An inner opening anti-falling equipment for a river bottom shield machine frozen reinforcement machine shell and a construction method thereof

Abstract

This invention discloses a device and construction method for preventing the tunnel boring machine (TBM) shell from falling into the ground during freezing and reinforcement of the shield machine shell. It relates to the field of freezing construction during TBM shutdown for ground reinforcement. The device includes a hollow drill rod with a toothed drill bit at its head. To stabilize the hollow drill rod and facilitate core extraction, a borehole pipe is fitted around the outer circumference of the hollow drill rod, and a sealing sleeve is fitted around the outer circumference of the borehole pipe to ensure tightness during drilling and prevent pressure loss between the TBM and the outside environment. A water injection hole is opened at the tail of the hollow drill rod, and an external cooling water pipe is installed inside the water injection hole to inject cooling water to cool the toothed drill bit. This invention prevents the drilled-out TBM shell from falling into the external strata and jamming the subsequent drilling during the drilling process by adding a locking mechanism inside the borehole pipe. External water and soil pressure pushes the drilled-out TBM shell back into the TBM, achieving the purpose of removing the shell and preventing it from falling into the external strata.

Description

Technical Field

[0001] This invention relates to the field of seasonal freezing construction for shield tunneling machine shutdown and ground reinforcement, and in particular to a device for preventing rockfalls by opening holes inside the casing of a shield tunneling machine for freezing reinforcement under riverbeds, and its construction method. Background Technology

[0002] Currently, highway shield tunnel construction is developing towards larger diameters, deeper burial depths, and ultra-long distances. Especially for long shield tunnels crossing riverbeds or seabeds, the extreme length of these tunnels constantly challenges the performance of the tunnel boring machines (TBMs). There are generally two approaches to constructing ultra-long shield tunnels. One is to improve the service performance of key equipment such as the main drive, bearings, seals, cutterhead, tail brush, pumps, and pipelines. The other is to excavate the foundation pit on an island in the water and use two TBMs to excavate in opposite directions to reduce the excavation distance of a single TBM.

[0003] Both of the aforementioned mainstream approaches have their own problems. Current technology makes it difficult to significantly improve the performance of key tunnel boring machine (TBM) equipment in the short term. Furthermore, when the waterway being tunneled through lacks islands, artificial island construction is necessary, leading to excessive costs and long construction periods. Besides these two methods, another approach involves launching two TBMs from opposite banks, tunneling towards each other, and then connecting underwater. This method carries higher construction risks and requires stable ground conditions or the use of appropriate technologies to stabilize the underwater strata at the TBM docking stage.

[0004] Currently, the most widely used technology for stabilizing strata is cryogenic treatment. This involves creating cryogenic holes inside the tunnel boring machine and inserting cryogenic pipes into the external strata. The brine or liquid nitrogen in the cryogenic pipes circulates continuously, cooling the strata and ultimately hardening and stabilizing them.

[0005] For example, application number CN208763610U discloses an anti-drop-out coring device for geological drilling. This device adds a connecting device between the drill rod and the core tube, ensuring that even if the core tube breaks during drilling, it remains connected to the upper drill rod, preventing it from getting stuck or falling into the borehole and thus avoiding the phenomenon of core dropping, thereby improving the borehole success rate. The main idea is to modify the drill rod to form a groove that embeds into the casing, with the casing and core tube connected by a connecting rod. Even if the core tube is damaged or breaks during drilling, it can still be connected to the drill rod via the connecting rod, allowing the damaged core tube to be safely pulled out of the borehole, thereby improving the borehole success rate in geological drilling. The anti-drop-out coring device primarily focuses on preventing core dropping, i.e., maintaining connection to the drill rod via an external connecting rod even if the core tube breaks. However, it does not include measures to prevent the core sample extracted by the core rod from falling out. Meanwhile, the introduction of the anti-drill-fall coring device only describes the device itself, without simultaneously introducing its construction method.

[0006] For example, application number CN208918499U discloses a tool for retrieving debris from the borehole of a directional drilling project for subsea pipelines. This tool uses a plate-shaped anti-drop auger installed inside the directional drilling rig of the subsea tow pipe, connected to the tow pipe via a connecting thread at the top of the pipe. During subsea directional drilling, the plate-shaped auger rotates to lift debris from the pipe, preventing the drill from getting stuck. The design of this tool primarily considers how to prevent seabed debris from getting stuck on the tow rod by using the rotating lifting mechanism of the plate-shaped auger to clear the borehole. This method is effective in clearing small stones. However, its structure is prone to jamming when encountering certain special structures (such as garbage bags, ropes, or larger rocks), failing to achieve the intended effect. Furthermore, the use of plate-shaped material in the auger structure raises concerns about its durability and rigidity. Finally, this device cannot be used to clean debris with a diameter close to that of the tow rod; the size of the debris it can remove depends on the size of the opening in the auger structure. The gentler the spiral, the larger the debris it can clean, but the longer the spiral needs to lift it. The steeper the spiral, the smaller the debris it can clean, but the less effective it is at lifting debris.

