JPH0517354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an enlarged shield construction method for constructing an enlarged portion in a part of a shield tunnel, and a lining member used therein.

[Conventional technology]

The conventionally known expansion shield construction method involves removing a segment of the primary lining of a tunnel constructed by the conventional shield construction method from the tunnel by cutting it open and widening it. There is a method of proceeding with the reconstruction of the expansion section and segments, and a method of sequentially pressing the segments for the enlarged part while excavating in the direction perpendicular to the tunnel axis using a special excavation device installed inside the tunnel primary lining constructed using the ordinary shield method. There is a method of obtaining the required enlarged space by drawing out the space.

[Problem that the invention seeks to solve]

In recent years, many tunnels in urban areas have been constructed using the shield method due to local environmental problems such as traffic obstruction, vibration and noise, and deepening of tunnels due to congestion of underground structures.

However, most of the manholes necessary for cable connections and connections have traditionally been constructed by excavating from the ground.

Due to their functionality, manholes are often installed under road intersections, such as at highway intersections in commercial areas and where traffic and underground objects are congested.
Constructing shafts using the open-cut method has become difficult due to various problems such as the impact on the local environment, traffic, and ensuring safety, and there is a desire to develop manhole construction technology that does not involve the open-cut method.

In order to meet this demand, the expansion shield method described above has recently been developed, but in one method, the ground is exposed in the mine as the mine is cut and expanded, so a chemical solution is applied in advance. It is necessary to improve the ground in the enlarged excavation area by injection, etc., and even if there are other methods to avoid exposing the ground, special excavation equipment must be installed inside the mine, and the hole drilled in the segment must be improved. Extrusion of the segment must be carried out while excavating the ground through the section.

An object of the present invention is to make construction of an expanded section in a part of a shield tunnel safer and more reliable without exposing the ground in the expanded section or installing a dedicated excavation device inside the tunnel. The object of the present invention is to provide a construction method that can be constructed economically and economically, and lining members for carrying out the construction method.

[Means for solving problems]

In order to achieve the above object, the expansion shield construction method according to the present invention uses an overcutter installed on the rotary cutter to adjust the surrounding ground of the area to be expanded to the enlarged shape while a closed rotary cutter shield machine is in the process of excavating a tunnel. The over-drilling is carried out, and mud with plastic fluidity is injected into this over-drilling part from inside the shield machine, and the over-drilling part is filled with mud and excavated, and then the shield machine follows. After or during excavation of the planned expansion section, at least a part of the existing segment of the planned expansion section is removed from the mine together with a short cylindrical expansion wall forming member attached to the inside of the segment. The underground space is partially enlarged by extruding mud into the over-drilling section filled with mud.

Further, the lining member for an expansion shield according to the present invention includes a segment for an expansion part that has dividing surfaces parallel to the segment extrusion direction when expanding the underground space at both ends, and a grout hole in the middle part, and a segment for the expansion part that has a grout hole in the middle part. an outer shell part attached to the inside of the segment and forming a joint part with the segment of the non-expanding part on the same plane as the dividing plane of the segment for the enlarged part, and removably coupled to the outer shell part, It consists of a short cylindrical enlarged part wall surface forming member divided into an inner shell part forming both side walls perpendicular to the tunnel axis direction between the joint parts.

The expansion shield lining member described above is used directly in carrying out the expansion shield construction method according to the present invention.

[Effect]

In the enlarged shield construction method according to the present invention, the ground is maintained and the posture of the shield is maintained by filling the area over-excavated by overcutter with mud having plastic fluidity. In order to expand the underground space, the existing segment of the planned expansion section and the wall forming member of the enlarged section attached to it are pushed out of the tunnel into the over-drilling area filled with this mud. It is safe because it can be carried out without exposing it to the ground, and there is no need for preliminary ground improvement or enlarged excavation from inside the mine. Then, by using the existing segment pushed out into the over-excavation area and the expansion part wall forming member attached to this, the size can be adjusted to any desired size.
It is possible to construct an enlarged space of the shape.

Furthermore, by using the expansion shield lining member according to the present invention, during the expansion work, the outer shell and inner shell of the expansion part wall forming member are formed into an integrated short cylindrical shape and are attached to the expansion part segment, and together with the expansion part segment. The necessary expanded space can be obtained by sequentially extruding it from the mine, and after completing the expansion work, remove the inner shell of the expansion wall forming member other than the starting point and end point of the planned expansion section. . Since the inner shell and the outer shell can be removably connected with bolts or the like, the inner shell can be easily removed and does not require cutting in the mine. In addition, when extruding a segment, in order to maintain the earth pressure necessary for stabilizing the ground, mud is discharged into the mine from the over-drilling area through the grout hole of the segment, or
If necessary, on the other hand, mud can be injected into the over-excavation area.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 11.

