Tunnel excavator system

Abstract

To provide at least one of a planned excavation alignment determination system and a jack control system, capable of easily and reliably correcting an excavation position of a tunnel excavator even if it deviates from a planned alignment.SOLUTION: A planned excavation alignment determination system comprises a planned alignment memory unit 70 which stores a planned alignment of a tunnel excavator, a deviation amount calculation unit 72 which calculates a deviation amount of an excavation position from the planned alignment, a corrected alignment memory unit 73 which stores corrected alignment that corrects the excavation position of the tunnel excavator to align with the planned alignment, and a corrected alignment selection unit 74 which selects one of a plurality of corrected alignment based on the deviation amount. The corrected alignment indicates the relationship between the deviation amount and a corrected excavation distance, which is an excavation distance from the excavation position to a target position on the planned alignment where the deviation amount is zero, and is a curve which monotonically increases in the deviation amount with respect to the corrected excavation distance. A plurality of corrected alignment are set in order of increasing corrected excavation distance for the same deviation amount except for the target position.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a tunnel boring machine system for determining a corrective alignment for correcting deviation from a planned alignment when a tunnel boring machine excavates and for excavating the tunnel, i.e., at least one of a planned excavation alignment determination system and a jack control system. [Background technology]

[0002] When a tunnel boring machine such as a shield machine excavates the ground, the excavation position may deviate from the planned alignment. In order to excavate a tunnel according to plan, it is necessary to correct any deviations in the excavation position made by the tunnel boring machine and return it to the planned alignment as it continues excavating.

[0003] Patent document 1 discloses an excavation management system that determines the position of a shield tunneling machine through surveying, compares the survey data with the planned route to determine the amount of deviation, and corrects the route so that the amount of deviation is zero in the nth ring from the current ring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-296679 Summary of the Invention [Problem to be solved by the invention]

[0005] When making such route corrections, the tunnel alignment will vary depending on the person making the corrections due to differences in personal skill and experience, etc. Also, depending on conditions such as soil quality, the corrected plan to return to the planned route may not be close enough or may be too close, and the correction plan must be made again, but even in this case, variations due to personal differences will occur.

[0006] In addition, when implementing a revised plan, the tunnel boring machine's propulsion jacks are controlled to excavate the tunnel, but the control methods for each propulsion jack vary depending on the individual's skill and experience, resulting in variation.

[0007] The problem that the present invention aims to solve is to provide at least one of a planned excavation linearity determination system for a tunnel excavation machine and a jack control system which can easily and reliably correct the excavation position of the tunnel excavation machine deviating from the planned linearity without variation due to individual differences. [Means for solving the problem]

[0008] means for calculating the deviation of the excavation position from the planned linearity; a correction linearity storage unit for storing the planned linearity along which the tunnel excavation machine will excavate; a deviation amount calculation unit for calculating the deviation amount of the excavation position from the planned linearity; a correction linearity storage unit for storing a correction linearity that corrects the excavation position of the tunnel excavation machine so that it follows the planned linearity; and the correction linearity stored in the correction linearity storage unit indicates the relationship between the deviation amount and a corrected excavation distance, which is the excavation distance from the excavation position to a target position on the planned linearity at which the deviation amount is zero, and is a curve in which the deviation amount increases monotonically with respect to the corrected excavation distance, and a plurality of correction linearity are set in order of increasing corrected excavation distance for the same deviation amount except for the target position, and a correction linearity selection unit for selecting one of the plurality of correction linearity based on the deviation amount.

[0009] Means 2 is a system for determining the planned excavation linearity of a tunnel boring machine described in Means 1, characterized in that the corrected linearity is a curve in which the ratio of the corrected excavation distance to the deviation amount becomes larger the closer the corrected linearity is to the target position.

[0010] Means 3 is a system for determining a planned excavation alignment of a tunnel boring machine as described in Means 1 or 2, characterized in that when the deviation amount calculated by the deviation amount calculation unit exceeds a threshold value, if the deviation amount is greater than the target deviation amount when excavating along the previously selected corrected alignment, the corrected alignment selection unit selects a corrected alignment having a smaller corrected excavation distance for the same deviation amount than the previously selected corrected alignment, if the deviation amount is the same as the target deviation amount when excavating along the previously selected corrected alignment, the corrected alignment selection unit selects the previously selected corrected alignment, and if the deviation amount is smaller than the target deviation amount when excavating along the previously selected corrected alignment, the corrected alignment selection unit selects a corrected alignment having a larger corrected excavation distance for the same deviation amount than the previously selected corrected alignment.

[0011] Means 4 is a jack control system that controls valves of multiple propulsion jacks possessed by a tunnel boring machine, and includes a resultant force point calculation unit that calculates a jack resultant force point of the propulsion jack based on a correction angle, and a valve opening calculation unit that calculates an opening degree of the valve of the propulsion jack based on the jack resultant force point calculated by the resultant force point calculation unit. The valve opening calculation unit calculates a valve opening change amount that is the amount of change in valve opening when the position where the propulsion jack is placed changes by 1 degree from the jack resultant force point angle, which is the angle of a straight line connecting the position where the propulsion jack is placed and the center point, based on the maximum valve opening and minimum valve opening set for the valve and the resultant force point distance, which is the distance from the center point to the jack resultant force point, calculates an angle difference that is the difference between the angle of the straight line connecting the position where the propulsion jack is placed and the center point, and the jack resultant force point angle, and calculates the opening degree of the valve of the propulsion jack based on the valve opening change amount and the angle difference.

