A soft rock roadway drilling construction method

Abstract

The present application relates to the technical field of coal mine engineering, and particularly relates to a soft rock roadway drilling construction method. The method comprises the following steps: step one, connecting a roof; step two, installing a drill rod on an anchor rod machine, the drill rod comprising a twist drill rod and a hexagonal drill rod connected at the head and tail, and installing a drill bit at the free end of the hexagonal drill rod; step three, drilling by operating the anchor rod machine; step four, when the drilling depth reaches the length of the drill rod, withdrawing the drill rod; step five, connecting a hexagonal drill rod and / or a twist drill rod at the end of the drill rod away from the drill bit to extend the length of the drill rod, and then continuing drilling, when the drilling depth reaches the length of the drill rod, withdrawing the drill rod; and step six, repeating step five until the drilling depth reaches the designed drilling depth. The present application uses the combination of a twist drill rod and a hexagonal drill rod to perform soft rock roadway drilling construction, and the hexagonal drill rod is connected with the drill bit, thereby avoiding the reduction of drilling efficiency caused by rock powder and mud, reducing the wear of the twist drill rod, and improving the connection strength between the drill rods.

Description

Technical Field

[0001] This invention relates to the field of coal mine engineering technology, specifically to a drilling construction method for soft rock roadways. Background Technology

[0002] Soft rock is a type of rock mass between rock and soil, characterized by low strength and high plasticity, making it prone to collapse and deformation. Due to the poor stability and low strength of soft rock strata, anchor bolts or cables are required to support the roof of soft rock tunnels during construction. Both anchor bolt and cable support require pre-drilling holes in the surface or surrounding rock mass and applying prestress within the holes to enhance the tensile strength of the soil or rock mass, thereby achieving the purpose of support.

[0003] In soft rock tunnel excavation, roof anchor bolts or cable anchors are crucial for construction safety. Installing anchor bolts or cable anchors requires drilling holes in the roof for anchoring. Hexagonal drill rods and twist drill rods are commonly used drill rods in drilling operations. Hexagonal drill rods offer advantages such as high drill bit precision, strong wear resistance, fast drilling efficiency, and high tensile strength. However, when the roof rock mass is sandy mudstone, the hardness coefficient f < 1.5, making it prone to mudification upon contact with water. During drilling operations on this type of roof rock mass, the rock dust produced by the mudification will adhere to the hexagonal drill rod, reducing drilling efficiency or even preventing further drilling. While twist drill rods can effectively remove rock dust generated during drilling, they have low drilling efficiency and precision, and poor wear resistance. Therefore, special care and maintenance are required to extend their service life to some extent.

[0004] To improve drilling efficiency in soft rock tunnel roof rock masses, patent application number 202110101261.2 discloses a side-anchoring drill rod that utilizes welded spiral ribs on the outside of a hollow rod body to remove drill cuttings. Although this method can remove drill cuttings during drilling, the drill rods are all made of hollow rod bodies with welded spiral ribs connected by a connecting mechanism. On the one hand, the hollow rods with welded spiral ribs are prone to wear, and the manufacturing process of the hollow rod bodies with welded spiral ribs is complex. On the other hand, the connecting mechanism consists of two semi-circular plates fixed by four conical screws, and the strength of the connecting mechanism is greatly affected by the disassembly and assembly process. Summary of the Invention

[0005] To address the technical problems of easy wear of drill rods, unstable strength of connection mechanisms, and complex disassembly and assembly procedures in existing technologies for drilling soft rock roadways, this invention provides a drilling method for soft rock roadways. A connecting sleeve is used to connect the twist drill rod to the tail of the hexagonal drill rod connected to the drill bit. This method avoids reduced drilling efficiency due to rock powder turning into mud during drilling, while also reducing wear on the twist drill rod and improving the connection strength between drill rods.