FIG. 1 is a schematic diagram showing a shield construction state before construction of an enlarged portion in the direction of the enlarged shield according to the present invention. In the figure, 1 is an earth pressure type shield machine shown as an example of a closed rotary cutter shield machine, which includes a shield hull 2, a rotary cutter 3, an over cutter 4 built into the cutter spoke, a chamber 5 for taking excavated soil, and a chamber. 5, a screw conveyor earth removal device 6 for discharging the excavated earth and sand into the shield machine; It is equipped with an earth pressure gauge 9 that measures the earth pressure inside the chamber 5, and as a necessary element for the expanding shield construction method of the present invention, an over-drilling is carried out from inside the shield machine on the outer periphery of the shield hull 2 behind the rotary cutter 3 using an overcut cutter 4. Mud injection port 1 for injecting mud into the excavated area
Earth pressure gauge 1 that measures the earth pressure in the 0 and over-drilling areas
1 is equipped. 12 is a segment of the normal section constructed following the shield machine 1; 13,1
3' is a segment used in the planned expansion section L of the shield tunnel, 13 is a segment for an enlarged portion, and 13' is a segment for a portion that will not be expanded. 14 indicates the ground.

Figure 2 shows over cutter 4, mud injection port 10,
This is an enlarged schematic sectional view of the front part of the shield machine equipped with an earth pressure gauge 11. The mud inlet 10 and the earth pressure gauge 11 are provided at multiple locations in the hood of the shield hull 2, and the mud inlet 10 connects the mud feed pipe 15. It is connected to a mud pump (not shown) installed inside the machine.

For excavating the tunnel in the normal section, use the rotary cutter 3.
is rotated to excavate the ground 14, and the viscosity-imparting liquid (bentonite solution, etc.) injected from the injection port 7 at the tip of the rotary cutter 3 and the excavated soil are stirred and mixed with the stirring blade 8 to create plastic fluidity. The chamber 5 is filled with mud having a
This is done by discharging the soil using a screw conveyor soil unloading device 6 while controlling the soil. Then, each time the trench is dug a predetermined distance, the segments 12 are assembled by a segment construction device (not shown). The segment 12 constructed in this manner has a circular cross section as shown in FIG. 3, which is the same as a normal primary lining cross section. However, if you want to expand the underground space by only a portion of the total length of the tunnel, such as a manhole that serves as a cable connection base or a shelter for a subway,
For example, when it is desired to enlarge the cross section shown in FIG. 3 to the cross section shown in FIG. 4, the construction method is performed using the following procedure.

In Figure 1, the entire length of the primary tunnel lining other than the L section is constructed in exactly the same manner as the normal shield method, and from the time the starting point of the planned expansion section L is reached,
Using the over cutter 4 built into the cutter spoke, the surrounding ground of the shield is excavated to match the enlarged shape as shown in Fig. 5. The over cutter 4 used for over-drilling is expanded and contracted by a hydraulic jack 16 shown in FIG. 2, etc., and is capable of securing an over-drilling amount of, for example, 300 mm or more.

At the same time as over-drilling, mud 17 having plastic fluidity is poured into the chamber 5 by the screw conveyor 6 from inside the shield machine through the mud inlet 10.
The debris taken into the aircraft can be used as is, or if necessary, some of the debris can be removed. ) is pressurized and injected using a mud pump (not shown). As a result, the excavated soil in the over-drilling area is moved to the chamber 5 side, that is, the face side of the entire surface of the shield machine, and the mud 17 is moved to the over-drilling area.
The excavation is carried out while applying pressure to maintain the soil pressure necessary to hold the ground, and the segments 13 and 13' are assembled every time the excavation is carried out a predetermined distance. Segment 1 is used to assemble segments 13 and 13'.
The same segment construction equipment can be used for assembly 2. The assembled shape of the segments 13, 13' at this point is a circular cross section as shown in FIG. 6, and the outer diameter is the same as the outer diameter of the segment 12 in the assembled state.

The dividing planes of the segments 13 and 13' are formed parallel to the extrusion direction during expansion, and as shown in FIG. A flange 19 is provided with a bolt hole 18-1 for the purpose. FIG. 7 is a diagram showing an example of the enlarged segment 13, which is formed into a box shape from steel, and in addition to the bolt holes 18-1, segment connecting bolt holes 18-2 and 18-2 are also provided on the side and dividing surfaces. 3 is provided.

