JPS6224597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid pressurized shield tunnel excavation method, and more particularly to a method for excavating a tunnel while blocking the flow of groundwater in a face and preventing collapse and uplift of the ground at the face.

The mud water pressurized shield tunnel excavation method, which has traditionally been used as one of the shield tunnel excavation methods, excavates while applying mud water pressure to the face.
Excavated earth and sand are introduced into the mud chamber from the cutter slit section, and then transported from the mud chamber to the outside of the mine via a mud wheel pipe, and the speed of the excavation machine is controlled according to the amount of soil discharged to the outside of the mine. It was hot.

The amount of soil discharged is generally calculated by measuring the density of the ground, the specific gravity of the mud flowing in the mud wheel pipe, the flow rate of mud being transported and discharged, etc., and inputting these measured values into a computer etc. . In this way, methods have been used in which the speed of the excavator is automatically controlled or manually adjusted depending on the amount of earth removed by calculation. However, the density of the ground is calculated by conducting a soil survey in advance and then inputting an assumed value into the calculation formula, resulting in errors. Moreover, since errors in flow rate and specific gravity are added to this error, an extremely large error may occur in the overall numerical value of the amount of soil removed. These errors directly affect the digging speed,
An imbalance occurred between the amount of excavated soil and the speed, and as a result, complete stability of the face could not be guaranteed, causing ground subsidence and upheaval.

In addition, according to the conventional construction method, the mud pressure applied to the face was selected so that it counteracted both the earth pressure of the face and the groundwater pressure, so collapse of the face could be prevented. There is a problem that the flow of groundwater pressure cannot be prevented, and mud water pressure that can prevent the flow of groundwater cannot prevent the collapse of the face. In particular, mud water pressure is set based on prevention of face collapse. Groundwater flows often occur. The flow of groundwater causes problems such as intrusion of groundwater into the shield body, resulting in ground failure, ground subsidence, and other problems such as inflow into underground structures such as wells, and gushing.

Therefore, an object of the present invention is to prevent the flow of groundwater by applying a liquid to the groundwater, and to prevent subsidence and uplift of the ground by pressing a cut head on the face. The object of the present invention is to provide a method for excavating a tunnel while maintaining the natural state as it is and thereby maintaining complete stability of the face.

The liquid pressurized shield tunnel excavation method of the present invention prevents the flow of groundwater by applying liquid to the face at a pressure approximately equal to the groundwater pressure at the face during tunnel excavation, and also increases the propulsion speed of the shield body and the rotation of the cutter head. By controlling at least one of the speed, the amount of relative movement between the cutter head and the shield body, and the opening degree of the cutter slit, the cutter head is pressed against the face with a pressure that is greater than the active earth pressure of the face ground and smaller than the passive earth pressure. Prevents ground collapse and upheaval.

The features of the invention will become clearer from the following description of the illustrated embodiment.

In FIG. 1, a liquid pressurized shield tunneling apparatus for carrying out the method of the invention is shown schematically at 10. This liquid pressurized shield tunnel excavation device 10 includes a shield main body 12,
and a bulkhead 14 attached to the front of the shield body and across the shield body. Due to this partition wall 14, the inside of the shield body 12 has a water pressure chamber 1.
6 and an atmospheric pressure chamber 18. The partition wall 14
is provided with openings for the inlet and outlet of pressurized fluid, the openings being provided with pressurized fluid pipes 20 for supplying pressurized fluid, such as water or mud, into the hydraulic chamber 16 and for discharging it from the hydraulic chamber. A fluid pipe 22 is connected thereto.

A cutter head 24 is disposed within the water pressure chamber 16, and a drive shaft 2 fixed to the cutter head 24 is disposed within the water pressure chamber 16.
6 connects to the partition wall 1 through a bearing provided on the partition wall 14.
4 into a gearbox 28 attached to the rear of the vehicle. Inside this gearbox 28, a main gear 3 keyed to the drive shaft 26 is installed.
0 meshes with a gear 34 attached to a shaft extending into the box from a hydraulic drive motor 32 fixed to the outer wall of the gear box, whereby the drive shaft 26 is rotated by the driving force of the hydraulic drive motor 32 being transmitted.

