JP2013002197A - Boring state monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boring state monitoring system which enables real-time transmission even in slurry and cement milk with high radio wave attenuation and reduces cost and eliminates the trouble of battery replacement for users.SOLUTION: A sensor and a transmission node are mounted on a boring head, and a relay node is mounted on a rod so that the measurement information on a cement milk concentration and others measured by the transmission node with the sensor is radio packetized and is transmitted to a ground monitor. If the sensor is mounted also on the relay node of each rod, the cement milk concentration distribution in a bored hole can be obtained without moving the boring head. Mounting of a vibration sensor can save power during the time zone in which work is not performed.

Description

  In the present invention, in order to grasp the excavation situation and the concentration of cement milk immersed in the excavation hole in near real time, the measurement information acquired by the sensor mounted on the excavation head and rod is used to monitor the ground. The present invention relates to an excavation state monitoring system for transmission.

  In pile foundation construction, an excavation hole (boring hole) for driving a pile is dug deep into the ground, but it is necessary to confirm that it is a desired excavation hole. In addition, when cement milk is poured into the borehole, it is necessary to confirm whether the cement milk concentration in the borehole is appropriate.

Therefore, a wired system and a wireless system are used as a system in which a sensor is mounted on an excavation head or a rod, and measurement information acquired by the sensor is transmitted to a monitoring device on the ground.
The wired system is a method of transmitting measurement information to a ground monitoring device using a wired cable such as a coaxial cable. Although the wired system has the advantage that the power of the sensor can be supplied from the ground, it is necessary to add the wired cable every time the rods are connected in cascade during excavation work.

  Among the wireless systems, the so-called low-frequency magnetic field method, which uses magnetic coupling with a low frequency frequency of several tens of kHz, transmits measurement information measured by a sensor to a low-frequency magnetic field signal and then transmits it to the ground using a transmission coil. It is a method to do. On the ground, a low-frequency magnetic field signal is detected by a receiving coil, and measurement information is extracted and then notified to the monitoring device. There are devices that generate large sources of radio noise, such as large generators for pile foundation construction. In this low-frequency magnetic field method, a low-frequency magnetic field is used, but due to the radiation interference electromagnetic field from the device, interference interference is given to the low-frequency magnetic field signal for transmitting measurement information, and many errors occur in measurement data transmission. Furthermore, since a low frequency frequency of several tens of kHz is used, the signal transmission speed that can be transmitted is lowered, and as a result, the transmission capacity is also small. These radiation interference electromagnetic fields and transmission capacity problems are obstacles to reliable real-time transmission of measurement information.

  In the wireless system using a radio frequency of several MHz or more, measurement information is stored in a wireless packet and transmitted to a ground monitoring device. Specifically, a specific power saving radio or weak radio is used. However, since radio wave attenuation is large in muddy water and cement milk, it is difficult to directly transmit from the drilling head to the monitoring device. Therefore, Patent Document 1 discloses means for transmitting measurement information to a monitoring device by using a plurality of relay nodes and multihopping wireless packets.

JP 2003-314179 A

  Patent Document 1 installs relay nodes at the upper end and lower end of a rod, and connects the upper end relay node and the lower end relay node with a wired cable so that the measurement information received at the relay node at the lower end of the rod And a relay node at the upper end of the rod, and the relay node at the upper end of the rod retransmits the measurement information. If the transmission system of patent document 1 is used, even when rods are connected in cascade, an extension work like a wired system is not required when the rods are added.

However, since the transmission system of Patent Document 1 requires two relay nodes per rod, there is a problem that the cost of the relay nodes increases as the depth of digging is increased. Furthermore, since the relay node is premised on battery activation, there is a problem that it takes time to replace the battery by the number of relay nodes.
Further, when the number of hops (the number of relays) of the relay node increases, there is a problem that the transmission delay of the measurement information increases in proportion.

  The object of the present invention is to solve the above-mentioned problems, and in the excavation state monitoring system using a wireless system in order to grasp in real time the excavation situation and the cement milk concentration immersed in the excavation hole in the pile foundation construction, the radio signal An object of the present invention is to provide an excavation state monitoring system that has high communication reliability, transmits measurement information to a monitoring device with a small delay, and is easy to maintain and inexpensive, even in muddy water and cement milk with large attenuation.

