JPH0334560B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a shield propulsion method, and more particularly to a shield propulsion method suitable for use in a pipe propulsion method.

(Prior art) In the pipe propulsion method, a shield is generally installed at the forefront of the pipe to be propelled, and the ground is perforated by the operation of a cutter provided on the shield, followed by the operation of a jack at the rear of the pipe. exerts a thrust on the shield and tube, propelling them both into the drilled ground. The cutter is spaced in front of a bulkhead across the interior of the shield, and when the shield and tube are being propelled;
The material to be excavated that has been scraped off by the cutter is maintained in a state in which the space is filled with the space, and the material to be excavated causes earth pressure generated by the reaction force from the partition wall to act on the face of the ground. This earth pressure and the earth pressure of the ground are balanced and the face is maintained stably.

(Problem to be Solved by the Invention) Conventionally, the excavated material rotates within the above-mentioned interval as the cutter rotates, and reaches a discharge means such as a screw conveyor provided at the bottom of the partition wall, and is discharged through this discharge means. has been done. Therefore, a large frictional force acts between the excavated object and the partition wall, increasing the load on the cutter drive device. This tendency is particularly noticeable in sandy gravel ground, so when using the mud pressure method to advance sandy gravel ground, it is necessary to increase the concentration of bentonite in the muddy water supplied to the face or increase the amount of mud. This reduces friction. However, it is difficult to dispose of the muddy water after use, and the frictional force cannot be reduced with any method other than the muddy water pressurization method.

By the way, since the frictional force increases in proportion to the earth pressure of the ground, in order to reduce the frictional force, it is necessary to lower the earth pressure of the excavated object as much as possible. but,
Since it is not possible to lower the earth pressure below the active earth pressure, which is the limit of soil pressure in the ground, there is a natural limit to how much frictional force can be reduced even with the mud pressure method.

On the other hand, the friction force acting between the shield, the pipe following it, and the ground, which is different from the friction force of the object to be excavated, requires an extremely large thrust force for the jack.

Therefore, the object of the present invention is to reduce the frictional force generated by rotating the excavated material with the cutter within the space between the bulkhead and the cutter, or the frictional force acting between the shield and the pipe and the ground. The aim is to reduce the

Another object of the present invention is to provide a propulsion method that can be applied to a wide range of ground ranging from soft ground to hard ground.

Still another object of the present invention is to provide a propulsion method that can synchronize with changes in soil pressure in the ground.

(Means for Solving the Problems) A shield propulsion method according to the present invention causes a consolidation head to rotate eccentrically in front of a partition wall provided in the diametrical direction of a shield body, and rotates on its own axis, during which a thrust force is applied to the shield body. the shield body is propelled into the ground, and the axial force acting on the consolidation head from the ground or its excavated material is detected.

When this detected value exceeds a predetermined value, the propulsion speed of the shield body is reduced or the eccentric rotation speed of the consolidation head is increased. In another method, when the detected value exceeds a predetermined value, the propulsion speed of the shield body is decreased and at the same time the eccentric rotational movement speed of the consolidation head is increased.

(Embodiment) As shown in FIG. 1, the method of the present invention involves rotating the consolidation head 14 provided in the front space 12 of the shield body 10 eccentrically and rotating it on its own axis, and during the eccentric rotation of the consolidation head. The shield body 1
exerts thrust on 0. Then, the axial force acting on the consolidation head 14 is detected.

The consolidation head 14 is located offset from the center of the shield body 10 by an amount e, and rotates eccentrically with respect to the shield body 10, and simultaneously rotates on its axis. When the consolidation head 14 makes eccentric rotational movement within the space 12 of the shield body 10, the excavated material 16 is sandwiched between the shield body 10 and the consolidation head 14 and consolidated. Further, when the consolidation head 14 rotates, the consolidation head 14 rolls against the excavated object when consolidating the excavated object, so that the frictional force is significantly reduced.

