Shield tunneling machine and method for measuring soil pressure of shield tunneling machine

Abstract

To provide a shield machine capable of continuously measuring the pressure caused by the moisture content of the earth and sand in a chamber, and a method for measuring the earth and sand pressure of the shield machine.SOLUTION: This shield machine 100 comprises a chamber 4, an interstitial mud water pressure gauge 9 for measuring the interstitial mud water pressure caused by the fine particles P and moisture contained in the earth and sand in the chamber 4, and an earth pressure gauge 8 for measuring the earth pressure of earth and sand in the chamber 4. The interstitial mud water pressure gauge 9 comprises a pressure receiving portion 92 that receives interstitial mud water pressure from earth and sand in the chamber 4, a filter portion 91 having an opening through which fine particles P contained in the earth and sand in the chamber 4 can pass, a housing portion 90 provided with an open portion 90a covered with the filter portion 91 and having a pressure receiving portion 92 disposed therein, and a fluid supply portion 93 provided in the housing portion 90 for supplying the fluid R to the inside of the housing portion 90.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a shield tunneling machine and a method for measuring soil pressure for a shield tunneling machine, and more particularly to a shield tunneling machine and a method for measuring soil pressure for a shield tunneling machine that measures the pressure of soil in a chamber. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a shield tunneling machine that measures the pressure of soil and sand inside a chamber and a method for measuring soil and sand pressure for a shield tunneling machine are known (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a shield machine equipped with an earth pressure chamber and a pore water pressure gauge that measures the pore water pressure of the soil in the earth pressure chamber. Although not specified in the above-mentioned Patent Document 1, the pore water pressure gauge is configured to capture soil particles using a filter section and pass only the moisture contained in the soil to the pressure receiving section. Therefore, the pore water pressure gauge is configured to measure the pressure (pore water pressure) caused only by the moisture contained in the soil, without measuring the pressure (effective stress) caused by the soil particles contained in the soil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2-43493 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the shield machine described in Patent Document 1, the filter section is configured to pass only the moisture contained in the soil to the pressure receiving section, so all soil particles must be captured by the filter section, which has the disadvantage that the pore water pressure gauge is prone to clogging with soil particles. This causes the problem that the pore water pressure gauge cannot continuously (repeatedly) measure the pressure caused by the moisture in the soil in the chamber.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a shield tunneling machine and a soil pressure measurement method for a shield tunneling machine that are capable of continuously measuring the pressure caused by moisture in the soil in a chamber. [Means for solving the problem]

[0007] In order to achieve the above object, the shield machine of the present invention comprises a chamber in which excavated soil is stored, a gap mud pressure gauge for measuring the gap mud pressure caused by fine particles and moisture contained in the soil in the chamber, and an earth pressure gauge for measuring the earth pressure of the soil in the chamber, the gap mud pressure gauge comprising a pressure receiving section which receives the gap mud pressure from the soil in the chamber, a filter section having an opening through which fine particles contained in the soil in the chamber can pass, a housing section which is provided with an opening covered by the filter section and in which the pressure receiving section is disposed, and a fluid supply section which is provided in the housing section and which supplies fluid to the inside of the housing section. The control unit further includes a predetermined threshold value for the content of the mud-adding material in the soil and a control unit for determining whether or not there is a shortage of mud-adding material in the chamber based on a comparison between the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at the predetermined threshold value and the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at the actual content rate of the mud-adding material in the soil. "Fine particles" refers to soil particles with a particle size of less than 0.075 mm.

[0008] In this shield machine, as described above, a pore mud pressure gauge is provided for measuring the pore mud pressure caused by the fine particles and moisture contained in the soil in the chamber, and a filter section is provided for the pore mud pressure gauge, which has an opening through which the fine particles contained in the soil in the chamber can pass and covers the open part of the housing section in which the pressure receiver is located. This makes it possible to prevent the fine particles from adhering to the filter section and causing clogging by passing the fine particles of the soil through the filter section having an opening through which the fine particles can pass, rather than capturing all the soil particles in the filter section as in the past. In addition, by providing a fluid supply section for supplying fluid to the inside of the housing section for the pore mud pressure gauge, even if clogging occurs in the filter section, the fluid supply section can supply fluid to the inside of the housing section, so that the supplied fluid can be used to clean the filter section and eliminate the clogging in the filter section. As a result of the above, the pore mud pressure gauge can continuously (repeatedly) measure the pressure caused by the moisture in the soil in the chamber. In addition, since the fine particles that pass through the filter are suspended in the pore water, they have almost no effect on the measurements taken by the pressure-receiving part of the pore mud pressure gauge. Also, by providing an earth pressure gauge, it is possible to obtain not only the pore mud pressure of the soil and sand in the chamber, but also the earth pressure, so that it is possible to more appropriately estimate the soil quality in the chamber based on the pore mud pressure and earth pressure obtained by the measurements.

[0009] In the above shield machine, the fluid supply unit is preferably configured to supply, to the inside of the casing, a fluid having a higher viscosity than the soil water (groundwater) contained in the natural ground to be excavated. With this configuration, the inside of the casing can be filled with a highly viscous fluid, so that it is possible to prevent low-viscosity soil water (groundwater) and soil particles containing fine particles from penetrating into the inside of the casing.

[0010] In the above shield machine, the filter section is preferably formed in a shape having an opening size of 0.075 mm or more and 0.125 mm or less. This configuration allows fine particles to pass through the filter section, while ensuring that the relatively large soil particles that are primarily responsible for the effective stress are captured by the filter section.

