Overexcavation filling method of shield tunneling machine equipped with ground exploration device

Abstract

To provide a shield tunneling machine with a ground exploration device using an ultrasonic sensor capable of improving the stability of the ground when drilling a hole in the ground.SOLUTION: When forming an excavation pit DP in the ground G by a slurry shield tunneling machine 1, the overexcavation area ES between the outer surface of the skin plates M1 and M2 of the slurry shield tunneling machine 1 and the inner surface of the excavation pit DP is filled with a ground retention material R discharged from the opening on the top surface of the cylindrical body 15c of a ground exploration device 15.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] The present invention relates to an overexcavation filling method for a shield tunneling machine equipped with a natural ground exploration device, for example, to an overexcavation filling method for filling an overexcavation section between the outer surface of the skin plate of a shield tunneling machine and the inner wall surface of an excavation tunnel. [Background technology]

[0002] When excavating the ground with a shield tunneling machine, if there is any significant loosening or cavity on the inner wall of the excavation tunnel directly above the shield tunneling machine, there is a risk of ground subsidence, etc. As a countermeasure, the condition of the inner wall of the ground is constantly measured and monitored using a ground exploration device, so that ground subsidence, etc. can be detected at an early stage and dealt with.

[0003] Such a ground exploration device is described, for example, in Patent Document 1, which discloses a technology for measuring the amount of overexcavation around a shield machine by emitting ultrasonic waves from an ultrasonic sensor arranged at the rear end of the nozzle in the spray direction into a water column formed by water sprayed toward the ground from the nozzle of a water flow generating device installed inside the shield machine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-134549 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when forming an excavation tunnel in the ground using a shield tunneling machine, if, for example, there is a sudden intake of excavated soil, the ground is soft, or a sharp curve is being constructed, excessive over-excavation may occur in the gap (over-excavation section) between the outer surface of the shield tunneling machine and the inner wall surface of the excavation tunnel, or the ground may become loose and unstable.

[0006] The present invention has been made in light of the above-mentioned technical background, and aims to provide a technology that can improve the stability of the ground when forming an excavation hole in the ground using a shield tunneling machine equipped with a ground exploration device using an ultrasonic sensor. [Means for solving the problem]

[0007] In order to solve the above problems, the method for filling overexcavation in a shield machine equipped with a natural ground exploration device of the present invention as described in claim 1 is characterized in that, when an excavation hole is formed in the ground by the shield machine equipped with a natural ground exploration device comprising: a through hole provided at the top of the skin plate of the shield machine, penetrating the inside and outside of the skin plate; a cylindrical body provided with the outer surface of its upper end connected to the inner surface of the through hole; an injection hole provided on the outer surface of the cylindrical body, penetrating the inside and outside of the cylindrical body; an injection piping connected to the injection hole; an injection pump that pressure-feeds ground retention material into the cylindrical body through the injection piping; a pressure detection means that detects the injection pressure inside the injection piping; a plate-shaped body attached to the lower end surface of the cylindrical body; and an ultrasonic sensor attached to the underside of the plate-shaped body, the overexcavation filling method comprises filling the overexcavation between the outer surface of the skin plate and the inner surface of the excavation hole with the natural ground retention material pressure-feeded into the cylindrical body.

[0008] The over-excavation filling method for a shield tunneling machine equipped with a ground exploration device of the present invention described in claim 2 is characterized in that, in the invention described in claim 1, the ground retention material released from a ground retention material injection section provided on the side of the skin plate of the shield tunneling machine is filled into the over-excavation section.

[0009] The over-excavation filling method for a shield tunneling machine equipped with a ground exploration device of the present invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2 above, the ground retention material is a mixture of bentonite, a polymer agent, and water. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the stability of the natural ground when an excavation hole is formed in the natural ground by a shield tunneling machine equipped with a natural ground exploration device using an ultrasonic sensor. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view of an earth pressure shield tunneling machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the cutter head of the earth pressure shield machine of FIG. 1. [Figure 3] This is a rear view of the partition plate of the mud pressure shield machine in Figure 1, looking at the position of line II from the direction of the arrow. [Figure 4] FIG. 2 is a plan view of the natural ground exploration device and its surroundings installed in the front body of the mud pressure shield machine of FIG. 1. [Figure 5] FIG. 5 is a side view of the natural ground exploration device of FIG. 4 and its surroundings. [Figure 6] FIG. 5 is a rear view of the natural ground exploration device and its surroundings in FIG. 4. [Figure 7] FIG. 7 is a partially cutaway enlarged rear view of the natural ground exploration device of FIG. 6. [Figure 8] FIG. 8 is a partially cutaway side view of the natural ground exploration device of FIG. 7. [Figure 9] 8(a) is a plan view of the natural ground exploration device of FIG. 7 as seen from above, and FIG. 8(b) is a plan view of the natural ground exploration device of FIG. 7 as seen from below. [Figure 10] FIG. 8 is a configuration diagram of a main part of a natural ground exploration system including the natural ground exploration device of FIG. 7. [Figure 11] 8 is a diagram summarizing the results of an experiment conducted by the inventors on the composition of materials constituting the natural ground retention material used in the natural ground exploration device of FIG. 7. [Figure 12] 8 is a diagram summarizing the results of an experiment conducted by the inventors on the composition of materials constituting the natural ground retention material used in the natural ground exploration device of FIG. 7. [Figure 13] 8 is a diagram summarizing the results of an experiment conducted by the inventors on the composition of materials constituting the natural ground retention material used in the natural ground exploration device of FIG. 7. [Figure 14]FIG. 8 is an enlarged, partially cutaway rear view of the natural ground exploration device of FIG. 7 during natural ground exploration. [Figure 15] FIG. 2 is a side view of the earth pressure shield machine during excavation. [Figure 16] This is a side view of the mud pressure shield machine during excavation, following Figure 15. [Figure 17] FIG. 8 is a schematic configuration diagram of an example of a supply system that supplies a natural ground holding material to the natural ground exploration device of FIG. 7. [Figure 18] 18(a) is a plan view of the upper surface of a cylindrical body constituting the natural ground exploration device of FIG. 7, and FIG. 18(b) is an enlarged cross-sectional view of a main part taken along line II-II of FIG. 18(a). [Figure 19] 19(a) is a plan view of a modified example of a grid member provided on the upper surface of a cylindrical body constituting the natural ground exploration device of FIG. 7, and FIG. 19(b) is a plan view showing the function of the grid member of FIG. 19(a). [Figure 20] 8 is a plan view of a modified example of a grid member provided on the upper surface of a cylindrical body that constitutes the natural ground exploration device of FIG. 7. FIG. [Figure 21] 21(a) is a plan view of a modified example of a grid member provided on the upper surface of a cylindrical body constituting the natural ground exploration device of FIG. 7, and FIG. 21(b) is an enlarged cross-sectional view of a main part taken along line III-III of FIG. 21(a). [Figure 22] FIG. 2 is a plan view of the earth pressure shield machine of FIG. 1 as seen from above. [Figure 23] 23 is a cross-sectional view taken along line IV-IV in FIG. 22. [Figure 24] FIG. 24 is an enlarged cross-sectional view of a main part of the earth pressure shield machine of FIG. 23. [Figure 25] FIG. 23 is a cross-sectional view taken along line IV-IV in FIG. 22, illustrating a modified example of the method for filling the extra trench. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally designated by the same reference numerals, and repeated description thereof will be omitted.