[0007] In general, existing technologies primarily focus on preventing drill bit loss, with less attention paid to protecting or preventing the retrieved core sample from falling out. The current mainstream design approach for preventing drill bit loss involves installing chucks or traction locks on the drill rod, allowing for quick retrieval should the drill bit fall into the borehole, preventing drill bit loss and borehole blockage. However, existing technologies have certain practical problems, such as difficulty in retrieving the drill bit and drill bit jamming. Summary of the Invention

[0008] Therefore, it is necessary to provide a device for preventing block falling through the opening in the casing of a tunnel boring machine under riverbed and its construction method to address the above-mentioned technical problems.

[0009] In a first aspect, the present invention provides a device for preventing block falling during the internal opening of a tunnel boring machine (TBM) under riverbed for cryogenic reinforcement. The device includes a hollow drill rod with a toothed drill bit at its head. To achieve pipe stabilization and core extraction of the hollow drill rod, a borehole pipe is fitted around the outer circumference of the hollow drill rod, and a sealing sleeve is fitted around the outer circumference of the borehole pipe to ensure the tightness of the drilling process and prevent pressure loss between the TBM and the outside world. A water injection hole is opened at the tail of the hollow drill rod, and an external cooling water pipe is installed inside the water injection hole to inject cooling water to cool the toothed drill bit.

[0010] Furthermore, the length of the orifice tube is less than the length of the hollow drill rod, and the length of the orifice tube is greater than the length of the sealing sleeve; multiple rings are welded inside the orifice tube, the material of the rings is the same as the material of the orifice tube, and the inner diameter of the rings is the same as the outer diameter of the hollow drill rod, so as to ensure the insertion fit between the hollow drill rod and the rings.

[0011] Furthermore, the toothed drill bit uses 10 alloy teeth, which are used to rotate and cut the steel shell of the tunnel boring machine under the drive of the rotating head at the tail of the hollow drill rod.

[0012] Furthermore, flanges are provided at both ends of the orifice pipe and the sealing sleeve; the flange at the head of the sealing sleeve is welded to the inner wall of the tunnel boring machine shell for positioning the core sampling position; the outer circumference of the flange at the tail of the sealing sleeve has several equidistant connecting bolt holes, and the connecting bolt holes are connected to the flange at the tail of the orifice pipe by long bolts.

[0013] Furthermore, a tail end cover plate is connected to the flange side of the sealing sleeve via a connecting lock. A polyurethane injection hole is opened at the center of the tail end cover plate. After the core is extracted, the tail end cover plate is closed, and polyurethane is injected through the polyurethane injection hole to prevent the pressure inside and outside the tunnel boring machine from connecting.

[0014] Furthermore, after the end cap is put on, tallow packing is wrapped around the outside of the orifice tube to achieve a seal inside the sealing sleeve.

[0015] Secondly, the present invention also provides a construction method for preventing block falling during the freezing reinforcement of the casing of a tunnel boring machine under riverbed, the construction method comprising:

[0016] S1. Mark the area to be drilled on the shield machine shell, and install and fix the sealing sleeve, orifice pipe and hollow drill rod in sequence to realize the connection of equipment structural components.

[0017] S2. Start the core drilling machine, inject cooling water through the external cooling water pipe to cool the toothed drill bit, control the insertion depth of the borehole pipe, and drill in a cyclic manner until the predetermined depth is reached. Then stop drilling and pull back the hollow core drill rod.

[0018] S3. Remove the drilled shield casing and seal the sealing sleeve and orifice pipe after extracting the hollow drill rod.

[0019] Furthermore, markings are made at the locations where holes will be drilled on the tunnel boring machine casing, and the sealing sleeve, borehole pipe, and hollow drill rod are installed and fixed in sequence to achieve the connection of the equipment structural components, including:

[0020] S11. Mark the center point of the tunnel boring machine shell at the opening location using colored paint.

[0021] S12. Weld the sealing sleeve head flange tightly against the inner wall of the tunnel boring machine casing.

[0022] S13. The flange at the end of the orifice pipe and the flange at the end of the sealing sleeve are connected firmly with long bolts, and the long bolts are tightened with nuts on both sides.

[0023] S14. Insert the hollow drill rod into the borehole pipe to complete the positioning, connect the rotating head to the tail of the hollow drill rod, and connect the external cooling water pipe to the water injection hole.

[0024] Further, the core drilling rig is started, and cooling water is injected through an external cooling water pipe to cool the toothed drill bit. The insertion depth of the borehole pipe is controlled, and drilling is carried out through circulation until the predetermined depth is reached. Drilling is then stopped and the hollow core drill rod is withdrawn, including:

[0025] S21. Open the rotating head at the tail of the hollow drill rod. As the hollow drill rod drills, open the external cooling water pipe to inject cooling water. The cooling water flows back from the gap between the orifice pipe and the hollow drill rod and overflows from the tail of the orifice pipe into the tunnel boring machine.

[0026] S22. After the hollow drill rod has drilled to the preset starting distance, stop the machine, loosen the long bolt connecting the orifice pipe and the sealing sleeve, insert the orifice pipe to the depth of the hollow drill rod, and repeat this process until the hollow drill rod has drilled to the final preset end distance of the shield machine shell.

[0027] S23. When the hollow drill rod reaches the preset end distance, close the external cooling water pipe and continue drilling using the coolant stored inside the hollow drill rod through the orifice pipe. After drilling to the preset end distance, the hollow drill rod connects with the external strata and continues drilling to the external strata for the preset strata distance. The external water and soil pressure is used to push the drilled shield machine shell back up.

