JP6901611B2 - Bit vibration tester - Google Patents

Description

The present invention relates to a bit vibration test device, and more particularly to a bit vibration test device used for a method of determining a face ground in a shield excavator in which an acceleration sensor is attached to a cutter head.

In recent years, for example, in urban areas, it has been desired to construct shield tunnels over a long distance because of problems with shaft sites and congestion with underground buried objects. When constructing a shield tunnel over a long distance, the soil quality of the ground on the face surface often changes with the excavation by the shield excavator, and when excavating the boundary part of the ground of different laminated soil. May have different soils appearing at the same time on the same face to be cut. In addition, in the closed type shield excavator represented by muddy soil pressure type and muddy water type, the ground on the face surface cannot be confirmed directly, so the properties of the excavated soil, the cutter torque of the cutter head, the excavation speed of the shield excavator, etc. The ground is estimated and excavation is carried out. For this reason, in shield tunnels with large cross sections where stratum boundaries are likely to appear on the face surface and shield tunnels with complicated ground changes, it is necessary to manage the excavation of shield excavators so that they match the ground conditions. Is getting harder.

On the other hand, the inventors of the present application attach an acceleration sensor in the vicinity of the cutter bit provided on the cutter head, and obtain the response acceleration (vibration data) generated when cutting the ground on the face surface of the cutter head. We are proposing a face soil distribution discrimination system and a judgment method that can judge the ground condition of the face surface by measuring with an acceleration sensor while rotating (see, for example, Patent Document 1 and Patent Document 2). ..

Japanese Unexamined Patent Publication No. 10-19853 Japanese Unexamined Patent Publication No. 2016-3249

According to the discrimination system and the determination method described in Patent Document 1 and Patent Document 2, it is possible to excavate the shield excavator while determining the soil quality of the ground to be excavated on the face surface, and at the same time, the determined ground From the history of soil quality, it is possible to predict the soil quality of the ground in front of the face surface, but on the other hand, the soil quality of the ground is, for example, boring performed in advance at the construction site before excavation by a shield excavator. The actual situation is that the judgment is made by comparing the result of the ground investigation by the above with the change of the response acceleration measured by the acceleration sensor when cutting the face surface, and the cutter at the time of excavation of the shield excavator. Since the judgment was not made by reflecting parameters such as the rotation speed of the head, the digging speed of the shield excavator, and the difference in the cutter bit, these parameters are reflected to more accurately judge the soil quality of the ground on the face surface. The development of technology that enables this is desired.

In the present invention, the rotation speed of the cutter head, the excavation speed of the shield excavator, the difference in the cutter bit, etc. at the time of excavation of the shield excavator are reflected as parameters, and the soil quality of the ground on the face surface is determined more accurately. It is an object of the present invention to provide a bit vibration test apparatus used for a method for determining a face ground in a shield excavator capable of performing the same.

The present invention is a method for determining the face ground in a shield excavator including an acceleration sensor attached to a cutter head and a computer connected to the acceleration sensor, which is provided with a face soil distribution discrimination system. Using the excavation surplus soil collected when constructing the shaft or the excavation surplus soil collected from the excavation site around the construction site, multiple simulated soil layers are formed, and a cutter bit is embedded in each simulated soil layer formed. The vibration data when moving is collected by an accelerometer, and the collected vibration data is stored in advance in the computer as cutting vibration data corresponding to each simulated soil layer, and the shield excavator is installed at the construction site. When cutting the ground with the cutter head, the soil quality of the faceted ground being cut is determined by comparing the vibration data obtained by the accelerometer with the cutting vibration data of each simulated soil layer stored in advance. A bit vibration test device used when collecting cutting vibration data corresponding to each simulated soil layer in a method for determining face ground in a shield excavator, and is an upper surface that houses the simulated soil layer in a compacted state. The soil layer accommodating tank having an opening surface and the cutter bit are detachably supported and fixed, and the bit fixing jig and the bit fixing jig to which the acceleration sensor is attached are attached to the inside of the soil layer accommodating tank. It is configured to include a lateral moving device for moving the bit fixing jig in the lateral direction along the opening surface and a depth moving device for moving the bit fixing jig in the depth direction inside the soil layer accommodating tank. Bit vibration that collects vibration data by the accelerometer while embedding the cutter bit in the simulated soil layer housed in the soil layer storage tank and moving it in the lateral direction and the depth direction along the opening surface. By providing a test device, the above object has been achieved.

Further, in the bit vibration test device of the present invention, the lateral moving device can reciprocate the bit fixing jig in the lateral direction along the opening surface inside the soil layer accommodating tank. Is preferable.

Further, in the bit vibration test device of the present invention, the lateral moving device can move the bit fixing jig in a linear direction along the opening surface inside the soil layer accommodating tank. Is preferable.

Furthermore, in the bit vibration test apparatus of the present invention, it is preferable that the cutter bit can move in the lateral direction and the depth direction in a variable speed.

Further, in the bit vibration test apparatus of the present invention, it is preferable that the bit fixing jig supports and fixes the cutter bit so as to be removable and replaceable.

Further, in the bit vibration test apparatus of the present invention, the cutter bit that is detachably supported and fixed to the bit fixing jig is a reinforced leading bit that is advantageous for the ground made of gravel soil, and silty soil, clay, or. It preferably contains a leading bit used for ground with sandy silt.