The drive shaft 26 extends further through the bearing portion of the gearbox 28 and terminates in a housing 36 attached to the rear face of the gearbox 28. Inside the housing 36 is a load containing a load cell that is preset with a fixed or fixed range of earth pressure values between the active earth pressure and the passive earth pressure calculated based on the survey of the ground where the tunnel is to be dug. A detector or face pressure sensing device 38 is supported by rod 40. This load detector 38 is arranged against the end face of the drive shaft 26 . Attached to the rear surface of the housing 36 is a single-sided rod double-acting piston-cylinder device 42, the piston rod 44 of which communicates with passages formed within each of the rods 40, the load detector 38, and the drive shaft 26. through and extending to the forward end of the shaft.

Referring to FIG. 2, the cutter head 24 includes a face 46 secured to the end of the drive shaft 26 with cutter slits 48 spaced radially therefrom. Additionally, the cutter head 24 includes a cutter disk 50 located behind the face 46 and slidably disposed on the drive shaft 26. The cutter disk has a plurality of cutter bits 52 on the face 46.
It is attached at a position aligned with the cutter slit 48 of the cutter. As a result, Katsutabitsu 52
Sliding of the cutter disk 50 on the drive shaft 26 allows it to move in and out of the cutter slit 48 in the front and rear directions.

A plurality of rods 54 are attached to the cutter disk 50, as shown in FIG. ing. One end of each rod 54 is screwed and fixed to the cutter disk 50, and the other end is connected to the connecting member 5.
8. They are interconnected by 8. Fixed to this coupling member 58 is the end of a piston rod 44 which extends to the forward end of the drive shaft 26 through a passage 60 formed longitudinally in the center of the drive shaft 26.

As a result, the cutter disk 50 slides on the drive shaft 26 by the force transmitted by the piston rod 44, the connecting member 58, and the rod 54, powered by the single-rod double-acting piston-cylinder arrangement 42.

The shield body 12 is formed with a radially inwardly projecting flange 62, and a shield body propelling jack 66 is provided between the flange and a segment 64 for a tunnel assembled rearward along the inner surface of the shield body 12. The jack applies a reaction force to the end face of the segment 64 to propel the shield body 12.

A hydraulic drive motor 32 for rotating the drive shaft 26, a piston cylinder device 42 for sliding the cutter disk 50 to adjust the amount of protrusion of the cutter bit 52 from the slit 48, that is, the opening degree of the cutter slit, and a shield main body propulsion jack 66.
Each of the variable hydraulic supply amount pumps 68, 70, 7
Connected to 2. These variable pumps are operated by a hydraulic power unit 74. The variable pumps 68, 70, 72 each include control arms 76, 78, 80 for controlling the amount of hydraulic pressure supplied. These control arms 76, 78, 8
0 end is each one side rod type double acting piston.
The control arm is pivotally connected to the piston rods of the cylinder units 82, 84, and 86, and the movement of the piston rods causes the control arm to swing, thereby controlling the amount of hydraulic pressure supplied to the variable pump.

These piston/cylinder devices 82, 84,
86 is a force feedback type servo valve 88,9
It is connected to a pump 94 via 0 and 92.
These servo valves 88, 90, and 92 are well known, and therefore, detailed explanation of their construction will be omitted.
The differential voltage transformer of each servo valve 88, 90, 92 is connected to an electrical control device 96 by an electrical line for controlling the servo valve using electrical signals. This electrical control device 96 includes a load detector 38
It is connected to the load detector by an electrical line in order to also receive electrical signals from the load detector.

According to the liquid pressurized shield tunnel excavation device 10 described above, during tunnel excavation, muddy water (or fresh water) is supplied from the pressurized fluid pipe 20 into the water pressure chamber 16 and is discharged through the fluid pipe 22. The pressure of the muddy water from the fluid pipe 20 is such that the pressure of the muddy water in the water pressure chamber 16 is kept at the face 1 so as not to cause the flow of groundwater.
The pressure is selected to be approximately equal to the groundwater pressure at 0.00.

The cutter head 24 is rotated by a driving force from a hydraulic drive motor 32 being transmitted to a gear 34, a reduction gear 30 meshing with the gear, and a drive shaft 26. Next, the shield body 12 is propelled by the shield body propulsion jack 66, and thereby,
The cut head is pressed against the ground face with a pressure greater than its active earth pressure and less than its passive earth pressure, and excavates without impairing the stability of the ground face.

