System for successively updating controlled earth pressure

Abstract

To provide a system for successively updating controlled earth pressure in a shield tunneling machine, which verifies validity of the controlled earth pressure by directly measuring a relationship between muddy earth pressure in a chamber and displacement near a face, rather than setting the controlled earth pressure based on assumptions or estimates.SOLUTION: The present invention is a system S for successively updating controlled earth pressure in an earth pressure shield 1 as a shield tunneling machine. The system S for successively updating the controlled earth pressure comprises an earth removal device 17 that discharges mud from a chamber 16, a pressure gauge 22 that measures mud pressure in the chamber 16, displacement measurement means 6 (7) that measures displacement near a face FA, an analysis unit 41 that analyzes deformation characteristics of the ground based on the measured mud pressure and the measured displacement near the face, and a setting unit 42 that sets the controlled earth pressure based on the analyzed deformation characteristics.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system for successively updating the controlled earth pressure of muddy soil pressure in a chamber used in a shield tunneling machine. [Background technology]

[0002] Traditionally, managing the mud pressure inside the chamber of an earth pressure shield has been essential for maintaining the stability of the face while allowing the shield to excavate without causing deformation or subsidence of the surrounding ground, and proper management can suppress displacement of the surrounding ground.

[0003] In earth pressure shields, the controlled earth pressure of muddy soil pressure inside the chamber is set within the following range. (Passive earth pressure + water pressure) > Mud pressure in chamber (controlled earth pressure) > (Active earth pressure + water pressure) If the mud pressure in the chamber is kept within the above range, the stability of the face is theoretically ensured, but as higher mud pressure in the chamber leads to increased cutter torque and jack thrust, resulting in inefficient construction, it is desirable to set the controlled earth pressure low within the range that ensures stability of the face. Therefore, it is common to set the lower limit to a value obtained by adding α to (active earth pressure + water pressure), and the upper limit to a value that further takes into account the range of construction fluctuations in addition to the above lower limit (active earth pressure + water pressure + α), or to (static earth pressure + water pressure). Note that passive earth pressure, active earth pressure, and earth pressure at rest refer to the effective earth pressure transmitted between soil particles and do not include pore water pressure. On the other hand, muddy earth pressure in the chamber refers to the total earth pressure considering the soil particles and pore water in the chamber as a whole, and includes pore water pressure.

[0004] There are two methods for managing the mud pressure inside the chamber in conventional earth pressure shields: method 1) and method 2) shown below. 1) A method of calculating active earth pressure, passive earth pressure, static earth pressure, etc. using an earth pressure calculation formula based on the soil constants (φ, C, γ, etc.) of the target ground estimated by a prior soil survey, the groundwater level, and the overburden load, and then setting and managing upper and lower limits for the mud earth pressure inside the chamber based on these values ​​(see, for example, Patent Document 1). 2) A method of setting the controlled earth pressure based on the muddy earth pressure in the chamber measured when the shield is stopped (see, for example, Non-Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-233372 [Non-Patent Document 1] "Guidelines for Safe and Secure Construction of Shield Tunnels," Shield Tunnel Construction Technology Review Committee, December 2021, p. 19 Summary of the Invention [Problem to be solved by the invention]

[0006] ·Management method 1) Issues: Preliminary soil surveys are usually carried out by boring, and are often carried out at intervals of about 200 m along the length of the line. Therefore, if the soil conditions change between survey points, it may not be possible to calculate the appropriate control earth pressure. Furthermore, because the calculation formula for earth pressure is theoretical and based only on a simplified two-dimensional balance of forces, it does not necessarily accurately calculate the earth pressure on the shield face ground in an actual three-dimensional state.

[0007] ·Management method 2) Issues: The stopped mud pressure measured when the shield is stopped is thought to reflect the earth pressure acting on the face relatively accurately if the shield itself does not move and the cutter head does not have a face plate, but if these conditions are not maintained, the stopped mud pressure does not necessarily represent the static earth pressure of the ground or the active earth pressure plus water pressure.

[0008] In the above-mentioned management methods 1) and 2) for controlling muddy soil pressure, it is not possible to set an appropriate controlled earth pressure when the ground conditions change.