[0028] S24. When the hollow drill pipe reaches the preset formation distance, stop drilling and withdraw the hollow drill pipe.

[0029] Furthermore, after removing the drilled tunnel boring machine casing and extracting the hollow drill rod, the sealing sleeve and orifice pipe are sealed, including:

[0030] S31. After the hollow drill rod and core sample are completely removed, close the end cover plate connected to the flange at the tail of the sealing sleeve and secure it tightly with bolts.

[0031] S32. Inject polyurethane foam into the orifice tube and sealing sleeve through the polyurethane injection hole at the center of the tail end cover plate.

[0032] S33. Use tallow packing to wrap around the outside of the orifice pipe in layers, and then insert the wrapped layers into the sealing sleeve until it is completely filled without any gaps, thus achieving a seal.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. By adding a clamp inside the borehole pipe, the drilled-out shield shell is prevented from falling into the external strata and jamming the subsequent drilling of the drill bit during the drilling process; at the same time, after the drilling length reaches the thickness of the shield shell, the hollow drill rod continues to drill 20cm into the strata and then stops drilling. The external water and soil pressure pushes the drilled-out shield shell back into the shield machine, so as to remove the shield shell and prevent it from falling into the external strata and affecting the subsequent drilling of the freezing pipe.

[0035] 2. The design of the hoop structure serves two purposes: ① During the core drilling process of the tunnel boring machine (TBM) steel shell, the hollow drill rod experiences significant irregular vibrations, which can easily cause it to deviate during drilling. Adding hoop rings constrains the hollow drill rod, ensuring it maintains its predetermined drilling path. ② When the hollow drill rod penetrates the shield shell for core extraction, the removed TBM shell retracts under external water and soil pressure. During this retraction, the hollow drill rod may carry away external sediment, causing the extracted core sample to deviate and slip into the external strata, resulting in core extraction failure. By adding three hoop rings inside the borehole pipe, since the inner diameter of the hoop rings is approximately the same as the outer diameter of the core sample, even if the core sample deviates within the core extraction pipe, it will be blocked by the hoop rings, preventing it from slipping into the external strata.

[0036] 3. This invention is simple and convenient to operate. It only requires setting a chuck inside the drilling rig to hold the drilled shield shell in place. After drilling is completed, the drilling rig can be stopped for 5-10 seconds before being lifted. It also has a wide range of applications, not only applicable to drilling inside tunnel boring machines, but also to drilling and preventing the shield shell from falling into other underground structures. In addition, this invention has good performance. Since it requires minimal modification to existing drilling rigs, it will not affect the use of the drilling rig. At the same time, the design of adding a chuck and the improved construction process can ensure that the shield shell is completely removed. Attached Figure Description

[0037] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 This is a schematic diagram of the connection between the hollow core drill rod, sealing sleeve and orifice pipe in a device for preventing falling blocks from the inner opening of a shield tunneling machine under the riverbed, according to an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of a sealing sleeve and hollow drill rod used in a device for preventing falling blocks from being opened inside the casing of a tunnel boring machine under the riverbed, according to an embodiment of the present invention.

[0040] Figure 3This is a top view of the relative relationship between the hollow core drill rod, the orifice pipe and the external sealing sleeve in a device for preventing falling blocks from the inner opening of a shield tunneling machine under the riverbed, according to an embodiment of the present invention.

[0041] Figure 4 This is a top view of the relative relationship between the hollow core drill rod and the orifice pipe in an anti-falling block device for freezing reinforcement of the casing of a tunnel boring machine under the riverbed, according to an embodiment of the present invention.

[0042] Figure 5 This is a top view of the front end of the orifice pipe in an anti-falling block device with an opening inside the casing of a tunnel boring machine for freezing reinforcement according to an embodiment of the present invention.

[0043] Figure 6 This is a top view of the front end of a sealing sleeve in an anti-falling block device with an opening inside the casing of a tunnel boring machine for freezing reinforcement according to an embodiment of the present invention.

[0044] Figure 7 This is a schematic diagram of drilling the inner shell of a tunnel boring machine (TBM) in an equipment for preventing falling blocks by opening holes in the inner shell of a TBM for freezing reinforcement under riverbed, according to an embodiment of the present invention.

[0045] Figure 8 This is a schematic diagram of the end cover plate of the sealing sleeve in the anti-falling block equipment with opening in the casing of a tunnel boring machine under riverbed, according to an embodiment of the present invention.

[0046] Figure 9 This is an improved stress analysis of the steel shell during the drilling process of a hollow drill pipe according to an embodiment of the present invention;

[0047] Figure 10 This is a schematic diagram of the multi-drill rig quincunx drilling sequence according to an embodiment of the present invention;

[0048] Figure 11 This is a stress analysis of the steel shell during the drilling process of the drill pipe according to an embodiment of the present invention;

[0049] Figure 12 This is a flowchart of a construction method for preventing block falling during drilling inside a tunnel boring machine (TBM) under riverbed and for strengthening the machine shell to prevent block falling, according to an embodiment of the present invention.

