Mud film material for shield under-pressure bin opening and tool changing construction and construction method

Abstract

The invention relates to the technical field of cutter replacement of a cutter head of a shield tunneling machine, and particularly discloses a mud film material and a construction method for shield pressurized bin opening and cutter replacement construction. The mud film material comprises 282.4 parts by weight of slaked lime; 141.2 parts by weight of calcium bentonite; 141.2 parts by weight of sodium bentonite; 735.15 parts by weight of water; 7.35 parts by weight of cellulose; and 58.57 parts by weight of water glass. And stable operation of the tunnel face can be ensured. The method comprises the following steps: stirring slaked lime, calcium bentonite, sodium bentonite, water and cellulose according to required parts by weight to obtain bentonite slurry; adding bentonite slurry water glass, and stirring to obtain bentonite mixed slurry; the bentonite mixed slurry is injected into the soil bin, and muck in the soil bin is replaced; injecting water glass into the soil bin to obtain composite clay mixed slurry; and forming a mud film on the tunnel face by compounding the clay mixed slurry. According to the method, disturbance to the stratum in the tunneling process of the shield tunneling machine can be reduced, and the stability of the stratum can be kept.

Description

Technical Field

[0001] The invention relates to the technical field of shield machine cutterhead tool replacement, and in particular to a mud film material and a construction method for use in shield machine pressure chamber opening and tool replacement construction. Background Art

[0002] When the burial depth of the shield cutter change stratum is only 9.1m, the burial depth is relatively shallow, and the stratum is a highly permeable and non-sealed stratum, and the original stratum has a large amount of gas loss, the conventional method of injecting bentonite to form a mud film on the face has poor self-stability and the gas loss is uncontrollable; because when the face is located in a shallow stratum, the surface settlement and disturbance have a more significant impact on the stability of the face, which may make it difficult for the mud film to form a stable support; in a highly permeable stratum, groundwater is easy to penetrate, which may dilute the bentonite slurry, reduce its viscosity and film-forming properties, and thus affect the stability and strength of the mud film; so now there is an urgent need for a new mud film material to solve the above problems. Summary of the invention

[0003] The invention provides a mud film material and a construction method for shield tunneling pressure opening and cutter changing construction, which can overcome certain or some defects of the prior art.

[0004] The mud film material used in shield tunneling pressure opening and cutting tool changing construction according to the present invention comprises the following components: Slaked lime, 282.4 parts by weight; Calcium bentonite, 141.2 parts by weight; Sodium bentonite, 141.2 parts by weight; Water, 735.15 parts by weight; cellulose, 7.35 parts by weight; and Water glass, 58.57 parts by weight.

[0005] According to the present invention, bentonite is a key component in the mud film material, and it has strong water absorption and expansion properties and adhesion properties; the combined use of calcium-based bentonite and sodium-based bentonite can form a more compact and stable mud film structure; compared with calcium-based bentonite, sodium-based bentonite has a higher water absorption rate and stronger adhesion, and can form a more solid mud film on the face of the tunnel; An appropriate amount of bentonite can ensure that the mud film has sufficient strength and stability to resist the pressure and disturbance of the formation. When the amount of calcium-based bentonite and sodium-based bentonite is 1:1, the performance of the mud film can be ensured to be optimal. Cellulose is a high molecular compound with strong water absorption and water retention. Adding an appropriate amount of cellulose to the mud film can improve the mud film's impermeability and prevent groundwater infiltration and gas loss. Cellulose can also enhance the toughness of the mud film, making it more wear-resistant and impact-resistant. Water plays the role of dissolving, diluting and transporting in the mud film material; an appropriate amount of water can ensure that bentonite, slaked lime, cellulose and water glass are fully mixed and evenly distributed on the tunnel face; at the same time, too much water will reduce the strength and stability of the mud film, while too little water may cause the mud film to fail to form or form unevenly. 735.15 parts by weight of water is just right; Water glass has strong viscosity and can react chemically with bentonite and slaked lime to produce harder compounds. At the same time, water glass can also accelerate the solidification speed of the mud film, so that it can form a stable structure in a short time. The viscosity of water glass can also enhance the sealing of the mud film and prevent the loss of gas and liquid from the mud film. The mud membrane material combines the advantages of bentonite's adhesion and expansion, slaked lime's chemical reactivity, cellulose's impermeability and toughness, water glass's curing speed and sealing, and water's appropriateness and proportion; these components cooperate and work together to form a stable, dense, highly self-stabilizing and impermeable mud membrane structure.

[0006] The present invention provides a shield pressure opening and cutting tool changing construction method using mud film material, comprising stirring slaked lime, calcium-based bentonite, sodium-based bentonite, water and cellulose according to required weight parts to obtain bentonite slurry; Add bentonite slurry and 1 / 3 of the required weight of water glass into the grouting box of the shield machine, and obtain bentonite mixed slurry by stirring; The bentonite mixed slurry prepared in the grouting box is injected into the soil bin of the shield machine to replace the slag in the soil bin of the shield machine; Inject the remaining 2 / 3 of the required weight of water glass into the soil bin of the shield machine, and obtain the composite clay mixed slurry through the rotation of the cutter head in the soil bin of the shield machine; A mud film is formed on the tunnel face by means of composite clay mixed slurry.

[0007] Through the present invention, the mud film formed by the bentonite mixed slurry at the tunnel face has strong adhesion and expansion, which can effectively support the tunnel face and prevent the collapse and instability of the stratum; by injecting the bentonite mixed slurry to replace the slag in the shield machine soil bin, the disturbance of the stratum during the shield machine excavation process can be reduced, which is conducive to maintaining the stability of the stratum; The mud film formed by the bentonite mixed slurry has good sealing properties and can effectively prevent gas from escaping from the formation, thereby controlling the amount of gas loss; by adjusting the grouting volume and grouting pressure, the thickness and sealing properties of the mud film can be further controlled, thereby achieving effective regulation of the gas pressure balance; Adding bentonite slurry and 1 / 3 of the required weight of water glass into the grouting box and stirring them can preliminarily mix the two materials to form a relatively uniform bentonite mixed slurry. This step helps to ensure that the bentonite and water glass are fully mixed before being subsequently injected into the soil bin to avoid stratification or sedimentation. After the bentonite mixed slurry is injected into the soil bin, the remaining 2 / 3 of the required weight of water glass is injected into the soil bin. At this time, the bentonite slurry and water glass can be further mixed by the rotation of the shield machine cutter head to form a composite clay mixed slurry. By first mixing some of the materials in the grouting box and then injecting the remaining materials into the soil bin, the grouting pressure and flow rate can be more flexibly controlled, which helps to avoid pressure fluctuations and uneven flow rates that may occur during the grouting process.

[0008] The method of first mixing part of the materials in the grouting box and then injecting the remaining materials into the soil bin can also adjust the grouting speed and grouting amount according to the actual construction situation to optimize the construction efficiency. For example, when the stability of the tunnel face is poor or the permeability of the formation is strong, the grouting amount and grouting speed can be appropriately increased to enhance the formation of the mud film.

[0009] As a preferred method, use a ground mortar mixing station to make bentonite slurry, with a production volume of 10m3 each time. 3 The slurry is transported to the tunnel by a battery vehicle. After entering the tunnel, it is stirred in the slurry vehicle for 3 minutes and then pumped for 5m with a mortar pump. 3 to the mortar pot.

[0010] Through the present invention, the ground mortar mixing station has a large production capacity and can produce a large amount of bentonite slurry at one time, thereby meeting the large demand for slurry in tunnel construction; the prepared bentonite slurry is transported to the tunnel by a battery vehicle, which is flexible and convenient.

[0011] During transportation, bentonite slurry may settle due to gravity, resulting in inconsistent concentration and performance between the upper and lower layers of the slurry. Re-stirring in the slurry truck can effectively avoid this situation and ensure that the slurry remains uniform throughout the entire volume.

[0012] Preferably, during the process of injecting the bentonite mixed slurry into the earth bin of the shield machine, the injection is continued to maintain the earth bin pressure stable at 0.2 to 0.3 bar higher than the set shield opening pressure, until the bentonite mixed slurry fills the gaps in the strata around the shield machine.

[0013] Through the present invention, by maintaining the soil bin pressure higher than the set shield bin opening pressure, the pressure balance during the shield machine excavation process can be ensured; this helps to reduce stress concentration and deformation in the stratum, and reduce the risk of ground subsidence; the bentonite mixed slurry has good fluidity and filling properties, and can quickly fill the stratum gaps around the shield machine to form an effective supporting layer; this helps to prevent the collapse and instability of the stratum caused by the shield machine excavation, and ensure construction safety.

[0014] Preferably, when injecting bentonite mixed slurry into the soil bin of the shield machine, the staff needs to stop injecting every 5 minutes and observe the rate of pressure drop in the bin. When the pressure gauge value continues to drop or drops rapidly, it is necessary to continue injecting bentonite mixed slurry into the bin until the pressure in the bin remains relatively stable.

[0015] Through the present invention, by regularly observing the pressure drop rate in the bin, abnormal pressure conditions can be discovered in time; when the pressure gauge value continues to drop or drops rapidly, it may mean that there are large gaps or leaks in the formation. At this time, continuing to inject bentonite mixed slurry can fill these gaps, prevent the formation from becoming unstable or collapsing, and ensure construction safety.

[0016] Preferably, during the injection of bentonite mixed slurry, the screw machine is started to discharge slag at the same time, and the pressure of the upper soil bin is controlled to be not lower than 0.4 bar below the set pressure of the shield belt pressure bin, and not higher than 0.3 bar above the set pressure of the shield belt pressure bin; when the discharged slag obviously contains bentonite mixed slurry, a slag sample is taken from the slag outlet of the screw machine on site and placed in a measuring cylinder. By observing the color of the slag sample, the sand content and the mixing experiment of adding water glass, it is determined whether the slag replacement in the bin is completed.

[0017] Through the present invention, by controlling the pressure of the upper soil bin to be not less than 0.4 bar below the shield belt pressure bin setting pressure, and not more than 0.3 bar above the shield belt pressure bin setting pressure, the pressure balance of the shield machine during the excavation process can be ensured to prevent the stratum from becoming unstable or collapsing, thereby ensuring construction safety; at the same time, the screw machine is started to discharge slag, which can ensure that the slag generated during the excavation process is discharged in time, and the slag is prevented from accumulating too much in the soil bin and affecting the excavation efficiency; by observing the color of the slag sample taken from the screw machine slag outlet, the sand content and the results of the mixing experiment of adding water glass, it can be accurately determined whether the slag replacement in the bin is completed. This helps to ensure that the bentonite mixed slurry fully fills the stratum gaps and improves the stratum stability.

[0018] Preferably, after the screw machine discharges slag, start the shield machine cutter head, rotate the cutter head at a low speed of 0.5rpm, rotate the cutter head 60°, continue to inspect the discharged slag samples, take slag samples from the screw machine outlet, and determine whether the replacement of the slag in the bin is completed by observing the slag color, sand content and adding water glass mixing test; if not completed, continue to inject bentonite mixed slurry into the soil bin while replacing the slag in the soil bin, until the slag discharged from the bin is all bentonite mixed slurry, indicating that the replacement in the bin is completed.

[0019] Through the present invention, the slag in the soil bin can be more effectively stirred and loosened by rotating the cutter disc at a low speed, so that it can be more fully mixed and replaced with the bentonite mixed slurry; this helps to improve the efficiency of slag replacement; and the discharged slag samples are continuously inspected, and by observing the color of the slag samples, the sand content, and the results of the mixing experiment of adding water glass, it can be accurately judged whether the slag replacement in the bin is completed. This ensures the accuracy and reliability of slag replacement.

[0020] As a preferred option, prepare a single-liquid grouting machine, and connect the grouting pipe to another balancing valve at the manhole position as the injection port for supplementing the water glass liquid. According to the total amount of bentonite mixed slurry injected into the soil bin, calculate the amount of water glass that needs to be supplemented to inject the remaining 2 / 3 volume, and use a secondary grouting machine to intermittently supplement the injection of water glass to form a composite clay mixed slurry; start the cutter head, the cutter head speed is 0.5rpm, and the cutter head steering direction is always maintained in the same direction. Continue to rotate the cutter head for 2h, and observe the changes in soil bin pressure and torque fluctuations during the process; if the soil bin pressure and torque are relatively stable and maintained for at least 1h, start the screw conveyor to discharge a small amount of composite clay mixed slurry, and take samples to test the properties; stop the machine for 1 hour to observe the rate of change of soil pressure, and finally form a pressure-maintaining mud film after it is relatively stable.

[0021] Through the present invention, bentonite mixed slurry is injected through a single-liquid grouting machine, and water glass is intermittently supplemented to form a composite clay mixed slurry, which can fully utilize the respective characteristics of bentonite and water glass to improve the adhesion and stability of the slurry; in the process of grouting and rotating the cutter head, by observing the pressure change in the soil bin, it can be ensured that the pressure is stable within a safe range to prevent the formation from becoming unstable or collapsing; observing the torque fluctuation can timely discover equipment failures or formation abnormalities, so as to take corresponding measures to ensure construction safety; the pressure-retaining mud film formed after stopping the machine to observe the rate of change of soil pressure can further enhance the stability of the formation and prevent the formation from deforming or settling.

[0022] As a preferred method, the pressure maintaining system is used to establish the air pressure in the soil bin and gradually replace the composite clay mixed slurry in the soil bin; the pressure maintaining system sets the shield pressure for opening the bin under pressure, starts the cutterhead, and the cutterhead speed is 0.5rpm. The cutterheads rotate in the same direction. After rotating for 15 minutes, the screw conveyor is started intermittently at a speed of 2-4rpm to discharge the composite clay mixed slurry. The screw conveyor stops discharging soil when the pressure in the soil bin is lower than the set pressure of 0.4bar for opening the bin under pressure of the shield, and starts the screw conveyor again to discharge soil when the pressure in the soil bin is restored to the set pressure for opening the bin under pressure of the shield; the soil bin liquid level is reduced to half bin in sequence, and the air pressure is replaced with the composite clay mixed slurry in the bin to provide an operating environment for the next bin opening operation; if the liquid level in the soil bin cannot be reduced to half bin, manual assisted cleaning can be used.

[0023] Through the present invention, the shield belt pressure opening pressure is set by the pressure maintaining system, and the air pressure in the soil bin can be accurately controlled, thereby optimizing the replacement process of the composite clay mixed slurry; the intermittent start-up and coordinated operation of the cutter disc and the screw conveyor can reduce unnecessary downtime and improve construction efficiency; As a preferred method, after the mud film is formed, the shield machine pressure-maintaining system is turned on, and the ball valve is opened at the same time to replace the air in the soil bin, reduce the temperature in the soil bin, and perform gas detection on the gas outlet of the ball valve to observe the pressure change in the soil bin for no less than 1 hour. At the same time, the pressure-maintaining system is turned on, the cutterhead does not rotate, and the loading and unloading of the air compressor is measured every 10 minutes; if the loading time is less than the unloading time, it proves that the mud film quality meets the requirements and the air retention of the soil bin is good; the greater the difference between the loading time and the unloading time, the better the stability of the tunnel face and the quality of the mud film. If the loading time is greater than or equal to the unloading time, it proves that the mud film has failed to be established and needs to be re-established.

[0024] Through the present invention, by observing the loading and unloading conditions of the air compressor, it can be judged whether the quality of the mud film meets the requirements; the loading time is less than the unloading time, and the larger the difference is, the better the quality of the mud film is, and the stronger the air retention of the soil bin is, thereby ensuring the safety of the shield machine during the excavation process; through timely detection and observation, the failure of mud film establishment can be discovered in time, and the mud film can be re-established, thereby avoiding unnecessary downtime and improving construction efficiency. DETAILED DESCRIPTION

[0025] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0026] Example 1 This embodiment provides a mud film material for shield tunneling with pressure opening and cutting tool changing construction, which includes the following components: Slaked lime, 282.4 parts by weight; Calcium bentonite, 141.2 parts by weight; Sodium bentonite, 141.2 parts by weight; Water, 735.15 parts by weight; cellulose, 7.35 parts by weight; and Water glass, 58.57 parts by weight.

[0027] According to the present embodiment, bentonite is a key component of the mud film material, which has strong water absorption and expansion properties and adhesion properties; the combined use of calcium-based bentonite and sodium-based bentonite can form a more compact and stable mud film structure; sodium-based bentonite has a higher water absorption rate and stronger adhesion than calcium-based bentonite, and can form a more solid mud film on the tunnel face; An appropriate amount of bentonite can ensure that the mud film has sufficient strength and stability to resist the pressure and disturbance of the formation. When the amount of calcium-based bentonite and sodium-based bentonite is 1:1, the performance of the mud film can be ensured to be optimal. Cellulose is a high molecular compound with strong water absorption and water retention. Adding an appropriate amount of cellulose to the mud film can improve the mud film's impermeability and prevent groundwater infiltration and gas loss. Cellulose can also enhance the toughness of the mud film, making it more wear-resistant and impact-resistant. Water plays the role of dissolving, diluting and transporting in the mud film material; an appropriate amount of water can ensure that bentonite, slaked lime, cellulose and water glass are fully mixed and evenly distributed on the tunnel face; at the same time, too much water will reduce the strength and stability of the mud film, while too little water may cause the mud film to fail to form or form unevenly. 735.15 parts by weight of water is just right; Water glass has strong viscosity and can react chemically with bentonite and slaked lime to produce harder compounds. At the same time, water glass can also accelerate the solidification speed of the mud film, so that it can form a stable structure in a short time. The viscosity of water glass can also enhance the sealing of the mud film and prevent the loss of gas and liquid from the mud film. The mud membrane material combines the advantages of bentonite's adhesion and expansion, slaked lime's chemical reactivity, cellulose's impermeability and toughness, water glass's curing speed and sealing, and water's appropriate amount and ratio. These components cooperate with each other and work together to form a stable, dense mud membrane structure with strong self-stability and impermeability, thereby improving the fixation of the tunnel face and ensuring the stability of the tunnel face.

[0028] This embodiment provides a shield pressure opening and cutting tool changing construction method using mud film material, comprising stirring slaked lime, calcium-based bentonite, sodium-based bentonite, water and cellulose according to required weight parts to obtain bentonite slurry; Add bentonite slurry and 1 / 3 of the required weight of water glass into the grouting box of the shield machine, and obtain bentonite mixed slurry by stirring; The bentonite mixed slurry prepared in the grouting box is injected into the soil bin of the shield machine to replace the slag in the soil bin of the shield machine; Inject the remaining 2 / 3 of the required weight of water glass into the soil bin of the shield machine, and obtain the composite clay mixed slurry through the rotation of the cutter head in the soil bin of the shield machine; A mud film is formed on the tunnel face by means of composite clay mixed slurry.

[0029] Through this embodiment, the mud film formed by the bentonite mixed slurry at the tunnel face has strong adhesion and expansion, which can effectively support the tunnel face and prevent the collapse and instability of the stratum; by injecting the bentonite mixed slurry to replace the slag in the shield machine soil bin, the disturbance of the stratum during the shield machine excavation process can be reduced, which is conducive to maintaining the stability of the stratum; The mud film formed by the bentonite mixed slurry has good sealing properties and can effectively prevent gas from escaping from the formation, thereby controlling the amount of gas loss; by adjusting the grouting volume and grouting pressure, the thickness and sealing properties of the mud film can be further controlled, thereby achieving effective regulation of the gas pressure balance; Adding bentonite slurry and 1 / 3 of the required weight of water glass into the grouting box and stirring them can preliminarily mix the two materials to form a relatively uniform bentonite mixed slurry. This step helps to ensure that the bentonite and water glass are fully mixed before being subsequently injected into the soil bin to avoid stratification or sedimentation. After the bentonite mixed slurry is injected into the soil bin, the remaining 2 / 3 of the required weight of water glass is injected into the soil bin. At this time, the bentonite slurry and water glass can be further mixed by the rotation of the shield machine cutter head to form a composite clay mixed slurry. By first mixing some of the materials in the grouting box and then injecting the remaining materials into the soil bin, the grouting pressure and flow rate can be more flexibly controlled, which helps to avoid pressure fluctuations and uneven flow rates that may occur during the grouting process.

[0030] The method of first mixing part of the materials in the grouting box and then injecting the remaining materials into the soil bin can also adjust the grouting speed and grouting amount according to the actual construction situation to optimize the construction efficiency. For example, when the stability of the tunnel face is poor or the permeability of the formation is strong, the grouting amount and grouting speed can be appropriately increased to enhance the formation of the mud film.

[0031] In this embodiment, a ground mortar mixing station is used to prepare bentonite slurry, and the amount of each production is 10m 3 The slurry is transported to the tunnel by a battery vehicle. After entering the tunnel, it is stirred in the slurry vehicle for 3 minutes and then pumped for 5m with a mortar pump. 3 to the mortar pot.

[0032] Through this embodiment, the ground mortar mixing station has a large production capacity and can produce a large amount of bentonite slurry at one time, thereby meeting the large demand for slurry in tunnel construction; the prepared bentonite slurry is transported to the tunnel by an electric vehicle, which is flexible and convenient.

[0033] During transportation, bentonite slurry may settle due to gravity, resulting in inconsistent concentration and performance between the upper and lower layers of the slurry. Re-stirring in the slurry truck can effectively avoid this situation and ensure that the slurry remains uniform throughout the entire volume.

[0034] In this embodiment, during the process of injecting bentonite mixed slurry into the soil bin of the shield machine, the injection is continued to maintain the soil bin pressure stable at 0.2 to 0.3 bar higher than the set shield opening pressure, until the bentonite mixed slurry fills the gaps in the strata around the shield machine.

[0035] Through this embodiment, by maintaining the soil bin pressure higher than the set shield opening pressure, the pressure balance during the shield machine excavation process can be ensured; this helps to reduce stress concentration and deformation in the stratum and reduce the risk of ground subsidence; the bentonite mixed slurry has good fluidity and filling properties, and can quickly fill the stratum gaps around the shield machine to form an effective support layer; this helps to prevent the collapse and instability of the stratum caused by the shield machine excavation, ensuring construction safety.

[0036] In this embodiment, when injecting bentonite mixed slurry into the soil bin of the shield machine, the staff needs to pause the injection every 5 minutes and observe the rate of pressure drop in the bin. When the pressure gauge value continues to drop or drops rapidly, it is necessary to continue injecting bentonite mixed slurry into the bin until the pressure in the bin remains relatively stable.

[0037] Through this embodiment, by regularly observing the pressure drop rate in the bin, abnormal pressure conditions can be discovered in time; when the pressure gauge value continues to drop or drops rapidly, it may mean that there are large gaps or leaks in the formation. At this time, continuing to inject bentonite mixed slurry can fill these gaps, prevent the formation from becoming unstable or collapsing, and ensure construction safety.

[0038] In this embodiment, during the injection of bentonite mixed slurry, the screw machine is started to discharge slag at the same time, and the pressure of the upper soil bin is controlled to be not lower than 0.4 bar below the set pressure of the shield belt pressure bin opening, and not higher than 0.3 bar above the set pressure of the shield belt pressure bin opening; when the discharged slag obviously contains bentonite mixed slurry, a slag sample is taken from the slag outlet of the screw machine on site and placed in a measuring cylinder. By observing the color of the slag sample, the sand content and the addition of water glass for mixing, it is determined whether the slag replacement in the bin is completed.

[0039] Through this embodiment, by controlling the pressure of the upper soil bin to be not less than 0.4 bar below the shield belt pressure opening bin setting pressure, and not more than 0.3 bar above the shield belt pressure opening bin setting pressure, the pressure balance of the shield machine during the excavation process can be ensured to prevent the stratum from becoming unstable or collapsing, thereby ensuring construction safety; at the same time, starting the screw machine to discharge slag can ensure that the slag generated during the excavation process is discharged in time to avoid excessive accumulation of slag in the soil bin and affecting the excavation efficiency; by observing the color, sand content and water glass mixing test results of the slag sample taken from the screw machine slag outlet, it can be accurately determined whether the slag replacement in the bin is completed. This helps to ensure that the bentonite mixed slurry fully fills the stratum voids and improves the stratum stability.

[0040] In this embodiment, after the screw machine discharges slag, the shield machine cutter head is started, and the cutter head is rotated at a low speed of 0.5 rpm. The cutter head is rotated 60°, and the discharged slag samples are continuously inspected. The slag samples at the slag outlet of the screw machine are taken, and the color and sand content of the slag samples are observed, and the mixing experiment of adding water glass is performed to determine whether the replacement of the slag in the bin is completed. If not completed, the bentonite mixed slurry continues to be injected into the soil bin while replacing the slag in the soil bin until the slag discharged from the bin is all bentonite mixed slurry, indicating that the replacement in the bin is completed.

[0041] Through this embodiment, the slag in the soil bin can be more effectively stirred and loosened by rotating the cutter disc at a low speed, so that it can be more fully mixed and replaced with the bentonite mixed slurry; this helps to improve the efficiency of slag replacement; and the discharged slag samples are continuously inspected, and by observing the color of the slag samples, the sand content, and the results of the mixing experiment of adding water glass, it can be accurately judged whether the slag replacement in the bin is completed. This ensures the accuracy and reliability of slag replacement.

[0042] In this embodiment, a single-liquid grouting machine is prepared, and the grouting pipe is connected to another balancing valve at the manhole position as an injection port for supplementing water glass liquid. According to the total amount of bentonite mixed slurry injected into the soil bin, the amount of water glass required to supplement the remaining 2 / 3 volume is calculated, and a secondary grouting machine is used to intermittently supplement the water glass to form a composite clay mixed slurry; the cutter disc is started, the cutter disc speed is 0.5rpm, and the cutter disc steering direction is always maintained in the same direction. The cutter disc is rotated continuously for 2 hours, and the soil bin pressure change and torque fluctuation are observed during the process; if the soil bin pressure and torque are relatively stable and maintained for not less than 1 hour, the screw conveyor can be started to discharge a small amount of composite clay mixed slurry, and samples can be taken to detect the properties; the machine is stopped for 1 hour to observe the rate of change of soil pressure, and a pressure-maintaining mud film is finally formed after it is relatively stable.

[0043] Through this embodiment, bentonite mixed slurry is injected through a single-liquid grouting machine, and water glass is intermittently supplemented to form a composite clay mixed slurry, which can fully utilize the respective characteristics of bentonite and water glass to improve the adhesion and stability of the slurry; during the grouting and rotating cutter head process, by observing the changes in soil bin pressure, it can ensure that the pressure is stable within a safe range to prevent stratum instability or collapse; observing torque fluctuations can timely discover equipment failures or stratum abnormalities, so as to take corresponding measures to ensure construction safety; the pressure-retaining mud film formed after stopping the machine to observe the rate of change of earth pressure can further enhance the stability of the stratum and prevent stratum deformation or settlement.

[0044] In this embodiment, the air pressure in the soil bin is established by the pressure maintaining system to gradually replace the composite clay mixed slurry in the soil bin; the pressure maintaining system sets the shield pressure for opening the bin under pressure, starts the cutter disc, and the cutter disc rotates at a speed of 0.5 rpm. The cutter discs rotate in the same direction. After rotating for 15 minutes, the screw conveyor is started intermittently at a speed of 2 to 4 rpm to discharge the composite clay mixed slurry. The screw conveyor is suspended when the pressure of the soil bin for discharging soil is lower than the set pressure of 0.4 bar for opening the bin under pressure of the shield, and the screw conveyor is started again to discharge soil when the pressure of the soil bin is restored to the set pressure for opening the bin under pressure of the shield; the soil bin liquid level is reduced to half bin in sequence, and the air pressure is replaced with the composite clay mixed slurry in the bin to provide an operating environment for the next bin opening operation; if the liquid level in the soil bin cannot be reduced to half bin, manual assisted cleaning can be used.

[0045] Through this embodiment, the shield belt pressure opening pressure is set by the pressure maintaining system, and the air pressure in the soil bin can be accurately controlled, thereby optimizing the replacement process of the composite clay mixed slurry; the intermittent start-up and coordinated operation of the cutter disc and the screw conveyor can reduce unnecessary downtime and improve construction efficiency; In this embodiment, after the mud film is formed, the shield machine pressure-maintaining system is turned on, and the ball valve is opened at the same time to replace the air in the soil bin, reduce the temperature in the soil bin, and perform gas detection on the gas outlet of the ball valve to observe the pressure change in the soil bin for no less than 1 hour. At the same time, the pressure-maintaining system is turned on, the cutterhead does not rotate, and the loading and unloading of the air compressor is measured every 10 minutes; if the loading time is less than the unloading time, it proves that the mud film quality meets the requirements and the air retention of the soil bin is good; the greater the difference between the loading time and the unloading time, the better the stability of the tunnel face and the quality of the mud film. If the loading time is greater than or equal to the unloading time, it proves that the mud film has failed to be established and needs to be re-established.

[0046] Through this embodiment, by observing the loading and unloading conditions of the air compressor, it can be determined whether the quality of the mud film meets the requirements; the loading time is less than the unloading time, and the larger the difference is, the better the quality of the mud film is, and the stronger the air retention of the soil bin is, thereby ensuring the safety of the shield machine during the excavation process; through timely detection and observation, the failure of mud film establishment can be discovered in time, and the mud film can be re-established, thereby avoiding unnecessary downtime and improving construction efficiency.

[0047] It is easy to understand that those skilled in the art can combine, split, reorganize, etc. the embodiments of the present application to obtain other embodiments based on one or several embodiments provided in the present application, and these embodiments do not exceed the protection scope of the present application.

[0048] The present invention and its implementation methods are described schematically above, and the description is not restrictive. The embodiments shown in the embodiments are only part of the implementation methods of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by the embodiments and designs a structure and an implementation method similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. The mud film material used in the shield pressure opening and cutting construction includes the following components: Slaked lime, 282.4 parts by weight; Calcium bentonite, 141.2 parts by weight; Sodium bentonite, 141.2 parts by weight; Water, 735.15 parts by weight; cellulose, 7.35 parts by weight; and Water glass, 58.57 parts by weight.

2. A shield tunneling pressure opening and cutting tool changing construction method using the mud film material described in claim 1, comprising: Stirring slaked lime, calcium-based bentonite, sodium-based bentonite, water and cellulose according to required weight portions to obtain bentonite slurry; Add bentonite slurry and 1 / 3 of the required weight of water glass into the grouting box of the shield machine, and obtain bentonite mixed slurry by stirring; The bentonite mixed slurry prepared in the grouting box is injected into the soil bin of the shield machine to replace the slag in the soil bin of the shield machine; Inject the remaining 2 / 3 of the required weight of water glass into the soil bin of the shield machine, and obtain the composite clay mixed slurry through the rotation of the cutter head in the soil bin of the shield machine; A mud film is formed on the tunnel face by means of composite clay mixed slurry.

3. The shield machine belt pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: Use ground mortar mixing station to make bentonite slurry, each time the production volume is 10m 3 The slurry is transported to the tunnel by a battery vehicle. After entering the tunnel, it is stirred in the slurry vehicle for 3 minutes and then pumped for 5m with a mortar pump. 3 to the mortar pot.