[0009] Therefore, the present invention aims to provide a system for sequentially updating the controlled earth pressure in a shield tunneling machine, which verifies the validity of the controlled earth pressure by directly measuring the relationship between the mud pressure in the chamber and the displacement near the face, rather than setting the controlled earth pressure based on assumptions or estimates. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the system for sequentially updating the controlled earth pressure in a shield tunneling machine of the present invention comprises an earth removal device that discharges mud from within a chamber, a pressure gauge that measures the mud pressure within the chamber, a displacement measurement means that measures displacement near the face, an analysis unit that analyzes the deformation characteristics of the ground based on the measured mud pressure and the measured displacement near the face, and a setting unit that sets the controlled earth pressure based on the analyzed deformation characteristics. [Effects of the Invention]

[0011] In this way, the system for successively updating the controlled earth pressure in a shield machine of the present invention comprises an earth removal device that discharges mud from within the chamber, a pressure gauge that measures the mud pressure in the chamber, a displacement measurement means that measures displacement near the tunnel face, an analysis unit that analyzes the deformation characteristics of the ground based on the measured mud pressure and the measured displacement near the tunnel face, and a setting unit that sets the controlled earth pressure based on the analyzed deformation characteristics.With this configuration, the controlled earth pressure can be set by directly measuring the relationship between the mud pressure in the chamber and the tunnel face displacement, rather than setting the controlled earth pressure based on assumptions or estimates, and the success or failure of the set controlled earth pressure can be determined by a safer and simpler method. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a cross-sectional view illustrating the internal structure of a shield tunneling machine. [Figure 2]FIG. 2 is a cross-sectional view illustrating the configuration of the detection jig and the measurement sensor. [Figure 3] An explanatory diagram of the on-board measurement method for measuring face displacement. (a) is an explanatory diagram during excavation, (b) is an explanatory diagram of inserting the detection jig, and (c) is an explanatory diagram during displacement measurement. [Figure 4] An explanatory diagram of a pre-installed face displacement measurement method. (a) is a cross-sectional view, and (b) is a longitudinal-sectional view. [Figure 5] 10 is a flowchart illustrating the procedure of a system for sequentially updating managed earth pressure. [Figure 6] FIG. 10 is a schematic diagram illustrating linear regression determination (determination method 1) using a graph showing the relationship between mud pressure and horizontal displacement while the shield machine is stopped. [Figure 7] FIG. 10 is a schematic explanatory diagram illustrating gradient determination (determination method 2) using a graph showing the relationship between mud pressure and horizontal displacement while the shield machine is stopped. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the components described in the following embodiments are merely examples and are not intended to limit the technical scope of the present invention to these alone. Note that, although the following description will be given using an earth pressure shield 1 as an example, the present invention can also be applied to other types of shield tunneling machines. Note that, although the following description includes a pressure control device, the present invention can also be implemented without the pressure control device. [Example]

[0014] (Shield tunneling machine configuration) Fig. 1 is a longitudinal side view showing an embodiment of the present invention. As shown in Fig. 1, the earth pressure shield 1 as a shield tunneling machine of this embodiment is equipped with a skin plate (shield main body cylinder) 2, a partition wall 3, a cutter head 5, a cutter rotation shaft 10, a cutter drive unit 12, a chamber 16, an earth removal device 17, a shield propulsion jack 18, a mud material supply pipe 21, a pressure gauge 22, a water pressure gauge 23, and a control unit 40 including an analysis unit 41 and a setting unit 42 arranged inside an operation room or the like.

[0015] The cutter head 5 has cutter spokes 51, a plurality of cutter bits 52, ... provided on the front surface of the cutter spokes 51, a fishtail bit 53 provided in the center of the front surface of the cutter spokes 51, and a plurality of stirring blades 54, ... provided on the back surface of the cutter spokes 51. The cutter head 5 is attached integrally to the cutter rotation shaft 10.

[0016] The cutter rotation shaft 10 is rotatably supported by a bearing 11 provided in the partition wall 3 and a bearing provided at the rear of a gear box 13 (described later). The cutter rotation shaft 10 is connected to a cutter drive unit 12. The cutter drive unit 12 has a gear box 13 installed on the rear side of the partition wall 3, a rotary drive source 14 connected to the gear box 13, and a reduction gear (disposed within the gear box 13; not shown) interposed between the output shaft of the rotary drive source 14 and the cutter rotation shaft 10.

[0017] The chamber 16 is formed by a space surrounded by the hood portion 2a of the skin plate 2, the partition wall 3, and the working face F. A screw conveyor, for example, is used as the earth removal device 17. The mud intake port of the earth removal device 17 is open and installed so as to face the chamber 16.

