A method for improving the support capacity by using grouting combined with support bolts

Abstract

The present invention discloses a method for improving the support capacity by using grouting combined with support bolts. The first bolt and the second bolt are inserted into concrete to form a reticulated bolt assembly to support the top of the roadway, and the concrete block is supported by the first bolt, the cross bar and the support rod. The present invention combines concrete and bolts for support, with a simple method and easy construction. During the support process, the safety is improved while the corrosion resistance is enhanced, thereby reducing the cost. By arranging grouting grooves on the side surface of the concrete block, grouting can be carried out between the grouting grooves, and a steel plate is fixed outside the grouting grooves. After grouting in the grouting grooves, the adjacent two concrete blocks can be connected to improve the bearing capacity, and the presence of the steel plate also further improves the shear resistance and bearing capacity of the overall support.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel support, and more specifically to a method for improving support capacity by utilizing grouting combined with support anchors. Background Art

[0002] At present, the anchor supports commonly used in underground mining of metal mines are mainly cement mortar anchors, resin anchors, pipe seam anchors, etc., and most of them are made of metal materials. The support forms are basically divided into anchor support, anchor mesh support, anchor spraying support, and spray anchor mesh support. At the support site, it is necessary to select a reasonable support form according to the geological conditions of the mine. However, with the increase in mining depth, the deterioration of mining geological conditions, and the complex and changeable physical and chemical properties of rock formations, these metal anchors and support forms commonly used in metal mines have also encountered the following problems during the support process: (1) low anchoring force; (2) easily affected by the geological environment and corroded and failed; (3) it is not easy to remove the metal anchors during secondary repair and maintenance after the deformation and damage of the tunnel.

[0003] Chinese patent CN101892851B discloses a metal mine anchor support method, which uses glass fiber reinforced plastic anchors to effectively solve the problems existing in metal mines using metal anchor support. However, this technology has obvious shortcomings when used in soft and broken rock areas, mainly because it is difficult to quickly fix the metal mesh and quickly reach the anchoring strength using glass fiber reinforced plastic anchor support alone, thus failing to meet the initial construction safety requirements, and bringing safety hazards to the anchor mesh construction work in the initial support period.

[0004] In summary, when metal mines are supported by simple metal anchors and their corresponding support methods, there are problems such as low anchoring force, susceptibility to corrosion and failure, high support costs, and difficulty in removing during secondary support; and the use of fiberglass anchors for support also has the disadvantages of difficulty in initial hanging of the net, low initial anchoring force and poor safety. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to provide a method for improving the support capacity by using grouting combined with support anchor rods. The method uses a combination of concrete and anchor rods for support. The method is simple and easy to construct. During the support process, it improves shear resistance, bearing capacity, and safety while reducing corrosion resistance, thereby reducing costs.

[0006] A method for improving support capacity by using grouting combined with support anchors, comprising the following steps:

[0007] ① Make plate-shaped grouting template;

[0008] ② Grouting is performed inside the grouting template, and the first anchor rod is inserted in the direction perpendicular to the grouting template;

[0009] ③Before the concrete solidifies, insert the second bolt at the position parallel to the grouting formwork, and both ends of the second bolt extend out of the grouting formwork;

[0010] ④The concrete solidifies to obtain a concrete block with a net-like interior and a grouting groove parallel to the second bolt provided at the end of the concrete block;

[0011] ⑤Drill holes at the top of the roadway, insert the first bolt in step ② into the holes, and grout to fill the gaps between the holes drilled at the top of the roadway and the first bolt, that is, fix the concrete block at the top of the roadway through the first bolt;

[0012] ⑥Splice two concrete blocks along the extension direction of the roadway, the sides with grouting grooves are in contact, and fix steel plates at the upper and lower ends of the splicing position of the two concrete blocks. The steel plate located above is provided with grouting plate holes, and the sides of the grouting grooves are blocked with wooden boards;

[0013] ⑦Insert cross bars at both ends of the second bolt, sleeves of support rods are arranged at both ends of the cross bars, and the support rods are connected to the bottom plate;

[0014] ⑧Grout along the grouting plate holes until the two grouting grooves are filled with grout; wait for the grout to solidify and then remove the wooden boards.

