JPS63107698A - Method of prestressed lining construction of shield tunnel in-place concrete and device thereof - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] "Prior Art" Conventionally, there was a prestressing technique for cylindrical concrete tanks. In a cylindrical concrete tank, a protrusion 2 is integrally provided on the outer periphery of the tank body 1 as shown in Fig. 22,
Using the side surfaces of this protrusion 2, both ends of the PC steel material 3a (in this application, the prestress steel material for introducing prestress is abbreviated as PC!fl material) buried in the tank body 1 are tensioned and prestressed. However, in the case of cast-in-place lining for shield tunnels, which is the object of the present invention, work on the outside of the cylinder (in this case, outside the tunnel, this space is filled with earth and sand) is not possible. This is impossible, and if this construction method is applied, it is necessary to provide a protrusion inside the tunnel, but this protrusion obstructs the internal space of the tunnel, especially in subway tunnels. It is necessary to bend with a large curvature (suddenly), which is a structural drawback.

Therefore, as a conventional method of introducing prestress into the concrete lining of a tunnel, Fig. 23 and 'f
, the method shown in Fig. 24 (Japanese Unexamined Patent Publication No. 191868/1986, hereinafter referred to as the first conventional example), the method shown in Fig. 25 (hereinafter referred to as the second conventional example),
conventional example), and the method shown in Fig. 26 (hereinafter referred to as 3rd example).
Conventional example) etc. have been proposed.

In the first conventional example, the prestressed steel materials 3b, 3b are buried in precast concrete 4 in advance, and cutouts 5, 5.5, . When combining a plurality of precast concretes 4 to form a ring, tension the PC steels 3b, 3b of the adjacent precast concrete 4.4 with a tensioning jig 6a shown in FIG. are fastened by a coupling 50a.

In addition, in the second conventional example, the PC steel materials 3c, 3c are arranged in the formwork and PC steel material holding ring 8 made of mouth-shaped steel, and the cast-in-place concrete 9 is placed through the formwork and PC steel material holding ring 8. This method introduces prestress, and at this time, the prestress introduced cannot be transmitted to the cast-in-place concrete 9 unless the connection between the formwork/PC steel retaining ring 8 and the cast-in-place concrete 9 has a rigidity of l-min. The formwork and PCW
Shear transmission reinforcements 10, 10, 10, . . . are provided protruding from the four-material retaining ring 8 in order to integrate it with the cast-in-place concrete 9. In addition, in this second conventional example, it is possible to use a precast ring to which the precast concrete 4 of the first conventional example is applied instead of the formwork/PC steel holding ring 8, but in this case as well, Prestress is to be injected into the cast-in-place concrete 9, and it is also necessary to protrude shear transmission bars 10, 10, 10, . . . from this precast concrete ring.

Furthermore, in the third conventional example, the concrete placement part 9
A prestressed steel material 3d in the longitudinal direction (unless otherwise specified in the present application, the longitudinal direction means the longitudinal direction of the tunnel) which has been tensioned.

3d, 3d... and the PC steel materials 3e, 3e, 3e... in the circumferential direction (unless specifically limited in this application, the circumferential direction means the circumferential direction of the tunnel). , cast-in-place concrete 9 is placed.

“Problem to be Solved by the Invention 1 However, the above-mentioned first conventional example uses precast concrete 4 in which prestressed steel material 3b is buried;
The accuracy of the buried position of the C steel material 3b becomes a problem. If there is an error in the buried position of the PC steel material 3b, it may not only cause structural mechanical problems, but also make it difficult to connect the PC#4 materials 3C to each other, or in extreme cases, precast concrete 4.4.4.
...There is a problem that it becomes impossible to assemble the product itself.

In order to eliminate such problems, it is practically difficult to manufacture dozens of pieces of precast concrete 4 by burying each piece of PC steel 3b, 3b accurately, and this becomes a bottleneck in construction. is the actual situation.

In addition, in the second conventional example, when excavating with a shield machine,
As the reaction force receiver of the shield jack and press jack of the shield machine uses the end surface of the formwork/PCw4 material retaining ring 8, the shear transmission bars 10, 10, 10, . . .
It is impossible to attach the . Therefore, this shear transmission bar 10 will be installed underground, but according to a trial calculation, in the case of a tunnel with a diameter of 7 m, - about 100 reinforcing bars with a diameter of 25 mm are required per side of the formwork and 16W4 material retaining ring 8. Several hours (approximately 4-5 hours) are required for installation.

