JPH07116909B2 - Water pressure balance type pumping and discharging shield method and shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a hydraulic balance type pressure-feeding and discharging method in which a face is excavated while stabilizing the face by water pressure, and the excavated earth and sand is made into a high-concentration slurry and pressure-fed backwards. The present invention relates to a soil shield construction method and a shield machine used in the construction method.

(Prior Art) Conventionally, as a shield construction method for excavating a tunnel with a shield machine, a muddy water shield method and an earth pressure shield method are known.

In the former muddy water balance type shield construction method, pressurized muddy water is injected between the cutter head and face during excavation to excavate while stabilizing the face, and the excavated earth and sand is slurried and pumped backwards to be discharged. It has become.

In the latter earth pressure shield method, the excavation excavated by the cutter head is filled into the cutter head to prevent excessive sediment from flowing into the cutter head, thereby stabilizing the face and excavating. At the same time, the excavated earth and sand is carried out backward by a earth and sand transport device such as a screw conveyor.

(Problems to be solved by the invention) However, while the muddy water balance type shield construction method has excellent workability and durability such as a shield excavator, it is a mud pipe for feeding muddy water, and a sludge discharger for carrying out sediment along with muddy water. The system is expensive because it requires a pipe and a pump facility for sending and discharging mud, and a muddy water treatment facility that solidifies the discharged muddy water on the ground, and also installs a muddy water treatment facility on the ground near the transmission shaft. Since it requires a space to do so, it is difficult to construct in a place where space cannot be secured.

In addition, the earth pressure shield method is less expensive than the muddy water balance type shield method, but the workability is poor due to difficulty in stabilizing the cutting face, and the cutter head is filled with earth and sand. Since the cutter is rotated to advance, the life of the cutter is short and it is not suitable for long-distance construction.

The present invention has been made for the purpose of improving the above-mentioned problems, and has the same stable workability as the muddy water balance type shield construction method, and is used for the water pressure balance type pressure and discharge shield construction method and the construction method capable of long-distance construction. It is intended to provide a shield machine that does.

(Means and Actions for Solving the Problem) In order to achieve the above-mentioned object, the present invention promotes a sulcutta head for excavating a face and a shield body having a water pressure chamber behind the face while rotating forward. By supplying a slightly higher water pressure than the groundwater level to the above water pressure chamber to excavate while stabilizing the cutting face, the excavated earth and sand is made into a high density slurry and pressure-fed inside the shield body, so that a mud balance type Enables stable excavation similar to the shield method.

In addition, a cutter head for excavating a face while rotating is provided in the front part of the shield body propelled by the shield jack, and a water pressure chamber divided by a partition wall is provided behind the cutter head. In addition to supplying high water pressure, a means for making a high concentration slurry of earth and sand excavated by the cutter head and taken into the water pressure chamber, and a pressure feeding and discharging means for consolidating this and sending it backward in the shield body were provided. As a result, it is possible to obtain equivalent or higher reliability without the need for large-scale muddy water supply devices, control means, and muddy water treatment devices such as the muddy water balance type shield construction method. The shield method and the shield machine used in the method are provided.

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

The first figure shows a shield machine for use in hydraulic balance equation pumping dumping method, the front shield 1 _a and the rear shield
2 split shield body 1 to 1 _b, during the front shield 1 _a and the rear shield 1 _b is freely bent by articulated jack 2.

Further the shield body 1 while being propelled by the shield jacks 3, the cutter head 5 in front of the front shield 1 _a is rotated by the cutter head motor 4 is provided.

A large number of cutters 6 are provided on the front surface of the cutter head, and the cutters 6 are used to excavate the face 7,
The excavated earth and sand is taken into the hydraulic head chamber 1 _d between the cutter head 5 and the partition wall 1 _c provided at the front part of the front shield 1 _a from the earth and sand intake (not shown), and then one end side the screw conveyor 8 provided obliquely so as to penetrate the partition wall 1 _c, and is discharged into the enclosed soil discharge device 9 installed in the shield body 1.

Meanwhile the front portion of the front shield 1 _a, the pressure chamber 1 _d of the sectioning has been sealed structure be formed by a partition wall 1 _c, the water pressure chamber 1 _d is being formed, the water pressure chamber 1 _d The tip of the water pipe 10 is connected to.

The water pipe 10 controls the amount of inflow into the hydraulic chamber 1 _d on the way 2
The individual control valves V ₁ and CV are connected in parallel, and the rear of these control valves V ₁ and CV is branched into two paths of a water supply pipe 10 ₁ and a return pipe 10 ₂ .

As shown in FIG. 2, the water supply pipe 10 ₁ is connected to a water supply tank 12 installed on the ground near the starting shaft 11 via a water supply pump 13, and the return pipe 10 ₂ is connected to the water supply tank 12. , the control valve V ₂ in the middle of the return pipe 10 ₂ is provided, these control valves V _1, V ₂ is adapted to be controlled as follows.

