Sediment removal system and sediment removal method

Abstract

To provide a sediment discharge system capable of reducing the amount of mud discharged compared to the conventional system while suppressing pressure resistance.SOLUTION: A sediment removal system 1 uses a pressure pump 20 to transport excavated sediment generated by excavation with a shield tunneling machine and excavation additives that promote plastic fluidization of the excavated sediment via a pressure pipe 21, and comprises a pressure additive injection device 31 that injects pressure additives containing at least water into the pressure pipe 21, pressure detectors 32, 33 that detect the pressure of the pressure pump 20 and the pressure pipe 21, and a control device 35 that controls the pressure additive injection device 31 based on the pressure detected by the pressure detectors 32, 33.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a soil transport system and a soil transport method for transporting soil containing excavated soil generated by excavation using a shield machine and an excavation additive that promotes plastic fluidization of the excavated soil using a pressure pump through a pressure pipe. [Background technology]

[0002] This type of soil transport system is disclosed, for example, in Patent Document 1. In this soil transport system, in order to reduce the frictional resistance (pumping resistance) between the discharged soil flowing through the pressure pipe and the inner surface of the pressure pipe and to perform smooth pumping, a water injection ring is provided in the pressure pipe and water is injected into the pressure pipe through the water injection ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-279587 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional soil removal systems such as that described in Patent Document 1, changes in the properties of the soil being pumped increase the resistance to pumping, and there is a concern that the pumping pipes may become clogged, which often results in excessive water being injected, increasing the amount of muddy soil (mud) being removed and increasing the burden of post-processing the mud.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a soil and sand transportation system and method that can reduce the amount of mud transported while suppressing pressure resistance, more than in the conventional method. [Means for solving the problem]

[0006] The characteristic configuration of the soil removal system according to the present invention for solving the above problems is as follows: A soil discharge system that discharges soil containing excavated soil generated by excavation using a shield machine and an excavation additive that promotes plastic fluidization of the excavated soil using a pressure pump through a pressure pipe, A pressure-feeding additive injection device that injects a pressure-feeding additive into the pressure-feeding pipe to reduce pressure-feeding resistance; a pressure detection means for detecting a pressure of the pressure pump and / or the pressure pipe; A control device that controls the pressure-feed additive injection device based on the pressure detected by the pressure detection means; The purpose of this study is to provide

[0007] In the soil transport system of this configuration, the pressure of the pump and / or pipe, which tends to change depending on the properties of the soil being discharged, is detected by the pressure detection means, and the control device controls the pumping additive injection device based on the detected pressure. This allows the amount of pumping additive injected into the pipe to reduce pumping resistance to be determined according to the properties of the soil being discharged, and the soil is pumped and transported as mud with the optimal amount of pumping additive injected, just enough. Therefore, the amount of mud transported can be reduced compared to conventional methods while suppressing pumping resistance.

[0008] In the soil removal system according to the present invention, It is preferable that the control device controls the pressure-fed additive injection device to maintain the current injection amount of the pressure-fed additive when the pressure detected by the pressure detection means is smaller than an upper pressure limit value and larger than a lower pressure limit value.

[0009] According to the soil removal system of this configuration, when the pressure detected by the pressure detection means is smaller than the upper pressure limit value and larger than the lower pressure limit value, in other words, to the extent that the characteristics of the soil discharged change slightly, the current injection amount is maintained, so that the overall amount of mud removed can be kept low while fluctuations in the amount of mud removed can be suppressed.

[0010] In the soil removal system according to the present invention, The pumping additive contains an improvement agent that improves the soil quality of the discharged soil to a soil quality suitable for pumping, The pressure-fed additive injection device includes a concentration adjustment unit that adjusts the concentration of the improver in the pressure-fed additive, The control device includes: A discrimination unit that discriminates whether the excavated soil is mainly clayey soil or mainly sandy soil, When it is determined that the excavated soil is mainly clayey soil, the concentration adjusting unit is controlled to reduce the concentration of the improver; When it is determined that the excavated soil is mainly sandy soil, it is preferable to control the concentration adjusting unit so as to increase the concentration of the improver.

[0011] According to the soil transport system of this configuration, if the judgment by the judgment unit determines that the excavated soil is mainly clayey soil, the concentration of the improvement agent is decreased, whereas if the excavated soil is mainly sandy soil, the concentration of the improvement agent is increased. This makes it possible to unify the discharged soil with the optimum improvement agent concentration, neither too much nor too little, and improve the soil quality to be suitable for pumping.

