JPS61146996A - Enlargement shield excavation method - 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 (Field of Industrial Application) The present invention relates to an enlarged shield excavation method for enlarging and excavating the periphery of an existing tunnel provided with a primary shield segment using a circumferential shield recess.

(Prior Art) The present applicant proposed the following method as the expanded shield excavation method (Japanese Patent Application Laid-open No. 106695-1983).

The primary shield segments of the planned expansion area of the existing tunnel with primary shield segments will be removed in series along the axial direction, the ground in the area to be removed will be enlarged and excavated, and a shield excavator for outer circumference excavation will be installed here. A guide ring having an annular groove opening to the inner circumferential surface along the circumferential direction is installed at both ends of the planned expansion area, and a guide ring is installed between the two guide rings in the annular groove on both sides of the shield excavator. The shield tunneling machine is fitted by engaging each of the formed one-shaped tabs, and the T-shaped tabs are fitted to the rear of the shield tunneling machine between both guide rings by engaging with the guide grooves. In this state, the circumferential segment is fixed, and the area to be expanded is expanded by alternately performing excavation with the shield excavator by pressurizing the circumferential segment with a jack and removing the primary shield segment.

(Problems to be Solved by the Invention) The construction method does not require the creation and backfilling of shafts, unlike the construction method in which a shaft is excavated from the ground surface in each area scheduled for expansion and a large diameter tunnel is added. When the shield machine reaches the area to be expanded, a special enlarging blade is attached to the cutter head of the shield machine, and the diameter of the tunnel created by the operation of the blade is expanded, such as a construction method in which the diameter of the expanded excavation remains constant. There are no structural defects that would make it impossible to resist earth pressure from the circumferential surface at a diameter greater than or equal to the diameter of All of the steps can be done in the same place, which improves work efficiency. However, work efficiency is poor because the shield tunneling machine is propelled, and the circumferential segment assembly and segment removal are performed alternately. Since the existing tunnels and circumferential segments in the planned area will be in a missing circle state, they will not have sufficient resistance against the surrounding soil nosho, and therefore reinforcement work will be necessary if the soil nosho is large.

It is an object of the present invention to provide an expanded shield excavation method that eliminates such inconveniences.

(Means for Solving the Problems) The present invention provides a means for expanding the area to be expanded in an existing tunnel in which a primary shield segment is provided and guide rings are installed in advance at both ends of the area to be expanded. The primary shield segments are removed in series along the axis, the ground in this removed area is excavated, a shield excavator for outer circumference excavation is installed here, and the shield excavator is slidably attached to both guide rings. The circumferential segments are then fixed one after another with the guide rings slidably attached to the rear in the propulsion direction of the shield tunneling machine, and the circle at the rearmost end.

By pressurizing the circumferential segments, the shield tunneling machine sequentially excavates in the circumferential direction of the existing tunnel along the guide ring, and the rear of the tunneling shield tunneling machine is sealed by continuous fixation of the circumferential segments, and the area to be expanded is sealed. In the expansion shield excavation method for expanding and creating land, a ring having an annular groove opening on the outer peripheral surface is used as the guide ring,
The shield tunneling machine and the circumferential segments sequentially fixed to the rear thereof are engaged with the grooves of the guide ring, and the shield tunneling machine is moved along the guide ring in the circumferential direction of the existing tunnel without removing the primary shield segment. The method is characterized in that after the tunnel is excavated and the area to be expanded is expanded, all primary shield segments within the area to be expanded are removed.

(Implemented!> Embodiments of the invention will be described with reference to the drawings.

When constructing the existing tunnel (2) with the primary shield segment (1) into the ground (3), the segment (11) existing outside the planned expansion area (4) and the area (
4) A guide ring (6) each consisting of a plurality of ring segments and having a guide annular groove (5) opening on the outer peripheral surface along the circumference of the existing tunnel (no) at the boundary with the segment (12) existing within the existing tunnel. to be placed.

To excavate the planned expansion area (4), first construct the existing tunnel (2) and then excavate the segment (12) within the area (4).
) of the lower segments (12') are removed in series along the axial direction, and also the lower ring segments (7a) of the ring segments (7) forming the guide ring (6) are removed. , as shown in FIG. 4(a), the steel frame is a removable frame that vertically communicates with the ground (3) exposed by the removal of the segment (12') in the area (4). A steel box (8) is installed, and the steel box (8) is press-fitted into the earth (3) by extending the jack (9) as shown in Fig. 4(b). Then, the steel boxes (8) are stacked, the jacks (9) are extended, and after the tip of the steel box (8) reaches the specified depth of the ground, the soil is discharged and used for the forward base. The creation of the cavity (IO) is completed.At this time, the bottom plate (8a) for earth retention is attached to the bottom of the steel box (8) that was first sunk, and the direction of propulsion of the shield excavation wait of this steel box (8) is side plate (8
b) Remove.

