JPH0258697A - Hydraulic balance type force feed earth discharging shield construction method and shield excavator - Google Patents

Abstract

PURPOSE:To contrive stability in workability by supplying a hydraulic pressure higher than the groundwater level to a hydraulic chamber provided at the rear of a cutter head for excavating earth while stabilizing the working face, and by converting the earth and sand excavated into a high density slurry, so that it can be forcibly discharged towards the rearward. CONSTITUTION:A cutter head 5 on which a large number of cutters are projected is provided on the front of a shield body 1, and also a water supply pipe 10 is connected from a water supply tank 12 to a hydraulic chamber 1d formed behind the head 5, via a water supply pump 13. Further, to the chamber 1d, a closed earth discharging device 9 is connected via a screw conveyor 8. Thereby a hydraulic pressure higher than the groundwater level is supplied to the chamber 1d via the pipe 10 for stabilizing the working face, and also the shield jack for driving the body 1 forward and the device 9 are controlled, so that the earth and sand taken into the inside of the chamber 1d through the head 5 is reserved as a high density slurry of 50% to 90% by volume, and then is compressed and forcibly discharged towards the rearward. Thus, a stable workability can be provided.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is a hydraulically balanced pressure pumping system in which excavation is carried out while the face is stabilized by water pressure, and the excavated soil is turned into a highly concentrated slurry and then pumped backwards. This invention relates to an earth shield construction method and a shield excavator used in the method.

(Prior Art) Conventional shield construction methods for excavating tunnels using shield excavators include mud water balance shield construction methods and earth pressure shield construction methods.

The former mud water balance shield construction method injects pressurized mud water between the cutter head and the face during excavation to stabilize the face while excavating, and the excavated earth and sand is turned into a slurry and forced to be discharged backwards. It has become.

The latter earth pressure shield method stabilizes the face and excavates by filling the cutter head with excavated soil and preventing more earth and sand from flowing into the cutter head than necessary. At the same time, the excavated earth and sand is transported to the rear by an earth and sand conveying device such as a screw conveyor.

(Problem to be solved by the invention) However, while the mud water balance type shield construction method has excellent workability and durability of the shield excavator, etc., it requires a mud pipe that transports mud water, and a mud drainage system that transports earth and sand together with mud water. The entire system is expensive because it requires pipes, pump equipment for transporting and discharging mud, and mud water treatment equipment that solidifies the discharged mud water on the ground. Since it requires space for installation, it is difficult to install it in places where space cannot be secured.

In addition, although the earth pressure shield method is cheaper as a whole than the mud/water balance shield method, it has poor workability such as difficulty in stabilizing the face, and the cutter head cannot be used with the three cutter heads filled with earth and sand. Because the cutter excavates by rotating, it has short lifespan, making it unsuitable for long-distance construction.

This invention was made for the purpose of improving the above-mentioned problems, and is used for the hydraulic balance type pumping earth removal shield method and its construction method, which has stable workability equivalent to the mud water balance type shield method and can be constructed over long distances. The aim is to provide a shield tunneling machine that can

(Means and Effects for Solving the Problems) In order to achieve the above object, the present invention propels a cutter head for excavating a face while rotating forward and a shield body having a water pressure chamber behind it, and By supplying water pressure slightly higher than the groundwater level to the water pressure chamber to stabilize the face while excavating, and by making the excavated earth into a high-density slurry and pumping it backwards inside the shield body, the shield is a mud water balance type shield. This enables stable excavation comparable to that of the construction method.

In addition, a cutter head that excavates the face while rotating is installed at the front of the shield body propelled by the shield jack, and a water pressure chamber separated by a partition wall is installed behind the cutter head. Along with supplying slightly higher water pressure.

The mud water balance type shield is equipped with a means for turning the earth and sand excavated by the cutter head into the hydraulic chamber into a highly concentrated slurry, and a means for compressing the soil and pumping it backwards inside the shield body. This method is used for the hydraulically balanced pumping earth removal shield construction method, which achieves the same or higher reliability without requiring equipment such as muddy water supply equipment, control means, and muddy water treatment equipment, which are a major loss in construction methods. It provides a shield tunneling machine.