[0012] Means 5 is a jack control system that controls valves of a plurality of propulsion jacks of a tunnel boring machine, the plurality of propulsion jacks being divided into four or more blocks in groups, propulsion jacks in the same block being controlled by the same block valve, the system including a resultant force point calculation unit that calculates a jack resultant force point of the propulsion jacks based on a correction angle, and an individual jack valve opening calculation unit that calculates an opening degree of each valve of the propulsion jacks when the propulsion jacks are individually controlled by valves based on the jack resultant force point calculated by the resultant force point calculation unit. and a block valve opening calculation unit that calculates the opening of the block valve for each of the blocks, wherein the individual jack valve opening calculation unit calculates a valve opening change amount that is a change amount of the valve opening when the position where the propulsion jack is placed changes by 1 degree from a jack resultant force point angle that is the angle of a straight line connecting the position where the propulsion jack is placed and the center point, based on a maximum valve opening and a minimum valve opening that are set for the valve and a resultant force point distance that is a distance from a center point to the jack resultant force point, and calculates a valve opening change amount that is a change amount of the valve opening when the position where the propulsion jack is placed changes by 1 degree from a jack resultant force point angle that is the angle of a straight line connecting the position where the propulsion jack is placed and the center point, and calculates an angle difference which is the difference between the valve opening change amount and the angle difference, and calculates a valve opening of a propulsion jack based on the valve opening change amount and the angle difference, and the block valve opening calculation unit calculates a block total valve opening by summing the individual valve openings calculated by the individual jack valve opening calculation unit for each block, calculates an individual block jack resultant point which is the jack resultant point of each block based on the block total valve opening and the arrangement angle of the blocks, and calculates a total block jack resultant point which is the jack resultant point of all blocks based on the individual block jack resultant point. a block valve opening change amount, which is the amount of change in block valve opening when the position where the block is placed changes by 1 degree from an overall block jack resultant point angle, which is the angle of a line connecting the position where the block is placed and the center point, based on a maximum valve opening and a minimum valve opening set for the block valve and an overall block jack resultant point distance, which is the distance from a center point to the overall block jack resultant point, and a block angle difference, which is the difference between the angle of the line connecting the position where the block is placed and the center point and the overall block jack resultant point angle,The jack control system is characterized in that the opening degree of the block valve of the propulsion jack is calculated based on the block valve opening change amount and the block angle difference. Effect of the Invention

[0013] The system for determining the planned excavation alignment of a tunnel boring machine of the present invention can, when the excavation position of the tunnel boring machine deviates from the planned alignment, correct it along a correction alignment selected from a plurality of correction alignments set in advance based on the amount of deviation, so there is no variation due to differences in individual skill, experience, etc. Furthermore, the excavation position can be easily and reliably brought close to the planned alignment without the need for troublesome trajectory calculations.

[0014] In addition, if the correction curve is a curve in which the ratio of the corrected excavation distance to the deviation amount increases as it approaches the target position, the angle of the corrected alignment relative to the planned alignment becomes gradually gentler as it approaches the target position, so that the excavation position can be gradually and stably brought closer to the planned alignment.

[0015] In addition, when the deviation amount exceeds a threshold value, if the deviation amount is greater than the target deviation amount when excavating along the previously selected corrected alignment, the correction alignment selection unit selects a correction alignment having a smaller corrected excavation distance for the same deviation amount than the previously selected corrected alignment, and if the deviation amount is the same as the target deviation amount when excavating along the previously selected corrected alignment, it selects the previously selected corrected alignment, and if the deviation amount is smaller than the target deviation amount when excavating along the previously selected corrected alignment, it selects a correction alignment having a larger corrected excavation distance for the same deviation amount than the previously selected corrected alignment.In this way, only when a trajectory correction of the tunnel boring machine is necessary, can the optimal correction be made reliably without deviating significantly from the planned alignment.

[0016] The shield jack control system of the present invention can appropriately control each valve of the shield jack based on the resultant force point corresponding to the target correction angle, without variation due to differences in individual skill or experience. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of a tunnel boring machine according to a first embodiment. [Diagram 2] 1 is a block diagram of a system for determining an excavation plan linearity according to a first embodiment. FIG. [Diagram 3] FIG. 2 is a schematic diagram of a plurality of correction lines according to the first embodiment. [Figure 4] FIG. 4 is an explanatory diagram for determining a correction angle from a correction line shape according to the first embodiment. [Diagram 5] FIG. 4 is a diagram showing the relationship between the deviation amount and the correction angle for each corrected line shape according to the first embodiment. [Figure 6] FIG. 1 is a block diagram of a shield jack control system according to a first embodiment. [Figure 7] FIG. 2 is a layout diagram of a shield jack according to the first embodiment. [Figure 8] FIG. 4 is a diagram showing the jack angle, angle difference, valve opening difference, and valve opening of each shield jack according to the first embodiment. [Figure 9] 4 is a flowchart showing a process for determining a planned excavation line shape of the tunnel boring machine according to the first embodiment. [Figure 10] FIG. 11 is an arrangement diagram of a shield jack according to a second embodiment. [Figure 11] FIG. 11 is a block diagram of a shield jack control system according to a second embodiment. [Figure 12] FIG. 11 is a diagram showing the X- and Y-coordinates of a block jack resultant force point of each jack block and the X- and Y-coordinates of a total block jack resultant force point according to the second embodiment. [Figure 13] FIG. 11 is an arrangement diagram of a shield jack according to a third embodiment. [Figure 14] FIG. 13 is a diagram showing a display screen according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It goes without saying that the present invention is not limited to the embodiments.

[0019] [First embodiment] A first embodiment of the present invention will be described in detail below with reference to FIGS.

[0020] Figure 1 is a schematic diagram of a tunnel boring machine, Figure 2 is a block diagram of a system for determining the planned excavation linearity, Figure 3 is a schematic diagram of multiple corrected linearity, Figure 4 is an explanatory diagram for calculating the correction angle from the corrected linearity, Figure 5 is a diagram showing the relationship between the deviation amount and the correction angle for each corrected linearity, Figure 6 is a block diagram of a shield jack control system, Figure 7 is a diagram of the shield jack arrangement, Figure 8 is a diagram showing the jack angle, angle difference, valve opening difference, and valve opening of each shield jack, and Figure 9 is a flowchart of the process of determining the planned excavation linearity of a tunnel boring machine.

[0021] As shown in Figure 1, the tunnel boring machine of this embodiment is a shield machine 1, which has a circular rotating cutter 2 and a chamber 3 formed on the back side of the rotating cutter 2, and moves forward while cutting the natural ground by rotating the rotating cutter 2.

[0022] The excavated soil and sand are taken into the chamber 3 and discharged rearward via a mud discharge pipe or the like (not shown).

[0023] A surveying instrument 4 is mounted on the frame at the rear of the chamber 3, so that the excavation position and posture of the shield machine 1 can be grasped.

[0024] The rotating cutter 2 is provided on the front end surface of the shield tunneling machine 1, and rotates around the central axis of the shield tunneling machine 1 by driving a motor connected to the rotating cutter 2 via a gear or the like.