[0012] In this case, preferably, the control unit Compare the above The soil quality is estimated based on the above, and the mud-adding material to be supplied to the front side of the cutter head is judged to be insufficient. With this configuration, the soil quality is estimated and then it is judged whether the mud-adding material in the chamber is insufficient, so that it is possible to more appropriately judge whether the mud-adding material is insufficient. Therefore, it is possible to more appropriately impart the required plastic fluidity and water impermeability to the soil in the chamber.

[0013] In the above shield machine, the earth pressure gauge and the pore mud pressure gauge are preferably arranged at least one of the positions near the center of the partition wall forming the chamber and the position near the soil discharge device that discharges soil from the chamber when viewed from the front in the tunneling direction. With this configuration, when the earth pressure gauge and the pore mud pressure gauge are arranged near the center of the partition wall forming the chamber, it is possible to measure the earth pressure and the pore mud pressure of the soil in a location where soil is likely to remain because it is located on the inner periphery of the cutter head and where there is a tendency for mud-adding material to be insufficient. Also, when the earth pressure gauge and the pore mud pressure gauge are arranged near the soil discharge device that discharges soil from the chamber, it is possible to measure the earth pressure and the pore mud pressure of the soil in a location where the soil is moved vigorously by the soil discharge device and where the plastic fluidity and impermeability state are likely to change.

[0014] The method for measuring soil pressure for a shield machine of the present invention comprises the steps of: measuring the pore mud pressure caused by the fine particles and moisture contained in the soil in the chamber using a pressure-receiving part inside a housing part of a pore mud pressure gauge having a filter part with an opening through which fine particles can pass; and measuring the soil pressure of the soil in the chamber using an earth pressure gauge. The difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at a specified threshold value of the content of the mud material in the soil and the actual content of the mud material in the soil Difference between the measurements of the earth pressure gauge and the measurements of the pore mud pressure gauge Comparison with and a step of supplying fluid to the inside of the housing portion by a fluid supply portion of the pore mud pressure gauge before measuring the pore mud pressure with the pore mud pressure gauge.

[0015] In the method for measuring the soil pressure of a shield machine, as described above, a filter part is provided for the pore mud pressure gauge, which has an opening through which fine particles contained in the soil in the chamber can pass, and covers the open part of the housing part in which the pressure receiving part is disposed, and the pore mud pressure gauge measures the pore mud pressure caused by the fine particles and moisture contained in the soil in the chamber. This makes it possible to prevent the fine particles from adhering to the filter part and causing clogging by passing the fine particles of the soil through the filter part having an opening through which the fine particles can pass, rather than capturing all the soil particles in the filter part as in the conventional method. In addition, by providing a step of supplying fluid to the inside of the housing part by the fluid supply part, even if clogging occurs in the filter part, the fluid can be supplied to the inside of the housing part by the fluid supply part, so that the filter part can be washed with the supplied fluid and the clogging of the filter part can be eliminated. As a result of the above, the pore mud pressure gauge can continuously (repeatedly) measure the pressure caused by the moisture of the soil in the chamber. In addition, since the fine particles that pass through the filter are suspended in the pore water, they have almost no effect on the measurement value from the pressure receiver of the pore mud pressure gauge. Also, by providing a process for measuring earth pressure with an earth pressure gauge, it is possible to obtain not only the pore mud pressure of the soil and sand in the chamber, but also the soil pressure, so that it is possible to more appropriately estimate the soil quality in the chamber based on the pore mud pressure and earth pressure obtained by the measurement. Effect of the Invention

[0016] According to the present invention, as described above, the pressure caused by the moisture of the soil in the chamber can be continuously measured. [Brief description of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing a shield tunneling machine according to an embodiment from the side. [Diagram 2] FIG. 2 is a schematic front view of a bulkhead, an earth pressure gauge, and a pore mud pressure gauge of a shield machine according to an embodiment. [Diagram 3] FIG. 1 is a diagram for explaining the relationship between particle size and type of soil particles. [Figure 4] FIG. 2 is an enlarged cross-sectional side view of a pore mud pressure gauge according to an embodiment. [Diagram 5] FIG. 2 is an enlarged view of the mesh size (mesh size) of a pore mud pressure gauge according to an embodiment. [Figure 6] FIG. 13 is a diagram showing the relationship between the amount of mud-adding material injected into a gravel layer and the measured sediment pressure. [Figure 7] This is a diagram showing the relationship between the amount of mud additive injected into a clay layer and the measured soil pressure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] [Embodiment] A shield machine 100 according to an embodiment will be described with reference to Figs. 1 to 7.

[0020] (Overall configuration of the shield tunneling machine) The shield machine 100 shown in Fig. 1 is a machine used for tunnel construction by the shield method. The shield machine 100 is a so-called mud pressure type machine.

[0021] As shown in Figure 1, the shield tunneling machine 100 comprises a cutter head 1, a cylindrical body 2, a partition wall 3, a chamber (mud working chamber) 4, a driving jack 5, a soil discharge device 6, a mud injection device 7, an earth pressure gauge 8, a pore mud pressure gauge 9, and a control unit 10.

[0022] In each drawing, the front-to-rear direction of the shield machine 100 is indicated by the X direction, the excavation direction (forward) within the X direction is indicated by the X1 direction, and the opposite direction to the excavation direction (rear) is indicated by the X2 direction.

[0023] In each drawing, the up-down direction of the shield machine 100 is indicated as the Z direction, the upper side of the Z direction is indicated as the Z1 direction, and the lower side is indicated as the Z2 direction.

[0024] In each drawing, the left-right direction (width direction) of the shield machine 100 is indicated by the Y direction. Note that the Y direction is perpendicular to both the X direction and the Z direction.

