Replacement method of slurry discharge pipe and knife gate valve near the slurry shield

Abstract

The present invention discloses a method for replacing the near-end slurry discharge pipe and knife gate valve of a slurry shield. By adding stone powder and establishing a mud film at the slurry gate, the sealing of the slurry gate is ensured, and the high slurry pressure of the slurry bin and the stratum is blocked from entering the tunnel, so that the air cushion bin can realize normal pressure and a good working environment is provided for replacing the near-end knife gate valve in the shield body, and the problem of poor sealing of the slurry gate under high water pressure environment is solved, so that the replacement of worn parts of the slurry shield in hard rock can be carried out in a safe environment. The present invention solves the problem of high construction risk when the shield machine is directly shut down to replace the slurry pipe and other parts in hard rock because the slurry bin, the stratum and the shield body are connected.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and in particular to a method for replacing a proximal slurry discharge pipe and a knife gate valve of a slurry shield. Background Art

[0002] When the slurry shield is excavating in the hard rock section, the slurry pipe, knife gate valve and hydraulic ball valve are seriously worn. If the slurry pipe is worn thin and worn through, and the knife gate valve and hydraulic ball valve are damaged and cannot be closed in time, the tunnel is at risk of being flooded, threatening the life and property safety of construction workers. In case of wear and tear, timely measures must be taken to maintain and replace them in time, especially the slurry pipe and knife gate valve at the front shield partition inside the shield body. They are the main barriers to protect the safety of shield excavation construction. If leakage occurs, the tunnel will be connected to the slurry bin and the stratum. It is necessary to ensure that the slurry pipe and knife gate valve near the front shield partition inside the shield body are in good operating condition.

[0003] Before the start of the slurry shield, the slurry discharge pipe inside the shield is generally new, with wear-resistant welding inside, which is easy to replace in the factory or before the start. However, it is easy to wear when excavating in the hard rock section, and the replacement process must be carried out under normal pressure and waterless environment. When excavating in hard rock, the mud door is worn by stones to a certain extent, resulting in the mud door not being able to close tightly or the mud door being sealed. Directly stopping the machine for replacement in hard rock, because the mud water tank, the formation and the shield body are connected, the construction risk is high. Summary of the invention

[0004] In order to overcome the defects of the prior art, a method for replacing the proximal slurry discharge pipe and knife gate valve of a slurry shield is provided to solve the problem of high construction risk when the shield machine is directly shut down to replace mud pipes and other components in hard rock due to the connection between the mud and water tank, the formation and the shield body.

[0005] In order to achieve the above object, a method for replacing a slurry discharge pipe and a knife gate valve at the proximal end of a slurry shield is provided, comprising the following steps:

[0006] When the slurry shield excavates in hard rock and its parts are worn and need to be replaced, the slurry door of the slurry shield and the lower slurry discharge pipe located below the slurry door are closed, and the upper slurry discharge pipe located above the slurry door is opened, so that the stone powder excavated by the cutter head of the slurry shield from the hard rock is deposited at the bottom of the slurry bin to form a plugging layer, and the plugging layer covers the slurry door;

[0007] Mixing high viscosity mud, wherein the high viscosity mud has a viscosity of 40 to 60 seconds;

[0008] Injecting the high-viscosity mud into the mud and water tank to replace the low-viscosity mud in the mud and water tank to establish a plugging mud film at the mud gate;

[0009] After the plugging mud film is established, the mud gate is sealed, the mud and water tank balances the formation pressure, and the air cushion tank is connected with the shield and the tunnel to achieve normal pressure;

[0010] After the air cushion chamber is connected with the shield body and the tunnel to achieve normal pressure, the worn parts of the slurry shield are replaced.

[0011] Furthermore, the top of the sealing layer is 10 cm higher than the mud gate.

[0012] Furthermore, after the blocking mud film is established, the air cushion chamber is drained and depressurized step by step, and the sealing effect of the blocking mud film on sealing the mud door is tested.

[0013] Furthermore, the wear parts include the lower slurry discharge pipe and the knife gate valve.

[0014] Furthermore, when replacing the worn parts, the lower slurry discharge pipe is replaced first, and then the knife gate valve is replaced, and the pipe opening of the new lower slurry discharge pipe is covered with a steel plate.