[0012] In the soil removal system according to the present invention, Further, a discharged soil amount measuring means for measuring the discharged soil amount is provided, The excavation cross-sectional area of ​​the shield tunneling machine is S, The tunneling stroke length of the shield tunneling machine is Ls, The amount of the excavation additive added when the shield machine excavates by the excavation stroke length (Ls) is Q, The theoretical soil discharge volume is V1, When the shield machine excavates by the excavation stroke length (Ls), the measured amount of discharged soil measured by the discharged soil amount measuring means is V2 (V1 ≧ V2), The discrimination unit is When the difference (V1-V2) between the theoretical discharge amount V1 (=S×Ls+Q) and the measured discharge amount V2 is equal to or less than a first predetermined value α (V1-V2≦α), it is determined that the excavated soil is mainly clayey soil, When the difference (V1-V2) is equal to or greater than a second predetermined value β (>α) that is greater than the first predetermined value α (V1-V2≧β), it is preferable to determine that the excavated soil is mainly sandy soil.

[0013] The higher the composition ratio of clayey soil in the ground excavated by the shield machine, the less the amount of free water (groundwater) in the pores pushed out into the ground. As a result, the amount of soil discharged measured by the soil discharge volume measuring means approaches the theoretical soil discharge volume, and the difference between the theoretical soil discharge volume and the measured soil discharge volume becomes smaller. On the other hand, the higher the composition ratio of sandy soil in the ground, the more the amount of free water (groundwater) in the pores pushed out into the ground. As a result, the amount of soil discharged measured by the soil discharge volume measuring means deviates from the theoretical soil discharge volume, and the difference between the theoretical soil discharge volume and the measured soil discharge volume becomes larger. According to this configuration of soil removal system, when the difference (V1-V2) between the theoretical soil discharge volume V1 (=S×Ls+Q) and the measured soil discharge volume V2 is less than or equal to a first predetermined value (V1-V2≦α), the excavated soil is determined to be mainly clayey soil, and when the difference (V1-V2) is greater than or equal to a second predetermined value β (>α) that is greater than the first predetermined value α (V1-V2≧β), the excavated soil is determined to be mainly sandy soil, making it possible to accurately determine whether the excavated soil is mainly clayey soil or mainly sandy soil.

[0014] Next, the characteristic configuration of the soil removal method according to the present invention for solving the above problems is as follows: A method for transporting soil and sand generated by excavation using a shield machine and an additive for excavation that promotes plastic fluidization of the excavated soil and sand by a pressure pump through a pressure pipe, a pressure detection step of detecting a pressure of the pressure pump and / or the pressure pipe; A control step of controlling an injection amount of a pressure-feeding additive to the pressure-feeding pipe to reduce a pressure-feeding resistance based on the pressure detected in the pressure detection step; The purpose of this study is to encompass the above.

[0015] According to the soil removal method of this configuration, the pressure of the pump and / or the pumping piping, which tends to change in response to the properties of the discharged soil, is detected in a pressure detection step, and the amount of pumping additive injected into the pumping piping to reduce pumping resistance is controlled in a control step based on the detected pressure. This allows the amount of pumping additive injected into the pumping piping to correspond to the properties of the discharged soil, and the discharged soil is pumped with an optimal amount of pumping additive, neither too much nor too little, and is transported as mud. Therefore, the amount of mud transported can be reduced more than before while suppressing pumping resistance. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an explanatory diagram of a shield construction method to which a soil removal system according to one embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a schematic diagram showing a schematic configuration of the soil removal system of this embodiment. [Diagram 3] FIG. 3 is a flow chart showing the procedure for processing excavated soil (soil removal method) in the soil removal system of this embodiment. [Figure 4] FIG. 4 is a graph illustrating the measured amount of discharged soil relative to the theoretical amount of discharged soil. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the present invention will be described with reference to the drawings. However, the present invention is not intended to be limited to the embodiments described below or the configurations shown in the drawings.

[0018] <Outline of the shield method> Fig. 1 is an explanatory diagram of a shield tunneling method to which an earth and sand removal system 1 according to an embodiment of the present invention is applied. In the shield tunneling method shown in Fig. 1, a mud pressure type shield tunneling machine 10 is used, which is provided with a chamber 13 formed between a cutter head 11 facing the tunnel face and a partition wall 12 arranged at a predetermined distance from the cutter head 11. In the shield tunneling method shown in Fig. 1, the shield tunneling machine 10 is started from the starting shaft 5 while rotating the cutter head 11, and assembling segments into an annular shape at the rear of the shield tunneling machine 10 while excavating toward the left side in the figure, thereby laying a plurality of ring bodies 15a in the tunnel axial direction behind the shield tunneling machine 10 to construct a tunnel lining 15.

[0019] An excavation additive is injected into the chamber 13 by an excavation additive injection device 17 having an excavation additive injection pipe 16 connected in communication with the chamber 13, and excavated soil produced by excavation caused by the rotation of the cutter head 11 is taken into the chamber 13. The excavation additive is added to the excavated soil taken into the chamber 13 to impart plastic fluidity and water-stopping properties, and known additives such as mineral-based, surfactant-based, highly water-absorbent resin-based, and water-soluble polymer-based additives can be used. In this way, the excavated soil is filled into the chamber 13 in a plastically fluidized state.

