JP2023000042A - Shield machine and method for measuring earth and sand pressure of shield machine - Google Patents

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 The present invention relates to a shield machine and a soil pressure measuring method for the shield machine, and more particularly to a shield machine for measuring the pressure of soil in a chamber and a soil pressure measuring method for the shield machine.

2. Description of the Related Art Conventionally, a shield machine for measuring the pressure of earth and sand in a chamber and a method for measuring the earth and sand pressure of the shield machine are known (see, for example, Patent Document 1).

The aforementioned Patent Document 1 discloses a shield tunneling machine that includes an earth pressure chamber (chamber) and a pore water pressure gauge that measures the pore water pressure of earth and sand in the earth pressure chamber. Here, although not specified in Patent Document 1, the pore water pressure gauge is configured such that the filter section captures soil particles and allows only moisture contained in the soil to pass through to the pressure receiving section side. Therefore, the pore water pressure gauge is configured to measure the pressure (pore water pressure) caused only by the moisture contained in the sediment without measuring the pressure (effective stress) caused by the soil particles contained in the sediment. .

JP-A-2-43493

However, in the shield machine described in Patent Document 1, the filter section is configured to allow only the moisture contained in the earth and sand to pass through to the pressure receiving section side, so it is not necessary to capture all soil particles by the filter section. There is a problem that the pore water pressure gauge is easily clogged by soil particles. Therefore, there is a problem that the pore water pressure gauge cannot continuously (repeatedly) measure the pressure caused by the moisture content of the sediment in the chamber.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a shield excavation apparatus capable of continuously measuring the pressure caused by the moisture content of earth and sand in a chamber. To provide a sediment pressure measuring method for machine and shield machine.

In order to achieve the above object, the shield machine of the present invention comprises a chamber in which excavated earth and sand is stored, and a pore mud water pressure caused by fine grains and moisture contained in the earth and sand in the chamber. Equipped with a pressure gauge and a soil pressure gauge for measuring the soil pressure of the soil in the chamber, the pore mud water pressure gauge includes a pressure receiving part that receives the pore mud water pressure from the soil in the chamber, and a fine particle contained in the soil in the chamber. A filter portion having an opening through which passage is possible, a housing portion provided with an open portion covered by the filter portion, and a pressure receiving portion disposed therein, and a housing portion provided in the housing portion for supplying a fluid to the inside of the housing portion. and a fluid supply. The term "fine particles" means soil particles having a particle size of less than 0.075 mm.

In this shield machine, as described above, a pore mud pressure gauge is provided for measuring the pore mud water pressure caused by fine particles and moisture contained in the soil in the chamber. A filter portion is provided which has an opening through which fine particles contained in the pressure-receiving portion can pass, and which covers the open portion of the housing portion in which the pressure receiving portion is arranged. As a result, instead of trapping all the soil particles in the filter part as in the conventional method, the fine particles of the soil are passed through the filter part having openings through which the fine particles can pass. It is possible to suppress the clogging caused by adhering to the part. In addition, by providing the fluid supply unit for supplying fluid to the inside of the housing for the interstitial mud pressure gauge, even if the filter unit is clogged, the fluid supply unit supplies the fluid to the inside of the housing. Since the fluid can be supplied, it is possible to clean the filter section with the supplied fluid and eliminate the clogging of the filter section. As a result, the interstitial mud pressure gauge can continuously (repeatedly) measure the pressure caused by the moisture content of the soil in the chamber. The fine particles that pass through the filter section are in a state of floating in the interstitial water, so they have almost no effect on the values measured by the pressure-receiving section of the interstitial mud pressure gauge. In addition, by providing a soil pressure gauge, it is possible to acquire not only the pore mud pressure of the earth and sand in the chamber but also the soil pressure. can be estimated more appropriately.

In the above shield machine, the fluid supply unit is preferably configured to supply fluid having a viscosity higher than that of underground water (groundwater) contained in the ground to be excavated to the inside of the housing unit. It is With this configuration, the inside of the casing can be filled with a highly viscous fluid, so that soil water (groundwater) with low viscosity and soil particles including fine particles can enter the casing. can be suppressed.

In the above shield machine, preferably, the filter section is formed in a shape having an opening of 0.075 mm or more and 0.125 mm or less. With this configuration, fine particles can pass through the filter portion, and comparatively large soil particles that mainly bear the effective stress can be reliably captured by the filter portion.

The shield machine preferably further comprises a control unit that determines whether or not the mud additive is insufficient in the chamber based on the difference between the measured value of the soil pressure gauge and the measured value of the pore mud pressure gauge. With this configuration, it is possible to determine whether or not there is a shortage of the mud addition material in the chamber based on the difference between the measured value of the soil pressure gauge and the measured value of the pore mud pressure gauge. If it is determined that the soil is insufficient, it is possible to appropriately impart the required plastic fluidity and impermeability to the soil in the chamber by supplying the mud additive.

In this case, preferably, the control unit estimates the soil quality based on the difference between the measured value of the soil pressure gauge and the measured value of the pore mud water pressure gauge, so that the amount of mud added to the front side of the cutter head is insufficient. It is configured to determine whether or not there is With this configuration, it is possible to determine whether or not the mud addition material is insufficient in the chamber after estimating the soil quality, so it is possible to more appropriately determine whether or not the mud addition material is insufficient. can do. Therefore, the required plastic fluidity and water impermeability can be more appropriately imparted to the earth and sand in the chamber.