In order to obtain a compaction effect on the excavated material, a conical or truncated conical space is provided in the space in front of the shield body, and the diameter gradually decreases toward the rear. Alternatively, a consolidation head having a circular cross-sectional shape is eccentrically rotated.
Another method of obtaining a consolidation effect on the excavated material is to form the space in front of the shield body into a cylindrical shape with substantially the same diameter in the axial direction of the shield body, and to form a conical or The truncated conical consolidation head is eccentrically rotated.

The part of the excavated material 16 to be consolidated is the consolidation head 1
4 sequentially moves in the circumferential direction of the shield body 10. On the other hand, the shield body 10
is moving forward by receiving thrust, so the excavated object 16
Earth pressure is generated, and this earth pressure acts on the face 19 of the ground 18 as shown by arrow A, countering the earth pressure of the ground and preventing the ground from collapsing. Earth pressure reaction force B
As the part of the excavated object to be consolidated moves sequentially in the circumferential direction, the excavated object 16 is sequentially pushed backward, and the consolidation head 14 and the shield body 1
0 and is discharged into the shear chamber 22 through the gap 20. The excavated object 16 is then transported outside the mine.

The amount of excavated material 16 discharged into the shear chamber 22 increases as the eccentric rotational speed N of the consolidation head 14 increases. Further, this discharge amount increases as the earth pressure P generated in the excavated object 16 increases. Therefore, the relational expression V=NPα holds between the propulsion speed V of the shield body 10, the eccentric rotational speed N of the consolidation head 14, and the earth pressure P. Here, α is a coefficient determined by the type of ground, particle size, and other properties. Rewriting this equation, it becomes P=V/Nα.

P in the above equation is obtained by dividing the axial force acting on the consolidation head 14 by the effective cross-sectional area of the consolidation head 14. This axial force varies because the coefficient α always varies depending on the ground. Therefore, the axial force acting on the consolidation head 14 is detected, and the shield propulsion speed V is increased until the detected value reaches a predetermined value, or the eccentric rotational movement speed N of the consolidation head 14 is increased.
When the detected value exceeds a predetermined value, the shield propulsion speed V is lowered or the consolidation head 14
The earth pressure can be kept constant by increasing the eccentric rotational movement speed N.

If the coefficient α fluctuates significantly, increase the shield propulsion speed V until the detected value reaches a predetermined value, and at the same time decrease the eccentric rotational movement speed N of the consolidation head 14,
When the detected value exceeds a predetermined value, the shield propulsion speed V is lowered and at the same time the eccentric rotational movement speed N of the consolidation head 14 is increased.

Due to the eccentric rotational movement of the consolidation head 14, the portion of the object to be excavated 16 that is pressed against the object 16 gradually shifts in the circumferential direction, but this is the result of the consolidation head 14 moving as if rolling on the object to be excavated 16. The excavated object 16 itself is pushed out linearly in the axial direction of the shield body 10 without rotating in the circumferential direction. In this case, the effect of discharging the excavated material 16 into the shear chamber 22 increases as the earth pressure increases, which results in the exact opposite of the conventional method of discharging the excavated material while rotating the cutter.

In the embodiment shown in FIG. 2, the consolidation head 26 is eccentrically rotated and rotated at a position in front of the shield body 24, and a thrust is exerted on the shield body 24 during the eccentric rotation of the consolidation head. Then, the axial force acting on the consolidation head 26 is detected.

The consolidation head 26 is located offset from the center of the shield body 24 by an amount e, and a portion of its outer circumferential surface is sized to protrude radially outward from the shield body 24. The consolidation head 26 makes an eccentric rotational movement relative to the shield body 24 and is simultaneously rotated. When the consolidation head 26 performs eccentric rotational movement and rotation in front of the shield body 24, the ground 28 around the consolidation head 26 is consolidated, and the shield body 24 is propelled into this consolidated area, so that the shield body 24 The frictional force acting between the ground and the ground 28 becomes smaller.

The axial force acting on the consolidation head 26 is detected, and the same operation as described above is performed based on this detected value.

