JPH04258492A - Shield excavator - Google Patents

Abstract

PURPOSE:To obtain economically lining work having high safeness in a short time by a simplified method for the inner surface of tunnel. CONSTITUTION:An excavated soil pathway 20 leading to the rear end of a shield casing from the excavated portion is provided in the inside of the shield casing 10 of a shield excavator. A screw 21 is housed in the pathway 20 and excavated soil is partly sent backwards forcibly while being agitated. A hardener-injecting pathway 26 is also provided in the middle position of the pathway 20, and a hardener is injected to soil being sent in the pathway 26 and the soil mixed with the hardener is pressed into the space between the rear tunnel ground and the primary lining work of the segment 16.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield excavator that constructs an external lining on the outside of a primary lining made of segments while excavating.

0002

[Prior Art] Conventionally, a shield excavator of the type in which a primary lining is formed by segments is provided with an excavation mechanism at the front end of a cylindrical shield tube, and a segment assembly section within the rear end. The segments are assembled into a cylindrical shape in the assembly section, the previously constructed primary lining is extended, and the reaction force is taken to push out the entire shield excavator using a hydraulic jack for propulsion. The lining is pushed backwards and excavation is carried out. Then, the gap created between the primary lining and the tunnel ground surface is filled with backfilling material.

In many cases, a secondary lining made of cast-in-place concrete is provided inside the primary lining made of segments. The purpose of this secondary lining was mainly waterproofing, rust prevention, anti-vibration, and smoothing the inner surface of the lining (finishing).

0004

[Problems to be Solved by the Invention] The shield construction method using the conventional equipment as described above has the following problems. (1) When a shield tunnel is completed, the function of the secondary lining is generally that it is not a stressed member that receives external pressure, but does not need to be thick as long as it is smooth and has water-stopping and rust-preventing effects. Due to the workability of concrete, it should be at least several tens of centimeters thick.

[0005] Therefore, in order to ensure the thickness of the secondary lining, an extra cross section must be excavated using a shield excavator.

(2) Since the cross section of the primary lining increases by the thickness of the secondary lining, which is not a stress member, the design of the primary lining segment becomes excessive.

(3) In shield tunnels, it is difficult to perform primary and secondary lining in parallel in a narrow tunnel;
After the primary lining is completed, formwork is erected on the inner surface and the secondary lining is constructed, which requires a very long construction period.

(4) On the other hand, there are shield tunnels in which the secondary lining is omitted and the cross section is completed with only the primary lining, but this is not completely watertight and rust-proof, and may cause problems inside the tunnel.

(5) If an attempt is made to increase the voids on the outer surface of the primary lining and thicken the backfill material layer for waterproofing and stress reinforcement, the ground will tend to collapse after excavation and before filling with the backfill material. The surrounding ground becomes loose, making it easier for ground subsidence to occur.

[0010] In view of these problems, the present invention aims to provide a shield excavator that can construct a highly safe lining in a short time and economically at the same time as excavation, without requiring a secondary lining. It has been done.

[0011]

[Means for Accomplishing the Problems] The features of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose are as follows:
An excavation chamber is provided at the tip of the cylindrical shield tube, a rotary cutter head is provided at the front of the excavation chamber, a segment assembly section is provided at the rear end of the shield tube, and the segment assembly section is used to assemble the shield tube. In a shield excavator that excavates by taking a reaction force to the primary lining made of segments and simultaneously pushes the primary lining backward, an inner cylinder is fixed in a double cylindrical shape at a spaced interval inside the shield cylinder. providing an excavated earth and sand passage that communicates with each other in the front and back between the inner cylinder and the shield cylinder, a forced stirring feeding mechanism in the excavated earth and sand passage, and a curing agent injection passage communicating with the intermediate position of the passage; Further, the rear end portion of the cylinder is provided with a segment assembly portion.

0012

[Operation] The shield excavator of the present invention extends the primary lining by assembling segments inside the cylinder. Then, the shield excavator moves forward by taking reaction force from the primary lining. At this time, a portion of the earth and sand excavated by the cutter head at the front end of the shield cylinder enters the excavated earth and sand passage between the inner cylinder and the shield cylinder, and is stirred by the forced stirring and feeding mechanism at the rear end of the shield cylinder. Sent to the side. A hardening agent is injected from the hardening agent injection path in the middle of this passage,
It is sent to the rear end of the shield cylinder while being stirred. At the rear end of the shield tube, as the shield tube moves forward, a gap is created between the outer surface of the primary lining and the surface of the tunnel ground. The material is filled and hardened over time to form an outer lining that is integrated with the earth and the primary lining.

[0013]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

In the figure, reference numeral 10 denotes a shield cylinder, and inner cylinders 11 are fixed at intervals in a concentric arrangement inside the shield cylinder. At the front end of the inner cylinder 11, with a partition wall 11a in between, the front side thereof is an excavation part, and a cutter head 12 is installed in the front part so as to be driven to rotate around a shaft 13.