In the shield excavator, preferably, the soil pressure gauge and the pore mud pressure gauge are positioned near the center of the partition wall forming the chamber and near the earth and sand discharging device for discharging earth and sand from the chamber when viewed from the front in the excavation direction. are placed in at least one of the According to 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, the earth and sand are likely to stay because they are located on the inner peripheral side of the cutter head, and the mud addition material is removed. It is possible to measure the soil pressure and pore mud pressure in areas where there is a tendency to be insufficient. In addition, when the earth pressure gauge and the pore mud pressure gauge are arranged near the earth and sand discharge device that discharges earth and sand from the chamber, the earth and sand move rapidly by the earth and sand discharge device, and the state of plastic fluidity and water impermeability tends to change. It can measure soil pressure and pore mud pressure at the site.

In the method for measuring the sediment pressure of a shield machine according to the present invention, fine grains contained in the sediment in the chamber are detected by a pressure receiving portion inside a casing of a pore mud pressure gauge having a filter portion having an opening through which fine grains can pass. measuring the pore mud pressure due to moisture and moisture; measuring the soil pressure of the soil in the chamber with a soil pressure gauge; a step of judging whether or not there is a shortage of the mud additive in the chamber; and supplying fluid to the inside of the housing by the fluid supply section of the pore mud pressure gauge before measuring the pore mud pressure with the pore mud pressure gauge. and a step of.

In this earth and sand pressure measuring method for a shield machine, as described above, the pore mud water pressure gauge has an opening through which the fine particles contained in the earth and sand in the chamber can pass, and the pressure receiving portion is arranged inside. A filter section is provided to cover the opening of the housing section, and a step of measuring pore mud water pressure caused by fine particles and moisture contained in the earth and sand in the chamber by a pore water pressure gauge is provided. As a result, instead of trapping all the soil particles in the filter part as in the conventional method, the fine particles of the soil are passed through the filter part having openings through which the fine particles can pass. It is possible to suppress the clogging caused by adhering to the part. Further, by providing the step of supplying the fluid to the inside of the housing by the fluid supply unit, even if the filter unit is clogged, the fluid can be supplied to the inside of the housing by the fluid supply unit. Therefore, it is possible to wash the filter portion with the supplied fluid and eliminate the clogging of the filter portion. As a result, the interstitial mud pressure gauge can continuously (repeatedly) measure the pressure caused by the moisture content of the soil in the chamber. The fine particles that pass through the filter section are in a state of floating in the interstitial water, so they have almost no effect on the values measured by the pressure-receiving section of the interstitial mud pressure gauge. In addition, by providing the process of measuring the soil pressure with a soil pressure gauge, it is possible to acquire not only the pore mud pressure of the soil in the chamber, but also the soil pressure. Based on this, it becomes possible to estimate the soil quality in the chamber more appropriately.

According to the present invention, as described above, it is possible to continuously measure the pressure caused by the moisture content of the sediment in the chamber.

1 is a side cross-sectional view of a shield machine according to an embodiment; FIG. 1 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; FIG. FIG. 4 is a diagram for explaining the relationship between the particle size and type of soil particles; FIG. 2 is an enlarged side cross-sectional view of the pore mud pressure gauge according to the embodiment; It is the figure which expanded and showed the opening (mesh) of the pore mud water pressure gauge by embodiment. FIG. 4 is a diagram showing the relationship between the amount of silt added to a gravel layer and the sediment pressure measurement value; FIG. 4 is a diagram showing the relationship between the amount of mud additive injected into a clay layer and the sediment pressure measurement value;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

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

(Overall Configuration of Shield Machine)
A shield machine 100 shown in FIG. 1 is used for tunnel construction by the shield construction method. The shield machine 100 is a so-called mud pressure machine.

As shown in FIG. 1, a shield machine 100 includes a cutter head 1, a cylindrical body 2, a bulkhead 3, a chamber (mud chamber) 4, a propelling jack 5, a sand discharging device 6, and a It comprises a mud injection device 7 , an earth pressure gauge 8 and a pore mud pressure gauge 9 , and a control section 10 .

In each figure, the X direction indicates the front-rear direction of the shield machine 100, the X1 direction indicates the excavation direction (front) of the X directions, and the X2 direction indicates the opposite direction (rear) of the X direction.

In each figure, the vertical direction of the shield machine 100 is indicated by the Z direction, the upper direction in the Z direction is indicated by the Z1 direction, and the lower direction is indicated by the Z2 direction.

In each figure, the horizontal direction (width direction) of the shield machine 100 is indicated by the Y direction. Note that the Y direction is a direction orthogonal to both the X direction and the Z direction.

In each figure, the axis positioned at the center of rotation of the cutter head 1 is indicated by the center axis of rotation α.

The cutter head 1 is configured to move forward in the excavation direction as it rotates about the rotation center axis α extending in the excavation direction, thereby excavating the ground. The cutter head 1 is provided with a cutter driving portion 1a that imparts a rotational force around the rotation center axis α. The cutter drive unit 1a is configured by, for example, a hydraulic motor. The rotation of the cutter head 1 is configured to be switchable between normal rotation and reverse rotation according to the excavation situation or the like.