According to the bit vibration test device used for the method of determining the face ground in the shield excavator of the present invention, the rotation speed of the cutter head, the excavation speed of the shield excavator, the difference in the cutter bit, etc. at the time of excavation of the shield excavator are parameters. It is possible to judge the soil quality of the ground on the face surface more accurately.

It is explanatory drawing of the face soil distribution discrimination system used for the judgment method of the face ground in a shield excavator. It is a perspective view of the bit vibration test apparatus which concerns on one preferred embodiment of this invention. It is a front view of the bit vibration test apparatus. It is a top view of the bit vibration test apparatus. It is a side view of the bit vibration test apparatus. (A) is a front view and a side view illustrating the enhanced leading bit, and (b) is a front view and a side view illustrating the type leading bit. It is a chart exemplifying the acceleration change due to the difference in soil quality. It is a chart which shows the relationship between the horizontal movement speed and the response acceleration in a clay layer. It is a chart which shows the relationship between the horizontal movement speed and the response acceleration in a sand layer. It is a chart which shows the relationship between the horizontal movement speed and the response acceleration in a gravel layer. It is a chart which shows the Fourier spectrum in the Z direction in a clay layer. It is a chart which shows the Fourier spectrum in the Z direction in a sand layer.

The bit vibration test apparatus according to a preferred embodiment of the present invention is used as an apparatus for collecting cutting vibration data corresponding to each simulated soil layer in a method for determining a face ground in a shield excavator described later. The method for determining the face ground in the shield excavator is as a method for accurately determining the soil quality of the face surface of the shield excavator 11 during excavation by using the face soil distribution determination system 10 shown in FIG. It was adopted.

Here, the face soil distribution determination system 10 shown in FIG. 1 is a closed-type shield excavator, for example, in the construction of constructing a shield tunnel by a mud pressure type shield excavator 11, the ground 12a of the face surface being cut. This is a system that enables the status of 12b and 12c to be grasped in real time. That is, for example, in urban areas, the shield tunnel is lengthened not only by a large-diameter shield excavator but also by a medium- and small-diameter shield excavator because of problems with the shaft site and congestion with underground buried objects. When constructing a shield tunnel over a long distance, the soil quality of the grounds 12a, 12b, and 12c of the face surface 12 often changes with the excavation by the shield excavator 11. Further, when excavating the boundary portion of the laminated grounds 12a, 12b, 12c of different soils, the grounds 12a, 12b, 12c of different soils may appear at the same time on the same face surface 12 to be cut. In the face soil distribution discrimination system 10 shown in FIG. 1, an acceleration sensor 14 is attached in the vicinity of the cutter bit 16 provided on the cutter head 13, and the grounds 12a, 12b, and 12c of the face surface 12 are cut by the cutter bit 16. The response acceleration generated during this operation is measured by the acceleration sensor 14 while rotating the cutter head 13 as vibration data, and the conditions of the grounds 12a, 12b, and 12c of the face surface 12 can be determined.

In the present embodiment, the method for determining the face ground is the rotation of the cutter head 13 during excavation of the shield excavator 11 when determining the soil quality of the grounds 12a, 12b, 12c of the face surface 12 by the above-mentioned determination system 10. By reflecting parameters such as the speed, the excavation speed of the shield excavator 11, and the difference in the cutter bit 16, the soil quality of the grounds 12a, 12b, and 12c of the face surface 12 can be determined more accurately.

The bit vibration test device 50 of the present embodiment is a shield excavator including a face soil distribution discrimination system 10 including an acceleration sensor 14 attached to the cutter head 13 and a computer 20 connected to the acceleration sensor 14. In the method for determining the face ground in No. 11, a plurality of simulated soil layers 40 are formed by using the excavated residual soil collected when constructing the shaft 30 at the construction site or the excavated residual soil collected from the excavation site around the construction site. Vibration data, which is the response acceleration when the cutter bit 16 is embedded and moved in each of the formed simulated soil layers 40, is collected by the acceleration sensor 14, and the collected vibration data. Is stored in the computer 20 in advance as cutting vibration data corresponding to each simulated soil layer 40, and an acceleration sensor is used when cutting the ground 12a, 12b, 12c with the cutter head 12 of the shield excavator 11 at the construction site. A shield excavator that determines the soil quality of the ground 12a, 12b, 12c of the face being cut by comparing the vibration data obtained by 14 with the cutting vibration data of each simulated soil layer 40 stored in advance. In the method for determining the face ground in the above, it is a test device used when collecting cutting vibration data corresponding to each simulated soil layer 40, and it is possible to sequentially replace and accommodate the simulated soil layer 40 in a compacted state. The soil layer storage tank 51 having an opening surface 51a on the upper surface and the cutter bit 16 are detachably supported and fixed, and the bit fixing jig 52 and the bit fixing jig 52 to which the acceleration sensor 14 is attached are supported. A lateral movement device 53 that preferably reciprocates in the lateral direction X along the opening surface inside the soil layer storage tank 51, and a depth that moves the bit fixing jig 52 in the depth direction Z inside the soil layer storage tank 51. It is configured to include a longitudinal moving device 54. The cutter bit 16 is embedded in the simulated soil layer 40 housed in the soil layer storage tank 51, and the cutter bit 16 is moved by the acceleration sensor 14 in the lateral direction X and the depth direction Z along the opening surface 51a. Vibration data (response acceleration) is collected.

