JPS594028B2 - Collapse detection method in shield tunneling machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting ground collapse during tunnel excavation in a shield tunneling machine.

When excavating a tunnel using a shield tunneling machine, detecting the gap between the machine body and the ground, i.e. the amount of over-excavation of the ground or the amount of ground collapse, and responding promptly will prevent ground subsidence and ensure safe tunnel excavation. It is an element that can be done.

However, in mechanical excavation using a shield excavator, the face surface is often not visible because the cutter head is located at the front end, making it difficult to detect the degree of collapse of the ground face.

Furthermore, it is difficult to detect the amount of clearance between the shield tunneling machine and the surrounding ground.

For this reason, in excavation using a conventional shield tunneling machine, it is not possible to prevent ground collapse or subsidence in advance, and there is a problem that tunnel excavation cannot be performed with sufficient safety.

The present invention was made to solve the problems that occurred during excavation with the conventional shield excavator, and its purpose is to determine the amount of gaps around and in front of the excavator, the degree of collapse, and the location of the collapse. The present invention aims to provide a collapse detection method in which the amount of over-excavation of the ground and the amount of collapse can be detected at an early stage by using fluid, and safety measures can be easily taken during excavation.

Next, based on the attached drawings showing embodiments of the method of the present invention,
The details are as follows.

In the figure, 1 is the main body of a shield excavator, which excavates earth and sand from the ground by rotating a cutter head 2 attached to the front.

The earth and sand excavated by the cutter head 2 passes through a cutter slit 3 provided in the head 2, is taken into a pressure chamber 4 within the cutter head, and is discharged by a screw conveyor 5 while maintaining face pressure.

The cutter head 2 is rotated by a hydraulic motor 6, and if the earth and sand taken in by the cutter head 2 have poor fluidity, the pressure chamber 4 may not be completely filled with earth and sand, as shown in Figure 1. As shown in the figure, a collapsed portion 7 will occur in the ground of the face.

Further, even if groundwater is retained when the pressure chamber 4 is not filled with earth and sand, a similar collapsed portion 7 will occur due to replacement of ground water and earth and sand on the ground wall.

In order to detect the above-described collapsed portion 7 during excavation, a nozzle 8 is attached to the cutter head 2, and a nozzle 8 is attached to the cutter head 2.
A compressed air source 9 and a nozzle 8 installed inside are connected via piping 10 and a rotary joint 11.

A flow rate indicator 1 is installed in the middle of the piping 10 starting from the nozzle 8.
2. Install the pressure gauge 13 and regulator 14.

During excavation, the compressed air sent from the compressed air source 9 is ejected from the nozzle 8. The compressed air ejected from the nozzle 8 has a flow rate according to the gap between the nozzle 8 and the collapsed portion 7 that has occurred in the face ground. changes, and the gap measurement can be detected by reading the height l of the flow rate indicator 12.

In the method of detecting the gap in the collapsed portion 7 based on the flow rate of air, the following equation holds true.

Outflow amount: Q Coefficient: d Pressure crab p1 Nozzle diameter: d2 Q=d・πd2・h−J lower.

As mentioned above, the air flow rate changes depending on the gap between the collapsed portion 7 that occurs between the cutter head 2 and the face ground.
By measuring the rotation of the cutter head 2 and the air flow rate, the position of the collapsed portion 7 can be detected.

In addition, by installing the nozzles 8 around the shield excavator body 1 that is hit by the cutter head 2, it is possible to detect the gap between the main body 1 and the ground, and in either case, any number of nozzles 8 can be installed. It is something that can be done.

In addition, although the example shows the case where air is used as the gap detection fluid, the fluid is not limited to air in any way, and depending on the model of the shield excavator and the condition of the ground, it may be possible to use water or other fluids with high specific gravity. Fluids that are not harmful to the ground can be used, such as muddy water.

Furthermore, although the embodiment has shown a method of detecting the gap amount based on the flow rate of the fluid, it is also possible to implement a method that uses the pressure of the fluid to detect back pressure, differential pressure, etc., or a method that uses the flow velocity for detection. It is something.

Furthermore, in the illustrated embodiment, the pressure chamber 4 in the cutter head
The explanation has been based on a shield excavator in which excavated earth and sand from the ground are taken in, and in this case, the groundwater pressure is maintained in the pressure chamber 4, and the taken earth and sand also fills the pressure chamber 4. It is possible to use a method in which water or muddy water is strongly supplied from outside the machine body to counteract groundwater.

As described above, the present invention allows fluid to flow out from a part of the shield tunneling machine into the tunnel ground, and the amount of gap created between the tunnel ground and the shield tunneling machine due to changes in the flow rate, flow velocity, or pressure of this fluid. Since the system detects the amount of collapse and collapse, when excavating a tunnel with a shield excavator,
It is possible to detect the extent and location of gaps and collapses that have occurred between the excavator and the ground, and based on this detection, safety measures can be taken promptly during excavation, making it possible to prevent excavation using a shield excavator. It has an excellent effect that greatly contributes to improving work safety.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a vertical side view of the shield tunneling machine, FIG. 2 is a front view showing the cutter head portion of the same, and FIG. 3 is a part 1 of the detection mechanism. It is an explanatory diagram. 1 is the shield tunneling machine body, 2 is the cutter head, 3 is the slit, 4 is the pressure chamber, 7 is the collapsing part, 8 is the nozzle, 9 is the compressed air source, 12 is the flow rate indicator, 13 is the pressure gauge, 14 is the regulator .

Claims (1)

[Claims] 1 Fluid flows out into the tunnel ground from a part of the shield excavating machine that excavates the tunnel ground by rotation of the cutter head, and the gap between the tunnel ground and the shield excavating machine is created by changing the outflow flow rate, flow velocity, or pressure of the fluid. A method for detecting collapse in a shield excavator, characterized by detecting the amount of ground collapse.