[0025] In each drawing, the axis located at the center of rotation of the cutter head 1 is indicated by a central rotation axis α.

[0026] The cutter head 1 is configured to move forward in the excavation direction as it rotates about a central axis of rotation α extending in the excavation direction, thereby excavating the natural ground. The cutter head 1 is provided with a cutter drive unit 1a that applies a rotational force about the central axis of rotation α. ​​The cutter drive unit 1a is configured, for example, by a hydraulic motor. The rotation of the cutter head 1 is configured so that it can be switched between forward and reverse rotation depending on the excavation situation, etc.

[0027] The fuselage 2 is composed of a forward fuselage 2a and a rear fuselage 2b. A cutter head 1 is installed at the front end of the forward fuselage 2a in the excavation direction. The rear fuselage 2b is the section that advances while arranging segments SG on the wall surface by an erector (not shown) to form the circumferential wall of the tunnel as the forward fuselage 2a excavates. The internal space of the fuselage 2 is divided by a partition wall 3 into two spaces: a chamber 4 on the excavation direction side and a working space WS behind the chamber 4.

[0028] The chamber 4 is a space for storing the soil excavated by the cutter head 1. The chamber 4 is formed by the rear surface of the cutter head 1, the inner surface of the body 2, and the front surface of the partition wall 3. In other words, the chamber 4 is a space surrounded by the cutter head 1, the body 2, and the partition wall 3. The mud pressure in the chamber 4 is maintained in approximate equilibrium with the pressure acting on the cutter head 1 from the natural ground by adjusting the amount of mud-adding material injected into the chamber 4.

[0029] In detail, in the mud pressure type shield machine 100, mud is injected by the mud injection device 7 into the front side of the cutter head 1 and mixed with the excavated soil, converting the excavated soil into mud with impermeability and plastic flowability, which fills the chamber 4. The shield machine 100 maintains the chamber 4 filled with the excavated soil (mud) and generates mud pressure in the chamber 4 by the thrust of the driving jack 5, thereby countering the pressure on the natural ground (earth pressure at the face and groundwater pressure). The shield machine 100 excavates while maintaining a pressure balance by balancing the amount of excavation and the amount of soil discharged. If the amount of mud injected by the mud injection device 7 is insufficient, the pressure balance cannot be maintained properly, which may cause problems such as the collapse of the natural ground and the breakdown of the shield machine 100.

[0030] In detail, when there is a "lack of mud-adding material", the balance between the mud pressure generated in the chamber 4 and the pressure on the ground side (earth pressure at the face and groundwater pressure) cannot be properly maintained, which may result in the collapse of the ground. Also, when there is a "lack of mud-adding material", the soil in the chamber 4 is not endowed with the necessary impermeability and plastic fluidity, which may prevent the soil from being properly discharged by the soil discharge device 6.

[0031] In order to prevent such problems, the shield machine 100 (control unit 10) is configured to determine whether or not there is a shortage of mud-adding material in the chamber 4, based on the difference between the measurement value of the earth pressure gauge 8 and the measurement value of the pore mud pressure gauge 9. Details will be described later.

[0032] The propulsion jack 5 is configured to push the segments SG backward (in the X2 direction) to propel the shield machine 100. A plurality of propulsion jacks 5 are provided so as to be aligned along the circumferential direction of the body 2.

[0033] The soil discharge device 6 is configured, for example, by a screw conveyor. An opening 6a at the front end of the soil discharge device 6 communicates with the lower side of the chamber 4. The soil discharge device 6 is configured to take in soil from the chamber 4 and discharge it into the work space WS by rotating an internal screw 60. The soil discharged from the soil discharge device 6 to the work space WS is transported toward the outside of the pit by a soil transporting device (not shown) such as a belt conveyor.

[0034] The mud adding material injection device 7 is configured to inject mud adding material into the front side of the cutter head 1. As one example, the mud adding material is a material added to soil and sand whose main component is bentonite. The mud adding material injection device 7 includes a mud adding material injection pipe 70 that communicates with the front side of the cutter head 1, and a mud adding material injection pump (not shown) that pressure-feeds the mud adding material into the mud adding material injection pipe 70. The mud adding material injection device 7 is configured so that the amount of mud adding material injected into the front side of the cutter head 1 can be freely adjusted.

[0035] (Configuration of earth pressure gauge and pore mud pressure gauge) As shown in FIG. 2, if one earth pressure gauge 8 and one gap mud pressure gauge 9 constitute one set, five sets of earth pressure gauges 8 and gap mud pressure gauges 9 are provided on the bulkhead 3 of the shield machine 100.

[0036] The earth pressure gauge 8 and pore mud pressure gauge 9 of each set are disposed at approximately the same height. The earth pressure gauge 8 and pore mud pressure gauge 9 of each set are disposed adjacent to each other in the left-right direction (Y direction) and in close proximity to each other. As an example, the separation distance between the earth pressure gauge and the pore mud pressure gauge may be 5 times or less the diameter of the earth pressure gauge.

[0037] One of the five sets of earth pressure gauges 8 and pore mud pressure gauges 9 is positioned near the center of the bulkhead 3 when viewed from the excavation direction. "Near the center of the bulkhead 3" means either the center of the bulkhead 3 or a position slightly away from the center of the bulkhead 3.

[0038] Another set of the five sets of earth pressure gauges 8 and pore mud pressure gauges 9 is disposed in the vicinity of the soil discharge device 6 that discharges soil from the chamber 4 when viewed from the excavation direction. "In the vicinity of the soil discharge device 6" means either a position adjacent to the opening 6a of the soil discharge device 6 or a position slightly spaced apart from the opening 6a. In detail, the other set of the five sets of earth pressure gauges 8 and pore mud pressure gauges 9 is disposed below the opening 6a of the soil discharge device 6.