[0018] Furthermore, an erector 15 for assembling the segments 90 is installed in the tail portion 2b of the skin plate 2. Furthermore, multiple shield propulsion jacks 18 are installed inside the skin plate 2 at required intervals in the circumferential direction. Mud pressure is generated by the thrust of these shield propulsion jacks 18. In the case of an earth pressure shield 1, the magnitude of the jack thrust is thought to be roughly balanced with the sum of the mud pressure in the chamber and the peripheral friction force. In addition, a tail seal 19 is installed at the rear end of the skin plate 2. During shield tunneling, mud production material (also called additive material) is injected into the face and cutter chamber as appropriate depending on the soil quality of the tunneling ground.

[0019] While there is a possibility that displacement may progress after excavation is stopped, the purpose of this invention can be reliably achieved by taking the following measures during measurement setup. Specifically, between the time excavation is stopped and measurement is started, measures are taken to prevent the mud pressure from decreasing (A), measures are taken to allow measurement even if the mud pressure decreases (B), or measures are taken to allow measurement before the mud pressure decreases (C). After the excavation is stopped, the pressure in the chamber is maintained by the pressure maintaining device (for example, by continuing to inject the mud). - Before stopping excavation, increase the mud pressure above the controlled level to terminate excavation (for example, reduce the rotation speed of the screw conveyor to adjust it higher)....Method (B). Measurement setup is performed during excavation (for example, a bit-type measuring device (face vicinity property measuring device 8) is sent to the vicinity of the face before excavation is stopped)...means (C). The present invention can be realized even if the above three means are not adopted.

[0020] The earth pressure shield 1 as a shield tunneling machine of this embodiment is further equipped with displacement measurement means 6, 7 that measure the displacement of the tunnel face or the area around the tunnel face. Here, we will first use Figures 2 and 3 to explain the on-board displacement measurement means 6 that measures the displacement of the tunnel face from inside the machine, and then use Figure 4 to explain the pre-installed displacement measurement means 7, in which an instrument is installed from the ground in advance.

[0021] As shown in Figure 2, the on-board displacement measurement means 6 is composed of a rod-shaped detection jig 61 that is long enough to penetrate the bulkhead 3 and allow its tip 61a to reach the FA near the face, a hydraulic chuck 63 that grasps and releases the detection jig 61, thereby moving and releasing the detection jig 61 as the jacks 62, 62 extend and retract, a detection unit 64 that is attached integrally to the end of the detection jig 61, a guide 65 that supports the sliding movement of the detection unit 64, a displacement sensor 66 that measures the displacement of the detection jig 61 by measuring the distance from the detection unit 64, a water stop device 67 for the detection jig 61, and water stop valves 68, 68.

[0022] Therefore, when the detecting jig 61 is gripped by the hydraulic chuck 63, the detecting jig 61 moves backward when the jacks 62, 62 are extended, and moves forward when the jack 62 is retracted. When the hydraulic chuck 63 is released, the detecting jig 61 is in a free state. Therefore, in the released state (the detecting jig 61 can move freely), if the tip 61a of the detecting jig 61 is in contact with the face F or slightly penetrates the face F, the detecting jig 61 moves (in the tunnel longitudinal direction) in accordance with the displacement of the FA near the face. As will be described later, in the present invention, when the shield in the chamber 16 is stopped—for example, when the segments are assembled—a natural pressure drop causes the FA near the face to protrude slightly, and the detecting jig 61 moves in the tunnel longitudinal direction toward the wellhead.

[0023] Next, the configuration of the face vicinity property measuring device 8 that realizes the aforementioned means (C) for setting up measurements during excavation will be described using Figure 2. In the face vicinity property measuring device 8 serving as displacement measuring means in this modified example, the cylinder and rod of the jack serving as advancing and retreating means are stored inside the cutter spokes 51, although this is not shown in detail. Furthermore, if the length of the face vicinity property measuring device 8 is longer than the depth of the cutter spokes 51, it is also preferable to position the rear part of the face vicinity property measuring device 8 inside the (moving) stirring blade 54.