In order to maintain the pressure of the mud 17 filling the over-drilling portion at a value necessary for stabilizing the ground during and after the completion of trenching in the planned expansion section, the mud injection port 10,
In addition to the earth pressure gauge 11, some or all of the grout holes 20 of the segments 13 are also equipped with an earth pressure gauge 27, a stop valve 28, a mud injection
A discharge hose 29 is attached, and mud injection is controlled based on the measured value of the soil pressure gauge. Although excavation in this section is particularly careful to prevent the shield from meandering, the amount of mud injected into the over-excavation portions on both sides shown in FIG. 5 can be adjusted as necessary.

Next, the underground expansion work will be explained.

FIG. 8 shows an example of an enlarged section wall forming member (hereinafter abbreviated as an enlargement adapter) 21 used in this construction method.

The expansion adapter 21 is composed of an outer shell part 21-a and an inner shell part 21-b. Outer shell part 21-
a is a part that forms a joint part with the segment 13' of the part that does not expand on the same plane as the dividing plane of the segment 13 for the enlarged part, and the inner shell part 21-b is a part that forms a joint part between the joint parts in the tunnel axial direction and This is the part that forms the right-angled side walls. Both parts 21-a and 21-b are made so that they can be connected or removed with bolts, etc., and are used as an integrated short cylinder as shown in Figure 8 during enlargement work, and the enlargement work is completed. After that, except for the first and last expansion adapters of the planned expansion section, the inner shell portions 21-b of the remaining expansion adapters are removed. The outer shell portion 21-a remains bolted to the existing segment 13 of the enlarged portion at the flange 22 even after the enlargement work is completed, and becomes a permanent structure forming an enlarged wall surface together with the segment 13. Outer shell part 2
1-a, the inner shell part 21-b has connection bolt holes 23-1, 23-2, 23-3, 24-1, 2 on each surface.
4-2 and 24-3 are open.

Figure 9 is an enlarged diagram of the work procedure of this construction method. 9th
In the figure, 25 is an extrusion device used to extrude the expansion adapter 21 together with the existing segment 13 from inside the mine to an over-excavation section filled with mud. The extrusion device 25 is a device separate from the segment construction device installed in the shielding machine 1, and has a pressing portion 25-2 that can be expanded and contracted by a hydraulic jack or the like on a rod 25-1 that can move up and down and change direction. The reaction force of pressing is received by the primary lining via a reaction force receiver (not shown). This device is mounted on a truck (not shown) that runs on rails 26 installed in the mine.

Although Fig. 9 shows an example in which the enlarging work is performed on one side of the tunnel, simultaneous work on both sides is also possible.
This becomes possible by changing the structure of 5.

FIG. 10 shows a cross section taken along the line AA in FIG. 9.

Expansion work using this method will be carried out in the following order.

(1) Attach the expansion adapter 21 to the existing segment 13 of the expansion part with bolts.

(2) Press the inside of the expansion adapter 21 with the extrusion device 25.

(3) Remove the connecting bolt of the existing segment 13 with the expansion adapter 21 attached to the other segments 12 and 13', and insert the bolt hole 18-2,
Attach a water stop valve (not shown) to 18-3.

(4) Extend the rod 25-1 of the extrusion device 25 and gradually push out the expansion adapter 21 and the segment 13 connected thereto from the mine. At this time,
Mud is discharged or injected through a stop valve 28 and a hose 29 under control based on the measured value of an earth pressure gauge 27 connected to the grout hole 20 of the segment 13 so as to maintain the pressure of the mud necessary for stabilizing the ground.

(5) Bolt holes 23-1, 23-2, 24-1, 24- inside the extruded expansion adapter 21
2 and the bolt holes of segments 12 and 13' of the existing segments that will not be expanded, stop the extrusion operation, and remove the expansion adapter 2.
One side and upper and lower end surfaces of 1 are connected to segments 12 and 13' of the non-enlarged portion with bolts.

(6) From the second ring onward of the segment 13 in the enlarged part, in addition to bolt connection work on the upper and lower end surfaces of the extruded enlargement adapter 21, it is necessary to perform bolt connection work on one side of the extruded segments 13. . It goes without saying that the sliding parts of the segments and the expansion adapter should have the required sealing function.

