Bead-shaped karst cave separation grouting structure and construction method

Abstract

The construction method comprises the construction steps that after drilling of the bead-shaped karst cave is completed, a lower grouting pipe and a partition structure on the lower grouting pipe stop descending when the lower grouting pipe and the partition structure descend to a lower-layer karst cave top plate, a water injection pipe injects water into a bag for pressurization, and the bag structure is expanded to make contact with the hole wall of a drilled hole; then, grouting is conducted, the grouting pipe is lifted up step by step, and grouting is conducted on the lower-layer karst cave; after the lower-layer karst cave is grouted and filled compactly, a water injection pipe valve is opened for pressure relief, so that the bag structure shrinks and is separated from the hole wall of the drill hole; synchronously lifting the grouting pipe to enable the limiting structure at the lower part of the grouting pipe to be in contact with the metal protective sleeve, and then driving the bag integral structure and the water injection pipe to be lifted up along with the grouting pipe until the partition structure is lifted to the top plate of the karst cave of the upper layer; and water injection and pressurization are repeated in the bag, the grouting pipe injects grouting into the karst cave, then pressure relief is conducted, and the bag is lifted to the upper-layer karst cave till grouting treatment of all the karst caves is completed. And the string-bead-shaped karst cave is densely grouted.

Description

Technical Field

[0001] The invention relates to the technical field of underground cave filling and reinforcement, and in particular to a beaded cave partition grouting structure and a construction method. Background Art

[0002] Underground engineering construction is in the ascendant, and is gradually developing towards construction under complex geological conditions; a number of underground projects (such as tunnels and subway stations) are built in areas with developed caves, facing the problems of few cave treatment methods, poor treatment effects, and great difficulty in treatment. Taking the Shenzhen-Huizhou Intercity Dapeng Branch Line as an example, after supplementary survey, a total of 1,072 caves were found in Kwai Chung Station (station length), and 829 caves needed to be treated, most of which were bead-shaped caves. The vertical height of the exposed caves ranged from 0.2 to 19 meters, which greatly increased the difficulty of cave treatment and the risk of station construction.

[0003] At present, when treating beaded caves in the cave development area, because the drilling hole passes through the upper cave to the lower cave, the upper and lower caves are connected, and the position between the two caves is difficult to fill and block densely with shell materials; Figure 4 As shown, when grouting the lower cave, the slurry will flow from the gap between the pipe wall and the hole wall to the upper cave, resulting in the lower cave not being properly grouted, affecting the treatment effect.

[0004] For example, the patent CN111691397A discloses a method for grouting holes for steel pipe piles to fill beaded-type karst caves at the bottom of a karst tunnel, which includes the following steps: Step 1: Karst detection at the bottom of the tunnel, using geological radar to detect the beaded-type karst at the bottom of the tunnel, and for areas where karst is confirmed to exist, geological drilling is used for detection and confirmation to determine the distribution of the beaded-type karst, including the number of caves, the size of the caves, the location of the caves, and the filling conditions of the caves; Step 2: Design of grouting holes for steel pipe piles, determining the grouting parameters for steel pipe piles according to the distribution of the beaded-type karst; the slurry will flow from the connecting holes to the upper caves, resulting in the lower caves not being properly grouted, affecting the treatment effect. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a beaded cave separation grouting structure and a construction method to achieve the purpose of effective grouting and compaction of the beaded cave.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A beaded cave partition grouting structure comprises a grouting pipe for extending into each cave, wherein the grouting pipe is provided with a partition structure for partitioning the communicating gap between adjacent upper and lower caves, and the partition structure is a contractible and deformable bag structure.

[0008] The grouting pipe is provided with limiting structures for protecting the bladder bag above and below the bladder bag structure.

[0009] The bag structure is connected with a water injection pipe.

[0010] The bag structure comprises a bag body and a metal protective shell arranged outside the bag body. The bag body is fixed on the grouting pipe, and the metal protective shell is a group of blade structures that can be opened along with the bag.

[0011] A group of partition structures are arranged at intervals on the grouting pipe.

[0012] The limiting structure is a limiting ring, two limiting rings are fixed on the grouting pipe, and the bag structure is located between the two limiting rings.

[0013] The water injection pipe is provided with a pressure gauge and a control valve.

[0014] The outer layer of the pouch body is provided with a pouch protective cover, and the metal protective shell is a two-part cover shell arranged opposite to each other up and down, and the two parts of the cover shell are respectively fixed on the upper part and the lower part of the pouch protective cover.

[0015] Each of the cover shells is a group of arc-shaped blades arranged in an annular direction.