(Example) An embodiment of the present invention will be described in detail with reference to the drawings.

Figure 1 shows a shield excavator used in the hydraulically balanced pumping earth removal method.The shield body 1 is divided into two parts, a front shield 111 and a rear shield 1b. and the rear shield 1d is flexible.

The shield body 1 is propelled by a shield jack 3, and a cutter head 5 rotated by a cutter head motor 4 is provided at the front of the front shield 1a.

``The two-part force shovel 5 has a large number of cutters 6 protruding from the front side, and these cutters 6 excavate a face 7, and the excavated earth and sand is sent to the cutter head 5 through an earth and sand intake port (not shown). After being taken into the water pressure chamber 16 between the partition walls 1c provided at the front of the front shield 1d, it is installed in the shield main body 1 by a screw conveyor 8 provided diagonally so that one end thereof passes through the partition wall 1c. The soil is discharged to a closed soil discharge device 9.

- The water pressure chamber 1d of a sealed structure divided by a partition wall 1c is formed in the front part of one of the male front shields, and the water pressure chamber 14 is formed in the water pressure chamber 1d. The tip is connected.

The water pipe 10 has two control valves V, CV connected in parallel along the way to control the amount of inflow into the water pressure chamber 1d, and behind these control valves and CV are a water pipe 101 and a return pipe 10. It branches into two roads, □.

And water pipe 10. is the starting shaft 11 as shown in Figure 2.
A water pump 1 is installed in a water tank 12 installed on the ground nearby.
The return pipe 10□ is connected to the water tank 12, and a control valve v2 is also provided in the middle of the return pipe 10□, and these control valves v,, V2 are as follows. It is now controlled by.

Next, to explain the hydraulic balance type forced earth removal shield construction method, Figure 3 shows the state in which the shield body 1 launched from the starting shaft 11 is excavating, and shows the groundwater level Pg and groundwater amount of the ground during excavation. changes. Therefore, in this construction method, the water pipe 10. ．． 10, the water pressure Pf higher than the groundwater level Pg is sent to the water pressure chamber 1d to stabilize the face 7, and the water pressure Pf to be sent is equal to the groundwater level Pg + (0
,2~0.8)kg/cn! The water pressure in the water pressure chamber 1d is controlled as follows so as to maintain the above value even if the groundwater level Pg fluctuates.

Water pressure detector 1 provided on the partition wall 1c of the front shield 1d
5 detects the water pressure in the water pressure chamber 1d and sends it to the water pressure setting device 17 via the converter 16. As shown in FIG. 4, the water pressure setting device 17 includes an actual water pressure indicator 173 that displays the actual water pressure based on the signal sent from the water pressure detector 15, a water pressure upper and lower limit setting section 17°, and a lower limit setting section 17. ．． By setting the upper and lower limits of the water pressure in the water pressure chamber 16 in advance using the upper and lower limit setting units 17b and 17e, the control valves V, V2 connected to the water pressure setting device 17 can be adjusted.
The opening/closing is controlled as follows. That is, when the water pressure Pf in the water pressure chamber 16 reaches the upper limit value, the control valve V2. Control valve V after a time preset by a timer has elapsed from the state where CV is open.

is closed, and after the time set by the timer, the water pump 13 is turned off.

Although the timer is not shown, it is provided in the control panel 20 connected to the water pressure setting device 17 and the water pump, respectively, to prevent the water pressure from changing rapidly.
In order to clean the inside of 0, a structure is adopted in which the time can be arbitrarily set according to the situation.

Further, when the water pressure Pf in the water pressure chamber 1d is between the upper limit value and the lower limit value, each control valve v2. CV, V+, and the water pump 13 are maintained, but when the lower limit is reached, the water pump 13 is first turned on to start water feeding, and then, after the time set by the timer has elapsed, the control valve v1 is opened and the water pressure chamber 1d is opened. After the time set by the timer has elapsed, the control valve V2. CV is closed (control valve CV may be open), and the water pressure in the water pressure chamber 1 rises to the set value.

