Controlled earth pressure setting system

Abstract

To provide a pressure control device that can accurately and easily control the pressure inside a chamber required for carrying out a decompression test.SOLUTION: A pressure control device 8 (8A) of this embodiment is a pressure control device 8 that controls the pressure inside a chamber 16 of a shield tunneling machine, and comprises a volume change mechanism that changes the volume inside a chamber by moving at least a portion of it outside the chamber 16. The volume change mechanism comprises a recess 81 formed in a partition wall 3, a jack 82 installed inside the recess 81, and a support plate 83 attached to a front side of the jack 82. The support plate 83 is designed to be retracted into the inside of the machine from a reference position that forms the same plane as the partition wall 3 by driving the jack 82 to extend or retract.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure control device in a chamber used in a shield tunneling machine.

Background Art

[0002] Conventionally, the management of the earth pressure in the chamber in an earth pressure balance shield is essential for tunneling the shield while maintaining the face stability and preventing deformation and settlement of the surrounding ground. By performing appropriate management, the displacement of the surrounding ground can be suppressed.

[0003] In an earth pressure balance shield, the management earth pressure of the earth pressure in the chamber is set within the following range. (Passive earth pressure + water pressure)> Chamber earth pressure (management earth pressure) > (Active earth pressure + water pressure)

[0004] If the earth pressure in the chamber is maintained within the above range, the face stability is theoretically ensured. However, if the earth pressure in the chamber increases, it will cause an increase in cutter torque and jack thrust, resulting in inefficiency in construction. Therefore, it is desirable to set the management earth pressure low within the range where the face stability is ensured. Therefore, generally, for the lower limit value, a value obtained by adding α to (active earth pressure + water pressure) is used, and for the upper limit value, a value obtained by further considering the construction variation range to the lower limit value (active earth pressure + water pressure + α), or (at-rest earth pressure + water pressure) is set.

[0005] Here, the passive earth pressure, active earth pressure, and at-rest earth pressure refer to the effective earth pressure transmitted between soil particles and do not include pore water pressure. On the other hand, the 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.

[0006] The conventional methods for managing the earth pressure in the chamber in an earth pressure balance shield include the following methods 1) and 2). 1) Based on the soil constants (φ, C, γ, etc.) of the target ground estimated by prior soil surveys, the groundwater level, and the overburden load, use the calculation formula for earth pressure to calculate the active earth pressure, passive earth pressure, static earth pressure, etc. Based on these values, set and manage the upper and lower limit values of the chamber earth pressure (for example, see Patent Document 1). 2) A method of setting the control earth pressure based on the earth pressure in the chamber at the time of shield stop measured when the shield stops (for example, see Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] ·Problems with Management Method 1): Prior soil surveys are usually carried out by boring, but the frequency is often about every 200 m of the route length. Therefore, when the soil conditions change between the survey points, it may not be possible to calculate the appropriate control earth pressure. In addition, since the earth pressure calculation formula itself is a theoretical one based only on the two-dimensional simplified force balance, it is not always possible to accurately calculate the earth pressure of the actual three-dimensional shield face ground.

[0009] ·Problems with Management Method 2): The earth pressure in the chamber at the time of shield stop measured when the shield stops is considered to accurately reflect the earth pressure acting on the face when the shield itself does not move and there is no panel on the cutter head. However, when these conditions are not maintained, the earth pressure at the time of stop does not necessarily represent the static earth pressure of the ground or the active earth pressure plus the water pressure.

[0010] Therefore, the inventors have developed a control earth pressure setting system for a shield tunneling machine that sets the control earth pressure by directly measuring the relationship between the earth pressure inside the chamber and the displacement near the face, rather than setting the control earth pressure by assumption or estimation. In this control earth pressure setting system, in order to obtain the deformation characteristics based on the pressure change inside the chamber of the target ground, it is necessary to conduct a pressure reduction test to reduce the earth pressure inside the chamber.

