JP4770471B2 - Shield machine design method - Google Patents

Description

  The present invention relates to a shield machine design method.

  In recent years, when constructing underground structures in urban areas, shield construction methods have been adopted in order to smoothly perform construction on roads with heavy traffic and reduce the impact of construction on surrounding residents. It is often used during tunnel construction. In addition, because it is difficult to secure a sufficient work base area on the ground in urban areas, construction using earth pressure type shields that require a small area for equipment placement space compared to muddy water type shields that require a large area for equipment placement space. Needs are growing.

  However, the excavation method using earth pressure type shields has not established a method for grasping the plastic flow state of excavated soil in the chamber, which is important for maintaining the stability of the face, and it is difficult to completely suppress ground deformation. For this reason, it was rarely applied to a shield method with a large cross section. As shown in FIG. 21, the plastic fluidization is a state where the shear stress generated in the excavated earth and sand exceeds a certain value (τ 0), generates a shear rate, and flows. Here, the shear stress is a force per unit area that causes a flow having a relative speed difference in the excavated soil (hereinafter referred to as shear strain), and the shear rate is a change in shear strain per unit time. Is the strain rate.

  In order to grasp the plastic flow state of excavated sediment in the chamber, for example, Patent Document 1 discloses a measuring device for measuring the flow state of excavated sediment. In addition, this Patent Document 1 also discloses an example in which the flow analysis method in the chamber shown in Non-Patent Documents 1 and 2 is applied to an actual shield machine.

  This measuring device includes a rotating plate installed in the chamber and a motor for driving the rotating plate, and the motor is driven to rotate the rotating plate by a predetermined angle so that the rotation resistance is rotated at the maximum position. The direction orthogonal to the main surface of the plate is the flow direction of the excavated earth and sand, and a value corresponding to the rotational torque at that time is calculated as the flow velocity.

And by the flow analysis method shown in Non-Patent Documents 1 and 2, flow analysis of excavated sediment in the chamber is performed for each of a plurality of geological conditions such as sand ground and viscosity ground, and the flow direction in each case Estimate the flow velocity, etc., and check the flow direction and flow velocity estimated from the flow analysis against the flow direction and flow velocity calculated by the measurement device described above, and select the flow analysis result with the best correlation. This is the flow state at the measurement point.
JP-A-2005-90174 "Tunnel and underground" August 1994, pages 35-39 "Flow analysis of mud and mud water in shield chamber" “Obayashi Institute of Technology Report” No. 48 August 1994 "Drilling sediment flow analysis in shield chamber"

  However, in the flow analysis described in Patent Document 1, only the flow direction and flow velocity in the chamber are estimated, and there is a problem that the analysis regarding the shear rate, which is an index representing the plastic flow state in the chamber, has not been made.

  In addition, it is generally known that the stirring effect in the chamber differs depending on the installation position of the stirring mechanism such as an agitator, fixed blade, stirring device, etc. in the chamber, the number of installations, etc. There was a problem that there was no way to quantitatively confirm the difference. Therefore, the shield machine was designed based on the specifications of the shield machine applied to the similar soil in the past, and there was a problem that the optimum shield machine was not designed for the soil to be excavated. .

  Therefore, the present invention has been made in view of the conventional problems as described above, and grasps the flow state or plastic flow state of excavated sediment based on the specifications in the chamber of the shield machine by flow analysis, and proceeds with excavation. It is an object of the present invention to provide a design method for designing a shield machine based on specifications in a chamber in a flow state or plastic flow state that is optimal for the above.

