JPS603395A - Central cutter of shield drilling machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention, Field of Industrial Application) The present invention is a shield tunneling machine with a cutter face plate provided at the center of a rotary circular cutter and a central force.

This invention relates to a shield excavator which is configured with a tunnel excavator, and which presses the face ground in an optimal state when excavating the tunnel.

(Prior Art, Problems and Technical Fields) As is well known, a conventional shield excavator consists of a cylindrical body and a rotary circular cutter installed at its front end, and the cutter is rotated and advanced underground. Earth and sand is cut and introduced into a chamber behind the cutter through an opening in the cutter, and is discharged by a conveyor or the like, and as the cylinder moves forward, lining segments are assembled on the peripheral wall surface after passing through the cylinder. The assembled end face of the lining becomes a stand for the shield jack, and by extending the shield jack, the trunk of the excavator can be advanced. Figure 1 is a side view showing an example of a well-known shield tunneling machine.
The cutting blade 2 is equipped with a required number of cutting blades 7. Reference numeral 3 denotes a lining segment 1-, and the peripheral wall after the shell 1 passes through is hardened by the lining segment. The earth and sand cut by the rotation and advancement of the rotary circular cutter 2 is cut by the same cuckoo 2.
It enters the rear chamber 4 through the opening of and is carried rearward by the conhair 5. 6 is a shield jack used for advancing the torso.

In such conventional shield excavators, when excavating the ground, a gap is created after the cutting blade passes through, and the ground above the excavated tunnel becomes loose in order to take in the cut soil from the opening, and the ground above the front of the cutter is loosened. This can cause the collapse of the ground and subsidence of the ground surface.

Therefore, in order to prevent the ground from loosening or collapsing during excavation, it is necessary to press the ground with a constant pressure with the face plate while cutting.

As a prior art of the present invention, there is Japanese Patent Publication No. 46-7754. The device described in this publication has a "center cutter with a hollow auger in the center and an Archimedean spiral blade around it, which discharges excavated soil in the radial direction. A rotary circular cuckoo for mechanized shield tunnel Ih single machine, in which the excavated soil is guided and discharged through the soil discharge opening provided around the central cutter.
Its gist is: However, with such a central cutter, the volume of the soil packed in front of the central force after cutting the ground is not equal to the volume when the soil was in the ground, and varies depending on the soil quality. It is not possible to adjust the amount of soil in front and behind, and if the soil clogged in front of the central cutter tends to expand after cutting, the clogged soil will press against the central cutter and the force required for cutting by the central cutter will increase, causing force and rotation of 7 turrets. If the soil packed in front of the central cuckoo tends to contract after cutting, a gap will be created between the central cuckoo surface and the face surface, and the pressure with which the central cuckoo presses against the ground will decrease.

(Objective of the present invention) The present invention eliminates such problems and excavates while applying stable pressure to the face in front of the central cutter, which is near the center of the tonosho in the face ground, thereby reducing the increase in loosening of the face ground. It is an object of the present invention to provide a central cutter device which is designed to minimize.

(Technical Means) The present invention is composed of a rotary circular cutter having an opening for discharging earth and sand from a cutter face plate of a shield excavator, and a central cutter having no earth and sand discharge port provided at the center, and the central cutter discharges the excavated soil. A shield excavator having a spiral blade that discharges in the radial direction as it rotates and advances, includes a mechanism that feeds soil replenishment material to the surface of the central cutter, and a mechanism that supplies the central cuckoo device to the ground. press with pressure 6
．． This is a central cutter device for a shield excavator, characterized in that it has a mechanism. To explain the present invention by way of examples, Fig. 2 is a side view of a shield excavator equipped with a central cutter according to the present invention, and Fig. 3 is a front view from the front of the shield machine, in which the face plate is a rotating circular cuckoo 2. and a central cutter 10. The rotary circular cutter has a required number of cutting blades 7 suitably arranged to cut the front face, and openings 1-18 with suitable arrangement and opening, and the central axis of the central cutter 10; Rotate around q9. In the configuration shown in FIGS. 2 and 3, the spiral-shaped curved blade forming the cutting edge of the central cutter 10 is, for example, an Alcinodes spiral blade.

As shown in FIG. 4, the shape of the Archimedean spiral blade is represented by r=a.theta. in polar coordinates.

a is a constant, r is the distance from the center of the central cutter to the helical blade at an arbitrary center angle θ, and h is the blade height of this helical blade. In Fig. 5, h-α b ・r 2π, S is the amount of advance of the central cutter in one rotation. α is the ratio of the volume of soil (■) cut by the central cuckoo and packed in front of the cutter to the volume Vo when the soil is in a natural pile, ie, α=■/■o.