The body 2 is composed of a front body 2a and a rear body 2b. The front body portion 2a has a cutter head 1 installed at its front end in the excavation direction. The rear trunk portion 2b is a portion that advances while arranging the segments SG on the wall surface by an erector (not shown) in order to form the peripheral wall of the tunnel as the front trunk portion 2a is excavated. The internal space of the fuselage 2 is partitioned 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 .

The chamber 4 is a space in which earth and sand excavated by the cutter head 1 are stored. A chamber 4 is formed by the rear face of the cutter head 1 , the inner face of the barrel 2 and the front face of the partition wall 3 . That is, 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 equilibrium with the pressure acting on the cutter head 1 from the natural ground side by adjusting the amount of mud additive injected into the chamber 4 .

More specifically, in the mud pressure type shield machine 100, the mud additive is injected into the front side of the cutter head 1 by the mud additive injection device 7 and mixed with the excavated soil, thereby making the excavated soil impermeable. It is converted into mud having plastic fluidity and fills the chamber 4 . The shield machine 100 maintains a state in which the chamber 4 is filled with excavated earth and sand (mud), and generates mud pressure in the chamber 4 by the thrust of the propulsion jack 5, thereby reducing the pressure on the ground side (face soil). pressure and groundwater pressure). The shield excavator 100 excavates while maintaining pressure balance by balancing the amount of excavation and the amount of unloaded soil. In addition, when the mud additive injected by the mud additive injection device 7 is insufficient, the pressure is not properly balanced, and problems such as collapse of the ground and failure of the shield machine 100 occur. may be triggered.

Specifically, in a state of "insufficient mud-addition material", it is not possible to properly balance the mud pressure generated in the chamber 4 and the pressure on the side of the ground (earth pressure at the face and groundwater pressure). Therefore, landslides may occur. In addition, when the soil in the chamber 4 is not provided with the necessary water impermeability and plastic fluidity in the state of "insufficient mud addition material", the soil discharge device 6 may not properly discharge the soil. There is

Therefore, in order to suppress such a problem, the shield machine 100 (control unit 10) adds mud in the chamber 4 based on the difference between the measured value of the soil pressure gauge 8 and the measured value of the pore mud pressure gauge 9. It is configured to determine whether there is a shortage of materials. Details will be described later.

The propulsion jack 5 is configured to push the segment SG backward (X2 direction) to propel the shield machine 100 . A plurality of propelling jacks 5 are provided so as to line up along the circumferential direction of the body 2 .

The earth and sand discharging device 6 is composed of, for example, a screw conveyor. An opening 6 a at the front end of the earth and sand discharging device 6 communicates with the lower side of the chamber 4 . The earth and sand discharging device 6 is configured to take in earth and sand from inside the chamber 4 and discharge the earth and sand into the work space WS by rotating the internal screw 60 . The earth and sand discharged from the earth and sand discharging device 6 into the work space WS is conveyed toward the outside of the pit by an earth and sand conveying device (not shown) such as a belt conveyor.

The mud addition device 7 is configured to inject the mud addition material into the front side of the cutter head 1 . As an example, the mud additive is a material added to earth and sand containing bentonite as a main component. The mud filler injection device 7 includes a mud filler pipe 70 communicating with the front side of the cutter head 1 and a mud filler pump (not shown) for pumping the mud filler to the mud filler pipe 70 . contains. The mud addition device 7 is constructed so that the amount of mud added to the front side of the cutter head 1 can be freely adjusted.

(Structure of soil pressure gauge and pore mud pressure gauge)
As shown in FIG. 2, when one soil pressure gauge 8 and one pore mud pressure gauge 9 are set as one set, five sets of soil pressure gauges 8 and pore mud pressure gauges 9 are provided on the bulkhead 3 of the shield machine 100. there is

Each set of soil pressure gauge 8 and pore mud pressure gauge 9 is arranged at substantially the same height position. The earth pressure gauge 8 and the pore mud pressure gauge 9 of each set are arranged adjacent to each other in the left-right direction (Y direction) and are arranged in the vicinity of each other. As an example, the distance between the soil pressure gauge and the pore mud pressure gauge may be five times or less the diameter of the soil pressure gauge.

One set of the five sets of soil pressure gauges 8 and pore mud pressure gauges 9 is arranged near the center of the partition wall 3 when viewed from the excavation direction. “A position near the center of the partition wall 3 ” means either a central position of the partition wall 3 or a position slightly spaced from the central position of the partition wall 3 .

The other set of the five sets of soil pressure gauges 8 and pore mud pressure gauges 9 is arranged in the vicinity of an earth and sand discharging device 6 for discharging earth and sand from inside the chamber 4 when viewed from the excavation direction. The "position near the earth and sand discharger 6" means either a position adjacent to the opening 6a of the earth and sand discharger 6 or a position slightly spaced from the opening 6a. Specifically, the other set of the five sets of earth pressure gauges 8 and pore mud pressure gauges 9 is arranged below the opening 6 a of the earth and sand discharging device 6 .