[0016] A construction method of the beaded cave partition grouting structure comprises the following steps:

[0017] 1) After the beaded cave is drilled, the lower grouting pipe and the partition structure on it are lowered to the top plate of the lower cave, and the lowering is stopped. Water is injected into the bag through the water injection pipe to increase pressure, and the bag protective cover and metal protective shell are stretched open to make them contact with the wall of the drilled hole;

[0018] 2) Then grouting is performed and the grouting pipe is gradually lifted up to grout the lower cave;

[0019] 3) After the lower cave is filled with grouting and compacted, the valve of the water injection pipe is opened to release the pressure, so that the bag loses water, and the bag protective cover and the metal protective shell are out of contact with the borehole wall;

[0020] 4) The grouting pipe is synchronously lifted up so that the lower limiting structure of the grouting pipe contacts the metal protective sleeve, and then the whole bag structure and the water injection pipe are lifted up along with the grouting pipe until the partition structure is lifted to the upper cave roof and then stops;

[0021] 5) Repeatedly inject water into the bag to increase pressure, inject grout into the cave through the grouting pipe, then release the pressure and lift it up to the upper cave until the grouting treatment of all caves is completed.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The beaded cave separation grouting structure and construction method are reasonably designed. The partition structure arranged on the grouting pipe can effectively separate the upper cave of the beaded cave and the lower cave of the beaded cave during grouting. After the lower cave is densely grouted, the upper cave is grouted, which significantly improves the cave treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following is a brief description of the contents and symbols in the drawings of this specification:

[0025] Figure 1 It is a schematic diagram of the partition grouting structure of the present invention.

[0026] Figure 2 It is a schematic diagram of the partition structure of the present invention.

[0027] Figure 3 It is a schematic diagram of the construction process of the present invention.

[0028] Figure 4 This is a schematic diagram of the existing method of cave grouting.

[0029] In the figure:

[0030] 1-grouting pipe, 2-limiting structure, 3-partition structure, 4-water injection pipe, 5-pressure gauge, 6-water injection pipe valve, 7-upper cave of beaded cave, 8-lower cave of beaded cave, 9-grouting filler; 10-drilled hole wall, 31-bladder body, 32-bladder protection cover, 33-metal protection shell. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention will be further explained in detail below through the description of embodiments with reference to the accompanying drawings.

[0032] like Figures 1 to 3 As shown, the beaded cave partition grouting structure includes a grouting pipe 1 for extending into each cave, a partition structure 3 for separating the connecting gaps between adjacent upper and lower caves, and a limiting structure 2 for limiting and protecting the partition structure.

[0033] The partition structure 3 is arranged on the grouting pipe 1 and can be lowered and lifted together with the grouting pipe. The partition structure can block the upper cave 7 and the lower cave 8 of the beaded cave, which can improve the density of the grouting of the lower cave, thereby improving the cave reinforcement effect.

[0034] The partition structure is a bag structure that can be contracted and expanded; a limiting structure 2 for protecting the bag is provided above and below the bag structure on the grouting pipe.

[0035] Furthermore, the limiting structure is a limiting ring, two limiting rings are fixed on the grouting pipe, the bag structure is located between the two limiting rings, and the limiting rings are used to limit and protect the bag structure during the lowering and lifting process.

[0036] A group of partition structures are arranged at intervals on the grouting pipe to improve the construction efficiency. The bag structure is connected with a water injection pipe 4, and a pressure gauge 5 and a control valve 6 are arranged on the water injection pipe to control the water injection pressure, so as to facilitate the control of the expansion or contraction of the bag structure.

[0037] The bag structure includes a bag body 31 and a metal protective shell 33 arranged outside the bag body. The bag body is fixed on the grouting pipe, and the metal protective shell is a group of blade structures that can be opened along with the bag.

[0038] Furthermore, the outer layer of the bladder body is provided with a bladder protective cover 32, and the metal protective shell is a two-part cover shell arranged opposite to each other, and the two parts of the cover shell are respectively fixed on the upper and lower parts of the bladder protective cover; each of the cover shells is a group of arc-shaped blades arranged in a circumferential direction.

[0039] The present invention effectively separates the upper cave of the beaded cave and the lower cave of the beaded cave during grouting by means of the partition structure arranged on the grouting pipe. After the lower cave is densely grouted, the upper cave is grouted, which significantly improves the cave treatment effect.

[0040] The construction method of the beaded cave partition grouting structure of the present invention comprises the following steps:

[0041] 1) After the beaded cave is drilled, the lower grouting pipe and the partition structure on it are lowered to the top plate of the lower cave, and the lowering is stopped. Water is injected into the bag through the water injection pipe to increase pressure, and the bag protective cover and metal protective shell are stretched open to make them contact with the wall of the drilled hole;

[0042] 2) Then grouting is performed and the grouting pipe is gradually lifted up to grout the lower cave;

[0043] 3) After the lower cave grouting filling material 9 is compacted, the water injection pipe valve is opened to release the pressure, so that the bag loses water, and the bag protective cover and the metal protective shell are out of contact with the borehole wall 10;

[0044] 4) The grouting pipe is synchronously lifted up so that the lower limiting structure of the grouting pipe contacts the metal protective sleeve, and then the whole bag structure and the water injection pipe are lifted up along with the grouting pipe until the partition structure is lifted to the upper cave roof and then stops;

[0045] 5) Repeatedly inject water into the bag to increase pressure, inject grout into the cave through the grouting pipe, then release the pressure and lift it up to the upper cave until the grouting treatment of all caves is completed.

