Shield tunneling method capable of achieving extrusion excavation

Abstract

The shield tunneling method comprises the following steps that after a screw conveyor breaks down, the pressure of a soil bin of a shield tunneling machine is adjusted, so that the pressure of the soil bin of the shield tunneling machine is larger than the pressure of a soil outlet of the screw conveyor, and the pressure difference is established; the soil body is improved through a modifier; adjusting the rotating speed of a cutter head of the shield tunneling machine to be greater than the adjusting threshold value; the tunneling speed of the shield tunneling machine is determined according to the unearthing speed of the screw conveyor; the tunneling posture of the shield tunneling machine during tunneling is controlled; synchronous grouting is conducted in the tunneling process; monitoring data during tunneling of the shield tunneling machine are obtained through earth surface monitoring, and the monitoring data are analyzed to obtain a guide parameter set. The problem that an existing screw conveyor fault processing mode is high in risk can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) technology, and more specifically to a TBM tunneling method for extruding excavated soil. Background Technology

[0002] In soft soil strata, earth pressure balance shield tunneling machines are typically used for shield tunneling operations. This means that by controlling the matching of the tunneling speed with the soil discharge speed of the screw conveyor, the pressure in the shield tunneling machine's soil chamber and the pressure in the soil are balanced, thus ensuring the safety of shield tunneling operations.

[0003] When the auger malfunctions, such as structural damage or obstruction by foreign objects, preventing excavation and halting construction, it needs to be addressed. Currently, the common practice is to reinforce the excavated soil, then remove the auger for repair or to remove the obstruction, thus resuming tunneling. However, this method has drawbacks: the quality of soil reinforcement cannot be fully guaranteed, and the limited operating space inside the tunnel makes the process time-consuming and risky.

[0004] Therefore, this application is hereby submitted. Summary of the Invention

[0005] The purpose of this invention is to provide a shield tunneling method for extruding soil by squeezing, which solves the problem of high risk in the existing screw conveyor failure handling methods.

[0006] This invention is achieved through the following technical solution: A shield tunneling method for excavating excavated soil includes the following steps: When the screw conveyor malfunctions, adjust the soil chamber pressure of the tunnel boring machine to make the soil chamber pressure of the tunnel boring machine greater than the pressure at the screw conveyor outlet in order to establish a pressure difference. Soil is improved using soil conditioners; Adjust the cutterhead speed of the tunnel boring machine to make the speed greater than the adjustment threshold; The tunneling speed of the tunnel boring machine is determined based on the soil discharge speed of the screw conveyor. Controlling the tunneling posture of the tunnel boring machine during excavation; Grouting is performed simultaneously during the tunneling process; Monitoring data during tunnel boring machine excavation is obtained through surface monitoring, and the monitoring data is analyzed to obtain a set of guidance parameters; Secondary grouting for unstable sections of the formed tunnel; Secondary grouting was performed on areas with significant surface subsidence.

[0007] Optionally, the step of adjusting the soil chamber pressure of the tunnel boring machine (TBM) to ensure that the soil chamber pressure of the TBM is greater than the pressure at the TBM's outlet after a malfunction, in order to establish a pressure differential, includes the following steps: The soil pressure and hydrostatic pressure at the center of the tunnel boring machine cutterhead are obtained; The soil chamber pressure of the tunnel boring machine in equilibrium state is calculated based on the soil pressure of the stratum and the hydrostatic pressure, and the equilibrium pressure setting value is obtained. The soil chamber pressure of the tunnel boring machine is controlled to the set balance pressure value, and tunneling is carried out. When the screw conveyor malfunctions, the pressure of the soil chamber in the tunnel boring machine is detected to obtain the pressure of the malfunctioning soil chamber. The pressure at the outlet of the screw conveyor is obtained; By comparing the pressure of the faulty soil chamber with the pressure at the screw conveyor outlet, when the pressure of the faulty soil chamber is less than the pressure at the screw conveyor outlet, the tunnel boring machine is used to advance and compress the soil to increase the real-time soil chamber pressure until the real-time soil chamber pressure is greater than the pressure at the screw conveyor outlet.

[0008] Optionally, the formula for calculating the balance pressure setpoint is: P0 = K * P1; P1=γ*h1; Wherein: P0 is the set value of the balance pressure; P1 is the sum of the soil pressure and the hydrostatic pressure; K is the lateral static earth pressure coefficient of the soil; γ is the average unit weight of the soil; h1 is the vertical distance from the center of the cutterhead of the tunnel boring machine to the ground surface.