[0024] Next, with reference to Figure 2 and Figures 3(a)-(c), the operating procedure of the displacement measuring means 6 having the detection jig 61 and the displacement sensor 66 when the shield in this embodiment is stopped, for example, when the segments are being assembled, will be described. 1. During shield tunneling, the exploration jig 61 is retracted to the partition wall 3 position (Fig. 3(a)). 2. After the shield stops, the hydraulic chuck 63 grips the detection jig 61 and slides it until the tip 61a contacts the face F or slightly penetrates the face F (see FIG. 3(b)). The jack 62 is retracted. 3. When the tip 61a of the detection jig 61 is pressed against or penetrates the face F, the hydraulic chuck 63 is released. 4. The mud pressure inside the chamber is basically set higher than the surrounding soil and water pressure. Therefore, when the soil removal device 17 (and shield propulsion jack 18) is stopped, the mud pressure inside the chamber 16 gradually decreases while balancing with the surrounding soil and water pressure. The mud pressure inside the chamber that changes at this time is measured sequentially. 5. When the FA near the face is displaced due to the decrease in mud pressure, the displacement pushes the exploration jig 61 back into the shield (see Figure 3(c)). 6. A measuring device (detection unit 64, displacement sensor 66) is attached inside the shield of the detection jig 61. The amount of displacement is measured by the displacement sensor 66 through the detection unit 64. 7. The measurement value is sent from the displacement sensor 66 to the PC. At the same time, the pressure gauge 22 installed on the bulkhead 3 measures the mud pressure inside the chamber 16. At the same time, the water pressure is also measured by the water pressure gauge 23. 8. Using the above procedure, the relationship between the mud pressure in chamber 16 and the displacement of FA near the face is determined. 9. Once the displacement gradient of the face displacement has been determined, stop measuring displacement and mud pressure. 10. After that, the shield propulsion jack 18 is driven to increase the mud pressure in the chamber 16 to the initial state. 11. The detecting jig 61 is gripped by the hydraulic chuck 63, and the detecting jig 61 is pulled back by operating the jack 62 to retract it to the partition wall 3 position (FIG. 3(a)). The jack 62 is extended.

[0025] Of the components of the on-board displacement measurement means 6 described above, the component for measuring displacement can be replaced with pre-installed multi-stage inclinometers (or layer-by-layer settlement meters) 71-74, 75-78 that are installed in advance from the ground. That is, the pre-installed displacement measurement means 7 has a plurality of multi-stage inclinometers 71-74, 75-78 installed at a predetermined depth from the ground surface, as shown in Figure 4. The installation locations preferably include, for example, in addition to the vicinity of the face at the planned tunnel excavation position, positions directly above it and positions shifted to the left and right (and directly above them).

[0026] In other words, if multi-stage inclinometers 71-74 and layer-by-layer settlement meters are installed in advance from the ground in the cross section where the shield is scheduled to pass, and the shield excavation is temporarily stopped just before the measuring device, the mud pressure in the chamber will decrease while roughly balanced with the surrounding soil-water pressure, making it possible to measure ground displacement. These multi-stage inclinometers 71-74 are preferably buried at specified intervals in the area where the shield is scheduled to pass. In this case, it is preferable to bury them at intervals narrower than the conventional boring interval (200 (m)).

[0027] In addition, the earth pressure shield 1 further comprises a control unit 40. The control unit 40 is, for example, a general-purpose personal computer having a memory, a CPU, an SSD, etc. The control unit 40 sets the controlled earth pressure of the earth pressure shield 1 and controls the excavation. That is, during excavation, the earth pressure is changed by advancing the earth pressure shield 1 using the shield propulsion jack 18 while discharging mud using the soil removal device 17 (e.g., a screw conveyor), and at the same time, the mud pressure is measured using the pressure gauge 22. Furthermore, water pressure is measured using the water pressure gauge 23. It is of course possible to execute the functions of the analysis unit 41 and the setting unit 42, which will be described later, in a control unit (computing device; personal computer) separate from the control unit 40 that controls the excavation of the earth pressure shield 1. In this sense, the control unit can also be called a "computing unit."

[0028] The control unit 40 of this embodiment further functions as an analysis unit 41 that analyzes the deformation characteristics of the ground based on the measured mud pressure and the measured displacement of the excavation face (for example, horizontal displacement), and as a setting unit 42 that sets the controlled earth pressure based on the analyzed deformation characteristics. The control unit 40 receives input of the mud pressure value from the pressure gauge 22, the water pressure value from the water pressure gauge 23, and the input value (displacement) from the displacement sensor 66 via a communication cable 43, and is also connected to input means such as a keyboard and a mouse. Furthermore, the control unit 40 is connected to a monitor, a separate PC for excavation management, and the like as output means. The functions of the analysis unit 41 and setting unit 42 will be explained in the control flow described next.