[0006] This invention provides a method for drilling in soft rock tunnels, comprising the following steps: Step 1: After the soft rock roadway is cut at the face, deploy the temporary support frame, place the materials needed for drilling on the temporary support frame, raise the temporary support frame, and connect it to the roof. Step 2: Install the drill rod onto the anchor bolting machine. The drill rod consists of a twist drill rod and a hexagonal drill rod connected end to end. Install the drill bit on the free end of the hexagonal drill rod. Step 3: Raise the air leg of the anchor bolting machine and simultaneously align the drill bit with the preset drilling position. Once the drill bit contacts the top plate, operate the anchor bolting machine to drill the hole. Step 4: When the drilling depth reaches the length of the drill rod, retract the drill rod; Step 5: Connect a hexagonal drill rod and / or a twist drill rod to the end of the drill rod away from the drill bit to extend the length of the drill rod. Then continue drilling. When the drilling depth reaches the length of the drill rod, retract the drill rod. Step 6: Repeat step 5 until the drilling depth reaches the designed drilling depth.

[0007] Furthermore, in step one, the materials required for drilling include steel strips and metal mesh; the top plate is sandy mudstone with a hardness coefficient f < 1.5. Sandy mudstone has low hardness and is mainly composed of clay, mud particles, and quartz. The bonding force between the particles is weak, and it easily turns into mud when exposed to water, thus adhering to the area around the drill pipe.

[0008] Furthermore, the hexagonal drill rod is a B19 hexagonal drill rod, and the twist drill rod has a hollow structure with threads at both ends, an outer diameter of 28mm, and a length of 500-1000mm.

[0009] Furthermore, in step two, the anchor bolting machine is an MQT-130 / 2.8T pneumatic anchor bolting drill with a drill bit diameter of 32mm.

[0010] Furthermore, in step three, drilling begins when the speed of the anchor bolting machine reaches 270-380 r / min.

[0011] Furthermore, in steps four and five, the drill rod retracts under its own weight along with the anchor bolting machine.

[0012] Furthermore, the hexagonal drill rod is connected to the twist drill rod, the hexagonal drill rod is connected to the hexagonal drill rod, and the twist drill rod is connected to the twist drill rod via connecting sleeves.

[0013] Furthermore, the connecting sleeve is made of high-strength steel, with a length of 50mm and internal threads. The connecting sleeve can be used to connect drill rods of the same or different types. The inner diameters at both ends of the connecting sleeve can be the same or different, and the inner diameters at both ends are adapted to the corresponding drill rods. The inner diameter of the end of the connecting sleeve connected to the hexagonal drill rod is 19mm. Using a connecting sleeve made of high-strength steel to connect hexagonal drill rods and / or twist drill rods helps improve the strength of the drill rod connection. The internal threaded connection of the connecting sleeve has the advantages of simple structure, high stability, and convenient assembly and disassembly, and also prevents rock powder discharged from the borehole from entering the threaded gaps.

[0014] The beneficial effects of this invention are as follows: This invention provides a drilling method for soft rock tunnels. A connecting sleeve is used to connect twist drill rods and hexagonal drill rods end-to-end, forming a drill rod. The drill rod is easy to manufacture and disassemble, flexible to use, and has high connection stability. Installing the drill bit at the free end of the hexagonal drill rod reduces wear on the twist drill rod from the tunnel roof rock mass, extending its service life. Furthermore, it minimizes the impact of introducing the twist drill rod on the overall drilling device, enabling drilling to achieve both dust removal and improved drilling accuracy using a drill bit compatible with the hexagonal drill rod.

[0015] This invention utilizes existing anchor bolting machines, drill bits, and drill rods for drilling in soft rock tunnels. It employs a method of gradually increasing the number of hexagonal drill rods and / or twist drill rods on the drill rod to drill into soft rock roofs at different design depths. During the drilling process, the position of the hexagonal or twist drill rods can be flexibly adjusted according to the construction conditions and rock powder discharge, simplifying the drilling process in soft rock tunnels, reducing the construction cost, and demonstrating strong adaptability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the drill rod used in step two of Embodiment 1 of the present invention.

[0018] In the diagram, 1-twist drill rod, 2-connecting sleeve, 3-hexagonal drill rod. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0020] The soft rock roof in this embodiment is the roof of coal seam 11 in Luxin Coal Mine. The roof lithology is generally sandy mudstone and siltstone, with conglomerate near the erosion surface, and an average thickness of 15.32m. The floor lithology is sandy mudstone or siltstone, with an average thickness of 5.63m. The roof and floor are prone to mudification when exposed to water, and the hardness coefficient f < 1.5.

[0021] The anchor bolting machine is an MQT-130 / 2.8T pneumatic anchor bolting drill, and the φ32mm drill bit is a coal mine diamond composite anchor bolting drill bit ZTFB32 / 2-A grade produced by Zhoukou Yaxin Mining Machinery Co., Ltd.

[0022] The holes drilled in Examples 1-4 are used to anchor anchor bolts and / or anchor cables.

[0023] Example 1 The drill rod in this embodiment includes a 1000mm long B19 hexagonal drill rod and a 1000mm long twist drill rod with an outer diameter of 28mm. The twist drill rod has threads at both ends formed by wire pulling. The connecting sleeve used in this embodiment is a B19 connecting sleeve, purchased from Zhongtai Gas Tools (Shandong) Co., Ltd. The hexagonal drill rod, twist drill rod, and connecting sleeve are all connected by threads.

[0024] A method for drilling in soft rock tunnels includes the following steps: Step 1: After the face of the 11105 transport roadway at Luxin Coal Mine is cut, a temporary support frame is deployed. After placing steel strips and metal mesh on the temporary support frame, the roadheader operator raises the onboard hydraulic temporary support frame to connect with the soft rock roof, providing a safe space for drilling operations.

[0025] Step 2: Install the drill rod onto the anchor bolting machine. The drill rod consists of a twist drill rod and a hexagonal drill rod connected end to end. Install the φ32mm drill bit on the free end of the hexagonal drill rod. Connect the anchor bolting machine to the air inlet and water inlet connectors.

[0026] Step 3: Raise the air leg of the anchor bolting machine and simultaneously align the drill bit with the preset drilling position. After the drill bit contacts the soft rock roof, operate the anchor bolting machine to increase the speed. When the speed reaches 270 r / min, start drilling.

[0027] Step 4: When the drilling depth reaches 2000mm, retract the drill rod as follows: turn off the air intake of the anchor bolt machine's air leg, reduce the water output, and slow down the rotation speed so that the anchor bolt machine can smoothly lower the drill rod by its own weight.

[0028] Step 5: After the drill rod returns to its original position, use a connecting sleeve to connect a 1000mm long hexagonal drill rod to the end of the drill rod away from the drill bit to extend the length of the drill rod. Reinstall the drill rod onto the anchor bolting machine to continue drilling. When the drilling depth reaches 3000mm, retract the drill rod.

[0029] Step 6: Repeat step 5 until the drilling depth reaches the designed drilling depth of 6.3m.

[0030] Example 2 The drill rod in this embodiment includes a 1000mm long B19 hexagonal drill rod and a 500mm long twist drill rod with an outer diameter of 28mm. The twist drill rod has threads at both ends formed by wire pulling. The connecting sleeve used in this embodiment is a B19 connecting sleeve, purchased from Zhongtai Gas Tools (Shandong) Co., Ltd. The hexagonal drill rod, twist drill rod, and connecting sleeve are all connected by threads.

[0031] A method for drilling in soft rock tunnels includes the following steps: Step 1: After the face of the 11105 transport roadway at Luxin Coal Mine is cut, a temporary support frame is deployed. After placing steel strips and metal mesh on the temporary support frame, the roadheader operator raises the onboard hydraulic temporary support frame to connect with the soft rock roof, providing a safe space for drilling operations.

[0032] Step 2: Install the drill rod onto the anchor bolting machine. The drill rod consists of a twist drill rod and a hexagonal drill rod connected end to end. Install the φ32mm drill bit on the free end of the hexagonal drill rod. Connect the anchor bolting machine to the air inlet and water inlet connectors.

[0033] Step 3: Raise the air leg of the anchor bolting machine and simultaneously align the drill bit with the preset drilling position. After the drill bit contacts the soft rock roof, operate the anchor bolting machine to increase the speed. When the speed reaches 380 r / min, start drilling.

[0034] Step 4: When the drilling depth reaches 1500mm, retract the drill rod as follows: turn off the air intake of the anchor bolt machine's air leg, reduce the water output, and slow down the rotation speed so that the anchor bolt machine can smoothly lower the drill rod by its own weight.

[0035] Step 5: After the drill rod returns to its original position, use a connecting sleeve to connect a 1000mm long hexagonal drill rod to the end of the drill rod away from the drill bit, extending the length of the drill rod. Reinstall the drill rod onto the anchor bolting machine to continue drilling. When the drilling depth reaches 2500mm, retract the drill rod.

[0036] Step 6: Repeat step 5 until the drilling depth reaches the designed drilling depth of 6.5m.

[0037] Example 3 The drill rod in this embodiment includes a 1000mm long B19 hexagonal drill rod and an 800mm long twist drill rod with an outer diameter of 28mm. The twist drill rod has threads at both ends formed by wire pulling. The connecting sleeve used in this embodiment is a B19 connecting sleeve, purchased from Zhongtai Gas Tools (Shandong) Co., Ltd. The hexagonal drill rod, twist drill rod, and connecting sleeve are all connected by threads.

[0038] A method for drilling in soft rock tunnels includes the following steps: Step 1: After the face of the 11105 transport roadway at Luxin Coal Mine is cut, a temporary support frame is deployed. After placing steel strips and metal mesh on the temporary support frame, the roadheader operator raises the onboard hydraulic temporary support frame to connect with the soft rock roof, providing a safe space for drilling operations.

[0039] Step 2: Install the drill rod onto the anchor bolting machine. The drill rod consists of a twist drill rod and a hexagonal drill rod connected end to end. Install the φ32mm drill bit on the free end of the hexagonal drill rod. Connect the anchor bolting machine to the air inlet and water inlet connectors.

[0040] Step 3: Raise the air leg of the anchor bolting machine and simultaneously align the drill bit with the preset drilling position. After the drill bit contacts the soft rock roof, operate the anchor bolting machine to increase the speed. When the speed reaches 350 r / min, start drilling.

[0041] Step 4: When the drilling depth reaches 1800mm, retract the drill rod as follows: turn off the air intake of the anchor bolt machine's air leg, reduce the water output, and slow down the rotation speed so that the anchor bolt machine can smoothly lower the drill rod by its own weight.

[0042] Step 5: After the drill rod returns to its original position, use a connecting sleeve to connect an 800mm long twist drill rod to the end of the drill rod away from the drill bit to extend the length of the drill rod. Reinstall the drill rod onto the anchor bolting machine to continue drilling. When the drilling depth reaches 2600mm, retract the drill rod.

[0043] Step Six: After the drill rod returns to its original position, use a connecting sleeve to connect a 1000mm long hexagonal drill rod to the end of the drill rod furthest from the drill bit, extending the length of the drill rod. Reinstall the drill rod onto the anchor bolting machine to continue drilling. When the drilling depth reaches 3600mm, retract the drill rod.

[0044] Step 7: Repeat step 6 until the drilling depth reaches the designed drilling depth of 7.6m.

[0045] Example 4 The drill rod in this embodiment includes a 1000mm long B19 hexagonal drill rod and a 1000mm long twist drill rod with an outer diameter of 28mm. The twist drill rod has threads at both ends formed by wire pulling. The connecting sleeve used in this embodiment is a B19 connecting sleeve, purchased from Zhongtai Gas Tools (Shandong) Co., Ltd. The hexagonal drill rod, twist drill rod, and connecting sleeve are all connected by threads.

[0046] A method for drilling in soft rock tunnels includes the following steps: Step 1: After the face of the 11105 transport roadway at Luxin Coal Mine is cut, a temporary support frame is deployed. After placing steel strips and metal mesh on the temporary support frame, the roadheader operator raises the onboard hydraulic temporary support frame to connect with the soft rock roof, providing a safe space for drilling operations.

[0047] Step 2: Install the drill rod onto the anchor bolting machine. The drill rod consists of a twist drill rod and a hexagonal drill rod connected end to end. Install the φ32mm drill bit on the free end of the hexagonal drill rod. Connect the anchor bolting machine to the air inlet and water inlet connectors.

[0048] Step 3: Raise the air leg of the anchor bolting machine and simultaneously align the drill bit with the preset drilling position. After the drill bit contacts the soft rock roof, operate the anchor bolting machine to increase the speed. When the speed reaches 285 r / min, start drilling.

[0049] Step 4: When the drilling depth reaches 3000mm, retract the drill rod as follows: turn off the air intake of the anchor bolt machine's air leg, reduce the water output, and slow down the rotation speed so that the anchor bolt machine can smoothly lower the drill rod by its own weight.

[0050] Step 5: After the drill rod returns to its original position, use a connecting sleeve to connect a 500mm long twist drill rod to the end of the drill rod away from the drill bit to extend the length of the drill rod. Reinstall the drill rod onto the anchor bolting machine to continue drilling. When the drilling depth reaches 3500mm, retract the drill rod.

[0051] Step Six: After the drill rod returns to its original position, use a connecting sleeve to connect a 1000mm long hexagonal drill rod to the end of the drill rod furthest from the drill bit, extending the length of the drill rod. Reinstall the drill rod onto the anchor bolting machine to continue drilling. When the drilling depth reaches 4500mm, retract the drill rod.

[0052] Step 7: Repeat step 6 until the drilling depth reaches the designed drilling depth of 6.5m.

[0053] Compare with Example 1 The difference between Comparative Example 1 and Example 1 is that only a B19 hexagonal drill rod with a length of 1000mm was used for drilling.

[0054] The drilling methods of Examples 1-4 did not exhibit the phenomenon of "no foaming or sticking to the drill bit" during the entire drilling process. However, the drilling method of Comparative Example 1 exhibited the phenomenon of "no foaming or sticking to the drill bit" when the drill entered the soft rock roof, making it impossible to continue drilling. This indicates that the drilling method for soft rock tunnels disclosed in the embodiments of the present invention can ensure efficient and rapid drilling operations in soft rock tunnels.

[0055] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A method for drilling in soft rock tunnels, characterized in that, Includes the following steps: Step 1: After the soft rock roadway is cut at the face, deploy the temporary support frame, place the materials needed for drilling on the temporary support frame, raise the temporary support frame, and connect it to the roof. Step 2: Install the drill rod onto the anchor bolting machine. The drill rod consists of a twist drill rod and a hexagonal drill rod connected end to end. Install the drill bit on the free end of the hexagonal drill rod. Step 3: Raise the air leg of the anchor bolting machine and simultaneously align the drill bit with the preset drilling position. Once the drill bit contacts the top plate, operate the anchor bolting machine to drill the hole. Step 4: When the drilling depth reaches the length of the drill rod, retract the drill rod; Step 5: Connect a hexagonal drill rod and / or a twist drill rod to the end of the drill rod away from the drill bit to extend the length of the drill rod. Then continue drilling. When the drilling depth reaches the length of the drill rod, retract the drill rod. Step 6: Repeat step 5 until the drilling depth reaches the designed drilling depth.

2. The drilling method for soft rock tunnels as described in claim 1, characterized in that, In step one, the materials required for drilling include steel strips and metal mesh; the top plate is sandy mudstone with a hardness coefficient f < 1.

5.

3. The drilling method for soft rock tunnels as described in claim 1, characterized in that, The hexagonal drill rod is a B19 hexagonal drill rod. The twist drill rod has a hollow structure with threads at both ends, an outer diameter of 28mm, and a length of 500-1000mm.

4. The drilling method for soft rock tunnels as described in claim 1, characterized in that, In step two, the anchor bolting machine is an MQT-130 / 2.8T pneumatic anchor bolting drill with a drill bit diameter of 32mm.

5. The drilling method for soft rock tunnels as described in claim 1, characterized in that, In step three, drilling begins when the bolting machine reaches a speed of 270-380 r / min.

6. The drilling method for soft rock tunnels as described in claim 1, characterized in that, In steps four and five, the drill rod retracts under its own weight along with the anchor bolting machine.

7. The drilling method for soft rock tunnels as described in claim 1, characterized in that, Hexagonal drill rods are connected to twist drill rods, hexagonal drill rods to hexagonal drill rods, and twist drill rods to twist drill rods respectively via connecting sleeves.

8. The drilling method for soft rock tunnels as described in claim 7, characterized in that, The connecting sleeve is made of high-strength steel, with a length of 50mm and internal threads.

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