In the figure, reference numeral 14 indicates a water supply pipe that supplies water to the water supply tank 12, and by turning on and off the solenoid valve 19 provided in the water supply pipe 14 according to a signal from a water level gauge 18 provided in the water supply tank 12, the water is constantly maintained at a constant level. The water level is maintained.

On the other hand, the earth and sand excavated by the force lid head 5 and taken into the water pressure chamber 1□ from the earth and sand intake port is mixed with the water in the water pressure chamber 16 and turned into a slurry, but at this time, the volume ratio is 50 to 9.
In order to accumulate the earth and sand in the water pressure chamber 1d so as to form a highly concentrated slurry of 0%, the shield jack 3 and the sealed earth removal device 9, which propel the shield body 1 in a primary manner, are controlled.

That is, the partition wall 1c of the front shield 18 has a hydraulic chamber 1d.
A concentration detector 21 is provided to detect the concentration of the slurry in the slurry, and a concentration signal detected by the concentration detector 21 is sent to a hydraulic pump 23, 24 via a converter 22. The hydraulic pump 23 supplies hydraulic pressure to the shield jack 3, and the hydraulic pump 24 supplies hydraulic pressure to the sealed soil removal device 9 to drive them. When the slurry concentration in the hydraulic chamber 14 reaches a preset upper limit, , the amount of oil supplied from the hydraulic pump 24 to the sealed earth removal device 9 is increased, the amount of soil removed by the sealed earth removal device 9 is increased, and the oil pressure supplied from the hydraulic pump 23 to the shield jack 3 is decreased. As a result, the propulsion speed of the shield body 1 decreases.

Note that it is not necessary to perform the above control at the same time; first increase the speed of the sealed soil discharge bag W9 to increase the volume of soil discharge, and if the slurry concentration does not decrease even after this, the propulsion speed of the shield jack 3 is decreased by timer control. You can do it like this. As a result, the amount of earth and sand in the hydraulic chamber 14 is reduced, so that the slurry concentration is reduced without exceeding the upper limit.

On the other hand, when the slurry concentration decreases to the lower limit value, the hydraulic pump 24 that supplies hydraulic pressure to the sealed earth removal device 9 is decelerated or stopped. At the same time, the speed of the hydraulic pump 23 that supplies hydraulic pressure to the shield jack 3 is increased to increase the propulsion speed, so more earth and sand are taken into the hydraulic chamber I4, and the slurry concentration increases.

In this case as well, first reduce the amount of soil removed by the sealed soil removal device,
If the slurry concentration does not increase even after this, the propulsion speed of the shield jack 3 may be controlled to be increased by timer control.

By controlling the slurry concentration in the water pressure chamber 14 as described above, the earth and sand taken into the water pressure chamber 14 becomes a highly concentrated slurry with a volume ratio of 50 to 90%, and is transferred to the water pressure chamber by the screw conveyor 8. 14 and is further consolidated while being conveyed by the screw conveyor to increase the slurry concentration. The soil is then discharged to a sealed soil removal device.

The sealed earth removal device 9 includes a cylinder 93 and this cylinder 9. The device has a piston (not shown) that pumps the earth and sand thrown into the container, and the highly concentrated slurry pumped from the sealed earth removal device 9 passes through the earth removal pipe 25 and is sent to the hopper 2 installed on the ground.
6 and then transported by a transport vehicle 27. Note that a transport vehicle 28 such as a trolley may be provided in the tunnel as shown in FIG. 6 to transport the earth and sand carried out from the discharge pipe 25.

In addition, in order to prevent the water injected into the water pressure chamber 1d from penetrating through the face 7 and escaping, bentonite is inserted between the face 7 and the heel 5 through an injection pipe 29 provided at the center of the cutter head 5. liquid or foaming agent.

A filler such as rice husk, sawdust, or fiber may be injected to reduce the water permeability of the face 7, or hentonite may be mixed with the water injected from the water pipe 10.

(Effects of the Invention) As detailed above, this invention supplies water set at a pressure higher than the groundwater pressure of the face to the front part of the shield body that excavates underground, thereby stabilizing the face while excavating the face. Compared to the conventional mud water balance shield construction method, which stabilizes the face by injecting mud water, the entire equipment is smaller and cheaper, and it is also easier to control because it only requires controlling the supply water pressure. be.

