JP2016205036A - Open shield method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an open shield method, which enables a fixing bolt to be fastened and fixed for preventing displacement of box bodies to each other during construction (box body installation) based on the open shield method and also the fixing bolt to be loosened to be used as a flexible joint when a reaction force is not necessary for the box bodies, and can ensure waterproofness with a belt-like sealing material such as a rubber packing and a joint material before and after the flexible joint is made.SOLUTION: In an open shield method, a joint groove is formed on an inner end face of a concrete box body 4. When a new concrete box body 4 is suspended in a tail part of an open shield machine and connected to an existing concrete box body 4, a cushioning material is inserted between the concrete box bodies 4, a belt-like sealing material such as a rubber packing is set and those concrete box bodies 4 are fastened with each other with a fixing bolt. A liquid joint filler that becomes elastic after curing is charged into the joint groove formed between the combined concrete box bodies 4 to form a flexible joint.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an open shield method for constructing underground structures such as water and sewage systems and underground passages in an urban area.

  The open shield method is a rational method that makes use of the advantages of the open cut method (open cut method) and the shield method, and is promoted using an upper open type shield machine (open shield machine) while preventing sediment collapse. This is a method of laying a box inside.

  7 and 8, the outline is shown in FIG. 7. In FIG. 7, reference numeral 1 denotes an open shield machine, which is a shield machine having left and right side wall plates and bottom plates connected to these side wall plates, with front, rear and top surfaces opened. .

  The open shield machine 1 is divided into a plurality of bodies in the front-rear direction, and the front end of the rear body as the tail portion 1b is fitted into the rear end of the front body as the front portion 1a. The middle bent portion 2 is formed to be bendable.

  The front part 1a is mainly used for excavation, and has a front end and an upper surface as open surfaces. Inside the machine body, the middle jacks are arranged on the left and right and rearward and rearward in a plurality of stages.

  On the other hand, the tail portion 1b is used to install the concrete box 4 and has a bottom plate 5, and the propulsion jack (shield jack) 3 is directed to the front and rear in the body, and is moved up and down. It is arranged in multiple stages.

  In the figure, 6 is a slide earth retaining plate provided at the front end of the front portion 1a, and 8 is a press bar (push angle).

  Next, an open shield construction method using such an open shield machine 1 will be described. Although illustration is omitted, the open shield machine 1 is installed in the start shaft and the propulsion jack 3 of the open shield machine 1 is extended. Then, the open shield machine 1 is moved forward by taking the reaction force against the reaction wall in the starting pit, and the first concrete box 4 forming the underground structure is suspended from above by a lifting machine 14 such as a crane, It is set behind the propulsion jack 3 contracted in the tail 1b portion of the open shield machine 1.

  The excavator 7 such as an excavator excavates and removes soil from the front or upper surface of the open shield machine 1. At the same time as or after this earth removal step, the propulsion jack 3 is extended to advance the open shield machine 1.

  Then, the second concrete box 4 is suspended in the tail portion 1 b of the open shield machine 1 in front of the first concrete box 4. Thereafter, the same soil removal process, advance process, and setting process of the concrete box 4 are repeated as appropriate, and the concrete boxes 4 are sequentially left in the ground as the open shield machine 1 moves forward. 4. Backfill the upper surface of 4.

  When the concrete box 4 is suspended in the tail part 1b of the open shield machine 1, a height adjusting material such as a concrete block is disposed under the concrete box 4 and the concrete part 4 is placed inside the tail part 1b. Filling the backside injection material 9 using the instantaneous setting grout material in the left and right and lower gaps of the box 4 to perform the primary injection, and after the open shield machine 1 moves forward, as a secondary injection, the concrete box Back injection material 9 is injected from the inside of 4 to the outside by a grout hole.

  In this way, if the open shield machine 1 reaches the reaching mine, it is removed and the construction is completed.

  By the way, the concrete boxes 4 buried in a column in the ground are fixed bolts when a new concrete box 4 is suspended in the tail portion 1b of the open shield machine 1 with respect to the existing concrete box 4. The fixing portion 10 is formed by fastening.

  The concrete boxes 4 forming the fixing unit 10 are connected to each other, although not shown in the drawing, through-holes in the front-rear direction are provided at the corners, and those connected in tandem are connected by tightly connecting PC steel bars such as long bolts. .