[0013] (First embodiment)

[0014] Figure 1 is a side view of the mud shield machine of this embodiment, Figure 2 is a front view of the cutter head of the mud shield machine of Figure 1, and Figure 3 is a rear view of the partition plate of the mud shield machine of Figure 1, looking from the direction of the arrow at the position of line II. Note that for the purpose of explanation, the interior of the mud shield machine 1 is shown as a see-through view in Figure 1.

[0015] The mud pressure shield tunneling machine 1 of this embodiment shown in Figures 1 to 3 is an excavation machine that fills the chamber 4 between the cutter head 2 and the equipment body 3 with soil excavated by the cutter head 2, and then injects and mixes the soil to turn it into mud with high plastic fluidity (the ability to deform and move freely), and uses the resulting earth pressure to construct an excavation tunnel while stabilizing the face.

[0016] Although not particularly limited, the diameter of the cutter head 2 of the mud pressure shield machine 1 is, for example, about 4070 mm, and the length of the mud pressure shield machine 1 is, for example, about 9170 mm.

[0017] 1 and 2, the cutter head 2 is an excavation machine that excavates the face of the natural ground. The cutter head 2 is formed, for example, in a circular shape when viewed from the front, and is installed in front of the equipment body 3 in a state in which it can rotate freely in both forward and reverse directions along the circumferential direction of the cutter head 2.

[0018] The cutter head 2 is configured, for example, as a spoke-type cutter head. That is, as shown in Fig. 2, the cutter head 2 includes a hub portion 2H in the center of the excavation surface (the surface facing the cutting face), an outer peripheral ring portion 2R provided so as to surround the outer periphery of the hub portion 2H, four spoke portions 2S provided between the hub portion 2H and the outer peripheral ring portion 2R, face plate portions 2F provided between adjacent ones of the four spoke portions 2S, and an opening portion 2A provided between the spoke portion 2S and the face plate portion 2F.

[0019] A bit 5a called a center bit and an additive injection section 7a are installed on the hub section 2H of the cutter head 2. In place of the center bit, other excavation members such as a cone head type roller bit may be installed.

[0020] The additive injector 7a is an injector that injects a soil-making material, such as a bentonite-based additive, toward the face in front of the cutter head 2. Note that the additive injected from the additive injector 7a may be an aerated material instead of a bentonite-based additive, or both a bentonite-based additive and an aerated material may be used.

[0021] A plurality of bits 5b called outer bits are mounted on the front surface (the surface facing the working face) of the outer ring portion 2R of the cutter head 2. In addition, two bits 5c called copy cutters are mounted on the outer peripheral surface (the surface facing the inner peripheral surface of the excavation hole) of the outer ring portion 2R, positioned opposite each other. These bits 5c have functions such as over-excavation when constructing sharp curves and controlling the attitude of the earth pressure shield machine 1.

[0022] The spokes 2S of the cutter head 2 are made up of four frame members that connect the hub 2H and the outer ring 2R. This arrangement of the spokes 2S allows the aperture ratio of the opening 2A to be increased, allowing gravel to be taken into the chamber 4 without breaking it as much as possible.

[0023] In addition, the aperture ratio of the opening 2A can be adjusted by installing a face plate portion 2F between adjacent spoke portions 2S. This face plate portion 2F is fixed to the outer peripheral ring portion 2FR and is also fixed to the hub portion 2H by a connecting rod portion 2FR.

[0024] At the center of the width direction (circumferential direction of the cutter head 2) on the front surface (surface facing the cutting face) of the spoke portion 2S and the face plate portion 2F, multiple bits 5d called leading bits are installed along the radial direction of the cutter head 2 (direction from the center of the front surface of the cutter head 2 toward the outer periphery).

[0025] In addition, a plurality of scraper teeth 6 are provided along the edges of the front of each spoke portion 2S at both ends in the width direction. In addition to the bit 5d, other excavation members such as roller bits may also be provided on the spoke portion 2S.

[0026] In addition, an additive injection section 7b is provided in the spoke portion 2S. The additive injected from this additive injection section 7b is, for example, the same as that described for the additive injection section 7a above. This additive injection section 7b may be arranged on a different rotational trajectory within the front of the cutter head 2. This allows for more diversified control of the injection of additive, thereby enabling more accurate and efficient plastic fluidization of the excavated soil. Note that the additive injected from the additive injection section 7b may be an aerated material instead of a bentonite-based additive, or both a bentonite-based additive and an aerated material may be used.

[0027] As shown in FIG. 1, the device body 3 includes a front body section 3a, a rear body section 3b provided behind the front body section 3a, and a tail seal section 3c provided at the rear end of the rear body section 3b.

[0028] The forward section 3a and the aft section 3b are equipped with cylindrical skin plates M1, M2 made of, for example, steel. The skin plates M1, M2 are hollow exterior bodies that form the outer shape of the equipment main body 3 and also form a hollow space for installing equipment and the like inside the equipment main body 3. The forward section 3a and the aft section 3b are engaged with each other by inserting the tip of the skin plate M2 into the skin plate M1 while it is in contact with the inner circumferential surface of the skin plate M1.

[0029] A bulkhead plate 8 is provided on the front side of the skin plate M1 of the forward body section 3a, at a position set back from the front surface inward of the equipment main body 3, dividing the hollow space within the equipment main body 3 into a face side and an inboard side. The chamber 4 is provided closer to the face than the bulkhead plate 8 (i.e., in the space between the cutter head 2 and the bulkhead plate 8).

[0030] 1 and 3, fixed blades 9a are provided in a fixed state on the front surface (chamber 4 side) of partition plate 8. Fixed blades 9a are provided in a state of protruding from the front surface of partition plate 8 toward chamber 4.

[0031] 1 and 2, stirring blades 9b are fixed to the back surface of the spokes 2Sa of the cutter head 2. The stirring blades 9b are provided in a state of protruding from the back surface of the cutter head 2 toward the chamber 4, and rotate as the cutter head 2 rotates.

[0032] The fixed blades 9a and the stirring blades 9b are members that mix, stir, and knead the soil, sand, additives, and water inside the chamber 4 when the cutter head 2 rotates. Note that the fixed blades 9a may be configured to inject additives from the tip thereof.

[0033] As shown in Figure 1, the tail seal portion 3c is a water-stopping mechanism that prevents groundwater, backfill material, etc. from flowing into the inside of the equipment main body 3, and is installed along the circumferential direction of the skin plate M2 with the front end side of the tail seal portion 3c joined to the inner surface of the rear end part of the skin plate M2.

[0034] The rear end of the tail seal 3c is in close contact with the outer circumferential surface of the segment SG. In addition, the tail seal 3c itself and the rear end of the tail seal 3c that is in close contact with the segment SG are constantly supplied with a filler (tail grease). This maintains the waterproofing performance.

[0035] Here, an example is shown in which a double sealing member of the tail seal portion 3c is installed along the axial direction (excavation direction) of the equipment main body 3, but the installation configuration of the sealing member is not limited to double, and may be, for example, single, or triple or more.

[0036] On the other hand, as shown in Figures 1 and 3, in the mud pressure shield machine 1, on the inside of the machine rather than the partition plate 8, there are installed an additive injection section 7c, an earth pressure gauge 10 (see Figure 3), a cutter driver 11, a center bending jack 12a, a shield jack 12b, a screw conveyor 13, an erector 14 (see Figure 1), and a ground exploration device 15 (see Figure 1), etc.