[0020] In the shield machine 10, the reaction force required for tunneling is taken by a propulsion jack (not shown), which is pushed against the tip of the tunnel lining 15 and extended to propel the shield machine 10. The propulsion force at this time pressurizes the excavated soil, which has become plastically fluidized in the chamber 13, and this earth pressure acts on the tunnel face, thereby holding the face in place.

[0021] As new excavated soil is successively taken into the chamber 13, the screw conveyor 18 disposed inside the machine in communication with the chamber 13 is rotated to discharge the excavated soil in a plastically fluidized state from the chamber 13 as discharged soil so as to balance with the new excavated soil taken into the chamber 13. The discharged soil from the screw conveyor 18 is then transported by pressure pumps 20a to 20e, which will be described later, through pressure pipes 21a to 21e, which will be described later and into which a pressure additive is injected to reduce pressure resistance, and is stored as muddy discharged soil (mud) in a mud pit (not shown) installed above the starting base.

[0022] <Pressure pump, pressure pipe> A primary pressure pump 20a is disposed at the rear end of the screw conveyor 18 via a discharge duct 19. A first relay pressure pump 20b, a second relay pressure pump 20c, a third relay pressure pump 20d, and a fourth relay pressure pump 20e are disposed at predetermined intervals in the tunnel axial direction from the primary pressure pump 20a toward the tunnel mouth. The pressure pumps 20a to 20e include rotary and double-barrel piston pumps, but in this example, a double-barrel piston pump with high pressure capacity is used.

[0023] <Pressure pipe> A primary pressure-feeding pipe 21a is provided between the primary pressure-feeding pump 20a and the first relay pressure-feeding pump 20b. A secondary pressure-feeding pipe 21b is provided between the first relay pressure-feeding pump 20b and the second relay pressure-feeding pump 20c. A tertiary pressure-feeding pipe 21c is provided between the second relay pressure-feeding pump 20c and the third relay pressure-feeding pump 20d. A quaternary pressure-feeding pipe 21d is provided between the third relay pressure-feeding pump 20d and the fourth relay pressure-feeding pump 20e. A quinary pressure-feeding pipe 21e is provided between the fourth relay pressure-feeding pump 20e and a mud pit (not shown) in the ground facility. An injection ring 23 having a plurality of ejection ports (not shown) opening into the pipe toward the pressure-feeding direction is provided in the vicinity of the discharge port of the pressure-feeding pumps 20a to 20e to which the pressure-feeding pipes 21a to 21e are connected. In the following description, the "pressure pumps 20a to 20e" are collectively referred to as the "pressure pump 20," and the "pressure pipes 21a to 21e" are collectively referred to as the "pressure pipes 21." Note that, in this embodiment, an example in which five pressure pumps 20 are installed is shown, but the present invention is not limited to this, and the number of installed pumps can be appropriately adjusted depending on the pump capacity, pumping flow rate, shield excavation length, etc., and the number of installed pumps may be four or less or six or more.

[0024] Fig. 2 is a schematic diagram showing the outline of the soil transport system 1 of this embodiment. The soil transport system 1 shown in Fig. 2 includes an additive injection device 31 for injecting additive into the pressure transport pipe 21 through the nozzle of the injection ring 23, a pump pressure detector 32 as a pressure detection means for detecting the pressure of the pressure transport pump 20, a pipe pressure detector 33 as a pressure detection means for detecting the pressure of the pressure transport pipe 21, a discharged soil amount measuring device 34 as a discharged soil amount measuring means for measuring the discharge amount of discharged soil, and a control device 35 for controlling the additive injection device 31.

[0025] <Additive for pumping> Here, the pumping additive is a mixture of a first liquid and a second liquid, and reduces the frictional resistance (pumping resistance) between the discharged soil flowing through the pumping pipe 21 and the inner surface of the pumping pipe 21.

[0026] The first liquid contains at least water (or water alone), and, if necessary, surfactants, etc., can be added appropriately. The second liquid contains an improvement agent that improves the soil quality of the discharged soil to be suitable for pumping. The improvement agent is not particularly limited as long as it can improve the soil quality of the discharged soil to be suitable for pumping, and for example, polymer-based, surfactant-based, polymer / friction oil-based, and silicone-based ones can be used appropriately. For example, polymer-based improvement agents include those mainly composed of acrylic resin-based polymers, which adsorb to the clay silt in the soil and sand to form a protective film, thereby reducing pumping resistance and providing separation resistance to sandy soil. For example, surfactant-based improvement agents include those mainly composed of anionic synthetic surfactants, which are effective in preventing adhesion of clay soil due to the effect of the surfactant. For example, polymer / friction oil-based improvement agents include those blended with acrylic resin and antifriction oil, which exhibits an adhesion prevention effect without consolidation dehydration even under high pressure. Examples of silicone-based improvers include those containing a silicone-based defoaming agent as the main component. By lowering the surface tension of water, they improve wettability (the ability of a liquid to adhere to a solid surface) and are effective in reducing pumping resistance with a small amount.