[0050] Reference numerals: 1. Hollow drill rod; 2. Toothed drill bit; 3. Orifice pipe; 4. Sealing sleeve; 5. Water injection hole; 6. External cooling water pipe; 7. Ring clamp; 8. Flange; 9. Connecting bolt hole; 10. Connecting lock; 11. Tail end cover plate; 12. Polyurethane injection hole; 13. Butter packing. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] Please see Figures 1-8 A device for preventing blockages from falling out of the casing of a tunnel boring machine (TBM) under riverbed during cryogenic reinforcement is provided. The device includes a hollow drill rod 1 with a toothed drill bit 2 at its head. To stabilize the hollow drill rod 1 and facilitate core extraction, a borehole pipe 3 is fitted around the outer circumference of the hollow drill rod 1, and a sealing sleeve 4 is fitted around the outer circumference of the borehole pipe 3 to ensure the tightness of the drilling process and prevent pressure loss when the TBM is connected to the outside. A water injection hole 5 is provided at the tail of the hollow drill rod 1, and an external cooling water pipe 6 is installed inside the water injection hole 5 to inject cooling water to cool the toothed drill bit 2.

[0053] In one embodiment, the length of the orifice tube 3 is less than the length of the hollow drill rod 1, and the length of the orifice tube 3 is greater than the length of the sealing sleeve 4; multiple rings 7 are welded inside the orifice tube 3, the material of the rings 7 is the same as the material of the orifice tube 3, and the inner diameter of the rings 7 is the same as the outer diameter of the hollow drill rod 1, so as to ensure the insertion fit between the hollow drill rod 1 and the rings 7.

[0054] It should be noted that, by Figures 1-3 It can be seen that the hollow drill rod 1 has a hollow structure, and its head is composed of an alloy toothed drill bit 2. A borehole tube 3 is installed outside the hollow drill rod 1. The borehole tube 3 serves as a stabilizing device and a core-taking device for the hollow drill rod 1; its length is shorter than the hollow drill rod 1 but longer than the outermost sealing sleeve 4. The borehole tube 3 is made of Q355B steel. Figures 3-5 As shown, a hollow drill rod 1 is inserted inside. To prevent the drilled shield core sample from falling into the external strata, and to limit the deviation of the hollow drill rod 1 due to vibration during drilling, three rings 7 are welded inside the borehole pipe 3. The material of the rings 7 is the same as that of the borehole pipe 3, and the thickness of the rings 7 is 2-3 cm. The inner diameter of the rings 7 is the same as the outer diameter of the hollow drill rod 1, ensuring that the hollow drill rod 1 can be inserted precisely into the rings.

[0055] In one embodiment, the toothed drill bit 2 uses 10 alloy teeth to rotate and cut the steel shell of the tunnel boring machine under the drive of the rotating head at the tail of the hollow drill rod 1.

[0056] It should be noted that, by Figure 3As shown in the top view of the relative relationship between the hollow drill rod 1 and the orifice pipe 3, the high-strength alloy toothed drill bit has 10 alloy teeth, which rotate and cut the steel shell of the tunnel boring machine under the drive of the rotating head at the tail of the hollow drill rod 1. Except for the alloy teeth, the rest of the hollow drill rod 1 is made of Q355B steel. In order to reduce the large amount of heat generated by the strong friction between the alloy teeth and the steel shell of the tunnel boring machine during drilling, which would cause the alloy to soften or fatigue and affect the core sampling efficiency, an external cooling water pipe 6 is connected to the tail of the core drill to inject cooling water into the head of the core drill to cool the drill bit.

[0057] In one embodiment, flanges 8 are provided at both ends of the orifice pipe 3 and the sealing sleeve 4; the flange 8 located at the head of the sealing sleeve 4 is welded to the inner wall of the tunnel boring machine shell for positioning the core sampling position; a number of equidistant connecting bolt holes 9 are opened on the outer edge of the flange 8 located at the tail of the sealing sleeve 4, and the connecting bolt holes 9 are connected to the flange 8 at the tail of the orifice pipe 3 by long bolts.

[0058] It should be noted that, as Figures 1-2 As shown, on the outermost layer of the hollow drill rod 1, to ensure the tightness of the drilling rig during the drilling process, the outermost part of this device is a sealing sleeve 4. The sealing sleeve 4 is made of Q355B steel and is mainly used to connect the shield machine shell and the orifice pipe 3 to prevent the drilling rig from losing pressure due to external communication with the shield machine during the drilling process. There are flanges 8 at both the front and rear of the sealing sleeve 4.

[0059] like Figure 6 As shown, the flange 8 at the front of the sealing sleeve 4 is tightly fitted to the inner shell of the tunnel boring machine. It has no bolt holes and is fixed to the inner wall of the tunnel boring machine shell by welding, used for positioning the core sampling location. Figure 8 As shown, the sealing sleeve 4 has bolt holes 9 on the tail flange 8, which are bolted to the orifice pipe 3 tail flange 8. Since the orifice pipe 3 is longer than the sealing sleeve 4, a long bolt is used for the connection. At the same time, during core sampling, the orifice pipe 3 can be inserted between the shield machine shell and the extracted core sample by adjusting the bolt length.

[0060] In one embodiment, a tail end cover plate 11 is connected to one side of the flange 8 at the tail end of the sealing sleeve 4 via a connecting latch 10. A polyurethane injection hole 12 is opened at the center of the tail end cover plate 11. After the core is extracted, the tail end cover plate 11 is covered, and polyurethane is injected through the polyurethane injection hole 12 to prevent the internal and external pressures of the tunnel boring machine from connecting. After the tail end cover plate 11 is covered, tallow packing 13 is wrapped around the outside of the orifice pipe 3 to achieve a seal inside the sealing sleeve 4.

