 2 and seal it with the tunnel roof;

[0047] Specifically, the flexible mold bag 1 is lifted up and fixed on the tunnel roof and sealed with the tunnel roof. At this time, it is necessary to ensure that the grouting port is located at the top of the side wall of the columnar aggregate accumulation body.

[0048] S4. Use the grouting port on the top of the flexible mold bag 1 to pour the liquid raw material of the solid waste-based filling body 3 into the flexible mold bag 1 until the flexible mold bag 1 is full, wherein the liquid raw material and the solid raw material solidify to form the solid waste-based filling body 3.

[0049] After the flexible mold bag 1 is filled with alkali-activated silicon-aluminum solid waste grouting material, the grouting port is closed.

[0050] Further optimization scheme, solid raw materials are coarse aggregate, S2 includes:

[0051] Coarse aggregates are stacked layer by layer in the flexible mold bag 1, and the reinforcement grid 2 is used to constrain the accumulation of coarse aggregates until the accumulation of coarse aggregates abuts against the roadway roof.

[0052] Further optimization scheme, the liquid raw material is alkali activated silicon aluminum solid waste grouting material, S4 includes:

[0053] Alkali-activated silica-alumina solid waste grouting material is poured into the flexible mold bag 1 through the grouting port on the top of the flexible mold bag 1 until the flexible mold bag 1 is full, wherein the alkali-activated silica-alumina solid waste grouting material and the coarse aggregate form a solid waste-based filling body 3 after solidification.

[0054] According to a further optimized solution, in step S1 , the flexible mold bag 1 is made of high-strength and low-elongation synthetic fiber filaments.

[0055] In this embodiment, the flexible mold bag 1 can be made of high-strength, low-elongation synthetic fiber filaments such as polypropylene and polyester, which are impermeable and have high strength. It can withstand the head pressure generated by the weight of the grouting material before it solidifies at a height of 3.5 meters and the lateral pressure applied to the flexible mold bag.

[0056] To further optimize the solution, the coarse aggregate includes discontinuously graded coal gangue, other crushed stone or large-sized waste slag;

[0057] The particle size of coarse aggregate should be greater than 20mm.

[0058] In actual construction, the composition of coarse aggregate includes but is not limited to discontinuously graded coal gangue, other crushed stone or large-sized waste slag.

[0059] Further optimizing the solution, the reinforcement grid 2 is made of fiber fabric or metal material;

[0060] The mesh size of the reinforcement mesh 2 is not greater than 20 mm.

[0061] In this embodiment, the material of the reinforcement grid 2 is polyvinyl chloride, and the grid size is 20 mm.

[0062] Further optimizing the scheme, the alkali activated silica-alumina solid waste grouting material is composed of precursor, fine aggregate and alkali activator;

[0063] The precursor is metal smelting slag, the fine aggregate includes tailings sand and multi-grade coal gangue, and the alkaline activator includes sodium / potassium hydroxide and sodium / potassium silicate, which are used to activate the gelling activity of siliceous and aluminous solid waste.

[0064] In a further optimized solution, the components of the precursor include but are not limited to slag, fly ash, calcined coal gangue or other metal smelting slag.

[0065] In this embodiment, the alkali activator is sodium hydroxide with a purity of not less than 98% and a water glass solution with a modulus of 3.3, Na2O and SiO2 contents of 8.53% and 26.98% respectively, an alkali content of 6%, and a modulus of 1.

[0066] The alkali-activated silica-alumina solid waste grouting material has the characteristics of high fluidity. Under the action of gravity, it can rely on its own fluidity to fill the columnar aggregate accumulation constrained by the reinforcement grid 2. The slump expansion value is not less than 250mm, the cohesion is good, and no segregation or water seepage occurs in a static state.

[0067] According to the further optimization plan, the maximum particle size of fine aggregate does not exceed 2.36mm.

[0068] The plan is further optimized, and the particle size of the tailings sand is less than 2mm.

[0069] Example 2:

[0070] This embodiment differs from the first embodiment in that the reinforcement grid is made of iron, and other conditions remain unchanged.

[0071] Example 3:

[0072] The difference between this embodiment and the first embodiment is that the particle size of the coal gangue is 25 to 30 mm, and other conditions remain unchanged.

[0073] Example 4

[0074] This embodiment is different from the first embodiment in that the precursors of the alkali-activated silicoaluminous solid waste grouting material are slag and fly ash, wherein the mass ratio of slag to fly ash is 7:3, and other conditions remain unchanged.

[0075] The artificial pillars prepared in Examples 1 to 4 were subjected to performance tests on a triaxial creep testing machine. During the creep test, the confining pressure σ2=σ3=1 MPa was set, and the axial pressure σ1 was set using a graded loading method. The results are shown in Table 1.