[0011] Conventionally, in order to change the pressure inside the chamber, a method of adjusting the rotation of the screw conveyor to control the earth discharge amount has been used. However, in the control of the earth discharge amount by the screw conveyor, there is a problem that it is difficult to accurately control the pressure inside the chamber. That is, since the pressure inside the chamber during shield stop decreases significantly even with a small amount of earth discharge, in order to accurately control the pressure, a minute amount of earth discharge control is required.

[0012] Therefore, an object of the present invention is to provide a pressure control device that can accurately and easily control the pressure inside the chamber required for conducting the pressure reduction test.

Means for Solving the Problems

[0013] In order to achieve the above object, the pressure control device of the present invention is a pressure control device that controls the pressure inside the chamber of a shield tunneling machine, and is provided with a volume change mechanism that changes the volume inside the chamber by moving at least a part of it outside the chamber.

[0014] Further, the control earth pressure setting system in the shield tunneling machine of the present invention includes a pressure gauge that measures the earth pressure inside the chamber, the above-described pressure control device, a displacement measuring means that measures the displacement of the face, an analysis unit that analyzes the deformation characteristics of the ground based on the measured earth pressure and the measured displacement of the face, and a setting unit that sets the control earth pressure based on the analyzed deformation characteristics.

Effects of the Invention

[0015] Thus, the pressure control device of the present invention is a pressure control device for controlling the pressure inside the chamber of a shield tunneling machine, and is provided with a volume change mechanism that changes the volume inside the chamber by moving at least a part thereof outside the chamber. With such a configuration, it is possible to accurately and easily control the pressure inside the chamber required for conducting a decompression test.

[0016] In addition, the management earth pressure setting system in the shield tunneling machine of the present invention includes a pressure gauge for measuring the earth pressure inside the chamber, the above-described pressure control device, displacement measuring means for measuring the displacement of the face, an analysis unit for analyzing the deformation characteristics of the ground based on the measured earth pressure and the measured displacement of the face, and a setting unit for setting the management earth pressure based on the analyzed deformation characteristics. With such a configuration, it is possible to set the management earth pressure not by assumption or estimation, but by directly measuring the relationship between the earth pressure inside the chamber and the face displacement.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the components described in the following examples are illustrative, and are not intended to limit the technical scope of the present invention thereto. In the following, the earth pressure shield 1 will be described as an example, but the present invention can also be applied to other types of shield tunneling machines.

Example

[0019] (Configuration of Shield Tunneling Machine) FIG. 1 is a longitudinal side view showing an embodiment of the present invention. The earth pressure shield 1 as the shield tunneling machine of the present embodiment includes, as shown in FIG. 1, a skin plate (shield main body cylinder) 2, a bulkhead 3, a cutter head 5, a cutter rotating shaft 10, a cutter drive unit 12, a chamber 16, an earth discharging device 17, a shield propulsion jack 18, a working soil 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 the operation room and the like.

[0020] 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 fish tail bit 53 provided at 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 integrally attached to the cutter rotating shaft 10.

[0021] The cutter rotation shaft 10 is rotatably supported by a bearing 11 provided on the partition wall 3 and a bearing provided at the rear part 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 includes a gear box 13 installed on the back side of the partition wall 3, a rotary drive source 14 connected to the gear box 13, and a reduction gear (arranged in the gear box 13; not shown) interposed between the output shaft of the rotary drive source 14 and the cutter rotation shaft 10.

[0022] The chamber 16 is formed in a space surrounded by the hood portion 2a of the skin plate 2, the partition wall 3, and the face F. As the earth discharging device 17, for example, a screw conveyor is used. The earth intake port of the earth discharging device 17 is opened and installed so as to face the chamber 16. In this embodiment, although it is not essential for the earth discharging device 17 to be used as a pressure control device (earth pressure changing means), it can also be used as a pressure control device.

[0023] Furthermore, an erector 15 for assembling the segment 90 is installed on the tail portion 2b of the skin plate 2. Furthermore, a plurality of shield propulsion jacks 18 are installed inside the skin plate 2 at required intervals in the circumferential direction. In addition, a tail seal 19 is provided at the rear end portion of the skin plate 2.