[0025] The rotating cutter 2 is provided with a plurality of cutter bits (not shown), and a tunnel is excavated by rotating the rotating cutter 2 and extending a plurality of (12 in this embodiment) shield jacks 5 to generate a reaction force.

[0026] The shield jacks 5 are arranged at equal intervals around the circumferential direction of the shield tunneling machine 1 (Figure 6), and the amount of expansion and contraction and pressure of the shield jacks 5 can be adjusted by appropriately opening and closing a valve 50 provided in the oil supply line of the shield jacks 5.

[0027] The shield tunneling machine 1 is provided with a control device 6 that controls its operation, and the control device 6 is composed of a computer and is connected to a display 60. The display 60 is a touch panel that displays operation buttons, calculation results, etc.

[0028] The control device 6 is equipped with a planned excavation linearity determination system 7 (Figure 2) that determines a corrected linearity to correct the deviation of the excavation position of the shield tunneling machine 1 from the planned linearity, and a shield jack control system 8 (Figure 5) that controls the shield jack 5 to correct the excavation direction of the shield tunneling machine 1 in accordance with the corrected linearity determined by the planned excavation linearity determination system 7.

[0029] As shown in Figure 2, the planned excavation linearity determination system 7 comprises a planned linearity memory unit 70 that stores the planned linearity along which the shield tunneling machine 1 will excavate, an excavation position memory unit 71 that stores the excavation position of the shield tunneling machine 1, a deviation amount calculation unit 72 that calculates the deviation amount of the excavation position from the planned linearity, a corrected linearity memory unit 73 that stores a corrected linearity that corrects the excavation position of the shield tunneling machine 1 so that it aligns with the planned linearity, and a corrected linearity selection unit 74 that selects one of a number of corrected linearities based on the deviation amount.

[0030] The planned linear shape stored in the planned linear shape storage unit 70 is linear shape data of the planned trajectory of the shield machine 1 designed based on the construction plan.

[0031] The excavation position memory unit 71 acquires and stores data from the survey instrument 4 mounted on the shield machine 1.

[0032] Excavation position data such as coordinates indicating the excavation position automatically surveyed from the surveying instrument 4 is transmitted to and stored in the excavation position storage unit 71. Surveying by the surveying instrument 4 is performed multiple times for each ring of the segment.

[0033] The excavation position data may also include azimuth angle information at any point of the shield machine 1 (for example, at a plurality of predetermined points on the central axis).

[0034] The deviation amount calculation unit 72 acquires the planned alignment from the planned alignment storage unit 70 and also acquires the excavation position from the excavation position storage unit 71.

[0035] The deviation amount calculation unit 72 calculates the amount of deviation of the excavation position from the planned alignment based on the acquired planned alignment and excavation position.

[0036] The deviation is the difference between the current position of the shield machine and the planned alignment, and is calculated in both the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) with respect to the tunnel advancement direction (Z-axis direction).

[0037] The corrected line shape stored in the corrected line shape memory unit 73, as shown in Figure 3, indicates the relationship between the deviation amount and the corrected excavation distance, which is the excavation distance from the excavation position to the target position on the planned line shape where the deviation amount is zero, and is a curve in which the deviation amount increases monotonically with respect to the corrected excavation distance, and multiple corrected excavation distances are set in order of increasing corrected excavation distance for the same deviation amount except for the target position.

[0038] The corrected alignment is shown with the deviation amount on the vertical axis and the corrected excavation distance on the horizontal axis. For the corrected alignment, the corrected excavation distance corresponds to the tunnel advance direction (Z-axis direction), and the deviation amount corresponds to the horizontal direction (X-axis direction) or vertical direction (Y-axis direction). In other words, there are corrected alignments set that show the relationship between the corrected excavation distance in the tunnel advance direction (Z-axis direction) and the deviation amount in the horizontal direction (X-axis direction), and those that show the relationship between the corrected excavation distance in the tunnel advance direction (Z-axis direction) and the deviation amount in the vertical direction (Y-axis direction). Both of these are the same and are shown in Figure 3.

[0039] In this embodiment, the correction line shape is a curve in which the ratio of the corrected excavation distance to the deviation amount increases as the line shape approaches the target position, and a part of a clothoid curve is adopted. Five correction line shapes are set, from correction line shape A, which has the largest corrected excavation distance to the deviation amount, to correction line shape E, which has the smallest corrected excavation distance to the deviation amount.

[0040] A clothoid curve is a curve that is drawn when the curvature is changed at a constant rate, and at any point on the curve, the product of the curve length from the starting point and the radius of curvature at that point is constant. If L is the curve length from the starting point (m), R is the radius of curvature (m), and P is the clothoid parameter (m), L×R=P 2 It is.

[0041] For example, the modified linear A is P 2 = 160, and the modified linear B is P 2 = 130, and the modified linear C is P 2 = 100, and the modified linear D is P 2 = 70, and the modified linear E is P 2 =40 clothoid curve.

[0042] When a clothoid curve is drawn on the ZX plane, which is the tunnel travel direction (Z-axis direction) and the horizontal direction (X-axis direction), Modified digging distance Z≒L×[1-L 2 / (2!×5×2 2 ×R 2 )+L 4 / (4!×9×2 4 ×R 4 )-L 6 / (6!×13×2 6 ×R 6 )] Deviation amount X ≒ L 2 / (6×R)×{1-L 2 / [(3!×7×2 2 ) / 3]×R 2 +L 4 / [(5!×11×2 4 ) / 3] ×R4 ]-L 6 / (7!×15×2 6 ) / 3×R 6 ]} It becomes.

[0043] R=P 2 Substituting / L into the above formula, Modified digging distance Z=L{1-L 2 / [2!×5×2 2 ×(P 4 / L 2 )]+L 4 / [4!×9×2 4 ×(P 8 / L 4 )]-L 6 / [6!×13×2 6 ×(P 8 / L 4 )]}...Formula 1 Deviation amount X ≒ L 2 / [6×(P 2 / L)]×{1-L 2 / [(3!×7×2 2 ) / 3]×(P 4 / L 2 )+L 4 / [(5!×11×2 4 ) / 3]×(P 8 / L 4 )]-L 6 / [(7!×15×2 6 ) / 3×(P 12 / L 6 )]}…Formula 2 It becomes.

[0044] In Equation 2, the deviation amount X and the corrected linear P 2 Calculate L by substituting L and P into Eq. 2 The corrected excavation distance Z can be calculated by substituting the above. In other words, by calculating the deviation amount, it is possible to know how far excavation is required to approach the planned alignment when excavating along a certain corrected alignment.