In the present embodiment, as shown in FIG. 1, the shield excavator 11 is, for example, a mud pressure type shield excavator known as a closed type shield excavator. The mud pressure type shield excavator 11 is provided with a partition wall 17 for forming a partition chamber 19 filled with mud pressure behind the cutter head 13 at the tip of the shield body 15, and is supported by the partition wall 17. The center shaft 13a of the cutter head 13 is provided. Further, inside the shield main body 15, a mud draining mechanism (not shown), a rotary drive motor (not shown), a shield jack (not shown), an erector (not shown), and the like are provided.

In the present embodiment, the computer 20 constituting the face soil distribution determination system 10 is a known computer that functions as a database server, and for example, a personal computer or the like can be used. The database server as the computer 20 includes a CPU, a ROM, a RAM, an I / F, a storage means, an input means, a display means, an output means, and the like. The CPU of the database server controls the overall operation of the database server while using the RAM as a work area according to the control program embedded in the ROM. Further, the CPU functions as a storage means, an input means, a display means, an output means, etc. by incorporating various computer programs in the ROM, and is also shielded by the vibration data storage unit 21 from the acceleration sensor 14. The vibration data, which is the response acceleration during construction of the excavator 11, is stored together with the rotation angle of the cutter head 13, and the vibration data stored in the vibration data storage unit 21 by the vibration data display unit 22 is stored in a circle. It can be displayed on the display 24 as the cutting vibration distribution 23 distributed in the circumferential direction, or the soil distribution of the ground 12a, 12b, 12c ahead of the face surface 12 in the excavation direction can be determined by the front soil distribution determination unit 32. It has become.

Further, in the present embodiment, the computer 20 is a known shield capable of centrally managing the measured values collected from various measuring instruments in the shield method and the surveyed values input as data via the input means. A digging management system is built in. The shield excavation management system is a function that supports on-site construction management by centrally managing the measured values collected from various measuring instruments in the shield method, for example, and organizing the information and providing it to engineers and workers. Or, a function to estimate the condition of the ground, the condition of excavated earth and sand, the condition of addition of the shield excavator, etc. based on the change over time and the result of statistical processing, or by inputting the measurement result, the seal excavator or segment It has a function to calculate the position and obtain the deviation from the baseline. As such a shield excavation management system, a "shield excavation management system" manufactured by Arithmetic Studio Co., Ltd. can be preferably used.

Further, in the present embodiment, the computer 20 is installed in the operation control room 31 provided on the ground, and the computer 20 installed in the operation control room 31 is, for example, via the accelerometer amplifiers 25a and 25b. , PCL control panel 26, sequencer panel 27, remote control panel 28, etc. are connected to various measuring instruments, an acceleration sensor 14 and an auxiliary acceleration sensor 18, which will be described later, via a known transmission system 29. ..

The acceleration sensor 14 and the auxiliary acceleration sensor 18 constituting the face soil distribution discrimination system 10 shown in FIG. 1 together with the computer 20 are various accelerations known as sensors for detecting the acceleration which is the time change rate (time derivative) of the velocity. A sensor can be used. Accelerometers are used to measure the value of acceleration itself and to detect when an external force is applied, using the laws of physics that the acceleration acting on an object is proportional to the applied external force. The accelerometer 14 and the auxiliary accelerometer 18 can detect tilt, vibration, movement, impact, drop, etc., in addition to scientific experiments that require highly accurate measurement, gravity measurement, seismic measurement, and the like. An accelerometer can be used. As such an acceleration sensor, more specifically, various 3-axis type piezoelectric acceleration detectors manufactured by Showa Sokki Co., Ltd., which can accurately detect the magnitude and frequency of vibration, are used. Can be used.

In the present embodiment, the acceleration sensor 14 preferably serves as the outer peripheral portion of the cutter head 13 so as to be close to the cutter bit 16a arranged on the outermost peripheral portion of the cutter head 13 and separated from the cutter bit 16a. It is attached to 13. That is, the acceleration sensor 14 is, for example, a 3-axis type piezoelectric acceleration detector, preferably the first detection direction is set along the excavation direction by the shield excavator 11, and the second detection direction is set by the cutter. It is attached to the back surface portion of the cutter bit 16a arranged on the outermost peripheral portion of the cutter head 13 in a state of being along the rotation circumferential direction of the head 13. Since the acceleration sensor 14 is attached close to the cutter bit 16a arranged at the outermost periphery of the cutter head 13 and separated from the cutter bit 16a, the ground on the face surface is cut by the cutter head 13. It becomes possible to appropriately measure the response acceleration (vibration data) at the time. Further, the maintenance of the acceleration sensor 14 becomes easy, and it is possible to avoid affecting the replacement work of the cutter bit 16a. The acceleration sensor 14 is connected to the acceleration sensor amplifier 25a via a connection cable 14a through a rotary joint.

