JPS5921892A - Method of construction of expansion shield excavation - 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] The present invention involves enlarging and excavating an area of an existing tunnel where shield segments have been partially installed using an expanding shield machine that propels the outer periphery in a direction perpendicular to the axis. This is related to the expansion shield method.

The shield method is often used as an excellent construction method for tunnel excavation for subway construction and underground cable burying work, but when performing work to connect sand underground cables that have built subway stations, it is necessary to It becomes necessary to enlarge the section.

Conventional methods for carrying out the above expansion work include, for example, digging a vertical shaft for each area planned for expansion, and when the area planned for expansion is reached, expanding shield excavation is carried out by adding an enlarged blade to the cutter head of a shield machine. A method was taken.

However, in recent years, the former has become increasingly difficult to implement in view of the fact that tunnel construction routes have become deeper underground due to restrictions from various aboveground and underground obstacles in urban areas. There was also a problem in terms of cost, as all but one part had to be backfilled after the expansion work.0 Also, in the latter case, the diameter of the excavation is limited because if the diameter of the expanded excavation becomes large, it will not be able to counteract the soil from the surrounding surface. In addition, it is not possible to simultaneously excavate a normal diameter tunnel and excavate an enlarged section, and the enlarged blade section must be attached and detached each time.

Therefore, the applicant of the present application first proposed a tunnel expansion excavation method that improves these conventional methods. This new construction method involves creating an enlarged excavation section for the shielding machine's launch base at the end of the planned expansion area in the tunnel where the next shielding has been carried out.
Here, an expanding shield machine that is propelled in the axial direction along the outer periphery of the next shield segment is installed, and the expanding shield machine is propelled to perform expanded excavation, and at the same time, expand excavation while sequentially removing some shield segments of the expanded excavation part. A secondary shield is applied to the part.

Therefore, in this application, we propose an expansion shield excavation method suitable for performing expansion excavation with a relatively short length in the axial direction, such as the expansion part for the starting base of the expansion shield machine that is propelled in the axial direction in the tunnel expansion method described above. It is something to do. That is, the present application is a method of enlarging and excavating the outer periphery of an existing tunnel in a direction perpendicular to the axial direction with respect to an area to be expanded in an existing tunnel in which a second shield segment has been installed, and in which a part of the shield segment in the area to be expanded is are removed in series along the axial direction 7, the other parts of this removed part are enlarged and excavated, and an enlarged shield machine is installed there, and at both ends of the area to be expanded, along the direction perpendicular to the axial direction, Each guide member is attached, and the base of the expanding shield machine is fitted into this guide member, and the outer circumference of a part of the shield segment is expanded while the expanding shield machine is sequentially propelled along the guide member by extension of the shield jack. The purpose is to excavate. This allows for easy expansion shield excavation, which eliminates the need to create a vertical shaft when performing expansion excavation, and allows for parallel work to create an expansion section in the necessary area without affecting normal tunnel excavation in any way. It is a construction method.

Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 (4) to (F) are explanatory diagrams showing the construction process.

First, as shown in Fig. 1 (5) process diagram and Fig. 2, the planned expansion area 2 is constructed around the outer periphery of the existing partial tunnel 1.
The lower segment 3a of the - next shield segment 3 is removed from the inside of the tunnel in series along the area to be expanded, and the segments 3 in the area to be expanded are removed.
The guide ring piece 5a attached to the segment 3a to be removed is removed from the splittable guide ring 5 attached in advance between the segment 4 and the adjacent segment 4 outside the planned expansion area.

In order to facilitate removal of the segments 3 in the area to be expanded, it is desirable to arrange them in advance in a base-divided manner, or to make the joint surfaces of each segment inwardly inclined.

2) Removed segment) Steel box 6 is placed at position 3a.
Set up.

This steel box 6 has a rectangular cylindrical frame body, and at least a plate member in a direction perpendicular to the axis of the tunnel is removably stretched by screw means, and a jack (not shown) protrudes into the frame body. A reception area is provided.

Next, as shown in the step (B) in FIG. 1, a jack 7 is installed between the jack holder of the steel deck 6 and the - next shield segment on the upper side, and the steel deck 6 is expanded by the extension of the jack. It is pressed into the ground 8 and excavated inside it by hand digging or other excavation means. After the first steel box 6 has been sunk 10 times, similar steel boxes are stacked on top of each other, and the jacks are extended to lower them into the ground 8, and the process of excavating the inside of the boxes is repeated to a predetermined depth. Then excavate the inside.