[0045] The same is true for the ZY plane, which is the tunnel travel direction (Z-axis direction) and the vertical direction (Y-axis direction). In addition, a correspondence table showing the relationship between the deviation amount and the corrected excavation distance for each corrected alignment may be created, and the corrected excavation distance may be obtained from an approximation of the deviation amount.

[0046] In order to correct the excavation direction, it is necessary to correct the angle of the shield machine 1 (for example, the angle in the face direction of the face plate of the rotating cutter 2) in both the horizontal and vertical directions. Since the corrected alignment is a curve where the deviation amount is zero at the target position, the correction angle of the shield tunneling machine 1 is determined for each corrected alignment according to the deviation amount.

[0047] A method for determining the correction angle will be described with reference to FIG. Using a certain correction alignment, a correction angle is calculated from the current excavation position n1 of the shield machine 1 to a specified excavation position n2 determined by surveying, which is the next pitch.

[0048] When the horizontal (X-axis) deviation amount at excavation position n1 is n1x [mm], the corrected excavation distance in the corrected alignment is n1z [m].

[0049] The excavation distance from excavation position n1 to excavation position n2 is determined in advance and known (for example, α [m]), so the corrected excavation distance n1z-α at that advanced position becomes the corrected excavation distance n2z at excavation position n2. The deviation amount n2x corresponding to the corrected excavation distance n2z of the excavation position n2 in the corrected alignment can be obtained.

[0050] The deviation amount n2x in the horizontal direction (X-axis direction) at this excavation position n2 is the target horizontal deviation amount, which is the deviation amount in the horizontal direction (X-axis direction) targeted for the next excavation.

[0051] The difference between the deviation amount n1x at the excavation position n1 and the target horizontal deviation amount (deviation amount n2x at the excavation position n2) is the deviation amount to be corrected with the current excavation distance α, so the correction angle is calculated based on this relationship. Correction angle=tan -1 ([n1x-n2x] / α) It is calculated based on the formula:

[0052] Similarly, the deviation amount n1y at the excavation position n1 in the vertical direction (Y-axis direction), the target vertical deviation amount (deviation amount n2y at the excavation position n2), and the correction angle can also be obtained. All corrective alignments can be found in a similar manner.

[0053] FIG. 5 shows the relationship between the deviation amount and the correction angle for each of the corrected linear shapes A to E. The correction angle relative to the deviation amount decreases in the order of the corrected linearity A to the corrected linearity E.

[0054] Then, a predetermined correction alignment is selected, and excavation is performed to excavation position n2 based on the correction angles in the horizontal direction (X-axis direction) and vertical direction (Y-axis direction) and the excavation distance (α) from excavation position n1 to excavation position n2.

[0055] When excavation has been completed up to excavation position n2, the excavation position data from the surveying instrument 4 is stored in the excavation position storage unit 71, and the deviation amount calculation unit 72 calculates the deviation amount.

[0056] Similarly, based on the calculated deviation amount, a correction angle is set up to excavation position n3 (not shown) for excavating the next α(m).

[0057] The correction line shape used for setting the correction angle is selected from a plurality of correction line shapes stored in the correction line shape storage unit 73 by the correction line shape selection unit 74 .

[0058] The selection of the corrected line shapes for the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) by the corrected line shape selection unit 74 is performed as follows. If the deviation amount calculated by the deviation amount calculation unit 72 is within a predetermined range (for example, less than ±5 mm in both the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction)), it is assumed that excavation is proceeding according to the planned linear alignment without any deviation, and no correction is made.

[0059] If the deviation amount calculated by the deviation amount calculation unit 72 exceeds a predetermined range (for example, 5 mm or more in either the horizontal direction (X-axis direction) or the vertical direction (Y-axis direction)), it is determined that there is a deviation from the planned alignment and correction is performed.

[0060] If the deviation amount calculated by the deviation amount calculation unit 72 is within a predetermined range from the target deviation amount when excavating along the previously used corrected alignment, the corrected alignment selection unit 74 selects the previously used corrected alignment.

[0061] If the deviation amount calculated by the deviation amount calculation unit 72 is smaller than the target deviation amount when excavating along the previously used corrected linear alignment by a predetermined value or more, the corrected linear alignment selection unit 74 selects a corrected linear alignment having a larger corrected excavation distance for the same deviation amount than the previously used corrected linear alignment.

[0062] If the deviation amount calculated by the deviation amount calculation unit 72 is greater than a predetermined value or more than the target deviation amount when excavating along the previously used corrected linear alignment, the corrected linear alignment selection unit 74 selects a corrected linear alignment having a smaller corrected excavation distance for the same deviation amount than the previously used corrected linear alignment.

[0063] A specific example of the selection of the corrected line shape in the vertical direction (Y-axis direction) by the corrected line shape selection unit 74 will be described with reference to FIG.

[0064] Suppose that the shield machine 1 is caused to excavate along the corrected alignment C a predetermined distance (e.g., 50 cm) from excavation position n1, where the deviation in the vertical direction (Y-axis direction) is +30 mm, to position n2, where the target vertical deviation amount is.

[0065] Correction alignment C is a correction alignment to gradually reduce the deviation amount of +30 mm to zero over a corrected excavation distance of 11.8 m.

[0066] The deviation calculation unit 72 calculates the deviation when 50 cm is excavated along the corrected alignment C.

[0067] If the deviation amount calculated by the deviation amount calculation unit 72 is within a predetermined range (a) from the target deviation amount at point n2 when excavating 50 cm along the corrected alignment C, the corrected alignment C used last time is continued to be selected, and the correction angle for the next excavation is set based on the corrected alignment C.

[0068] If the deviation amount calculated by deviation amount calculation unit 72 is smaller than the target deviation amount at point n2 when excavating 50 cm along corrected alignment C and falls outside a specified range (a) (b), the adjacent corrected alignment D is selected and the correction angle for the next excavation is set based on the corrected alignment D. In other words, because the shield machine 1 is approaching the planned alignment too abruptly, corrected alignment D that approaches the planned alignment more gradually is selected.