[0024] And the earth pressure shield 1 as a shield tunneling machine of this embodiment further includes displacement measuring means 6 and 7 for measuring the displacement of the face or the periphery of the face. Here, first, the in-machine measuring type displacement measuring means 6 for measuring the displacement of the face from inside the machine will be described with reference to FIGS. 2 and 3, and then the pre-installed type displacement measuring means 7 for installing instruments in advance from the ground will be described with reference to FIG. 4.

[0025] The in-machine measurement type displacement measurement means 6, as shown in FIG. 2, includes a rod-shaped exploration jig 61 having a length sufficient to penetrate the partition wall 3 and reach the face F with its tip 61a, a hydraulic chuck 63 that grips / releases the exploration jig 61 and moves / releases the exploration jig 61 as the jacks 62, 62 expand and contract, a detection unit 64 integrally attached to the end of the exploration jig 61, a guide 65 that supports the sliding movement of the detection unit 64, a displacement sensor 66 that measures the displacement amount of the exploration jig 61 by measuring the distance from the detection unit 64, a water stop device 67 for the exploration jig 61, and water stop valves 68, 68.

[0026] Therefore, when the exploration jig 61 is gripped by the hydraulic chuck 63, the exploration jig 61 retreats when the jacks 62, 62 extend, and the exploration jig 61 advances when the jacks 62 contract. And when the hydraulic chuck 63 is released, the exploration jig 61 is in a free state. Therefore, in the open state (the exploration jig 61 can move freely), if the tip 61a of the exploration jig 61 is in contact with the face F, the exploration jig 61 moves (in the longitudinal direction of the tunnel) in accordance with the displacement of the face F. As will be described later, in the present invention, since the face F slightly protrudes by reducing the earth pressure in the chamber 16, the exploration jig 61 moves in the shaft direction in the longitudinal direction of the tunnel.

[0027] Next, with reference to FIGS. 2 and 3(a)-(c), the operation procedure of the displacement measurement means 6 having the exploration jig 61 and the displacement sensor 66 in the decompression test of this embodiment will be described. 1. During shield tunneling, the exploration jig 61 is in a state of being retracted to the position of the partition wall 3 (FIG. 3(a)). 2. After the shield stops, grip the exploration jig 61 with the hydraulic chuck 63 and slide it to the position where the tip 61a contacts the face F surface (see FIG. 3(b)). The jacks 62 are retracted. 3. When the tip 61a of the exploration jig 61 is pressed against the face F, release the hydraulic chuck 63. 4. Operate the soil discharge means at a very low speed and gradually reduce the earth pressure in the chamber 16. 5. When the face F is displaced with the reduction of pressure, the displacement causes the exploration tool 61 to be pushed into the shield (see Fig. 3(c)). 6. A measuring device (detection unit 64, displacement sensor 66) is attached to the exploration tool 61 within the shield. The amount of displacement is measured by the displacement sensor 66 through the detection unit 64. 7. The measured value is sent from the displacement sensor 66 to the PC. At the same time, the earth pressure within the chamber 16 is measured by the pressure gauge 22 provided on the partition wall 3. 8. The relationship between the earth pressure within the chamber 16 and the displacement amount of the face F is obtained by the above procedure. 9. When all or part of the transition region (including the yield point) in the face displacement becomes clear, the pressure reduction test is stopped. 10. For example, the soil discharging means is reversed to return the soil and increase the earth pressure within the chamber 16 to the initial state. 11. The exploration tool 61 is gripped by the hydraulic chuck 63, pulled back by operating the jack 62, and the exploration tool 61 is retracted to the position of the partition wall 3 (Fig. 3(a)). The jack 62 is extended.

[0028] Among the configurations of the in - machine measurement type displacement measurement means 6 described above, for the configuration that measures displacement, it can also be replaced with pre - installed multi - stage inclinometers (or layer - by - layer settlement gauges) 71 - 74, 75 - 78 installed in advance from the ground. That is, as shown in Fig. 4, for the pre - installed displacement measurement means 7, a plurality of multi - stage inclinometers 71 - 74, 75 - 78 are installed at a predetermined depth position from the ground surface. As the installation positions, for example, in addition to the vicinity of the face at the planned tunnel excavation position, it is preferable to include the positions directly above and shifted left and right (and directly above) of it.