FIG. 3 shows a shield propulsion device 30 that implements the shield propulsion method according to the present invention. A space 36 surrounded by an inner circumferential surface 34 is provided at the front of the shield body 32. The space 36 is formed into a conical shape whose diameter gradually decreases toward the rear. A consolidation head 38 is located within the space 36 and has its axis aligned with the axis 40.
It is arranged to surround the shaft 40 eccentrically by e from the axis of the shaft 40. A partition wall 42 is provided in the diametrical direction of the shield body 32 at the rear of the space 36 .

The shaft 40 is supported in two rolling bearings 46 arranged in the casing 44 behind the partition wall 42 and in a rolling bearing 50 arranged in a bearing part 49 of the rib 48 in front of the space 36.

Eccentric sleeve 5 arranged around shaft 40
2 has an eccentric portion 54 having a circular outer shape, and a shaft portion 55 extending rearward from the eccentric portion. The eccentric portion 54 is provided with a hole having an axis located at a position offset by e from the center of the circle. This hole extends into the shaft section 55, where its axis coincides with the center of the circle. The shaft portion 55 projects rearward through a rolling bearing 56 arranged on the bulkhead 42. The hole of the eccentric sleeve 52 is formed in a loose fit with respect to the shaft 40, and the eccentric sleeve 52 is supported by the shaft 40 via a pair of needle bearings 58 arranged at both ends of the hole. On the other hand, a ball bearing 60 is arranged on the front side of the eccentric sleeve 52, and this ball bearing 60 is locked by a stopper 62. Further, a ball bearing 64 is arranged on the rear side of the eccentric sleeve 54, and this ball bearing 64 is held by a gear described later. As a result, the eccentric sleeve 52 is rotatable relative to the shaft 40 and immovable in the axial direction.

A gear 66 is keyed to the shaft portion 55 of the eccentric sleeve 52, and this gear 66 meshes with a gear 70 keyed to the output shaft of the electric motor 68. On the other hand, a gear 72 is keyed to the shaft 40, and this gear 70 meshes with a gear 76 keyed to the output shaft of an electric motor 74.

Consolidation head 38 is rotatably supported on eccentric portion 54 of eccentric sleeve 52 via a pair of rolling bearings 78. As is clear from the above description, since the eccentric sleeve 52 is rotated independently by an electric motor separate from the shaft 40, the rotation of the eccentric sleeve 52 causes eccentric rotational movement and friction with the excavated object. The consolidation head 38, which is rotated by the shaft 40, rotates at its own rotational direction and speed, regardless of the rotational direction and speed of the shaft 40.

A concrete pipe 78 is installed behind the shield body 32.
is connected, and the shield main body 32 is propelled by a pusher jack 80 arranged at the rear thereof. Two tubes 82, 84 are provided that open in front of the partition 42. One pipe 82 is a pipe that supplies muddy water etc. to the shear chamber 86, and the other pipe 84 is a pipe that supplies muddy water etc. to the shear chamber 86.
This is a pipe that conveys the excavated material discharged at 6 to the rear. Furthermore, a cutter 88 is attached to the front end of the shaft 40.

A device for carrying out the shield propulsion method shown in FIG. 2 is the shield propulsion device shown in FIG. What is necessary is just to form it in the size which becomes the outer side of the radial direction.

The axial force acting on the consolidation head 38 passes through the shaft 40 and acts on a rolling bearing 46 arranged in the casing 44 behind the bulkhead 42. Therefore, a load cell 90 is placed between the casing 44 and the front rolling bearing 46 to detect the axial force. This detected value is indicated by one pointer of the multi-point indicator 94 of the control panel 92, and the other pointer of the multi-point indicator 94 is used to set a predetermined value of the axial force. A signal is sent from the control panel 92 to the electric motor 68 via a frequency converter 96 such as an inverter to change the rotation speed of the electric motor 68. Also, a signal is sent from the control panel 92 to the power unit 100 of the main push jack 80 via the frequency converter 98.
Changes the propulsion speed of the shield body. This control can be operated manually or automatically.