In order to achieve the above object, a shield machine design method according to the present invention includes a stirring mechanism for stirring excavated earth and sand flowing into a chamber, and a soil removing mechanism for discharging the excavated earth and sand. In the design method, the step of setting the specifications of the stirring mechanism and the soil removal mechanism, the step of modeling the inside of the chamber based on the set specification, and the inside of the chamber based on the modeled model Analyzing the flow state of the chamber, simulating the flow rate and shear rate of the excavated sediment throughout the chamber, visualizing the flow rate and shear rate, and excavating the entire chamber based on the visualized results The process of confirming the flow state or plastic flow state of earth and sand, and when the flow state or plastic flow state in the chamber is appropriate in the confirmation Characterized by designing the shield machine to meet the specification that the set (the first invention).
According to the shield machine design method of the present invention, it is possible to grasp the flow state or plastic flow state of excavated soil based on the specifications of the stirring mechanism and the soil discharge mechanism of the shield machine. And, by designing the shield machine based on the specifications of the stirring mechanism and soil removal mechanism that will be in an appropriate flow state or plastic flow state, it is possible to ensure that the chamber is in a flow state or plastic flow state during tunnel excavation It becomes.

According to a second aspect of the present invention, there is provided a method for designing an earth pressure shield machine comprising an earth pressure shield machine including an agitation mechanism for agitating excavated earth and sand flowing into a chamber and an earth discharge mechanism for discharging the excavated earth and sand. In the design method, the steps of setting the specifications in the chamber by setting the specifications of the stirring mechanism and the soil removal mechanism, respectively, the step of modeling the inside of the chamber based on the set specifications, and the modeling A flow analysis of the flow state in the chamber based on the model, a step of simulating the flow rate and shear rate of the excavated sediment in the entire chamber, a step of visualizing the flow rate and the shear rate, and the visualization result And confirming the plastic flow state of the entire excavated earth and sand in the chamber, and if the plastic flow state in the chamber is appropriate in the confirmation Characterized by designing the shield machine to meet the specification that said setting.
According to the earth pressure shield machine design method according to the present invention, it is possible to grasp the plastic flow state of excavated earth and sand based on the specifications of the stirring mechanism and the soil discharge mechanism of the earth pressure shield machine. Then, by designing the earth pressure shield machine based on the specifications of the stirring mechanism and the soil discharging mechanism that are in an appropriate plastic flow state, the inside of the chamber can be reliably put into a plastic flow state during tunnel excavation.

According to a third invention, in the second invention, from the step of setting a plurality of the specifications and modeling the inside of the chamber based on each of the plurality of specifications to the step of confirming the flow state or plastic flow state In the confirmation, out of the specifications in which the plastic flow state in the plurality of chambers is appropriate, the optimum specification for the excavation of the earth pressure type shield machine is selected, and the earth pressure type so as to satisfy the selected optimum specification. It is characterized by designing a shield machine.
According to the earth pressure type shield machine design method according to the present invention, it is possible to compare a plurality of appropriate plastic flow states and select the specifications of the agitation mechanism and the soil removal mechanism that are optimal for excavation. And by designing earth pressure shield machine that satisfies the specifications of this optimum agitation mechanism and soil removal mechanism, it is possible to safely excavate with the earth pressure shield machine even with large and medium cross-sections with the face stable. It becomes. Furthermore, not only a circular cross section but also a cross section other than a circular shape such as a rectangle can be excavated.

According to a fourth invention, in the second or third invention, when the plastic flow state in the chamber is inappropriate in the confirmation, the specification is changed, and the earth pressure type shield is changed again based on the changed specification. From the step of modeling the inside of the chamber of the machine to the step of confirming the plastic flow state is carried out.
According to the earth pressure shield machine design method according to the present invention, the specifications of the agitation mechanism and the soil removal mechanism can be changed after confirming the plastic flow state. It is possible to feed back the changes.

In a fifth invention according to any one of the second to fourth inventions, the confirmation is performed by evaluating a relationship between the flow velocity and the shear rate, and a relationship between the flow velocity and the shear velocity is within a predetermined range. If it is, it is appropriate, and if it is not within the predetermined range, it is determined that it is inappropriate.
According to the earth pressure shield machine design method of the present invention, since the relationship between the flow velocity and the shear rate is evaluated in the figure, it is determined whether or not the relationship between the flow velocity and the shear rate is within a predetermined range. It is possible to easily determine. Therefore, even if it is not a person skilled in earth pressure type shield construction method, it can judge.