The remaining three sets of the five sets of soil pressure gauges 8 and pore mud pressure gauges 9 are positioned directly above (in the Z1 direction) the center pair (soil pressure gauge 8 and pore mud pressure gauge 9) when viewed from the excavation direction. , and a set of positions on the right side of the center (the other in the Y direction).

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

The pore mud pressure gauge 9 is configured to measure the fine particle fraction P (see FIG. 5) contained in the earth and sand in the chamber 4 and the pore mud pressure caused by moisture (see FIG. 3). As an example, "fine particle fraction P" means soil particles having a particle size of less than 0.075 mm. In short, the "fine particle fraction P" is soil particles with a small particle size. In addition, soil particles having a particle size larger than the "fine particle fraction P" are referred to as "coarse particle fraction". The "coarse particle fraction" includes sand such as fine sand and gravel.

As shown in FIG. 4 , the pore mud pressure gauge 9 includes a housing portion 90 , a filter portion 91 , a pressure receiving portion 92 and a fluid supply portion 93 .

A housing portion 90 of the pore mud pressure gauge 9 is formed hollow. A pressure receiving portion 92 is arranged inside the housing portion 90 . An open portion 90a is provided at the front end portion of the housing portion 90 .

A filter portion 91 of the pore mud pressure gauge 9 is attached to the housing portion 90 so as to cover the open portion 90a. That is, the filter part 91 separates the interior space of the housing part 90 in which the pressure receiving part 92 is arranged from the inside of the chamber 4 . The filter portion 91 is formed in a mesh shape having openings (openings) 91a through which the fine particles P contained in the earth and sand in the chamber 4 can pass. As an example, the filter portion 91 is formed by weaving linear fibers in a grid. That is, the filter portion 91 is provided with a large number of rectangular openings (holes) 91a arranged in a matrix.

Although it is an example, the filter part 91 is formed in a mesh shape having an opening 91a of 0.075 mm or more and 0.125 mm or less. That is, the size L of one side of the rectangular opening (hole) 91a is 0.075 mm or more and 0.125 mm or less (see FIG. 5). Therefore, since the opening 91a of the filter portion 91 is larger than the fine particles P, it is possible to allow the fine particles P to pass through.

A pressure receiving portion 92 of the pore mud pressure gauge 9 is configured to receive pore mud pressure from the earth and sand in the chamber 4 . This is a pressure sensor that measures pore mud pressure. As an example, the pressure receiving unit 92 is configured to generate an electrical signal corresponding to the magnitude of the pore mud pressure and electrically measure the pore mud pressure. Note that the pressure receiving portion 92 may be configured to mechanically measure the interstitial mud water pressure.

Here, the so-called "pore water pressure gauge" is configured to prevent soil particles from entering the space where the pressure receiving part is arranged by means of a filter part having an extremely small opening, and to measure the pressure caused only by pure moisture. It is In the pore mud pressure gauge 9 of the present embodiment, the mesh opening 91a of the filter portion 91 is set to 0.075 mm or more and 0.125 mm or less, which is larger than the mesh opening of the "pore water pressure gauge".

Thus, the pore mud pressure gauge 9 of the present embodiment is configured to be able to measure not only the water content but also the pressure caused by the fine particle fraction P. In addition, the pore mud water pressure gauge 9 of the present embodiment purposely forms the filter portion 91 so that the fine particles P can pass through. This suppresses clogging of the filter portion 91 with the fine particles P and the like. Thus, the interstitial mud pressure gauge 9 has a structure in which the filter portion 91 is less likely to be clogged with soil particles.

The fine particles P passing through the filter section 91 are in a state of being suspended in interstitial water, so that the measurement by the pressure receiving section 92 is hardly affected. That is, if the pressure of soil in the chamber 4 is measured by the "pore water pressure gauge" and the pressure of the soil in the chamber 4 is measured by the pore pressure gauge 9, the measured value will be the same under the same measurement environment. almost never changes.

A fluid supply portion 93 of the pore mud pressure gauge 9 is provided in the housing portion 90 and configured to supply the fluid R to the inside of the housing portion 90 . The fluid supply unit 93 supplies the fluid R into the housing unit 90 before the interstitial mud pressure is measured by the interstitial mud pressure gauge 9 .

The fluid supply section 93 includes a fluid supply pipe 93a, a fluid storage section 93b, and a fluid supply pump 93c.

One end of the fluid supply pipe 93 a communicates with the interior of the housing portion 90 . The fluid storage portion 93b communicates with the other end of the fluid supply pipe 93a and stores the fluid R to be supplied to the inside of the housing portion 90 . The fluid supply pump 93c is configured to pump the fluid R into the housing portion 90 .

The fluid supply unit 93 is configured to supply, as the fluid R, a high-viscosity fluid R having a higher viscosity than underground water (groundwater) contained in the ground to be excavated into the housing unit 90. ing. By way of example, the “high-viscosity fluid R” is grease, a high-viscosity mud addition material (polymer-based mud addition material, highly water-absorbent resin-based mud addition material), or the like.