Further, in the present embodiment, the auxiliary acceleration sensor 18 is attached to the back surface portion of the partition wall 17 that partitions the partition chamber 19 as the inner wall surface of the shield main body 15. Like the acceleration sensor 14, the auxiliary acceleration sensor 18 is, for example, a 3-axis type piezoelectric acceleration detector, preferably the first detection direction is set along the excavation direction by the shield excavator 11 and the second Is attached to the back surface portion of the partition wall 17 in a state where the detection direction is along the rotation circumferential direction of the cutter head 13. This makes it possible to efficiently and accurately measure and obtain the natural vibration data due to the vibration of the shield main body 15 when the shield excavator 11 is in operation. Further, the auxiliary acceleration sensor 18 is connected to the acceleration sensor amplifier 25b via a connection cable 18a. The vibration data of the main body from the auxiliary acceleration sensor 18 is sent to the computer 20 via the acceleration sensor amplifier 25b and the transmission system 29, so that the vibration data display unit 22 removes noise and mechanical vibration as described above. In this state, the vibration data for each rotation angle sent from the acceleration sensor 14 can be displayed as the cutting vibration distribution 23 in the circumferential direction.

Further, in the present embodiment, a tachometer (not shown) including, for example, a rotary encoder is attached to the center shaft 13a of the cutter head 13. The rotation angle measured by this tachometer is sent to the computer 20 via the transmission system 29, so that the vibration data measured by the accelerometer 14 when cutting the face surface 12 at the time of construction is subjected to a predetermined rotation. The vibration data storage unit 21 can store each angle.

Here, according to the present embodiment, the frequency Δθ of the measurement in the circumferential direction by the acceleration sensor 14 is Δθ = r / 60 from the time interval Δt of data collection and the rotation speed r (ppm) of the cutter head 15. It is determined by the formula of × Δt × 360 °. For example, when the shield excavator 11 is a small-diameter excavator with an outer diameter of about 2360 mm and the rotation speed is as fast as r = 2.3 (ppm), the measurement time interval Δt is 0.1. The frequency of measurement Δθ when set to seconds is 1.38 ° from Δθ = 2.3 / 60 × 0.1 × 360 °, so measurement is performed by the accelerometer 14 every 1.38 °. It will be.

Further, in the present embodiment, a contact switch (not shown) is installed on the center shaft 13a of the cutter head 13 in order to grasp the position θ ° of the acceleration sensor 14 in the circumferential direction of the cutter head 13. For example, the top end of the shield excavator 11 is set as a zero point, and the reset process can be performed every time the shield excavator 11 passes through the zero point.

In the present embodiment, the vibration data, which is the response acceleration at the time of construction measured at each predetermined rotation angle by the acceleration sensor 14, is preferably the main body measured by the auxiliary acceleration sensor 18 at the same timing as the measurement by the acceleration sensor 14. Along with the partial vibration data, it is output via the dedicated accelerometer amplifiers 25a and 25b, and the output signal passes through the control panel 26 and sequencer panel 27 and passes through the same transmission system 29 as other excavation management data. , Is sent to the operation control room 31.

Then, in the present embodiment, as described above, the vibration data obtained by the accelerometer 14 when the ground 12a, 12b, 12c is cut by the cutter head 13 of the shield excavator 11 at the time of construction at the construction site. By comparing with the cutting vibration data of each simulated soil layer 40 obtained in advance in the computer 20, for example, in an experimental facility away from the construction site, the ground 12a of the face surface 12 being cut, The soil quality of 12b and 12c is determined.

That is, in the present embodiment, for example, in the bit vibration test device 50 provided in the experimental facility, for example, as shown in FIGS. 2 to 5, the excavated soil collected when constructing the shaft 30 at the construction site and the construction site. Using the excavated residual soil collected from the excavation site around the above, a plurality of simulated soil layers 40 are sequentially formed so as to be replaced with the soil layer storage tank 51 (see FIG. 2). The cutter bit 16 is moved in the embedded state in each of the simulated soil layers 40 formed by being sequentially replaced, and the vibration data (response acceleration) generated when the cutter bit 16 is moved is collected by the acceleration sensor 14 and collected. The vibration data is acquired as cutting vibration data corresponding to each simulated soil layer 40. Further, the acquired cutting vibration data is taken into the computer 20 installed in the operation control room 31 via a wired or wireless communication means or via an external storage means such as a CD-ROM, and the vibration data storage unit 21 Therefore, it is stored in advance. When the ground 12a, 12b, 12c of the face surface 12 is actually cut by the cutter head 13, the vibration data (response acceleration) at the time of construction obtained by the acceleration sensor 14 is stored in advance to cut the simulated soil layer 40. By comparing with the vibration data, the soil quality of the ground 12a, 12b, 12c of the face surface 12 to be cut is determined by the front soil distribution determination unit 32.