According to a sixth aspect of the present invention, there is provided a muddy water shield machine design method comprising: a stirring mechanism for agitating excavated earth and sand flowing into a chamber; and a mud type shield machine provided with a soil discharging mechanism for discharging the excavated earth and sand. In the design method, a step of setting specifications of the agitation mechanism and the soil removal mechanism, a step of modeling the inside of the chamber based on the set specification, and a step of modeling the inside of the chamber based on the modeled model Analyzing the flow state, simulating the flow rate and shear rate of the excavated sediment in the entire chamber, visualizing the flow rate and the shear rate, and excavating sediment in the entire chamber based on the visualized results The process of confirming the flow state of the shield and, if the flow state in the chamber is appropriate in the confirmation, the shield is set so as to satisfy the set specifications. Characterized by designing.
According to the method for designing a muddy water shield machine according to the present invention, it is possible to grasp the flow state of excavated earth and sand based on the specifications of the stirring mechanism and the soil discharge mechanism of the muddy water shield machine. And, by designing the muddy water type shield machine based on the specifications in the chamber that is in an appropriate fluidized state, it is possible to ensure that the chamber is fluidized during tunnel excavation.

  As described above, according to the shielding machine design method of the present invention, in order to design a shielding machine based on the flow analysis results, a shielding machine for a circular medium, large cross section, and rectangular cross section is designed. can do. In addition, since the flow state or the plastic flow state is confirmed in advance by the flow analysis, the face can be safely excavated in a stable state. Furthermore, since the flow state and the plastic flow state can be confirmed by the flow analysis, the muddy water type shield machine and the earth pressure type shield machine can be designed.

  Hereinafter, a preferred embodiment of a design method for a shield machine according to the present invention will be described in detail with reference to the drawings. For the convenience of understanding the invention, in this embodiment, the specifications of the chamber of the earth pressure type shield machine for excavating the ground by pressurizing the mud pressure over the entire face, the cutter of the stirring mechanism, the stirring device, the fixed blade In the case of providing an agitator (hereinafter referred to as CASE 1), in the case of providing a cutter, a stirring device and a fixed blade (hereinafter referred to as CASE 2), in the case of providing a cutter and a stirring device (hereinafter referred to as CASE 3), only the cutter is provided. Although the case (hereinafter referred to as CASE 4) will be described, the devices provided in the chamber are not limited to these, and various devices such as a soil removal mechanism can be installed.

  FIG. 1 is a cross-sectional view of a CASE 1 earth pressure shield machine according to the first embodiment of the present invention, and FIG. 2 is a view taken along the arrow A-A ′ of FIG. 1.

  As shown in FIGS. 1 and 2, the earth pressure shield machine 1 connects the hood part 3 for excavating the face at the front part in the traveling direction, the tail part for lining at the rear part, and the hood part 3 and the tail part. In addition, the girder portion 5 is provided with propulsion equipment and the like, and includes a skin plate 9 made of a rectangular cylindrical steel shell for protecting each portion described above against a load acting from the outside.

  The front part of the earth pressure type shield machine 1 transmits a cutter 11 having a cutter bit on the front side of the earth pressure type shield machine 1, a drive source 13 for driving the cutter 11, and the driving force of the drive source 13 to the cutter 11. A rotating shaft 15, a chamber 19 sealed with a partition wall 17 and a cutter 11 for applying and maintaining a constant pressure on the excavated earth and sand, and a soil discharging mechanism 21 for discharging the excavated earth and sand from the chamber 19. , A stirring device 23 for agitating and kneading the excavated earth and sand in the chamber 19, a fixed blade 24 for enhancing the kneading effect of the excavated earth and mud (bubble) material, and the flow direction of the excavated earth and sand in the chamber 19 And a measuring device 25 for estimating the flow velocity.

  An agitator 27 is provided on the outer peripheral surface of the rotating shaft 15 so as to protrude into the chamber 19, and this agitator 27 is rotated independently of the cutter 11 by a drive motor 29 installed in the girder unit 5. Driven.