  In pile foundation construction that builds a drilling hole by transmitting power to the deepest drilling head through a rod connected in cascade from a motor on the ground, a sensor for grasping the drilling status and cement milk concentration in the drilling head; A transmission node is installed, a relay node is installed on the rod, and a reception node and a monitoring device are installed on the ground, so that a radio packet including measurement information measured by the transmission node using a sensor is attached to the rod. It is a transmission method of measurement information that multihop-transmits to the receiving node on the ground through the relay node that is mounted, the relay node arranges antennas at least at the upper end and lower end of the rod, and the lower end antenna installed at the lower end, or By retransmitting the wireless packet received by the upper end antenna installed at the upper end of the rod, Even for muddy water and cement milk with large radio signal attenuation, maintenance is easy by reducing radio signal transmission errors, high communication reliability, low transmission delay, and reducing relay information in the rod. And an inexpensive excavation condition monitoring system.

  According to the present invention, labor for battery replacement can be reduced. Furthermore, there is an effect that the transmission delay of measurement information can be reduced even when the number of relays is large.

1 is a block diagram of an excavation state information transmission system in Embodiment 1. FIG. 3 is a block diagram of a relay node 2 in Embodiment 1. FIG. 6 is a block diagram of a relay node 2 in Embodiment 2. FIG. FIG. 10 is an operation flowchart of the relay node 2 in the third embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

<Description of FIG. 1>
FIG. 1 is a block diagram of the excavation state information transmission system according to the first embodiment. The excavation head 41, the rod 31, the transmission node 1, the relay node 2, the reception node 3, the monitoring device 4, and the sensor 61 are illustrated. It has.

<Drilling head>
The excavation head 41 is for excavating a pile hole, and power is transmitted from the motor on the ground to the excavation head 41 through the rod 31. However, FIG. 1 omits the description of the motor on the ground. The excavation head 41 can be excavated to a predetermined depth by rotating with the power transmitted from the motor. After excavation, a pile is driven into the excavation hole 51 excavated by the excavation head 41, and further cement milk is poured.

<Rod>
The rod 31 transmits the power of the ground motor to the excavation head 41. Since the length of the rod 31 is about 10 m, it is necessary to connect the rod 31 in cascade every time the excavation proceeds. FIG. 1 shows an example in which rods 31 are arranged in two stages.

<Sending node>
The transmission node 1 performs measurement processing of the excavation status and the cement milk concentration at a predetermined cycle using the sensor 61. Further, the transmission node 1 transmits data obtained by the measurement process at a predetermined cycle from the antenna 12 as a wireless packet.
<Sensor>
The sensor 61 is used to measure the excavation status and the cement milk node, and is connected to the transmission node 1.

<Antenna>
The antenna 11 is connected to the transmission node 1 and transmits a wireless packet toward the lower end antenna 12 of the relay node 2. Therefore, the directivity of the antenna 11 is the direction of the antenna 12 provided at the lower end of the relay node 2.
Further, since the inside of the excavation hole 51 is immersed in muddy water or cement milk, the radio wave attenuation is large, and the transmission distance of the wireless packet is about several tens of centimeters. Therefore, since the transmission distance of the wireless packet is sufficiently shorter than the length of the rod 31, the wireless packet transmitted from the antenna 12 can be received by the lower end antenna 12 of the relay node 2, but is received by the upper end antenna 13. It is difficult.

<Relay node>
A wireless packet including measurement information transmitted from the antenna 12 of the transmission node 1 is received by the lower end antenna 12 of the rod 31. The packet received by the antenna 12 is transmitted to the relay node 2 and retransmitted by the relay node 2 via the upper end antenna 13.
Details of the configuration of the relay node 2 will be described below.
FIG. 2 is a block diagram of the relay node 2 in the first embodiment. The relay node 2 includes a wireless module 101, a combiner / distributor 102, a lower end antenna 12, an upper end antenna 13, and a coaxial cable 21.