In addition, since the excavated earth and sand is maintained in a highly concentrated slurry state and carried out backwards inside the shield body using soil removal means such as a screw conveyor or a closed earth removal device, it is possible to There is no need for equipment such as a sewage treatment device.2 This makes it possible to perform construction in locations where there is no space to install a sewage treatment device near the starting shaft, and also allows construction over long distances.

Moreover, unlike earth pressure shields, the cutter head is not filled with earth and sand and rotated, so the cutter life can be greatly improved, and some of the high concentration slurry is absorbed by the shield itself and the ground. Because it passes through the gap and reaches the tail void formed behind the shield body, ground subsidence due to tail voids can be minimized, or the amount of backfill material injected to prevent ground subsidence can be significantly reduced. It is economical because it can be done.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a sectional view of the shield tunneling machine, Fig. 2 is a piping diagram of the water supply system, Fig. 3 is an explanatory diagram of the operation, and Fig. 4 is an explanatory diagram of the water pressure setting device. , Figures 5 and 6
The figure is an explanatory diagram of the action. 1... Shield body. 1....Hydraulic pressure room. 5... Cutter head. 9... Sealed earth removal device 9 13... Water pump. v,, V2. CV - control valve. Pg...groundwater level. Patent application Lawyer 1c...Partition wall. 3...Shield jack 8...Screw conveyor 10...Water pipe 21...Concentration detector. Osamu Matsuzawa, Komatsu Ltd. (patent attorney)

Claims (6)

[Claims] (1) Propel the cutter head 5 that excavates the face while rotating forward, and the shield body 1 having the water pressure chamber 1_d behind it, and supply water pressure slightly higher than the groundwater level Pg to the water pressure chamber 1_d to excavate the face. This method is characterized by excavating while stabilizing the earth and sand 7, and turning the excavated earth and sand into a high-density slurry, and then pumping and removing the earth backwards inside the shield body 1. (2) The water pressure Pf supplied to the water pressure room 1_d is set to the groundwater level Pg.
The hydraulic balance type pumping earth removal shield construction method according to claim 1, wherein the earth pressure is increased by 0.2 to 0.8 kg/cm^2. (3) A cutter head 5 that excavates the face 7 while rotating is provided in the front part of the shield body 1 propelled by the shield jack 3, and a water pressure chamber 1_d divided by a partition wall 1_c is provided behind the cutter head 5, and the water pressure chamber 1_d is separated by a partition wall 1_c. A means for supplying water pressure slightly higher than the groundwater level Pg by a water supply means, a means for turning the earth and sand excavated by the cutter head 5 and taken into the water pressure chamber 1_d into a highly concentrated slurry, and consolidating this to form a shield main body. 1. A hydraulically balanced type earth-feeding shield excavator equipped with a force-feeding earth-evacuation means for force-feeding earth backwards. (4) The water supply means includes a water pump 13 that supplies water in the water tank 12 to the water pressure chamber 1_d via the water pipe 10;
It is installed in the middle of the water pipe 10, and the water in the water pressure chamber 1_d is always 0.2 to 0.8 kg/cm lower than the groundwater level Pg.
^2 Control valves V_1, V_2, which are controlled to become high
4. The seeded excavator according to claim 3, comprising a CV. (5) The high concentration slurry forming means is connected to a concentration detector 21 that detects the slurry concentration in the water pressure chamber 1_d, and a shield jack 3 according to the concentration signal detected by the concentration detector 21.
2. The shield excavator according to claim 1, further comprising a control means for controlling the amount of propulsion of the earth excavator and the amount of earth and sand conveyed by the sealed earth removal device. (6) The above-mentioned force-feeding earth-unloading means includes a screw conveyor 8 that further increases the concentration of the high-concentration slurry taken in from the water pressure chamber 1_d, and a sealed earth-unloading device 9 that consolidates and pressurizes the earth and sand discharged from the screw conveyor 8. 4. The shield excavator according to claim 3, comprising: