JPH06100056B2 - Shield construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a shield construction method by a so-called pressure excavation method in which pressure is applied to the excavation surface by mud to excavate while preventing outflow of groundwater and collapse of the ground. Regarding the improvement of.

(Prior Art) In the conventional shield method by the pressure excavation method, a partition wall is provided in the front end portion of the shield cylinder, a rotary cutter head is provided in front of the partition wall, and mud is filled in the front side of the partition wall. The ground is excavated by the rotary cutter head while applying pressure to the face. In recent years, as a mud material,
Foaming agents and super absorbent resins are also used.

Further, in recent years, a cutting and kneading type pressure excavation method has been developed in which a rotary cutter head can be moved back and forth, and excavated earth and sand are mixed with a mud material, stirred, kneaded, and discharged as mud. There is.

In addition, these shield construction methods are to assemble segments into a cylindrical shape in the rear end of the shield cylinder in accordance with the excavation and sequentially extend the lining cylinder, which is smaller than the outer diameter of the shield cylinder. Therefore, a gap is formed between the ground excavation surface and the shield cylinder, and this gap is filled with a cement-based backfill material.

The backing material is injected after the lining through the injection holes opened in the segments of the lining cylinder.

(Problems to be Solved by the Invention) In the conventional shield construction method as described above, since the gap between the excavation surface and the lining cylinder is to be filled by backfilling after lining, the ground may collapse before backfilling. However, there is a problem in that ground subsidence is likely to occur due to loosening in the surrounding ground, and groundwater easily flows into this gap, which requires much labor for backfilling and water stoppage work.

In view of the conventional problems as described above, the present invention is a shield construction method which does not require backfilling work after lining, because the outer side of the lining cylinder assembled along with the excavation of the shield cylinder is automatically stopped and filled. It is intended to be provided.

(Means for Solving the Problem) A feature of the present invention for solving the above-described conventional problems and achieving the intended object is to provide a partition wall at the tip of a cylindrical shield tube, In the shield construction method in which a rotary cutter head is provided on the front side of the rotary cutter and the face is excavated and propelled by the rotary cutter head while stabilizing the face in mud, the outer diameter of the shield cylinder is provided at the end on the radial side of the rotary cutter. Providing a copy cutter for excavating larger, by pouring a liquid soil-improving material that is hardened with time from the copy cutter into the soil to stir the earth and sand at the shield cylinder outer peripheral position to give the earth and sand fluidity, It is to fill the gap between the lining cylinder and the ground by the segments that are sequentially assembled at the rear end of the shield cylinder with agitation fluidity sand and harden it with time.

The mud used in the present invention changes its viscosity depending on the soil quality of the ground to be excavated, and may have a viscosity commonly called muddy water in some cases.

The shield construction method of the present invention is a state in which the earth and sand outside the shield cylinder can flow by agitating the ground in a range larger than the outer diameter of the shield cylinder by a copy cutter and injecting a liquid improving material into the mixture to knead it. As a result of the excavation, the face pressure applied by the mud in the excavation section was transmitted to the outside of the lining cylinder at the rear end of the shield cylinder, and the kneaded earth and sand containing soil improvement material did not form a gap on the outer circumference of the lining cylinder. It is completely filled and it hardens over time.

(Example) Next, an example of an embodiment of the present invention will be described with reference to the drawings.

1 and 2 show an example of a state during excavation according to the present invention. In the figure, 1 is a shield machine and 2
Is a cylindrical shield cylinder, 3 is a partition wall provided in the front end of the shield cylinder 2 so as to partition the front and rear, 4 is a hydraulic jack for propulsion, 5 is an erector for segment assembly, and 6 is a segment made of steel or concrete. It is a tunnel lining cylinder assembled into a cylindrical shape by 7.

On the front side of the partition wall 3 is a spoke type cutter head 10 supported by a shaft 8 and driven to rotate by a hydraulic motor 9. The cutter head 10 can be reciprocated in the front-rear direction by a hydraulic cylinder 10a for sliding the cutter. Has become. Further, a plurality of mud material injection nozzles 11 are opened in the cutter head 10, so that the mud material is injected into the excavated soil at the same time as the excavation, and a constant mud pressure is constantly applied to the face 12 of the face. There is.

Reference numeral 13 is a cutter bit projecting from the cutter head 10.

Copy cutter at the tip of each spoke on the cutter head 10.
14 is projected. The copy cutters 14 are projected to a length that agitates the ground further outside the outer peripheral position of the shield tube 2, and each copy cutter 14 is provided with a plurality of soil improvement agent injection nozzles 15. Since then, a cement-based soil conditioner, which has fluidity and hardens over time, is poured into the soil.