<Wireless module>
The wireless module 101 has a function of retransmitting to the other relay node 11 and the receiving node 3 after receiving the wireless packet including the measurement information transmitted by the transmitting node 11 and the other relay node 2.

<Bottom antenna>
The lower end antenna 12 is an antenna attached to the lower end of the rod 31, from a radio packet transmitted from the antenna 11, or from the upper end antenna 13 of the relay node 2 mounted on the rod 31 one step below the rod 31 connected in cascade. Used to receive transmitted wireless packets. Therefore, the directivity of the lower end antenna 12 is the direction of the upper end antenna 13 of the relay node 2 mounted on the antenna 11 or the rod 31 one step below the rod 31 connected in cascade.

<Top antenna>
The upper end antenna 13 is an antenna attached to the upper end of the rod 31, and is directed toward the lower end antenna 12 of the relay node 2 mounted on the rod 31 on the first stage of the rod 31 connected in cascade and the antenna of the reception node 3. Send a wireless packet. Therefore, the directivity of the upper end antenna 13 is the direction of the lower end antenna 12 of the relay node 2 mounted on the rod 31 on the first stage of the rods 31 connected in cascade and the reception node 3.
As described above, since the inside of the excavation hole 51 is immersed in muddy water or cement milk, the radio wave attenuation is large, and the transmission distance of the wireless packet is about several tens of centimeters. Therefore, since the transmission distance of the wireless packet is sufficiently shorter than the length of the rod 31, the wireless packet transmitted from the upper end antenna 13 can be received by the lower end antenna 12 of the rod 31 on the upper stage. 13 is difficult to receive.

<Synthetic distributor>
The combiner / distributor 102 has three connection ports, a connector a, a connector b, and a connector c, and outputs a signal input from the connector a and the connector b from the connector c after combining, and conversely from the connector c. It has a function of distributing and outputting input signals from the connector a and the connector b.
The connector a of the combiner / distributor 102 is connected to the lower end antenna 12, the connector b is connected to the upper end antenna 13, and the connector c is connected to the wireless module 101. However, the combiner / distributor 102 and the lower end antenna 12 do not need to be directly connected, and are connected via the coaxial cable 21 according to the length of the rod 2. Similarly, the combiner / distributor 102 and the upper end antenna 13, and the combiner / distributor 102 and the wireless module 101 are also connected via the coaxial cable 21.
Since the combiner / distributor 102 has a function of combining the signals input from the connector a and the connector b and then outputting them from the connector c, for example, when radio waves having opposite phases are input from the connector a and the connector b, We are weakening each other.

However, as described above, since the inside of the excavation hole 51 is immersed in muddy water or cement milk, the radio wave attenuation is large, and the transmission distance of the wireless packet is about several tens of centimeters. Since the length of the rod 31 is sufficiently long with respect to the transmission distance, it is difficult to receive the radio packet received by the lower antenna 12 with the upper antenna 13, and conversely, the radio packet received with the upper antenna 13 is lower. It is difficult to receive with an antenna. Accordingly, there is no problem because the same radio wave is not input simultaneously at the connector a and the connector b.
As described above, when the lower-end antenna 12 receives the wireless packet including the measurement information transmitted by the transmission node 1 or the other relay node 2, it is transmitted to the wireless module 101 via the combiner / distributor 102. The wireless module 101 that has received the measurement information transmits the measurement information to another relay node 101 via the combiner / distributor 102.

<Receiving node>
The receiving node 3 has a function of notifying the monitoring device 4 when a wireless packet including measurement information transmitted by the relay node 2 is received. Here, the receiving node 3 and the monitoring device 4 are connected by a wired communication path such as a LAN cable 22 or a wireless communication path.
However, when the excavation head is near the ground surface and the rod 31 is not used, the wireless packet transmitted from the antenna 12 of the excavation head 41 is received by the reception node 3 without passing through the relay node 2. .

<Monitoring device>
The monitoring device 4 displays the measurement information notified by the receiving node 3 as a graph or a numerical value so that an operator can easily see the measurement information. The operator can grasp the state of the excavation head 41 inside the ground and the cement milk concentration in the excavation hole 51 by looking at the screen of the monitoring device 4.