[0015] The beneficial effects of the present invention are that the method for replacing the proximal slurry discharge pipe and knife gate valve of a slurry shield of the present invention ensures the sealing of the slurry door by adding stone powder and establishing a mud film at the slurry door, blocks the high mud and water pressure of the slurry bin and the formation from entering the tunnel, provides a good working environment for achieving normal pressure in the air cushion bin and replacing the proximal knife gate valve in the shield body, solves the problem of poor sealing of the slurry door under high water pressure environment, and enables the replacement of worn parts of the slurry shield in hard rock to be carried out in a safe environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0017] Figure 1 It is a schematic structural diagram of a slurry shield according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the inventions. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] Reference Figure 1 As shown, the present invention provides a method for replacing a slurry discharge pipe and a knife gate valve at the proximal end of a slurry shield, comprising the following steps:

[0021] S1: When the slurry shield 1 excavates in hard rock and its parts are worn and need to be replaced, the slurry door 11 of the slurry shield 1 and the lower slurry discharge pipe located below the slurry door are closed, and the upper slurry discharge pipe located above the slurry door is opened, so that the stone powder excavated from the hard rock by the cutter head of the slurry shield is deposited at the bottom of the slurry bin A to form a sealing layer, and the sealing layer covers the slurry door.

[0022] Specifically, in this embodiment, the normal circulation of the slurry shield is:

[0023] The V12 hydraulic ball valve and V17 hydraulic ball valve are opened to let in slurry, the V34 backwash hydraulic ball valve is closed, and the V32 hydraulic ball valve is opened to discharge slurry. The slurry circulation carries the cutter head of the slurry shield to excavate the debris on the face.

[0024] In this embodiment, the circulation when the plugging layer is formed at the mud gate is:

[0025] The V12 hydraulic ball valve and V17 hydraulic ball valve are opened to let in slurry, the mud door is closed and the V32 hydraulic ball valve is closed, the V34 washing liquid hydraulic ball valve is opened, and the slurry is discharged using the slurry discharge port (upper slurry discharge pipe) which is higher than the mud door, so that the stone powder in the mud and water bin is deposited on the bottom of the mud and water bin.

[0026] As a preferred implementation manner, the top of the plugging layer is 10 cm higher than the mud gate, that is, the upper part of the plugging layer covers the top of the mud gate by at least 10 cm.

[0027] The advancement stroke of the slurry shield cylinder is determined by calculating the volume of stone powder 10 cm above the slurry gate. The slurry shield is slowly advanced to grind the tunnel face into stone powder, which is used to form a plugging layer in the slurry bin to block the slurry gate.

[0028] Specifically, the excavation parameters of the slurry shield are controlled as follows: the advancement speed is controlled at 1-2 mm / min, the cutter head speed is 1 r / min, and the advancement effective stroke is greater than 10 cm, that is, there is 10 cm of mud powder covering the mud door above the mud door. In actual excavation, the mud powder is discharged under the action of mud circulation and the advancement cylinder stroke is adjusted according to the pressure reduction inspection. During the advancement process, the lower slurry discharge pipe V32 is closed, and the upper slurry discharge pipe V34 is used to discharge slurry, so that fine sediment is deposited to the bottom of the excavation chamber as much as possible.

[0029] S2: Mix high viscosity mud, the viscosity of high viscosity mud is 40 to 60s.

[0030] In this embodiment, after two mud replacements, a plugging mud film is subsequently established at the mud gate.

[0031] S3: Injecting the high-viscosity mud into the mud and water tank to replace the low-viscosity mud in the mud and water tank to establish a plugging mud film at the mud gate.

[0032] Specifically, as the cutterhead advances, larger rocks may be deposited at the bottom of the excavation chamber, and the larger gap may cause water leakage at the mud gate. Therefore, a solution of establishing a mud film at the mud gate is adopted.