[0027] <Additive injection device for pressure feeding> The pumping additive injection device 31 includes a concentration adjustment section 31a that adjusts the concentration of the improver in the pumping additive, a main supply section 31b that supplies the pumping additive, and an injection section 31c that injects the pumping additive. Here, the concentration adjustment section 31a and the main supply section 31b are installed above ground at the departure base (they can also be installed in the departure shaft 5 or the tunnel lining 15). Meanwhile, a plurality of injection sections 31c are provided in the tunnel lining 15 so as to correspond to each of the plurality of injection rings 23 (five in this example).

[0028] <Density adjustment section> The concentration adjusting section 31a includes a first liquid supplying section 41 and a second liquid supplying section .

[0029] [First liquid supply section] The first liquid supply unit 41 includes a first liquid pump 51, a first liquid tank 52, a first liquid suction pipe 53, a first liquid supply pipe 54, and a first liquid pump drive motor 55. In the first liquid supply unit 41, the suction port of the first liquid pump 51 and the first liquid tank 52 are connected by the first liquid suction pipe 53, the base end side of the first liquid supply pipe 54 is connected to the discharge port of the first liquid pump 51, and the first liquid pump 51 and the first liquid pump drive motor 55 are connected so as to be capable of transmitting rotational power.

[0030] [Second liquid supply section] The second liquid supply unit 42 includes a second liquid pump 61, a second liquid tank 62, a second liquid suction pipe 63, a second liquid supply pipe 64, and a second liquid pump drive motor 65. In the second liquid supply unit 42, the suction port of the second liquid pump 61 and the second liquid tank 62 are connected by the second liquid suction pipe 63, the base end side of the second liquid supply pipe 64 is connected to the discharge port of the second liquid pump 61, and the second liquid pump 61 and the second liquid pump drive motor 65 are connected so as to be capable of transmitting rotational power.

[0031] <Main supply section> The main supply unit 31b includes a main supply pump 71, a main tank 72, a main suction pipe 73, a main supply pipe 74, and a main supply pump drive motor 75. In the main supply unit 31b, the suction port of the main supply pump 71 and the main tank 72 are connected by the main suction pipe 73, the base end side of the main supply pipe 74 is connected to the discharge port of the main supply pump 71, and the main supply pump 71 and the main supply pump drive motor 75 are connected so as to be capable of transmitting rotational power.

[0032] <Injection part> The injection section 31c includes an injection pump 81, a sub-tank 82, a sub-suction pipe 83, an injection pipe 84, and an injection pump drive motor 85. In the injection section 31c, the suction port of the injection pump 81 and the sub-tank 82 are connected by the sub-suction pipe 83, the base end side of the injection pipe 84 is connected to the discharge port of the injection pump 81, and the injection pump 81 and the injection pump drive motor 85 are connected so as to be capable of transmitting rotational power.

[0033] In the pressure-fed additive injection device 31, the tip side of the first liquid supply pipe 54 is connected to the main tank 72. The tip side of the second liquid supply pipe 64 is connected to the junction 54a in the middle of the first liquid supply pipe 54. The main supply pipe 74, the base end of which is connected to the discharge port of the main supply pump 71, extends from the ground level of the starting base through the starting shaft 5 into the tunnel lining 15, and is connected to the sub-tanks 82 so that the pressure-fed additive discharged from the main supply pump 71 can be distributed and supplied to each of the multiple sub-tanks 82. The tip side of the injection pipe 84 is connected to the injection ring 23. Each of the pumps 51, 61, 71, 81 is one whose discharge amount changes in proportion to its rotation speed. In this embodiment, an example has been shown in which the concentration adjustment unit 31a and the main supply unit 31b are installed above ground at the starting base, but the present invention is not limited to this. There is also an embodiment in which the concentration adjustment unit 31a and the main supply unit 31b are installed inside the starting shaft 5 or the tunnel lining 15, and the main supply pipe 74 is connected to the sub-tanks 82 so that the pressure-fed additive discharged from the main supply pump 71 can be distributed and supplied to each of the multiple sub-tanks 82.

[0034] In the concentration adjusting section 31a, when the first liquid pump 51 is rotated, the first liquid stored in the first liquid tank 52 is supplied to the junction 54a in the middle of the first liquid supply pipe 54. When the second liquid pump 61 is rotated, the second liquid stored in the second liquid tank 62 is supplied to the junction 54a via the second liquid supply pipe 64. In the junction 54a, the first liquid and the second liquid are merged, and the first liquid and the second liquid mixed by the junction are supplied to the main tank 72 as a pressure-fed additive, and the pressure-fed additive is temporarily stored in the main tank 72. Here, in the concentration adjusting section 31a, the supply amount of the first liquid and the second liquid supplied to the junction 54a can be controlled by controlling the rotation speed of the first liquid pump drive motor 55 and the second liquid pump drive motor 65. Therefore, in the concentration adjustment section 31a, the concentration of the improver in the pumping additive can be adjusted by increasing or decreasing the amount of the second liquid supplied to the confluence section 54a relatively to the amount of the first liquid supplied to the confluence section 54a.