[0076] Table 1 Creep test data of the embodiment of artificial pillar support structure

[0077] Serial number Creep rupture strength (MPa) Creep failure strain ε(%) 1 41.2 1.924 2 51.4 1.153 3 45.3 1.432 4 36.7 1.716

[0078] Experiments have shown that different reinforcement grid materials, grouting materials, and coal gangue particle sizes have different effects on the artificial pillars, according to the fully solid waste-based artificial pillar support structure and its construction method provided in this article. The following situations can be used for reference:

[0079] (1) Compared with polyvinyl chloride, when the material of the reinforcement grid 2 is iron, the artificial pillar has significantly higher creep failure strength and lower creep failure strain.

[0080] (2) Artificial pillars prepared with larger coal gangue particle size have higher creep failure strength and lower creep failure strain.

[0081] (3) When 30% fly ash is added to the grouting material, the creep failure strength of the artificial pillar decreases and the creep failure strain increases.

[0082] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0083] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A fully solid waste-based artificial pillar support structure, characterized in that ,include: A reinforcement grid (2), wherein the top and bottom of the reinforcement grid (2) are respectively in contact with the top and bottom of the tunnel, the outer side of the reinforcement grid (2) is wrapped with a flexible mold bag (1), and the top of the flexible mold bag (1) is provided with a grouting port; A solid waste-based filling body (3), wherein the solid waste-based filling body (3) is filled in the reinforcement grid (2).

2. The all-solid waste-based artificial pillar support structure according to claim 1, characterized in that: The raw materials of the solid waste-based filling body (3) include at least coarse aggregate and alkali-activated silica-alumina solid waste grouting material.

3. A fully solid waste-based artificial pillar support construction method, based on the fully solid waste-based artificial pillar support structure according to claim 1 or 2, characterized in that , the construction steps include: S1, sealing and fixing the flexible mold bag (1) on the tunnel floor; S2, stacking the solid raw materials of the solid waste-based filling body (3) layer by layer in the flexible mold bag (1), and using the reinforcement grid (2) to constrain the accumulation of the solid raw materials until the accumulation of the solid raw materials abuts against the tunnel roof; S3, using a flexible mold bag (1) to wrap the reinforcement grid (2) and seal it with the tunnel roof; S4. Use the grouting port at the top of the flexible mold bag (1) to pour the liquid raw material of the solid waste-based filling body (3) into the flexible mold bag (1) until the flexible mold bag (1) is filled, wherein the liquid raw material and the solid raw material solidify to form the solid waste-based filling body (3).

4. The all-solid waste-based artificial pillar support construction method according to claim 3 is characterized by: The solid raw material is coarse aggregate, and S2 includes: The coarse aggregate is stacked layer by layer in a flexible mold bag (1), and a reinforcement grid (2) is used to constrain the accumulation of the coarse aggregate until the accumulation of the coarse aggregate abuts against the roadway roof.

5. The all-solid waste-based artificial pillar support construction method according to claim 4 is characterized in that: The liquid raw material is an alkali-activated silicon-alumina solid waste grouting material, and S4 includes: The alkali-activated silico-alumina solid waste grouting material is poured into the flexible mold bag (1) using the grouting port at the top of the flexible mold bag (1) until the flexible mold bag (1) is filled, wherein the alkali-activated silico-alumina solid waste grouting material and the coarse aggregate solidify to form the solid waste-based filling body (3).

6. The all-solid waste-based artificial pillar support construction method according to claim 3 is characterized by: In step S1, the flexible mold bag (1) is made of high-strength and low-elongation synthetic fiber filaments.

7. The all-solid waste-based artificial pillar support construction method according to claim 4 is characterized by: The coarse aggregate includes discontinuously graded coal gangue, other crushed stone or large-sized waste slag; The particle size of coarse aggregate should be greater than 20mm.

8. The all-solid waste-based artificial pillar support construction method according to claim 3 is characterized by: The reinforcement grid (2) is made of fiber fabric or metal material; The mesh size of the reinforcement mesh (2) is not greater than 20 mm.

9. The all-solid waste-based artificial pillar support construction method according to claim 5, characterized in that: The alkali-activated silica-alumina solid waste grouting material is composed of a precursor, fine aggregate and an alkali activator; The precursor is metal smelting slag, the fine aggregate includes tailings sand and multi-level coal gangue, and the alkali activator includes sodium hydroxide / potassium and sodium / potassium silicate, which are used to activate the gelling activity of silicoaluminous solid waste.

10. The all-solid waste-based artificial pillar support construction method according to claim 9, characterized in that: The maximum particle size of the fine aggregate does not exceed 2.36 mm.

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