[0015] Further, in step ①, when the grouting formwork is made, its shape matches the shape of the top of the roadway. The top of the roadway is usually arc-shaped or flat-shaped, so the grouting formwork is generally of arc-shaped mold type or rectangular mold type.

[0016] Adopting the above solution: it can adapt to various shapes of the top of the roadway, greatly increasing the contact area between the concrete block and the top of the roadway after being made, and greatly improving the bearing capacity.

[0017] Further, the first bolts are arranged at equal intervals, and the second bolts are arranged at equal intervals.

[0018] Adopting the above solution: insert the first bolts into the concrete block to form a composite structure, improving the support performance of the single-sided concrete block or the single-sided first bolt; the second bolts and the first bolts form a net-like support structure, and under the combination of the concrete blocks, the planar bearing capacity is significantly improved, further enhancing the support ability.

[0019] Further, the grouting groove is a trapezoidal groove, the trapezoidal groove has a long side and a short side, and the long side faces the outside of the concrete block.

[0020] Adopting the above solution: when the trapezoidal groove on the concrete block is under pressure from above, the trapezoidal groove on the concrete block forms an angular support, further improving the bearing capacity of the concrete block and at the same time increasing the shear strength against the shear force from above.

[0021] Further, in step ⑤, the first bolt is a hollow grouting bolt with a plurality of grouting holes on its peripheral surface. The lower opening of the hole drilled at the top of the roadway is tamped with soil blocks. During grouting, grouting is carried out along the lowermost grouting hole of the first bolt. After grouting is completed, the grouting holes are sealed with the grout to complete the fixation of the concrete block.

[0022] Adopting the above solution: By providing grouting holes on the first bolt, it is convenient to fix the first bolt to the rock formation at the top of the roadway, reducing the construction difficulty and facilitating grouting.

[0023] Further, a support steel frame is fixed between the steel plates. The support steel frame and the two steel plates form an I-shaped structure. Through holes are provided on the support steel frame or on both sides of the support steel frame, enabling the grout for grouting to freely fill the grouting groove.

[0024] Further, the end of the cross bar extending out of the support rod is threadedly connected with a fastener. The fastener is detachable and can be installed on the cross bar, such as by threaded connection.

[0025] Adopting the above solution: After the cross bar is set up, the support rod is sleeved on the cross bar. It is convenient for installation and disassembly between the cross bar and the support rod, improving the construction efficiency and reducing the labor intensity.

[0026] Further, a support seat is embedded in the bottom plate, and the lower end of the support rod is connected to the support seat.

[0027] Adopting the above solution: By using the embedded support seat, the bottom of the support rod is firmly enhanced, ensuring the overall supporting foundation capacity.

[0028] Further, the support seat is a cross-shaped fixed pipe, and the cross-shaped fixed pipe is embedded 30 - 50 cm below the bottom plate.

[0029] Adopting the above solution: The cross-shaped fixed pipe has a simple structure, low cost, appropriate embedding depth, is easy to construct, and has a sufficient depth to firmly support the support seat.

[0030] Further, the method for improving the support capacity by using grouting combined with support bolts further includes step ⑨, in which two cross bars arranged along the extension direction of the roadway are welded together.

[0031] Adopting the above solution: The cross bar can be gradually welded and extended as the roadway extends, facilitating the transportation and installation of the cross bar.

