Full-filling grouting process for goaf

Abstract

The invention relates to the technical field of highway construction, in particular to a full-filling grouting process for a goaf, which comprises the following steps of: drilling to form a hole in a reducing manner, mounting a lower grouting pipe with a flange plate, filling gravels and clay, injecting cement paste, casting an orifice pipe, removing the upper grouting pipe after the grout is solidified and formed, and grouting the goaf through the lower grouting pipe. According to the method, the overlying strata are reliably supported and prevented from further caving through a firm filling body formed by drilling holes in the ground surface of an overlying strata area and grouting, the stability and the bearing capacity of an underground structure are enhanced, safety and stability of an upper structure are guaranteed, and the method is suitable for goaf treatment.

Description

Technical Field

[0001] The invention relates to the technical field of highway construction, in particular to a full-filling grouting process for a goaf area. Background Art

[0002] With the mining of coal mines, the surrounding geological environment conditions have been destroyed, and the serious geological disaster problem brought about is the mining collapse and its associated ground fissures; the second is the collapse causing slope instability, and the rainy season often induces the occurrence of slope disasters such as collapse and landslides. The formation of the mining area will change the underground geological structure, leading to changes in the flow path of groundwater and a decrease in the groundwater level. If the foundation of the road is located near the mining area, the formation of the mining area may cause the foundation to be unstable, affecting the construction of the structure above it and the roadbed filling.

[0003] Given that goafs bring a series of uncertainties and risks to road construction, control measures need to be taken to ensure the quality and safety of road construction. The commonly used method for controlling goafs is grouting, which injects grouting materials into underground structures or strata through pipes to enhance their bearing capacity and stability. The traditional grouting method has the following shortcomings: 1) Deep goafs may require grouting materials with higher compressive strength and water resistance; 2) When controlling goafs, especially multi-layer goafs, the depth does not allow the grouting materials to fully fill the voids; 3) There may be weak interlayers between multi-layer goafs, and the uneven pressure on the orifice pipes near the interlayers will affect the grouting effect. The above are the limitations of the traditional grouting method in construction. Summary of the invention

[0004] In view of the above problems, the present invention discloses a full-filling grouting process for goaf areas, comprising the following steps:

[0005] Drilling a hole on the loose bedrock on the surface of the goaf with a drilling rig, and after drilling to a depth of bedrock greater than or equal to 1.0 m to form a first borehole, replacing the drill bit to continue drilling from the bottom of the first borehole to the caving zone of the goaf to form a second borehole, the diameter of the second borehole is smaller than the diameter of the first borehole, and the first borehole and the second borehole form a T-shaped step hole;

[0006] A grouting pipe structure is provided, wherein the grouting pipe comprises a lower grouting pipe and an upper grouting pipe connected to the lower grouting pipe, a reverse thread sleeve is fixedly arranged at the top of the lower grouting pipe, the upper grouting pipe is threadedly connected to the reverse thread sleeve, and a flange tray is sleeved and fixed to the lower grouting pipe at a distance of 200 to 300 mm from the bottom end;

[0007] Put the grouting pipe structure fixed with the flange tray into the T-shaped step hole, and the flange tray is located at the step of the T-shaped step hole;

[0008] Filling gravel and clay into the holes of the flange tray and then injecting cement slurry to seal the holes of the flange tray;

[0009] Pouring a grouting liquid between the outer wall of the grouting pipe structure and the inner wall of the first borehole, and removing the upper grouting pipe after the grouting liquid is solidified;

[0010] Grouting liquid is poured into the goaf through the lower grouting pipe.

[0011] In some of the embodiments, the reverse wire sleeve is 3-10m away from the flange disc.

[0012] In some of the embodiments, the upper grouting pipe and the lower grouting pipe are both steel pipes.

[0013] In some embodiments, the diameter of the flange is 120-130 mm.

[0014] In some of the embodiments, the ratio of cement to fly ash in the preparation of the grouting liquid is 0.5:1, and 2-4% of water glass by weight of cement is added to the grouting liquid.

[0015] In some of the embodiments, 3% water glass by weight of cement is added to the grouting liquid.

[0016] In some of the embodiments, the grouting liquid and the grout stopping liquid are made of the same material.

[0017] In some embodiments, the diameter of the first borehole is 127-133 mm, and the diameter of the second borehole is 89-91 mm.

[0018] The above-mentioned grouting liquid is prepared with a water-cement ratio of 0.5:1 and 3% water glass by weight of cement is added to increase the viscosity of the grouting liquid and reduce the flow range, avoiding unnecessary slurry waste and environmental pollution, while ensuring construction quality.