  The agitation device 23 is concentric with the central axis of the earth pressure shield machine 1 and is disposed on three circumferences having different diameters at predetermined intervals in the circumferential direction, and is projected into the chamber 19 so as to protrude into the chamber 19. Multiple units are provided on the back side.

  The fixed wings 24 are concentric with the central axis of the earth pressure shield machine 1 and are arranged on three circumferences having different diameters at predetermined intervals in the circumferential direction, and project into the chamber 19 so as to protrude into the chamber 19. Multiple units are provided on the front side.

  The measuring device 25 transmits a plate-shaped rotating plate 31 disposed so as to face the flow direction of the excavated sediment, a motor 33 for driving the rotating plate 31, and a driving force of the motor 33 to the rotating plate 31. A rod 35, a current measuring device 37 for measuring the current value of the motor 33, an angle detector 39 for detecting the rotation angle of the rotating plate 31, and the rotating plate 31 in the direction of the central axis of the earth pressure shield machine 1 And a cylinder 41 for enabling movement. A plurality of measuring devices 25 are arranged at a predetermined interval in the circumferential direction on a concentric circle with the central axis of the earth pressure shield machine 1 and are provided at positions where mutual interference with the stirring device 23 and the agitator 27 is avoided. In addition, in this embodiment, although the measuring apparatus 25 demonstrated the method of installing in the circumferential direction at predetermined intervals on the concentric circle with the center axis | shaft of the earth pressure type shield machine 1, it is not limited to this position. It can be installed at any position.

  The rotating plate 31 of the measuring device 25 is a rectangular flat plate and is arranged so that the main surface of the flat plate faces the flow direction of excavated earth and sand flowing in the chamber. When the excavated sediment flows in the chamber 19, the main surface of the rotating plate 31 rotates around an axis parallel to the central axis of the earth pressure shield machine 1.

FIG. 3 is a flowchart showing a procedure for determining the specifications of the earth pressure shield machine 1 according to the present embodiment. Moreover, FIG. 4 is a figure which shows the particle size curve of the ground which concerns on this embodiment.
In S10 of FIG. 3, the excavation condition and the soil condition when excavating the ground with the earth pressure shield machine 1 are set. In the present embodiment, for example, a ground having a particle size curve as shown in FIG. 4 is excavated.
And in S12 of FIG. 3, the specification of the stirring mechanism is set. In the present embodiment, as shown in FIG. 1, a cutter 11, a stirring device 23, a fixed blade 24, and an agitator 27 are provided in a chamber 19 of CASE 1.

  FIG. 5 is a diagram modeling the inside of the chamber 19 of the CASE 1 according to the present embodiment. In S20 of FIG. 3, the inside of the chamber 19 of CASE 1 is modeled as shown in FIG. 5 by the method disclosed in Non-Patent Documents 2 and 3 described above.

  FIG. 6 is a diagram showing input conditions for flow analysis according to the present embodiment. In S22 of FIG. 3, based on the modeled model and input conditions (shown later), flow analysis of the excavated sediment is performed by the methods disclosed in Non-Patent Documents 2 and 3 described above, and the flow velocity and shear rate are determined. Simulate.

  The basic equation used for the flow analysis is an incompressible Navier-Stokes equation that considers density stratification, assuming that the excavated sediment in the chamber 19 is a fluid composed of natural soil and mud (bubble) material. . In addition, the dynamic multi-block method was applied to complicated moving boundary portions such as the rotation of the cutter 11.

  In the present embodiment, as shown in FIG. 6, for example, the input conditions for the flow analysis are as follows: the rotational speed of the agitator 27 is 1.365 rpm, the rotational speed of the cutter 11 is 0.46 rpm, and the excavation speed of the earth pressure shield machine 1 is 20 mm / min. Furthermore, as input conditions for flow analysis, the fluid density calculated from the volume occupancy ratio between the natural ground density and the mud (bubble) material density, the viscosity formula for each soil, and the like are also input.