Next, as in the step in FIG. 1(C), a bottom plate 6a is attached to the bottom surface of the steel box 6 that was first sunk.

The above-mentioned steel box 6 is for retaining the earth and is set to prevent the collapse of the ground 8 in the excavated portion, but it may be omitted depending on the soil quality.

As shown in detail in FIGS. 3 and 4, the removed idling piece 5a is installed in the expansion shield machine 9 in a steel box 6, and the guide ring 5 is returned to its original annular shape. Then, the steel box 6 and the guide ring piece 5a are tightly connected to the segments 4 outside the area adjacent to both sides of the area 2 to be expanded. The enlarged shield machine 9 is equipped with a skin plate 9a having a cutting edge formed at the tip on the outer circumferential side, and a shield jack 9b mounted within the skin plate, similar to a general shield machine. The base of this shield jack 9b is pivotally attached to the inside of the hood, and the cylinder protrudes rearward.

The expanding shield machine 9 has an arc shape that matches the circumference of the expanding excavation by the skin play 9a, and a part of the inner diameter part is formed in an arc shape that is approximately equal to the outer diameter of the shield segment 3.4.
On the tip side of the inner diameter part, there is a cutting edge 9 similar to the skin plate described above.
C, and a leg piece 9d having a cross-sectional shape is provided to protrude from the inner diameter portion in order to fit into the guide ring 5. On the other hand, the guide links 5 are arranged in the circumferential direction. Each guide ring piece 5 is divided into the same number as the next shield segment.
A is assembled into an annular shape, and its cross-sectional shape is formed into a groove shape into which the legs 9d of the expansion shield machine 9 can be fitted, as shown in FIG.

Therefore, the expansion shield machine 9 can freely slide along the guide ring 5, and in this case, although not shown, in order to improve the slidability between the leg piece 9d and the guide ring 5, the expansion shield machine 9 can move freely along the guide ring 5. Sliding members such as rollers and sliding plates can be attached.

In the above embodiment, in order to facilitate the fitting of the expanding shield machine 9 onto the guide ring 5, the guide ring is made splittable, and some of the guide ring pieces 5a are separated before the expanding shield machine is fitted. I removed several pieces and reattached them after fitting them, but the guide ring 5 and the leg piece 9 of the expansion shield machine
Depending on the shape of d, it is possible to adopt a configuration that does not necessarily require dividing or removing.

In addition, a configuration in which the guide ring 5 is installed in advance between the next shield segments 3 and 4 inside and outside the planned expansion area 2 is also possible, in which the guide ring is installed along the inner periphery of the next shield segment 4 adjacent to the planned expansion area. If you do this, there is no need to install it in advance, and the guide member can be replaced with a guide ring and formed into an angular frame.
It is also possible to create a rectangular enlarged section other than a circular enlarged section by slightly changing the shape of the enlarged shield machine.

Continuing to explain the step in FIG. 1(C), a reaction force receiver 10 is attached to the inner surface of the sunken steel plate opposite to the direction in which the expanding shield machine 9 is propelled within the TUX 6, and this reaction force receiver 10 and the An enlarged shield segment 11 having the configuration shown in FIG.
It is fixed to the guide ring 5 as shown in the figure.

This enlarged shield segment 11, like a normal shield segment, may have a slightly different shape depending on the mounting angle position, but basically, as shown in Fig. The base of both side plates is provided with a mounting hole 11a for attaching to the guide ring 5, and adjacent enlarged shield segments are connected to each other by screw means at the edges of the open front and rear faces. 8- A mounting hole 11b for mounting is provided.

Although not shown, reaction force receivers for the shield jack 9b are provided on the inner surfaces of both side plates of the enlarged shield segment 11.

Next, as shown in step ) in FIG. 1, among the side plates of the submerged steel box 6, the front side plate 6b on the side that propels the expansion shield machine 9 is removed, and the base is attached to the guide ring 5. The shield jack 9b is extended using the shield segment 11 as a reaction force receiver, and the expanding shield machine 9 is propelled along the circumferential direction, and the earth inside the expanding shield machine is manually excavated while pushing it into the ground in front. Although not shown, the enlarged excavation is performed using a suitable excavating means such as an earth auger attached to the center of the enlarged shield machine.

In this case, the reaction force of the expanding shield machine 9 is transferred from the pressed expanding shield segment 11 to the rear side plate 6 of the steel deck 6.
The force is transmitted to other mountains via the reaction force receiver 10 attached to c.

