JPH0444678B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shield excavator equipped with a ground exploration function that detects soil changes in the ground in front of the excavator prior to excavation.

[Prior Art] There are various types of shield excavators depending on the execution conditions, such as mud pressure type, mud pressure type, mud water type, etc., but in the following explanation, the mud press type shield excavation machine will be mainly described.

A pressurized mud shield excavator uses a cutter wheel to excavate a face, fills the stirring chamber behind the cutter wheel with the excavated earth, and uses the propulsive force of the shield excavator to pressurize the earth and sand in the stirring chamber. The mechanism uses pressure to prevent the face from collapsing, while excavating the earth and sand that has filled the stirring chamber with a screw conveyor.

FIG. 2 is a side sectional view of a conventional mud pressurized shield excavator. In the figure, 1 is the shield body of the shield excavator, and the hood part 1a formed in the front
and a girder portion 1b formed at the rear.
2 is a bulk head that partitions the hood part 1a and the girder part 1b. 3 is a cutter wheel rotatably installed in the hood portion 1a, and this cutter wheel 3 has a central boss 3a, a boss 3a
A plurality of spokes 3b are attached radially to the spokes, stirring blades 3c are attached to the spokes 3b, and a center bit 3 is attached to the face side of the boss 3a.
d, a large number of bits 3e attached to the spokes 3b, and an injection port 3 provided on the boss 3a to inject mud preparation material such as bentonite solution toward the ground.
It is composed of f. A center shaft 4 is attached to the boss 3a and extends rearward. 5a, 5b, 5c are bearings for rotating the cutter wheel 3; 5a is a slide bearing supported by the bulkhead 2;
b is a slide bearing supported by the bearing case 6b, and 5c is a radial bearing supported by the bearing case 6b. 6 is a swing gear attached to the center shaft 4, 6a is a gear case attached to the bulkhead 2 and surrounds the swing gear 6, and 6b is a bearing case integrally formed on the rear surface of the gear case 6a. 7 is a drive device such as a hydraulic motor that is attached to the gear case 6a and drives the cutter wheel 3; 7a is a pinion that is attached to the output shaft of the drive device 7; the pinion 7a is connected to the rotating gear 6 in the gear case 6a; It fits. Reference numeral 8 denotes a stirring chamber formed in a cylindrical shape behind the cutter wheel 2. As is clear from the figure, the face side of the stirring chamber 8 is open, and the side opposite to the face is sealed by the bulkhead 2. 9 is the stirring chamber 8
10 is a screw conveyor whose intake port is the opening on the sealed side of the stirring chamber 8; 11 is attached to the bulkhead 2; The soil pressure gauge 12 used for measurement is a shield jack that provides a propulsion force to the shield body 1.

The shield excavator configured in this way transmits the driving force of the drive device 7 to the cutter wheel 3 via the swing gear 6 to rotate it, and the bits 3d, 3d,
Excavate the face with 3e. On the other hand, mud material is injected from the injection port 3f toward the face side and mixed into the excavated earth and sand. The excavated soil mixed with the mud-making material enters the stirring chamber 8, where both are sufficiently stirred by the stirring blades 3c and converted into mud with improved fluidity and impermeability. As a result, the excavated earth and sand reaches the inlet of the screw conveyor 10 without much resistance, and is conveyed to the outside of the machine by the screw conveyor 10. In this case, the pressure of the excavated soil filling the hood part 1a and the stirring chamber 8 is detected by the earth pressure gauge 11,
The earth pressure is maintained at an appropriate level based on the detected value.
(Earth pressure management).

[Problem that the invention seeks to solve]