[0039] The remaining three of the five sets of earth pressure gauges 8 and pore mud pressure gauges 9 are positioned, when viewed from the excavation direction, directly above (in the Z1 direction) the central set (earth pressure gauge 8 and pore mud pressure gauge 9), to the left of the central set (on one side of the Y direction), and to the right of the central set (on the other side of the Y direction).

[0040] The earth pressure gauge 8 shown in Fig. 1 is configured to measure the earth pressure of the soil in the chamber 4. The earth pressure gauge 8 is configured such that a pressure-receiving portion is directly exposed in the chamber 4, and the pressure-receiving portion is in direct contact with the soil in the chamber 4. Therefore, the earth pressure gauge 8 is configured to measure the pressure from the soil particles (effective stress) and the pressure from moisture contained in the soil as earth pressure.

[0041] The pore mud pressure gauge 9 is configured to measure the pore mud pressure caused by the fine particles P (see FIG. 5) and moisture contained in the soil in the chamber 4 (see FIG. 3). As one example, "fine particles P" refers to soil particles with a particle size of less than 0.075 mm. In other words, "fine particles P" are soil particles with a small particle size. Note that soil particles with a particle size larger than that of the "fine particles P" are called "coarse particles." "Coarse particles" include sand such as fine sand and gravel.

[0042] As shown in FIG. 4, the gap muddy water pressure gauge 9 includes a housing portion 90 , a filter portion 91 , a pressure receiving portion 92 , and a fluid supply portion 93 .

[0043] The housing 90 of the gap mud pressure gauge 9 is formed to be hollow. A pressure receiving part 92 is disposed inside the housing 90. An opening 90a is provided at the front end of the housing 90.

[0044] The filter portion 91 of the gap mud pressure gauge 9 is attached to the housing portion 90 so as to cover the open portion 90a. That is, the filter portion 91 separates the internal space of the housing portion 90 in which the pressure receiving portion 92 is disposed from the inside of the chamber 4. The filter portion 91 is formed in a net shape having openings 91a through which the fine particles P contained in the soil and sand in the chamber 4 can pass. As an example, the filter portion 91 is formed by weaving linear fibers into a lattice shape. That is, the filter portion 91 is provided with an infinite number of rectangular openings (holes) 91a arranged in a matrix.

[0045] As an example, the filter portion 91 is formed in a net shape having openings 91a of 0.075 mm or more and 0.125 mm or less. That is, the size L of one side of the rectangular openings (holes) 91a is 0.075 mm or more and 0.125 mm or less (see FIG. 5). Therefore, the openings 91a of the filter portion 91 are larger than the fine particles P, and therefore the fine particles P can pass through.

[0046] The pressure receiving part 92 of the pore mud pressure gauge 9 is configured to receive pore mud pressure from the soil and sand in the chamber 4. It is a pressure sensor that measures pore mud pressure. As an example, the pressure receiving part 92 is configured to generate an electrical signal corresponding to the magnitude of the pore mud pressure and measure the pore mud pressure electrically. Note that the pressure receiving part 92 may also be configured to measure the pore mud pressure mechanically.

[0047] Here, the so-called "pore water pressure gauge" is configured to prevent soil particles from entering the space in which the pressure receiver is placed by using a filter part with extremely small openings, and to measure the pressure caused by pure moisture only. The pore mud pressure gauge 9 of this embodiment has a filter part 91 with openings 91a of 0.075 mm to 0.125 mm, which is larger than the openings of a "pore water pressure gauge."

[0048] As a result, the pore mud pressure gauge 9 of this embodiment is configured to be able to measure not only the pressure caused by moisture but also the pressure caused by the fine particles P. Furthermore, the pore mud pressure gauge 9 of this embodiment is purposely formed with the filter portion 91 so that the fine particles P can pass through, thereby preventing the filter portion 91 from being clogged with the fine particles P caused by the fine particles P adhering to and being captured by the filter portion 91. In this way, the pore mud pressure gauge 9 has a configuration in which the filter portion 91 is less likely to be clogged with soil particles.

[0049] In addition, the fine particles P that pass through the filter section 91 are suspended in the interstitial water and therefore have almost no effect on the measurement by the pressure receiving section 92. In other words, under the same measurement environment, there is almost no difference in the measured value when the pressure of the soil and sand in the chamber 4 is measured by a "pore water pressure gauge" and when the pressure of the soil and sand in the chamber 4 is measured by a pore mud pressure gauge 9.

[0050] The fluid supply unit 93 of the pore mud pressure gauge 9 is provided in the housing 90 and is configured to supply the fluid R to the inside of the housing 90. The fluid supply unit 93 supplies the fluid R to the inside of the housing 90 before the pore mud pressure gauge 9 measures the pore mud pressure.

[0051] The fluid supply unit 93 includes a fluid supply pipe 93a, a fluid storage unit 93b, and a fluid supply pump 93c.

[0052] One end of the fluid supply pipe 93a is connected to the inside of the housing part 90. The fluid storage part 93b is connected to the other end of the fluid supply pipe 93a, and stores the fluid R to be supplied to the inside of the housing part 90. The fluid supply pump 93c is configured to pump the fluid R into the inside of the housing part 90.

[0053] The fluid supply unit 93 is configured to supply, as the fluid R, a highly viscous fluid R having a viscosity greater than that of soil water (groundwater) contained in the ground to be excavated, to the inside of the housing unit 90. As an example, the "highly viscous fluid R" is grease or a highly viscous type mud-adding material (a polymer-based mud-adding material, a highly water-absorbent resin-based mud-adding material), etc.