[0037] The additive injecting section 7c is an injecting section that injects an additive into the outer periphery of the device body 3. The additive injected from this additive injecting section 7c is, for example, the same as that described above for the additive injecting sections 7a and 7b.

[0038] The earth pressure gauge 10 is a sensor that detects the pressure caused by the mud inside the chamber 4, and is installed with its detection surface facing the inside of the chamber 4. This earth pressure gauge 10 measures the mud pressure inside the chamber 4, and by controlling the measured value so that it falls within a predetermined range, it is possible to proceed with the excavation process while ensuring the stability of the face.

[0039] The cutter drivers 11 are drive sources for rotating the cutter head 2, and a plurality of them are arranged in a line along the circumferential direction of the cutter head 2 between the center and the outer periphery of the front surface of the cutter head 2. Note that an intermediate support drive system is exemplified here as the cutter drive system.

[0040] The articulating jacks 12a are devices that correct the advancing direction of the earth shield machine 1 by bending the machine, and multiple jacks are installed in a line along the circumferential direction of the earth shield machine 1 inside the main body 3. By supplying pressure oil to these articulating jacks 12a and advancing the earth shield machine 1 with the front body 3a and rear body 3b bent in a predetermined direction and angle, it is possible to control the advancing direction of the earth shield machine 1.

[0041] The shield jack 12b is a device that generates a propulsion force to advance the mud pressure shield machine 1 by receiving a reaction force from the segment SG installed at the rear of the equipment main body 3, and multiple shield jacks are arranged in a row along the circumferential direction of the mud pressure shield machine 1 within the equipment main body 3.

[0042] The screw conveyor 13 is a device for discharging the soil and sand taken into the chamber 4 to the outside of the machine, and is provided so as to penetrate the partition plate 8 from the chamber 4 and extend continuously diagonally upward toward the rear of the machine body 3. Here, for example, a ribbon-type screw conveyor 13 is used. That is, a spiral blade 13B without a rotation axis is installed in the pipe of the screw conveyor 13 in a freely rotatable state.

[0043] The erector 14 is an assembly device that grasps the segment SG, rotates it in the inner circumferential direction of the borehole, and transports and installs it to an assembly position in the inner circumferential direction of the borehole.It is installed in the hollow of the skin plate M2 of the rear body section 3b in a state that allows it to rotate in the circumferential direction of the borehole by a hydraulic motor (not shown) for driving the erector, etc.

[0044] The natural ground exploration device 15 is a device that uses an ultrasonic sensor to continuously and non-contactly explore the condition of the inner wall surface of the natural ground directly above the top of the skin plate M1 of the mud shield machine 1 while the mud shield machine 1 is excavating. Here, an example of the configuration of the natural ground exploration device 15 of this embodiment will be described with reference to Figs. 4 to 10.

[0045] Figure 4 is a plan view of the natural ground exploration device and its surroundings installed in the front barrel of the earth pressure shield machine of Figure 1, Figure 5 is a side view of the natural ground exploration device of Figure 4 and its surroundings, and Figure 6 is a rear view of the natural ground exploration device of Figure 4 and its surroundings. For the purpose of explanation, the inside of the front barrel of the earth pressure shield machine 1 is shown as a see-through view in Figures 4 to 6.

[0046] As shown in Figures 4 and 5, the ground exploration device 15 is installed between the front end of the skin plate M1 and the ground collapse exploration device 16, and as shown in Figures 4 and 6, it is installed in the widthwise center of the front body 3a (between the two additive material injection sections 7c, 7c).

[0047] As shown in Figure 5, although not particularly limited, the distance L1 from the front end of the skin plate M1 to the center of the natural ground exploration device 15 is, for example, approximately 1050 mm, and the distance L2 from the front end of the skin plate M1 to the center of the natural ground collapse exploration device 16 is, for example, approximately 1700 mm.

[0048] Figure 7 is a partially cutaway enlarged rear view of the natural ground exploration device of Figure 6, Figure 8 is a partially cutaway side view of the natural ground exploration device of Figure 7, Figure 9(a) is a plan view of the natural ground exploration device of Figure 7 seen from above, Figure 9(b) is a plan view of the natural ground exploration device of Figure 7 seen from below, and Figure 10 is a diagram of the main components of a natural ground exploration system equipped with the natural ground exploration device of Figure 7.

[0049] 7 and 8, the natural ground exploration device 15 is installed at a position slightly set back inward from the top of the skin plate M1 of the earth pressure shield machine 1. A through hole 15h is drilled at the top of this skin plate M1, penetrating between the outer and inner peripheral surfaces of the skin plate M1. The through hole 15h is formed, for example, in a circular shape in plan view.

[0050] Although not particularly limited, the diameter Φ1 (see FIG. 8) of the through hole 15h is, for example, about 165.2 mm, and the thickness T1 (see FIG. 8) of the skin plate M1 is, for example, about 36 mm.

[0051] In the skin plate M1, a cylindrical body 15c is joined to the location where the through hole 15h is formed, with the outer peripheral surface of the upper end of the cylindrical body 15c being in contact with the inner peripheral surface of the through hole 15h. As shown in Figures 7 to 9(a), the cylindrical body 15c is, for example, Cylindrical steel The upper surface of the housing is open.

[0052] The diameter of the cylindrical body 15c is the same as the diameter Φ1 of the through-hole 15h. Although not particularly limited, the height H1 (see FIG. 8) of the cylindrical body 15c is, for example, about 230 mm.

[0053] The cylindrical body 15c is disposed at the center of the upper surface of the plate-like body 15p. As shown in Fig. 9(a), the plate-like body 15p is formed, for example, in a circular shape in a plan view, but is formed with a larger diameter than the cylindrical body 15c.

[0054] Although not particularly limited, the diameter Φ2 (see FIG. 8) of the plate-like body 15p is, for example, about 2485 mm, and the height H2 (see FIG. 8) from the top of the skin plate M1 to the underside of the plate-like body 15p is, for example, about 258 mm. The cross section of this cylindrical body 15c is not limited to a circular shape, and may be rectangular, etc.

[0055] The plate-like body 15p is made of a material that transmits ultrasonic waves. If the plate-like body 15p were made of steel, it would not transmit ultrasonic waves, so in this embodiment, the plate-like body 15p is made of a resin such as monomer cast nylon (polyamide 6).

[0056] However, even if the plate-like body 15p is made of resin, if the plate-like body 15p is too thick, the ultrasonic waves will be greatly attenuated and the sensor sensitivity will be significantly reduced, while if the plate-like body 15p is too thin, it will not be able to withstand the earth pressure.

[0057] Therefore, in this embodiment, the thickness T2 of the plate-like body 15p (see Figure 8) is set to, for example, about 30 mm, which is a thickness that does not significantly attenuate ultrasonic waves, has strength equal to or greater than that of the skin plate M1, and can withstand earth pressure.

[0058] 7 and 8, a frame 15f, which is, for example, a circular frame in a plan view, is installed on the upper surface of the plate-like body 15p. The frame 15f and the plate-like body 15p are formed to have the same diameter, and are fastened together in a detachable manner with their outer peripheries aligned in a plan view by a plurality of bolts 15b and nuts 15n arranged near their outer peripheries. The lower end of the cylindrical body 15c is fitted into the frame 15f, and the plate-like body 15p is thereby attached to the lower end surface of the cylindrical body 15c.

[0059] Furthermore, an injection hole 15ih is drilled in the side surface of the cylindrical body 15c, penetrating between the outer and inner surfaces of the cylindrical body 15c, and an injection pipe 15ip is mechanically connected to the injection hole 15ih.