[0033] The first mud replacement: Mix high-viscosity mud with a viscosity of 45±5s on the ground, transport it to the tunnel with a battery car, connect the grouting pipe of the synchronous grouting pump to the reserved ball valve in the mud and water bin, and use the synchronous grouting pump to inject high-concentration mud. Open the upper grouting pipe V34 to allow the water in the mud and water bin to flow by itself, then quickly replenish the high-concentration mud and record the mud volume. This cycle continues until the newly injected mud is consistent with the discharged mud parameters. During this period, the ball valve at the bottom of the mud and water bin is used to measure the viscosity and specific gravity of the mud in the mud and water bin. If it is consistent with the viscosity of the new mud, it proves that the mud replacement is complete. After that, maintain the pressure of the mud and water bin for 2 to 3 hours, and slowly rotate the cutterhead (turn the cutterhead once every 15 minutes, and turn 2 circles each time).

[0034] Second mud replacement: Mix mud with a viscosity of 55±5s on the ground, transport it to the tunnel with a battery car, connect the grouting pipe of the synchronous grouting pump to the reserved ball valve in the mud and water bin, and use the synchronous grouting pump to inject high-concentration mud. Open the upper grouting pipe V34 to allow the water in the mud and water bin to flow by itself, then quickly replenish high-concentration mud and record the volume of mud. This cycle continues until the parameters of the newly injected mud are consistent with those of the discharged mud. During this period, the ball valve at the bottom of the mud and water bin is used to measure the viscosity and specific gravity of the mud in the mud and water bin. If it is consistent with the viscosity of the new mud, it proves that the mud replacement is complete. After that, maintain the pressure of the mud and water bin for 2 to 3 hours, and slowly rotate the cutterhead (turn the cutterhead once every 15 minutes, and turn 2 circles each time).

[0035] S4: After the blocking mud film is established, the air pressure in the air cushion chamber B of the slurry shield and the air pressure in the shield body of the slurry shield are balanced.

[0036] After two high-viscosity mud replacements are completed, check the sealing effect of the mud film of the mud door. Open the lower right connecting ball valve of the air cushion bin to release the pressure, estimate the water volume in the mud and water bin, and if the water flow becomes smaller or there is no water after all the water is discharged, it proves that the seal is good. If the water volume in the air cushion bin does not decrease after the water volume is discharged, it means that the mud door seal does not meet the conditions and is not suitable for replacement. Continue the above operation to reseal it.

[0037] After the sealing effect of the plugging mud film reaches the standard, balance the air pressure in the air cushion chamber and the shield body, and check the gas in the cabin every 10 minutes to maintain continuous ventilation. When there is no harmful gas and the mud door has a good water-stopping effect, the knife gate valve can be replaced.

[0038] When implementing the step of balancing the air pressure in the air cushion chamber of the slurry shield and the shield body of the slurry shield, the air cushion chamber is drained and depressurized step by step, and the sealing effect of the sealing mud film on sealing the slurry door is tested.

[0039] S5: After the air pressure in the air cushion chamber and the shield body reaches normal pressure, the worn parts of the slurry shield are replaced.

[0040] In this embodiment, the wear parts include a lower slurry discharge pipe and a knife gate valve 12. When replacing the wear parts, the lower slurry discharge pipe is replaced first, and then the knife gate valve is replaced, and the pipe opening of the new lower slurry discharge pipe is covered with a steel plate.

[0041] First, check the wear of the wear-resistant parts in the pipeline from the mud baffle 13 to the knife gate valve, explain the wear and use the prefabricated mud pipe (new lower discharge pipe) to outsource and weld it firmly; remove the knife gate valve and install it in time.

[0042] Replacement method of knife gate valve: first cut off the bracket fixing the iron pipe behind the knife gate valve, remove and disconnect the hose connected to the iron pipe, use the hoist to lift the iron pipe behind the knife gate valve, cut off the original knife gate valve bolts, pull the hoist to pull the iron pipe and knife gate valve out of the gap, take out the old knife gate valve, install the new knife gate valve in place, use new bolts to tighten and fix the iron pipe and knife gate valve, and loosen the hoist while tightening the bolts.

[0043] Specific protection methods for mud pipes: The mud pipelines are severely worn, so repair welding is done in advance at places prone to wear, steel plates are welded, and the wear-resistant layer is thickened. Places prone to wear are at various elbows.