[0009] Optionally, the formula for calculating the pressure at the screw conveyor outlet is: P2=ρgh2; Where: P2 is the pressure at the soil outlet of the screw conveyor; ρ is the density of the soil; h2 is the height from the soil outlet of the screw conveyor to the bottom of the screw conveyor.

[0010] Optionally, the amendment comprises water and a dispersible foaming agent; the slump of the amended soil is 12-16 cm.

[0011] Optionally, the adjustment threshold is 1.8 rad / min.

[0012] Optionally, determining the tunneling speed of the tunnel boring machine based on the excavation speed of the auger conveyor includes the following steps: Calculate the amount of soil excavated per 1cm of tunneling by the tunnel boring machine to obtain the amount of soil excavated per unit distance; The total amount of excavated soil is obtained based on the amount of soil removed per unit distance and the excavation distance. Based on the total amount of excavated soil and the soil removal time, the soil removal speed is obtained; The tunneling speed matched to the tunnel boring machine is calculated based on the soil excavation speed, and the tunneling speed is set to a constant speed.

[0013] Optionally, determining the tunneling speed of the tunnel boring machine based on the excavation speed of the auger conveyor includes the following steps: Calculate the amount of soil excavated per 1cm of tunneling by the tunnel boring machine to obtain the amount of soil excavated per unit distance; The total amount of excavated soil is obtained based on the amount of soil removed per unit distance and the excavation distance. Based on the total amount of excavated soil and the soil removal time, the soil removal speed is obtained; The tunneling speed matched to the tunnel boring machine is calculated based on the soil excavation speed, and the tunneling speed is set to a constant speed.

[0014] Optionally, the composition of the grout used for simultaneous grouting, by weight, is as follows: Sand and gravel: 1130 parts, fly ash: 350 parts, lime: 40 parts, cement: 50 parts, bentonite: 50 parts, admixture: 3.5 parts, and water: 350 parts.

[0015] Optionally, the formula for calculating the injection volume of the slurry is: M = k(R) 2 *π-r 2 *π)*L; Where: M is the injection volume of the grout; k is the grouting filling coefficient; R is the excavation diameter of the tunnel boring machine; r is the outer diameter of the tunnel segment; L is the excavation stroke; The injection rate of the slurry is matched with the tunneling speed of the tunnel boring machine; The injection pressure of the slurry is 4-5 bar.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides a shield tunneling method for extruding excavated soil. By fully improving the soil and establishing a pressure difference between the soil chamber of the shield machine and the soil outlet of the auger, and by establishing matching parameters such as cutterhead rotation speed and tunneling speed, the excavated soil volume is effectively controlled through synchronous grouting. Settlement data is fed back through surface monitoring to guide the improvement of tunneling parameters and subsequent secondary grouting work, thereby achieving safe shield tunneling construction. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] In the attached diagram: Figure 1 A flowchart of a shield tunneling method for extruding excavated soil provided in an embodiment of the present invention; Figure 2 This is a simplified schematic diagram of a screw conveyor provided in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0022] In the description of the embodiments of this application, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this application is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art. It is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0023] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] Please refer to Figure 1 and Figure 2 This application provides a shield tunneling method for extruding excavated soil, comprising the following steps: S1. When the screw conveyor malfunctions, adjust the soil chamber pressure of the tunnel boring machine to make the soil chamber pressure of the tunnel boring machine greater than the pressure at the screw conveyor outlet, so as to establish a pressure difference. S2. Improve the soil using soil conditioners; S3. Adjust the cutterhead speed of the tunnel boring machine to make the speed greater than the adjustment threshold; S4. Determine the tunneling speed of the tunnel boring machine based on the soil discharge speed of the screw conveyor; S5. Control the tunneling posture of the tunnel boring machine during tunneling; S6. Grouting is performed simultaneously during the tunneling process; S7. Obtain monitoring data during tunnel boring machine excavation through surface monitoring, analyze the monitoring data, and obtain a set of guidance parameters; S8. Secondary grouting for unstable parts of the formed tunnel; S9. Secondary grouting for areas with significant surface subsidence.

[0025] The shield tunneling method for extrusion soil provided in this embodiment fully improves the soil, establishes a pressure difference between the shield machine's soil chamber and the auger extrusion port, and establishes matching parameters such as cutterhead rotation speed and tunneling speed. It also effectively controls the amount of extruded soil through synchronous grouting. Settlement data is fed back through surface monitoring to guide the improvement of tunneling parameters and subsequent secondary grouting work, thereby achieving safe shield tunneling construction.