[0029] The successive updating system S for managed earth pressure of the present invention is made up of the above-mentioned earth removal device 17, the pressure gauge 22, the displacement measuring means 6 (7), and the control unit 40 including the analysis unit 41 and the setting unit 42. In addition, the successive updating system S for managed earth pressure may be equipped with a water pressure gauge 23.

[0030] (Controlled earth pressure setting flow) Next, the flow of the system S for successively updating the managed earth pressure of this embodiment will be described with reference to Figures 5 and 6. As shown in Figure 5, the flow of the system S for successively updating the managed earth pressure is realized by executing the following steps S1 to S7.

[0031] Initial value processing (step S1) First, an initial value of the controlled earth pressure is set (Step S2) based on the initial calculated earth pressure set by a boring test or the like (Step S1). Then, the shield excavates according to this initial value of the controlled earth pressure (Step S3). In other words, in the initial stage after the shield starts excavating (before the shield is stopped), the controlled earth pressure is set based on the theoretical earth pressure calculated from the soil constants obtained from a preliminary soil survey. Alternatively, the mechanical constants of the ground obtained from the preliminary soil survey are given to the 3D-FEM model, and the controlled earth pressure is set from the relationship between the earth pressure and ground displacement.

[0032] When the shield is stopped (steps S4 to S7) Next, with the shield machine at a standstill, the earth removal device 17 (and shield propulsion jack 18) is stopped (step S4). That is, when excavation is stopped, such as when assembling the segments 90, the screw conveyor is stopped. Then, the pressure inside the chamber 16 (mud pressure) gradually decreases as it balances with the soil and water pressure acting on the face. As the pressure decreases, the mud pressure is measured using the pressure gauge 22. At the same time, the water pressure is measured using the water pressure gauge 23. Furthermore, during this pressure decrease, the displacement of the FA near the face is directly measured using the displacement measuring means 6 and 7 (step S5). The deformation characteristics are determined based on the measured mud pressure and face displacement (e.g., horizontal displacement) (step S6). That is, the mud pressure-face displacement is plotted on a graph to determine the deformation characteristics. Once the deformation characteristics are determined, the appropriateness of the controlled earth pressure value is determined (step S7). Step S7 is explained in detail below.

[0033] (Details of step S7) The amount of face displacement is measured by measuring the face displacement when the shield is stopped, and the mud pressure in the chamber is measured by simultaneously measuring the pressure. From these measurement results, it is possible to plot graphs of mud pressure in the chamber (e.g., horizontal axis) vs. horizontal face displacement (e.g., vertical axis) as shown in Figures 6 and 7 (understanding deformation characteristics: step S6).

[0034] Judgment method 1: Judgment by linear regression If the obtained deformation characteristics are approximated by a straight line, it is judged to be in the elastic region, and if they are curved, it is judged to be in the plastic region (see Figure 6). In other words, if they are approximated by a straight line, it is judged that the controlled earth pressure is being managed appropriately, and shield excavation continues (YES in step S7: proceed to step S3), and if they are approximated by a curve, the controlled earth pressure is reset (updated) (NO in step S7: proceed to step S2).

[0035] Judgment method 2: Judgment by gradient When the changing mud pressure inside the chamber is minute, it may be difficult to determine whether the grasped deformation characteristics are linear or curved. Therefore, the gradient of the grasped deformation characteristics is compared to determine whether it is similar to the gradient in the elastic region or the plastic region. The mud pressure - face horizontal displacement graph to be compared is a graph of the ground in question estimated by an FEM model set from the soil constants obtained from a prior soil survey. By comparing this with the graph obtained from the results of the prior analysis, it is determined whether the gradient is in the elastic region or the plastic region (see Figure 7), and the success or failure of the controlled earth pressure is determined.

[0036] That is, if the gradient of the deformation characteristics is close to the elastic region of the preliminary analysis, it is determined that the controlled earth pressure is appropriate and the shield excavation continues (YES in step S7: proceed to step S3), and if the gradient of the deformation characteristics is close to the plastic region of the preliminary analysis, the controlled earth pressure is reset (updated) (NO in step S7: proceed to step S2).The analysis results to be compared are not necessarily limited to the results obtained from the preliminary soil survey, and previous analysis results updated during construction may also be used for comparison.