Here, the cutting vibration data corresponding to each simulated soil layer 40 can be easily collected and acquired by using the bit vibration test apparatus 50 of the present embodiment shown in FIGS. 2 to 5. The bit vibration test device 50 of the present embodiment has a soil layer storage tank 51 having an opening surface 51a on the upper surface and a cutter bit, which can be accommodated by sequentially replacing the simulated soil layer 40 in a compacted state. 16 is detachably supported and fixed, and the bit fixing jig 52 to which the acceleration sensor 14 is attached and the bit fixing jig 52 are preferably placed inside the soil layer storage tank 51 in the lateral direction X along the opening surface 51a. Is configured to include a lateral moving device 53 for reciprocating movement and a depth direction moving device 54 for moving the bit fixing jig 52 in the depth direction Z inside the soil layer storage tank 51. The cutter bit 16 is embedded in the simulated soil layer 40 housed in the soil layer storage tank 51, and the cutter bit 16 is moved by the acceleration sensor 14 in the lateral direction X and the depth direction Z along the opening surface 51a. Vibration data (response acceleration) is collected.

The soil layer accommodating tank 51 constituting the bit vibration test apparatus 50 is preferably formed by assembling steel materials such as a steel plate, angle steel, and channel steel, for example, having a length of about 1700 mm and a width of about 300 mm. It is a hexahedron-shaped box with an opening surface 51a on the upper surface, which is provided inside with a soil layer storage portion 51b having an inner dimension of about 300 mm in height, and the influence of restraint by the soil layer storage tank 51 is contained. Care is taken not to reach the simulated soil layer 40. The soil layer storage tank 51 is formed in a rectangular frame-shaped mounting base 55 having external dimensions having a size of, for example, about 2800 mm in length and about 850 mm in width, which is formed by assembling a steel material such as H-shaped steel. , It is installed in a state where it is offset to one of the long sides. The excavation surplus soil collected when constructing the shaft 30 at the construction site and the excavation surplus soil collected from the excavation site around the construction site are put into the soil layer storage tank 51 and compacted to obtain cutting vibration data. A simulated soil layer 40 for obtaining the soil layer 40 is replaceably housed. On the other long side of the mounting pedestal 55 opposite to the side on which the soil layer accommodating tank 51 is installed, a moving device support pedestal 56 is provided from the mounting pedestal 55 along the side portion of the soil layer accommodating tank 51. It is installed in an upright position. A lateral moving device 53 that is supported by the moving device support pedestal 56 and moves the bit fixing jig 52 in the lateral direction X along the opening surface of the soil layer accommodating tank 51, preferably reciprocating, is attached.

In the present embodiment, the lateral movement device 53 constituting the bit vibration test device 50 includes known members such as a ball screw 53a, a horizontal drive servomotor 53b, a cable carrier 53c, and a contact switch (not shown). It is formed by assembling the device. The lateral movement device 53 guides the lateral movement base 57 including the bit fixing jig 52, which supports and fixes the cutter bit 16 to be tested for obtaining vibration data, to a pair of guide rails 53d so as to be detachably replaceable. The bit fixing jig 52 can be reciprocated in the lateral direction X along the opening surface of the soil layer storage tank 51, preferably in the length direction X of the soil layer storage tank 51 along the horizontal plane. It has become. That is, the lateral movement device 53 rotates the ball screw 53a arranged in parallel with the length direction X of the soil layer storage tank 51 in the forward direction or the reverse direction by driving the horizontal drive servomotor 53b. The lateral movement base 57 can be preferably reciprocated together with the bit fixing jig 52 in the length direction X of the soil layer storage tank 51 at a predetermined movement speed described later. The pair of guide rails 53d are installed on both sides of the ball screw 53a arranged in parallel with the length direction X of the soil layer accommodating tank 51, and the lateral movement device 53 is a known contact point. By switching the rotation of the ball screw 53a by the horizontal drive servomotor 53b in the forward direction or the reverse direction by the switch, the lateral movement base 57 is moved in the length direction of the soil layer accommodating tank 51 together with the bit fixing jig 52. It can be moved back and forth to X, preferably.

The laterally moving base 57 provided with the bit fixing jig 52 is formed by assembling steel materials such as a steel plate, angle steel, and channel steel, for example, having a vertical width of about 200 mm and a horizontal width of about 500 mm. Has a horizontally long rectangular planar shape. The lateral movement base 57 is arranged so as to straddle the pair of guide rails 53d by arranging the lateral width direction in the direction perpendicular to the length direction X of the soil layer storage tank 51, and also with the cable carrier 53c. Is attached in a state where the portion on the opposite side is projected above the opening surface 51a of the soil layer storage tank 51. The end of the lateral movement base 57 on the cable carrier 53c side is connected to the cable carrier 53c via a connecting angle member 57a. In the lateral movement base 57, the bit fixing jig 52 is moved in the depth direction Z inside the soil layer storage tank 51 to the portion protruding above the opening surface 51a of the soil layer storage tank 51, in the depth direction. A moving device 54 is provided. A bit fixing jig 52 that supports and fixes the cutter bit 14 so as to be detachably replaceable via the depth direction moving device 54 is laterally attached to the lateral moving base 57 along the opening surface 51a of the soil layer accommodating tank 51. It is attached to the direction X so that it can move, for example, in a straight line, preferably in a state where it can move back and forth.