[0069] If the deviation amount calculated by deviation amount calculation unit 72 is larger than the target deviation amount at point n2 when excavating 50 cm along corrected alignment C and falls outside a specified range (a) (c), the adjacent corrected alignment B is selected and the correction angle for the next excavation is set based on the corrected alignment B. In other words, since the shield machine 1 has a tendency to move away from the planned alignment rather than approaching it, corrected alignment B, which approaches the planned alignment more rapidly, is selected.

[0070] The horizontal deviation is indicated as + if it is deviated to the right of the planned alignment in the direction of travel, and - if it is deviated to the left, while the vertical deviation is indicated as + if it is deviated above the planned alignment in the direction of travel, and - if it is deviated below the planned alignment.

[0071] The correction angle is determined based on the deviation amount in the selected correction alignment and from the relationship between the deviation amount and the correction angle (Figure 4).

[0072] The calculation of the deviation amount by the deviation amount calculation unit 72 and the selection of the corrected alignment by the corrected alignment selection unit 74 are performed multiple times while one ring of the segment is excavated. For example, if the segment width of one ring is 1 m and the survey by the surveying instrument 4 is performed every 50 cm, the selection of the corrected alignment is performed twice while one ring is excavated, and the alignment is corrected a maximum of two times.

[0073] In this embodiment, the shield jack control system 8 can automatically control the shield jack 5 based on the horizontal and vertical correction angles determined by the planned excavation line shape determination system 7.

[0074] As shown in Figure 6, the shield jack control system 8 includes a correction angle memory unit 80 that stores the horizontal and vertical correction angles determined by the planned excavation linearity determination system 7, a resultant force point calculation unit 81 that calculates the jack resultant force points of all shield jacks 5 from the horizontal and vertical correction angles stored in the correction angle memory unit 80, and a valve opening calculation unit 82 that calculates the opening of a valve 50 that adjusts the amount of oil supplied to the shield jack 5 based on the jack resultant force point calculated by the resultant force point calculation unit 81 and sends it to a valve control unit 51 that controls the opening of the valve.

[0075] The correction angle memory unit 80 stores data on the horizontal and vertical correction angles determined by the planned excavation line shape determination system 7 (including the correction angles and the next excavation distance).

[0076] The resultant force point calculation unit 81 first reads out the horizontal and vertical correction angles stored in the correction angle memory unit 80, and calculates the force point coordinates in the horizontal direction (X-axis direction) and the vertical direction (Y-axis direction) when the center of any cross section of the shield tunneling machine 1 is set as the center point and the upward vertical direction is set as 0°.

[0077] The horizontal force point coordinate is obtained by dividing the horizontal correction angle by the maximum correction angle value, and the vertical force point coordinate is obtained by dividing the vertical correction angle by the maximum correction angle value.

[0078] The maximum correction angle is the maximum limit value that can be set as the correction angle. For example, the deviation amount is set to 60 mm based on the construction results, and the correction line A is used to calculate and set as 0.730, which is a correction line that corrects the assumed correction curve at a steep angle.

[0079] Next, based on the horizontal and vertical force point coordinates, the distance from the center point to the jack resultant force point (resultant force point distance) and the angle of the line connecting the center point and the jack resultant force point (resultant force point angle) are calculated.

[0080] An example of calculation is shown in Figure 7. In this example, the resultant force point calculation unit 81 calculates the force point coordinates from the horizontal correction angle calculated and stored as -0.214 for correction along correction alignment C when the horizontal deviation amount is -20 mm, and the vertical correction angle calculated and stored as -0.343 for correction along correction alignment B when the vertical deviation amount is -30 mm.

[0081] Since the maximum correction angle is 0.730, the horizontal force point coordinate is calculated as -0.214 / 0.730=-0.2932. Since the maximum correction angle is 0.730, the vertical force point coordinate is calculated as -0.343 / 0.730=-0.4699.

[0082] The distance from the center point to the jack resultant point (resultant point distance) is: √(0.2932 2 +0.4699 2 )=0.5539. In addition, the angle of the line connecting the center point and the jack resultant point (resultant point angle) is tan -1 Using the function, vertically upwards is 0° and expressed clockwise, it becomes 211.963°.

[0083] When the opening of the valve 50 is increased, the jack thrust also increases. The valve opening calculation unit 82 calculates the opening of the valve 50 so that the thrust of the shield jack 5 located closer to the direction from the center point to the jack combination point (the shield jack 5 within the range covered by the jack combination point) is increased and the thrust of the shield jack 5 located in the opposite direction is decreased.

[0084] In addition, the opening degree of each valve 50 corresponding to the shield jack 5 is calculated so that the opening degree of the valve 50 corresponding to that shield jack 5 becomes smaller in proportion to the difference in angle between the arrangement position of the shield jack 5 and the jack resultant force point.

[0085] In order to avoid an extreme one-sided pushing state, the difference in the opening degree of the valve 50 of the high thrust jack and the low thrust jack may be set as a threshold value and calculations may be made to adjust the difference within an allowable range.

[0086] Based on the maximum valve opening, which is the maximum opening set for the valve 50, and the minimum valve opening, which is the minimum, and the resultant force point distance, the amount of change in the valve opening when the position of the shield jack 5 changes by 1 degree from the resultant force point angle is calculated.

[0087] In the case of maximum valve opening: 100, minimum valve opening: 50, and resultant point distance: 0.5539, the change in valve opening when the angle of the line connecting the placed shield jack 5 and the center point (jack angle) changes by 1 degree from the resultant point angle is: (100-50)×0.5539 / 180=0.1539.

[0088] The angle difference between the jack angle and the resultant force angle is calculated to calculate the valve opening degree of each shield jack 5. The difference between the jack angle and the resultant force angle is set to a maximum of 180°.

[0089] The resultant force angle is 180° or less, (1) When the jack angle is greater than the resultant force angle +180°, Angle difference = resultant force angle + 360° - jack angle. (2) In cases other than (1), Angle difference = jack angle - resultant force angle.

[0090] The resultant force angle is greater than 180°, (1) When the jack angle is greater than the resultant force angle -180°, Angle difference = resultant force angle - jack angle. (2) In cases other than (1), Angle difference = (jack angle + 360°) - resultant force angle.

[0091] Furthermore, the valve opening degree of each shield jack 5 is calculated based on the calculated angle difference. The valve opening calculated by the valve opening calculation unit 82 is sent to the valve control unit 51, and the valve control unit 51 adjusts the opening of the valve 50 of each shield jack 5 according to the calculated valve opening.