[0035] In the main supply section 31b, when the main supply pump 71 is driven to rotate, the pressure-fed additive stored in the main tank 72 is distributed and supplied to each of the multiple sub-tanks 82 via the main supply pipe 74, and the pressure-fed additive is stored in each sub-tank 82. Here, in the main supply section 31b, by controlling the rotation speed of the main supply pump drive motor 75, the supply amount of the pressure-fed additive distributed and supplied to each of the multiple sub-tanks 82 can be controlled.

[0036] In the injection section 31c, when the injection pump 81 is driven to rotate, the pressure-fed additive stored in the sub-tank 82 is injected into the pressure-fed pipe 21 via the injection tube 84 and the injection ring 23. Here, in the injection section 31c, by controlling the rotation speed of the injection pump drive motor 85, the injection amount of the pressure-fed additive injected into the pressure-fed pipe 21 can be controlled.

[0037] <Pump pressure detector (pressure detection means)> The pump pressure detector 32 is disposed in the discharge pump 20 so as to be able to detect the pressure of the driving hydraulic circuit in the discharge pump 20. A pressure detection signal detected by the pump pressure detector 32 is sent to a control panel 91, which will be described later. The pump pressure detector 32 may be a pressure sensor configured to measure pressure with a pressure-sensitive element, convert it into an electric signal, and output it. Note that the pressure of the driving hydraulic circuit may be calculated based on the current value of an electric motor, which is a power source that generates hydraulic pressure in the discharge pump 20, and such an embodiment is also included in the "pressure detection means" of the present invention.

[0038] <Pipe pressure detector (pressure detection means)> The piping pressure detector 33 is arranged to detect the pressure at a location that is specified in advance based on past cases of blockages in the pumping piping 21. In this example, when the pumping distance between adjacent pumping pumps 20 is Ld, the piping pressure detector 33 is arranged to detect the pressure in the pumping piping 21 at a position that is a distance Ld / 3 downstream in the pumping direction from the pumping pump 20 upstream in the pumping direction. A pressure detection signal detected by the piping pressure detector 33 is sent to a control panel 91, which will be described later. The piping pressure detector 33 may be a pressure sensor similar to the pump pressure detector 32. The piping pressure detector 33 may be arranged to detect the pressure at a location in the pumping piping 21 where the blockage phenomenon of soil discharge is likely to occur, and is not limited to the above-mentioned position Ld / 3 as the pressure detection position.

[0039] <Earth removal measuring device (earth removal measurement means)> The discharged soil amount measuring device 34 is disposed so as to be able to measure the amount of discharged soil discharged through the discharge duct 19 (see FIG. 1). A discharged soil amount measuring signal detected by the discharged soil amount measuring device 34 is sent to a control panel 91, which will be described later. As the discharged soil amount measuring device 34, for example, an electromagnetic flowmeter that measures the flow rate by detecting the magnitude of electromotive force generated according to the flow velocity of the discharged soil flowing through the discharge duct 19 (see FIG. 1) can be used.

[0040] <Control device> The control device 35 is configured to include a control panel 91 mainly composed of a computer, a pressure setting device 92 for setting upper and lower limits of the control pressure in the control panel 91, and an inverter 93 for controlling the rotation speed of the first liquid pump drive motor 55 and the second liquid pump drive motor 65. The control panel 91 includes a calculation unit 91a for performing various calculations and a discrimination unit 91b for discriminating whether the excavated soil is mainly clayey soil or sandy soil, and the functions of the calculation unit 91a and the discrimination unit 91b are exerted by executing a predetermined program created based on the flowchart of Fig. 3 described later. In the control device 35, a control signal is sent from the control panel 91 to the inverter 93, and power of a frequency corresponding to the control signal is sent from the inverter 93 to the first liquid pump drive motor 55 and the second liquid pump drive motor 65, thereby controlling the injection amount of the pumping additive injected into the pumping pipe 21 and the concentration of the improver in the pumping additive.

[0041] FIG. 3 is a flowchart showing the procedure for processing excavated soil (soil transport method) in the soil transport system 1 of this embodiment. The procedure for processing excavated soil by the soil transport system 1 will be described with reference to the flowchart in FIG. 3. In FIG. 3, the symbol "S" indicates a step. The procedure shown in the flowchart in FIG. 3 is performed in a state in which the upper and lower limit values ​​of the control pressure of the pressure pump 20 and the pressure pipe 21 are preset by the pressure setter 92 (see FIG. 2). Here, a pressure upper limit value Hn (e.g., 15 MPa) and a pressure lower limit value Ln (e.g., 10 MPa) are set for the maximum pressure (e.g., 25 MPa) of the pressure pump 20, and a pressure upper limit value Ht (e.g., 3.50 MPa) and a pressure lower limit value Lt (e.g., 2.25 MPa) are set for the maximum pressure (e.g., 6 MPa) in the pressure pipe 21 near the discharge port of the pressure pump 20.