[0019] Compared with the prior art, the present invention has one of the following advantages or beneficial effects:

[0020] 1. In the full-filling grouting process for goaf areas disclosed in the present invention, after the slurry reaches a certain strength, the upper grouting pipe can be reversed, pulled out and reused, thereby saving raw materials.

[0021] 2. The full-filling grouting process of the goaf disclosed in the present invention can fill the goaf into a solid geological body, improve the overall strength and stability of the geological body, reduce the probability of geological disasters, and enhance the bearing capacity and stability of the foundation, which is beneficial to the subsequent engineering construction of the goaf; the method can also effectively reduce the penetration of slurry during the grouting process, prevent the impact on the surface and groundwater environment, and thus reduce the damage to the environmental water and soil resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By reading the accompanying drawings, the innovation, construction process and advantages of the full-fill pressure grouting method of the present invention can be more intuitively understood. The same symbols in all the drawings refer to the same things. This figure is not drawn according to the true scale, and is intended to illustrate and help understand the innovation of the present invention.

[0023] Figure 1 Flow chart of the full filling grouting process of the goaf in the embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of variable diameter hole formation in the full filling grouting process of the goaf in an embodiment of the present invention;

[0025] Figure 3 It is a schematic diagram of orifice pipe pouring in the full-fill grouting process of the goaf in an embodiment of the present invention;

[0026] Figure 4 for Figure 2 Schematic diagram of the reverse wire interface at A in the middle;

[0027] Figure 5 A top view of the flange at position B in an embodiment of the present invention;

[0028] Among them: 1 is the loose bedrock on the surface; 2 is the upper goaf; 3 is the caving zone in the goaf; 4 is the first borehole; 5 is the second borehole; 6 is the grouting stop zone; 7 is the grouting pipe structure. DETAILED DESCRIPTION

[0029] The structure of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to limit the present invention.

[0030] like Figure 1 As shown, this embodiment discloses a full-filling grouting process for goaf, which can be applied to grouting of two or more goafs. In this embodiment, two goafs are taken as an example for explanation, and the two goafs are respectively a goaf caving zone 3 and an upper goaf 2; specifically, the method comprises the following steps:

[0031] Step S1, such as Figure 2As shown, a drilling rig is used to drill a hole in the loose bedrock 1 on the surface of the goaf, and after drilling to a depth of the bedrock greater than or equal to 1.0 m to form a first borehole 4, the drill bit is replaced to continue drilling from the bottom of the first borehole 4 to the caving zone 3 of the goaf to form a second borehole 5, the diameter of the second borehole 5 is smaller than the diameter of the first borehole 4, and the first borehole 4 and the second borehole 5 form a T-shaped step hole; the diameter of the first borehole 4 is 127-133 mm, and the diameter of the second borehole 5 is 89-91 mm.

[0032] Specifically, the drilling rig uses a 127mm drill bit to start drilling. The diameter of the first borehole 4 formed by drilling in the loose bedrock 1 on the surface is about 130mm. After the drilling depth to the bedrock reaches 1.0m, the drill bit is replaced and the diameter is changed to 89mm. For the goaf, in principle, the hole is drilled once, and the second borehole 5 is formed by drilling to a final hole 0.5m inside the caving zone 3 of the goaf.

[0033] Step S2, providing a grouting pipe structure 7, wherein the grouting pipe comprises a lower grouting pipe and an upper grouting pipe connected to the lower grouting pipe, and a reverse wire sleeve is fixedly provided at the top of the lower grouting pipe. Figure 4 The diagram is a schematic diagram of the connection between the upper grouting pipe and the reverse thread casing. The reverse thread casing is 3-10mm away from the flange disc. The upper grouting pipe is threadedly connected to the reverse thread casing, and the lower grouting pipe is welded and fixed with a flange tray at a distance of 200-300mm from the bottom. Specifically, the appropriate type of flange is selected according to the size of the hole and the size of the grouting pipe. Figure 5 A top view of the flange plate.

[0034] Specifically, the upper grouting pipe and the lower grouting pipe are both steel pipes, the flange is circular, and the diameter of the flange is 120-130 mm.

[0035] Step S3, such as Figure 3 As shown, the grouting pipe structure 7 with the flange tray fixed thereto is placed into the T-shaped step hole, and the flange tray is located at the step of the T-shaped step hole.

[0036] Step S4, filling gravel and clay into the holes of the flange tray and then injecting cement slurry to seal the holes of the flange tray.