Using the shield machine 1 configured as described above, the hydraulic motor 9 rotates the cutter head 10 via the shaft 8,
A necessary amount of mud material is injected, the face is excavated while applying a predetermined pressure, the excavated soil and the mud material are kneaded, and discharged as fluid mud by the screw conveyor 16. Then, in response to the excavation, a reaction force is applied to the tunnel lining cylinder 6 by the hydraulic jack 4, the shield machine 1 is propelled, the segment 7 is assembled according to the propulsion, the lining cylinder 6 is extended, and the digging is sequentially performed.

On the other hand, during this excavation, a copy cutter at the tip of the spoke
At the same time as agitating the ground located outside the outer peripheral surface of the shield cylinder 2 by 14, the soil improving agent is injected into the ground to give fluidity to the earth and sand at that position, and the cutter head 10
Simultaneously with the kneading of the excavated soil, the earth and sand around the ground are kneaded at that position to form an improved layer 17 having fluidity.

By thus propelling the shield machine while forming the improved layer 17 on the outer peripheral side of the shield tube 2, as shown in FIG. The mud pressure in the excavated portion is applied to the outer peripheral position of the cylinder 6, and the fluidized improvement layer 17 is applied to the shield cylinder 2 and the lining cylinder 6.
And the outer periphery of the lining cylinder 6 is densely filled with the improvement layer 17 without forming voids. Then, the improvement layer 17 is hardened with time, and the ground material 18 and the lining cylinder 6 on the outside are integrated.

Reference numeral 19 in the figure denotes a tail packing that seals the gap between the outer surfaces of the inner surface covering cylinder 6 of the shield cylinder 2.

(Advantages of the Invention) In the present invention, during shield digging, digging is performed at the outer peripheral position of the shield cylinder while forming a layer having fluidity that hardens with time, and between the natural ground and the tunnel lining cylinder by the segment. The following effects can be obtained by filling the gap.

(1) Since no gap is formed in the tunnel between the lining cylinder and the ground, the ground around the tunnel can be prevented from loosening, and there is no risk of ground subsidence.

(2) Back-filling work is no longer required after the tunnel lining cylinder with segments, so there is little manual work and a small number of people can perform construction.

(3) Immediately after excavation, the outer circumference of the tunnel lining cylinder is always covered with the kneaded hardly permeable mud, and since mud pressure is applied, water from the natural ground is suppressed, and water is stopped after lining. No need for treatment, and almost complete waterproofing is achieved by only temporary lining.

(4) Especially when constructing a shield tunnel in soft ground, the surrounding ground will be improved while excavating, and a stable tunnel will be constructed. Since the strengthened layer is formed on the periphery, a sufficient reaction force at the time of bending is obtained, and the planned bending can be easily obtained.

(5) In the backfill injection work, the deformation or breakage of the segment due to the injection pressure management error is eliminated.

[Brief description of drawings]

The drawings show an example of the embodiment of the present invention. FIG. 1 is a sectional view in a state of excavation, and FIG. 2 is a front view of the same. 1 ... Shield machine, 2 ... Shield cylinder, 3 ... Bulkhead, 4 ... Hydraulic jack, 5 ... Elector, 6 ... Tunnel lining cylinder, 7 ... Segment, 8 ... Shaft, 9 ... Hydraulic pressure Motor, 10 …… Cutter head, 11,15 …… Nozzle, 12 …… Face face, 13 …… Cutter bit, 14 …… Copy cutter, 16 …… Screw conveyor, 17 …… Improvement layer, 18 …… Solid ground , 19 …… Tail packing.

Front page continued (72) Inventor Tetsuo Furuta 2-8 Koraku, Bunkyo-ku, Tokyo Goyo Construction Co., Ltd. (72) Ken Ogasa 2-2-8 Koraku, Bunkyo-ku, Tokyo Goyoken Incorporated Co., Ltd. (72) Inventor Toshinori Teramoto 2-2-8 Koraku, Bunkyo-ku, Tokyo Goyoken Co., Ltd. (56) Reference JP-A-2-210198 (JP, A) Japanese Patent Publication No. 55- 547 (JP, B2) Japanese Patent Publication Sho 59-4033 (JP, B2)

Claims (1)

[Claims] 1. A shield provided with a partition wall at the tip of a cylindrical shield tube, and a rotary cutter head provided in front of the partition wall for propelling while excavating by the rotary cutter head while stabilizing the cutting face with mud. In the method of construction, a copy cutter for excavating a larger diameter than the outer diameter of the shield cylinder is provided at the end of the rotary cutter on the side of the radius of rotation, and a soil-curing material which is a time-curable liquid is poured into the soil from the copy cutter. At the same time, the earth and sand at the outer peripheral position of the shield tube are stirred to make the sand and sand flowable, and the gap between the lining tube and the ground is formed by the segments that are sequentially assembled at the rear end of the shield tube by the agitation fluidity sand. A shield construction method that is characterized by filling in and hardening over time.