In the enlarged excavation part, a new enlarged shield segment 11 is arranged adjacent to the previous enlarged shield segment, and the base is connected to the guide ring 5 through the mounting hole 11a, and the opening edge is connected to the guide ring 5 through the hole 11b in some cases. and each is fixed to the recently expanded shield segment.

Thereafter, in the same process, the expanding shield machine 9 is sequentially propelled along the guide ring 5 to perform expanding excavation, and the expanding shield segments are sequentially attached as shown in FIG.
E) Partially removed shield segment shown in process) 3
Repeat until you reach the position where there is 3b (adjacent to a - next shield segment). In this case, the expanding shield machine 9 is propelled while the cylinder tip of the shield jack 9b is sequentially moved so as to balance the reaction force of the expanding shield segment adjacent to the rear of the shield machine. Especially at this point.”
If the collapse of the ground from three sides becomes a problem, use the attachment hole 11b of the expanded shield segment installed last to attach the earth retaining plate 12 here to prevent the collapse of the face, and also to prevent the collapse of the face. Remove segment 3b.

Then, in the same way as in the previous step, expanding excavation is carried out while propelling the expanding shield machine 9, and the work of sequentially attaching the expanding shield segments 11 is carried out to a position slightly in front of the steel box 6 shown in the step (F) in FIG. This is repeated, the side plate 6C of the steel box 6 is removed, and excavation is performed until just in front of the box.

Here, the leading end of the expanding shield machine 9 is attached to the expanding shield segment in the steel box that was attached first, the rear end of the expanding shield machine is attached to the expanding shield segment that was attached last, and the base side of the expanding shield machine is attached to the expanding shield segment that was attached last. They are integrally joined to the guide rings 5 by means of screws, and after removing the shield jack 9b, reaction force receiver 10, etc. of the expansion shield machine, the expansion shield segment 11 is also attached to the inside of the expansion shield machine 9. As a result, an expanded excavation is carried out across the entire outer periphery of the area to be expanded 2, and the outside of the expanded excavated portion is surrounded by the expanded shield segment 11, thereby making it possible to obtain an expanded tunnel from the collapse of another mountain. This expanding tunnel is constructed by assembling and installing another expanding shield machine inside that propels it in the axial direction of the tunnel, as shown by the imaginary line in Figure 6, and removing the front plate of the expanding shield segment in the - direction. In this state, it becomes a starting base for the expansion shield machine, and a long expansion excavation section can be created along the axial direction of the tunnel.

Of course, the expanded shield excavation method of the present application can be used not only for the above-mentioned starting base, but also for various other applications that require the creation of a relatively short expanded section within a tunnel.

In the above embodiment, the reaction force of the shield jack is received by the expansion shield segment adjacent to the expansion shield machine, but it is also possible to provide an appropriate reaction force receiving structure on the guide ring so that the reaction force is received by this. I can do it.

[Brief explanation of drawings]

Figure 1-(F') is a process diagram of the proposed excavation method, Figure 2 is a perspective view showing the area planned for expansion within the tunnel, and Figure 3 shows the state in which the expansion shield machine is fitted to the guide ring. 4 is a side view showing the propulsion state of the expanding shield machine, FIG. 5 is a perspective view of the expanding shield segment, and FIG. 6 is a front view showing the state in which the expanded shield segment is attached to the guide ring. It is. [Explanation of symbols] , 1...-Next tunnel 2... Expansion planned area 3
...Partial shield segment 4 within the planned expansion area...
・Next shield segment 5 outside the planned expansion area...
Guide ring 6... Steel box 7... Jacket 8... Earth 9... Expanding shield machine
10... Reaction force receiver 11... Expanding shield segment. Patent applicant Mitsui Construction Co., Ltd.

Claims (1)

[Claims] - An excavation method that expands the outer periphery along the direction perpendicular to the axis of an area scheduled for expansion of an existing tunnel in which shield segments have been installed, and in which a portion of the shield segments in the area scheduled for expansion are expanded in the axial direction. The area to be expanded is removed in series along the axis, and the ground in this removed area is enlarged and excavated, and an expansion shield machine is installed there, and guide members are installed at both ends of the area to be expanded along the direction perpendicular to the axis. ,
Fitting the base of the expansion shield machine into this guide member,
An expanding shield excavation method characterized by expanding and excavating the outer periphery of some shield segments while sequentially propelling an expanding shield machine along a guide member by elongating a shield jack.