[0060] Then, the inside of the cylindrical body 15c is filled with ground retention material through this injection pipe 15ip. This ground retention material is made of a material that easily propagates ultrasonic waves (a medium for ultrasonic wave propagation). This allows ultrasonic waves to be propagated well through the ground retention material inside the cylindrical body 15c. An example of the configuration of this ground retention material will be described later.

[0061] Although not particularly limited, height H3 (see FIG. 8) from the top of skin plate M1 to the center of injection hole 15ih is, for example, about 130 mm.

[0062] 7 and 10, a pressure sensor 15ps is mechanically connected to the injection pipe 15ip in the extending direction via an on-off valve 15v1. This pressure sensor 15ps is a pressure detection means that detects the pressure inside the injection pipe 15ip, converts it into an electrical signal, and outputs it, and as shown in Fig. 10, is electrically connected to a pressure measuring instrument PM via a cable C1.

[0063] The pressure measuring device PM is a device that measures the injection pressure inside the injection pipe 15ip based on the electrical signal sent from the pressure sensor 15ps, and is electrically connected to the control unit MC via a cable C2. The pressure measuring device PM and the control unit MC are installed on a trailing carriage (not shown) behind the mud pressure shield machine 1.

[0064] 7 and 10, a pressure relief valve 15v2 is mechanically connected between pressure sensor 15ps and cylindrical body 15c midway along the extension direction of injection pipe 15ip. This pressure relief valve 15v2 automatically releases air from inside injection pipe 15ip. This pressure relief valve 15v2 ensures stability of the pressure inside cylindrical body 15c.

[0065] 7 and 10, the injection pipe 15ip is mechanically connected to a supply pipe SP1 (see FIG. 10) via a swing valve 15v3 and a ball valve 15v4, in that order from the side closest to the cylindrical body 15c. This supply pipe SP1 is mechanically connected to a ground-holding material supply section RS via an injection pump 15pp.

[0066] As shown in Figure 10, injection pump 15pp is a device that pumps the ground retention material supplied from ground retention material supply unit RS into the inside of cylindrical body 15c, and the drive motor 15ppm of injection pump 15pp is electrically connected to control unit MC via cable C3. Note that injection pump 15pp and ground retention material supply unit RS are installed on a trailing bogie behind the mud pressure shield machine 1.

[0067] In this embodiment, the control unit MC automatically controls the drive motor 15ppm of the injection pump 15pp based on the measurement data of the injection pressure inside the injection pipe 15ip sent from the pressure measuring instrument PM so that the pressure inside the cylindrical body 15c is always at a predetermined pressure.

[0068] Here, the predetermined pressure is set to, for example, a pressure equal to or greater than the earth pressure at the face. This earth pressure at the face refers to the earth pressure in front of the cutter head 2 and the earth pressure inside the chamber 4. In the case of a mud shield, this earth pressure at the face corresponds to the face water pressure. This makes it possible to constantly maintain the pressure inside the cylindrical body 15c at or above the earth pressure at the face, thereby maintaining the stability of the ground above the mud shield machine 1. This therefore improves the safety of ground excavation work using the mud shield machine 1.

[0069] As shown in Figures 7 to 9(b), an ultrasonic sensor 15ss is attached to the underside of the plate-like body 15p. The ultrasonic sensor 15ss is an ultrasonic detection means that emits ultrasonic waves from a sensor head and receives the ultrasonic waves reflected from the inner wall surface of the natural ground facing the natural ground exploration device 15 again with the sensor head.

[0070] As shown in Figure 10, the ultrasonic sensor 15ss is electrically connected to a distance measuring device LM via a cable C4. The distance measuring device LM is an instrument that measures the distance from the top of the skin plate M1 to the inner wall surface of the opposing ground G by measuring the time between the transmission and reception of ultrasonic waves, and is electrically connected to the control unit MC via a cable C5. The distance measuring device LM is installed on the trailing bogie behind the mud pressure shield machine 1.

[0071] The control unit MC is electrically connected to the monitor MD via a cable C6, and creates a visible image of the ground based on the distance measurement data sent from the distance measuring device PM, and displays this image on the monitor MD. This allows the operator to grasp the condition of the inner wall surface of the ground above the mud pressure shield machine 1 in real time.

[0072] The ultrasonic sensor 15ss uses a frequency band of, for example, 400 kHz, which allows detection within a range of several meters. This ultrasonic sensor 15ss cannot receive reflected waves for a certain period of time due to the influence of reverberation vibrations after generating sound waves, and there is an unmeasurable range (for example, a close range of about 0 to 30 cm) where measurement is not possible. Note that the frequency band of the ultrasonic sensor 15ss is not limited to 400 kHz, and other frequency bands can be used.

[0073] In this embodiment, the measurement range of the natural ground exploration is within a range of several meters from the top of the skin plate M1, so the position of the ultrasonic sensor 15ss is set back to allow for a margin into the non-measurable range. In other words, the height of the ultrasonic sensor 15ss is set back below the top of the skin plate M1.

[0074] This allows the ultrasonic sensor 15ss to constantly measure and monitor the condition of the inner wall surface of the ground G directly above the top of the skin plate M1 of the earth pressure shield machine 1, making it possible to detect and deal with problems such as ground subsidence early.This prevents the ground from collapsing and subsidence due to the sudden intake of excavated soil by the earth pressure shield machine 1, improving the safety of ground excavation work.

[0075] Furthermore, by installing the ultrasonic sensor 15ss directly below the cylindrical body 15c, the natural ground exploration device 15 can be made smaller than when the ultrasonic sensor 15ss is installed offset laterally from the cylindrical body 15c.

[0076] Next, examples of the configuration of the above-mentioned ground holding material will be described with reference to Figures 11 to 13. Figures 11 to 13 are diagrams summarizing the results of experiments conducted by the inventors on the blending of materials constituting the ground holding material used in the ground exploration device of Figure 7.

[0077] The ground retention material filled inside the cylindrical body 15c is the additive (such as the bentonite mentioned above) used in the mud pressure shield machine 1. This additive generally contains mineral-based materials, which contain a large amount of particles. If the particle concentration in the additive becomes too high, ultrasonic waves are scattered and exploration becomes impossible.

[0078] Therefore, the inventors prepared a ground retention material using a mixture of, for example, bentonite, a polymer agent, and water, and determined whether the composition of the constituent materials was good or bad by observing the state of ultrasonic wave propagation and the state of viscosity of the ground retention material when the composition of the constituent materials was changed.

[0079] As a result, as shown in Figures 11 and 12, when the amount of bentonite was 80 kg / m 3 It was found that when the amount of bentonite is 30 kg / m, the concentration of bentonite becomes too high to allow the ultrasonic waves to pass through, making it impossible to measure the ultrasonic waves. 3 It was found that when the amount of bentonite is too low, it cannot react with the polymer agent and the viscosity is insufficient. 3 was found to be suitable.

[0080] On the other hand, as shown in Figure 12, when the amount of polymer agent was 0.4 L / m 3 At 0.5L / m, it was found that there was not enough polymer and the viscosity of the ground retention material was insufficient. 3 When the amount of polymer was 9.0 L / m, it was found that the viscosity of the ground retention material was insufficient. 3 When the amount of polymer was 2.0 L / m, it was found that the amount of polymer was too high and the viscosity was too high to pump. 3 It was found that the amount of polymer agent was 0.65 to 1.0 L / m 3 was found to be suitable.

[0081] Therefore, as shown in FIG. 12, in this embodiment, the amount of bentonite with a large particle content is set to 40 kg / m as the blending ratio of the ground retention material. 3 More than 60kg / m 3 The amount of polymer agent is 0.50 L / m or less. 3 More than 2.0L / m 3 Less than or equal to 0.65 L / m 3 More than 1.00L / m 3 As a result, the condition of the inner wall surface of the ground can be properly detected by the ultrasonic sensor 15ss while supporting the ground directly above the top of the skin plate M1 of the mud pressure shield machine 1.

[0082] The ground retention material used here was produced by mixing bentonite containing, for example, SiO2, Al2O3, FeO3, CaO, MgO, KO and NaO, a polymer agent containing, for example, acrylic resin, paraffin oil and surfactant, and water.

[0083] In addition, the ground retention material was produced by mixing water with an auxiliary material made by mixing the above bentonite with a polymer material such as CMC (carboxymethyl cellulose).

[0084] Next, an example of a natural ground exploration method using the mud pressure shield machine 1 in this embodiment will be described with reference to Figures 14 to 16. Figure 14 is an enlarged, partially cutaway rear view of the natural ground exploration device of Figure 7 during natural ground exploration. For the purpose of explanation, Figure 14 shows the inside of the cylindrical body 15c of the natural ground exploration device 15 in a see-through manner.

[0085] First, as shown in Figure 14, during natural ground exploration, the natural ground retention material R is continuously pumped and filled into the inside of the cylindrical body 15c through the injection pipe 15ip of the natural ground exploration device 15. During this process, the pressure inside the cylindrical body 15c is maintained at a predetermined pressure (e.g., earth pressure at the face) or higher based on the pressure measurement value from the pressure sensor 15ps as described above. This makes it possible to constantly maintain the stability of the natural ground G above the mud shield machine 1. This prevents the collapse of the natural ground and subsidence caused by the sudden intake of excavated soil by the mud shield machine 1, thereby improving the safety of natural ground excavation work using the mud shield machine 1.

[0086] Next, ultrasonic waves US are emitted from the sensor head of ultrasonic sensor 15ss toward the inner wall surface of the ground G facing the natural ground exploration device 15, and the ultrasonic waves reflected from the inner wall surface of the ground G are received again by the sensor head of ultrasonic sensor 15ss, and the distance from the top of the skin plate M1 of the mud pressure shield machine 1 to the inner wall surface of the ground G facing that top is measured based on the time between transmission and reception of the ultrasonic waves. In this way, the condition of the inner wall surface of the ground G facing the natural ground exploration device 15 is explored without contact.

[0087] Next, Figures 15 and 16 are side views of the earth pressure shield machine during excavation. Note that Figures 15 and 16 show positions X1 to X3 of the earth pressure shield machine 1. Furthermore, symbol USs indicates ultrasonic waves emitted from ultrasonic sensor 15ss, and USr indicates ultrasonic waves reflected from the natural ground G.

[0088] First, as shown in Figure 15, an excavation hole is formed in the ground G by the excavation operation of the earth pressure shield machine 1. At this time, the ground exploration device 15 of the earth pressure shield machine 1 is operated as described in Figure 14 to continuously measure the distance from the top of the skin plate M1 of the earth pressure shield machine 1 to the inner wall surface of the ground G facing that top.

[0089] Next, as shown in Figure 16, the excavation operation of the mud shield machine 1 continues to excavate the excavation hole. At this time, in this embodiment, the excavation operation of the mud shield machine 1 is continued without stopping, and the natural ground exploration device 15 also continues to operate, thereby continuously measuring the distance from the top of the skin plate M1 of the mud shield machine 1 to the inner wall surface of the natural ground G facing that top.

[0090] This makes it possible to visually check (understand) in real time through the monitor MD of the mud shield machine 1 whether there are cavities above the mud shield machine 1, allowing problems such as ground subsidence to be discovered early and dealt with promptly. This therefore improves the safety of excavation work using the mud shield machine 1.

[0091] In this embodiment, as shown in Figure 16, hollow portion CA in the natural ground G can also be filled with natural ground retention material R discharged from the cylindrical body 15c of the natural ground exploration device 15. This makes it possible to explore the natural ground above the earth pressure shield machine 1 while suppressing or preventing problems such as subsidence of the natural ground, thereby further improving the safety of excavation work by the earth pressure shield machine 1.

[0092] (Ground retention material supply system and supply method)

[0093] Next, an example of a supply system for supplying ground holding material to the ground exploration device of this embodiment will be described with reference to Fig. 17. Fig. 17 is a schematic configuration diagram of an example of a supply system for supplying ground holding material to the ground exploration device of Fig. 7.

[0094] The additive supply unit AS constituting the ground retention material supply system of this embodiment is a supply unit that generates and supplies an additive made of, for example, a mixture of bentonite and water, and is installed in an above-ground plant.

[0095] This additive supply unit AS is part of an additive supply system that supplies additive to the additive injection units 7a to 7c (see Figure 1, etc.) of the mud pressure shield machine 1, and is mechanically connected to the additive injection unit 7b of the cutter head 2 via a supply pipe SP2. A supply pump PP1 is mechanically interposed at the starting end of this supply pipe SP2, and is configured to pressure-feed the additive from the additive supply unit AS to the additive injection unit 7b.

[0096] The additive supply section AS is mechanically connected to a flow path switching section (flow path switching means) LC through a supply pipe SP3. This flow path switching section LC is provided with automatic switching valves (flow path switching means) V1, V2 that automatically switch the flow path of the additive sent through the supply pipe SP3 to either the additive injection section 7a or the ground retention material supply section RS.

[0097] That is, supply pipe SP3 is mechanically connected to supply pipe SP4 via one automatic switching valve V1, and further mechanically connected to additive injection section 7a, and is also mechanically connected to supply pipe SP5 via the other automatic switching valve V2, and is mechanically connected to ground holding material supply section RS. A supply pump PP2 is also mechanically interposed at the starting end of this supply pipe SP3, so as to pump the additive to additive injection section 7a or ground holding material supply section RS.

[0098] In this embodiment, the flow paths of the supply pipe SP3, supply pump PP2, automatic switching valve V1, supply pipe SP4 and additive injection section 7a are part of the additive supply system, while the flow paths of the supply pipe SP3, supply pump PP2, automatic switching valve V2, supply pipe SP5 and ground retention material supply section RS are part of the ground retention material supply system.

[0099] The additive supply system is equipped with a polymer-added mud injection section PAS. This polymer-added mud injection section PAS is mechanically connected to the additive injection section 7a via supply piping SP6, making it possible to add polymer-added mud to the additive. This polymer-added mud injection section PAS is installed on a trailing bogie (not shown) for installing the polymer-added mud injection section behind the mud pressure shield machine 1.

[0100] The supply pipe SP5 branched off at the flow path switching section LC is mechanically connected to the mud adjustment tank RSc of the ground holding material supply section RS. Note that an electromagnetic flow meter (not shown) is interposed in the supply pipe SP5 to measure the flow rate of the additive supplied to the mud adjustment tank RSc.

[0101] In the mud-adding material adjustment tank RSc, the additives are supplied into the tank through the supply pipe SP5, and water supplied into the tank from the water supply unit RSw is added to dilute the additives. Note that an electromagnetic flow meter (not shown) is installed in the pipe connecting the water supply unit RSw and the mud-adding material adjustment tank RSc to measure the flow rate of the water supplied to the mud-adding material adjustment tank RSc.

[0102] The mud adjustment tank RSc is mechanically connected to the batch mixer RSm via a supply pipe SP7. A supply pump PP3 is mechanically interposed in the middle of this supply pipe SP7, making it possible to pressure-feed the additives adjusted in the mud adjustment tank RSc to the batch mixer RSm. The mud adjustment tank RSc and supply pump PP3 are installed on a trailing carriage (not shown) for installing the adjustment tank behind the mud pressure shield machine 1.

[0103] In the batch mixer RSm, a polymer agent (liquid) sent from the polymer agent supply unit RSp is added to an additive (fluid) supplied from the mud-adding material adjustment tank RSc through supply piping SP7, and the mixture is stirred to produce a ground-retaining material. The batch mixer RSm and polymer agent supply unit RSp are installed on a follow-up truck (not shown) for mixer installation behind the mud pressure shield machine 1.

[0104] The batch mixer RSm is mechanically connected to the inlet of the injection pump 15pp through a supply pipe SP1. An electromagnetic flow meter (not shown), for example, is provided in the middle of the supply pipe SP1 connected to the outlet of the injection pump 15pp to measure the flow rate of the ground retention material discharged from the injection pump 15pp.

[0105] Next, an example of a method for supplying the ground holding material according to this embodiment will be described with reference to FIG.

[0106] First, an additive (fluid) made up of a mixture of bentonite and water or the like supplied from the additive supply unit AS is pumped by the supply pump PP1 to the flow path switching unit LC.

[0107] Next, the additive material is supplied to the mud adjustment tank RSc of the ground retention material supply unit RS via the flow path switching unit LC, and water is added from the water supply unit RSw to dilute the additive material, and then the additive material is pumped to the batch mixer RSm by the supply pump PP3.

[0108] In the batch mixer RSm, the additive (fluid) supplied from the mud-adding material adjustment tank RSc through the supply pipe SP7 is mixed with the polymer agent (liquid) sent from the polymer agent supply section RSp to produce a ground-holding material, which is then sent to the injection pump 15pp through the supply pipe SP1 and pressure-fed into the interior of the cylindrical body 15c of the ground exploration device 15 by the injection pump 15pp.

[0109] In this embodiment, the additives already provided in the earth pressure shield machine 1 are By branching off the material supply unit AS by the supply pipe SP3 and using it as part of the supply system for ground holding material, it is possible to supply ground holding material into the cylindrical body 15c of the ground exploration unit 15 without providing a new additive supply unit AS for ground supply. This makes it possible to make the supply system that supplies ground holding material to the ground exploration device 15 small-scale. As a result, the overall system of the mud pressure shield machine 1 can also be made small-scale.

[0110] (Second embodiment)

[0111] Figure 18(a) is a plan view of the top surface of the cylindrical body that constitutes the natural ground exploration device of Figure 7, and Figure 18(b) is an enlarged cross-sectional view of the main part taken along line II-II in Figure 18(a). Note that arrow A in the figure indicates the excavation direction of the mud shield machine 1 (the axial direction of the mud shield machine 1 or the extension direction of the excavation hole).

[0112] In the first embodiment described above, since the upper surface of the cylindrical body 15c constituting the ground exploration device 15 is open, when the mud shield tunneling machine 1 excavates the ground, gravel or the like may enter the inside of the cylindrical body 15c through the opening, or the opening may be blocked by gravel or the like, which may result in the propagation of ultrasonic waves being hindered, resulting in the problem that it may not be possible to explore the condition of the ground directly above the mud shield tunneling machine 1.

[0113] Therefore, in this embodiment, a lattice member 15g is provided at the opening on the top surface of the cylindrical body 15c as shown in Fig. 18. This makes it possible to prevent gravel and the like from entering the inside of the cylindrical body 15c and from blocking the opening of the cylindrical body 15c.

[0114] 18(a), the grid member 15g is configured by, for example, a pair of first members 15g1 and a pair of second members 15g2 arranged in a grid shape in a plan view. That is, the grid member 15g is configured by installing a pair of first members 15g1 arranged parallel to each other and spaced apart, and a pair of second members 15g2 arranged parallel to each other and spaced apart, so that the first members 15g1 and the second members 15g2 are arranged perpendicular to each other.

[0115] As shown in Figures 18(a) and (b), the first member 15g1 and the second member 15g2 are made of, for example, a thin, rod-shaped steel material having a circular cross section, and are installed so as not to protrude from the upper surface of the cylindrical body 15c, as shown in Figure 18(b).

[0116] 18(a), the pair of first members 15g1 are arranged perpendicular to the excavation direction A of the earth pressure shield machine 1. Meanwhile, the pair of second members 15g2 are arranged perpendicular to the pair of first members 15g1. In other words, the pair of second members 15g2 are arranged extending along the excavation direction A of the earth pressure shield machine 1.

[0117] 18(b), the pair of second members 15g2 are placed on top of the pair of first members 15g1. This allows gravel and the like to flow backward along the second members 15g2 extending in the excavation direction A, preventing them from remaining on the opening AP1 (see FIG. 18(a)) surrounded by the pair of first members 15g1 and the pair of second members 15g2.

[0118] 18(a), the opening AP1 surrounded by the pair of first members 15g1 and the pair of second members 15g2 is formed, for example, in a square shape, and is formed point-symmetrically with respect to the center of the upper surface of the cylindrical body 15c as the center of symmetry, and is also formed symmetrically in the vertical and horizontal directions with respect to the central axis of the upper surface of the cylindrical body 15c as the axis of symmetry. This allows for good propagation of ultrasonic waves. Note that, although not particularly limited, the adjacent distance D1 between the pair of first members 15g1 is, for example, approximately 60 mm, and the adjacent distance D2 between the pair of second members 15g2 is, for example, approximately 60 mm.

[0119] In this embodiment, by providing grid member 15g at the opening on the top surface of cylindrical body 15c, it is possible to prevent gravel and the like from entering the interior of cylindrical body 15c and blocking the opening on the top surface of cylindrical body 15c. In other words, since the propagation of ultrasonic waves is not obstructed by gravel and the like, ultrasonic waves can be propagated smoothly. Therefore, the natural ground exploration device 15 using an ultrasonic sensor can effectively explore the condition of the natural ground directly above the mud pressure shield machine 1.

[0120] Furthermore, the inventors' investigations have revealed that providing grid members 15g at the openings on the top surface of cylindrical body 15c may cause diffuse reflection of ultrasonic waves. Therefore, in this embodiment, the surfaces of grid members 15g (i.e., first member 15g1 and second member 15g2) are coated with, for example, rubber or resin by coating or the like. This makes it possible to suppress or prevent diffuse reflection of ultrasonic waves even when grid members 15g are provided at the openings on the top surface of cylindrical body 15c, so that the natural ground condition directly above mud pressure shield machine 1 can be well explored by natural ground exploration device 15 using an ultrasonic sensor.

[0121] (Modification 1 of grid-like member)

[0122] Figure 19(a) is a plan view of a modified example of a grid member provided on the upper surface of a cylindrical body constituting the natural ground exploration device of Figure 7, and Figure 19(b) is a plan view showing the function of the grid member of Figure 19(a).

[0123] In the present embodiment, the lattice member 15g is configured, for example, by a pair of first members 15g1 and a pair of second members 15g2 arranged in a lattice-like configuration in a plan view. That is, the pair of first members 15g1 are provided near the outside of the pair of first members 15g1, and the pair of second members 15g2 are provided near the outside of the pair of second members 15g2. This increases the number of lattices arranged between the inner periphery of the opening of the cylindrical body 15c and the central opening AP1 of the lattice member 15g compared to the first modification example described above, making it more difficult for gravel and the like to enter the interior of the cylindrical body 15c.

[0124] Although not particularly limited, the adjacent distance D1 between the pair of first members 15g1 and the adjacent distance D2 between the pair of second members 15g2 are the same as those described above, e.g., about 60 mm. The narrower adjacent distance D3 between the pair of first members 15g1 and the narrower adjacent distance D4 between the pair of second members 15g2 are, e.g., about 20 mm.

[0125] Furthermore, the first member 15g1 and the second member 15g2 are arranged so as to be perpendicular to each other, as in the above-mentioned variant example 1, and the central opening AP1 surrounded by a pair of first members 15g1 and a pair of second members 15g2 is formed in a square shape, but the first member 15g1 and the second member 15g2 are arranged so as to be diagonal to the excavation direction A, and the diagonal line DL (see Figure 19(a)) connecting one diagonal corner of the central opening AP1 is arranged so as to be perpendicular to the excavation direction A.

[0126] That is, the grid member 15g is arranged so that the other diagonal corner of the opening AP1 faces forward and backward of the earth pressure shield machine 1. This allows gravel GR and the like to flow backward along the first member 15g1 and the second member 15g2 that extend obliquely to the excavation direction A, as shown in Figure 19(b), and prevents the gravel GR and the like from flowing onto the opening AP1.

[0127] Therefore, in this embodiment as well, gravel GR and the like can be prevented from entering the interior of the cylindrical body 15c or blocking the opening on the top surface of the cylindrical body 15c, so that the condition of the ground directly above the mud pressure shield tunneling machine 1 can be effectively explored using the ground exploration device 15 using an ultrasonic sensor.

[0128] Also in this embodiment, as in the second embodiment, the surface of the lattice member 15g (i.e., the first member 15g1 and the second member 15g2) can be coated with, for example, rubber or resin by a coating method or the like to suppress or prevent diffuse reflection of ultrasonic waves, so that the condition of the ground directly above the mud pressure shield machine 1 can be well explored by the ground exploration device 15 using an ultrasonic sensor.

[0129] (Modification 2 of grid-like member)

[0130] FIG. 20 is a plan view of a modified example of the grid member provided on the upper surface of the cylindrical body that constitutes the natural ground exploration device of FIG.

[0131] In this embodiment, the lattice-like member 15g is also composed of, for example, a pair of first members 15g1 and a pair of second members 15g2 arranged in a lattice-like pattern when viewed in a plane, and the first members 15g1 and the second members 15g2 are arranged so as to be oblique to the excavation direction A.

[0132] However, in this embodiment, the opening AP2 surrounded by a pair of first members 15g1 and a pair of second members 15g2 is formed in a diamond shape in a plan view, with one diagonal angle formed at an acute angle and the other diagonal angle formed at an obtuse angle.

[0133] The grid member 15g is arranged so that the diagonal line DL connecting the pair of obtuse angles of the openings AP2 is perpendicular to the excavation direction A. In other words, the grid member 15g is arranged so that the pair of acute angles of the openings AP2 face forward and backward of the earth pressure shield machine 1.

[0134] As a result, in this embodiment, the inclination angle of the first member 15g1 and the second member 15g2 relative to the excavation direction A is smaller than in variant example 1 (Figure 19(a)), so gravel and the like can flow backward along the first member 15g1 and the second member 15g2 more easily than in variant example 1, and can be prevented from flowing over the opening AP2.

[0135] Therefore, in this embodiment as well, gravel and the like can be prevented from entering the interior of the cylindrical body 15c or blocking the opening on the top surface of the cylindrical body 15c, so that the condition of the ground directly above the mud pressure shield machine 1 can be effectively explored using the ground exploration device 15 using an ultrasonic sensor.

[0136] Also in this embodiment, as in the second embodiment, the surface of the lattice member 15g (i.e., the first member 15g1 and the second member 15g2) can be coated with, for example, rubber or resin by a coating method or the like to suppress or prevent diffuse reflection of ultrasonic waves, so that the condition of the ground directly above the mud pressure shield machine 1 can be well explored by the ground exploration device 15 using an ultrasonic sensor.

[0137] (Modification 3 of the grid-like member)

[0138] 21(a) is a plan view of a modified example of a grid member provided on the upper surface of a cylindrical body constituting the natural ground exploration device of FIG. 7, and FIG. 21(b) is an enlarged cross-sectional view of a main part taken along line III-III of FIG. 21(a).

[0139] As shown in Figures 21(a) and (b), in this embodiment, the lattice member 15g is composed of a third member 15g3 which has a circular frame shape in a plan view and is positioned at the center of the opening on the top surface of the cylindrical body 15c, and curved fourth members 15g4 which are positioned on top of the third member 15g3, two on each side of the third member 15g3.

[0140] In this embodiment, the opening AP3 is formed in a circular shape. The circular frame-shaped third member 15g3 that forms the opening AP3 is joined to the fourth member 15g4 on the third member 15g3, and is therefore located at the center of the opening on the upper surface of the cylindrical body 15c. Note that, although not particularly limited, the diameter of the opening AP3 is greater than the adjacent interval D1 described above.

[0141] Also, as shown in Figure 21(a), the two fourth members 15g4 arranged on each side of the central third member 15g3 start from the upper side of Figure 21 at the opening on the top surface of the cylindrical body 15c, extend out to the left and right to avoid the opening AP3, and extend from the left and right sides of the outer periphery of the opening AP3 toward the lower side of Figure 21 at the opening on the top surface of the cylindrical body 15c so as to approach each other.

[0142] In this embodiment, the fourth member 15g4 is arranged on the outer periphery of the circular frame-shaped third member 15g3, and therefore the number of lattices between the inner periphery of the opening of the cylindrical body 15c and the central opening AP3 is increased compared to the second embodiment, making it difficult for gravel and the like to enter the inside of the cylindrical body 15c.

[0143] Furthermore, in this embodiment, as in the above-mentioned variant example 2, the inclination angle of the fourth member 15g4 with respect to the excavation direction A is smaller than in the case of variant example 1, so gravel and the like can flow more easily backward along the fourth member 15g4 than in the case of variant example 1 above, and can be prevented from flowing over the opening AP3 within the frame of the third member 15g3.

[0144] Therefore, in this embodiment as well, gravel and the like can be prevented from entering the interior of the cylindrical body 15c or blocking the opening on the top surface of the cylindrical body 15c, so that the condition of the ground directly above the mud pressure shield machine 1 can be effectively explored using the ground exploration device 15 using an ultrasonic sensor.

[0145] Also in this embodiment, as in the second embodiment, the surface of the lattice member 15g (i.e., the third member 15g3 and the fourth member 15g4) can be coated with, for example, rubber or resin by a coating method or the like to suppress or prevent diffuse reflection of ultrasonic waves, so that the condition of the ground directly above the mud pressure shield machine 1 can be well explored by the ground exploration device 15 using an ultrasonic sensor.

[0146] (Third embodiment)

[0147] 22 is a plan view of the mud pressure shield machine of FIG. 1 seen from above, FIG. 23 is a cross-sectional view taken along line IV-IV of FIG. 22, and FIG. 24 is an enlarged cross-sectional view of the main parts of the mud pressure shield machine of FIG.

[0148] As described above, when forming an excavation tunnel in the ground using a shield tunneling machine, if, for example, there is a sudden intake of excavated soil, the ground is soft, or a sharp curve is being constructed, excessive over-excavation may occur in the over-excavation section between the outer surface of the shield tunneling machine's skin plate and the inner surface of the excavation tunnel, or the ground may become loose and unstable.

[0149] Therefore, in this embodiment, as shown in Figures 22, 23 and 24, when an excavation hole DP is formed in the ground G by the mud pressure shield machine 1, the condition of the ground G is explored by the ground exploration device 15 as described above, and while continuing excavation without stopping, the over-excavation section ES between the outer surface of the skin plates M1, M2 of the mud pressure shield machine 1 and the inner surface of the excavation hole DP is filled with ground retention material R pressurized into the inside of the cylindrical body 15c.

[0150] As a result, according to this embodiment, when the excavation hole DP is formed in the ground G by the mud pressure shield machine 1, the condition of the ground G can be confirmed by the ground exploration device 15, and even if excessive overexcavation occurs, the overexcavation part ES can be filled with ground retention material R. This makes it possible to improve the stability of the ground G.

[0151] Furthermore, the position of the earth pressure shield machine 1 in the excavation hole DP can be stabilized, allowing for highly accurate linear control.

[0152] Furthermore, by filling the overexcavation section ES with ground retention material R while continuing excavation without stopping the excavation of the mud pressure shield machine 1, construction efficiency can be improved compared to when excavation is stopped and filling material is filled into the overexcavation section ES, thereby shortening the construction period and reducing construction costs.

[0153] (Variations of the over-digging and filling method)

[0154] FIG. 25 is a cross-sectional view taken along line IV-IV in FIG. 22, which explains a modified example of the method for filling the extra trench.

[0155] As shown in Figure 25, in this modified example, a ground retention material injection section 17 for injecting ground retention material R into the overexcavation section ES is installed symmetrically on the side of the skin plate M1 of the mud pressure shield machine 1 at the midpoint in the height direction of the mud pressure shield machine 1.

[0156] The ground retention material R released from this ground retention material injection section 17 is filled into the overexcavation section ES below the middle in the height direction of the earth pressure shield machine 1. This makes it possible to shorten the filling time of the overexcavation section ES.

[0157] In particular, when the diameter of the earth pressure shield machine 1 is large, it takes time to fill the overexcavation section ES with only the ground retention material R discharged from the cylindrical body 15c, and this may not be sufficient. In contrast, in this embodiment, the overexcavation section ES is filled with the ground retention material R discharged from the ground retention material injector 17 in addition to the cylindrical body 15c, so that even in the case of a large diameter shield machine, such as one with a diameter of 5000 mm or more, it is possible to adequately fill the overexcavation section ES.

[0158] The installation positions of the ground retention material injection units 17 are not limited to the positions shown in Figure 25 and can be changed in various ways, for example, the ground retention material injection units 17 may be installed symmetrically below the midpoint in the height direction of the earth pressure shield machine 1, or ground retention material injection units 17 may be installed symmetrically below the midpoint in the height direction of the earth pressure shield machine 1 in addition to Figure 25. Furthermore, for example, ground retention material injection units 17 may be installed at multiple locations along the excavation direction of the earth pressure shield machine 1.

[0159] The invention made by the inventor has been specifically described above based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects and are not limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the description of the above embodiments, but should be interpreted solely in accordance with the claims, and includes technologies equivalent to the technologies described in the claims and all modifications that do not deviate from the gist of the claims.

[0160] In the above embodiment, an example is given of the use of an earth pressure shield machine with a ribbon-type screw conveyor, but this is not limited to this, and for example, an earth pressure shield machine with an axle-type screw conveyor in which the shaft is at the center of the conveyor and blades are provided around the shaft may also be used.

[0161] Furthermore, in the second embodiment, a lattice-like member is provided at the opening on the top surface of the cylindrical body, but this is not limited to this, and for example, a mesh-like member may be provided.

[0162] In addition, Figures 18 to 21 show an example in which the lattice member 15g is formed by providing multiple first members 15g1 and multiple second members 15g2, but the lattice member 15g can also be formed by providing one first member 15g1 and one second member 15g2. [Industrial Applicability]

[0163] In the above explanation, the present invention is applied to an earth pressure shield machine, but the present invention can also be applied to a mud water pressure shield machine. [Explanation of symbols]

[0164] 1 Mud pressure shield tunneling machine 2 cutter heads 2H hub section 2R outer ring 2S spoke part 2F face plate section 2FR connecting rod section 2A opening 3. Device body 3a Front trunk 3b Back torso 3c Tail seal part 4 chambers Bits 5a to 5d 6. Scraper Touse 7a~7c Additive injection part 8 Bulkhead plate 9a fixed wing 9b Stirring blade 10 Earth pressure gauge 11 Cutter driver 12a folding jack 12b Shield Jack 13 Screw conveyor 13B Blade 14 Erector 15. Ground exploration equipment 15h through hole 15c Cylindrical body 15p plate 15f frame 15b bolt 15n nut 15ih injection hole 15ip injection piping 15pp infusion pump 15ppm drive motor 15v1 Opening and Closing Valve 15v2 Pressure Relief Valve 15v3 swing valve 15v4 ball valve 15ps pressure sensor (pressure detection means) 15ss ultrasonic sensor 15g lattice material 15g1 First component 15g2 Second component 15g3 Third component 15g4 4th member 16. Ground collapse detection device 17 Ground retention material injection section M1, M2 skin plate SG Segment G. Ground C1~C6 cables PM pressure measuring instrument LM distance measuring device MC control section MD monitor US,USs,USr Ultrasound CA cavity R Ground retention material RS Ground Retention Material Supply Department RSc muddy material adjustment tank RSw Water Supply Department RSm Batch Mixer RSp Polymer Supply Department SP1~SP7 supply piping AS additive supply section PP1~PP3 supply pump LC flow path switching unit V1, V2 automatic switching valve PAS polymer muddying material injection part AP1,AP2,AP3 opening DL Diagonal DP drilling hole ES Overexcavation

Claims

1. A through hole provided at the top of the skin plate of the shield machine, penetrating the inside and outside of the skin plate; a cylindrical body provided with an outer peripheral surface of an upper end portion connected to an inner peripheral surface of the through hole; an injection hole provided on the outer peripheral surface of the cylindrical body so as to penetrate the cylindrical body from the inside to the outside; an injection pipe connected to the injection hole; an injection pump that pumps the ground holding material into the cylindrical body through the injection piping; a pressure detection means for detecting an injection pressure inside the injection pipe; a plate-like body attached to the lower end surface of the cylindrical body; an ultrasonic sensor attached to the underside of the plate-like body; a shield tunneling machine equipped with a natural ground exploration device, characterized in that, when forming an excavation hole in the ground by the shield tunneling machine equipped with a natural ground exploration device comprising the above-mentioned, the overexcavation section between the outer surface of the skin plate and the inner surface of the excavation hole is filled with the natural ground retention material pressurized into the inside of the cylindrical body.

2. A method for filling an overexcavation section of a shield tunneling machine equipped with a ground exploration device as described in claim 1, characterized in that the ground retention material released from a ground retention material injection section provided on the side of the skin plate of the shield tunneling machine is filled into the overexcavation section.

3. 3. The over-excavation filling method for a shield tunneling machine equipped with a natural ground exploration device according to claim 1, wherein the ground retention material is a mixture of bentonite, a polymeric agent, and water.

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