[0037] (Correction of controlled earth pressure) Generally, the controlled earth pressure is (active earth pressure + water pressure) + α (for example, α = 10 to 30 kN / m 2 ) In other words, during shield tunneling, the mud pressure in the chamber is controlled to be slightly higher than the "active earth pressure + water pressure." For this reason, when tunneling is stopped, the mud pressure in chamber 16 slowly decreases as it balances with the soil and water pressure acting on the tunnel face.

[0038] If the analysis unit 41 determines that the value is appropriate using the linear regression determination, the gradient determination, or both methods (YES in step S7), the setting unit 42 determines that it is appropriate to maintain the current mud pressure in the chamber, and excavation continues as is. On the other hand, if the analysis unit 41 determines that the value is inappropriate (NO in step S7), the setting unit 42 determines that the current mud pressure in the chamber is lower than the appropriate value, and increases the mud pressure in the chamber by a predetermined amount (step S2). The predetermined amount of increase is 10 to 20 kN / m2 The predetermined amount to be increased varies depending on various conditions such as soil quality and the set controlled earth pressure, so it is desirable to carry out the test of the present invention again when the next cycle of excavation is completed (measurements may be taken continuously during that cycle) to check whether it is determined to be in the elastic region.

[0039] After that, it is possible to carry out the 3D-FEM model analysis described below as a separate process. However, the 3D-FEM model analysis is not essential for the present invention, and it is sufficient to reset (correct) the controlled earth pressure based on the gradient determination. (3D-FEM model analysis) Then, using the ground mechanical constants analyzed while the shield machine was stopped, a 3D-FEM analysis was performed, and the impact on the surrounding ground and adjacent structures was predicted using this 3D-FEM model analysis.

[0040] In other words, once the deformation characteristics of the target ground are clarified based on measurements of displacement and mud pressure when excavation is stopped, the mechanical constants of the ground are calculated by back-analysis of a ground model based on the in-situ boundary conditions, such as the ground structure assumed from boring surveys and the measured water pressure, etc. 3D-FEM analysis is then carried out using the mechanical constants of the ground calculated in this way.

[0041] As a result of the analysis, the presence or absence of harmful effects is determined by determining whether the amount of ground surface subsidence is below the allowable displacement. If harmful, the controlled earth pressure is changed and the analysis is redone. On the other hand, if harmless, the sequential update system S for controlled earth pressure is executed at the next position and time.

[0042] Here, mechanical constants include, for example, Young's modulus, Poisson's ratio, angle of internal friction, and cohesion. A rational simulation of behavior is possible by conducting a simulation using an FEM model based on the ground characteristics obtained from this on-site behavior. Such a rational simulation based on on-site behavior makes it possible to predict ground surface subsidence and the impact on adjacent structures in advance and more accurately, minimizing the impact on the surrounding area or setting controlled earth pressures that correspond to regulatory values ​​for ground displacement, etc.

[0043] (Analysis and Settings) On the other hand, once the deformation characteristics of the ground are understood, the yield point earth pressure can be calculated by analysis from a muddy earth pressure-displacement graph, as shown in Figure 6. That is, the analysis unit 41 of the control unit 40 determines the point where the gradient suddenly increases, regards this point as the yield point, and calculates the active earth pressure. For example, an approximate line can be calculated using the least squares method from multiple plots in the elastic region, and an approximate line can be calculated using the least squares method from multiple plots in the plastic region, and the intersection of these lines can be determined as the yield point. Alternatively, the appearance of consecutive plots that significantly deviate from the moving average can indicate that the ground has entered the transition region. If 3D-FEM model analysis is required due to the presence of nearby buildings, for example, the impact on the surrounding ground and adjacent structures can be predicted using 3D-FEM model analysis. If 3D-FEM model analysis is not required, the control earth pressure is reset based on the active earth pressure. Specifically, the controlled earth pressure in the chamber 16 during excavation must not fall below the active earth pressure plus water pressure, so it is necessary to add a factor (for example, 10 to 30 kN / m 2 ) is set as the lower limit of the controlled earth pressure. On the other hand, the upper limit of the controlled earth pressure may be calculated theoretically using C and φ calculated backward from the active earth pressure (yield point earth pressure), or may be set as a value that further takes into account the range of construction fluctuations in addition to the above lower limit. On the other hand, if a 3D-FEM model analysis is required, a 3D-FEM model analysis is performed.