In the present embodiment, the depth direction moving device 54 is formed by assembling known members or devices such as a screw jack 54a, a vertical drive servomotor 54b, a guide piston 54c, and a contact switch (not shown). ing. The depth direction moving device 54 is guided by a pair of guide pistons 54c composed of a guide sleeve 54d and a guide rod 54e, which are arranged vertically from the lateral moving base 57, and is guided by a vertical drive servomotor 54b. By expanding and contracting the screw jack 54a by driving the screw jack 54a, the bit fixing jig 52 attached by being connected to the lower end of the guide piston 54c and the screw jack 54a is detachably supported and fixed to the bit fixing jig 52. Together with the bit 16, the inside of the soil layer storage tank 51 can be moved up and down in the depth direction Z of the soil layer storage tank 51 at a predetermined movement speed described later.

The bit fixing jig 52 is processed and formed into a predetermined shape capable of stably supporting and fixing the cutter bit 16 to be tested for obtaining vibration data in a state of being hung downward. It is made of a thick steel plate and is provided with bolt fastening holes 52a (see FIG. 5) penetrating vertically at a plurality of locations. The cutter bit 16 is detachably and exchangeably fixed to the bit fixing jig 52 in a state of hanging downward via a bolt member 52b (see FIG. 5) that is fastened to the bolt fastening hole 52a. Further, the bit fixing jig 52 is the lower end of the guide rod 54e of the pair of guide pistons 54c of the depth direction moving device 54 and the lower end of the screw jack 54a via the bolt member 52b that is fastened to the bolt tightening hole 52a. It is fastened and fixed to a connecting plate 54f that integrally connects the portions (see FIG. 5). As a result, the bit fixing jig 52, together with the cutter bit 16 taken to the bit fixing jig 52, is driven by the depth direction moving device 54 to the depth of the soil layer accommodating tank 51 inside the soil layer accommodating tank 51. It can be moved up and down in the direction Z at a predetermined movement speed described later.

Further, in the present embodiment, the acceleration sensor 14 is attached to the upper surface side of the bit fixing jig 52 in a state of being close to the cutter bit 16 attached to the lower surface side and separated from the cutter bit 16. The acceleration sensor 14 is preferably a three-axis piezoelectric type similar to the acceleration sensor 14 attached to the cutter head 13 of the shield excavator 11 in close proximity to the cutter bit 14 in the above-mentioned face soil distribution determination system 10. An accelerometer can be used. The accelerometer 14 preferably sets the first detection direction along the depth direction Z of the soil layer storage tank 51, which corresponds to the direction of excavation by the shield excavator 11, and sets the second detection direction to the cutter head 13. It is attached to the bit fixing jig 52 in a state along the length direction X of the soil layer accommodating tank 51, which corresponds to the rotation circumferential direction of the above.

The accelerometer 14 is the above-mentioned bit vibration test device 50, in which the cutter bit 16 supported and fixed to the bit fixing jig 52 is preferably reciprocated while being embedded in the simulated soil layer 40. Therefore, it is preferable that 10 to 2000 points of vibration data can be collected per second, and more preferably 50 to 1000 points of vibration data can be collected per second. This makes it possible to obtain a Fourier spectrum by Fourier transforming the magnitude and frequency of the collected vibration data (response acceleration), and is investigating the difference in response acceleration of the simulated soil layer 40 for each soil type. Therefore, it becomes possible to analyze the characteristics of the ground more accurately.

In the present embodiment, the acceleration sensor 14 can collect vibration data (response acceleration) of 60,000 points per minute, for example, as one point every 1/1000 second. This makes it possible to collect extremely fine vibration data that reflects the size and shape of sand, soil, and stone particles that make up the simulated soil layer 40. Therefore, the acceleration sensor 14 preferably constitutes a measuring device incorporated in the operation control panel 60 installed on the mounting base 55, for example, having a measurement frequency of 1.0 μs and a maximum number of measurement points of 60,000. It is connected to a known data logger.

In order to obtain cutting vibration data of a plurality of simulated soil layers 40 from excavation residual soil collected from a construction site or an excavation site around the construction site using the bit vibration test device 50 having the above configuration, the collected excavation residual soil is used. By using, for example, a simulated soil layer 40 made of a clay layer, a sand layer, a gravel layer, or the like is formed in the soil layer storage portion 51b inside the soil layer storage tank 51, respectively. When forming these simulated soil layers 40, by adjusting the wet density and the degree of compaction of the clay layer, sand layer, gravel layer, etc., these simulated soil layers 40 are appropriately set so as to have a predetermined hardness. can do.

After that, the bit fixing jig 52 is moved downward by the depth direction moving device 54, and the cutter bit 16 to be tested for obtaining the vibration data is embedded in the formed simulated soil layer 40. In the embedded state, the lateral movement device 53 and the depth direction movement device 54 are driven to move the cutter bit 16 in the lateral direction X and the depth direction Z at the same time, and the accelerometer 14 is moved. The vibration data which is the response acceleration is collected by.

Here, the lateral moving device 53 attaches the cutter bit 16 supported and fixed to the bit fixing jig 52 to the soil in a speed range of, for example, 150 to 300 mm / sec, which corresponds to the rotation speed of the outer peripheral portion of the cutter head 13. The layer accommodating tank 51 can be reciprocated in a variable speed in the length direction X. Further, the depth direction moving device 54 is supported and fixed to the bit fixing jig 52 integrally attached to the lower end of the guide rod 54e of the pair of guide pistons 54c and the lower end of the screw jack 54a via the connecting plate 54f. The cutter bit 16 is moved downward in a variable speed in the depth direction Z in a speed range of, for example, 20 to 50 mm / min, which corresponds to the extension speed of the shield jack (digging speed of the shield excavator). You can do it. By moving the cutter bit 16 in the length direction X and the depth direction Z of the soil layer storage tank 51 in a variable speed, the performance and scale of the cutter head 13 of each shield excavator 11 used for the actual shield construction can be improved. It is possible to obtain the corresponding and more accurate cutting vibration data of the cutter bit 16, and the cutting of the cutter bit 16 is more accurate by reflecting the rotation speed of the cutter head and the excavation speed of the shield excavator as parameters. It becomes possible to obtain vibration data.