Now, in the mud pressurized shield excavator as described above, a good mud condition must always be maintained in the stirring chamber 8 during excavation. This mud condition is determined by the properties of the injected mud material and excavated soil. If the excavated soil is clayey soil and the amount of mud material is too small, the mud condition will be excessively compositional and fluidity will deteriorate, making it difficult to remove the soil from the screw conveyor 10. (In short, this is what happens if the soil is such that it sticks). Also,
When the excavated soil is sandy soil, if the concentration of the mud material is too dilute, it will lose its plasticity and have poor fluidity, which may increase the stirring torque and even make it inoperable. As described above, in order to maintain a good mud condition, it is necessary to delicately control the concentration and flow rate of the mud preparation material, as well as the propulsion speed of the excavator, depending on the properties of the excavated soil. However, it is not always easy to maintain such good muddy conditions.
In other words, when the soil quality of the ground in front of the excavator changes from a sandy silt layer to a water-logged gravel layer, for example, as shown in Figure 3, the concentration and flow rate of the sludge material will be changed accordingly. Otherwise, a situation will occur in which water and sand will be ejected from the screw conveyor section. Once the muddy state is destroyed, it takes a considerable amount of time, effort, and skill to restore it.

In this way, it is important to control the concentration and flow rate of the sludge material in response to changes in the soil quality of the ground, but with the conventional shield excavator shown in Figure 2,
By observing the condition of the mud discharged from the screw conveyor 10, we can estimate the properties of the excavated soil in the stirring chamber 8 and the properties of the ground ahead.
Responses to the changes in soil quality mentioned above were delayed. This results in the eruption of water and sand as described above.

The above has described the mud pressure type shield excavator, but in the mud pressure type shield excavator, the chamber at the front of the excavator and the screw conveyor are filled with excavated earth to counteract the face earth pressure and the face water pressure. We have created plastic fluidization of filled earth and sand by generating earth pressure in the chamber and injecting lubricant depending on the soil quality.
In addition, in a mud water type shield excavator, mud water of a specified specific gravity and viscosity is fed and pressurized into the mud chamber at the front of the excavator to counter the face earth pressure and face water pressure, and the excavated earth and sand are stirred with the mud water. The method is to transport it to the ground. Therefore, in these methods as well, it is necessary to change the concentration and flow rate of the lubricant and mud water to be injected in response to changes in the soil quality of the ground, as in the case of the mud pressurization method described above. As described above, it is generally necessary for a shield excavator to excavate while predicting changes in the soil quality of the ground in front of the excavator, but no effective method for this has been realized so far.

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, it is an object of the present invention to provide a shield excavator having a function of detecting changes in the soil quality of the ground in front of the excavator before the excavator enters.

[Means for solving problems]

The above purpose is to provide an exploration rod that protrudes from the front part of the excavator and penetrates into the ground in front of it, and a built-in vibration sensor that converts vibrations generated when the rod penetrates into electrical signals into the exploration rod. This is achieved by including a processing device that processes sensor output signals and outputs soil information on the ground.

[Effect]

To explore the ground, a penetrating device such as a hydraulic cylinder attached to the excavator causes an exploration rod, which is always stored inside the excavator, to protrude from the front of the excavator and penetrate into the ground in front of it. Alternatively, the exploration rod, which is constantly protruding from the front of the excavator, is penetrated into the ground in front by using the propulsive force of the excavator itself provided by the shield jack. The vibration sensor built into the exploration rod converts the vibrations generated when the exploration rod penetrates into the ground into electrical signals, and the processing device processes this sensor output signal to obtain soil information about the ground. Output.

Next, the principle of this soil quality determination will be explained.

When a rod-shaped object is inserted into the soil, a kind of frictional sound can be heard as the rod breaks through the soil layer. This sound is the sound of the soil being crushed at the tip of the rod and the vibrations caused by friction with the rod, which are transmitted through the rod and propagated into the air above the ground. This sound varies depending on the soil quality, and in the case of clay it is usually so weak that it is almost inaudible.
It is quite loud in compacted sand and gravel, and in many cases, the characteristics of the sound can be distinguished and described as rasping, rasping, jiyari jiyari, siya siya, etc.

Focusing on this point, the inventors manufactured an exploration rod having a shape approximately shown in FIG. 4, which had a built-in microphone in its tip cone, and attempted experiments in which the rod was penetrated into soil of various soil types. As for the type of soil,
(1) Clay, (2) 70% river sand + 30% clay, (3) 80% river sand + 20% clay, (4) 90% river sand + 10% clay, (5) river sand, (6) river sand
70% + glass beads (gravel model) 30%, (7) river sand 50%
Eight types of glass beads (+50% glass beads) and (8) glass beads were selected, and the frequency of the sound collected by a microphone during penetration was analyzed. In Figure 5, the horizontal axis shows frequency (KHz).
The graph shows the frequency analysis results, with the sound pressure level plotted on the vertical axis. According to Figure 5, when the soil is mainly composed of clay, the sound pressure level is low and there is almost no sound, but as the sand content increases, the sound level increases. Case (4) is clearly different from case (1). moreover,
It can be seen that when gravel is mixed with sand, the sound pressure level becomes even higher.