[0032] The technical solution of the present invention has achieved the following beneficial technical effects:

[0033] The present invention uses a combination of concrete and bolts for support. The method is simple and easy to construct. During the support process, it improves safety while enhancing the corrosion resistance, thereby reducing costs;

[0034] By arranging grouting grooves on the side surfaces of concrete blocks, grouting can be carried out between the grouting grooves, and steel plates are fixed outside the grouting grooves. After grouting in the grouting grooves, two adjacent concrete blocks can be connected to improve the bearing capacity. At the same time, the presence of the steel plates also further enhances the shear resistance and bearing capacity of the overall support. Description of the Drawings

[0035] Figure 1 It is a schematic flow chart of the steps of an embodiment of the present invention;

[0036] Figure 2 It is a schematic structural diagram of the combined support structure of an embodiment of the present invention;

[0037] Figure 3 It is a schematic bottom view structural diagram of the combined support structure of an embodiment of the present invention;

[0038] Figure 4 It is a schematic cross-sectional diagram of a concrete block of an embodiment of the present invention;

[0039] Figure 5 It is a connection schematic diagram of a cross bar of an embodiment of the present invention.

[0040] The reference numerals in the drawings are represented as: 1 - concrete block, 2 - steel plate, 21 - support steel frame, 3 - grouting groove, 4 - first anchor bolt, 5 - second anchor bolt, 6 - cross bar, 61 - welding ring, 7 - support rod, 8 - fastener. Detailed Embodiment

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0042] As Figures 1 to 5 shown, a method for improving the support capacity by using grouting combined support anchor bolts includes the following steps:

[0043] ① Fabricate a plate-shaped grouting template; when fabricating the grouting template, measure the shape of the top of the roadway at the position to be installed in the roadway, and fabricate the grouting template according to the shape of the top of the roadway. The top of the roadway is usually arc-shaped or flat-shaped, so the grouting template is generally of the arc-shaped mold type or the rectangular mold type; the grouting template matching the shape of the top of the roadway greatly increases the contact area between the fabricated concrete block 1 and the top of the roadway, and greatly improves the bearing capacity;

[0044] ② Grout inside the grouting template, and insert a number of first anchor bolts 4 in the direction perpendicular to the grouting template, and the first anchor bolts 4 are arranged at equal distances;

[0045] ③Before the concrete solidifies, insert several second anchor rods 5 at the position parallel to the grouting formwork. The second anchor rods 5 are equidistantly arranged, and both ends of the second anchor rods 5 extend out of the grouting formwork, reserving for the fixation of both ends of the second anchor rods 5 in the subsequent steps. The first anchor rods 4 and the second anchor rods 5 are also arranged at intervals in the concrete block 1. The second anchor rods 5 and the first anchor rods 4 form a reticulated support structure. Under the combination of the concrete block 1, the planar bearing capacity is significantly improved, further enhancing the support capacity.

[0046] ④The concrete solidifies to obtain a concrete block 1 with a reticulated interior and a grouting groove 3 parallel to the second anchor rod 5 provided at the end of the concrete block 1. Preferably, the grouting groove 3 is formed by restricting the pouring of concrete by the shape of the grouting formwork itself.

[0047] ⑤Drill holes at the top of the roadway, insert the first anchor rods 4 in the holes, and grout to fill the gaps between the holes drilled at the top of the roadway and the first anchor rods 4, that is, fix the concrete block 1 at the top of the roadway through the first anchor rods 4. After the first anchor rods 4 are installed, the first anchor rods 4 only contact the grouting slurry solidified in the concrete block 1 and the holes drilled at the top of the roadway, avoiding the direct contact between the first anchor rods 4 and the surrounding rock, thereby reducing the risk of corrosion. The anti-corrosion effect can be achieved without using fiberglass anchor rods.

[0048] ⑥Splice two concrete blocks 1 along the extension direction of the roadway, the sides provided with the grouting grooves 3 are in contact, and steel plates 2 are fixed by bolts at the upper and lower ends of the splicing position of the two concrete blocks 1. A support steel frame 21 is welded between the steel plates 2. The support steel frame 21 and the two steel plates 2 form an I-shaped structure. Through holes are provided on the support steel frame 21 or on both sides of the support steel frame 21, so that the grouting slurry can freely fill the grouting groove 3. When grouting, the sides of the grouting groove 3 need to be blocked with wooden boards.