[0042] Fig. 4 is a graph illustrating the measured soil discharge amount V2 against the theoretical soil discharge amount V1. In Fig. 4, the vertical axis indicates the soil discharge amount, and the horizontal axis indicates the number of laid ring bodies 15a. In this example, as shown in Fig. 4, a first threshold value (e.g., 0.95V1) and a second threshold value (e.g., 0.90V1) are set for the theoretical soil discharge amount V1. The difference α (first predetermined value) between the theoretical soil discharge amount V1 and the first threshold value (0.95V1) is set to 0.05V1, and the difference β (second predetermined value) between the theoretical soil discharge amount V1 and the second threshold value (0.90V1) is set to 0.10V1.

[0043] <S1~S2> In the flowchart of Fig. 3, the calculation unit 91a in the control panel 91 shown in Fig. 2 acquires a discharged soil amount measurement signal from the discharged soil amount measuring device 34 (S1). Next, the calculation unit 91a calculates the difference between the theoretical discharged soil amount and the measured discharged soil amount based on the acquired discharged soil amount measurement signal (S2). That is, when the excavation cross-sectional area of ​​the shield tunneling machine 10 is S, the excavation stroke length of the shield tunneling machine 10 (here, the tunnel axial direction length of one ring of the ring body 15a) is Ls, the amount of excavation additive added when the shield tunneling machine 10 excavates the excavation stroke length (Ls) is Q, the theoretical soil discharge volume is V1, and the measured soil discharge volume measured by the soil discharge volume measuring device 34 when the shield tunneling machine 10 excavates the excavation stroke length (Ls) is V2 (V1≧V2), the calculation unit 91a calculates the difference (V1-V2) between the theoretical soil discharge volume V1 (=S×Ls+Q) and the measured soil discharge volume V2.

[0044] <s3> The determination unit 91b determines whether the difference (V1 - V2) calculated by the calculation unit 91a is greater than a first predetermined value α and less than a second predetermined value β (>α) (S3). That is, in FIG. 4, it is determined whether it is greater than the second threshold value (0.90V1) and less than the first threshold value (0.95V1). As shown at point B in FIG. 4, when α < V1 - V2 < β (\"YES\" in step S3), the process proceeds to step S4.

[0045] <S4~S5> [Pressure detection step] In step S4, the control panel 91 acquires the pressure detection signal detected by the pump pressure detector 32. Then, the calculation unit 91a compares the pressure P1 of the pressure feed pump 20 calculated based on the pressure detection signal from the pump pressure detector 32 with the pressure lower limit value Ln and the pressure upper limit value Hn, and determines whether the pressure P1 of the pressure feed pump 20 is greater than the pressure lower limit value Ln and less than the pressure upper limit value Hn (S5). When Ln < P1 < Hn (\"YES\" in step S5), the process proceeds to step S6.

[0046] <S6~S8> [Pressure detection step, control step] In step S6, the control panel 91 acquires the pressure detection signal detected by the pipe pressure detector 33. Then, the calculation unit 91a compares the pressure P2 of the pressure feed pipe 21 calculated based on the pressure detection signal from the pipe pressure detector 33 with the pressure lower limit value Lt and the pressure upper limit value Ht, and determines whether the pressure P2 of the pressure feed pipe 21 is greater than the pressure lower limit value Lt and less than the pressure upper limit value Ht (S7). When Lt < P2 < Ht (\"YES\" in step S7), the control panel 91 controls the injection pump drive motor 85 via the inverter 93 so as to maintain the current injection amount of the pressure feed additive injected into the pressure feed pipe 21 (S8). Thereby, the current injection amount of the pressure feed additive injected into the pressure feed pipe 21 is maintained.

[0047] <s9> In step S3, when the difference (V1-V2) between the theoretical discharge soil amount V1 and the measured discharge soil amount V2 is equal to or less than the first predetermined value α (0≦V1-V2≦α), that is, when the difference is equal to or more than the first threshold value (0.95V1) and equal to or less than the theoretical discharge soil amount V1 as shown by point A in FIG. 4, the determination unit 91b determines that the excavated soil is mainly clayey soil. Then, the control device 35 controls the concentration adjustment unit 31a so as to reduce the concentration of the improvement agent in the pumping additive (S9). That is, the control panel 91 controls the first liquid pump drive motor 55 and the second liquid pump drive motor 65 via the inverter 93 so as to relatively reduce the supply amount of the second liquid to the supply amount of the first liquid supplied to the junction 54a. This reduces the concentration of the improvement agent in the pumping additive.