In this way, in the liquid pressurized shield tunnel excavation device 10, the liquid pressurized almost equal to the pressure of groundwater at the face counteracts the underground water, and the liquid pressurized against the ground at the face does not impair the stability of the ground. Counteracting with the cut head pressed against this by pressure,
Excavate while preventing the flow of groundwater and the collapse and uplift of the ground.

In this way, during excavation of the face ground, the pressing force of the cutter head against the face ground is applied to the cutter head as a reaction force from the face ground, and this reaction force, which is the earth pressure received by the cutter head, is transmitted via the drive shaft 26 to a horizontal thrust load. as load detector 38
detected. That is, the load detector 38 determines whether or not the cutter head is pressing against the face ground with a pressure greater than its active earth pressure and less than its passive earth pressure, that is, the face which is the reaction force of the face ground against the cutter head Earth pressure was set in the load detector 38 in advance. It detects whether the earth pressure is greater than the active earth pressure and less than the passive earth pressure (generally, the passive earth pressure is two to several tens of times the active earth pressure), or whether it is greater or less than the set earth pressure.

For example, when the pressing force of the cutter head becomes smaller than the set earth pressure, the electric control device 96 that receives a signal from the load detector 38 senses this condition and sends a signal to one of the servo valves 88, 90, and 92. give. For example, when a signal is applied to the servo valve 88, the piston/cylinder device 82 is actuated to swing the control arm 76 and control the driving force of the hydraulic drive motor 32 to slow the rotation of the cutter head 24. As a result, the amount of excavated soil is reduced, and since the propulsion speed of the shield body is constant, the pressing force of the cutter head increases and counteracts the face ground with higher earth pressure.

Further, when the servo valve 90 is controlled, the control arm 78 is similarly swung to control the propulsive force of the shield main body propulsion jack 66, increasing its propulsion speed and increasing the pressing force of the cutter head against the face ground. It will be done. Furthermore, when the servo valve 92 is controlled, the operation of the piston and cylinder arrangement 42 is controlled, causing the piston rod 44 to move to the right in FIG. is moved to the right in Figure 2. As a result, the cutter bit 52 attached to the cutter disk 50 is retracted from the slit 48 of the face 46, as shown in FIG. .

On the other hand, if the pressing force of the cutter head 24 against the ground becomes greater than the passive earth pressure, in other words, if the face earth pressure becomes greater than the passive earth pressure relative to the pressing force of the cutter head,
The electric control device 96 senses the state via the load detector 38 and controls one of the servo valves to control the rotation of the cutter head, the propulsion force of the shield body, or the opening degree of the cutter slit in the case described above. is adjusted to the opposite state.

In this way, the rotational speed of the cutter head, the propulsion speed of the shield body, the cutter slit, or the cutter head described later, depending on whether the face earth pressure (that is, the cutter pressing force) is higher or lower than the preset face earth pressure. By controlling one of the opening degrees of the amount of movement relative to the shield body,
By changing the amount of excavated soil, it is possible to press the cutter head against the ground face with a pressure that is always greater than its active earth pressure and less than its passive earth pressure, and as a result, it is possible to prevent collapse and upheaval of the face ground. Can dig tunnels.

A liquid pressurized shield tunneling apparatus 110 for carrying out the method of the present invention shown in FIG.
The interior of the shield body 12 is divided into a water pressure chamber 16 and an atmospheric pressure chamber 18 by the partition wall. This device 110 is also the device 11 shown in FIG.
Similarly, there are a supply pressurized fluid pipe 20 and a discharge fluid pipe 22 attached to the bulkhead 14, a cutter head 24 disposed within the hydraulic chamber 16, and a cutter head 24 fixed to the cutter head and attached to the rear surface of the bulkhead. Drive shaft 2 extending into gearbox 28
6. Drive shaft 2 in gear box 28
6, and a gear 34 that meshes with the main gear 30 and is fixed to a shaft that extends into the gearbox from a hydraulic drive motor 32 that is fixed to the outer wall of the gearbox.