  Further, a ring-shaped joint having a T-shaped cross section called a collar may be interposed between the concrete boxes 4 and 4 at the front and rear positions, and the front and rear concrete boxes 4 may be connected by this collar.

  By the way, in the underground structure by such a concrete box 4, it is requested | required that the connection of concrete boxes 4 should be made into a flexible joint as a countermeasure against earthquakes, such as an earthquake, and a ground subsidence in soft ground.

Regarding the flexible joint of such a concrete box, for example, there are the following patent documents.
JP-A-9-60099 JP 2001-295251 A

  Patent Document 1 discloses a flexible structure that is used for connecting portions of the box culverts when constructing joint grooves and sewers by connecting and installing a large number of closed cross-section box culverts having a space in the center. The box culvert is provided with a water stop plate at the connection portion between the box culverts around the space of the box culverts, and the box culverts are connected by a PC steel rod. The water plate is configured to follow the displacement of the installation position of each box culvert that occurs due to softening of the installation ground, earthquake, etc., while maintaining the water stop effect of the connecting portion, and the PC When the steel rod exceeds the design displacement amount of the water stop plate, the steel bar can suppress the displacement and prevent the water stop plate from being damaged. It is flexible coupling structure in box culvert, characterized in that is configured to be maintained by the fixing portion capable of following the design displacement water plate.

  Patent Document 2 discloses a flexible joint structure of a precast culvert composed of a pair of concrete boxes and joints connecting the joint end faces of the concrete box, and the joints are provided inside the joint end faces. A solid-type flexible connecting member with embedded end portions, a flexible member filled in a gap between the joint end surfaces, and an outer peripheral surface and / or an inner peripheral surface of the joint portion of the pair of concrete boxes A flexible joint structure of a precast culvert, which is composed of a filling type flexible member which is filled in a concave portion and which is liquid at the time of filling and has a rubber elastic function after being cured.

  In the open shield method, excavator such as excavator excavates and removes soil from the front or top surface of the open shield machine, and advances the open shield machine by extending the propulsion jack at the same time or after this earth removal process. Thus, since the concrete box receives a reaction force of the jack thrust, a firm fastening is required at the time of installation, and thereafter, the connection between the concrete boxes 4 is required to be a flexible joint.

  The purpose of the present invention is to consider the special characteristics of the open shield method, and when fixing the open shield method (when installing the box), the fixing bolt can be fastened and fixed to prevent the box and box from slipping, When the reaction force on the box is no longer needed, the bolt fixing part can be loosened to make a flexible joint, and it is reliable because it is done with both a band-like sealant and joint material by rubber packing etc. An object of the present invention is to provide an open shield method that can ensure water-stopping in any case before and after forming a flexible joint.

  In order to achieve the above-mentioned object, the present invention includes a step of excavating and discharging soil in front of the front or upper surface opening of an open shield machine in which a propulsion jack is disposed inside the left and right side wall plates, and the front, rear and upper surfaces are opened. The process of advancing the shield machine using the concrete box composed of the left and right side panels, the upper floor board, and the lower floor board as a reaction force to extend the propulsion jack, and the new concrete behind the propulsion jack shrunk in the tail part of the shield machine In the open shield method of burying concrete boxes in tandem by repeating the installation process of hanging the box from above and joining it to the existing concrete box, joint grooves are formed on the inner end face of the concrete box. When a new concrete box is suspended from the existing concrete box in the tail part of the open shield machine and connected, A rubber cushion or other cushioning material is interposed between the two boxes, and a belt-like sealing material such as rubber packing is arranged. The concrete boxes are fastened with fixing bolts, and the concrete boxes are formed with each other. The gist of the invention is to form a flexible joint by filling the joint groove with a joint material that is liquid and becomes elastic after curing.

  According to the present invention, during the construction of the open shield method (when the box is installed), the fixing bolt is tightened and fixed, so that the box and box can be prevented from slipping even when the reaction force of the jack thrust is received. In addition, the rebound resilience of cushioning materials such as rubber prevents the fixing bolts from loosening, and the so-called point touch where the end faces are only partially in contact with each other at the connecting part of the concrete box, stress is concentrated on the contact part. Can prevent the concrete from being damaged.

