Water-rich stratum shield muck improvement device and method

Abstract

The invention discloses a water-rich stratum shield muck improvement method. The method comprises the following steps that S1, the integrity of a ball valve of a man bin partition plate of a shield tunneling machine is determined and checked; s2, the length of a pipeline, needing to be connected to the erector platform, of the muck modifier injection device is determined; s3, calculating an actually measured muck permeability coefficient HC; s4, calculating the maximum permeability coefficient HCmax of the muck; s5, comparing the HC with the HCmax, if HCgt; if HCmax, connecting the muck modifier injection device; s6, calculating the injection amount of the modifier; and S7, modifying agent injection work is carried out. According to the water-rich stratum shield muck improvement method, muck flow plasticity can be improved, the problem that no footage exists in tunneling of a shield tunneling machine in the water-rich stratum is solved, and the gushing phenomenon of a screw conveyor is reduced.

Description

Technical Field

[0001] The invention relates to the field of underground tunnel shield construction, in particular to a device and method for improving shield slag in water-rich strata. Background Art

[0002] With the rapid development of China's economy, major cities have ushered in large-scale expansion. In order to solve traffic congestion and meet the needs of large-capacity and rapid transportation, major cities in China are accelerating the development and utilization of underground space, especially the construction of various underground tunnels. At present, a considerable part of underground tunnels are constructed by shield method. When the shield machine is excavated in the water-rich sand layer and the stratum with large groundwater, the phenomenon of screw machine gushing often occurs. Most of them will use foam or bentonite slurry improvement methods to increase the plasticity of the slag flow and reduce the screw machine gushing. However, if the groundwater continues to flow into the soil bin, foam and bentonite slurry cannot play an effective improvement role, and it needs to be configured in advance, which takes a long time and has a high cost. In addition, injecting foam or bentonite when the shield machine has no advance will cause a sudden increase in the pressure of the shield soil bin, which may cause or increase the screw machine gushing phenomenon. Therefore, how to solve the problem of shield machine excavating without advance in water-rich strata and reduce the gushing phenomenon is a key factor in process control in shield construction. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a device and method for improving shield slag in water-rich strata, so as to improve the shield soil bin slag, increase the slag flow plasticity, improve the problem of no advance when the shield machine is excavating in water-rich strata, and reduce the gushing phenomenon of the screw machine.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for improving shield slag in water-rich strata, comprising the following steps: S1: Determine and check the integrity of the ball valve of the shield machine's manhole partition; S2: Determine the length of the pipeline that needs to be connected from the soil conditioner injection device to the assembly machine platform; S3: Calculate the measured soil permeability coefficient HC based on the soil sample at the screw conveyor; S4: Calculate the maximum permeability coefficient HC of the soil based on the mechanical parameters of the shield machine and the formation parameters max ; S5: Comparison of the measured soil permeability coefficient HC and the maximum soil permeability coefficient HC max , if HC>HC max , then connect the soil conditioner injection device; if HC≤HCmax, no operation is required; S6: Calculate the injection amount of the improver; S7: Perform the work of injecting the improver.

[0005] In S2, the slag improver injection device includes a shell, the lower end of the shell is connected to a gas inlet valve, and the other end of the gas inlet valve is connected to a reserved pipeline on the assembly machine platform through a high-pressure grouting pipe; the upper end of the shell is connected to a one-way valve, and the one-way valve is connected to a ball valve on the manhole partition through a high-pressure grouting pipe; one side of the shell is connected to the improver injection valve.

[0006] A plurality of stirring fans are fixed in the shell, and the stirring fans include a bracket, which is fixed to the shell and has a cone-shaped bottom; fan blades are arranged on the upper part of the bracket.

[0007] In S3, the measured soil permeability coefficient HC is calculated, which specifically includes: S3.1: Take part of the screw machine slag as the test sample; S3.2: Establishing Darcy's law, unit time t The amount of water flowing through the test sample is: (1); Where: dVe is the volume flowing per unit time, α is the cross-sectional area of ​​the glass tube carrying the test sample, and dh is the head loss; S3.3: According to Darcy's law, the amount of seepage out of the test sample in the differential time is: (2); Where: Vo is the seepage velocity; HC is the measured soil permeability coefficient, Δ h For any time t The head difference acting on the two sections, L is the test sample length, A is the cross-sectional area of ​​the test sample; S3.4: According to the principle of water flow continuity, we can get: (3); Combining the above formulas, we can deduce: (4); Where: Δ h1 is the initial head difference ， Δ h2 To end the head difference.