Next, the water pressure balance type pumping and discharging shield construction method will be explained. Fig. 3 shows the state in which the shield body 1 started from the starting shaft 11 is being excavated. The groundwater level Pg and the amount of groundwater in the excavated ground are shown. Fluctuates. Therefore, in this construction method, the water pressure Pf higher than the groundwater level Pg is sent to the water pressure chamber 1 _d from the water tank 12 installed above the groundwater level Pg to the water pressure chamber 1 _d via the water pipes 10 ₁ and 10 to stabilize the face 7. Therefore, the water pressure Pf to be sent is the groundwater level Pg + (0.2 to 0.8) kg / cm ²
The water pressure in the water pressure chamber 1 _d is controlled as follows so that the above value is maintained even if Pg changes.

The water pressure detector 15 provided on the partition wall 1 _c of the front shield 1 _a detects the water pressure in the water pressure chamber 1 _d and sends it to the water pressure setting device 17 via the converter 16. The water pressure setting device 17 is, as shown in FIG.
And the actual water pressure indicator needle 17 _a to display the actual pressure according to a signal sent from the pressure detector 15, the upper limit of the water pressure and the lower limit setting unit 17 _b
And a lower limit setting unit 17 _c are provided respectively, and the upper and lower limits of the water pressure in the water pressure chamber 1 _d are set in advance to the upper and lower limit setting units 17 _b and 17 _{c, respectively.}
The control valves V ₁ and V ₂ connected to the water pressure setting device 17 are controlled to be opened and closed as follows by setting in. That is, when the water pressure Pf in the water pressure chamber 1 _d reaches the upper limit value, the control valve V ₁ is closed after the time set in advance by the timer from the state where the control valves V ₂ , CV are opened, and the water pump after the time set by the timer 13 is off.

Although not shown, the timer is provided on the control panel 20 connected to the water pressure setting unit 17 and the water pump, respectively, to prevent a sudden change in water pressure and to clean the inside of the water pipe 10. It has a structure in which the time can be set arbitrarily according to the situation.

Further, while the water pressure Pf in the water pressure chamber 1 _d is between the upper limit value and the lower limit value, the control valves V ₂ , CV, V ₁ and the water feed pump 13 are maintained in the above states, but when the water pressure Pf becomes the lower limit value, first the water feed pump 13 is turned on to start water supply, and after the time set by the timer elapses, the control valve V ₁ opens and injection into the hydraulic chamber 1 _d is started, and control is performed after the time set by the timer elapses. The valves V ₂ and CV are closed (the control valve CV may be open), and the water pressure in the water pressure chamber 1 _d rises to the set value.

In the figure, 14 is a water supply pipe for supplying water to the water supply tank 12, and the water supply pipe is supplied by a signal from a water level gauge 18 provided in the water supply tank 12.
A constant water level is always maintained by turning on and off the solenoid valve 19 provided on the valve 14.

On the other hand, the earth and sand excavated by the cutter head 5 and taken into the hydraulic chamber 1 _d from the earth and sand intake port are mixed with the water in the hydraulic chamber 1 _d to form a slurry. At this time, the volume ratio is 50-90. In order to retain the earth and sand in the water pressure chamber 1 _d so that the slurry becomes a high concentration slurry of 10%, the shield jack 3 for propelling the shield body 1 and the closed earth removing device 9 are controlled as follows.

That is, the partition wall 1 _c of the front shield 1 _a is provided with a concentration detector 21 for detecting the concentration of the slurry in the water pressure chamber 1 _d , and the concentration signal detected by this concentration detector 21 is converted by the converter 22. Is sent to the hydraulic pumps 23, 24 via. Hydraulic pump 23 goes to shield jack 3 and hydraulic pump 24
Supplies hydraulic pressure to the closed earth removing device 9 to drive them, and when the slurry concentration in the water pressure chamber 1 _d reaches a preset upper limit value, it is supplied from the hydraulic pump 24 to the closed earth removing device 9. The amount of oil to be supplied is increased, the amount of earth discharged from the closed earth discharging device 9 is increased, and the hydraulic pressure supplied from the hydraulic pump 23 to the shield jack 3 is decreased, so that the propulsion speed of the shield body 1 is decreased.

Note that it is not necessary to perform the above-mentioned control at the same time. First, the speed of the closed soil discharging device 9 is increased to increase the amount of soil discharged, and if the slurry concentration still does not decrease, the propulsion speed of the shield jack 3 is decreased by timer control. You may do it. As a result, the amount of sediment in the hydraulic chamber 1 _d decreases, so the slurry concentration decreases 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 closed soil discharging device 9 is decelerated or stopped. At the same time, since the hydraulic pump 23 that supplies hydraulic pressure to the shield jack 3 is accelerated and the propulsion speed is increased, a large amount of earth and sand is taken into the water pressure chamber 1 _d , and the slurry concentration increases.

Also in this case, first, reduce the amount of soil discharged from the closed soil discharging device,
If the slurry concentration still does not increase, the propulsion speed of the shield jack 3 may be increased by timer control.

By controlling the concentration of the slurry water pressure chamber 1 _d as described above, sediment was incorporated into the water pressure chamber 1 _d is a volume ratio
A high-concentration slurry of 50 to 90% is discharged from the hydraulic chamber 1 _d by the screw cobener 8 and is further consolidated while being conveyed by the screw conveyor to increase the slurry concentration and then the screw conveyor 8 It is discharged to the closed soil discharging device through the soil discharging port 8a provided at the end.