[0061] It should be noted that a tail end cover plate 11 is also connected to the flange 8 at the tail of the sealing sleeve 4. The tail end cover plate 11 has polyurethane injection holes 12. After the core drill is completed and the core is extracted, the tail end cover plate 11 is immediately placed on top, and polyurethane is injected into the sealing holes to prevent pressure connection between the inside and outside of the tunnel boring machine. Finally, grease packing 13 is wrapped around the outside of the orifice pipe 3 in multiple layers and then inserted into the sealing sleeve 4 until it is completely filled without gaps. This serves as a seal.

[0062] Please see Figure 12 The present invention also provides a construction method for preventing block falling during the construction of a frozen reinforcement machine shell for tunnel boring machines in riverbeds, the construction method comprising:

[0063] S1. Mark the area to be drilled on the shield machine shell, and install and fix the sealing sleeve 4, the orifice pipe 3 and the hollow drill rod 1 in sequence to realize the connection of the equipment structural components.

[0064] S2. Start the core drilling machine, inject cooling water through the external cooling water pipe 6 to cool the toothed drill bit 2, control the insertion depth of the borehole pipe 3, and drill in a cyclic manner until the predetermined depth is reached. Stop drilling and pull back the hollow core drill rod 1.

[0065] S3. Remove the drilled shield machine casing and seal the sealing sleeve 4 and the orifice pipe 3 after extracting the hollow drill rod 1.

[0066] In one embodiment, markings are made at the opening location on the tunnel boring machine casing, and the sealing sleeve 4, the orifice pipe 3, and the hollow drill rod 1 are installed and fixed sequentially to achieve the connection of the equipment structural components, including:

[0067] S11. Mark the center point of the tunnel boring machine shell at the opening location using colored paint.

[0068] S12. Weld the sealing sleeve 4 head flange 8 to the inner wall of the tunnel boring machine shell after they are tightly attached.

[0069] S13. Connect the flange 8 at the end of the orifice pipe 3 to the flange at the end of the sealing sleeve 4 with long bolts, and tighten the long bolts with nuts on both sides.

[0070] S14. Insert the hollow drill rod 1 into the borehole pipe 3 to complete the positioning, and connect the tail of the hollow drill rod 1 to the rotating head, and connect the external cooling water pipe 6 to the water injection hole 5.

[0071] In one embodiment, starting the core drilling machine, injecting cooling water through the external cooling water pipe 6 to cool the toothed drill bit 2, controlling the insertion depth of the borehole pipe 3, and drilling cyclically until a predetermined depth is reached, then stopping drilling and retracting the hollow core drill rod 1 includes:

[0072] S21. Open the rotating head at the tail of the hollow drill rod 1. As the hollow drill rod 1 drills in, open the external cooling water pipe 6 to inject cooling water. The cooling water flows back from the gap between the orifice pipe 3 and the hollow drill rod 1 and overflows from the tail of the orifice pipe 3 into the tunnel boring machine.

[0073] S22. After the hollow drill rod 1 has drilled to the preset starting distance, stop the machine and loosen the long bolt connecting the orifice pipe 3 and the sealing sleeve 4. Insert the orifice pipe 3 into the depth to which the hollow drill rod 1 has drilled, and repeat this process until the hollow drill rod 1 has drilled to the final preset end distance of the shield machine shell.

[0074] S23. When the hollow drill rod 1 reaches the preset end distance, close the external cooling water pipe 6, and continue drilling using the coolant stored inside the hollow drill rod 1 through the orifice pipe 3. After drilling to the preset end distance, the hollow drill rod 1 connects with the external stratum and continues to drill to the external stratum for the preset stratum distance, and uses the external water and soil pressure to push back the drilled shield machine shell.

[0075] S24. When the hollow drill rod 1 reaches the preset formation distance, stop drilling and pull back the hollow drill rod 1.

[0076] In one embodiment, removing the drilled tunnel boring machine casing and sealing the sealing sleeve 4 and the orifice pipe 3 after extracting the hollow drill rod 1 includes:

[0077] S31. After the hollow drill rod 1 and the core sample are completely removed, close the tail end cover plate 11 connected to the tail flange 8 of the sealing sleeve 4 and secure it tightly with bolts.

[0078] S32. Inject polyurethane foam into the orifice tube 3 and sealing sleeve 4 through the polyurethane injection hole 12 at the center of the tail cover plate 11.

[0079] S33. Use tallow packing 13 to wrap around the outside of the orifice tube 3 in layers, and then insert the wrapped layers into the sealing sleeve 4 until it is completely filled without any gaps, thus achieving a seal.

[0080] The following describes, with reference to specific embodiments, a device for preventing block falling from the inner shell of a tunnel boring machine under riverbed through a freeze-strengthening process, and its construction method.

[0081] like Figure 7As shown (the bottom arc-shaped surface represents the tunnel boring machine (TBM) casing), before officially commencing core sampling using this device, the structural components must be connected. Specifically: Mark the center point of the area where the TBM casing will require drilling with colored paint. Then, weld the front flange 8 of the sealing sleeve 4 tightly to the inner wall of the TBM casing. Next, securely connect the flange 8 at the bottom of the orifice pipe 3 to the flange 8 at the bottom of the sealing sleeve 4 using bolts (the length of the orifice pipe 3 is greater than that of the sealing sleeve. During the flange 8 connection process, long bolts are inserted sequentially into the bolt holes on both the sealing sleeve 4 and the orifice pipe 3 flanges, and tightened with nuts on both sides). Finally, insert the core drilling rig (hollow core drill rod 1) into the orifice pipe 3 to complete the positioning. The rotating head is connected to the bottom of the core drilling rig, and the external cooling water pipe 6 is connected to the side.

[0082] During the formal core sampling operation, the core drilling rig (hollow drill rod 1 driven by a rotary head) is first started. As the rig drills, the external cooling water pipe 6 is opened to inject water into the drill bit to cool it. The sealing sleeve 4 is well-sealed, and the injected cooling water flows back from the gap between the orifice pipe 3 and the hollow drill rod 1, overflowing from the tail end of the orifice pipe 3 into the tunnel boring machine. After the rig has drilled a certain distance (generally every 10cm), the machine is stopped, the bolts connecting the orifice pipe 3 and the sealing sleeve 4 are loosened, and the orifice pipe 3 is inserted to the drilling depth (the wall thickness of the orifice pipe needs to be slightly increased in all directions during drilling to ensure insertion). This process is repeated until the rig has drilled the last 3cm of the shield. At this point, the external cooling water pipe 6 is closed, allowing the rig to continue drilling using the cooling water remaining between the orifice pipe 3 and the hollow drill rod 1. After drilling the last 3cm of the shield shell, the hollow drill rod 1 is connected to the external strata, and drilling continues for another 10-20cm into the external strata. The external water and soil pressure is used to push the drilled shield shell back up. When the predetermined depth is reached, drilling stops and the hollow drill rod 1 is pulled back.

[0083] After removing the drilled shield machine casing, to prevent external water and soil pressure from connecting with the internal pressure of the shield machine, the sealing sleeve 4 and the orifice pipe 3 need to be sealed immediately after the hollow drill rod 1 is extracted. Specifically, the tail flange 8 of the sealing sleeve 4 is connected to the tail end cover plate 11. After the hollow drill rod 1 and the core sample are removed, the bolts on the orifice pipe 3 and the flange of the sealing sleeve 4 should be tightly connected. The tail end cover plate 11 of the sealing sleeve 4 should be closed promptly and tightly bolted. Then, polyurethane foam should be injected into the sealed orifice pipe 3 and sealing pipe 4 through the polyurethane injection hole 12 at the top of the tail end cover plate 11. Figure 8 As shown.

[0084] This technology requires little space and allows for simultaneous construction at multiple locations within the tunnel boring machine. The specific construction procedures are as follows: Figure 10 As shown, a quincunx-shaped skip-hole construction technique is adopted to improve the core extraction speed of the tunnel boring machine shell.

[0085] This invention not only modifies the structure of the original core drilling drill bit, but also changes its working principle during the entire core drilling process of the tunnel boring machine's steel shell. Specifically, when the drill bit is 50mm away from completing the drilling, the external water pump of the hollow drill rod 1 is shut off, and the ground pressure is used to back-pressure water to cool the drill bit and continue drilling the last 50mm. After drilling is completed, the hollow drill rod 1 is pushed 200mm further into the external strata, and the ground water and soil pressure is used to fully push the drilled-down tunnel boring machine steel shell back into the drill rod, preventing the tunnel boring machine steel shell from falling into the external strata.

[0086] Its implementation principle is characterized as follows:

[0087] Drilling holes inside the tunnel boring machine (TBM) casing is most prone to causing the steel casing to break through and fall into the external strata, particularly at the bottom of the TBM. At this point, due to the downward-sloping drilling, the steel block slides downwards under its own weight and the impact force of water within the drill rod, detaching from the drill rod. Using this method for core sampling, the water pump is shut off near the end of drilling, eliminating the risk of the steel casing slipping due to water impact. After drilling is complete, the hollow drill rod 1 continues to be pushed into the strata, using water and soil pressure to balance the downward component of the steel block's weight along the drill rod. This method ultimately prevents the steel casing from slipping.

[0088] The formula is represented as follows:

[0089] like Figure 11 As shown, based on the force analysis of the steel shell during the drilling process, the resultant force of the drilled shield shell along the drill rod downwards during the drilling process of hollow drill rod 1 is:

[0090] F 合 =Gsinθ+F-μGcosθ

[0091] In the formula, G is the weight of the drilled steel shell, F is the impact force of the drill rod and cooling water on the steel shell, μ is the coefficient of friction between the steel shell and the drill rod, and θ is the angle between the drill rod and the horizontal plane.

[0092] Generally speaking, the coefficient of friction between steel is 0.15. Therefore, when the drilling angle θ is 15°, the downward force of the steel shell is greater than the frictional force, and the steel shell is prone to slipping.

[0093] After adopting this method, when the drill rod is 50mm away from the completion of drilling, the external water pump of the hollow drill rod 1 is turned off. At this time, the resultant force of the shield shell diagonally downward along the drill rod is:

[0094] F 合 =Gsinθ-μGcosθ;

[0095] In an ideal state, the shield is only affected by its own weight and friction.

[0096] like Figure 9As shown (the upper layer is water, the lower layer is soil), the force analysis of the steel shell during the drilling process of the improved drill rod of this invention is as follows: After the hollow drill rod 1 is drilled through, it is pushed 200mm further into the external strata. At this time, the resultant force on the shield shell is:

[0097] F 合 =Gsinθ-μGcosθ-M;

[0098] In the formula, M represents the resultant force of external soil and water, which is expressed using Rankine's active earth pressure formula:

[0099]

[0100] In the formula, γ is the weight of the external soil, Z is the elevation difference between the ground and the borehole center, and K a Where is the active earth pressure coefficient, and C is the cohesion. In the formula... in It is the internal friction angle.

[0101] By F 合 From the equation = Gsinθ - μGcosθ - M, we can see that when the water pump is turned off, the friction coefficient μ increases. Simultaneously, because of the added component of the combined force of the external water and soil, the component of the force acting on the drilled steel shell along the hollow drill rod 1, pointing downwards, is much smaller than the component acting before any intervention was taken. Under these circumstances, the drilled steel shell is less likely to slip off the drill rod.

[0102] In summary, by adding a locking mechanism inside the borehole pipe 3, the drilled-out shield shell is prevented from falling into the external strata and jamming the subsequent drilling during the tunnel boring machine (TBM) shell drilling process. Simultaneously, after the drilling length reaches the shield shell thickness, the hollow drill rod 1 continues drilling 20cm into the strata before stopping. External water and soil pressure pushes the drilled-out shield shell back into the TBM, achieving the goal of removing the shield shell and preventing it from falling into the external strata and affecting subsequent freezing pipe drilling. This invention is simple and convenient to operate, requiring only a locking mechanism inside the drilling rig to hold the drilled shield shell in place. After drilling is completed, the drilling rig is stopped for 5-10 seconds before being lifted. It also has a wide range of applications, not only applicable to drilling inside TBMs but also to drilling and preventing falling debris from other underground structures. Furthermore, this invention has good performance, requiring minimal modification to existing drilling rigs and not affecting their operation. The added locking mechanism, combined with the improved construction process, ensures the complete removal of the TBM steel shell.

[0103] The key improvement of this invention lies in the modification of the interior of the orifice pipe 3. Three ring clamps 7 are welded inside the orifice pipe 3. These ring clamps 7 are made of Q355B steel, rolled into rings and welded to the inner wall of the orifice pipe 3. After welding, the inner diameter of the ring clamps 7 is consistent with the outer diameter of the hollow drill rod 1. The addition of these ring clamps mainly serves two purposes: ① During the drilling process of the hollow drill rod 1 driven by the drilling rig into the shield machine's steel shell for core extraction, significant irregular vibrations occur. These irregular vibrations can easily cause the hollow drill rod 1 to deviate during drilling. The addition of the ring clamps 7 constrains the hollow drill rod 1, ensuring that it maintains the set drilling path throughout the drilling process. ② During the process of the hollow drill rod 1 penetrating the shield shell for core extraction, the removed shield machine shell retracts under the action of external water and soil pressure. At this time, the hollow drill rod 1 will carry away external mud and sand during the retraction process, causing the extracted core sample to deviate, slip into the external strata, and fail to extract the core. By adding three rings 7 inside the borehole tube 3, since the inner diameter of the rings 7 is basically the same as the outer diameter of the core sample, even if the core sample is displaced inside the core tube, it will still be blocked by the rings 7 and will not slip into the external strata.

[0104] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

Claims

1. A device for preventing falling blocks from being cut into the inner casing of a tunnel boring machine used for cryogenic reinforcement, characterized in that, The equipment includes a hollow drill rod (1), and the head of the hollow drill rod (1) is provided with a toothed drill bit (2). In order to achieve the stabilization and core extraction of the hollow drill rod (1), the hollow drill rod (1) is fitted with a borehole pipe (3) on the outer circumference, and the borehole pipe (3) is fitted with a sealing sleeve (4) on the outer circumference to ensure the tightness of the drilling process and prevent the shield machine from losing pressure when connected to the outside. The hollow drill rod (1) has a water injection hole (5) at its tail end. An external cooling water pipe (6) is installed inside the water injection hole (5) to inject cooling water to cool the toothed drill bit (2). Flanges (8) are provided at both ends of the orifice tube (3) and the sealing sleeve (4). The flange (8) located at the head of the sealing sleeve (4) is welded to the inner wall of the shield machine shell for positioning the core sampling position; The flange (8) located at the tail of the sealing sleeve (4) has several equidistantly arranged connecting bolt holes (9) on its outer circumference. The connecting bolt holes (9) are connected to the flange (8) at the tail of the orifice pipe (3) by long bolts.

2. The anti-falling block equipment for the internal opening of the casing of a tunnel boring machine for freezing reinforcement under riverbeds, as described in claim 1, is characterized in that... The length of the orifice tube (3) is less than the length of the hollow drill rod (1), and the length of the orifice tube (3) is greater than the length of the sealing sleeve (4); Multiple rings (7) are welded inside the orifice tube (3). The material of the rings (7) is the same as that of the orifice tube (3), and the inner diameter of the rings (7) is the same as the outer diameter of the hollow drill rod (1) to ensure the insertion fit between the hollow drill rod (1) and the rings (7).

3. The anti-falling block equipment for the internal opening of the casing of a tunnel boring machine for freezing reinforcement under riverbeds, as described in claim 1, is characterized in that... The toothed drill bit (2) uses 10 alloy teeth and is used to rotate and cut the steel shell of the tunnel boring machine under the drive of the rotating head at the tail of the hollow drill rod (1).