[0048] <s10> In step S3, the discriminator 91b discriminates that the excavated soil is mainly sandy soil when the difference (V1-V2) between the theoretical soil discharge amount V1 and the measured soil discharge amount V2 is equal to or greater than the second predetermined value β (>α) that is greater than the first predetermined value α (V1-V2≧β), that is, when the difference is in the region of the second threshold value (0.90V2) or less as shown by point C in FIG. 4. Then, the controller 35 controls the concentration adjuster 31a so as to increase the concentration of the improver in the pumping additive (S10). That is, the control panel 91 controls the first liquid pump drive motor 55 and the second liquid pump drive motor 65 via the inverter 93 so as to increase the supply amount of the second liquid relative to the supply amount of the first liquid supplied to the junction 54a. This increases the concentration of the improver in the pumping additive.

[0049] <s11> [Control process] If P1 ≧ Hn in step S5, or if P2 ≧ Ht in step S7, the control panel 91 controls the injection pump drive motor 85 via the inverter 93 so as to increase the amount of pressure-fed additive injected into the pressure-fed pipe 21.

[0050] <s12> [Control process] If P1≦Ln in step S5, or if P2≦Lt in step S7, the control panel 91 controls the injection pump drive motor 85 via the inverter 93 so as to reduce the amount of pressure-fed additive injected into the pressure-fed pipe 21.

[0051] In the shield method shown in Fig. 1, the higher the composition ratio of clay soil in the ground excavated by the shield machine 10, the smaller the amount of free water (groundwater) in the gaps pushed out toward the ground. Therefore, the amount of soil discharged measured by the soil discharge amount measuring device 34 approaches the theoretical soil discharge amount V1, and the difference (V1-V2) between the theoretical soil discharge amount V1 and the measured soil discharge amount V2 becomes smaller. On the other hand, the higher the composition ratio of sandy soil in the ground, the greater the amount of free water (groundwater) in the gaps pushed out toward the ground. Therefore, the amount of soil discharged measured by the soil discharge amount measuring device 34 becomes farther from the theoretical soil discharge amount V1, and the difference (V1-V2) between the theoretical soil discharge amount V1 and the measured soil discharge amount V2 becomes larger.

[0052] In step S3, if the difference (V1-V2) between the theoretical discharged soil amount V1 and the measured discharged soil amount V2 is equal to or less than the first predetermined value α, it is determined that the excavated soil is mainly clayey soil, and if the difference (V1-V2) is equal to or greater than the second predetermined value β (>α), it is determined that the excavated soil is mainly sandy soil, so that it is possible to accurately determine whether the excavated soil is mainly clayey soil or sandy soil. If the excavated soil is determined to be mainly clayey soil as a result of the determination by the determination unit 91b, the concentration of the improvement agent is decreased (S9). On the other hand, if the excavated soil is determined to be mainly sandy soil, the concentration of the improvement agent is increased (S10). In this way, the discharged soil can be integrated by injecting the optimal amount of improvement agent without excess or deficiency, and the soil can be improved to a quality suitable for pumping.

[0053] In step S4, the pressure of the pressure pump 20, which tends to change according to the properties of the discharged soil, is detected by the pump pressure detector 32. In step S7, the pressure of the pressure pipe 21, which tends to change according to the properties of the discharged soil, is detected by the pipe pressure detector 33. Then, the control device 35 controls the pressure additive injection device 31 based on the detected pressure. As a result, the amount of pressure additive injected into the pressure pipe 21 to reduce the pressure resistance corresponds to the properties of the discharged soil, and the discharged soil is pumped with an optimal amount of pressure additive injected, neither too much nor too little, and is transported as mud. Therefore, while suppressing the pressure resistance, the amount of mud transported can be reduced more than in the conventional soil discharge method, which often involves excessive water injection.

[0054] In steps S5 and S7, if the pressure detected by the pressure detectors 33, 34 is less than the preset upper pressure limit (Hn, Ht) and greater than the preset lower pressure limit (Ln, Lt), in other words, the current injection amount is maintained to the extent that the properties of the discharged soil change slightly (S8). This makes it possible to suppress fluctuations in the amount of mud discharged while keeping the overall amount of mud discharged low.

[0055] <Another embodiment> The above describes the soil transportation system and soil transportation method of the present invention based on one embodiment, but the present invention is not limited to the configuration described in the above embodiment, and the configuration can be changed as appropriate within the scope of the spirit of the present invention.

[0056] (1) In the above embodiment, an example was shown in which the pressure-feeding additive injection device 31 is controlled based on the pressure detected by the pressure detectors 33, 34 which detect the pressure of the pressure-feed pump 20 and the pressure-feeding piping 21. However, the pressure-feeding additive injection device 31 may also be controlled based on the pressure detected by the pump pressure detector 32 which detects the pressure of the pressure-feed pump 20, or the piping pressure detector 33 which detects the pressure of the pressure-feeding piping 21.

[0057] (2) In the above embodiment, as shown in FIG. 4, a specific ring body 15a (N 100 , N 200 , N 300 In the above example, the soil type is determined based on the measured soil discharge amount V2 when laying the ring body 15a (N 101-110 , N 201-210 , N 301-310 The soil type may be determined based on the average value of the measured soil discharge volume V2 during laying of the soil.