From this result, it was found that soil quality can be estimated by examining the loudness of the sound when the rod penetrates, the range of its fluctuations, and the frequency of fluctuations.

In the above experiments, when the exploration rod penetrates into the soil, vibrations generated by the crushing of external soil particles or friction between soil particles and vibrations caused by friction between the tip cone of the rod and the soil are transmitted to the surface of the tip cone. The vibrations of the metal surface propagate through the metal that makes up the cone and reach the metal surface in front of the microphone's sensing surface, and the vibrations on the metal surface become pressure waves (longitudinal waves) that propagate through the air and are then sensed by the microphone. It is an indirect method for detecting vibrations. Therefore, by attaching an acceleration sensor or AE (acoustic emission) sensor to the metal surface of the tip cone,
It is also possible to determine soil quality by directly detecting vibrations propagating through metal and analyzing the sensor output signal, in the same way as by detecting sound with a microphone. In this specification, devices that detect vibrations generated when an exploration rod penetrates, whether directly or indirectly, and convert them into electrical signals are collectively referred to as vibration sensors. In addition, the soil quality information outputted from the processing device means information corresponding to the soil quality (or soil particle size), such as the magnitude of the detected sound (vibration), the range of fluctuation, the frequency of fluctuation, etc.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In the figure, the second
Components with the same functions and names as those in the figures are given the same reference numerals, and their explanations will be omitted.

13 is an exploration rod operated by a hydraulic cylinder type penetrating device. This exploration rod 13 is provided in the center shaft 4, and the large diameter portion 13 of the rod constitutes the piston of the hydraulic cylinder.
Hydraulic piping 15a is installed in the cylinder chamber 14 before and after a.
15b and hydraulic pressure paths 16a and 16b of the center shaft 4 connected thereto,
Slide to the left or right in the figure by discharging. In this embodiment, the exploration rod 13 is installed inside the rotating center shaft 4, so in order to prevent damage to the signal line of the vibration sensor, which will be described later, the exploration rod 13 is installed, although not shown in the drawings. 13 is prevented from rotating. A tip cone portion 17 containing a built-in vibration sensor is provided at the tip of the exploration rod 13 on the face side.

In order to show a specific example of the configuration of the vibration sensor, a detailed view of the vicinity of the tip of the exploration rod 13 is shown in FIG. 4. The tip cone portion 17 has a conical shape to facilitate penetration and prevent soil from adhering.
is attached to the main body of the exploration rod 13 with bolts 18. 19 is a microphone attached to the inside of the tip cone portion 17 with a screw 20;
This is shown as an example of a vibration sensor. The microphone 19 has a sensing surface with a tip cone portion 17.
When the exploration rod 13 penetrates into the soil, it collects the sound transmitted from the outer surface of the tip cone part 17 to the inner space. 21
is a signal line that passes through the inside of the exploration rod 13 to the rear driver's cab, and transmits the electric signal output from the microphone 19. In the driver's seat section, there is a processing device 2 that processes the output signal from the microphone 19 and presents information on the soil quality of the ground in front of the excavator to the driver.
2 is installed.

As for the configuration of the processing device 22, for example, after amplifying the output signal of the microphone 19 with a preamplifier,
The amplified signal is logarithmically compressed using a log amplifier and displayed on a sound pressure display as sound pressure, that is, the loudness of the sound. Furthermore, if necessary, a part of the signal amplified by the preamplifier is converted into a voltage proportional to the vibration frequency only for sounds exceeding a certain sound pressure level using a pulse counter, and the pulse count is displayed as a voltage proportional to the vibration frequency per unit time. It may also be displayed as the number of pulses. In this way, both the sound pressure and the number of pulses output from the processing device increase as the particle size of the soil increases, and it is possible to determine the soil quality based on this.