[0008] In S4, calculate the maximum permeability coefficient HC of the slag max , including: S4.1: Take any section of the shield soil bin and screw machine, and assume that the groundwater flow rate passing through the two sections per unit time is S 1 and S 2. Assume that the distance from the front end of the soil bin to the screw conveyor in the horizontal direction is x , h At this time, the groundwater head of the shield machine is high. h rightx Differentiating it, we can get the water flow in the shield soil bin: S 1 and water flow in the spiral machine S 2:

[0009] in: dh is the head loss of groundwater through the interface, dx is the horizontal distance of the cross section, A 1 is the cross-sectional area of ​​the shield soil bin, A 2 is the cross-sectional area of ​​the screw machine, is the angle between the screw machine and the horizontal line; S4.2: Assume that the groundwater level at the tunnel face is H 1. The water level at the outlet of the screw conveyor is H 2, we can deduce: (3); in: L 1 is the length of the shield soil bin, L 2 is the length of the screw machine; Combining the above formulas, the water pressure in the shield soil bin can be deduced as: (4); The water pressure in the screw machine is: (5); S4.3: According to the law of conservation of flow, we know S 1= S 2=S. In addition, the height of the junction between the shield soil bin and the screw machine is the same, and the water pressure at the outlet of the screw machine can be deduced. H 2 and the groundwater pressure at the tunnel face is H 1The relationship is: (6); Then the maximum permeability coefficient of soil is HC max It can be expressed as: (7).

[0010] In S5, a soil conditioner injection device is connected, specifically including: S5.1: Clean dust and foreign matter from each interface; S5.2: Close all valves; S5.3: Connect the high-pressure grouting pipe at the head of the soil conditioner injection device to the ball valve of the manhole partition of the shield machine; S5.4: Connect the high-pressure grouting pipe at the bottom of the soil conditioner injection device to the valve of the reserved pipeline on the assembly machine platform.

[0011] In S6, the amount of the modifier injected is calculated, specifically including: S6.1: Calculate the moisture content of the shield soil bin: Take part of the screw machine soil as a test sample and calculate the moisture content of the soil using the drying method. k , then the water content in the shield chamber soil can be calculated as: (1); in: A 1 is the cross-sectional area of ​​the shield soil bin, L 1 is the length of the soil bin, M is the water content in the soil of the shield bin; S6.2: After calculating the water content in the shield soil bin, calculate the amount of modifier injection. The ratio of the modifier injection amount to the water content in the shield soil bin is 2:400, 1.5:400 and 1:400 respectively. The amount of modifier injection is: (2); Wherein: PAM stands for polyacrylamide, CMC stands for sodium carboxymethyl cellulose, SAP stands for sodium polyacrylate, and C stands for the injection amount of the improver.

[0012] In S7, the improver injection work is carried out, which specifically includes: S7.1: Open the improver injection valve; S7.2: Inject the improver into the shell in an appropriate amount according to the actual situation; S7.3: Close the improver injection valve; S7.4: Open the valve of the reserved pipeline on the assembly machine platform; S7.5: Open the gas inlet valve; S7.6: After all the improver in the shell has been blown into the shield machine cabin partition, close all ball valves; S7.7: When more improver needs to be injected, repeat S7.1- S7.6 and inject in batches.

[0013] The present invention provides a device and method for improving shield slag in water-rich strata, which has the following technical effects: 1) By adopting the slag improver injection device, the slag in the shield soil bin is improved, the slag flow plasticity is increased, the problem of no advance of the shield machine in water-rich strata is improved, and the gushing phenomenon of the screw machine is reduced.