[0049] ⑦Insert cross bars 6 at both ends of the second anchor rods 5, sleeves 7 are sleeved at both ends of the cross bars 6, and the sleeves 7 are connected to the ground.

[0050] ⑧Grout into the grouting groove 3 along the grouting plate holes until the two grouting grooves 3 are filled with slurry; wait for the slurry to solidify and then remove the wooden boards.

[0051] Further, as Figure 4 shown, the grouting groove 3 is a trapezoidal groove. The trapezoidal groove has a long side and a short side. The long side faces outside the concrete block 1, and the short side is inside the concrete block 1. When pressure is applied above the concrete block 1, due to the angular support formed by the trapezoidal groove on the concrete block 1, the bearing capacity of the concrete block 1 is further improved, and at the same time, the shear strength against the shear force from above is increased.

[0052] Further, in step ⑤, the first anchor rod 4 is a hollow grouting anchor rod and a plurality of grouting holes are opened on the circumference. The lower end opening of the hole drilled on the top of the tunnel is compacted with a soil block. During grouting, grouting is performed along the grouting hole at the bottom of the first anchor rod 4. After the grouting is completed, the grouting hole is sealed with slurry to complete the fixation of the concrete block 1. When installing this concrete block 1, the first anchor rod 4 is first inserted into the top of the tunnel. During the insertion, a hole is opened at the top of the tunnel. The hole depth is consistent with the exposed length of the anchor rod, and the hole diameter is slightly larger than the anchor rod diameter. After the first anchor rod 4 is placed, a soil block is pressed into the bottom of the hole at the top of the tunnel to compact it to prevent the slurry from dripping along the hole in an unsolidified state during grouting. After compaction, grouting is performed along the grouting hole at the bottom of the first anchor rod 4. After the grouting is completed, the grouting hole is sealed with slurry to complete the fixation of the concrete block 1.

[0053] Since it is necessary to grout from the grouting hole at the lower end of the first anchor rod 4 in step ⑤, a section of the first anchor rod 4 is located between the bottom of the tunnel top and the concrete block 1. When grouting into the grouting groove 3 in step ⑧, the gap between the top of the concrete block 1 and the tunnel top wall can be utilized to extend the grouting pipe into the gap and grout into the grouting plate hole; the gap between the top of the concrete block 1 and the tunnel top plate can also be filled with grouting at the end, so that the concrete block 1 is tightly connected to the tunnel top plate.

[0054] Further, such as Figure 2 , Figure 3 , Figure 5 As shown, in step ⑦, the end of the cross bar 6 extending out of the support rod 7 is threadedly connected with a fastener 8, and the fastener 8 is detachably installed on the cross bar 6, such as threading a fastening nut or a U-shaped tube fastener at the end of the cross bar 6 extending out of the support rod 7, which facilitates the installation and disassembly between the cross bar 6 and the support rod 7, improves construction efficiency, and reduces labor intensity;

[0055] A support seat is embedded in the base plate, and the lower end of the support rod 7 is connected to the support seat; specifically, the support seat is a cross fixing tube, and the cross fixing tube is embedded 30 to 50 cm below the ground; first, a support rod 7 of a suitable height is selected according to the height of the cross bar 6, and the bottom of the support rod 7 is connected to the cross fixing tube by welding, and the cross fixing tube is embedded in the ground, and the upper end of the support rod 7 is fixed to the cross bar 6 with screws; in this embodiment, the embedded support seat is used to stabilize and strengthen the bottom of the support rod 7 to ensure the overall support foundation capacity.