[0058] (3) In the above embodiment, the pumping additive whose concentration is adjusted by the concentration adjuster 31a is prepared and stored in the main tank 72, the pumping additive stored in the main tank 72 is distributed and supplied by the main supply unit 31b to each of the sub-tanks 82 arranged inside the shield tunneling machine 10 and stored in the sub-tanks 82, and the pumping additive stored in the sub-tanks 82 is injected by the injection unit 31c into the pumping pipe 21 through the injection ring 23, but this is not a limited form of injecting the pumping additive into the pumping pipe 21. For example, in the above embodiment, the tip side of the first liquid supply pipe 54 connected to the main tank 72 may be directly connected to the injection ring 23, and the pumping additive whose concentration is adjusted by the concentration adjuster 31a may be directly injected into the pumping pipe 21 through the injection ring 23. In addition, in the above embodiment, the tip side of the first liquid supply pipe 54 connected to the main tank 72 may be directly connected to the injection ring 23, and the tip side of the second liquid supply pipe 64 connected to the junction 54a in the above embodiment may be directly connected to the injection ring 23, so that the first liquid is directly injected into the pressure delivery pipe 21 via the injection ring 23, and the second liquid is directly injected into the pressure delivery pipe 21 via the injection ring 23. [Industrial Applicability]

[0059] The soil removal system and soil removal method of the present invention can be used in applications in which excavated soil containing excavated soil and excavation additives is removed by a pressure pump through a pressure pipe in a mud pressure shield method. [Explanation of symbols]

[0060] 1. Soil removal system 10 Shield tunneling machine 20 Pressure Pump 21 Pressure pipe 31 Pressure-fed additive injection device 31a Density adjustment section 32 Pump pressure detector (pressure detection means) 33 Pipe pressure detector (pressure detection means) 34 Earth removal amount measuring device (earth removal amount measurement means) 35 Control device 91b Discrimination part

Claims

1. A soil discharge system that discharges soil containing excavated soil generated by excavation using a shield machine and an excavation additive that promotes plastic fluidization of the excavated soil using a pressure pump through a pressure pipe, A pressure-feeding additive injection device that injects a pressure-feeding additive into the pressure-feeding pipe to reduce pressure-feeding resistance; a pressure detection means for detecting a pressure in the pressure pump and / or the pressure pipe; A control device that controls the pressure-feed additive injection device based on the pressure detected by the pressure detection means; A soil removal system equipped with:

2. The soil removal system described in claim 1, wherein the control device controls the pressure-transporting additive injection device to maintain the current injection amount of the pressure-transporting additive when the pressure detected by the pressure detection means is lower than the upper pressure limit value and higher than the lower pressure limit value.

3. The pumping additive contains an improvement agent that improves the soil quality of the discharged soil to a soil quality suitable for pumping, The pressure-fed additive injection device includes a concentration adjusting unit that adjusts the concentration of the improver in the pressure-fed additive, The control device includes: A discrimination unit that discriminates whether the excavated soil is mainly clayey soil or mainly sandy soil, When it is determined that the excavated soil is mainly clayey soil, the concentration adjusting unit is controlled to reduce the concentration of the improver; The soil removal system according to claim 1 or 2, wherein when the excavated soil is determined to be mainly sandy soil, the concentration adjusting unit is controlled so as to increase the concentration of the improvement agent.

4. Further, a discharged soil amount measuring means for measuring the discharged soil amount is provided, The excavation cross-sectional area of ​​the shield tunneling machine is S, The tunneling stroke length of the shield tunneling machine is Ls, The amount of the excavation additive added when the shield machine excavates by the excavation stroke length (Ls) is Q, The theoretical soil discharge volume is V1. When the shield machine excavates by the excavation stroke length (Ls), the measured amount of discharged soil measured by the discharged soil amount measuring means is V2 (V1 ≧ V2), The discrimination unit is When the difference (V1-V2) between the theoretical discharge amount V1 (= S × Ls + Q) and the measured discharge amount V2 is equal to or less than a first predetermined value α (V1-V2≦α), it is determined that the excavated soil is mainly clayey soil, The soil removal system of claim 3, wherein if the difference (V1-V2) is greater than or equal to a second predetermined value β (>α) that is greater than the first predetermined value α (V1-V2≧β), the excavated soil is determined to be mainly sandy soil.

5. A method for transporting soil and sand generated by excavation using a shield machine and an additive for excavation that promotes plastic fluidization of the excavated soil and sand by a pressure pump through a pressure pipe, a pressure detection step of detecting a pressure of the pressure pump and / or the pressure pipe; A control step of controlling an injection amount of a pressure-feeding additive to the pressure-feeding pipe to reduce a pressure-feeding resistance based on the pressure detected in the pressure detection step; A method for removing soil and sand comprising the steps of:

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