  7 and 8 are a flow velocity distribution diagram and a shear velocity distribution diagram of excavated sediment in all the CASE chambers 19 according to the present embodiment. 7 and 8 show analysis results in the vicinity of the cutter face, in the vicinity of the center of the chamber 19 and in the vicinity of the partition wall 17. In the present embodiment, the vicinity of the cutter face, the vicinity of the center of the chamber 19, and the vicinity of the partition wall 17 are, for example, 1.7 m, 0.9 m, and 0.45 m ahead of the partition wall 17, respectively.

  In S34 of FIG. 3, the flow velocity and the shear velocity are visualized as shown in FIGS. The flow velocity is displayed as a vector, and the flow velocity and flow direction of the excavated sediment are displayed according to the length and direction of the arrows. Also, the shear rate is displayed as a scalar, and the magnitude of the speed is displayed according to the color density.

  The excavated earth and sand in the chamber 19 is given a flow velocity by the rotation of the cutter 11, and shear stress is generated by the stirring device 23 and the agitator 27. When the excavated sediment in the chamber 19 is in a plastic flow state, it is presumed that a shear rate is generated when shear stress is generated.

  As shown in CASE 1 in FIG. 7 and CASE 1 in FIG. 8, in the present embodiment, in the transverse direction, the distribution of the flow velocity and the shear velocity is around the outer periphery of the earth pressure shield machine 1, around the agitator 27, and around the rotating shaft 15. In, it is not uniform, and different states are confirmed. Also in the longitudinal direction, the distribution of flow velocity and shear velocity is not uniform in the vicinity of the cutter face, near the center of the chamber 19 and near the partition wall 17, and different states are confirmed.

  FIG. 9 is a diagram showing a flow state of excavated earth and sand according to the present embodiment. As shown in FIG. 9, focusing on the relationship between the flow velocity and the shear rate, and classifying the flow state of the excavated soil in the chamber 19, the region I has an appropriate flow velocity and shear rate, It is presumed that the excavated sediment in the chamber 19 is plastic fluidized. Further, since the region II has a low flow velocity and a low shear rate, the excavated sediment in the chamber 19 is not in a state of plastic fluidization, or the excavated sediment is in a state in which it is difficult to stir. Guessed. And in the area | region III, since the flow rate is small and the shear rate is large, it is estimated that the excavated sediment in the chamber 19 is in a very high fluidity state. In the region IV, since the flow velocity is high and the shear rate is low, it is presumed that the excavated soil in the chamber 19 is not plastically fluidized or is a portion with little stirring effect.

  10, 11, and 12 are diagrams showing the flow state of excavated soil near the cutter face, near the center of the chamber 19, and near the partition wall 17 according to the present embodiment, with the vertical axis representing the flow velocity and the horizontal axis representing the logarithm. It's a drag speed. In addition, the transverse region is defined as (1) agitator 27 region (0 to 1 / 3R, R is a shield radius), (2) cutter support portion (1 / 3R to 2 / 3R), (3) outer peripheral portion ( 2 / 3R to 1R), and the relationship between the flow rate and the shear rate was shown.

  In S36 of FIG. 3, the relationship between the flow velocity and the shear velocity in the vicinity of the cutter face, in the vicinity of the center of the chamber 19 and in the vicinity of the partition wall 17 is evaluated. As shown in FIGS. 10 to 12, the relationship between the flow velocity and the shear velocity is near the center of the graph in the vicinity of the center of the chamber 19 than in the vicinity of the cutter face, and in the vicinity of the partition wall 17 near the center of the chamber 19. This is a state in which the excavated earth and sand is plastically fluidized by the effects of the agitator 23 and the agitator 27 when it moves from the vicinity of the cutter face to the vicinity of the partition wall 17. In consideration of the fact that the soil removal situation was good and the face was stable in the construction work, this flow analysis result simulates the case where the sediment in the chamber 19 is appropriately plasticized and analyzed. It shows that the accuracy is high.