As shown in FIG. 5, the shield digging IN (+1) is composed of a roughly rectangular cutting edge part (+21) and a main body part 03 which is a U-shaped frame, and the circumferential segment a41 is a sixth
As shown in the figure, the main body part I of the shield tunneling machine at+
It has a U-shaped frame body that is roughly similar to '13, and has T-shaped ears (151ae) on both upper ends of the frame body.
In the area, the shield excavation Ia11'D and the circumferential segment (l@) are sequentially fitted between both guide rings (6) (6), and by providing propulsive force to these, the area to be expanded [(4
) will be created. That is, both guide rings (6) with the lower ring segments (7a) (7a) removed.
) In (6), the T-shaped ears (+51) formed on both sides of the shield excavation wav are engaged with the grooves (5) formed on both guide rings (0) (6), and the shield excavation machine a1
(Fig. 2, Fig. 4 (C)), and furthermore, both guide rings (6) (
6), attach the T-shaped ear piece (lG) to the guide ring (6) (
6) and attach the circumferential segment a/D by engaging with the groove (5), and fix this circumferential segment (joining edge 07 of l@) to the joining edge ae of the shield excavation mat by fastening with a bolt or the like. 4 (d)), and then the shield tunneling machine 0 is expanded and pressurized by the jack a9 of this circumferential segment aΦ.
Propel 1) in the direction of the arrow and push it towards the ground in front (3)
The ground inside the shield tunneling machine ai) (3)
is excavated by hand or by an appropriate excavation means such as an earth auger attached to the center of the shield excavator 0v (not shown), and then a guide ring (6
) (6) Engage each T-shaped ear piece (le into the groove (9) of the guide ring ae and insert the other circumferential segment (141 (lΦ...
・Sequentially install the last circumferential segment a of the
The shield excavator (In) is excavated by pressing 4, and the shield excavation is 1 m by tightening the joint edges (+7) between each circumferential segment a@ (Fig. 4 (e)).
, the shield excavator a excavates in the direction of the arrow and discharges earth and sand to expand and create the area to be expanded (4). Finally, the bottom plate (8a) and side plate (8C) of the steel box (8) are removed, and the shield tunneling machine a1 is moved into the cavity a.
Return to the inside of e and remove it from the guide ring (6) (6).
Engage each T-shaped lug (le) of the circumferential segment (l@) into the groove (5) of the ring segment (1a) that was removed first, and insert both ring segments (7aH7a) into said segment (11) (h). and then remove all the segments (12) in the area to be expanded (4). Thereafter, the circumferential segment a is fixed to the guide ring (6), for example by welding. Thus both guide rings <6) ( The enlarged tunnel ■ consisting of the circumferential segments (l@) fixedly connected on the entire circumference between 6) is completed, and the enlargement construction work is completed (FIG. 4(f)).

In the above embodiment, in order to facilitate the installation of the shield tunneling machine at+ and the circumferential segment a@ between both guide rings (13) and (6), each guide ring (6) is divided into shield tunneling machine IIF. (Before installing +1 and circumferential segment l'l@, some of the ring segments (7a) were removed and reinstalled after these were installed, but each guide ring (6) and the shield excavator ( +1) and the shape of each ear piece as Ge of the circumferential segment a@, it is possible to adopt a configuration in which it is not necessarily necessary to divide or remove it.

(Effects of the Invention) The present invention is an enlarged shield excavation method in which the shield excavator excavates to enlarge the outer periphery of a part of the shield segment while sequentially excavating along a guide ring. The shield tunneling machine and the circumferential segments to which it is fixed in sequence to the rear are engaged with the grooves of the guide ring, and the shield tunneling machine is guided around the existing tunnel along the guide ring. After digging in the direction of the tunnel and expanding the area where the tunnel is planned to be expanded, all primary segments within the area where the tunnel is planned to be expanded are removed, making the work easier than the method previously proposed by the applicant. Moreover, during the expansion, the existing tunnel in the planned expansion area maintains its circular shape, so it has a large resistance against the surrounding earthen walls, which has the effect of not requiring any reinforcement work.

[Brief explanation of drawings]

Figure 1 is a schematic partial perspective view of the existing tunnel with some shield segments applied, Figure 2 is a vertical sectional view of the existing tunnel in Figure 1, and Figure 3 is an enlarged view of the part in Figure 2. Figure, 4th
Figures (a) to m are cross-sectional views taken along the line in Figure 2 - ■ showing the steps of the excavation method according to the present invention, Figure 5 is a perspective view of the shield excavator, and Figure 6 is a perspective view of the circumferential segment. show. (1)...Primary shield segment (2)...Existing tunnel (4)...Planned expansion area (5)...Annular groove (6)...Guide ring (7>...Ring segment (9)... Jacket (I+)... Cavity for forward base (1... Shield tunneling machine 0Φ... Circumferential segment a9... Jacket ■... Expansion tunnel N size

Claims (1)

[Claims] The primary shield segments of the area to be expanded in an existing tunnel, in which primary shield segments have been applied and guide rings along the circumferential direction of the area to be expanded are installed in advance at both ends of the area to be expanded, are removed in series along the axis; The ground in the area to be removed is excavated, a shield excavator for outer circumference excavation is installed here, the shield excavator is slidably attached to both guide rings, and a shield excavator is installed at the rear in the direction of propulsion of the shield excavator. The circumferential segments are sequentially fixed while being slidably attached to both guide rings, and by applying pressure to the circumferential segment at the rearmost end, the shield excavator is sequentially moved along the guide rings in the circumferential direction of the existing tunnel. In an expansion shield excavation method in which the area to be expanded is expanded by sealing the rear of the shield excavator by continuously fixing the circumferential segments, the guide ring has an annular groove opening on the outer circumferential surface. using things,
The shield tunneling machine and the circumferential segments sequentially fixed to the rear thereof are engaged with the grooves of the guide ring, and the shield tunneling machine is moved along the guide ring in the circumferential direction of the existing tunnel without removing the primary shield segment. 1. An expansion shield excavation method, which comprises: excavating a tunnel to expand an area to be expanded; and then removing all primary shield segments within the area to be expanded.