[0046] Among them, the limiting structure is a circular ring structure fixed on the grouting pipe. A through hole is provided in the center of the circular ring structure. The grouting pipe passes through the through hole and is connected and fixed by fasteners. Its function is to limit the position of the partition structure, and it can drive the partition structure to move up and down when lifted and lowered.

[0047] There is no fixed connection between the partition structure and the grouting pipe, so that the grouting pipe can move up and down without being constrained, so that the grouting pipe can be gradually lifted and grouted at a layer of 30 to 50 cm; the bag body and the bag belt protective cover are flat in a "◎" structure, and the middle ring is convenient for inserting the grouting pipe. During production, the bag and the bag belt protective cover are put on the grouting pipe, and then the limit is set according to the depth of the cave, the preset partition position, etc.; the bag and the bag belt protective cover can use polyester fiber as the braiding layer material, and the inner / outer covering layer is made of nitrile rubber + PVC, which is a material with a certain ductility, meeting the requirements of opening after water injection and shrinking after pressure relief.

[0048] The bladder body and the bladder protective cover are set to a double-layer structure, the purpose of which is to prevent the borehole wall or the metal protective shell from cutting the bladder when the grouting pipe is lowered / lifted, resulting in water injection failure, thereby affecting the partition effect; the metal protective shell is a thin metal shell structure, divided into upper and lower parts, wrapped on the outside of the bladder protective cover; each part is composed of multiple pieces in a circumferential direction, and after the bladder is opened, each metal protective shell piece is stretched open to contact the borehole wall. The metal protective shell piece and the bladder protective cover are bonded with glue, and the metal protective shell piece can be driven to retract when the bladder is depressurized and contracted.

[0049] Furthermore, the size of the partition structure can be customized according to the diameter of the borehole; the partition structure and the grouting pipe can retract after the pressure is released after all the grouting is completed, or they can be left in the cave for secondary grouting treatment of the cave; the drilling holes and partition structures are not limited to vertical drilling, but can also be used in horizontal drilling and inclined drilling; the number of partition structures on a single grouting pipe is not limited to one. When multiple partition structures are required, they can be installed on the grouting pipe according to the depth position to be set, and limiting structures can be installed above and below the partition structure.

[0050] The above is only an explanation of the preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0051] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A beaded cave separation grouting structure, comprising a grouting pipe for extending into each cave, characterized in that: The grouting pipe is provided with a partition structure for isolating the communicating gap between the adjacent upper and lower caves, and the partition structure is a shrinkable and deformable bag structure.

2. The beaded cave partition grouting structure according to claim 1, characterized in that: The grouting pipe is provided with limiting structures for protecting the bladder bag above and below the bladder bag structure.

3. The beaded cave partition grouting structure according to claim 1, characterized in that: The bag structure is connected with a water injection pipe.

4. The beaded cave partition grouting structure according to claim 1, characterized in that: The bag structure comprises a bag body and a metal protective shell arranged outside the bag body. The bag body is fixed on the grouting pipe, and the metal protective shell is a group of blade structures that can be opened along with the bag.

5. The beaded cave partition grouting structure according to claim 1, characterized in that: A group of partition structures are arranged at intervals on the grouting pipe.

6. The beaded cave partition grouting structure according to claim 2, characterized in that: The limiting structure is a limiting ring, two limiting rings are fixed on the grouting pipe, and the bag structure is located between the two limiting rings.

7. The beaded cave partition grouting structure according to claim 3, characterized in that: The water injection pipe is provided with a pressure gauge and a control valve.

8. The beaded cave partition grouting structure according to claim 4, characterized in that: The outer layer of the pouch body is provided with a pouch protective cover, and the metal protective shell is a two-part cover shell arranged opposite to each other up and down, and the two parts of the cover shell are respectively fixed on the upper part and the lower part of the pouch protective cover.

9. The beaded cave partition grouting structure according to claim 8, characterized in that: Each of the cover shells is a group of arc-shaped blades arranged in an annular direction.

10. A construction method using the beaded cave partition grouting structure as claimed in any one of claims 1 to 9, characterized in that: The construction method comprises the following steps: 1) After the beaded cave is drilled, the lower grouting pipe and the partition structure on it are lowered to the top plate of the lower cave, and the lowering is stopped. Water is injected into the bag through the water injection pipe to increase pressure, and the bag protective cover and metal protective shell are stretched open to make them contact with the wall of the drilled hole; 2) Then grouting is performed and the grouting pipe is gradually lifted up to grout the lower cave; 3) After the lower cave is filled with grouting and compacted, the valve of the water injection pipe is opened to release the pressure, so that the bag loses water, and the bag protective cover and the metal protective shell are out of contact with the borehole wall; 4) The grouting pipe is synchronously lifted up so that the lower limiting structure of the grouting pipe contacts the metal protective sleeve, and then the whole bag structure and the water injection pipe are lifted up along with the grouting pipe until the partition structure is lifted to the upper cave roof and then stops; 5) Repeatedly inject water into the bag to increase pressure, inject grout into the cave through the grouting pipe, then release the pressure and lift it up to the upper cave until the grouting treatment of all caves is completed.

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