The fluid supply unit 93 is configured to supply the high-viscosity fluid R to the inside of the casing part 90 to fill the inside of the casing part 90 with the high-viscosity fluid R. As shown in FIG. When the high-viscosity fluid R fills the interior of the housing portion 90, water and fine particles P (see FIG. 5) enter the housing portion 90 from the chamber 4 through the filter portion 91. is suppressed. Further, when the high-viscosity fluid R is filled inside the housing part 90, the diffusion of the high-viscosity fluid R to the outside of the housing part 90 where there is underground water with low viscosity is suppressed, and the housing part 90 The high-viscosity fluid R can be retained inside.

The fluid supply unit 93 supplies the high-viscosity fluid R to the inside of the housing unit 90 to fill the inside of the housing unit 90 with the high-viscosity fluid R, and allows the high-viscosity fluid R to pass through the filter unit 91, thereby supplying the fluid R to the inside of the housing unit 90. The viscous fluid R is configured to flow out from the inside of the housing portion 90 toward the outside. Thus, the fluid supply unit 93 is configured to wash (backwash) the filter unit 91 with the highly viscous fluid R. As shown in FIG. As a result, relatively fine soil particles adhering to the filter portion 91 and relatively coarse soil particles clogging the filter portion 91 are removed from the filter portion 91 . Thus, the interstitial mud pressure gauge 9 has a configuration in which soil particles can be removed from the filter section 91 by the fluid supply section 93 .

Therefore, the interstitial mud pressure gauge 9 has a configuration in which the filter portion 91 is unlikely to be clogged with soil particles, and a configuration in which the fluid supply portion 93 can remove soil particles from the filter portion 91. It is possible to continuously and repeatedly perform highly accurate measurements even at

(Configuration of control section)
As an example, the control unit 10 shown in FIG. 1 is a circuit board including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

The control unit 10 is configured to determine whether or not there is a shortage of mud additive in the chamber 4 based on the difference (difference) between the measured value of the soil pressure gauge 8 and the measured value of the interstitial mud pressure gauge 9. ing. Specifically, the control unit 10 estimates the soil quality based on the difference (difference) between the measured value of the earth pressure gauge 8 and the measured value of the pore mud water pressure gauge 9, so that if there is a shortage of mud addition material in the chamber 4, It is configured to determine whether or not there is The control unit 10 is provided with an output device 10a for outputting a control result such as a lack of mud additive. Although it is an example, the output device 10a is configured by a display or the like.

Here, an example of the relationship between the measured value of the earth pressure gauge 8 and the measured value of the pore mud pressure gauge 9 and the injection of the mud additive into the chamber 4 will be described. In the explanation, the "gravel layer" composed of relatively coarse soil particles and the "clay layer" composed of relatively fine soil particles will be described in order. It should be noted that whether the ground is composed of a "gravel layer" or a "clay layer" is determined by a boring survey or the like performed prior to excavation by the shield machine 100. FIG. In the graphs of FIGS. 6 and 7, which will be described below, the horizontal axis indicates the mud additive content of the soil in the chamber 4, and the vertical axis indicates the measured value of the soil in the chamber 4 with the soil pressure gauge 8. It shows the ratio of the measured value of the interstitial mud pressure gauge 9 of the soil inside.

<Regarding the gravel layer>
First, the case of the "gravel layer" shown in FIG. 6 will be described. The ratio of the measured value of the pore mud pressure gauge 9 to the measured value of the soil pressure gauge 8 gradually increases as the mud addition material content increases. The ratio of the measured value of the interstitial mud pressure gauge 9 rapidly increases when the mud addition material content reaches A1. Furthermore, the ratio of the measured value of the pore mud pressure gauge 9 decreases again when the mud addition material content reaches A2, which is larger than A1.

The reason why the ratio of the measured value of the pore mud pressure gauge 9 to the measured value of the soil pressure gauge 8 fluctuates as described above is that below A1, most of the soil particles that make up the gravel layer are in contact with each other (contact state). On the other hand, at A2 or higher, many of the soil particles that make up the gravel layer float in the mud addition material and are separated from each other (floating state).

Therefore, at least when the content of the mud addition material is less than A2, particularly less than A1, the mud addition material is trapped between the soil particles constituting the gravel layer, and the face pressure is sufficiently reduced by the mud addition material. It can be said that it is not in a state where it can be propagated, but in a state where the mud addition material is insufficient. That is, it can be said that plastic fluidity and water impermeability are not sufficient at least when the mud addition material content is less than A2.

Although it is an example, the difference between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9 obtained by actual measurement is the measured value of the soil pressure gauge 8 at the threshold value T1 of the mud addition material. and the ratio of the value measured by the interstitial mud pressure gauge 9, it can be determined that the supply of the mud addition material into the chamber 4 is insufficient. Note that the threshold T1 is set to a predetermined value that is at least A2 or higher.

That is, the control unit 10 controls the difference between the ratio of the measured value of the earth pressure gauge 8 and the ratio of the measured value of the pore mud pressure gauge 9 obtained by actual measurement, and the ratio of the measured value of the earth pressure gauge 8 at the threshold value T1. and the ratio of the measured value of the pore mud water pressure gauge 9, and by estimating the soil quality, it is determined whether or not there is a shortage of the mud addition material in the chamber 4. there is

The determination by the control unit 10 using the threshold value T1 as described above is based on the accumulation of data on the measured values of the soil pressure gauge 8 and the pore mud pressure gauge 9 obtained by actual excavation by the shield machine 100. It will be possible to implement it for the first time. That is, the threshold value T1 can be set only by accumulating the data of the measured values of the soil pressure gauge 8 and the pore mud pressure gauge 9 .