[0044] V32 valve replacement method: Close the new knife gate valve, open the V32 ball valve, and remove the limit switch on the ball valve. For the hydraulic oil pipe, use a hoist to hang the ball valve, the hoist is stressed, then remove the bolts at both ends of the ball valve, put the ball valve on the shield tail through the hoist, and then lift the new ball valve through the hoist, align the steel chisel with the bolt hole, first install the bottom bolts, but do not tighten the bolts, then install the gasket, then install all the upper bolts, and tighten the bolts symmetrically to tighten the entire circle of the ball valve. After tightening, limit the ball valve and restore the hydraulic pipeline. Debug the ball valve. Finally, remove the hoist and transport the old ball valve out.

[0045] The method for replacing the proximal slurry discharge pipe and knife gate valve of the mud water shield of the present invention comprises the following steps: closing the mud gate, closing the V32 hydraulic ball valve, and introducing slurry at V17. The original backwashing V34 hydraulic ball valve (the pipe mouth is higher than the mud gate) is used as the slurry discharge pipe for excavation, and then the mud water shield is slowly advanced to grind the palm into stone powder, and the stone powder is left in the mud water bin to form a blocking layer, and the blocking layer is blocked at the mud gate (10 cm higher than the mud gate). After that, by estimating the amount of mud in the mud water excavation bin, the V34 hydraulic ball valve is opened, and the mud flows to the quarrying box by gravity, and then a high-concentration mud is injected through the slurry inlet pipe at V17 by using a synchronous grouting pump for replacement, and then a mud film is established at the mud gate. Finally, the lower right connecting ball valve of the air cushion bin is opened to release the pressure, and the water volume in the mud water bin is estimated. After all the water is discharged, the water flow becomes smaller or there is no water, proving that the sealing is good. Then, the air pressure is balanced, so that the proximal knife gate valve is replaced after the air cushion bin reaches normal pressure, and the proximal mud pipe is wrapped with a customized steel plate.

[0046] The method for replacing the proximal slurry discharge pipe and knife gate valve of a slurry shield of the present invention ensures the sealing of the slurry gate by adding stone powder and establishing a mud film at the slurry gate, blocks the high slurry pressure of the slurry bin and the stratum from entering the tunnel, provides a good working environment for achieving normal pressure in the air cushion bin and replacing the proximal knife gate valve in the shield body, solves the problem of poor sealing of the slurry gate under high water pressure environment, and enables the replacement of worn parts of the slurry shield in hard rock to be carried out in a safe environment.

[0047] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for replacing the proximal slurry discharge pipe and knife gate valve of a slurry shield, characterized in that: The following steps are involved: When the slurry shield excavates in hard rock and its parts are worn and need to be replaced, the slurry door of the slurry shield and the lower slurry discharge pipe located below the slurry door are closed, and the upper slurry discharge pipe located above the slurry door is opened, so that the stone powder excavated by the cutter head of the slurry shield from the hard rock is deposited at the bottom of the slurry bin to form a plugging layer, and the plugging layer covers the slurry door; Mixing high-viscosity mud, wherein the high-viscosity mud has a viscosity of 40 to 60 seconds; Injecting the high-viscosity mud into the mud and water tank to replace the low-viscosity mud in the mud and water tank to establish a plugging mud film at the mud gate; After the plugging mud film is established, the mud gate is sealed, the mud and water tank balances the formation pressure, and the air cushion tank is connected with the shield and the tunnel to achieve normal pressure; After the air cushion chamber is connected with the shield body and the tunnel to achieve normal pressure, the worn parts of the slurry shield are replaced. The worn parts include a lower slurry discharge pipe and a knife gate valve. When replacing the worn parts, the lower slurry discharge pipe is replaced first, and then the knife gate valve is replaced. The pipe mouth of the new lower slurry discharge pipe is covered with a steel plate.

2. The method for replacing the proximal slurry discharge pipe and knife gate valve of a slurry shield according to claim 1 is characterized in that: The top of the plugging layer is 10 cm higher than the mud gate.

3. The method for replacing the proximal slurry discharge pipe and knife gate valve of a slurry shield according to claim 1 is characterized in that: After the plugging mud film is established, the air cushion chamber is drained and depressurized step by step, and the sealing effect of the plugging mud film in sealing the mud door is tested.

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