[0029] That is, by pre - installing multi - stage inclinometers 71 - 74, layer - by - layer settlement gauges, etc. from the ground in advance within the cross - section where the shield is planned to pass, temporarily stopping the shield excavation immediately before the measuring device, and conducting the pressure reduction test, it becomes possible to measure the displacement of the ground. These multi - stage inclinometers 71 - 74 are preferably buried at a predetermined interval at the location where the shield is planned to pass. In this case, it is preferable to bury them at an interval narrower than the conventional boring interval (200 (m)).

[0030] (Pressure control device of the embodiment) Next, with reference to FIGS. 5, 6(a), and 6(b), the configuration and operation of the pressure control device 8 of the embodiment will be described. As shown in FIGS. 5, 6(a), and 6(b), the pressure control device 8 is provided with a volume change mechanism that changes (increases) the volume inside the chamber 16 by moving a part of it outside the chamber 16. The volume change mechanism includes a recess 81 formed in the partition wall 3, a jack 82 installed in the recess 81, and a pressure support plate 83 attached to the front side of the jack 82. The pressure support plate 83 is configured to be drawn inward of the machine from a reference position that forms the same plane as the partition wall 3 by driving the jack 82 to expand and contract.

[0031] Specifically, the recess 81 is a bottomed cylindrical case that has the jack 82 and the pressure support plate 83 inside. The jack 82 is composed of a cylinder part 82a and a rod part 82b. The cylinder part 82a of the jack 82 is fixed to the back side of the recess 81, and the rod part 82b is configured to move forward and backward (reciprocate) on the front side of the recess 81. A pressure support plate 83 is attached to the front side (face side) of the rod part 82b. The pressure support plate 83 is configured to form the same plane as the partition wall 3 when the jack 82 is extended.

[0032] During shield tunneling, as shown in FIG. 6(a), the pressure support plate 83 of the pressure control device 8 is in a position where it forms the same plane as the partition wall 3. On the other hand, when a pressure reduction test is performed after the shield stops, as shown in FIG. 6(b), the pressure support plate 83 is moved backward by contracting the jack 82. As a result of this operation, the soil inside the chamber 16 is taken into the recess (case) 81 of the pressure control device 8. As a result, the pressure inside the chamber 16 decreases.

[0033] In this way, since the amount of soil taken in is controlled by the expansion and contraction of the jack 82, it is possible to control a very small amount. The amount of soil taken in can be increased or decreased by expanding or contracting the cross-sectional area of the pressure control device 8. Also, the amount of soil taken in can be adjusted by increasing or decreasing the number of pressure control devices 8. After that, when the decompression test is completed, by extending the jack 82 of the pressure control device 8, the support plate 83 is pushed back to the initial position (reference position), and the pressure in the chamber 16 is restored.

[0034] (Pressure control device of modified example) Next, with reference to FIGS. 7(a) and 7(b), the configuration and operation of the pressure control device 8A of the modified example will be described. As shown in FIGS. 7(a) and 7(b), the pressure control device 8A includes a volume change mechanism that changes (increases) the volume inside the chamber 16 by moving a part of it outside the chamber 16. The volume change mechanism includes a stirring blade 84 protruding into the chamber 16 from the partition wall 3, and a jack 85 attached to the back side of the stirring blade 84. The stirring blade 84 is configured to be retracted inward of the machine from a reference position protruding a predetermined amount from the partition wall 3 by driving the jack 85 to expand and contract.

[0035] Specifically, the stirring blade 84 is formed in a cylindrical shape and penetrates through an opening 3a provided in the partition wall 3 so as to protrude into the chamber 16 by a predetermined amount. A jack 85 is attached to the rear end side (shaft mouth side) of the stirring blade 84. The jack 85 is composed of a cylinder part 85a and a rod part 85b. The cylinder part 85a is fixed to the skin plate 2 side via a bracket 86, and the stirring blade 84 is attached to the rod part 85b. Therefore, by contracting the jack 85, the stirring blade 84 is retracted inward of the machine by a predetermined amount, so the stirring blade 84 can be referred to as a slide stirring blade 84.

[0036] During shield tunneling, as shown in Fig. 7(a), the (slide) stirring blade 84 penetrates the partition wall 3 and protrudes into the chamber 16 (reference position). On the other hand, when a pressure reduction test is carried out after the shield stops, as shown in Fig. 7(b), by operating the jack 85 to pull out the (slide) stirring blade 84 from the chamber 16, the substantial empty volume in the chamber 16 is increased, and the pressure in the chamber 16 is decreased. In this way, by operating the jack 85, a minute change in the empty volume can be controlled, enabling accurate pressure management.

[0037] The change amount of the empty volume in the chamber 16 can be increased or decreased by expanding or contracting the cross-sectional area of the (slide) stirring blade 84 of the pressure control device 8A. Also, the change amount of the empty volume can be adjusted by increasing or decreasing the number of the pressure control devices 8A. After the pressure reduction test is completed, the pressure in the chamber 16 can be restored by pushing the (slide) stirring blade 84 back to its original position.

[0038] (Configuration of the control system) In addition, the earth pressure shield 1 further includes a control unit 40. The control unit 40 is, for example, a general-purpose personal computer having a memory, a CPU, an SSD, etc. In the control unit 40, the management earth pressure of the earth pressure shield 1 is set to control tunneling. That is, during tunneling, while the earth pressure shield 1 is advanced by the shield propulsion jack 18, the earth pressure is changed by discharging the soil by the soil discharging device 17 (screw conveyor), and at the same time, the earth pressure is measured by the pressure gauge 22. Further, the water pressure is measured by the water pressure gauge 23. It should be noted that the functions of the analysis unit 41 and the setting unit 42 described later can of course be executed by a control unit (arithmetic unit; personal computer) separate from the control unit 40 that controls the tunneling of the earth pressure shield 1. In this sense, the control unit can also be referred to as an "arithmetic unit".

[0039] Then, the control unit 40 of this embodiment further has a function as an analysis unit 41 that analyzes the deformation characteristics of the ground based on the measured earth pressure and the measured displacement of the face (for example, horizontal displacement), and a function as a setting unit 42 that sets the control earth pressure based on the analyzed deformation characteristics. In addition, the control unit 40 receives the earth 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 the communication cable 43. Further, input means such as a keyboard and a mouse are connected to the control unit 40. Furthermore, a monitor and another PC for tunneling management are connected to the control unit 40 as output means. The functions of the analysis unit 41 and the setting unit 42 will be described in the control flow described below.

[0040] Then, the pressure gauge 22 described above, the pressure control device 8 (8A) described above, the displacement measurement means 6 (7), and the control unit 40 including the analysis unit 41 and the setting unit 42 constitute the control earth pressure setting system S of the present invention. In addition, a water pressure gauge 23 is provided.

[0041] (Function) Next, with reference to FIGS. 8 to 10, the flow of the control earth pressure setting system S of this embodiment will be described. As shown in FIG. 8, the flow of the control earth pressure setting system S is realized by executing the following steps S1 to S14.

[0042] · Processing of initial values (step S1) First, based on the initial calculated earth pressure set by a boring test or the like (step S1), the initial value of the control earth pressure is set (step S2). Then, according to this initial value of the control earth pressure, the shield is advanced (step S3). That is, at the initial stage when the shield starts tunneling (before the decompression test is carried out), the control earth pressure is set based on the theoretical earth pressure calculated from the soil constants obtained by the preliminary soil investigation. Alternatively, the mechanical constants of the ground obtained by the preliminary soil investigation are given to the 3D-FEM model, and the control earth pressure is set from the relationship between the earth pressure and the ground displacement.

[0043] · Decompression test (steps S4 to S8) Next, with the shield tunneling machine stopped, the earth pressure in the chamber is reduced (step S4). That is, during tunneling stops such as when assembling the segment 90, the pressure control device 8 (8A) pulls the pressure plate 83 (or the stirring blade 84) slightly inward into the machine to control with high precision while gradually discharging the earth in the chamber 16 to reduce the pressure. During the pressure reduction, the earth pressure is measured by the pressure gauge 22. At the same time, the water pressure is measured by the water pressure gauge 23. Further, during the pressure reduction, the displacement of the face F is directly measured by the displacement measuring means 6 and 7 (step S5). Based on the measured earth pressure and the displacement of the face (for example, the horizontal displacement), the deformation characteristics are grasped (step S6). That is, the earth pressure-face displacement is plotted on a graph to obtain the deformation characteristics. Once the deformation characteristics are grasped, the mechanical constants of the ground are analyzed by inverse analysis (step S7) (step S8).

[0044] · 3D-FEM model analysis (steps S9 to S12) Then, using the mechanical constants of the ground analyzed by the pressure reduction test, 3D-FEM analysis as shown in Fig. 10 is executed (step S9). And by this 3D-FEM model analysis, the influence on the surrounding ground and adjacent structures is predicted (step S10).

[0045] That is, once the deformation characteristics of the target ground are clarified by the pressure reduction test, the mechanical constants of the ground are calculated by inverse analysis (step S7) for the ground model based on the in-situ boundary conditions such as the ground composition assumed from boring surveys and the measured water pressure (step S8). Using the mechanical constants of the ground calculated in this way, 3D-FEM analysis as shown in Fig. 10 is executed (step S9).

[0046] As a result of the analysis, it is determined whether there is any adverse effect by judging whether the ground surface settlement amount and the like are equal to or less than the allowable displacement amount (step S11). If it is harmful (\"Yes\" in step S11), the controlled earth pressure is changed (step S12), and the analysis is performed again (steps S9 to S11). On the other hand, if it is harmless (\"No\" in step S11), the process returns to step S2, and the controlled earth pressure setting system S is executed at the next position and time.

[0047] Here, the mechanical constants are, for example, Young's modulus, Poisson's ratio, internal friction angle, cohesion, and the like. By adopting a FEM model based on the ground characteristics obtained from this in-situ behavior and performing a simulation, a reasonable behavior simulation becomes possible. Through a reasonable simulation based on the in-situ behavior as described above, it becomes possible to predict in advance and more accurately the ground surface settlement and the influence on adjacent structures, etc., and to minimize the influence on the surroundings or to set a controlled earth pressure corresponding to the regulated values of ground displacement and the like.

[0048] ·Analysis and setting (steps S13 to S14) On the other hand, if the deformation characteristics of the ground are grasped, the yield point earth pressure can be obtained by analysis from the earth pressure-displacement graph as shown in FIG. 9 (step S13). That is, the analysis unit 41 of the control unit 40 obtains the point where the gradient suddenly becomes large, regards this point as the yield point, and obtains the active earth pressure. For example, an approximate straight line can be obtained by the least squares method from a plurality of plots in the elastic region, an approximate straight line can be obtained by the least squares method from a plurality of plots in the plastic region, and the intersection of these can be set as the yield point. Alternatively, it can be estimated that the transition region has been entered when plots that deviate significantly from the moving average appear continuously. And when 3D-FEM model analysis is necessary due to reasons such as the presence of a building in the vicinity ( "required" in step S14), the influence on the surrounding ground and adjacent structures is predicted by 3D-FEM analysis (step S10). When 3D-FEM model analysis is not required ( "not required" in step S14), the control earth pressure is reset based on the active earth pressure (step S2). Specifically, since it is necessary to ensure that the control earth pressure in the chamber 16 during tunneling does not fall below the active earth pressure plus the water pressure, the obtained active earth pressure + water pressure plus α (0 to 20 kN / m 2 2) is used as the lower limit value of the control earth pressure. On the other hand, the upper limit value of the control earth pressure may be calculated theoretically using C and φ calculated inversely from the active earth pressure (yield point earth pressure), or may be a value obtained by further considering the construction variation range in addition to the above lower limit value. On the other hand, when 3D-FEM model analysis is necessary ( "required" in step S14), 3D-FEM model analysis is executed (step S9).

[0049] In this way, the observed digital numerical values (observed values) and the digital numerical values (analytical values) obtained from the analysis by the model ground are collated, and while constantly performing model correction, a model ground that matches the change in the ground accompanying the progress of the shield face is realized (so-called "digital twin").

[0050] (Effect) Next, the effects exerted by the pressure control device 8(8A) and the control earth pressure setting system S of the present embodiment will be described while enumerating them.

[0051] (1) As described above, the pressure control device 8(8A) of this embodiment is a pressure control device 8 that controls the pressure inside the chamber 16 of the shield tunneling machine, and is provided with a volume change mechanism that changes the volume inside the chamber by moving at least a part to the outside of the chamber 16. By providing such a volume change mechanism, it is possible to accurately and easily control the pressure inside the chamber 16 required for performing the decompression test.

[0052] (2) Further, the volume change mechanism includes a recess 81 formed in the partition wall 3, a jack 82 installed in the recess 81, and a support pressure plate 83 attached to the front side of the jack 82. The support pressure plate 83 is configured to be drawn into the machine interior from a reference position that forms the same plane as the partition wall 3 by driving the jack 82 to expand and contract. For this reason, the volume inside the chamber 16 increases by an amount corresponding to the amount of retraction of the support pressure plate 83, and the pressure can be changed. That is, when the support pressure plate 83 is drawn into the recess 81, soil enters the recess 81, so the pressure inside the chamber 16 decreases by that amount.

[0053] (3) Furthermore, the volume change mechanism includes an agitation blade 84 protruding into the chamber 16 from the partition wall 3, and a jack 85 attached to the back side of the agitation blade 84. The agitation blade 84 is configured to be drawn into the machine interior from a reference position protruding a predetermined amount from the partition wall 3 by driving the jack 85 to expand and contract. For this reason, the volume inside the chamber 16 increases by an amount corresponding to the amount of retraction of the agitation blade 84, and the pressure can be changed. That is, when the agitation blade 84 is drawn into the machine interior, the volume inside the chamber 16 increases by a volume corresponding to the amount of retraction of the agitation blade 84, and the pressure decreases.

[0054] (4) As described above, the management earth pressure setting system S of this embodiment is a management earth pressure setting system S in the earth pressure balance shield 1 as a shield tunneling machine, including a pressure gauge 22 for measuring the earth pressure in the chamber 16, pressure control devices 8 and 8A for changing the earth pressure in the chamber 16, displacement measuring means 6 and 7 for measuring the displacement of the face F, an analysis unit 41 for analyzing the deformation characteristics of the ground based on the measured earth pressure and the measured displacement of the face, and a setting unit 42 for setting the management earth pressure based on the analyzed deformation characteristics. With such a configuration, for the management earth pressure setting system S, the management earth pressure can be set not by setting based on assumptions or estimations, but by directly measuring the relationship between the earth pressure in the chamber and the displacement of the face.

[0055] (5) Also, when the shield tunneling machine stops, the pressure control devices 8 and 8A draw a predetermined amount of soil inside the machine, thereby reducing the earth pressure in the chamber 16. As a result, the active earth pressure can be obtained from the deformation of the ground by the analysis unit 41. Therefore, when the shield tunneling machine stops tunneling - for example, during segment assembly - the inside of the chamber 16 is slightly depressurized to slightly displace the face F toward the chamber 16 side, and the yield point can be directly obtained by analyzing the yield point from the transition region in the relationship graph between the earth pressure and the face displacement amount.

[0056] (6) In addition, based on the analyzed deformation characteristics of the ground, the analysis unit 41 estimates the mechanical constants of the ground by inverse analysis, updates the FEM model using the estimated mechanical constants of the ground, and predicts the influence on the surrounding ground and / or structures using the updated FEM model. Therefore, although it is not completely real-time, by updating the FEM model at intervals much finer than before, approaching real-time updating, the characteristics of the ground can be made much closer to the actual characteristics. For this reason, prediction and impact evaluation by the FEM model can be realized with extremely high accuracy.

[0057] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are included in the present invention.

[0058] For example, in the embodiment, the example where the exploration jig 61 penetrates the partition wall 3 and reaches the face F has been described. However, it is not limited to this. As long as the exploration jig 61 is configured to be movable forward and backward within the chamber 16, it does not have to penetrate the partition wall 3. Further, in the embodiment, the pressure gauge 23 is attached to the partition wall 3. However, it is not limited to this, and it may be attached to, for example, the skin plate 2 or the cutter head 5.

[0059] Also, in the embodiment, the process is divided based on "necessary / unnecessary" of the 3D-FEM model analysis in the control flow. However, it is not limited to this, and of course, it can also be configured to always perform the 3D-FEM model analysis.

[0060] Furthermore, the pressure control devices 8 and 8A in the embodiment and the modified example are not limited to being attached at the positions as shown in FIGS. 5 to 7. For example, as shown in FIGS. 5 to 7, it may be near the lower part of the partition wall 3, or near the middle part, or at the upper part.

Explanation of Reference Numerals

[0061] 1: Earth pressure shield 2: Skin plate 2a: Hood part 2b: Tail part 3: Partition wall 5: Cutter head 6: Displacement measuring means 7: Displacement measuring means 10: Cutter rotation shaft 11: Bearing 12: Cutter drive unit 13: Gear box 14: Rotation drive source 15: Erector 16: Chamber 17: Soil discharge device 18: Shield propulsion jack 19: Tail seal 21: Bentonite supply pipe 22: Pressure gauge 23: Water pressure gauge 40: Control unit 41: Analysis unit 42: Setting unit 43: Communication cable 51: Cutter spoke 52: Cutter bit 53: Fish tail bit 54: Agitator blade 61: Exploration 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 gauge) 8: Pressure control device 81: Recess 82: Jack 82a: Cylinder part 82b: Rod part 83: Support plate 8A: Pressure control device 84: Agitator blade (slide agitator blade) 85: Jack 85a: Cylinder part 85b: Rod part 86: Bracket 3a: Opening 90: Segment S: Setting system for management earth pressure F: Face

Claims

1. A pressure control device for controlling the pressure inside the chamber of a shield tunneling machine, comprising a volume change mechanism that changes the volume inside the chamber by moving at least a part outside the chamber.

2. The volume change mechanism includes a recess formed in the partition wall, a jack installed in the recess, and a support pressure plate attached to the front side of the jack. The support pressure plate is configured to be drawn inward into the machine from a reference position that forms the same plane as the partition wall by driving the jack to expand and contract. The pressure control device according to Claim 1.

3. The volume change mechanism includes a stirring blade protruding into the chamber from the partition wall and a jack attached to the back side of the stirring blade. The stirring blade is configured to be drawn inward into the machine from a reference position where it protrudes a predetermined amount from the partition wall by driving the jack to expand and contract. The pressure control device according to Claim 1.

4. A management earth pressure setting system for a shield tunneling machine, a pressure gauge for measuring the earth pressure inside the chamber, the pressure control device according to any one of Claims 1 to 3, displacement measuring means for measuring the displacement of the face, an analysis unit for analyzing the deformation characteristics of the ground based on the measured earth pressure and the measured displacement of the face, a setting unit for setting the management earth pressure based on the analyzed deformation characteristics, comprising a management earth pressure setting system.

5. When the shield tunneling machine stops, the earth pressure inside the chamber is reduced by the pressure control device, so that the active earth pressure can be obtained from the deformation of the ground by the analysis unit. The management earth pressure setting system according to Claim 4.

6. The analysis unit estimates the mechanical constants of the ground by inverse analysis based on the analyzed deformation characteristics of the ground, and updates the FEM model using the mechanical constants of the ground, and predicts the influence on the surrounding ground and / or structures using the updated FEM model. The management earth pressure setting system according to Claim 5.

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