<Series of operations>
Next, a series of operations in Example 1 will be described. The transmission node 1 performs measurement processing using a sensor at a predetermined cycle. The measured information is transmitted from the antenna 11 as a wireless packet. Here, as a wireless method to be used, any method such as weak wireless or specific power saving may be used. However, since the radio wave attenuation in muddy water and cement milk is larger than in air, the one with lower frequency is better. desirable.
The wireless packet transmitted from the antenna 11 is received by the lower end antenna 12 of the relay node 2. As described above, the radio wave attenuation in the muddy water and cement milk is larger than that in the air, so that the lower end antenna 12 of the relay node 2 is preferably as close to the antenna 11 of the excavation head 41 as possible.
The wireless packet received by the lower end antenna 12 of the relay node 2 is transmitted to the wireless module 101 via the combiner / distributor 102.

The wireless module 101 reads the measurement information from the received packet, newly writes the measurement information in the wireless packet, and then performs transmission processing. As described above, the wireless packet transmitted from the wireless module 101 is transmitted from both end antennas of the lower end antenna 12 and the upper end antenna 13, but the upper end antenna 13 does not receive the wireless packet transmitted from the lower end antenna 12. On the other hand, the wireless packet transmitted from the upper end antenna 13 is received by the lower end antenna 12 of the relay node 2 mounted on the rod 31 at the upper stage.
By repeating the above operation, it is possible to transmit the wireless packet transmitted from the transmission node 1 to the ground by connecting several stages of rods in cascade.

On the ground, when the receiving node 3 receives the radio packet, the measurement data is extracted and notified to the monitoring device 4. The receiving node 3 and the monitoring device 4 are connected by a LAN cable or other wireless / wired cable.
The monitoring device 4 displays the measurement information received from the receiving node on a screen on the monitoring device after digitizing or graphing the measurement information so that the worker can easily grasp it. Alternatively, although not shown in FIG. 1, the monitoring device 4 may directly control an electric motor on the ground, which is a power source of the excavation head 41, or a generator that generates an operation power supply.

<Supplement of antenna>
During excavation, in order to reduce friction of the excavation head 41, the excavation hole 51 is immersed in mud water. Furthermore, after excavation, it is immersed in cement milk. Muddy water and cement milk have a higher electrical conductivity and a higher radio wave attenuation than air, so the transmission distance of wireless packets is about several tens of centimeters.
Therefore, it is desirable that the antenna 11 of the transmission node 1 and the lower end antenna 12 of the relay node 2 be as close as possible. Similarly, it is desirable that the upper end antenna 13 of the relay node 2 and the lower end antenna 12 of the other relay node 2 and the upper end antenna 13 of the relay node 2 and the antenna of the receiving node 3 be as close as possible.
In addition, the antenna 12, the lower antenna 12, and the upper antenna 13 are used in muddy water or cement milk, and therefore need to be waterproofed. Further, the antenna 12, the lower antenna 12, and the upper antenna 13 should be made strong so that they are not damaged by contact with a rock or the like during excavation Is desirable.

<Supplement of cable>
Since the rod 31 is about 10 m, when the relay module 2 is installed in the center of the rod 31, the lower end antenna 12 and the upper end antenna 13 need to be connected using the wired cable 21. The wired cable 21 is preferably a low loss cable such as a coaxial cable. Moreover, in order to prevent breakage of the wired cable 21 due to contact with rocks or the like during excavation, it is desirable to place the cable in a protective conduit.

<Supplement to Example 1>
In the first embodiment, a specific example of a system in which a multi-hop from a transmitting node is performed by a plurality of relay nodes 2 and then transmitted to a receiving node 3 on the ground is described. However, the state of the relay node 2 and the transmitting node 1 from the monitoring device 4 When controlling the above, it is sufficient to perform the reverse operation of the first embodiment.
In the first embodiment, only the transmission node 1 is connected to the sensor 61 and the measurement process is periodically performed. However, a sensor may be connected to the relay node 2 and the measurement process may be performed periodically.
In the embodiment described above, one relay node is provided for each rod 31, so that cost, transmission delay due to relay, and labor for the operator to replace the battery can be reduced.