[0044] In this way, the observed digital values ​​(observed values) are compared with the digital values ​​(analytical values) obtained from analysis using the model ground, and the model is constantly corrected to create a model ground that is consistent with changes in the ground as the shield face advances (the so-called "digital twin").

[0045] (effect) Next, the effects of the system S for successively updating the controlled earth pressure according to this embodiment will be listed and explained.

[0046] (1) As described above, the controlled earth pressure sequential updating system S of this embodiment is a controlled earth pressure sequential updating system S for an earth pressure shield 1 as a shield tunneling machine, and includes an earth removal device 17 that discharges mud from the chamber 16, a pressure gauge 22 that measures the mud pressure in the chamber 16, displacement measuring means 6, 7 that measure the displacement of the FA near the face, an analysis unit 41 that analyzes the deformation characteristics of the ground based on the measured mud pressure and the measured displacement of the face, and a setting unit 42 that sets the controlled earth pressure based on the analyzed deformation characteristics. Because of this configuration, the controlled earth pressure sequential updating system S can set (or update) the controlled earth pressure by directly measuring the relationship between the mud pressure in the chamber and the displacement of the face, rather than setting the controlled earth pressure based on assumptions or estimates.

[0047] (2) Furthermore, when the shield is stopped, as the mud pressure in the chamber 16 changes, the analysis unit 41 analyzes the deformation characteristics of the ground, and the setting unit 42 sets the controlled earth pressure based on the analyzed deformation characteristics of the ground. By utilizing the pressure drop when the shield is stopped in this way, it is possible to analyze the deformation characteristics and set (or revise) the controlled earth pressure by using the drop in mud pressure in the chamber caused by trying to balance it with the surrounding soil-water pressure, without conducting a decompression test or the like (without actively decompressing).

[0048] Specifically, when the shield is stopped, for example, during segment assembly, and the soil removal device 17 is stopped and the mud pressure in the chamber 16 decreases, the analysis unit 41 analyzes the deformation characteristics of the ground, and the setting unit 42 sets the controlled earth pressure based on the analyzed deformation characteristics of the ground, making the work extremely simple and not affecting the shield excavation process.In addition, the risk of inducing loosening of the surrounding ground is reduced, allowing shield excavation to continue safely.

[0049] (3) Furthermore, the analysis unit 41 calculates the gradient of the graph of mud earth pressure and face displacement, and the setting unit 42 updates the controlled earth pressure by at least one of linear regression judgment and gradient judgment. With this configuration, it is only necessary to judge whether the controlled earth pressure is correct or not using measurement values ​​at several points, so the controlled earth pressure can be set (or revised or updated) safely and reliably without changing the pressure up to the yield point earth pressure such as active earth pressure.

[0050] (4) The displacement measuring means 6 also includes an exploration tool 61 that penetrates the partition 3 to reach the FA near the face, and a displacement sensor 66 that measures the displacement of the exploration tool 61 on the minehead side of the partition 3. Therefore, the exploration tool 61 and the displacement sensor 66 can directly measure the displacement of the FA near the face from inside the machine. Therefore, the displacement sensor 66 itself is less likely to get dirty or break down. Note that the displacement measuring means 6 may be configured so that it does not penetrate the partition 3, by installing the exploration tool, displacement sensor, etc. in the chamber 16 in front of the partition.

[0051] (5) Furthermore, as the displacement measurement means 7, a multi-stage inclinometer and / or layer-specific settlement meter 71-78 is installed in advance in the ground where excavation is planned, so that in addition to the FA near the face, displacement over a wide area can be directly measured up to the measurement point near the ground surface.

[0052] (6) In addition, the analysis unit 41 estimates the mechanical constants of the ground by inverse analysis based on the analyzed deformation characteristics of the ground, updates the FEM model using the estimated mechanical constants of the ground, and uses the updated FEM model to predict the impact on the surrounding ground and / or structures. Therefore, although not completely in real time, by updating the FEM model at intervals that are close to real time and much shorter than conventional methods, the characteristics of the ground can be made much closer to the actual characteristics. As a result, predictions and impact assessments using the FEM model can be achieved with extremely high accuracy.