[0056] The working principle of the present invention is as follows: The first anchor rod 4 and the second anchor rod 5 are inserted into the concrete block 1 to form a reticulated anchor rod assembly. The concrete block 1 serves as a bearing block and is fabricated first to increase the bearing capacity. Then, two grouting grooves 3 are used to connect two adjacent concrete blocks 1 to complete the support of the entire roadway roof. At the same time, fixing steel plates 2 are arranged on both the upper and lower sides of the grouting groove 3 between the two concrete blocks 1. A support steel frame 21 is welded between the two steel plates 2 and filled with cement slurry to further solve the bearing capacity at the connection and improve the overall shear resistance and bearing performance. The concrete blocks 1 are cast sequentially along the extension direction of the roadway. The cross bar 6 used to support the second anchor rod 5 can be gradually welded and extended as the roadway extends. The cross bar 6 is welded section by section to form one or more long rods. Figure 5 The welded ring 61 formed after welding two cross bars 6 is schematically shown in Figure 5 ; finally, the cross bar 6 is supported by the support rod 7 to support the concrete block 1 from the ground to complete the fabrication of the entire support structure.

[0057] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom still fall within the protection scope of the claims of this patent application.

Claims

1. A method for enhancing the support capacity by using grouting combined with support bolts, characterized in that The steps include: ① Make plate-shaped grouting template; ② Grouting inside the grouting template and inserting the first anchor rod (4) in a direction perpendicular to the grouting template; ③ Before the concrete solidifies, a second anchor rod (5) is inserted into the parallel grouting template, and both ends of the second anchor rod (5) extend out of the grouting template; ④ The concrete solidifies, and a concrete block (1) is obtained, which has a mesh-shaped interior and a grouting groove (3) parallel to the second anchor rod (5) is provided at the end of the concrete block (1); ⑤ drilling a hole at the top of the tunnel, inserting the first anchor rod (4) in step ② into the hole, and performing grouting to fill the gap between the hole drilled at the top of the tunnel and the first anchor rod (4); ⑥ Splicing two concrete blocks (1) along the extension direction of the tunnel, with the sides of the grouting groove (3) being abutted against each other, and fixing steel plates (2) at the upper and lower ends of the splicing positions of the two concrete blocks (1), with the grouting plate holes being provided on the upper steel plate (2), and the sides of the grouting groove (3) being blocked with wooden boards; ⑦ The cross bars (6) are inserted into the two ends of the second anchor bar (5), and the two ends of the cross bar (6) are sleeved with support bars (7), and the support bars (7) are connected to the bottom plate; ⑧ Grouting along the holes of the grouting plate until the two grouting grooves (3) are filled with grout; When the slurry solidifies, remove the wooden board; ⑨ Two cross bars (6) arranged along the extension direction of the lane are welded and connected.

2. The method for improving the support capacity by using grouting combined with support bolts according to claim 1, characterized in that In step ①, the shape of the grouting template matches the shape of the tunnel top during production.

3. The method for improving the support capacity by using grouting combined with support bolts according to claim 1, characterized in that, The first anchor rods (4) are arranged at equal distances from each other, and the second anchor rods (5) are arranged at equal distances from each other.

4. The method for improving the support capacity by using grouting combined with support bolts according to claim 1, characterized in that, The grouting groove (3) is a trapezoidal groove having a long side and a short side, wherein the long side faces the outside of the concrete block (1).

5. The method for improving the support capacity by using grouting combined with support bolts according to claim 1, characterized in that, In step ⑤, the first anchor rod (4) is a hollow grouting anchor rod and has a plurality of grouting holes on its circumference. The lower opening of the hole drilled at the top of the tunnel is compacted with soil blocks, and grouting is performed along the grouting hole at the bottom of the first anchor rod (4).

6. The method for improving the support capacity by using grouting combined with support bolts according to claim 1, characterized in that, A supporting steel frame (21) is fixed between the steel plates (2), and the supporting steel frame (21) and the two steel plates (2) form an I-shaped structure.

7. The method for improving the support capacity by using grouting combined support bolts according to claim 1, characterized in that, The end of the cross bar (6) extending out of the support bar (7) is threadedly connected with a fastener (8).

8. The method for improving the support capacity by using grouting combined support bolts according to claim 1, characterized in that, A support seat is pre-buried in the base plate, and the lower end of the support rod (7) is connected to the support seat.

9. The method for improving the support capacity by using grouting combined support bolts according to claim 8, characterized in that, The support base is pre-buried 30 to 50 cm below the ground.

Images