Therefore, at least until the data is accumulated as described above, the control unit 10 is based on the time change of the difference (difference) between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud pressure gauge 9. It is configured to determine whether or not there is a shortage of the mud addition material in the chamber 4 by estimating the change in soil quality. As an example, "estimate soil change based on time change of the difference (difference) between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9", the shield machine 100 The difference (difference) between the ratio of the measured value of the earth pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9 fluctuates rapidly during the time change accompanying actual excavation. This includes estimating that there may be

<About the clay layer>
Next, the case of the "clay layer" shown in FIG. 7 will be described. The ratio of the measured value of the pore mud pressure gauge 9 to the measured value of the soil pressure gauge 8 gradually increases as the mud addition material content increases. Note that there is no inflection point where the ratio of the measured value of the pore mud water pressure gauge 9 to the measured value of the soil pressure gauge 8 fluctuates greatly, unlike the case of the "gravel layer". When the supply of the mud addition material is small, the plastic fluidity becomes low and the earth and sand become masses in a hard state with a high density. is smaller than that of the soil pressure gauge 8. On the other hand, when the mud addition material is sufficiently supplied, the plastic fluidity increases and the soil becomes a soft clay lump, so that the soil easily passes through the filter part 91 of the pore mud water pressure gauge 9, and the pore mud water pressure gauge 9 ratio of the measured value of

Although it is an example, the difference between the ratio of the measured value of the earth pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9 obtained by actual measurement is the measured value of the earth pressure gauge 8 at the threshold value T2 of the mud addition material. and the ratio of the value measured by the interstitial mud pressure gauge 9, it can be determined that the supply of the mud addition material into the chamber 4 is insufficient. The threshold value T2 is set to a predetermined value that is at least less than A3 of the mud additive. A3 is the mud addition material content when the ratio of the measured value of the earth pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9 are substantially equal.

That is, the control unit 10 controls the difference between the ratio of the measured value of the earth pressure gauge 8 and the ratio of the measured value of the pore mud pressure gauge 9 obtained by actual measurement, and the ratio of the measured value of the earth pressure gauge 8 at the threshold value T2. and the ratio of the measured value of the interstitial mud pressure gauge 9, and by estimating the soil quality, it is determined whether or not there is a shortage of the mud additive in the chamber 4. ing.

The determination by the control unit 10 using the threshold value T2 as described above is based on the accumulation of data on the measured values of the soil pressure gauge 8 and the pore mud pressure gauge 9 obtained by actual excavation by the shield machine 100. It will be possible to implement it for the first time. In other words, the threshold value T2 can be set only by accumulating the data of the measured values of the earth pressure gauge 8 and the pore mud pressure gauge 9 .

Therefore, at least until the data is accumulated as described above, the control unit 10 is based on the time change of the difference (difference) between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud pressure gauge 9. It is configured to determine whether or not there is a shortage of the mud addition material in the chamber 4 by estimating the change in soil quality. As an example, "estimate soil change based on time change of the difference (difference) between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9", the shield machine 100 The difference (difference) between the ratio of the measured value of the earth pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9 fluctuates rapidly during the time change accompanying actual excavation. This includes estimating that there may be

(Sediment pressure measurement method)
A sediment pressure measuring method by the shield machine 100 will be described. The sediment pressure measurement method includes the following steps.

In the sediment pressure measurement method, before the interstitial mud pressure is measured by the interstitial mud pressure gauge 9, a highly viscous fluid R is provided. As a result, the inside of the housing portion 90 is filled with the high-viscosity fluid R, and when soil particles adhere to the filter portion 91, the high-viscosity fluid R removes the soil particles from the filter portion 91. be This prepares the pore mud pressure gauge 9 for measurement.

In addition, the sediment pressure measurement method includes a pore mud water pressure gauge 9 having a mesh filter section 91 having mesh openings 91a through which fine particles P (see FIG. 5) contained in the sediment in the chamber 4 can pass. The pressure receiving unit 92 arranged inside the chamber 4 measures the fine particle fraction P contained in the earth and sand in the chamber 4 and the interstitial mud water pressure caused by moisture. At this time, the interstitial mud pressure gauge 9 measures not only the water contained in the earth and sand but also the pressure caused by the fine particle fraction P. Since the fine particle fraction P is particularly small among soil particles, Measurement by the pressure receiving section 92 is hardly affected. Measurement by the pore mud pressure gauge 9 is performed with the cutter head 1 stopped.

Moreover, the earth and sand pressure measuring method includes a step of measuring the earth pressure of the earth and sand in the chamber 4 by means of the earth pressure gauge 8 arranged near the interstitial mud pressure gauge 9 . The measurement by the soil pressure gauge 8 is usually performed at substantially the same timing as the measurement by the pore mud pressure gauge 9 . The measurement by the soil pressure gauge 8 is performed while the cutter head 1 is stopped.