4. The anti-falling block equipment for the internal opening of the casing of a tunnel boring machine for freezing reinforcement under riverbed, as described in claim 3, is characterized in that... The flange (8) at the tail end of the sealing sleeve (4) is connected to a tail end cover plate (11) by a connecting buckle (10). A polyurethane injection hole (12) is opened at the center of the tail end cover plate (11). After the core is extracted, the tail end cover plate (11) is covered and polyurethane is injected through the polyurethane injection hole (12) to prevent the pressure inside and outside the tunnel boring machine from being connected.

5. The anti-falling block equipment for the internal opening of the casing of a tunnel boring machine for freezing reinforcement under riverbed, as described in claim 4, is characterized in that... After the tail end cover plate (11) is put on, the outside of the orifice tube (3) is wrapped with tallow packing (13) to achieve the sealing inside the sealing sleeve (4).

6. A method for constructing an anti-sinking device for freezing reinforcement of the casing of a tunnel boring machine under riverbed, used to implement the construction of the anti-sinking device for freezing reinforcement of the casing of a tunnel boring machine under riverbed as described in any one of claims 1-5, characterized in that, The construction method includes: S1. Mark the opening location on the shield machine shell, and install and fix the sealing sleeve (4), the orifice pipe (3) and the hollow drill rod (1) in sequence to realize the connection of the equipment structural components. S2. Start the core drilling machine, inject cooling water through the external cooling water pipe (6) to cool the toothed drill bit (2), control the insertion depth of the orifice pipe (3), and drill in a cycle until the predetermined depth is reached. Stop drilling and pull back the hollow core drill rod (1). S3. Remove the drilled shield machine casing, and after pulling out the hollow drill rod (1), seal the sealing sleeve (4) and the orifice pipe (3).

7. A construction method for preventing block falling during freezing reinforcement of the casing of a tunnel boring machine under riverbed, as described in claim 6, is characterized in that... The process of marking the area to be drilled on the shield machine casing, and then sequentially installing and fixing the sealing sleeve (4), the orifice pipe (3), and the hollow drill rod (1) to achieve the connection of the equipment structural components includes: S11. Mark the center point of the tunnel boring machine shell at the opening location using colored paint. S12. Weld the sealing sleeve (4) head flange (8) to the inner wall of the shield machine shell after they are tightly attached. S13. The flange (8) at the end of the orifice pipe (3) and the flange at the end of the sealing sleeve (4) are connected firmly with long bolts, and the long bolts are tightened with nuts on both sides. S14. Insert the hollow drill rod (1) into the borehole pipe (3) to complete the positioning, and connect the tail of the hollow drill rod (1) to the rotating head, and connect the external cooling water pipe (6) to the water injection hole (5).

8. A construction method for preventing block falling during freezing reinforcement of the casing of a tunnel boring machine under riverbed, as described in claim 6, is characterized in that... The process of starting the core drilling machine, injecting cooling water through the external cooling water pipe (6) to cool the toothed drill bit (2), controlling the insertion depth of the borehole pipe (3), and drilling in a cyclic manner until the predetermined depth is reached, stopping drilling and withdrawing the hollow core drill rod (1) includes: S21. Open the rotating head at the tail of the hollow drill rod (1). As the hollow drill rod (1) drills in, open the external cooling water pipe (6) to inject cooling water. The cooling water flows back from the gap between the orifice pipe (3) and the hollow drill rod (1) and overflows from the tail of the orifice pipe (3) into the tunnel boring machine. S22. When the hollow drill rod (1) has drilled to the preset starting distance, stop the machine and loosen the long bolt connecting the orifice pipe (3) and the sealing sleeve (4). Insert the orifice pipe (3) into the depth to which the hollow drill rod (1) has drilled. Repeat this process until the hollow drill rod (1) has drilled to the final preset end distance of the shield machine shell. S23. When the hollow drill rod (1) reaches the preset end distance, close the external cooling water pipe (6) and continue drilling using the coolant stored inside the hollow drill rod (1) through the orifice pipe (3). After drilling to the preset end distance, the hollow drill rod (1) connects with the external stratum and continues to drill to the external stratum for the preset stratum distance. It also uses the external water and soil pressure to push the drilled shield machine shell back up. S24. When the hollow drill pipe (1) reaches the preset formation distance, stop drilling and pull back the hollow drill pipe (1).

9. A construction method for preventing block falling during freezing reinforcement of the casing of a tunnel boring machine under riverbed, as described in claim 6, is characterized in that... The step of removing the drilled shield machine casing and sealing the sealing sleeve (4) and the orifice pipe (3) after pulling out the hollow drill rod (1) includes: S31. After the hollow drill rod (1) and core sample are completely removed, close the tail end cover plate (11) connected to the tail flange (8) of the sealing sleeve (4) and secure it tightly with bolts. S32. Inject polyurethane foam into the orifice tube (3) and sealing sleeve (4) through the polyurethane injection hole (12) at the center of the tail end cover plate (11). S33. Use tallow packing (13) to wrap around the outside of the orifice tube (3) in circles. After wrapping multiple layers, insert it into the sealing sleeve (4) until it is completely filled without any gaps, thus achieving a seal.

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