4. The shield machine belt pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: In the process of injecting the bentonite mixed slurry into the soil bin of the shield machine, the process is continued to maintain the soil bin pressure stable at 0.2 to 0.3 bar higher than the set shield opening pressure, until the bentonite mixed slurry fills the gaps in the strata around the shield machine.

5. The shield machine pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: When injecting bentonite mixed slurry into the soil bin of the shield machine, the staff needs to stop injecting every 5 minutes and observe the rate of pressure drop in the bin. When the pressure gauge value continues to drop or drops rapidly, it is necessary to continue injecting bentonite mixed slurry into the bin until the pressure in the bin remains relatively stable.

6. The shield machine belt pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: During the injection of bentonite mixed slurry, the screw machine is started to discharge slag at the same time, and the pressure of the upper soil bin is controlled to be no lower than 0.4 bar below the set pressure of the shield machine with pressure opening, and no higher than 0.3 bar above the set pressure of the shield machine with pressure opening. When the discharged slag obviously contains bentonite mixed slurry, a slag sample is taken from the slag outlet of the screw machine on site and placed in a measuring cylinder. By observing the color of the slag sample, the sand content and the mixing experiment of adding water glass, it is determined whether the slag replacement in the bin is completed.

7. The shield machine belt pressure opening and cutting tool changing construction method according to claim 6 is characterized in that: After the screw machine discharges slag, start the shield machine cutter head, and rotate it at a low speed of 0.5rpm. Rotate the cutter head 60°, continue to inspect the discharged slag samples, take slag samples from the screw machine outlet, and determine whether the replacement of the slag in the bin is completed by observing the slag color, sand content and adding water glass for mixing experiments. If not completed, continue to inject bentonite mixed slurry into the soil bin while replacing the slag in the soil bin, until the slag discharged from the bin is all bentonite mixed slurry, indicating that the replacement in the bin is completed.

8. The shield machine pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: Prepare a single-liquid grouting machine, and connect the grouting pipe to another balancing valve at the manhole position as the injection port for supplementing water glass liquid. According to the total amount of bentonite mixed slurry injected into the soil bin, calculate the amount of water glass that needs to be supplemented to inject the remaining 2 / 3 volume, and use a secondary grouting machine to intermittently supplement the injection of water glass to form a composite clay mixed slurry; start the cutter head, the cutter head speed is 0.5rpm, and the cutter head steering direction always keeps the same direction. Continue to rotate the cutter head for 2h, and observe the changes in soil bin pressure and torque fluctuations during the process; if the soil bin pressure and torque are relatively stable and maintained for at least 1h, start the screw conveyor to discharge a small amount of composite clay mixed slurry, and take samples to test the properties; stop the machine for 1 hour to observe the rate of change of soil pressure, and finally form a pressure-maintaining mud film after it is relatively stable.

9. The shield belt pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: The pressure-maintaining system is used to establish the air pressure in the soil bin to gradually replace the composite clay mixed slurry in the soil bin; the pressure-maintaining system sets the shield pressure for opening the bin under pressure, starts the cutterhead, and the cutterhead speed is 0.5rpm. The cutterheads rotate in the same direction. After rotating for 15 minutes, the screw conveyor is started intermittently at a speed of 2-4rpm to discharge the composite clay mixed slurry. The screw conveyor stops discharging soil when the pressure in the soil bin is lower than the set pressure of 0.4bar for opening the bin under pressure of the shield, and the soil bin pressure is restored to the set pressure for opening the bin under pressure of the shield and the screw conveyor is started again to discharge soil; the operations are carried out in sequence to reduce the liquid level in the soil bin to half the bin, complete the air pressure replacement of the composite clay mixed slurry in the bin, and provide an operating environment for the next bin opening operation; if the liquid level in the soil bin cannot be reduced to half the bin, manual assisted cleaning can be used.

10. The shield machine pressure opening and cutting tool changing construction method according to claim 2 is characterized in that: After the mud film is formed, the shield machine pressure-maintaining system is turned on, and the ball valve is opened at the same time to replace the air in the soil bin, reduce the temperature in the soil bin, and conduct gas detection on the gas outlet of the ball valve to observe the pressure change in the soil bin for no less than 1 hour. At the same time, the pressure-maintaining system is turned on, the cutterhead does not rotate, and the loading and unloading of the air compressor is measured every 10 minutes; if the loading time is less than the unloading time, it proves that the mud film quality meets the requirements and the air retention of the soil bin is good; The larger the difference between loading time and unloading time, the better the stability of the tunnel face and the quality of the mud film. If the loading time is greater than or equal to the unloading time, it proves that the mud film has failed to be established and needs to be re-established.