  In the first embodiment, a system for transmitting a wireless packet including measurement information transmitted from the transmission node 1 to the reception node 3 on the ground via a plurality of relay nodes 2 is described. In the second embodiment, an example in which the sensor 301 is connected not only to the transmission node 1 but also to the relay node 2 will be described. Since the sensor 301 is connected not only to the transmission node 1 but also to the relay node 2, an example in which the excavation status and cement milk concentration can be grasped in more detail will be described below.

<Description of FIG. 3>
FIG. 3 is a block diagram of the relay node 2 in the second embodiment. However, the combiner / distributor 102, the lower antenna 12, the upper antenna 13, and the wired cable 21 have the same functions as those in FIG. The sensor 301 is connected to the wireless module 101.

<Functions of wireless module>
The wireless module 101 has a function of relaying a wireless packet including measurement information, performs a measurement process using the sensor 301 at a predetermined cycle, and transmits the measurement result as a wireless packet to the receiving node 3 as a transmission destination. . At this time, as in the first specific example, it is not necessary for the relay node 2 and the receiving node 3 to directly transmit and receive wireless packets, and it is only necessary that wireless packets can be exchanged via a plurality of relay nodes 2.

<Effect>
As an example of the effect of the second embodiment, a case where a cement milk concentration measurement sensor is used for the sensor 61 connected to the transmission node 11 and the sensor 301 connected to the relay node 2 will be described.
In the first embodiment, when measuring the cement milk concentration, since the cement milk concentration measurement sensor is connected only to the excavation head 41, in order to grasp the cement milk concentration distribution in the excavation hole 51, the transmission node It is necessary to measure the cement milk concentration while moving 1 up and down in the excavation hole 51. On the other hand, in Example 2, since the cement milk measurement sensor is also connected to the relay node 2, it is possible to measure the concentration distribution in the cement milk in the excavation hole 51 without moving the excavation head 41 up and down. Become.

In the second embodiment, by connecting the sensor not only to the transmission node 1 but also to the relay node 2, the concentration distribution in the cement milk in the excavation hole 51 is more detailed than when the sensor is connected only to the transmission node 1. It is possible to measure.
In the third embodiment, power is saved by using a vibration detection sensor as the sensor 61 connected to the transmission node 1 and the sensor 301 connected to the relay node 2 by utilizing the fact that vibration is always generated during the foundation construction work. I will write about the conversion.

<Description of FIG. 4>
FIG. 4 is an operation flowchart of the relay node 2 according to the third embodiment. Hereinafter, Example 3 is demonstrated using FIG.
<A series of relay node operations>
When the excavation state information transmission system is powered on in step S401, the relay node 2 transitions to the active mode in step S402. The active mode described here is a state in which all the functions of the wireless module 101 are operable. When a wireless packet transmitted by the transmitting node 1 or another relay node 2 is received, a function for retransmitting is determined in advance. It has a function of determining whether or not excavation is in progress by detecting whether or not vibration is generated using the vibration detection sensor 301 at a given cycle.

If the wireless module 101 receives a wireless packet transmitted from the transmission node 1 or another relay node 2 in step S403 (YES in the figure), the wireless module 101 receives another relay node 2 or reception in step S404. The wireless packet is retransmitted toward the node 2.
In step S405, the wireless module 101 performs vibration detection processing using the vibration detection sensor 301 at a predetermined cycle in the active mode. If no wireless packet is received in step S403 (NO in the figure), the process in step S403 is repeated.
In step S406, the monitoring device 4 determines the vibration detection result by the vibration detection process in step S405. If vibration cannot be detected for a certain period of time (YES in the figure), the monitoring device 4 determines that no foundation work is being performed, and causes the relay node 2 to transition to the sleep mode in step S407. If vibration is detected (NO in the figure), the process returns to step S403 and the process is repeated.