In addition, the sediment pressure measuring method determines whether or not the mud additive is insufficient in the chamber 4 based on the difference (difference) between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9. It has a process of determining As a specific example, by estimating the soil change based on the time change of the difference (difference) between the ratio of the measured value of the soil pressure gauge 8 and the ratio of the measured value of the pore mud water pressure gauge 9, It is determined whether there is a shortage of materials. In addition, when there is accumulation of data on the measured values of the soil pressure gauge 8 and the measured values of the pore mud pressure gauge 9, a predetermined threshold value T1 or T2 is set for the mud addition material content rate, and the soil change is determined. By estimating, it is determined whether or not there is a shortage of mud additive to be supplied into the chamber 4 .

(Effect of Embodiment)
The following effects can be obtained in this embodiment.

In the present embodiment, as described above, the pore mud pressure gauge 9 for measuring the pore mud pressure caused by the fine grain fraction P and moisture contained in the soil in the chamber 4 is provided. A filter portion 91 is provided which has a mesh opening (opening) 91a through which the fine particles P contained in the earth and sand inside 4 can pass, and which covers an open portion 90a of a housing portion 90 in which a pressure receiving portion 92 is arranged. As a result, instead of trapping all soil particles in the filter portion 91 as in the conventional art, the fine particles P of earth and sand are allowed to pass through the filter portion 91 having openings 91a through which the fine particles P can pass. , the fine particles P can be prevented from adhering to the filter portion 91 and causing clogging. Further, by providing the fluid supply unit 93 for supplying the fluid R to the inside of the housing unit 90 for the pore mud water pressure gauge 9, even if the filter unit 91 is clogged, the fluid supply unit 93 can Since the fluid R can be supplied to the inside of the portion 90 , the filter portion 91 can be washed with the supplied fluid R to eliminate the clogging of the filter portion 91 . As a result, the interstitial mud pressure gauge 9 can continuously (repeatedly) measure the pressure caused by the water content of the earth and sand in the chamber 4 . Since the fine particles P passing through the filter portion 91 are in a state of floating in the pore water, they hardly affect the measured value by the pressure receiving portion 92 of the pore mud pressure gauge 9 . In addition, by providing the earth pressure gauge 8, it is possible to acquire not only the pore mud pressure of earth and sand in the chamber 4 but also the earth pressure. It is possible to more appropriately estimate the soil quality inside.

In the present embodiment, as described above, the fluid supply unit 93 supplies the fluid R having a higher viscosity than the underground water (groundwater) contained in the ground to be excavated into the housing unit 90 as the fluid R. configured to supply As a result, the high-viscosity fluid R can be filled inside the housing part 90, so that soil water (groundwater) with low viscosity and soil particles containing fine particles P enter the inside of the housing part 90. can be suppressed.

In this embodiment, as described above, the filter portion 91 is formed in a shape having an opening 91a of 0.075 mm or more and 0.125 mm or less. As a result, the fine particles P can pass through the filter portion 91, and the filter portion 91 can reliably capture relatively large soil particles that mainly bear the effective stress.

In this embodiment, as described above, based on the difference between the measured value of the earth pressure gauge 8 and the measured value of the pore mud water pressure gauge 9, the controller determines whether or not the mud addition material is insufficient in the chamber 4. 10. As a result, it is possible to determine whether or not there is a shortage of the mud addition material in the chamber 4 based on the difference between the measured value of the soil pressure gauge 8 and the measured value of the pore mud water pressure gauge 9. If it is determined that the sludge addition material is supplied, the required plastic fluidity and water impermeability can be appropriately imparted to the earth and sand in the chamber 4 .

In this embodiment, as described above, the control unit 10 supplies soil to the front side of the cutter head 1 by estimating the soil quality based on the difference between the measured value of the soil pressure gauge 8 and the measured value of the pore mud pressure gauge 9. It is configured to determine whether or not there is a shortage of mud addition material. As a result, it is possible to determine whether or not the mud addition material is insufficient in the chamber 4 after estimating the soil quality, so that it is possible to more appropriately determine whether or not the mud addition material is insufficient. can. Therefore, the required plastic fluidity and water impermeability can be more appropriately imparted to the earth and sand in the chamber 4 .

In the present embodiment, as described above, the earth pressure gauge 8 and the pore mud pressure gauge 9 discharge earth and sand from a position near the center of the partition wall 3 forming the chamber 4 and inside the chamber 4 when viewed from the front in the excavation direction. It is arranged at least one of the vicinity positions of the earth and sand discharging device 6 . As a result, when the soil pressure gauge 8 and the interstitial mud pressure gauge 9 are arranged near the center of the partition wall 3 forming the chamber 4, since they are located on the inner peripheral side of the cutter head, the soil tends to be retained, and the mud addition material is easily removed. It is possible to measure the soil pressure and pore mud pressure in areas where there is a tendency to be insufficient. Further, when the earth pressure gauge 8 and the interstitial mud water pressure gauge 9 are arranged in the vicinity of the earth and sand discharge device 6 for discharging the earth and sand from the chamber 4, the earth and sand move rapidly by the earth and sand discharge device 6, and the plastic fluidity and water impermeability are reduced. It is possible to measure the soil pressure and pore mud pressure in places where the condition of the soil is likely to change.

[Modification]
It should be noted that the embodiments and modifications disclosed this time should be considered as examples in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and includes all modifications (modifications) within the meaning and scope equivalent to the scope of the claims.