[0092] In the example shown in FIG. 7, twelve shield jacks 5 (No. 1 to No. 12) are arranged at a pitch of 30° clockwise. Specifically, with 0° vertically upward, No. 1 is located 15° clockwise, and then No. 12 is arranged at intervals of 30° clockwise.

[0093] When calculating the valve opening of No. 1 shield jack 5, the maximum valve opening is 100, the change in valve opening per degree of angle change is 0.1539, and the angle difference is 163.037, so The answer is 100-(0.1539×163.037)=74.9.

[0094] FIG. 8 shows the jack angle, angle difference, valve opening difference, and valve opening of each shield jack 5 calculated in a similar manner.

[0095] FIG. 9 shows the process of determining the planned excavation line shape of the shield machine 1.

[0096] When the shield machine 1 starts excavating and, in step 1, the surveying instrument 4 surveys the excavation position of the shield machine 1 (S1), in step 2 the excavation position data is stored in the excavation position memory unit 71 (S2).

[0097] Next, in step 3, the deviation amount calculation unit 72 calculates the deviation amount based on the excavation position read out from the excavation position storage unit 71 and the planned alignment read out from the planned alignment storage unit 70 (S3).

[0098] Next, in step 4, the corrected line shape selection unit 74 selects one of the multiple corrected line shapes stored in the corrected line shape storage unit 73 based on the deviation amount calculated by the deviation amount calculation unit 72 (S4).

[0099] In step 5, the horizontal and vertical correction angles determined in accordance with the corrected line shape selected by the corrected line shape selection unit 74 are stored in the correction angle storage unit 80 of the shield jack control system 8 (S5).

[0100] Furthermore, in step 6, the resultant force point calculation unit 81 calculates the jack resultant force point based on the correction angle read out from the correction angle storage unit 80 (S6).

[0101] Next, in step 7, the valve opening degree calculation unit 82 calculates the opening degree of the valve 50 from the jack resultant force point calculated by the resultant force point calculation unit 81 (S7).

[0102] In step 8, the opening of the valve 50 calculated by the valve opening calculation unit 82 is sent to the valve control unit 51 (S8), and the process ends.

[0103] When the excavation position of the tunnel boring machine deviates from the planned alignment, the system can correct it along a correction alignment selected from multiple correction alignments set in advance based on the deviation amount, so there is no variation due to differences in individual skills, experience, etc. In addition, the excavation position can be easily and reliably brought close to the planned alignment without performing troublesome trajectory calculations.

[0104] In addition, if the correction curve is a curve in which the ratio of the corrected excavation distance to the deviation amount increases as it approaches the target position, the angle of the corrected alignment relative to the planned alignment becomes gradually gentler as it approaches the target position, so that the excavation position can be gradually and stably moved closer to the planned alignment.

[0105] In addition, when the deviation amount exceeds a threshold value, if the deviation amount is greater than the target deviation amount when excavating along the previously selected corrected alignment, the correction alignment selection unit selects a correction alignment having a smaller corrected excavation distance for the same deviation amount than the previously selected corrected alignment, and if the deviation amount is the same as the target deviation amount when excavating along the previously selected corrected alignment, it selects the previously selected corrected alignment, and if the deviation amount is smaller than the target deviation amount when excavating along the previously selected corrected alignment, it selects a correction alignment having a larger corrected excavation distance for the same deviation amount than the previously selected corrected alignment.In this way, only when a trajectory correction of the tunnel boring machine is necessary, can the optimal correction be made reliably without deviating significantly from the planned alignment.

[0106] The shield jack control system can appropriately control each valve of the shield jack based on the resultant force point corresponding to the target correction angle, without variation due to differences in individual skill or experience.

[0107] [Second embodiment] 10 to 12 show a second embodiment of the present invention. Note that a description of the same parts as in the first embodiment will be omitted, and differences will be mainly described.

[0108] In the second embodiment, as shown in FIG. 10, the 12 shield jacks 5 are grouped into an upper block 5a consisting of two shield jacks 5 (No. 1, No. 12), a right block 5b consisting of four shield jacks 5 (No. 2 to No. 5), a lower block 5c consisting of two shield jacks 5 (No. 6, No. 7), and a left block 5d consisting of four shield jacks 5 (No. 8 to No. 11), and the shield jacks 5 are controlled for each block.

[0109] The upper block 5a, the right block 5b, the lower block 5c, and the left block 5d are each equipped with one block valve 50' (Fig. 1), meaning that valve control for four systems is possible. In addition, each block may have a set of multiple jacks, and the number of blocks may be four or more, and is not limited to this embodiment.

[0110] As shown in Figure 11, the shield jack control system 8 includes a correction angle memory unit 80 that stores the horizontal and vertical correction angles determined by the planned excavation linearity determination system 7, a resultant force point calculation unit 81 that calculates the jack resultant force points of all shield jacks 5 from the horizontal and vertical correction angles stored in the correction angle memory unit 80, and an individual jack valve opening calculation unit 82' that calculates the opening of each valve of the shield jack 5 when the shield jacks 5 are individually controlled by valves based on the jack resultant force points calculated by the resultant force point calculation unit 81, and a block valve opening calculation unit 83 that calculates the opening of the block valve 50' for each block.

[0111] The individual jack valve opening calculation unit 82' calculates the opening of each valve of the shield jack 5 on the assumption that the shield jack 5 is individually controlled by a valve, which is actually a block valve provided for each block, and the calculation method is the same as that of the valve opening calculation unit 82 of the first embodiment.

[0112] The block valve opening calculation unit 83 calculates the valve opening of the block valve 50' of each block as follows.

[0113] The valve opening of the 12 shield jacks 5 calculated by the individual jack valve opening calculation unit 82' is used to calculate the block total valve opening, which is the sum of the valve openings of the shield jacks 5 that make up the upper block 5a, the right block 5b, the lower block 5c, and the left block 5d.

[0114] To explain this more specifically based on the example shown in FIG. 8 of the first embodiment, the block total valve opening degree of the two shield jacks 5 (No. 1, No. 12) of the upper block 5a is 74.9+79.5=154.4.

[0115] The total valve opening degree of the four shield jacks 5 (No. 2 to No. 5) in the right block 5b is 74.3 + 78.9 + 83.5 + 88.2 = 324.9.

[0116] The total valve opening of the two shield jacks 5 (No. 6, No. 7) in the lower block 5c is 92.8 + 97.4 = 190.2.

[0117] The total valve opening of the four shield jacks 5 (No. 8 to No. 11) in the left block 5d is 98.0 + 93.4 + 88.8 + 84.1 = 364.3.

[0118] Next, the coordinates of the individual block jack resultant force point of each block are calculated from the block total valve opening degree and the block angle of each block.

[0119] The X coordinate is calculated by the sum of sin(block angle) × total block valve opening / maximum valve opening, The Y coordinate is calculated by the sum of cos(block angle) x block total valve opening / maximum valve opening.

[0120] Here, the block angle is the angle at the center position of each block, and is the angle measured clockwise with directly above being 0°. Specifically, the block angle of upper block 5a is 0°, since it is the angle between No. 1 and No. 12. Similarly, the block angle of right block 5b is 90°, the block angle of lower block 5c is 180°, and the block angle of left block 5d is 270°.

[0121] As a specific example of the example shown in FIG. 10, the X coordinate of the individual block jack resultant force point of the right block 5b is as follows: sin90°×324.9 / (100×4)=0.8123.

[0122] In addition, the Y coordinate of the individual block jack resultant force point of the upper block 5a is cos0°×154.4 / (100×2)=0.7720.

[0123] The X and Y coordinates of the individual block jack resultant force points of each of the other blocks are calculated in the same manner. The sum of the X-coordinates and the Y-coordinates of the calculated individual block jack combined force points of the upper block 5a, the right block 5b, the lower block 5c, and the left block 5d become the X-coordinates and the Y-coordinates of the overall block jack combined force point, which is the jack combined force point of all blocks.

[0124] FIG. 12 shows the X and Y coordinates of the individual block jack resultant force points of each block, and the X and Y coordinates of the overall block jack resultant force point of all blocks.

[0125] Next, from the X and Y coordinates of the overall block jack resultant point, the overall block jack resultant point angle, which is the angle of the line connecting the center point and the overall block jack resultant point, and the overall block jack resultant point distance, which is the distance from the center point to the overall block jack resultant point, are calculated.

[0126] Furthermore, based on the maximum valve opening and minimum valve opening set for the block valve 50' and the overall block jack resultant force point distance, a block valve opening change amount is calculated, which is the amount of change in the block valve opening when the positions of the upper block 5a, right block 5b, lower block 5c, and left block 5d change by 1 degree from the overall block jack resultant force point angle.

[0127] Next, a block angle difference is calculated, which is the difference between the angle (block angle) of a straight line connecting the center point and the positions where the upper block 5a, right block 5b, lower block 5c, and left block 5d are located, and the overall block jack resultant force point angle.Based on the block valve opening change and the block angle difference, the opening of the block valve 50' of the upper block 5a, right block 5b, lower block 5c, and left block 5d is calculated.

[0128] An individual jack valve opening calculation unit is provided to virtually calculate the valve opening of each jack individually, and the block valve opening calculation unit calculates the block valve opening based on that, making it possible to provide a jack control system that is highly versatile and can easily accommodate shield machines of either the individual jack valve type or the block valve type.In other words, not providing the block valve opening calculation unit 83 makes it possible to accommodate the individual jack valve type, and providing the block valve opening calculation unit 83 makes it possible to accommodate the block valve type.

[0129] [Third embodiment] 13 and 14 show a third embodiment of the present invention. Note that a description of the same parts as in the first and second embodiments will be omitted, and the following mainly describes the different parts.

[0130] In the third embodiment, as shown in FIG. 13, 16 shield jacks 5 are arranged at equal angles, and the shield jacks 5 are controlled in blocks of four.

[0131] Specifically, the upper block 5a consists of four shield jacks 5 (No. 1, No. 2, No. 15, No. 16), the right block 5b consists of four shield jacks 5 (No. 2 to No. 6), the lower block 5c consists of four shield jacks 5 (No. 7 to No. 10), and the left block 5d consists of four shield jacks 5 (No. 11 to No. 14), and the shield jacks 5 are controlled by each block.

[0132] In the same manner as in the second embodiment, the valve opening degree of the valve 50 in each block is calculated and controlled.

[0133] In the third embodiment, as shown in FIG. 14, a display 60 will be described which displays the control state such as the calculation result and also allows manual input of a control value.

[0134] The display 60 is a touch panel and is connected to an input / output control unit (not shown) that the control device 6 has.

[0135] The display 60 has a right display section 61 which indicates the valve opening of the valves 50 in each block, and is color-coded according to the color and the jack length.

[0136] The color-coded display divides the degree of jack opening into stages (for example, from 1, which is the lowest opening, to 10, which is the highest opening) and displays the jack in gradually darker colors (for example, from white to deep red).

[0137] The overall direction based on the valve opening and jack length is displayed in three dimensions. This allows the orientation of the shield machine 1 to be intuitively understood.

[0138] The display 60 displays the arrangement of the shield jacks 5 in a left display section 62 as a planar rear view as viewed from the rear.

[0139] The rear display shows the calculated valve opening angle 62a using numbers for the valves 50 of each block, a resultant force point display 62b which shows the calculated jack resultant force point combining all the jacks, and a machine direction display 62c using an arrow showing the calculated direction in which the shield tunneling machine 1 is facing.

[0140] The resultant force point indication 62b is displayed as a colored dot (e.g., a red dot), and the machine direction indication 62c is displayed as an arrow (e.g., a red arrow) colored the same color as the resultant force point indication 62b.

[0141] Furthermore, a maximum range display 62d of the jack resultant force point that can be calculated by the shield jack control system 8 is displayed by a colored (for example, red) circle with a thick line.

[0142] The maximum range display 62d indicates the range of automatic control by the shield jack control system 8. That is, in the automatic control by the shield jack control system 8, the jack resultant force point is always set inside the maximum range display 62d.

[0143] The maximum range display 62d is set, for example, by multiplying the resultant force point calculated based on the maximum correction angle value by a safety factor. If it is desired to set the jack resultant force point outside the maximum range display 62d, it is necessary to set it manually.

[0144] At the top, right, bottom and left of the rear display, jack resultant force point moving buttons 62e are displayed, which enable the jack resultant force point to be moved up, down, left and right and set in the manual mode.

[0145] The manual mode can be switched from the automatic mode by operating the manual operation button 62f. In the manual mode, the valve 50 is controlled by a manual operation control unit (not shown) connected to the valve control unit 51.