Next, the case where the specification of the stirring mechanism in the chamber 19 is changed to CASE 2 will be described.
FIG. 13 is a cross-sectional view of the earth pressure type shield machine 1 of CASE 2 according to the present embodiment. In S12 of FIG. 3, as shown in FIG. 13, a cutter 11, a stirring device 23, and a fixed blade 24 are provided in the chamber 19 of CASE 2.
FIG. 14 is a diagram modeling the inside of the chamber 19 of CASE 2 according to the present embodiment. As shown in FIG. 14, in S20 of FIG. 3, the inside of the chamber 19 of the earth pressure type shield machine 1 of CASE 2 is modeled similarly to the case of CASE 1.

Then, in S22 of FIG. 3 again, based on the CASE2 model and the same input conditions as CASE1, the flow analysis is performed to simulate the flow velocity and shear velocity.
Then, again, in S34 of FIG. 3, the flow velocity and the shear velocity are visualized as shown in CASE 2 of FIG. 7 and CASE 2 of FIG.
3 again, in the case of CASE 2 as in CASE 1, the relationship between the flow velocity and the shear velocity in the vicinity of the cutter face, in the vicinity of the center of the chamber 19 and in the vicinity of the partition wall 17 is evaluated (not shown). Check the plastic flow state.

Next, the case where the specification of the stirring mechanism in the chamber 19 is changed to CASE 3 will be described.
15 is a sectional view of the earth pressure type shield machine 1 of CASE 3 according to the present embodiment, and FIG. 16 is a view taken along the line BB ′ of FIG.
In S12 of FIG. 3, as shown in FIGS. 15 and 16, a cutter 11 and a stirring device 23 are provided in the chamber 19 of CASE 3.

  FIG. 17 is a diagram modeling the inside of the chamber 19 of the CASE 3 according to the present embodiment. As shown in FIG. 17, in S20 of FIG. 3, the inside of the chamber 19 of the earth pressure type shield machine 1 of CASE 3 is modeled in the same manner as the case of CASE 1.

Then, in S22 of FIG. 3 again, based on the same input conditions as the CASE3 model, CASE1 and CASE2, the flow analysis is performed to simulate the flow velocity and shear velocity.
Then, again in S34 of FIG. 3, the flow velocity and the shear velocity are visualized as shown in CASE 3 of FIG. 7 and CASE 3 of FIG.
3 again, in the case of CASE 3 as in CASE 1 and 2, the relationship between the flow velocity and the shear velocity in the vicinity of the cutter face, in the vicinity of the center of the chamber 19, and in the vicinity of the partition wall 17 is evaluated (see the figure). No), check the plastic flow state.

Finally, the case where the specification of the stirring mechanism in the chamber 19 is changed to CASE4 will be described.
FIG. 18 is a cross-sectional view of the earth pressure type shield machine 1 of CASE 4 according to the present embodiment, and FIG. 19 is a view taken along the line CC ′ of FIG.
In S12 of FIG. 3, only the cutter 11 is provided in the chamber 19 of the CASE 4 as shown in FIGS.
FIG. 20 is a diagram modeling the inside of the chamber 19 of the CASE 4 according to the present embodiment. As shown in FIG. 20, in S20 of FIG. 3, the inside of the chamber 19 of the earth pressure type shield machine 1 of CASE 4 is modeled in the same manner as in the case of CASE 1.

Then, in S22 of FIG. 3 again, based on the same input conditions as the CASE4 model, CASE1, CASE2, and CASE3, the flow analysis is performed to simulate the flow velocity and shear velocity.
Then, again, in S34 of FIG. 3, the flow velocity and the shear velocity are visualized as shown in CASE 4 in FIG. 7 and CASE 4 in FIG.
3 again, in the case of CASE 4 as in the case of CASE 1 to 3, the relationship between the flow velocity and the shear velocity in the vicinity of the cutter face, in the vicinity of the center of the chamber 19 and in the vicinity of the partition wall 17 is evaluated (illustrated). No), check the plastic flow state.

  When the plastic flow states of these CASEs 1 to 4 are confirmed, the relationship between the flow velocity and the shear rate is in the range I described above, and the plastic flow state of only CASE when the plastic flow state is appropriate is shown in FIG. Compare at S40.