The one shown in FIG. 6 is an example of a side cross-sectional view of the central cutter 10, which has an opening 11 in the face plate of the cuckoo so that the sleeve filling can flow out onto the surface of the face plate, and has a conduit 12 inside the central cutter. Reference numeral 13 denotes a replenishment reservoir, which is refilled through a conduit 14 rotatably connected from a separately provided replenishment supply device A. It also has a pressure holding mechanism 15 that presses the face plate against the face base at a constant pressure during rotation of the tar under medium heat power, and this mechanism utilizes the repulsive force of a known hydraulic piston or spring.

(Operation of technical means) Next, to describe the operation of the present invention, + is expressed as the above-mentioned formula % formula % at the height of the blade of the central cutter. If the volume of soil falling in a natural mountain (Vl) is unchanged from the volume (■) when the soil is being cut with a central cuckoo, then v-Vo is α-1, and V during cutting is
When the volume of Vo decreases from the volume of Vo, α<1, and when it increases, α>■. α does not depend on the pore ratio of the ground, but changes depending on the soil mechanical conditions, including the compressive characteristics of the soil, such as the ground pressure and the pressure during cutting, and the giratancy. If α〉■, the center cutter tends to expand during cutting, so the central cutter is pushed against the other threads, and the force required to cut the cutter increases, and the rotation of the cutter is inhibited, and if it tries to continue rotating, the blade will be damaged. Also α
If 1, the soil tends to contract during cutting, so that a gap is generated between the face and the center cutter face, and the pressure pressing down on the face and other ridges of the cuckoo decreases. When this α 1 is detected, replenisher is caused to flow out from the opening 11 in the face plate of the central cuckoo through the conduit 14.12.

This replenisher is used to fill the gap between the front of the central cutter and the ground face, but if it is clay with a high plasticity, it is used to reduce friction when the excavated soil moves on the surface of the central cuckoo. It is preferable because it is effective. If α〉l, the pressure applied to the center cutter is too large against the forward movement of the rotary circular cutter, so in that case, reduce the excessive pressure and apply pressure to maintain a constant pressure on the ground. Since the structure is such that the central force 7 can be retracted rearward by the holding mechanism 15, the amount of biting of the blade is reduced, and the force applied to the face can be made uneven. This rearward retraction structure is a known mechanism, and various mechanisms can be considered, such as using the anti-Ia force of a spring or using the action of a pressure accumulator that keeps the oil pressure of a hydraulic cylinder constant.

(Special effects of the present invention) 1- As described above, this invention uses a rotary circular cutter to cut the face of the ground in order to keep the pressure of the center cutter on the face of the ground at a constant level. -1- When there is a tendency to expand during cutting, the central cutter can be retracted backwards by the pressure holding mechanism, so the rotation of the central cutter is not inhibited, preventing damage or destruction of the blade, and also preventing soil from the ground. If there is a tendency to shrink during cutting, the CC pressing force is stabilized by the gushing of refill material, so L
The center of pressure (=J) is always held down with a constant pressure to keep the face rock in a stable state and prevent other rocks from loosening or collapsing during excavation. The shield tunneling machine can also be used rationally in terms of soil quality, which is extremely effective.

[Brief explanation of drawings]

Figure 1 is a side sectional view of a conventional shield tunneling machine, Section 2 is a side sectional view of a shield tunneling machine showing an embodiment of the present invention, and Section 3 is a side sectional view of a conventional shield tunneling machine.
The figure is a front view of Fig. 2, Fig. 4 is a drawing example of the blade of the central cutter, Fig. 5 is a sectional view taken along the line o-r in Fig. 4, and Fig. 6 is a side sectional view explaining the present invention in detail. be. DESCRIPTION OF SYMBOLS 1... Trunk, 2... Rotating circular cutter, 3... Lining segment, 4... Chamber, 5... Conhair, 6... Shield excavator, 7... Cutting blade, 8...
Earth and sand discharge opening, 9... Cutter center axis position, 10...
・Central cutter, 11... Opening, 12... Conduit, 1
3... Refill material reservoir, 14... Conduit, 15... Pressure holding mechanism. Figure i4-Figure

Claims (1)

[Claims] The cutter face plate of the shield excavator is composed of a rotary circular cutter having an opening for discharging dirt and a central cutter having no discharging port provided at the center thereof, and the central cuckoo rotates and moves the excavated soil forward in a radial direction. (11) In a shield tunneling machine having a spiral blade,
- A central cutter device for a shield excavator, characterized in that it has a mechanism for feeding earth and sand to the surface of the central cutter, and a mechanism for pressing the central cutter against the ground with a constant pressure.