The above operations are repeated one after another to expand the underground space. The enlarging operation may be performed for each segment, or may be performed for a plurality of segments at the same time. At the end of the expansion section, one side and upper and lower end surfaces of the extruded expansion adapter 21 are connected with bolts to the segments 12 and 13' of the non-expansion portion in the same way as at the start.

(7) After completing the above work, enlarged segment 13
Back-filling was carried out through the grout hole,
Permanently stabilizes the ground in the excavated area.

(8) The expansion adapters 21 at the start and end points of the expansion section can be filled with concrete or the like to reinforce the start and end points.

(9) The inner shell part 21-b of the expansion adapter 21 is removed from areas other than the starting point and end point of the enlarged section, leaving only the outer shell part 21-a necessary as earth retaining.

This concludes the work to expand the primary lining underground space using this method. Figure 11 shows the underground space expanded by this construction method. Shaded areas 30 and 31 in the figure are reinforcement points at the start and end points of the enlarged section.

The above-mentioned enlarging work may be carried out either after the completion of excavation of the section to be enlarged or during excavation.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, as an enlarged shape of the tunnel, the fourth
As well as when expanding on both sides as shown in the figure
It is possible to expand in any direction including one side, upper side, lower side, etc. Also, the shielding machine used is not limited to the model that converts excavated earth and sand into mud within the chamber, and it can be expanded depending on the construction conditions. You can select the model that suits you, and the mud to be injected into the over-drilling area can be made separately. Other equipment and construction procedures may also be modified as appropriate within the scope of the present invention.

〔Effect of the invention〕

According to the present invention, (1) A dedicated excavation device is brought into the primary lining mine in order to carry out expanded excavation (extra excavation) using a long overcutter equipped on a closed rotary cutter shield machine. Enlarged excavation can be done efficiently without any problems.

(2) Over-drilling Since the excavation is carried out while injecting plastically fluid mud into the excavated area from inside the shield machine, it is possible to maintain the ground and maintain the posture of the shield by managing the earth pressure in this area. can.

(3) Work safety can be ensured because the ground is not exposed inside the mine.

(4) No ground improvement is required in the planned expansion section.

From the above, it is possible to construct an enlarged portion in a part of the shield tunnel safely, reliably, and economically.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the shield construction state before construction of the expanded section in the expanded shield construction method of the present invention, Figure 2 is a schematic sectional view of the main part of the shield machine used in this construction method, and Figure 3 is the non-expanded section. A cross-sectional view of the primary lining, Figure 4 is a diagram showing an example of the tunnel cross-section of the enlarged section by this construction method, Figure 5 is a cross-sectional view showing the state of mud injection in the over-excavation section, and Figure 6 is the same as Figure 1. Figure 7 is a perspective view showing an example of the configuration of an expansion segment, Figure 8 is a perspective view of an example configuration of an expansion adapter, and Figure 9 is an outline of the expansion work. FIG. 10 is a cutaway plan view taken along the line A-A in FIG. 9, and FIG. 11 is a cutaway plan view of an enlarged portion constructed by this construction method. 1...Shield machine, 2...Shield hull, 3...
...Rotating cutter, 4...Over cutter, 5...Chamber, 6...Earth removal device, 10...Mud inlet,
11...Earth pressure gauge, 13...Segment for expansion part,
12, 13'... Segment of the part that will not be enlarged,
15...Sludge feeding pipe, 21...Enlargement adapter (enlarged part wall surface forming member), 21-a...Outer shell part, 21-
b...Inner shell part, 25...Extrusion device.

Claims (1)

[Claims] 1. While excavating a tunnel using a closed-type rotary cutter shield machine, an over cutter equipped on the rotary cutter excavates the surrounding ground of the area to be expanded according to the shape of the expansion. We are planning to expand by injecting mud with plastic fluidity into the over-drilling area from inside the shield machine and digging while filling the over-drilling area with mud to build a segment that will follow the shield machine. After the excavation of the section is completed or during excavation, at least a part of the existing segment of the section to be expanded is filled with mud from inside the mine together with a short cylindrical expansion part wall forming member attached to the inside of the segment. This expansion shield method is characterized by partially expanding the underground space by extruding it into the excavated area. 2. A segment for an enlarged part that has dividing surfaces parallel to the segment extrusion direction when expanding the underground space at both ends and has a grout hole in the middle part; An outer shell part forming a joint part with a segment of a part that does not expand on the same plane as the dividing plane, and a part removably connected to the outer shell part, and a joint part on both sides perpendicular to the tunnel axis direction between the two joint parts. A lining member for an enlarged shield comprising a short cylindrical enlarged part wall forming member divided into an inner shell part forming a wall.