The axial force acting on the load cell 90 is a reaction force of the earth pressure generated on the excavated object, and this earth pressure reaction force is between the active earth pressure and the passive earth pressure of the ground. Therefore, it is convenient to convert the pressure into the settings and instructions of the multi-point indicator.

Before propelling the shield propulsion device 30 into the ground, first calculate the earth pressure of the ground to be excavated, find the range from active earth pressure to passive earth pressure,
Set one pointer of the multi-point indicator to a relatively high value. Thereafter, the electric motor 68 and the electric motor 74 are driven to rotate the consolidation head 38 while eccentrically rotating it. During this period, pressure oil is supplied from the power unit 100 to the original pusher jack 80, and the shield body 32 is supplied with pressure oil through the concrete pipe 78. give thrust to
Promote this. When the shield body 32 is propelled, an axial force is applied to the load cell 90, which is indicated by the other pointer of the multipoint indicator 92. This detected value is compared with a set value, and the rotation speed of the electric motor 68 is changed via the frequency converter 96, or the rotation speed of the electric motor (not shown) of the power unit 100 is changed via the frequency converter 98, and the above-described operation is performed. do.

(Effects of the Invention) According to the present invention, instead of guiding the excavated material to the discharge port while rotating it within the shield body, the excavated material is guided straight to the discharge port by consolidation and earth pressure reaction force. Because of this, the frictional force between the excavated object and the bulkhead is reduced, and the consolidation head rolls against the excavated object, so the power applied to the consolidation head can be reduced. In addition, for those that rotate the consolidation head eccentrically in front of the shield body,
The frictional force acting between the shield body, the pipe, and the ground is reduced, and the propulsion power can be reduced.

In addition, by changing the rotational speed of the consolidation head and/or the propulsion speed of the shield body in response to fluctuations in earth pressure, it is possible to cope with or synchronize with the fluctuations, thereby quickly improving safety against accidents such as ground collapse. can be secured.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory diagram showing a propulsion method according to the present invention, FIG. 2 is a cross-sectional explanatory diagram showing another propulsion method according to the present invention, and FIG. 3 is an apparatus for carrying out the propulsion method shown in FIG. FIG. 10, 24, 32: Shield body, 12, 3
6: Space, 14, 26, 38: Consolidation head, 4
0: shaft, 52: eccentric sleeve, 80: main push jack, 90: load cell, 92: multi-point indicator,
96, 98: Frequency converter.

Claims (1)

[Scope of Claims] 1. A consolidation head is eccentrically rotated and rotated in front of a partition wall provided in the diametrical direction of the shield body, and during this time a thrust is applied to the shield body to propel the shield body into the ground. , detecting the axial force acting on the consolidation head from the ground or its excavated material, and when the detected value exceeds a predetermined value, reduce the propulsion speed of the shield body or reduce the eccentric rotational speed of the consolidation head; A shield propulsion method that raises the shield. 2. The shield propulsion method according to claim 1, wherein the consolidation head is eccentrically rotated within a space of the shield body provided in front of the partition wall. 3. The shield propulsion method according to claim 1, wherein the consolidation head is eccentrically rotated at a position in front of the shield body. 4. The shield propulsion method according to claim 1, wherein the axial force is detected by a load cell placed behind the partition wall. 5. The method according to claim 1, wherein the predetermined value is set by one pointer of a multi-point indicator, and the detected value is indicated by another pointer of the multi-point indicator. Shield propulsion method. 6. The consolidation head is eccentrically rotated and rotated in front of the partition wall provided in the diametrical direction of the shield body, and during this period, a thrust is applied to the shield body to propel the shield body into the ground, and the consolidation head is moved into the ground or its covering. A shield propulsion method that detects an axial force acting on the consolidation head from an excavated object, and when the detected value exceeds a predetermined value, reduces the propulsion speed of the shield body and simultaneously increases the eccentric rotational movement speed of the consolidation head. .