[0146] The jack force point moving button 62e is activated by touching the manual operation button 62f displayed at the bottom right, i.e., in manual mode. By touching each of the jack force point moving buttons 62e, the jack force point can be moved up, down, left, or right and set.

[0147] The jack resultant force point set in the manual mode is displayed as a manual resultant force point display 62h.

[0148] Based on the jack resultant force point set in the manual mode, the direction in which the shield tunneling machine 1 faces in the manual mode is calculated, and a manual machine direction indication 62i is displayed using an arrow.

[0149] The manual resultant force point display 62h is displayed as a dot (e.g., a blue dot) colored in a different color from the resultant force point display 62b, and the manual machine direction display 62i is displayed as an arrow (e.g., a blue arrow) colored in the same color as the manual resultant force point display 62h.

[0150] In addition, the valve opening is calculated based on the jack resultant force point set in the manual mode and is displayed on the valve opening display 62a.

[0151] Switching from the manual mode to the automatic mode can be performed by touching the automatic adjustment button 62g to return to automatic adjustment by the shield jack control system 8.

[0152] In the automatic mode, the jack force point is always set inside the maximum range display 62d, but in the manual mode, the jack force point can be set regardless of the maximum range display 62d. That is, the jack force point can be set either inside or outside the maximum range display 62d.

[0153] As a result, when it is necessary to set the jack resultant force point beyond the maximum range display 62d in the automatic mode, it becomes necessary to switch to the manual mode, and excavation can be carried out more carefully and safely.

[0154] Also, for example, if the automatic mode is set so that one-sided pushing is not possible, and the manual mode is set so that one-sided pushing is possible, the mode can be switched as needed for one-sided pushing, allowing excavation while checking safety.

[0155] In this embodiment, both the resultant force point display 62b and the machine direction display 62c in the automatic mode and the manual resultant force point display 62h and the manual machine direction display 62i in the manual mode are displayed simultaneously, but it is also possible to switch between modes to display only one of the modes.

[0156] [Other Modifications] The present invention is not limited to the above-mentioned embodiment, and may also include the following, for example.

[0157] In this embodiment, the tunnel boring machine is a shield machine, but is not limited to this and may be a tunnel boring machine such as a TBM (tunnel boring machine) equipped with a driving jack.

[0158] In this embodiment, the corrected linear shape is a clothoid curve, but it may be any other curve, such as a curve showing an exponential function, as long as the deviation amount with respect to the corrected excavation distance increases monotonically.

[0159] In this embodiment, twelve shield jacks are used in the second embodiment, and sixteen shield jacks are used in the third embodiment, but the number can be increased or decreased.

[0160] In this embodiment, automatic surveying using the surveying instrument 4 is performed multiple times for each ring excavation and the planned excavation line is determined based on the data, but this is not limited to this, and it is also possible to perform a single survey for each ring excavation and determine the planned excavation line based on the data.

[0161] In this embodiment, automatic surveying is performed using a surveying instrument attached to the shield machine, but it may also be conventional manual surveying in which a surveying instrument is installed inside the tunnel.

[0162] In the second and third embodiments, the shield jack is divided into four blocks, but it may be divided into more blocks.

[0163] Each technical matter in any of the embodiments including the modified examples may be applied to other embodiments to serve as examples.

[0164] 1. Shield tunneling machine 2 Rotation Cutter 3. Chamber 4 Surveying equipment 5 Shield Jack 5a Upper block 5b Right Block 5c Lower Block 5d Left block 50 Valve 50' Block Valve 51 Valve control section 6. Control device 60 Display 61 Right side display 62 Left side display 62a Valve opening display 62b Resultant point display 62c Machine Orientation Indicator 62d Maximum range display 62e Jack force point movement button 62f Manual operation button 62g Auto Adjustment Button 62h Manual resultant point display 62i Manual Machine Orientation Display 7. System for determining planned tunnel alignment 70 Plan Linear Memory Section 71 Excavation position memory section 72 Deviation amount calculation section 73 Modified linear memory 74 Modified Linear Selection Section 8. Shield Jack Control System 80 Correction angle storage section 81 Resultant force point calculation section 82 Valve opening calculation unit 82' Individual jack valve opening calculation section 83 Block valve opening calculation unit

Claims

1. A system for determining a planned excavation alignment used when a tunnel boring machine excavates, for determining a correction alignment for correcting a deviation of an excavation position from a planned alignment, comprising: a planned alignment storage unit that stores the planned alignment along which the tunnel boring machine is to excavate; A deviation amount calculation unit that calculates a deviation amount of the excavation position with respect to the planned alignment; a correction line shape storage unit that stores a correction line shape for correcting the excavation position of the tunnel boring machine so as to be aligned with the planned line shape; The corrected line shape stored in the corrected line shape storage unit indicates the relationship between the deviation amount and a corrected excavation distance, which is the excavation distance from the excavation position to a target position on the planned line shape where the deviation amount is zero, and is a curve in which the deviation amount increases monotonically with respect to the corrected excavation distance, The correction alignment is set in a plurality of positions in order of increasing the correction excavation distance for the same deviation amount except for the target position, a correction line shape selection unit that selects one of the plurality of correction line shapes based on the deviation amount; A system for determining a planned excavation line shape for a tunnel boring machine, comprising:

2. 2. The system for determining a planned excavation alignment for a tunnel boring machine according to claim 1, wherein the corrected alignment is a curve in which the ratio of the corrected excavation distance to the deviation amount increases as the corrected alignment approaches the target position.

3. When the deviation amount calculated by the deviation amount calculation unit exceeds a threshold value, If the deviation amount is greater than the target deviation amount when excavating along the previously selected corrected alignment, the corrected alignment selection unit selects a corrected alignment having a smaller corrected excavation distance for the same deviation amount than the previously selected corrected alignment, If the deviation amount is the same as the target deviation amount when excavating along the previously selected corrected alignment, the corrected alignment selection unit selects the previously selected corrected alignment, If the deviation amount is smaller than the target deviation amount when excavating along the previously selected corrected alignment, the corrected alignment selection unit selects a corrected alignment having a larger corrected excavation distance for the same deviation amount than the previously selected corrected alignment.

3. A system for determining a planned excavation line shape for a tunnel boring machine according to claim 1 or 2.

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