Inside the rear end of the inner cylinder 11 is a segment assembly section 14, and a propulsion jack 15 is installed on the front side of the segment assembly section 14.
Inside, the segments 16 are assembled into a cylindrical shape and the extended partial lining 17 absorbs a reaction force to propel the entire shield excavator. In the figure, 14a is a tail seal.

The shield cylinder 10 and the inner cylinder 11 are connected at both ends by a large number of radial connecting ribs 18 and 19, and the cylindrical gap between the cylinders 10 and 11 is used as an excavation earth passage 20. A ribbon screw 21 is rotatably housed in this passage 20 as a forced stirring feeding mechanism. A ring 23 is fixed to the inner peripheral surface of the ribbon screw 21, and a pinion 25 rotated by a drive motor 24 is engaged with a rack-shaped gear 23 provided on the ring 22, thereby driving the ribbon screw 21 to rotate.

[0017] A curing agent injection path 26, 26, .

Next, the excavation process by the shield excavator constructed as described above will be explained.

With the shield excavator stopped digging, the propulsion jack 15 is retracted, and the segments 16 are assembled into a cylindrical shape in the segment assembly section 14 behind it, and the primary lining 17 that has been constructed earlier is retracted. extend it. Thereafter, the propulsion jack 15 is extended, and the primary lining 17 takes up a reaction force to cause the entire shield excavator to dig.

At this time, the cutter head 12
A part of the excavated earth and sand enters the excavated earth and sand passage 20, and is moved rearward while being forcibly stirred by the drive of the ribbon screw 21. During the movement, the curing agent is injected from the curing agent injection paths 26, 26...
This is mixed and stirred to become the backfilling material 27 in a kneaded state and sent to the rear.

In this way, the backfilling material 27, which is mixed with a hardening agent added to the excavated soil, is press-fitted into the backfilling gap formed at the rear as the shield excavator excavates, and this An outer lining 29 that is hardened and integrated with the earth and the primary lining is formed.

In the above-described embodiment, the entire gap between the shield tube and the inner tube is used as the excavated earth and sand passage 20, but in addition to this, there are a plurality of cylindrical excavations on the inner surface of the shield tube 10, the front end of which opens into the excavation part. Earth and sand passages may be provided and a forced feeding screw may be accommodated in each passage.

[0023]

[Effects of the Invention] As described above, in the shield excavator of the present invention, the inner cylinder is provided at intervals inside the shield cylinder, and the segment assembly portion is provided within the inner cylinder. A thick backfilling space for the external lining is formed in the backfilling space, and a backfilling material made by mixing part of the excavated soil and a hardening agent is press-fitted into the backfilling space at the same time as excavation is being carried out.
A strong outer lining with a large wall thickness is formed, making it unnecessary to apply a secondary lining to the inner surface of the primary lining, significantly simplifying the lining work and shortening the construction period. It has become.

[0024] Furthermore, since the inner surface of the primary lining can be used as the finished inner surface of the tunnel due to the segments,
The diameter of the secondary lining can be smaller than that of the planned primary lining, which allows more leeway in segment design and eliminates the need for large tail seals.

Furthermore, instead of a secondary lining cast on-site, an outer lining is formed using the primary lining as a formwork using segments, so the thickness of the entire lining is reduced only to the stress. Since the thickness can be made close to that of the conventional method, the tunnel excavation cross section can be made smaller than that of the conventional method, making it highly economical.

Furthermore, a large space for external lining is formed as the excavation progresses, but at the same time as this space is formed, the lining material is pressurized and filled, which prevents loosening of the tunnel ground surface. Safe construction can be performed while preventing water leakage.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a shield tunneling machine according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG. 1.

[Explanation of symbols]

10 Shield tube 11 Inner cylinder 11a Partition wall 12 Cutter head 13 axis 14 Segment assembly department 14a Tail seal 15 Jack 16 Segment 17 Primary lining 18, 19 Connecting rib 20 Passage 21 Ribbon screw 22 Ring 23 Gyaa 24 Drive motor 25 Pinion 26 Hardening agent injection passage 27 Backfill material 29 Outside lining

Claims (1)

[Claims] 1. An excavation chamber is provided at the tip of a cylindrical shield tube, a rotary cutter head is provided at the front of the excavation chamber, a segment assembly is provided in the rear end of the shield tube, and the segment assembly is provided. In a shield excavator that excavates by taking a reaction force to the primary lining made of segments assembled in the section, and at the same time pushes out the primary lining backward, a double cylindrical structure is installed at a distance inside the shield tube. An inner cylinder is fixed to the inner cylinder, an excavated earth and sand passage is provided between the inner cylinder and the shield cylinder, which communicates with each other in the front and back, a forced stirring and feeding mechanism is provided in the excavated earth and sand passage, and a hardening agent is injected at an intermediate position of the passage. 1. A shield excavator characterized in that a passage is communicated with the cylinder, and a segment assembly section is formed inside the rear end of the cylinder.