[0037] Step S5, pour grouting liquid between the outer wall of the grouting pipe structure 7 and the inner wall of the first borehole 4 to form a grouting zone 6 between the grouting pipe structure 7 and the first borehole 4, and after the grouting liquid is solidified and formed, reversely screw the upper grouting pipe and remove it to prepare for reuse when casting other orifice pipes. The orifice pipe casting thickness is consistent with the drilling depth before the diameter change, which can ensure that the upper weak rock layer will not collapse, leak, or pollute during the grouting process. In addition, it can also isolate surface water and prevent groundwater pollution.

[0038] Specifically, the ratio of cement to fly ash is 0.5:1 when preparing the grouting liquid, and 3% water glass by weight of cement is added to the grouting liquid to increase the viscosity of the grouting liquid and reduce the flow range, avoiding unnecessary slurry waste and environmental pollution, while ensuring construction quality.

[0039] Step S6, pouring grouting liquid into the goaf through the lower grouting pipe, and the pouring is terminated when the cavity is filled; specifically, the grouting liquid and the stop grouting liquid are made of the same material.

[0040] In summary, the full-filling grouting process of the present invention is highly targeted, safe and reliable to use, simple to manufacture and use, and economical. It reduces the possibility of collapse of the upper loose bedrock during grouting, and can also effectively reduce the penetration of slurry during the grouting process, prevent the impact on the surface and groundwater environment, and reduce the damage to environmental water and soil resources. This method can be widely used in the management of goaf areas in the field of highway construction technology, which can improve the stability of the foundation, reduce the occurrence of geological disasters, protect the water and soil resources environment, and also realize the recycling of engineering materials.

[0041] Those skilled in the art can implement variations by combining the prior art with the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0042] The above is a description of the embodiments of the present invention. It should be clear that the present invention is not limited to the above-mentioned specific implementation methods. Equipment and structures not described in detail should be implemented in a common manner in the art. Any technician familiar with the art can make various possible changes and modifications according to the methods and technical contents disclosed above, or modify them into equivalent embodiments without departing from the technical solution of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments, as long as they do not deviate from the core of the technical solution of the present invention, still belong to the protection scope of the technical solution of the present invention.

Claims

1. A full-fill grouting process for goaf, characterized in that: The steps include: Drilling a hole on the loose bedrock on the surface of the goaf with a drilling rig, and after drilling to a depth of bedrock greater than or equal to 1.0 m to form a first borehole, replacing the drill bit to continue drilling from the bottom of the first borehole to the caving zone of the goaf to form a second borehole, the diameter of the second borehole is smaller than the diameter of the first borehole, and the first borehole and the second borehole form a T-shaped step hole; A grouting pipe structure is provided, wherein the grouting pipe comprises a lower grouting pipe and an upper grouting pipe connected to the lower grouting pipe, a reverse thread sleeve is fixedly arranged at the top of the lower grouting pipe, the upper grouting pipe is threadedly connected to the reverse thread sleeve, and a flange tray is sleeved and fixed to the lower grouting pipe at a distance of 200 to 300 mm from the bottom end; Put the grouting pipe structure fixed with the flange tray into the T-shaped step hole, and the flange tray is located at the step of the T-shaped step hole; Filling gravel and clay into the holes of the flange tray and then injecting cement slurry to seal the holes of the flange tray; Pouring a grouting liquid between the outer wall of the grouting pipe structure and the inner wall of the first borehole, and removing the upper grouting pipe after the grouting liquid is solidified; Grouting liquid is poured into the goaf through the lower grouting pipe.

2. The full filling grouting process for goaf as claimed in claim 1, characterized in that: The reverse wire sleeve is 3-10m away from the flange disc.

3. The full filling grouting process for goaf as claimed in claim 1, characterized in that: The upper grouting pipe and the lower grouting pipe are both steel pipes.

4. The full-fill grouting process for goaf as claimed in claim 1, characterized in that: The diameter of the flange is 120-130 mm.

5. The full filling grouting process for goaf according to claim 1, characterized in that: When the grout-stopping liquid is prepared, the ratio of cement to fly ash is 0.5:1, and water glass in an amount of 2-4% by weight of cement is added to the grout-stopping liquid.

6. The full-fill grouting process for goaf as claimed in claim 5, characterized in that: 3% of water glass by weight of cement is added into the grout-stopping liquid.

7. The full-fill grouting process for goaf according to claim 1, characterized in that: The grouting liquid and the grout stopping liquid are made of the same material.

8. The full filling grouting process for goaf as claimed in claim 1, characterized in that: The diameter of the first borehole is 127-133 mm, and the diameter of the second borehole is 89-91 mm.

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