  In addition, with regard to the water stoppage of the connection part of the concrete box, the joint material filled in the union joint groove formed between the concrete box and the band-shaped sealing material affixed to the end face of the concrete box The water stop can be secured. Thus, since it carries out by both the strip-shaped sealing material by rubber packing etc. and joint material, even if any one is incomplete, water stop is reliable.

  On the other hand, when the reaction force on the box is no longer needed, the bolt fixing part can be loosened to make a flexible joint that can follow the behavior of the concrete box. In that case, the joint material filled in the joint joint groove is Since it becomes rubber elastic after curing, the bolt fixing part can be loosened, and even if the concrete box is displaced, it can extend and keep water still.

  As described above, the open shield method of the present invention can fix the fixing bolt to prevent the box from slipping when the open shield method is installed (when the box is installed). When it is no longer needed, the bolt fixing part can be loosened to make a flexible joint, and since it is performed with both a band-like sealing material and a joint material made of rubber packing, etc., it is reliable. It can be secured in both cases.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a concrete box used in the open shield method of the present invention. The concrete box 4 is made of reinforced concrete or PC concrete, and includes a left side plate 4a, a right side plate 4b, an upper floor plate 4c, and a lower floor plate 4d. The front and rear surfaces are open as openings.

  Furthermore, the concrete box 4 is provided with an insert (bolt insertion hole) 12 for joining together.

  The tip of the insert (bolt insertion hole) 12 is formed as a sheath hole 16 as shown in FIG. 5, and a box opening hole for forming the fixing portion 10 is provided at the tip.

  Moreover, the concrete box 4 is a flexible joint for providing earthquake resistance as an underground structure, and the present invention interposes a cushion material 11 such as rubber between the concrete boxes 4 and rubber packing or the like. A belt-like sealing material 13 is provided.

  The cushion material 11 is a wide band plate that covers the end surfaces of the left side plate 4a and the right side plate 4b of the concrete box 4 along the vertical direction.

  The sealing material 13 is a belt-shaped sealing material having a rectangular cross section (20 mm × 30 mm) pasted in a shallow groove extending in the circumferential direction formed on the end face of the concrete box 4 as shown in FIGS. There is.

  Moreover, the joint groove 20a was formed in the inner end surface of the concrete box 4, and when the concrete box 4 connected mutually, the joint groove 20 was formed by these joint grooves 20a.

  The outline of the open shield construction method is as described with reference to FIGS. 7 and 8. The open shield machine 1 is installed in the start shaft, and the propulsion jack 3 of the open shield machine 1 is extended to start. The open shield machine 1 is moved forward by taking the reaction force against the reaction wall in the mine, and the first concrete box 4 forming the underground structure is suspended from above by a lifting machine 14 such as a crane. 1 is set behind the propulsion jack 3 contracted in the tail 1b portion.

  The excavator 7 such as an excavator excavates and removes soil from the front or upper surface of the open shield machine 1. At the same time as or after this earth removal step, the propulsion jack 3 is extended to advance the open shield machine 1.

  Then, the second concrete box 4 is suspended in the tail portion 1 b of the open shield machine 1 in front of the first concrete box 4. Thereafter, the same soil removal process, advance process, and setting process of the concrete box 4 are repeated as appropriate, and the concrete boxes 4 are sequentially left in the ground as the open shield machine 1 moves forward. 4. Backfill the upper surface of 4.

  In this way, if the open shield machine 1 reaches the reaching mine, it is removed and the construction is completed.

  The open shield method of the present invention also suspends a new concrete box 4 from the tail part of an open shield machine and connects it to the existing concrete box 4 and guide pins (not shown) are inserted into the guide pin insertion holes 15 for positioning. Insert).

  Further, the fixing bolt 17 is inserted into the sheath hole 16 as a metal fitting for preventing it from coming out, and the fixing unit 10 is fastened with the nut 22 with the fixing unit plate 21 interposed therebetween.

  When the concrete box 4 is connected, the union joint groove 20 is filled with the backup material 23 and the elastic joint material 24 and sealed.