[0026] To further explain the specific method for establishing the pressure differential between the tunnel boring machine's (TBM) soil chamber pressure and the auger excavator's outlet pressure, the method involves adjusting the TBM's soil chamber pressure to ensure it exceeds the auger excavator's outlet pressure when the auger malfunctions, thereby establishing the pressure differential. This includes the following steps: S1.1 Obtain the soil pressure and hydrostatic pressure at the center of the tunnel boring machine cutterhead; S1.2 Calculate the soil pressure of the tunnel boring machine in equilibrium state based on the soil pressure and hydrostatic pressure, and obtain the equilibrium pressure set value. S1.3 Control the soil pressure of the tunnel boring machine to the set value of the balanced pressure, and then proceed with tunneling; S1.4 When the screw conveyor malfunctions, the soil chamber pressure of the tunnel boring machine is detected to obtain the pressure of the malfunctioning soil chamber; S1.5, Obtain the pressure at the outlet of the screw conveyor; S1.6. Compare the pressure of the faulty soil chamber with the pressure at the screw conveyor outlet. When the pressure of the faulty soil chamber is less than the pressure at the screw conveyor outlet, the tunnel boring machine advances forward to compress the soil to increase the real-time soil chamber pressure until the real-time soil chamber pressure is greater than the pressure at the screw conveyor outlet.

[0027] It should be noted that in order to excavate soil after the auger malfunctions, the soil pressure in the tunnel boring machine's (TBM) soil chamber must be greater than the pressure at the auger's outlet. Otherwise, soil cannot be excavated. Therefore, the TBM advances forward to compress the soil, thereby increasing the real-time pressure in the soil chamber until it exceeds the pressure at the auger's outlet, so that the malfunctioning auger can excavate soil.

[0028] To provide a detailed explanation of how the balance pressure setpoint is calculated, the formula for calculating the balance pressure setpoint is as follows: P0 = K * P1; P1=γ*h1; Wherein: P0 is the set value of the balance pressure; P1 is the sum of the soil pressure and the hydrostatic pressure; K is the lateral static earth pressure coefficient of the soil; γ is the average unit weight of the soil; h1 is the vertical distance from the center of the cutterhead of the tunnel boring machine to the ground surface.

[0029] Please refer to Figure 2 To provide a detailed explanation of the calculation method for the pressure at the auger excavator outlet, the auger is simplified as a cylinder. The formula for calculating the pressure at the auger excavator outlet is as follows: P2=ρgh2; Where: P2 is the pressure at the soil outlet of the screw conveyor; ρ is the density of the soil; h2 is the height from the soil outlet of the screw conveyor to the bottom of the screw conveyor.

[0030] To provide a specific explanation of the composition of the soil amendment, the components of the soil amendment include water and a dispersible foaming agent; the slump of the amended soil is 12-16 cm.

[0031] By modifying the water and dispersible foaming agent, the soil can be made to have higher workability and fluidity.

[0032] It should be noted that the ratio of water to dispersible foaming agent can be adjusted according to the actual soil conditions.

[0033] To provide a specific explanation of the adjustment threshold for the cutter head rotation speed, the adjustment threshold is 1.8 rad / min.

[0034] To ensure thorough mixing of the soil during cutting and achieve the desired improvement effect, the cutter head is set to high-speed rotation mode, i.e., a rotation speed of >1.8 rad / min.

[0035] It should be noted that determining the tunneling speed of the tunnel boring machine based on the excavation speed of the auger conveyor includes the following steps: S4.1 Calculate the amount of soil excavated by the tunnel boring machine per 1cm of tunneling to obtain the amount of soil excavated per unit distance; S4.2. Based on the amount of soil removed per unit distance and the excavation distance, the total amount of soil removed is obtained; S4.3. Based on the total amount of soil removed and the soil removal time, the soil removal speed is obtained; S4.4 Calculate the tunneling speed matched to the tunnel boring machine based on the excavation speed, and set the tunneling speed to be uniform.