The drive shaft 26 in the device 110 has a fourth
The bulkhead 14 is rotatably and linearly movable as shown in the figure.
is supported by. This drive shaft 26 has a cylinder 112 fixed to the rear of the gearbox 28.
the drive shaft 2 inside the cylinder;
6 is provided with a flange portion 114 that serves as a piston. A rear cylinder chamber 116 within the cylinder defined by this flange or piston portion 114 is communicated with a hydraulic servo device 120 by a hydraulic conduit 118 .
As a result, the cutter head 24 is attached to the cylinder 1.
The cylinder face 100 is pressed against the face ground 100 by supplying hydraulic pressure to the twelve cylinder chambers 116 .

At the terminal end of the drive shaft 26 extending further rearward from the cylinder 112, a piston-cylinder arrangement 42 similar to that in the apparatus 10 shown in FIG. It extends in the direction of the cutter head 24 within a passage formed within the shaft 26 . The relationship between the cutter head 24 and the piston rod 44 is the same as that shown in FIG.

A further piston-cylinder arrangement 122 is arranged behind the piston-cylinder arrangement 42 and is fixed to the shield body 12 . The end of the piston rod 124 through which this piston/cylinder device extends is fixed to the cylinder portion of the piston/cylinder device 42 for adjusting the opening of the cutter slit. This occurs because the cutter head 24 in the device 110 is configured to be able to move in the axial direction independently of the propulsion of the shield body 12.
2, that is, the slide amount a. Therefore, the piston-cylinder device 122 is a sliding amount detector. The cylinder chamber of this slide amount detector 122 is also connected to the hydraulic servo device 120 through a hydraulic pressure conduit 126.

Hydraulic drive motor 32 of device 110, piston
The cylinder device 42 and the shield main body propulsion jack 66 are operated by operating valves 128, 130, 1, respectively.
32 to each variable pump 140, 142, 144 by conduits 134, 136, 138. These variable pumps are connected to a hydraulic servo device 120, and the amount of change is controlled by a hydraulic signal from the hydraulic servo device.

In this way, the device 110 can be used with the cutter head 24.
Since the cutter head 24 is completely separated from the shield body 12, counter-earth pressure can be generated in the cutter head 24 regardless of the propulsion of the shield body. Therefore, a set load is always applied in the cylinder chamber 116 of the piston-cylinder device 112, that is, a load such that the cutter head 24 presses the face ground 100 with a pressure greater than its active earth pressure and less than its passive earth pressure. It is only necessary to control so that the propulsion speed of the shield body 12 and the excavation speed of the cutter head 24 are synchronized.

This method of control is performed in a manner similar to that described with respect to the apparatus 10 shown in FIG. In other words, the rotational speed of the cutter head varies depending on the relative sliding amount between the cutter head and the shield body.
By controlling any one of the opening degree of the cutter slit, the propulsion speed of the shield body, or the relative sliding amount itself, the cutter head 24 is always kept in a predetermined positional relationship with respect to the shield body, that is, the cutter head is kept in a pressing force as described above. so that it is in a position relative to the shield body when pressing the face ground. However, if the face ground 100 is gravel, it is necessary to specify the opening degree of the cutter slit, and the excavation speed tends to be irregular when starting or stopping the device 110, so this also applies. Must be specified. In such a case, the amount of excavated soil is changed by controlling only the rotational speed of the cutting head.

In this manner, the device 110 does not directly control the counterpressure of the cutter head as in the device shown in FIG. 1, but indirectly controls it from the relative sliding amount of the cutter head and the shield body. The cutter head can be pressed against the face ground with very stable pressure.

The sliding amount can also be controlled by directly determining the difference between the propulsion speed of the shield body and the excavation speed of the cutter head. Such a device is shown in FIG.

A liquid pressurized shield tunnel excavation device 150 shown in FIG. 5 has a bracket 152 attached to the terminal end of a drive shaft 26 extending from a piston/cylinder device 112 for pressurizing a cutter head so as to allow rotation of the shaft. have A hydraulic drive motor 32 for providing drive power to the drive shaft 26 has a speed change lever 154 for controlling the speed of the motor, the upper end of which lever and a bracket 152 being connected to a rod 1 parallel to the drive shaft 26.
56.