  As the elastic joint material 24, for example, two liquids of a modified silicone resin having elasticity and durability and an epoxy resin are mixed, become elastic after curing, follow the movement of the joint, and exhibit water-stopping properties. However, other joint materials may be used as long as they have adhesion to the joint portion and followability to the displacement of the concrete box during an earthquake after filling.

  Until the new concrete box 4 is installed, the sealing members 13 are separated from each other as shown in FIG. 2 and FIG. 3A. However, when the nut 22 is temporarily tightened in FIG. 2 and 3B, the sealing materials 13 are in pressure contact with each other in a crushed state.

  Further, the cushion material 11 attached to the existing concrete box 4 is sandwiched between the concrete boxes 4.

  When the excavation is completed and the reaction force is no longer necessary for the concrete box 4, the fixing bolt 17 is loosened, and the fixing bolt 17 is fixed by interposing a cushioning material 18 with a buffer rubber ring. The mortar 19 is filled to form a flexible joint.

  Next, the displacement of the concrete box 4 at the time of an earthquake will be described. As shown in FIG. In some cases, opening and compression of the joints may occur, or in a disconnected state, opening may occur.

  The concrete box 4 behaves as if the joints are open in the detached state, and the concrete box 4 behaves as if the joints are opened in the bent state. 4 (C), the cushioning material 18 is deformed so as to be crushed, and follows the change of the concrete box 4.

  Further, at this time, as shown in FIG. 2 and FIG. 3C, the seal members 13 are slightly crushed, but the pressure contact between them is maintained, and the water stopping property is secured.

  Furthermore, the elastic joint material 24 follows the gap even when the joint interval is widened, and continues water stopping.

It is a perspective view which shows one Embodiment of the concrete box used for the open shield method of this invention. It is explanatory drawing which shows the change according to a box state by A arrow view of FIG. It is explanatory drawing which shows the change according to a box state by the arrow B figure of FIG. It is explanatory drawing which shows the change according to the box state of a fixing | fixed part. It is a side view of a concrete box. It is explanatory drawing which shows the displacement of the concrete box at the time of an earthquake. It is explanatory drawing at the time of box installation of an open shield construction method. It is explanatory drawing at the time of the box connection of an open shield construction method. It is a side view of the completed underground structure by the open shield method.

DESCRIPTION OF SYMBOLS 1 ... Open shield machine 1a ... Front part 1b ... Tail part 2 ... Folding part 3 ... Propulsion jack (shield jack)
4 ... Concrete box 4a ... Left side plate 4b ... Right side plate 4c ... Upper floor plate 4d ... Lower floor plate 5 ... Bottom plate 6 ... Slide retaining plate 7 ... Excavator 8 ... Press bar (push angle)
9 ... Back injection material 10 ... Fixing part 11 ... Cushion material 12 ... Insert (bolt insertion hole)
DESCRIPTION OF SYMBOLS 13 ... Sealing material 14 ... Lifting machine 15 ... Guide pin insertion hole 16 ... Sheath hole 17 ... Fixing bolt 18 ... Buffer material 19 ... Non-shrink mortar 20 ... Combined joint groove 20a ... Joint groove 21 ... Fixing part plate 22 ... Nut 23 ... Backup material 24 ... Elastic joint material

Claims (1)

Protrusion jacks are disposed inside the left and right side wall plates, and a step of excavating and discharging the earth and sand ahead of the front or upper surface opening of the open shield machine having the front, rear and upper surfaces opened, The process of advancing the shield machine with the reaction of the concrete box composed of the upper floor board and the lower floor board, and a new concrete box hung from the upper side behind the propulsion jack shrunk in the tail part of the shield machine. In the open shield method of burying concrete boxes in columns one after another by repeating the installation process to join the concrete box as appropriate,
A joint groove is formed on the inner end face of the concrete box, and a band-shaped sealing material that can be pressed against each other is pasted on the end face of the concrete box.
When a new concrete box is suspended and connected to the existing concrete box in the tail part of an open shield machine, a cushioning material such as rubber is interposed between the concrete boxes to fix the concrete box to each other. Fastened with bolts to press the band-shaped sealing materials together, and the joint joint groove formed between the concrete boxes is filled with a joint material that is liquid and elastic after hardening to form a flexible joint. Open shield construction method characterized by

Images