Further, in the present embodiment, the cutter bit 16 to be tested for obtaining vibration data can be supported and fixed to the bit fixing jig 52 so as to be detachably replaceable. By collecting vibration data for each of the reinforced leading bit, which is advantageous for the ground due to soil, and the leading bit used for the ground made of silty soil, clay, sandy soil, etc., the difference in the cutter bit is reflected as a parameter. It becomes possible to obtain more accurate cutting vibration data of the cutter bit 16.

As described above, these collected cutting vibration data are used as cutting vibration data corresponding to each simulated soil layer 40 via a wired or wireless communication means, or via an external storage means such as a CD-ROM. Then, it is taken into the computer 20 installed in the operation control room 31 and stored in advance by the vibration data storage unit 21.

Then, in the present embodiment, when cutting the ground in the ground with the cutter head 13 of the shield excavator 11 at the construction site of the shield construction, the above-mentioned discrimination system 10 is configured, preferably the outermost portion of the cutter head 13. Vibration data (response acceleration) during cutting is collected by the acceleration sensor 14 mounted close to the cutter bit 16a arranged in, and the collected vibration data is stored in advance in the computer 20 by the vibration data storage unit 21. By the cutter bit 16 while moving the cutter bit 16 in each simulated soil layer 40, which is stored, for example, in the above-mentioned experimental facility, preferably obtained by using the above-mentioned bit vibration test apparatus 50. By comparing with the cutting vibration data corresponding to each of the plurality of simulated soil layers 40 at the time of cutting, the soil quality of the grounds 12a, 12b, 12c of the face surface 12 being cut is determined.

In the present embodiment, the cutting vibration data corresponding to each of the plurality of simulated soil layers 40, which is stored in the computer 20 in advance by the vibration data storage unit 21, is such that each simulated soil layer 40 provides a shaft 30 at the construction site. It is formed by using the excavated soil actually collected at the time of construction and the excavated soil actually collected from the excavation site around the construction site, and the rotation speed of the cutter head 13 and the shield excavator 11 It is subdivided by reflecting the excavation speed, the difference in the cutter bit 16 and the like as parameters. As a result, according to the present embodiment, the vibration collected by the acceleration sensor 14 attached close to the cutter bit 16a arranged on the outermost peripheral portion of the cutter head 13 as in the conventional discrimination system and the judgment method. Compare the changes in the data with the results of a ground survey conducted in advance at the construction site, such as before excavation with a shield excavator, to determine the soil quality of the face surface. , It becomes possible to judge the soil quality of the ground on the face surface more accurately.

That is, according to the method for determining the face ground in the shield excavator of the present embodiment and the bit vibration test device 50, the difference in the rotation speed of the cutter head, the excavation speed of the shield excavator, and the cutter bit at the time of excavation of the shield excavator. Etc. can be reflected as parameters to more accurately determine the soil quality of the ground on the face surface.

The present invention is not limited to each of the above embodiments, and various modifications can be made. For example, the bit fixing jig that supports and fixes the cutter bit 14 so as to be detachably replaceable is attached to the lateral movement base in a state where it can be reciprocated laterally along the opening surface of the soil layer storage tank 51. It is not always necessary, and it may be attached so that it can be moved in only one direction, and the bit fixing jig is attached so that it can be moved linearly in the lateral direction along the opening surface of the soil layer storage tank. It is not always necessary to be attached, and it may be attached so that it can move in an arc shape corresponding to the rotation circumferential direction of the cutter head.

Hereinafter, the method for determining the face ground and the bit vibration test device in the shield excavator will be described in more detail by way of examples, but the present invention is not limited thereto.

Soil layer accommodation using RC40 crushed stone simulating clay, sand, and gravel ground using a bit vibration test device similar to the test device used in the above embodiment having the configuration shown in FIGS. 2 to 5. A simulated soil layer was formed in the tank 51 for each test. Further, as the cutter bit to be tested for obtaining vibration data, the reinforced leading bit (bit 1) shown in FIG. 6 (a), which is advantageous for the ground made of gravel soil, and silt soil, clay, and sand soil. The preceding bit (bit 2) shown in FIG. 6B, which is used for the ground due to the above, is replaced with the bit fixing jig 52 and attached, and the vibration data of each bit is collected. Table 1 shows an outline of the bit vibration test equipment used. Table 2 shows the experimental cases.

[Verification of differences in soil quality]
FIG. 7 shows the response acceleration due to the difference in soil quality of clay, sand, and RC40. The vertical axis shows the response acceleration (average in the X direction), and the horizontal axis shows the soil quality. Regardless of the difference in bits, the response acceleration of RC40 tends to be larger than that of clay and sand. In addition, clay and sand did not show a large difference in the evaluation of the average value of the response acceleration. From this, it is found that the difference in response acceleration depending on the soil quality is remarkably large in RC40, but not significantly different in sand and clay.