[0053] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not deviate from the gist of the present invention are included in the present invention.

[0054] For example, in the embodiment, an example has been described in which the detecting jig 61 as displacement measuring means penetrates the partition wall 3 and reaches the FA near the face, but this is not limited to this, and the detecting jig 61 does not have to penetrate the partition wall 3, and may be placed on the cutter spokes (using the near-face property measuring device 8) as long as it is configured to be able to move forward and backward within the chamber 16. Also, in the embodiment, the water pressure gauge 23 is attached to the top of the skin plate 2, but this is not limited to this, and it may be attached to another part of the skin plate 2, the cutter head 5, etc.

[0055] In addition, in the examples, the gradient of the graph of the mud pressure in the chamber versus the displacement amount, which is the actual measured value, was compared with the gradient estimated (predicted) from the results of the preliminary FEM analysis, but this is not limited to this.In addition to the analysis results, the comparison can also be made with the gradient (actual measured value) of the graph of the mud pressure in the chamber versus the displacement amount at each segment assembly (the previous or the time before that). [Explanation of symbols]

[0056] 1: Earth pressure shield 2: Skin plate 2a: Hood part 2b: Tail section 3: Bulkhead 5: Cutter head 6: Displacement measurement means 7: Displacement measurement means 8: Face vicinity property measuring device (displacement measuring means) 10: Cutter rotation axis 11: Bearing 12: Cutter drive unit 13: Gearbox 14: Rotation drive source 15: Erector 16: Chamber 17:Earth removal equipment 17A: Pressure control device (including soil removal device) 18: Shield propulsion jack 19: Tail seal 21:Soil supply piping 22: Pressure gauge 23: Water pressure gauge 40: Control section 41:Analysis Department 42: Setting section 43: Communication cable 51: Cutter Spoke 52: Cutter bit 53: Fishtail bit 54: Mixing blade 61: Inspection jig 61a: Tip 62: Jack 63: Hydraulic chuck 64: Detection unit 65: Guide 66: Displacement sensor 67: Water stop device 68: Valve 71-78: Multi-stage inclinometer (or layer-by-layer settlement meter) 90: Segment S: Sequential update system for controlled earth pressure F: Face FA: Near the face

Claims

1. A system for sequentially updating controlled earth pressure in a shield tunneling machine, a soil discharge device that discharges mud from the chamber; a pressure gauge for measuring the mud pressure in the chamber; a displacement measuring means for measuring a displacement in the vicinity of the tunnel face; an analysis unit that analyzes the deformation characteristics of the ground based on the measured mud pressure and the measured displacement near the tunnel face; a setting unit that sets the controlled earth pressure based on the analyzed deformation characteristics; A system for sequentially updating controlled earth pressure.

2. 2. A system for sequentially updating controlled earth pressure as described in claim 1, wherein when the shield is stopped, as the mud soil pressure in the chamber changes, the analysis unit analyzes the deformation characteristics of the ground, and the setting unit sets the controlled earth pressure based on the analyzed deformation characteristics of the ground.

3. 3. A sequential update system for controlled earth pressure as described in claim 2, wherein the analysis unit analyzes the mud earth pressure and a displacement graph near the face, and the setting unit sets the controlled earth pressure by determining at least one of a linear regression judgment of the graph or a gradient judgment.

4. The displacement measurement means includes an exploration jig that reaches the vicinity of the face, and a displacement sensor that measures the displacement of the exploration jig. A sequential update system for managed earth pressure as described in any one of claims 1 to 3.

5. A sequential update system for controlled earth pressure as described in any one of claims 1 to 3, wherein a multi-stage inclinometer and / or a layer-by-layer settlement meter are pre-installed in the ground where excavation is planned as the displacement measurement means.

6. The analysis unit Based on the analyzed deformation characteristics of the ground, the mechanical constants of the ground are estimated by inverse analysis, and the FEM model is updated using the mechanical constants of the ground.

5. The system for successively updating controlled earth pressure according to claim 4, wherein the updated FEM model is used to predict the effects on the surrounding ground and / or structures.

7. The analysis unit Based on the analyzed deformation characteristics of the ground, the mechanical constants of the ground are estimated by inverse analysis, and the FEM model is updated using the mechanical constants of the ground.

6. The system for successively updating controlled earth pressure according to claim 5, wherein the updated FEM model is used to predict the effects on the surrounding ground and / or structures.

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