Then, the optimum plastic flow state is compared with each other, and the optimum plastic flow state for excavation is selected, and the specifications of the stirring mechanism in this plastic flow state are determined. In this embodiment, for example, a stirring mechanism in which the cutter 11, the stirring device 23, the fixed blade 24, and the agitator 27 are provided in the chamber 19 of CASE 1 is selected.
In S42 of FIG. 3, so as to satisfy the specifications of the selected stirring mechanism, for example, the necessary torque of the cutter 11 of the earth pressure type shield machine 1, selection of a motor for outputting the torque, selection of a motor for the agitator 27, The earth pressure type shield machine 1 such as a seal structure around the chamber 19 is designed.

  According to the design method of the earth pressure type shield machine 1 in the present embodiment described above, it is possible to grasp the plastic flow state of excavated earth and sand based on the specifications in the chamber 19 of the earth pressure type shield machine 1. And by designing the earth pressure type shield machine 1 based on the specification in the chamber 19 that is in an appropriate plastic flow state, the inside of the chamber 19 can be reliably put into a plastic flow state during tunnel excavation.

  In addition, it is possible to compare a plurality of appropriate plastic flow states and to select a specification in the chamber 19 that is most suitable for excavation. Then, by designing the earth pressure shield machine 1 that satisfies the specifications in the optimum chamber 19, it is possible to safely excavate the face with the earth pressure shield machine 1 in a stable state even with large and medium cross sections. Become. Furthermore, not only a circular cross section but also a cross section other than a circular shape such as a rectangle can be excavated.

  Since the specification in the chamber 19 can be changed after the plastic flow state is confirmed, the flow analysis result can be fed back to the change in the specification in the chamber 19.

  Furthermore, since the relationship between the flow rate and the shear rate is evaluated by the chart, it is possible to easily determine whether or not the relationship between the flow rate and the shear rate is within a predetermined range. Therefore, even if it is not a person skilled in earth pressure type shield construction method, it can judge.

  In the present embodiment, the method of using the stirring device 23 of the stirring mechanism, the fixed blade 24, and the agitator 27 in setting the specifications in the chamber 19 has been described. However, the devices provided in the chamber 19 are not limited to these. For example, it is possible to install other devices such as a soil removal mechanism. And it is possible to confirm the influence regarding a plastic flow state in all the apparatuses provided in the chamber 19. Further, in the case of performing a flow analysis on the soil removal mechanism 21, it is possible to set specifications for the diameter, installation position, number of installations, and the like of the soil removal mechanism.

  In addition, in this embodiment, in order to design the earth pressure type shield machine 1, the method of analyzing the plastic flow state in the chamber 19 and simulating the flow velocity and the shear velocity has been described. However, the present invention is not limited to this. It is also possible to design a muddy water shield machine for excavating the ground by analyzing the flow state in the chamber, simulating the flow velocity and applying muddy water pressure to the entire face.

It is sectional drawing of the earth pressure type shield machine of CASE1 which concerns on 1st embodiment of this invention. It is an A-A 'arrow line view of FIG. It is a flowchart which shows the procedure for determining the specification of the earth pressure type shield machine which concerns on this embodiment. It is a figure which shows the particle size curve of the ground which concerns on this embodiment. It is the figure which modeled the inside of the chamber of CASE1 concerning this embodiment. It is a figure which shows the input conditions of the flow analysis which concerns on this embodiment. It is a flow velocity distribution map of excavated sediment in all CASE chambers according to the present embodiment. It is a shear rate distribution map of excavated earth and sand in all CASE chambers according to the present embodiment. It is a figure which shows the flow state of the excavation earth and sand which concerns on this embodiment. It is a figure which shows the flow state of the cutter face vicinity which concerns on this embodiment. It is a figure which shows the flow state of the chamber center vicinity which concerns on this embodiment. It is a figure which shows the flow state of the partition vicinity which concerns on this embodiment. It is sectional drawing of the earth pressure type shield machine of CASE2 which concerns on this embodiment. It is the figure which modeled the inside of the chamber of CASE2 concerning this embodiment. It is sectional drawing of the earth pressure type shield machine of CASE3 which concerns on this embodiment. It is a B-B 'arrow line view of FIG. It is the figure which modeled the inside of the chamber of CASE3 concerning this embodiment. It is sectional drawing of the earth pressure type shield machine of CASE4 which concerns on this embodiment. It is a C-C 'arrow line view of FIG. It is the figure which modeled the inside of the chamber of CASE4 concerning this embodiment. It is a figure which shows the plastic flow state of excavated earth and sand.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Earth pressure type shield machine 3 Hood part 5 Girder part 9 Skin plate 11 Cutter 13 Driving source 15 Rotating shaft 17 Bulkhead 19 Chamber 21 Earth removal mechanism 23 Stirring device 24 Fixed blade 25 Measuring device 27 Agitator 29 Driving motor 31 Rotating plate 33 Motor 35 Rod 37 Current measuring device 39 Angle detector 41 Cylinder

Claims (6)

In a design method of a shield machine provided with a stirring mechanism for stirring the excavated earth and sand flowing into the chamber and a soil discharging mechanism for discharging the excavated earth and sand,
Setting the specifications of the stirring mechanism and the soil removal mechanism,
Modeling the interior of the chamber based on the set specifications;
Analyzing the flow state in the chamber based on the modeled model, and simulating the flow rate and shear rate of the excavated sediment throughout the chamber;
Visualizing the flow rate and the shear rate;
A step of confirming the flow state or plastic flow state of the excavated sediment in the entire chamber based on the visualized result;
In the confirmation, when the flow state or plastic flow state in the chamber is appropriate, the shield machine is designed so as to satisfy the set specifications. In the design method of the earth pressure type shield machine provided with the stirring mechanism for stirring the excavated earth and sand flowing into the chamber and the earth discharging mechanism for discharging the excavated earth and sand,
Setting the specifications in the chamber by setting the specifications of the stirring mechanism and the soil removal mechanism, respectively;
Modeling the interior of the chamber based on the set specifications;
Analyzing the flow state in the chamber based on the modeled model, and simulating the flow rate and shear rate of the excavated sediment throughout the chamber;
Visualizing the flow rate and the shear rate;
Confirming the plastic flow state of the excavated sediment throughout the chamber based on the visualized results;
In the confirmation, when the plastic flow state in the chamber is appropriate, the shield machine is designed so as to satisfy the set specifications. Set multiple specifications,
Based on each of the plurality of specifications, from the step of modeling the inside of the chamber to the step of confirming the flow state or plastic flow state,
Among the specifications in which the plastic flow state in the plurality of chambers is appropriate in the confirmation, select the specifications that are optimal for the excavation of the earth pressure shield machine,
3. The earth pressure shield machine design method according to claim 2, wherein the earth pressure shield machine is designed to satisfy the selected optimum specification. If the plastic flow state in the chamber is inappropriate in the confirmation, change the specification,
4. The earth pressure type according to claim 2, wherein the process from the step of modeling the inside of the chamber of the earth pressure shield machine again to the step of confirming the plastic flow state is performed based on the changed specifications. How to design a shield machine. The confirmation
Evaluate the relationship between the flow rate and the shear rate, and if the relationship between the flow rate and the shear rate is within a predetermined range, it is appropriate. If it is not within the predetermined range, it is inappropriate. It determines with these, The design method of the earth pressure type shield machine in any one of Claims 2-4 characterized by the above-mentioned. In a method for designing a muddy water shield machine comprising an agitation mechanism for agitating excavated earth and sand flowing into the chamber and an earth discharging mechanism for discharging the excavated earth and sand,
Setting the specifications of the stirring mechanism and the soil removal mechanism,
Modeling the interior of the chamber based on the set specifications;
Analyzing the flow state in the chamber based on the modeled model, and simulating the flow rate and shear rate of the excavated sediment throughout the chamber;
Visualizing the flow rate and the shear rate;
Confirming the flow state of the excavated sediment throughout the chamber based on the visualized results;
In the confirmation, when the flow state in the chamber is appropriate, the shielding machine is designed so as to satisfy the set specification.