[Verification of differences in horizontal movement speed (speed in the X direction)]
8 to 10 show changes in response acceleration due to differences in horizontal movement speed (150 to 300 mm / s), with the response acceleration (average) on the vertical axis and the horizontal movement speed on the horizontal axis. .. It was confirmed that under all conditions, the response acceleration increased as the horizontal movement speed increased. FIG. 8 shows the result in clay, and the response acceleration in the X direction shows about twice the response acceleration in the Z direction. This tendency was the same with the sand shown in FIG. On the other hand, in the result of RC40 in FIG. 10, the difference in response acceleration depending on the bit shape is remarkably shown, but unlike clay and sand, there is no significant difference in the response acceleration in the X direction and the response acceleration in the Z direction. As a result, the horizontal movement speed is determined for each shield machine by the cutter sliding speed (diameter x rotation speed), and the movement speed-acceleration curve becomes linear for each soil type, resulting in a difference in the magnitude of acceleration. It is found that the data on the relationship between the response acceleration (average) and the horizontal movement speed shown in FIGS. 8 to 10 are effective data for soil quality discrimination.

[Re-verification of "difference between clay and sand" by Fourier spectrum]
The Fourier spectra of the Z-direction response acceleration measured for clay and sand are shown in FIGS. 11 and 12. Since the predominant frequency is prominent in the Fourier spectrum of sand, the verification by the Fourier spectrum is considered to be an effective means for finding the difference between clay and sand. It also reveals that the difference between clay and sand can be determined from the predominant frequency of the Fourier spectrum in response acceleration.

10 Face soil distribution discrimination system 11 Shield excavator 12 Face surface 12a, 12b, 12c Face ground 13 Cutter head 14 Accelerometer 15 Shield body 16 Cutter bit 16a Cutter bit 20 Computer 21 Vibration data placed on the outermost part Storage unit 30 Vertical shaft 31 Operation control room 32 Front soil distribution determination unit 40 Simulated soil layer 50-bit vibration test device 51 Soil layer storage tank 51a Opening surface 52-bit fixed jig 53 Lateral movement device 53a Ball screw 53b Horizontal drive servomotor 53c Cable carrier 53d Guide rail 54 Depth moving device 54a Screw jack 54b Vertical drive servo motor 54c Guide piston 54d Guide sleeve 54e Guide rod 54f Connecting board 55 Mounting base 56 Moving device support base 57 Lateral moving base X Soil layer accommodation Lateral direction along the opening surface of the tank (length direction of the soil layer storage tank)
Z Depth direction of soil layer storage tank

Claims (6)

A method for determining the face ground in a shield excavator equipped with a face soil distribution discrimination system including an acceleration sensor attached to a cutter head and a computer connected to the acceleration sensor, in which a shaft is constructed at a construction site. Using the excavated soil collected at the time or the excavated soil collected from the excavation site around the construction site, multiple simulated soil layers are formed, and a cutter bit is embedded and moved in each of the formed simulated soil layers. The vibration data at that time is collected by the acceleration sensor, and the collected vibration data is stored in advance in the computer as cutting vibration data corresponding to each simulated soil layer, and the ground is used by the cutter head of the shield excavator at the construction site. In a shield excavator that determines the soil quality of the face ground being cut by comparing the vibration data obtained by the acceleration sensor with the cutting vibration data of each simulated soil layer stored in advance. It is a bit vibration test device used when collecting cutting vibration data corresponding to each simulated soil layer in the judgment method of face ground.
A bit fixing jig that supports and fixes the soil layer storage tank with an open top surface that accommodates the simulated soil layer in a compacted state and the cutter bit so that it can be attached and detached, and an acceleration sensor is attached. And a lateral movement device that moves the bit fixing jig in the lateral direction along the opening surface inside the soil layer storage tank, and a bit fixing jig is moved in the depth direction inside the soil layer storage tank. It is configured to include a depth direction moving device.
Bit vibration that collects vibration data by the acceleration sensor while embedding the cutter bit in the simulated soil layer housed in the soil layer storage tank and moving it in the lateral direction and the depth direction along the opening surface. Test equipment. The bit vibration test device according to claim 1, wherein the lateral movement device is capable of reciprocating the bit fixing jig in the lateral direction along an opening surface inside the soil layer storage tank. The bit vibration test device according to claim 1, wherein the bit fixing jig can move the bit fixing jig linearly in the lateral direction along an opening surface inside the soil layer storage tank. .. The bit vibration test apparatus according to any one of claims 1 to 3, wherein the cutter bit can move in a variable speed in the lateral direction and the depth direction. The bit vibration test apparatus according to any one of claims 1 to 4, wherein the bit fixing jig supports and fixes the cutter bit so as to be detachably replaceable. The cutter bit, which is detachably supported and fixed to the bit fixing tool, is a reinforced leading bit which is advantageous for the ground made of gravel soil and a leading bit used for the ground made of silt soil, clay, or sandy soil. The bit vibration test apparatus according to claim 5, including the above.

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