Next, the operation of this embodiment will be explained.

In Figure 1, it is assumed that the entire shield excavator is underground. In the shield construction method using a shield excavator, every time the tunnel excavates a predetermined distance (for example, 1 m), the excavation is interrupted in order to add a segment called a member that will become a part of the tunnel. For ease of explanation, it is assumed that the following operations are performed during this excavation interruption.

During segment construction, when pressure oil is supplied from the hydraulic pipe 15b, this pressure oil acts on the right side of the large diameter portion 13a of the exploration rod 13 in the figure through the hydraulic passage 16b, and its propulsive force causes the exploration rod 13 to move forward in the figure. Move to the center left. That is, the tip cone portion 17
protrudes from the front of the excavator and penetrates into the ground that has not yet been excavated. The penetrating sound generated at this time is detected by the microphone 19 in the tip cone portion 17, and is sent as an electrical signal to the processing device 22 via the signal line 21. As explained in the basic principle above, this penetration noise corresponds to the soil quality of the ground ahead, so the driver can check the output of this processing device 22, such as the magnitude of the penetration noise, the range of fluctuation, and the Depending on the frequency, etc., it is possible to know the soil quality of the ground that the excavator will enter from now on before entering, and if a change in soil quality is predicted, it will be possible to adjust the flow from the mud-making material supply pipe 23 to the injection port 3f. It becomes possible to prepare in advance the concentration and flow rate of the sludge material to be supplied to the tank.

FIG. 6 shows the state in which the exploration rod 13 has completed its penetration.

When the exploration rod 13 moves forward a predetermined distance (in this embodiment, by the stroke talk of the large diameter portion 13a constituting the piston), the pressure oil in the hydraulic pipe 15b is released. Then, wait for the completion of the segment construction work before starting excavation. As the excavation progresses, the exploration rod 13 is again pushed into the center shaft 4 by the excavation force and returns to the state shown in FIG. 1, that is, the retracted state.

In the above explanation of the operation, the exploration rod 13 is penetrated while the excavation machine is stopped, but the penetration operation is not limited to the time when excavation is stopped, but can be performed at any time during excavation.

Although the stroke of the exploration rod 13 is long in terms of predicting the soil quality of the ground ahead, considering the possibility of mechanical damage,
Approximately 1 to 2 segments would be appropriate. Also,
Considering that the excavation speed of the excavator is slow at a few cm/min, there is no need to explore the soil that far ahead.
The above level is considered to be sufficient.

In the above embodiment, the exploration rod 13 slides within the center shaft 4 and is configured to be able to explore the soil quality of the ground in front as needed. According to this, the exploration rod is not constantly exposed to the soil, so it has the advantage of being less likely to be damaged. In addition, since exploration can be performed while excavation is stopped, there is an advantage that only pure penetration sound can be detected without being affected by vibrations caused by excavation of earth and sand during excavation, that is, without noise from external vibrations being mixed in.

However, the gist of the present invention is not limited to the form of such a retractable exploration rod, but as shown in FIG. The technical scope of the present invention also includes a structure in which the exploration rod 13 is penetrated into the ground by the propulsion force generated when the shield body 1 moves forward by the operation of the shield jack 12, and the sound of the penetration is detected. (In Fig. 7, 24 is a fixing bolt for the exploration rod 13).

Furthermore, in the embodiment shown in FIG.
is placed in the center shaft 4, but if it is okay to limit the exploration while excavation is stopped, the exploration rod 13 can be placed inside the center shaft 4.
It may be configured such that it projects forward from the bulkhead 2 through between the spokes 3b of the cutter wheel 3 and the stirring blades 3c, or a probe for exploration may be placed on the outer periphery of the hood portion 1a that does not interfere with the rotation of the cutter wheel 3. A rod 13 can also be arranged.

In FIG. 8, 25 is a hydraulic cylinder for penetration attached to the outer periphery of the hood part 1a, 26 is a protective cover, 27 is an exploration rod with a built-in vibration sensor such as a microphone in its tip, and 28 is a protective cover 26.
A seal that prevents dirt and water from entering the interior.
Regardless of whether excavation is stopped or during excavation, when you want to explore the soil quality of the ground ahead, the hydraulic cylinder 25
This causes the exploration rod 27 to protrude from the front end of the hood portion 1a and penetrate into the ground in front.