[0036] Soil removal is achieved through the pressure difference between the soil chamber pressure of the tunnel boring machine (TBM) and the discharge port pressure of the auger conveyor. The amount of excavated material is controlled according to the tunneling progress, and the volume of excavated soil is accurately measured and calculated. The amount of excavated material in a single cycle is the same as during normal tunneling, ensuring that over-excavation or under-excavation does not occur. The tunneling speed of the TBM is determined based on the soil discharge rate to ensure that the tunneling speed matches the excavation speed, preventing over-excavation or under-excavation and avoiding excessive surface subsidence or uplift.

[0037] To provide a specific explanation of the tunneling posture control during tunnel boring machine (TBM) excavation, the tunneling posture control during TBM excavation refers to: when the TBM's excavation route is a straight section, the horizontal posture deviation of the TBM is ±15mm; when the TBM's excavation route is a curved section, the inward turning deviation of the TBM is 20-40mm; and the vertical posture deviation of the TBM is (-30)-(-20)mm.

[0038] It should be noted that the attitude of the tunnel boring machine (TBM) also needs to be adjusted in conjunction with the attitude of the tunnel segments, i.e., the monitoring data of the deviation of the tunnel axis; the attitude correction of the TBM is strictly controlled in accordance with the principles of "frequent correction" and "gradual correction".

[0039] To explain the specific composition of the grout used in the synchronous grouting, the composition of the synchronous grouting grout, by weight, is as follows: sand and gravel: 1130 parts, fly ash: 350 parts, lime: 40 parts, cement: 50 parts, bentonite: 50 parts, admixture: 3.5 parts, and water: 350 parts.

[0040] Because high earth pressure and high speed tunneling are employed, a high-density single-liquid grout, i.e., thick grout, is used in conjunction with the tunneling process. To shorten the initial setting time and improve early strength, 50 parts by weight of cement are added to the thick grout. The grouting speed must be matched with the tunneling speed to avoid under-grouting or over-grouting, which could cause surface subsidence or heave.

[0041] To provide a specific explanation of how the grout injection volume is calculated, the formula for calculating the grout injection volume is as follows: M = k(R) 2 *π-r 2 *π)*L; Wherein: M is the injection volume of the grout; k is the grouting filling coefficient (in this embodiment, k is 150-200%); R is the excavation diameter of the tunnel boring machine; r is the outer diameter of the tunnel segment; L is the tunneling stroke; the injection speed of the grout is matched with the tunneling speed of the tunnel boring machine; the injection pressure of the grout is 4-5 bar.

[0042] To provide a specific explanation of the surface monitoring method, the process of obtaining monitoring data during tunnel boring machine excavation through surface monitoring includes the following steps: S7.1. Set up monitoring points along the ground surface line, one every 2.5m; S7.2. A monitoring section shall be set up every 10m; S7.3 Obtain the monitoring data through the detection points and the monitoring sections; The monitoring frequency for monitoring points and detection sections is 4 times / day.

[0043] It should be noted that secondary grouting is performed on sections with significant changes in the attitude of the tunnel segments, unstable sections of the formed tunnel, and sections with significant surface settlement. Specifically, for sections with significant changes in the attitude of the tunnel segments or unstable sections of the formed tunnel, a double-liquid grout is injected behind the tunnel wall to stabilize them; for sections with significant surface settlement, secondary grouting is used to compensate for the loss of the strata.

[0044] In summary, the shield tunneling method for extruding excavated soil provided in this embodiment has the following beneficial effects and advantages: In the event of a screw conveyor malfunction or jamming, a method is employed that uses a dispersible foaming agent, with its mixing ratio with water determined experimentally. This simulates the mixing of workable excavated soil by the cutterhead of a tunnel boring machine (TBM). During tunneling, a pressure difference is established where the soil chamber pressure exceeds the screw conveyor outlet pressure to facilitate soil removal. This allows for the control of the TBM tunneling speed and grouting rate to match the soil removal speed. Furthermore, intensive monitoring of settlement provides feedback to guide the control of soil chamber pressure, synchronous grouting, secondary grouting, and other parameters, thereby enabling TBM tunneling construction. This method solves the problems of long processing times and high safety risks associated with handling screw conveyor malfunctions (jamming) in tunnels, especially the challenge of handling screw conveyors when ground reinforcement is unavailable, thus saving construction time.