[0014] 2) Calculate the measured soil permeability coefficient HC through soil samples, and calculate the maximum soil permeability coefficient HC through the mechanical parameters of the shield machine and the formation parameters. max ; By comparing the measured soil permeability coefficient HC and the maximum soil permeability coefficient HC max , thereby controlling the precise injection amount of the soil conditioner injection device to ensure that it meets the actual project requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a flow chart of the present invention.

[0016] Figure 2 It is a schematic structural diagram of the slag improver injection device of the present invention.

[0017] Figure 3 It is a cross-sectional view of the slag improver injection device of the present invention.

[0018] Figure 4 Schematic diagram of calculating the measured soil permeability coefficient HC in the present invention (B represents the glass tube, and Y represents the test sample).

[0019] Figure 5 The maximum permeability coefficient HC is calculated in the present invention. max Schematic diagram of (Z represents the tunnel face).

[0020] Figure 6 The present invention is a flow chart of connecting the slag improver injection device.

[0021] Figure 7 The figure is a flow chart of the improver injection work in the present invention.

[0022] In the figure: shell 1, stirring fan 2, improver injection valve 3, gas inlet valve 4, one-way valve 5, high-pressure grouting pipe 6, bracket 21, fan blade 22, pipe section 31, first ball valve 32, bell-mouth thread 41, second ball valve 42. DETAILED DESCRIPTION

[0023] A slag improver injection device comprises a shell 1, a stirring fan 2, an improver injection valve 3, a gas inlet valve 4, a one-way valve 5, and a high-pressure grouting pipe 6.

[0024] The shell 1 is made of steel and can withstand high-pressure gas. The lower part of the shell 1 is flat and connected to the gas inlet valve 4. The gas inlet valve 4 is composed of a bell-mouth thread 41 and a second ball valve 42. The gas inlet valve 4 is connected to the high-pressure grouting pipe 6, which is connected to the reserved pipeline on the assembly machine platform. The upper part of the shell 1 is conical to facilitate gas circulation. A one-way valve 5 is connected to the upper part to prevent the backflow of gas and improver. The one-way valve 5 is connected to the high-pressure grouting pipe 6, which is connected to the ball valve on the man-bin partition.

[0025] like Figure 2-3As shown, the shell 1 is hollow inside, and a plurality of stirring fans 2 are arranged in the shell 1. Gas is blown in through the gas inlet valve 4 at the bottom. The improver in the shell 1 flows with the gas and drives the stirring fan 2 to rotate, so that the gas and the improver are evenly mixed. The stirring fan 2 is composed of a bracket 21 and a fan blade 22. The bracket 21 is connected to the shell 1 to fix the stirring fan 2 in the shell 1. The bottom of the bracket 21 is a cone streamline, which can reduce air resistance and reduce the influence on gas flow.

[0026] like Figure 2-3 As shown, there is an opening on the side of the shell 1 near the bottom, and the opening is connected to the improver injection valve 3. The improver injection valve 3 is composed of a pipe section 31 and a first ball valve 32. One end of the pipe section 31 is welded to the opening of the shell 1, and the other end is threaded. The pipe section 31 is threadedly connected to the first ball valve 32. The improver injection valve 3 is the injection port of the improver. When injecting, the ball valve is opened first, and then the first ball valve 32 is closed after the improver is injected.

[0027] A method for improving water-rich stratum muck soil, comprising the following steps: S1: Determine and check the integrity of the shield machine's manhole partition ball valve, including but not limited to checking its appearance integrity, mechanical integrity and air tightness, to ensure that it can be well connected with the slag conditioner injection device to ensure construction safety.

[0028] S2: Determine the length of the pipeline that needs to be connected to the slag conditioner injection device to the assembly machine platform, and prepare for the subsequent connection of the slag conditioner injection device.

[0029] S3: Calculate the measured soil permeability coefficient HC based on the soil sample at the screw conveyor.

[0030] S4: Calculate the maximum permeability coefficient HC of the soil based on the mechanical parameters of the shield machine and the formation parameters max .

[0031] S5: Compare HC and HCmax, if HC>HC max , then connect the soil conditioner injection device.

[0032] S6: Calculate the injection amount of the improver.

[0033] S7: Perform the work of injecting the improver.

[0034] like Figure 4 As shown, in S3, the measured soil permeability coefficient HC is calculated, which specifically includes: S3.1: Based on the Shenzhen Airport to Daya Bay intercity rail transit project (hereinafter referred to as Shenzhen-Daya Bay intercity rail transit) under construction, some screw machine slag was taken as test samples. The test samples were 30 cm long and 10 cm in diameter. S3.2: By establishing the instantaneous Darcy law, the measured soil permeability coefficient HC is derived, unit time t The amount of water flowing through the test sample is: (1); Among them: dVe is the volume flowing per unit time, that is, the flow rate, a is the area of ​​the flow section, and dh is the head loss. When calculating, the diameter of the glass tube is 0.5 cm, so the cross-sectional area is 0.196 cm 2 ; S3.3: According to Darcy's law, the amount of seepage out of the test sample in the differential time is: (2); Where: Vo is the seepage velocity; HC is the measured soil permeability coefficient, Δ h For any time t The head difference acting on the two sections, L is the test sample length, A is the cross-sectional area of ​​the test sample; S3.4: According to the principle of water flow continuity, we can get: (3); Combining the above formulas, we can deduce: (4); Where: Δ h1 is the initial head difference ， Δ h2 To end the head difference; The initial head difference Δ h1 The water head difference is 20cm, and the water head difference Δ is ended after 2 minutes. h2 is 15.4 cm, then the measured soil permeability coefficient is HC = 0.39 × 10 -1 cm / s.

[0035] like Figure 5 As shown in S4, the maximum permeability coefficient HC of the slag is calculated max , including: S4.1: The diameter of the deep-to-city intercity excavation is 9.14m. The excavation depth is 63.5m, the soil yard length is 1.55m, the screw machine length is 13.5m, and the screw machine inclination is 28.4°. Take any section of the shield soil bin and screw machine, and assume that the groundwater flow rate passing through the two sections per unit time is S 1 and S 2. Assume that the distance from the front end of the soil bin to the screw conveyor in the horizontal direction is x , h At this time, the groundwater head of the shield machine is high. h right xDifferentiating it, we can get the water flow in the shield soil bin: S 1 and water flow in the spiral machine S 2:

[0036] in: dh is the head loss of groundwater through the interface, dx is the horizontal distance of the cross section, A 1 is the cross-sectional area of ​​the shield soil bin, A 2 is the cross-sectional area of ​​the screw machine, is the angle between the screw machine and the horizontal line; S4.2: Assume that the groundwater level at the tunnel face is H 1. The water level at the outlet of the screw conveyor is H 2, we can deduce: (3); in: L 1 is the length of the shield soil bin, L 2 is the length of the screw machine; Combining the above formulas, the water pressure in the shield soil bin can be deduced as: (4); The water pressure in the screw machine is: (5); S4.3: According to the law of conservation of flow, we know S 1= S 2=S, groundwater flow; In addition, the height of the junction between the shield soil bin and the screw machine is the same, and the water pressure at the screw machine outlet can be deduced H 2 and the groundwater pressure at the tunnel face is H 1The relationship is: (6); Then the maximum permeability coefficient of soil is HC max It can be expressed as: (7); The spiral machine gate can withstand S=5cm 3 / s flow rate, the maximum soil permeability HC is calculated max The coefficient is 1.36×10 -3 cm / s, due to HC>HC max , need to carry out improver injection.

[0037] like Figure 2-3 , Figure 6 As shown, in S5, a slag improver injection device is connected, specifically including: S5.1: Clean the dust and foreign matter from each interface, including the manhole partition ball valve, the second ball valve 42 of the gas inlet valve 4 and the first ball valve 32 of the improver injection valve 3; S5.2: Close all valves, including the valves of the reserved pipelines on the assembly platform, the second ball valve 42 of the gas inlet valve 4, and the first ball valve 32 of the improver injection valve 3; S5.3: Connect the high-pressure grouting pipe 6 at the head of the improver injection device to the shield machine cabin partition ball valve, and make sure the connection is tight to prevent gas and improver from overflowing; S5.4: Connect the high-pressure grouting pipe 6 at the bottom of the improver injection device to the valve of the reserved pipeline on the assembly machine platform. After completing the above steps, calculate the amount of improver.

[0038] In S6, the amount of the modifier injected is calculated, specifically including: S6.1: Calculate the moisture content of the shield soil bin: Take part of the screw machine soil as a test sample and calculate the moisture content of the soil using the drying method. k , when calculating k If the water content in the shield chamber soil is 32.9%, the water content in the shield chamber soil can be calculated as: (1); in: A 1 is the cross-sectional area of ​​the shield soil bin, L 1 is the length of the soil bin. According to the above shield machine parameters, the water content in the shield soil bin can be calculated. M 33090kg; S6.2: After calculating the water content in the shield soil bin, calculate the amount of modifier injection. The modifier is a high molecular polymer, including polyacrylamide (PAM), sodium carboxymethyl cellulose (CMC) and sodium polyacrylate (SAP). The ratio of its injection amount to the water content in the shield soil bin is 2:400, 1.5:400 and 1:400 respectively. The amount of modifier injection is: (2); When the improver is SPA, the improver injection amount is 82.7 kg. After calculating the improver injection amount, the improver injection work is carried out.

[0039] like Figure 7 As shown, in S7, the work of injecting the improver is performed, which specifically includes: S7.1: Open the first ball valve 32 on the improver injection valve 3; S7.2: Inject sodium polyacrylate into the housing 1 in an appropriate amount according to the actual situation; S7.3: Close the improver injection valve 32; S7.4: Open the valve of the reserved pipeline on the assembly machine platform; S7.5: Open the second ball valve 42 on the gas inlet valve 4; S7.6: After all the high molecular polymer in the shell is blown into the shield machine manhole partition, close all ball valves, including the ball valve on the manhole partition, the second ball valve 42 on the gas inlet valve 4 and the ball valve of the reserved pipeline of the assembling machine.

[0040] S7.7: When more improver needs to be injected, repeat S7.1- S7.6 and inject in batches.

Claims

1. A method for improving shield slag in water-rich strata, comprising the following steps: S1: Determine and check the integrity of the ball valve of the shield machine's manhole partition; S2: Determine the length of the pipeline that needs to be connected from the soil conditioner injection device to the assembly machine platform; S3: Calculate the measured soil permeability coefficient HC based on the soil sample at the screw conveyor; S4: Calculate the maximum permeability coefficient HC of the soil based on the mechanical parameters of the shield machine and the formation parameters max ; S5: Comparison of the measured soil permeability coefficient HC and the maximum soil permeability coefficient HC max , if HC>HC max , then connect the soil conditioner injection device; if HC≤HCmax, no operation is required; S6: Calculate the injection amount of the improver; S7: Perform the work of injecting the improver.

2. A method for improving shield slag in water-rich strata according to claim 1, characterized in that: In S2, the slag improver injection device comprises a shell (1), the lower end of the shell (1) is connected to a gas inlet valve (4), and the other end of the gas inlet valve (4) is connected to a reserved pipeline on the assembly machine platform through a high-pressure grouting pipe (6); the upper end of the shell (1) is connected to a one-way valve (5), and the one-way valve (5) is connected to a ball valve on the manhole partition through the high-pressure grouting pipe (6); and one side of the shell (1) is connected to the improver injection valve (3).

3. A method for improving shield slag in water-rich strata according to claim 2, characterized in that: A plurality of stirring fans (2) are fixed in the housing (1), and the stirring fans (2) comprise a bracket (21). The bracket (21) is fixed to the housing (1) and has a cone-shaped bottom. Fan blades (22) are provided on the upper part of the bracket (21).

4. The method for improving shield slag in water-rich strata according to claim 1, characterized in that: In S3, the measured soil permeability coefficient HC is calculated, which specifically includes: S3.1: Take part of the screw machine slag as the test sample; S3.2: Establishing Darcy's law, unit time t The amount of water flowing through the test sample is: （1）； Where: dVe is the volume flowing per unit time, α is the cross-sectional area of ​​the glass tube carrying the test sample, dh is the head loss; S3.3: According to Darcy's law, the amount of seepage out of the test sample in the differential time is: （2）； Where: Vo is the seepage velocity; HC is the measured soil permeability coefficient, Δ h For any time t The head difference acting on the two sections, L is the test sample length, A is the cross-sectional area of ​​the test sample; S3.4: According to the principle of water flow continuity, we can get: （3）； Combining the above formulas, we can deduce: （4）； Where: Δ h1 is the initial head difference ， Δ h2 To end the head difference.

5. The method for improving shield slag in water-rich strata according to claim 1, characterized in that: In S4, the maximum permeability coefficient HC of the soil is calculated max , specifically including: S4.1: Take any section of the shield soil bin and screw machine, and assume that the groundwater flow rate passing through the two sections per unit time is S 1 and S 2. Assume that the distance from the front end of the soil bin to the screw conveyor in the horizontal direction is x , h At this time, the groundwater head of the shield machine is high. h right x Differentiating it, we can get the water flow in the shield soil bin: S 1 and water flow in the spiral machine S 2: in: dh is the head loss of groundwater through the interface, dx is the horizontal distance of the cross section, A 1 is the cross-sectional area of ​​the shield soil bin, A 2 is the cross-sectional area of ​​the screw machine, is the angle between the screw machine and the horizontal line; S4.2: Assume that the groundwater level at the tunnel face is H 1. The water level at the outlet of the screw conveyor is H 2, we can deduce: （3）； in: L 1 is the length of the shield soil bin, L 2 is the length of the screw machine; Combining the above formulas, the water pressure in the shield soil bin can be deduced as: （4）； The water pressure in the screw machine is: （5）； S4.3: According to the law of conservation of flow, we know S 1= S 2=S, S is the groundwater flow rate; in addition, the height of the shield soil bin and the screw machine is the same, and the water pressure at the screw machine outlet can be deduced H 2 and the groundwater pressure at the tunnel face is H 1The relationship is: （6）； The maximum permeability coefficient of soil is HC max It can be expressed as: （7）。 6. The method for improving shield slag in water-rich strata according to claim 2, characterized in that: In S5, a soil conditioner injection device is connected, specifically including: S5.1: Clean dust and foreign matter from each interface; S5.2: Close all valves; S5.3: Connect the high-pressure grouting pipe (6) at the head of the soil conditioner injection device to the ball valve of the manhole partition of the shield machine; S5.4: Connect the high-pressure grouting pipe (6) at the bottom of the soil conditioner injection device to the valve of the reserved pipeline on the assembly machine platform.

7. The method for improving shield slag in water-rich strata according to claim 1, characterized in that: In S6, the amount of the modifier injected is calculated, specifically including: S6.1: Calculate the moisture content of the shield soil bin: Take part of the screw machine soil as a test sample and calculate the moisture content of the soil using the drying method. k , then the water content in the shield chamber soil can be calculated as: （1）； in: A 1 is the cross-sectional area of ​​the shield soil bin, L 1 is the length of the soil bin, M is the water content in the soil of the shield bin; S6.2: After calculating the water content in the shield soil bin, calculate the amount of modifier injection. The ratio of the modifier injection amount to the water content in the shield soil bin is 2:400, 1.5:400 and 1:400 respectively. The amount of modifier injection is: （2）； Wherein: PAM stands for polyacrylamide, CMC stands for sodium carboxymethyl cellulose, SAP stands for sodium polyacrylate, and C stands for the injection amount of the improver.

8. The method for improving shield slag in water-rich strata according to claim 2, characterized in that: In S7, the improver injection work is carried out, which specifically includes: S7.1: Open the improver injection valve (3); S7.2: injecting a modifying agent into the housing (1) in an appropriate amount according to the actual situation; S7.3: Close the improver injection valve (3); S7.4: Open the valve of the reserved pipeline on the assembly machine platform; S7.5: Open the gas inlet valve (4); S7.6: After all the improver in the shell has been blown into the shield machine cabin partition, close all ball valves; S7.7: When more improver needs to be injected, repeat S7.1- S7.6 and inject in batches.

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