FIG. 9 shows only the exploration rod 27 in the hood part 1.
In this example, the probe rod 27 is fixed to the outer periphery of the hood part 1a, and the tip of the probe rod 27 is always projected in front of the hood part 1a, and penetrates into the ground when the shield body 1 moves forward.

By protruding the exploration rod 27 from the outer periphery of the hood portion 1a as shown in FIGS. 8 and 9,
There is no restriction such as the cutter wheel 3 becoming stuck or being able to penetrate only when excavation is stopped, and the exploration rod can be moved to the center shaft 4.
There is no need to increase the diameter of the shaft unlike when it is installed inside the excavator, and the exploration rod can be installed without significantly changing the structure of other parts of the excavator. It is also possible to arrange multiple sets of hydraulic cylinders 25, exploration rods 27, etc. on the outer periphery of the hood part. For example, if four sets are installed on the top, bottom, left, and right sides, it is possible to arrange them in case of changes in the ground as shown in Fig. 3. The one installed at the bottom detects changes in the ground faster, and then detects from the left and right, and then the top. By doing so, it is possible to detect changes in the direction of the strata, making it possible to manage mud more precisely.

In the above embodiment, an example was explained in which the penetrating sound is detected by a microphone, but in FIG. The vibration propagating through the metal 17 may be directly detected. In addition, vibration sensors such as microphones, acceleration sensors, and AE sensors can be combined with one or more other sensors such as load cells that detect penetration resistance and pressure sensors that detect the water pressure of pore water in the soil to create exploration rods. By incorporating these signals into a system and processing those signals, it is possible to provide more information about the properties of the ground.

〔Effect of the invention〕

According to the present invention, changes in the soil quality of the ground in front of the excavator can be detected prior to excavation, and preparations can be made to change the concentration and flow rate of the mud-making material in response to the change. This has the effect that the mud condition in the stirring chamber of the machine can always be maintained in a good condition. The present invention also provides a mud pressure type shield propulsion machine that plastically fluidizes the filled earth by injecting a lubricant into the excavated earth filled in the chamber at the front of the excavation machine according to the soil quality, and a mud water chamber at the front of the excavation machine. The present invention can be similarly applied to a muddy shield excavator that pumps and pressurizes muddy water of a predetermined specific gravity and viscosity and transports it together with excavated soil, and the same effects as those described above can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of one embodiment of the present invention, showing the probe rod in a retracted state. Figure 2 is a side sectional view of a conventional shield tunneling machine, Figure 3 is an explanatory diagram of changes in the ground during excavation by the shield tunneling machine, and Figure 4 is an enlarged view of the tip of the exploration rod in Figure 1. 5 is an explanatory diagram of the principle of the present invention, FIG. 6 is a diagram showing the state in which the exploration rod of the embodiment shown in FIG. 1 has completed its penetration, and FIGS. 7, 8, and 9 are FIG. 7 is a side sectional view of another embodiment of the present invention in which the exploring rod has a different form. 1...Shield body, 1a...Hood part, 2...
...Bulkhead, 3...Cutter wheel, 4...
... Center shaft, 8 ... Stirring chamber, 13 ... Rod for exploration, 14 ... Cylinder chamber for penetration, 15
a, 15b...Hydraulic pipe, 17...Tip cone section, 19...Microphone (vibration sensor), 21
... Signal line, 22 ... Processing device, 25 ... Hydraulic cylinder for penetration, 27 ... Rod for exploration.

Claims (1)

[Scope of Claims] 1. An exploration rod that protrudes from the front part of the excavator and penetrates the ground in front, and a vibration sensor that converts vibrations generated when the rod penetrates into electrical signals is built into the exploration rod. , and a processing device that processes the sensor output signal and outputs soil quality information of the ground. 2. Claim 1, characterized in that the exploration rod is configured to be able to protrude in front of the excavator at any time by a penetration device attached to the excavator.
The shield excavator described in Section 1. 3. The shield excavator according to claim 1 or 2, wherein the exploration rod is arranged on the outer periphery of the hood portion of the shield body.