The sleep mode referred to here is a mode that suppresses battery consumption by operating only the interrupt detection function of the wireless module.
In step S <b> 408, the vibration sensor 301 performs vibration detection processing, and notifies the wireless module 101 of an interruption when vibration is detected. If the foundation construction work has been resumed and vibration is detected and the wireless module 101 is notified of an interruption (YES in the figure), the process returns to step S402, and the relay node 2 transitions to the active mode again. If vibration is not detected (NO in the figure), the determination in step S408 is repeated.
The above has described a series of operations of the relay node 2. However, the transmission node 1 also performs the same operation, and thus the description thereof is omitted.

<Effect>
As described above, since the transmission node 1 and the relay node 2 are premised on battery activation, it is necessary to suppress the consumption of the battery during a time zone (for example, at night) when the pile foundation construction work is not performed. In the third embodiment, a vibration detection sensor is used as the sensor 61 connected to the transmission node 1 and the sensor 301 connected to the relay node 2 using the fact that vibration is always generated during the foundation construction work. There is an effect of saving power by determining whether or not and exchanging to the sleep mode when excavation is not performed.

However, in the above, the vibration detection sensor is used for the sensor 61 and the sensor 301. However, as long as the vibration of the excavation head 41 and the rod 31 during the pile foundation construction work can be detected, a sensor such as an acceleration sensor other than the vibration sensor. May be used.
The embodiments described above do not limit the present invention. Embodiments in which constituent elements are changed or added to the respective embodiments can be considered, but all fall within the scope of the present invention.

  1: transmission node, 2: relay node, 3: reception node, 4: monitoring device, 11: antenna of transmission node, 12: lower end antenna of relay node, 13: upper end antenna of relay node, 21: wired cable, 31: Rod: 41: Drilling head, 51: Drilling hole, 61: Sensor, 71: Wireless communication distance, 101: Wireless module, 102: Composite distributor, 301: Sensor.

Claims (8)

An excavation state monitoring system for monitoring an excavation state of a borehole,
The excavation state monitoring system includes an excavation head that excavates the excavation hole, a rod that transmits power for driving the excavation head from the ground, and a reception node that receives transmission information related to the excavation state,
The drilling head is
A sensor for measuring information related to the excavation state;
A transmission node that performs a predetermined measurement process based on information related to the excavation state measured by the sensor and generates a wireless packet that is the transmission information;
An antenna for transmitting the wireless packet generated by the transmitting node;
The rod is
A first antenna for receiving the wireless packet;
A relay node that relays the wireless packet received by the first antenna;
A second antenna for transmitting the wireless packet relayed by the relay node;
When a plurality of the rods are provided in the excavation direction of the excavation hole,
Of the rods, the first antenna of the rod closest to the excavation head receives the radio packet transmitted by the antenna of the excavation head, and the second antenna receives the radio packet opposite to the excavation head. Transmit to the first antenna of the rod located on the side,
Receiving the radio packet transmitted by the second antenna of the rod of the rod closest to the receiving node of the rod, the first antenna of which is located on the opposite side of the receiving node; An excavation state monitoring system characterized by transmitting from an antenna to the receiving node.   The excavation state monitoring system according to claim 1, wherein the relay node of the rod includes a combiner / distributor that combines the wireless packets received by the first antenna or the second antenna, and the received wireless packets. An excavation condition monitoring system comprising a wireless module for re-transmission to another rod.   The excavation state monitoring system according to claim 1, wherein the sensor measures a cement milk concentration in the excavation hole.   The excavation state monitoring system according to claim 1, wherein the sensor measures vibrations in the excavation head.   The excavation state monitoring system according to claim 1, wherein the rod has a sensor that measures information related to the excavation state.   2. The excavation state monitoring system according to claim 1, wherein the transmission node of the excavation head has a sleep mode in which a transmission operation is stopped when it is not necessary to transmit transmission information related to the excavation state. Drilling condition monitoring system.   2. The excavation state monitoring system according to claim 1, wherein the relay node of the rod has a sleep mode in which a relay operation is stopped when it is not necessary to relay transmission information related to the excavation state. Condition monitoring system.   5. The excavation state monitoring system according to claim 4, wherein the transmission rod of the excavation head and the relay node of the rod have a sleep mode in which a transmission operation or a relay operation is stopped based on an amount of vibration in the excavation head measured by the sensor. An excavation state monitoring system comprising:

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