As a result, if the amount of excavated soil increases and the cutter head 24 moves forward faster than the propulsion speed of the shield body 12 and relatively slides by a, the drive shaft 26 moves to the left as seen in FIG.
A shift lever 154 is swung by a rod 156 to slow the rotation of the hydraulic drive motor 32. However, since the shield body 12 is always propelled at a constant speed, the sliding amount a gradually returns to its original state, and at the same time, the rotation of the hydraulic drive motor 32 is also accelerated.

Shield tunnel excavation device 1 shown in Figure 6
Reference numeral 60 automatically controls the opening degree of the cutter slit based on the relative sliding amount between the shield body 12 and the cutter head 24. That is, a downwardly extending bracket 162 is attached to the terminal end of the drive shaft 26 extending from the piston/cylinder device 112 for pressurizing the cutter head to permit rotation of the drive shaft.
A link member 164 is attached to the shield body 12, and the other end of the link member is pivotally connected to the end of a rod 166 that is pivotally connected to the bracket 162 and parallel to the drive shaft 26. There is. The end of a rod 44 extending through the internal passage of the drive shaft 26 for adjusting the opening degree of the cutter slit is pivotally connected to a link member 164.

According to this configuration, a preset pressure is applied to the piston/cylinder device 122 in order to press the cutter head 24 against the face ground 100 with a preset pressure that is greater than its active earth pressure and smaller than its passive earth pressure, During excavation, when the amount of excavated soil in the face ground 100 increases and the cutter head advances faster than the shield body and slides relative to the shield body 12, the drive shaft 26 moves to the left as seen in FIG. At the same time, the link member 164 is swung. As a result, the rod 44 is pushed in by an amount proportional to the amount of movement or slide amount a of the drive shaft 26, but is pulled out rearwardly from the shaft relative to the movement of the drive shaft. As a result, as explained in Figures 2 and 3,
Katsutabitsu 5 from slit 48 of face 46
2 is pulled in and the slit opening becomes smaller. This reduces the amount of soil excavated in the face ground 100 by the cutter head, slows down the excavation speed, and restores the position relative to the shield body to a predetermined state.

As described above, according to the liquid pressurized shield tunnel excavation method of the present invention, the cut head is pressed against the face ground with a pressure greater than its active earth pressure and less than its passive earth pressure, thereby preventing collapse and uplift of the face ground. Since the flow of groundwater is blocked by supplying mud or fresh water with a pressure almost equal to the groundwater pressure at the face ground into the hydraulic chamber, the ground and groundwater are maintained in their natural state, that is, the face ground is completely drained. Tunnels can be excavated under stable conditions.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing a liquid pressurized shield tunnel excavation device implementing the method of the present invention;
Figure 2 is a sectional view showing the structure of the cutter head, Figure 3
The figure is a cross-sectional view taken along line 2-2 in Figure 2, and Figures 4, 5, and 6 are cross-sectional views schematically showing other liquid pressurized shield tunnel excavation equipment implementing the method of the present invention, respectively. It is. 10, 110, 150, 160: Liquid pressurized shield tunnel excavation device, 12: Shield main body,
14: bulkhead, 24: cutter head, 26: drive shaft, 32: hydraulic drive motor, 38: face earth pressure detector, 48: cutter slit, 52: cutter bit, 66: shield main propulsion jack, 96:
Electrical control device, 100: Face ground.

Claims (1)

[Scope of Claims] 1. A liquid pressurized tunnel excavation method, which prevents the flow of groundwater by applying a liquid to the face at a pressure approximately equal to the groundwater pressure at the face during tunnel excavation, and also promotes the shield body. By controlling at least one of the following: speed, rotational speed of the cutter head, relative movement between the cutter head and the shield body, and opening degree of the cutter slit, the cutter head is moved to the face with a pressure greater than the active earth pressure of the face ground and less than the passive earth pressure. A liquid pressurized tunnel excavation method characterized by preventing collapse and uplift of the face ground by applying pressure. 2. The liquid pressurized tunnel excavation method according to claim 1, wherein fresh water is applied to the face ground. 3. The liquid pressurized tunnel excavation method according to claim 1, wherein muddy water is applied to the face ground.