[0054] The fluid supply unit 93 is configured to supply the highly viscous fluid R to the inside of the housing unit 90 to fill the inside of the housing unit 90 with the highly viscous fluid R. When the highly viscous fluid R is filled inside the housing unit 90, the moisture and fine particles P (see FIG. 5) are prevented from penetrating from the chamber 4 into the inside of the housing unit 90 through the filter unit 91. In addition, when the highly viscous fluid R is filled inside the housing unit 90, the diffusion of the highly viscous fluid R to the outside of the housing unit 90 where low-viscosity soil water is present is prevented, and the highly viscous fluid R can be kept inside the housing unit 90.

[0055] The fluid supply unit 93 is configured to supply the highly viscous fluid R to the inside of the housing unit 90 to fill the inside of the housing unit 90 with the highly viscous fluid R, and to pass the highly viscous fluid R through the filter unit 91 to cause the highly viscous fluid R to flow from the inside of the housing unit 90 to the outside. In this way, the fluid supply unit 93 is configured to wash (backwash) the filter unit 91 with the highly viscous fluid R. As a result, relatively fine soil particles adhering to the filter unit 91 and relatively coarse soil particles stuck in the filter unit 91 are removed from the filter unit 91. In this way, the pore mud pressure gauge 9 has a configuration that allows the fluid supply unit 93 to remove soil particles from the filter unit 91.

[0056] Therefore, since the pore mud pressure gauge 9 is configured so that soil particles do not easily become clogged in the filter section 91, and so that soil particles can be removed from the filter section 91 by the fluid supply section 93, it is possible to continuously and repeatedly perform highly accurate measurements even within the chamber 4.

[0057] (Control Unit Configuration) As an example, the control unit 10 shown in FIG. 1 is a circuit board including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like.

[0058] The control unit 10 is configured to determine whether or not there is a shortage of mud adding material in the chamber 4 based on the difference (difference) between the measurement value of the earth pressure gauge 8 and the measurement value of the pore mud pressure gauge 9. In detail, the control unit 10 is configured to determine whether or not there is a shortage of mud adding material in the chamber 4 by estimating the soil type based on the difference (difference) between the measurement value of the earth pressure gauge 8 and the measurement value of the pore mud pressure gauge 9. The control unit 10 is provided with an output device 10a that outputs a control result such as a shortage of mud adding material. As one example, the output device 10a is configured by a display or the like.

[0059] Here, an example of the relationship between the measurements of the earth pressure gauge 8 and the pore mud pressure gauge 9 and the injection of mud-adding material into the chamber 4 will be described. In the description, a "gravel layer" consisting of relatively coarse soil particles and a "clay layer" consisting of relatively fine soil particles will be described in that order. Whether the ground is composed of a "gravel layer" or a "clay layer" is determined by a boring survey or the like carried out prior to excavation by the shield tunneling machine 100. In the graphs of Figures 6 and 7 described below, the horizontal axis indicates the mud-adding material content of the soil in the chamber 4, and the vertical axis indicates the ratio of the measurements of the pore mud pressure gauge 9 of the soil in the chamber 4 to the measurements of the earth pressure gauge 8 of the soil in the chamber 4.

[0060] About the Gravel Layer First, the case of the "gravel layer" shown in Figure 6 will be described. The ratio of the measurement value of the pore mud pressure gauge 9 to the measurement value of the earth pressure gauge 8 gradually increases as the mud additive content increases. Then, when the mud additive content reaches A1, the ratio of the measurement value of the pore mud pressure gauge 9 increases at a rapid rate. Furthermore, when the mud additive content reaches A2, which is greater than A1, the ratio of the measurement value of the pore mud pressure gauge 9 increases at a slower rate again.

[0061] The reason for the fluctuation in the ratio of the measurement value of the pore mud pressure gauge 9 to the measurement value of the earth pressure gauge 8 as described above is thought to be that below A1, many of the soil particles that make up the gravel layer are in contact with each other (contact state), whereas above A2, many of the soil particles that make up the gravel layer are suspended in the mud-adding material and separated from each other (floating state).

[0062] Therefore, at least when the mud content is less than A2, and especially when it is less than A1, the mud is trapped between the soil particles that make up the gravel layer, and the mud is not able to adequately transmit the face pressure, but is insufficient. In other words, at least when the mud content is less than A2, the plastic fluidity and impermeability are insufficient.

[0063] As one example, if the difference between the ratio of the measurement value of the earth pressure gauge 8 and the ratio of the measurement value of the pore mud pressure gauge 9 obtained by actual measurement is greater than the difference between the ratio of the measurement value of the earth pressure gauge 8 and the ratio of the measurement value of the pore mud pressure gauge 9 at the mud addition threshold value T1, it can be determined that there is an insufficient supply of mud addition material into the chamber 4. Note that threshold value T1 is set to a predetermined value that is at least equal to or greater than A2.

[0064] In other words, the control unit 10 is configured to determine whether or not there is a shortage of mud-adding material in the chamber 4 by estimating the soil quality by comparing the difference between the ratio of the measurement values ​​of the earth pressure gauge 8 obtained by actual measurement and the ratio of the measurement values ​​of the pore mud pressure gauge 9 and the difference between the ratio of the measurement values ​​of the earth pressure gauge 8 and the ratio of the measurement values ​​of the pore mud pressure gauge 9 at threshold value T1.

[0065] The control unit 10 can make a judgment using the threshold value T1 as described above only after data on measurements from the earth pressure gauge 8 and the pore mud pressure gauge 9 obtained during actual excavation by the shield machine 100 has been accumulated. In other words, threshold value T1 can only be set after data on measurements from the earth pressure gauge 8 and the pore mud pressure gauge 9 has been accumulated.

[0066] Therefore, at least until the above-mentioned data is accumulated, the control unit 10 is configured to determine whether or not there is a shortage of mud adding material in the chamber 4 by estimating soil changes based on the change over time in the difference (difference) between the ratio of measurements from the earth pressure gauge 8 and the ratio of measurements from the pore mud pressure gauge 9. As one example, "estimating soil changes based on the change over time in the difference (difference) between the ratio of measurements from the earth pressure gauge 8 and the ratio of measurements from the pore mud pressure gauge 9" includes estimating that there may be a shortage of mud adding material due to a sudden and large change in the difference (difference) between the ratio of measurements from the earth pressure gauge 8 and the ratio of measurements from the pore mud pressure gauge 9 during time changes associated with actual excavation by the shield machine 100.

[0067] About the clay layer Next, the case of the "clay layer" shown in FIG. 7 will be described. The ratio of the measurement value of the pore mud pressure gauge 9 to the measurement value of the earth pressure gauge 8 gradually increases as the mud content increases. Note that, unlike the case of the "gravel layer", there is no inflection point at which the ratio of the measurement value of the pore mud pressure gauge 9 to the measurement value of the earth pressure gauge 8 changes significantly. When the supply of the mud material is small, the plastic fluidity decreases and the soil becomes a hard mass with a high density, making it difficult for the soil to pass through the filter part 91 of the pore mud pressure gauge 9, and the ratio of the measurement value of the pore mud pressure gauge 9 becomes smaller compared to the earth pressure gauge 8. On the other hand, when the mud material is sufficiently supplied, the plastic fluidity increases and the soil becomes a soft clay mass, making it easier for the soil to pass through the filter part 91 of the pore mud pressure gauge 9, and the ratio of the measurement value of the pore mud pressure gauge 9 becomes larger.

[0068] As one example, if the difference between the ratio of the measured values ​​of the earth pressure gauge 8 and the ratio of the measured values ​​of the pore mud pressure gauge 9 obtained by actual measurement is greater than the difference between the ratio of the measured values ​​of the earth pressure gauge 8 and the ratio of the measured values ​​of the pore mud pressure gauge 9 at the mud addition threshold value T2, it can be determined that there is an insufficient supply of mud addition material into the chamber 4. Note that the threshold value T2 is set to a predetermined value that is at least less than A3 of the mud addition material. A3 is the mud addition material content when the ratio of the measured values ​​of the earth pressure gauge 8 and the ratio of the measured values ​​of the pore mud pressure gauge 9 are approximately equal.

[0069] In other words, the control unit 10 is configured to determine whether or not there is a shortage of mud-adding material in the chamber 4 by estimating the soil quality by comparing the difference between the ratio of the measurement values ​​of the earth pressure gauge 8 and the ratio of the measurement values ​​of the pore mud pressure gauge 9 obtained by actual measurement and the difference between the ratio of the measurement values ​​of the earth pressure gauge 8 and the ratio of the measurement values ​​of the pore mud pressure gauge 9 at threshold value T2.

[0070] The control unit 10 can make the above-mentioned judgment using threshold value T2 only after accumulating data on measurements from the earth pressure gauge 8 and the pore mud pressure gauge 9 obtained during actual excavation by the shield machine 100. In other words, threshold value T2 can only be set after accumulating data on measurements from the earth pressure gauge 8 and the pore mud pressure gauge 9.

[0071] Therefore, at least until the above-mentioned data is accumulated, the control unit 10 is configured to determine whether or not there is a shortage of mud adding material in the chamber 4 by estimating soil changes based on the change over time in the difference (difference) between the ratio of measurements from the earth pressure gauge 8 and the ratio of measurements from the pore mud pressure gauge 9. As one example, "estimating soil changes based on the change over time in the difference (difference) between the ratio of measurements from the earth pressure gauge 8 and the ratio of measurements from the pore mud pressure gauge 9" includes estimating that there may be a shortage of mud adding material due to a sudden and large change in the difference (difference) between the ratio of measurements from the earth pressure gauge 8 and the ratio of measurements from the pore mud pressure gauge 9 during time changes associated with actual excavation by the shield machine 100.

[0072] (Method of measuring sediment pressure) A description will now be given of a method for measuring soil pressure using the shield machine 100. The soil pressure measuring method includes the following steps.

[0073] The sediment pressure measurement method includes a step of supplying a highly viscous fluid R to the inside of the housing 90 of the pore mud pressure gauge 9 by a fluid supply unit 93 provided in the housing 90 of the pore mud pressure gauge 9 before measuring the pore mud pressure with the pore mud pressure gauge 9. As a result, the inside of the housing 90 is filled with the highly viscous fluid R, and if soil particles are attached to the filter unit 91, the highly viscous fluid R removes the soil particles from the filter unit 91. This prepares the pore mud pressure gauge 9 for measurement.

[0074] The method for measuring sediment pressure also includes a step of measuring the pore mud pressure caused by the fine particles P and moisture contained in the sediment in the chamber 4 using a pressure-receiving part 92 disposed inside a housing part 90 of a pore mud pressure gauge 9 having a mesh-like filter part 91 with mesh openings 91a through which the fine particles P (see FIG. 5) contained in the sediment in the chamber 4 can pass. In this case, the pore mud pressure gauge 9 measures not only the moisture contained in the sediment but also the pressure caused by the fine particles P. However, since the fine particles P are particularly small among soil particles, they have almost no effect on the measurement by the pressure-receiving part 92. The measurement by the pore mud pressure gauge 9 is performed while the cutter head 1 is stopped.

[0075] The soil pressure measuring method also includes a step of measuring the soil pressure of the soil in the chamber 4 by an earth pressure gauge 8 arranged near the pore mud pressure gauge 9. Measurement by the earth pressure gauge 8 is usually performed at approximately the same time as measurement by the pore mud pressure gauge 9. Measurement by the earth pressure gauge 8 is performed while the cutter head 1 is stopped.

[0076] The sediment pressure measurement method also includes a step of judging whether or not there is a shortage of mud adding material in the chamber 4 based on the difference (difference) between the ratio of the measurement values ​​of the earth pressure gauge 8 and the ratio of the measurement values ​​of the pore mud pressure gauge 9. As a specific example, by estimating a change in soil quality based on the change over time in the difference (difference) between the ratio of the measurement values ​​of the earth pressure gauge 8 and the ratio of the measurement values ​​of the pore mud pressure gauge 9, it is judged whether or not there is a shortage of mud adding material to be supplied to the chamber 4. In addition, if data on the measurements of the earth pressure gauge 8 and the pore mud pressure gauge 9 is accumulated, a predetermined threshold value T1 or T2 is set for the mud adding material content, and then a soil change is estimated to judge whether or not there is a shortage of mud adding material to be supplied to the chamber 4.

[0077] (Effects of the embodiment) In this embodiment, the following effects can be obtained.

[0078] In this embodiment, as described above, the pore mud pressure gauge 9 is provided to measure the pore mud pressure caused by the fine particles P and moisture contained in the soil in the chamber 4, and the filter part 91 is provided to cover the open part 90a of the housing part 90 in which the pressure receiving part 92 is disposed, and has a mesh (opening) 91a through which the fine particles P contained in the soil in the chamber 4 can pass. This allows the fine particles P of the soil to pass through the filter part 91 having the mesh 91a through which the fine particles P can pass, rather than capturing all the soil particles in the filter part 91 as in the conventional method, thereby preventing the fine particles P from adhering to the filter part 91 and causing clogging. In addition, by providing the pore mud pressure gauge 9 with a fluid supply part 93 that supplies the fluid R to the inside of the housing part 90, even if the filter part 91 becomes clogged, the fluid supply part 93 can supply the fluid R to the inside of the housing part 90, so that the filter part 91 can be washed with the supplied fluid R to eliminate clogging of the filter part 91. As a result of the above, the pore mud pressure gauge 9 can continuously (repeatedly) measure the pressure caused by the moisture in the soil and sand in the chamber 4. The fine particles P that pass through the filter section 91 are suspended in the pore water, and therefore have almost no effect on the measurement value measured by the pressure receiving section 92 of the pore mud pressure gauge 9. Furthermore, by providing the earth pressure gauge 8, not only the pore mud pressure of the soil and sand in the chamber 4 can be obtained, but also the earth pressure, so that the soil quality in the chamber 4 can be more appropriately estimated based on the pore mud pressure and earth pressure obtained by measurement.

[0079] In this embodiment, as described above, the fluid supply unit 93 is configured to supply the fluid R having a higher viscosity than the soil water (groundwater) contained in the ground to be excavated to the inside of the casing 90. This allows the highly viscous fluid R to be filled inside the casing 90, thereby preventing the soil particles containing the soil water (groundwater) and fine particles P having a low viscosity from penetrating into the inside of the casing 90.

[0080] In this embodiment, as described above, the filter portion 91 is formed in a shape having openings 91a of 0.075 mm or more and 0.125 mm or less. This allows the fine particles P to pass through the filter portion 91, and also allows the filter portion 91 to reliably capture the relatively large soil particles that mainly bear the effective stress.

[0081] As described above, this embodiment further includes a control unit 10 that determines whether or not there is a shortage of mud adding material in the chamber 4 based on the difference between the measurement values ​​of the earth pressure gauge 8 and the pore mud pressure gauge 9. This makes it possible to determine whether or not there is a shortage of mud adding material in the chamber 4 based on the difference between the measurement values ​​of the earth pressure gauge 8 and the pore mud pressure gauge 9, so that when it is determined that there is a shortage of mud adding material, the mud adding material can be supplied to appropriately impart the required plastic fluidity and impermeability to the soil in the chamber 4.

[0082] In this embodiment, as described above, the control unit 10 is configured to estimate the soil quality based on the difference between the measurement value of the earth pressure gauge 8 and the measurement value of the pore mud pressure gauge 9, thereby determining whether or not there is a shortage of mud adding material to be supplied to the front side of the cutter head 1. This makes it possible to determine whether or not there is a shortage of mud adding material in the chamber 4 after estimating the soil quality, and therefore makes it possible to more appropriately determine whether or not there is a shortage of mud adding material. This makes it possible to more appropriately impart the required plastic fluidity and impermeability to the soil in the chamber 4.

[0083] In this embodiment, as described above, the earth pressure gauge 8 and the pore mud pressure gauge 9 are disposed at least one of the positions near the center of the partition wall 3 forming the chamber 4 and the positions near the soil discharge device 6 that discharges soil from the chamber 4, as viewed from the front in the excavation direction. In this way, when the earth pressure gauge 8 and the pore mud pressure gauge 9 are disposed near the center of the partition wall 3 that forms the chamber 4, it is possible to measure the earth pressure and pore mud pressure of the soil in a location where soil is likely to remain because it is located on the inner periphery side of the cutter head and where there is a tendency for mud-adding material to be insufficient. In addition, when the earth pressure gauge 8 and the pore mud pressure gauge 9 are disposed near the soil discharge device 6 that discharges soil from the chamber 4, it is possible to measure the earth pressure and pore mud pressure of the soil in a location where the soil is moved vigorously by the soil discharge device 6 and where the plastic fluidity and impermeability state are likely to change.

[0084] [Variations] The embodiments and modifications disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (modifications) within the meaning and scope equivalent to the claims.

[0085] For example, in the above embodiment, the fluid supplied from the fluid supply unit is a highly viscous fluid having a higher viscosity than the soil water contained in the ground to be excavated, but the present invention is not limited to this. In the present invention, the fluid supplied from the fluid supply unit may be a fluid having a lower viscosity than the soil water contained in the ground to be excavated.

[0086] In the above embodiment, an example in which five sets of earth pressure gauges and pore mud pressure gauges are provided is shown, but the present invention is not limited to this. In the present invention, one to four sets, or six or more sets of earth pressure gauges and pore mud pressure gauges may be provided.

[0087] In the above embodiment, the filter portion is shown to have a mesh shape and openings, but it may have a staggered shape, a honeycomb structure, or a structure such as punched metal. The filter portion does not have to be mesh-shaped as long as it can pass fine particles.

[0088] In the above embodiment, the size of the openings in the filter portion is 0.075 mm or more and 0.125 mm or less, but the present invention is not limited to this. In the present invention, the size of the openings in the filter portion may be a size other than 0.075 mm or more and 0.125 mm or less, as long as fine particles can pass through.

[0089] In the above embodiment, the mud adding material is supplied to the front side of the cutter head, but the present invention is not limited to this. In the present invention, the mud adding material may be supplied directly into the chamber. The control unit may estimate the soil type based on the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge, and determine whether or not there is a shortage of mud adding material to be supplied into the chamber.

[0090] Furthermore, the arrangement of the earth pressure gauge and pore mud pressure gauge relative to the partition wall shown in the above embodiment is merely one example, and the earth pressure gauge and pore mud pressure gauge may be arranged relative to the partition wall at a position different from that in the above embodiment.

[0091] In the above embodiment, the earth pressure gauge and the pore mud pressure gauge are provided on the bulkhead, but the present invention is not limited to this. In the present invention, the earth pressure gauge and the pore mud pressure gauge may be provided on the inner circumferential surface of the body or the rear surface of the cutter head.

[0092] In the above embodiment, the shield machine is provided with a control unit that performs predetermined control based on the measured values ​​of the earth pressure gauge and the pore mud pressure gauge, but the present invention is not limited to this. In the present invention, the shield machine does not need to be provided with a control unit. In this case, the measured values ​​of the earth pressure gauge and the pore mud pressure gauge are output as they are. [Explanation of symbols]

[0093] 1 Cutter Head 3 Bulkhead 4. Chamber 6. Sediment discharge device 8 Earth pressure gauge 9. Pore Mud Pressure Gauge 10 Control section 90 (Pore mud pressure gauge) housing 90a (Opening of the housing) 91 Filter part (of pore mud pressure gauge) 91a (pore mud pressure gauge) aperture 92 (Pore mud pressure gauge) pressure receiving part 93 Fluid supply (for pore mud pressure gauge) 100 Shield tunneling machine P Fine particle content R fluid

Claims

1. a chamber in which the excavated soil is stored; a pore mud pressure gauge for measuring pore mud pressure caused by fine particles and moisture contained in the soil in the chamber; an earth pressure gauge for measuring the earth pressure of the soil in the chamber; The pore mud pressure gauge is a pressure receiving portion that receives pore mud pressure from the soil in the chamber; a filter section having an opening through which the fine particles contained in the sediment in the chamber can pass; a housing portion having an open portion covered by the filter portion and in which the pressure receiving portion is disposed; a fluid supply unit provided in the housing unit and supplying a fluid to an inside of the housing unit, A predetermined threshold value is set for the content of the mud-adding material in the soil and sand, The shield tunneling machine further comprises a control unit which determines whether or not there is a shortage of mud adding material in the chamber based on a comparison between the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at the specified threshold value and the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at the actual content of the mud adding material in the soil.

2. The shield machine according to claim 1, wherein the fluid supply unit is configured to supply, as the fluid, a fluid having a viscosity greater than that of soil water contained in the ground to be excavated into the inside of the housing unit.

3. The shield machine according to claim 1 or 2, wherein the filter portion is formed in a shape having an opening of 0.075 mm or more and 0.125 mm or less.

4. The shield machine according to claim 1, wherein the control unit is configured to determine whether or not there is a shortage of the mud-adding material supplied to the front side of the cutter head by estimating soil type based on the comparison.

5. A shield tunneling machine as described in any one of claims 1 to 4, wherein the earth pressure gauge and the gap mud water pressure gauge are positioned at least one of a position near the center of the partition wall forming the chamber and a position near a soil discharge device that discharges soil from within the chamber, when viewed from the front in the excavation direction.

6. A step of measuring the pore mud pressure caused by the fine particles and moisture contained in the soil in the chamber using a pressure receiving part inside a housing part of a pore mud pressure gauge having a filter part with an opening through which fine particles can pass; measuring the soil pressure of the soil in the chamber with an earth pressure gauge; determining whether or not there is a shortage of the mud-adding material in the chamber based on a comparison between the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at a predetermined threshold value of the mud-adding material content in the soil and the difference between the measurement value of the earth pressure gauge and the measurement value of the pore mud pressure gauge at the actual content rate of the mud-adding material in the soil; A method for measuring soil pressure in a shield machine, comprising the step of supplying fluid into the inside of the casing unit by a fluid supply unit of the pore mud pressure gauge before measuring the pore mud pressure with the pore mud pressure gauge.

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