The closed soil discharging device 9 has a cylinder 9a and a piston (not shown) for pumping the earth and sand put into the cylinder 9a, and the high-concentration slurry pumped by the closed soil discharging device 9 is a drain pipe. After being transported to a hopper 26 installed on the ground via 25, it is transported and processed by a transportation vehicle 27. In the tunnel, as shown in Fig. 6, transport vehicles such as trucks 28
May be provided to carry the earth and sand carried out from the discharge pipe 25.

In order to prevent the water injected into the water pressure chamber 1 _d from penetrating through the face 7 and leaking, the injection pipe 29 provided at the center of the cutter head 5 is provided between the face 7 and the cutter head 5 for bentonite station. Or a foaming agent, chaff, sawdust, fibers, etc. are injected to reduce the water permeability of the face 7, and the water pipe 10
Bentonite may be mixed with the water to be injected.

(Effect of the invention) As described in detail above, the present invention excavates a face while stabilizing the face by supplying water set to a pressure higher than the groundwater pressure of the face to the front part of the shield body that is excavating in the ground. Compared to the conventional muddy water balance type shield construction method that injects muddy water to stabilize the face, the entire equipment is smaller and less expensive, and it is only necessary to control the supply water pressure, so control is easy. is there.

Moreover, since the excavated earth and sand was kept in a high-concentration slurry state and was discharged to the rear inside the shield body by an earth discharging means such as a screw conveyor and a closed earth discharging device, it is possible to use the same method as in the above-mentioned muddy water shield method. This does not require maintenance of sewage treatment equipment, etc., which enables construction in places where there is no space to install sewage treatment near the starting shaft, and also construction over long distances.

Moreover, unlike the earth and sand shield, the cutter head is not rotated by filling the earth with sand and sand, so the cutter life can be significantly improved, and a part of the high-concentration slurry can be removed from the shield body and the ground. Since the tail voids formed behind the shield body are also reached through the gap, ground subsidence due to the tail voids can be minimized, or the amount of backfill material injected to prevent ground subsidence can be greatly reduced. Therefore, it is economical.

[Brief description of drawings]

The drawing shows one embodiment of the present invention. Fig. 1 is a cross-sectional view of a shield machine, Fig. 2 is a piping diagram of a water supply system, Fig. 3 is an operation explanatory diagram, and Fig. 4 is an explanatory diagram of a water pressure setting device. , Figures 5 and 6
The figure is a diagram for explaining the operation. 1 ... Shield body, 1 _c ...... Partition wall, 1 _d ...... Water pressure chamber, 3 …… Shield jack, 5 …… Cutter head, 8 …… Screw conveyor, 9 …… Closed earthing device, 10 …… Water pipe , 13 ...... water pump, 21 ...... concentration detector, V _1, V _2, CV ...... control valve, Pg ...... groundwater level.

Claims (6)

[Claims] 1. A shield body 1 having a cutter head 5 for excavating a face while rotating forward and a hydraulic chamber 1d behind it.
And excavate while stabilizing the face 7 by supplying a water pressure slightly higher than the groundwater level Pg to the water pressure chamber 1d, and excavating the excavated earth and sand into a high-density slurry to pressure-fed backward in the shield body 1. A hydraulic balance type pressure-feeding and discharging method characterized by soiling. 2. The water pressure balance type pressure-feeding and discharging shield construction method according to claim 1, wherein the water pressure Pf supplied to the water pressure chamber 1d is higher than the groundwater level Pg by 0.2 to 0.8 kg / cm ² . 3. A cutter head 5 for excavating a cutting face 7 while rotating at a front portion of a shield body 1 which is propelled by a shield jack 3, and a water pressure chamber 1d divided by a partition wall 1c behind the cutter head 5, and the water pressure chamber 1d is provided. To the groundwater level
Cutter head 5 while supplying a slightly higher water pressure than Pg
A hydraulic balance type pressure-feeding shield digging that is provided with means for making a high-concentration slurry of earth and sand that has been excavated by Machine. 4. A water supply pump 13 for supplying water in a water supply tank 12 to a water pressure chamber 1d via a water supply pipe 10, and water in the water pressure chamber 1d provided in the middle of the water supply pipe 10. 4. The shield machine according to claim 3, further comprising control valves V ₁ , V ₂ and CV which are controlled so as to be always higher than the groundwater level Pg by 0.2 to 0.8 kg / cm ² . 5. The high-concentration slurry forming means is equipped with a water pressure chamber 1d.
And a control means for controlling the propulsion amount of the shield jack 3 and the sediment transfer amount of the closed soil discharging device 9 according to the concentration signal detected by the concentration detector 21. The shield machine according to claim 3, wherein 6. A screw conveyor 8 for further increasing the concentration of a high-concentration slurry taken in from a hydraulic chamber 1d, and a closed earth-discharging device for consolidating and discharging the earth and sand discharged from the screw conveyor 8 by the pressure-feeding and discharging means. The shield machine according to claim 3, which is constituted by 9 and.