[0045] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of shield tunneling by extrusion, characterized in that, The method comprises the following steps: adjusting the earth chamber pressure of the shield machine after the screw machine fails, so that the earth chamber pressure of the shield machine > the pressure at the screw machine's earth outlet, to establish a pressure difference; improving the soil body by using an improving agent; adjusting the cutter head rotating speed of the shield machine, so that the rotating speed > an adjustment threshold value; determining the tunneling speed of the shield machine according to the earth outlet speed of the screw machine; controlling the tunneling posture of the shield machine during tunneling; synchronously grouting during tunneling; obtaining monitoring data of the shield machine during tunneling by surface monitoring, analyzing the monitoring data, and obtaining a set of guidance parameters; secondarily grouting at unstable parts of the formed tunnel; secondarily grouting at parts with large ground subsidence.

2. A pressurized soil extrusion tunneling method according to claim 1, characterized in that, The method of adjusting the earth chamber pressure of the shield machine after the screw machine fails, so that the earth chamber pressure of the shield machine > the pressure at the screw machine's earth outlet, to establish a pressure difference, comprises the following steps: obtaining the earth pressure and the hydrostatic pressure at the center of the cutter head of the tunneling machine; calculating the earth chamber pressure of the shield machine in a balanced state according to the earth pressure and the hydrostatic pressure, to obtain a balanced pressure setting value; controlling the earth chamber pressure of the shield machine to be the balanced pressure setting value, and tunneling; detecting the earth chamber pressure of the shield machine when the screw machine fails, to obtain a failure earth chamber pressure; obtaining the pressure at the earth outlet of the screw machine; comparing the failure earth chamber pressure with the pressure at the earth outlet of the screw machine, and when the failure earth chamber pressure < the pressure at the earth outlet of the screw machine, tunneling forward by the shield machine to extrude the soil body and increase the real-time earth chamber pressure, until the real-time earth chamber pressure > the pressure at the earth outlet of the screw machine.

3. A pressurized soil ejection shield tunneling method according to claim 2, characterized by, The calculation formula of the balanced pressure setting value is: P0=K*P1; P1=γ*h1; wherein: P0 is the balanced pressure setting value; P1 is the sum of the earth pressure and the hydrostatic pressure; K is the lateral static earth pressure coefficient of the soil body; γ is the average specific gravity of the soil body; h1 is the vertical distance from the center of the cutter head of the shield machine to the ground surface.

4. A pressurized soil ejection shield tunneling method according to claim 2, characterized by, The calculation formula of the pressure at the earth outlet of the screw machine is: P2=ρgh2; wherein: P2 is the pressure at the earth outlet of the screw machine; ρ is the density of the soil body; h2 is the height from the earth outlet of the screw machine to the bottom of the screw machine.

5. The method of claim 1, wherein, The components of the improving agent include water and a dispersible foaming agent; the slump of the improved soil body is 12-16 cm.

6. The method of claim 1, wherein, The adjustment threshold value is 1.8 rad / min.

7. The extrusion dislodging tunneling method according to claim 1, characterized in that, The method of determining the tunneling speed of the shield machine according to the earth outlet speed of the screw machine comprises the following steps: calculating the earth outlet amount of the shield machine tunneling 1 cm, to obtain the earth outlet amount per unit distance; obtaining the total earth outlet amount according to the earth outlet amount per unit distance and the tunneling distance; obtaining the earth outlet speed according to the total earth outlet amount and the earth discharge time; calculating the tunneling speed of the shield machine according to the earth outlet speed, and setting the tunneling speed to be uniform.

8. The extrusion dislodging tunneling method according to claim 1, characterized in that, The control of the tunneling posture of the shield machine during tunneling refers to: when the tunneling route of the shield machine is a straight line segment, controlling the horizontal posture deviation of the shield machine to be ±15 mm; when the tunneling route of the shield machine is a curve segment, controlling the deviation of the inside of the turning of the shield machine to be 20-40 mm; controlling the vertical posture deviation of the shield machine to be (-30)-(-20) mm.

9. The extrusion dislodging tunneling method according to claim 1, characterized in that, The components of the grout for synchronous grouting are, by weight: Sand: 1130 parts, fly ash: 350 parts, lime: 40 parts, cement 50 parts, bentonite: 50 parts, admixture: 3.5 parts and water 350 parts.

10. A method according to claim 9, wherein, The calculation formula of the injection amount of the slurry is: M = k(R 2 *π-r 2 *π) * L; Wherein: M is the injection amount of the slurry; K is the grouting filling coefficient; R is the excavation diameter of the shield machine; R is the outer diameter of the segment; L is the tunneling distance; The injection speed of the slurry is matched with the tunneling speed of the shield machine; The injection pressure of the slurry is 4-5 bar.

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