For example, in the above-described embodiment, the fluid supplied from the fluid supply unit is a high-viscosity fluid having a higher viscosity than the underground water contained in the ground to be excavated. is not limited to In the present invention, the fluid supplied from the fluid supply unit may be a fluid having a lower viscosity than underground water contained in the ground to be excavated.

Further, in the above-described embodiment, an example in which five sets of soil pressure gauges and pore mud pressure gauges are provided has been shown, but the present invention is not limited to this. In the present invention, 1 to 4 sets or 6 or more sets of soil pressure gauges and pore mud pressure gauges may be provided.

In addition, in the above-described embodiment, the mesh-like filter portion having openings is shown, but it may be a staggered filter portion, a honeycomb structure, or a structure such as punching metal. . The filter portion may not have a mesh shape as long as fine particles can pass through it.

Further, in the above-described embodiment, an example was shown in which the size of the opening of the filter portion was 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 mesh size of the filter portion may be set to a size other than 0.075 mm or more and 0.125 mm or less as long as fine particles can pass through.

Further, in the above-described embodiment, an example in which the mud addition material is supplied to the front side of the cutter head was shown, but the present invention is not limited to this. In the present invention, the mud addition material may be supplied directly into the chamber. In addition, the control unit estimates the soil quality based on the difference between the measured value of the soil pressure gauge and the measured value of the pore mud pressure gauge, and determines whether or not there is a shortage of the mud additive supplied to the chamber. good too.

The arrangement of the soil pressure gauge and the pore mud pressure gauge with respect to the partition wall shown in the above embodiment is only an example, and the soil pressure gauge and the pore mud pressure gauge may be arranged with respect to the partition wall at positions different from those in the above embodiment.

Further, in the above embodiment, an example in which the earth pressure gauge and the pore mud pressure gauge are provided on the partition wall has been shown, but the present invention is not limited to this. In the present invention, the soil pressure gauge and the pore mud pressure gauge may be provided on the inner peripheral surface of the body, the rear surface of the cutter head, or the like.

Further, in the above-described embodiment, an example is shown in which the shield machine includes a control unit that performs predetermined control based on the measured values of the soil 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 have to include the controller. In this case, the measured values of the soil pressure gauge and the pore mud pressure gauge are output as they are.

1 cutter head 3 partition wall 4 chamber 6 earth and sand discharger 8 soil pressure gauge 9 pore mud pressure gauge 10 control section 90 housing section 90a (of the housing section) open section 91 filter section 91a (of the pore mud pressure gauge) Opening (of pore mud water pressure gauge) 92 Pressure receiving portion (of pore mud water pressure gauge) 93 Fluid supply portion (of pore mud water pressure gauge) 100 Shield tunneling machine P Fine particle fraction R Fluid

Claims (7)

a chamber in which excavated earth and sand are stored;
a pore mud water pressure gauge for measuring pore mud water pressure caused by fine grain content and moisture contained in the earth and sand in the chamber;
and a soil pressure gauge that measures the soil pressure of the soil in the chamber,
The pore mud pressure gauge is
a pressure receiving portion that receives interstitial mud water pressure from earth and sand in the chamber;
a filter portion having an opening through which the fine particles contained in the earth and sand in the chamber can pass;
a housing portion provided with an open portion covered by the filter portion and having the pressure receiving portion disposed therein;
A shield machine comprising: a fluid supply unit provided in the housing and supplying a fluid to the inside of the housing. 2. The fluid supply unit according to claim 1, wherein the fluid supply unit is configured to supply, as the fluid, a fluid having a higher viscosity than underground water contained in the ground to be excavated into the housing unit. shield tunneling machine. 3. The shield machine according to claim 1, wherein said filter section is formed in a shape having an opening of 0.075 mm or more and 0.125 mm or less. 4. The method according to any one of claims 1 to 3, further comprising a control unit that determines whether or not there is a shortage of mud additive in the chamber based on the difference between the measured value of the soil pressure gauge and the measured value of the pore mud pressure gauge. A shield machine according to any one of claims 1 to 3. The control unit estimates the soil quality based on the difference between the measured value of the soil pressure gauge and the measured value of the pore mud water pressure gauge, thereby determining whether the mud addition material supplied to the front side of the cutter head is insufficient. 5. The shield machine according to claim 4, configured to determine whether or not. The soil pressure gauge and the pore mud pressure gauge are arranged at least one of a position near the center of the partition wall forming the chamber and a position near a sand discharging device for discharging soil from the chamber when viewed from the front in the excavation direction. The shield machine according to any one of claims 1 to 5, wherein The pore mud water pressure caused by the fine particles and moisture contained in the earth and sand in the chamber is measured by the pressure receiving part inside the housing part of the pore mud pressure gauge having a filter part having an opening through which the fine particles can pass. process and
measuring the earth pressure of earth and sand in the chamber with an earth pressure gauge;
a step of determining whether or not there is a shortage of mud additive in the chamber based on the difference between the measured value of the earth pressure gauge and the measured value of the pore mud pressure gauge;
and a step of supplying a fluid to the inside of the casing from a fluid supply unit of the pore mud pressure gauge before measuring the pore mud pressure by the pore mud pressure gauge.

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