In this type of construction method, the excavation time per ring (distance to be continuously excavated at one time) is 2 to 3 hours, whereas in this method it takes more than twice as much time to install the shear transmission bars 10. As a result, the 4T method has the disadvantage of being difficult to implement due to its economical efficiency.

Furthermore, the third conventional example has a drawback in that it is difficult to accurately fix the positions of the longitudinal PC steel material 3d and the circumferential direction PC steel material 3e within the poured concrete. The reason for this is that in the cast-in-place lining construction method for shield tunnels, which is the subject of the present invention, the concrete is pressurized and press-fitted into the shield tail voids before the concrete has hardened, so the shape of the poured concrete changes. (Specifically, from Figure 16 to
As shown in Figure 7, in order to shorten the length mainly in the longitudinal direction,
In particular, the PC steel village 3e in the circumferential direction and its fixing material (not shown) may be deformed or moved. Moreover, in this persimmon structure, the position of the PC steel material 3e in the circumferential direction is very important, and even an error of about 1 cm in the radial direction of the tunnel causes a mechanical problem.

Therefore, the present invention has been made in view of the above, and is a prestress lining method for shield tunnel cast-in-place concrete that can easily, reliably, and efficiently introduce prestress into cast-in-place concrete and uses simple equipment, and an apparatus therefor. The purpose is to provide the following.

Means for Solving Problems 1 In accordance with the above-mentioned object, the structure of the present invention, which is summarized in the above-mentioned claims, is provided as a prestress lining construction method for cast-in-place concrete for shield tunnels in order to solve the above-mentioned problems. As a first step, after excavating a predetermined distance with the shield machine 11, the shield jack 12 and press jack 13 are shortened to create a space S in the rear of the shield machine ti, and as a second step, a space S is created in the rear part of the shield machine ti. , one side of the parallel surface of the H-shaped steel 31 is turned inside, or the horizontal surface of the T-shaped steel 31 is bent inside or outside, and there is a P between the two ends of the eldest part in one direction.
A plurality of PC steel holding ring constituent members 30a each having PC steel holding ribs 33 having notches 35 for locking C steel members 3 arranged at desired intervals, and substantially the same shape as the PC steel holding ring constituent member 30a. Assemble the formwork/PC steel retaining ring 30 with one or more PCtA material tension tightening ring constituent members 30b having a box opening 34 opening on the inner side, and as a third step, the formwork/PC steel material holding ring 30 is assembled with The PC steel material 3.3 whose ends are placed inside the box 34 is attached in a loop shape to the retaining ring 30, and as a fourth step, an inner formwork 70 is installed inside the formwork-cum-PC steel material retaining ring 30. After assembly, concrete 9 is poured into the injection site S° surrounded by the inner formwork 70 and the formwork/PC steel retaining ring 30.30, and as a fifth step, the shield jack 12 and press jack 13 are extended. In the sixth step, the concrete 9 placed at the injection site S' reaches a predetermined strength, and then the inner formwork 70 is demolded and the concrete 9 is poured into the box 34 on both sides. (One person tensions the ends of the PC steel material 3 using a tensioning jig 6 to introduce prestress into the PC steel material 3, and then connects the ends of the 20W4 material 3 to each other with a coupler in the box-out 34. A technical measure was taken in which the belt was tightened under tension at 50°.

In addition, as a prestress lining device for cast-in-place concrete for shield tunnels of the present invention, one side of the parallel surface of the H-shaped steel 31 is turned inside, or the horizontal surface of the T-shaped steel 31° is curved inside or outside, and the longitudinal sides thereof are curved. 2. A plurality of PC steel material holding ring members 30a each having a plurality of PC steel material holding ribs 33 having cutouts 35 for locking the PC steel material 3 disposed at desired intervals, and two PC steel material holding ring constituent members 30a A formwork-cum-PC steel material holding ring 3 constituted by one or more PC steel tension tightening ring constituent members 30b having a box portion 34 that is approximately the same shape as the box portion 34 and opening on the inner side.
0.

Therefore, in the construction method of the present invention, excavation is carried out by one inch in the conventionally known first step, and the formwork and PC steel retaining ring 30 assembled in the second step is attached to the PC steel material 3 installed in the third step. to secure it in place. Then, when concrete 9 is poured in the fourth step, the PC steel material 3 is directly embedded in the concrete 9. Further, when excavation is performed by the conventional method in the fifth step, the concrete 9 placed in the fourth step is mainly pressurized by the press jack 13 and press-fitted into the shield tail void, and the distance mainly in the longitudinal direction changes. That is, the concrete 9 is mainly displaced in the longitudinal direction, and partially in the circumferential direction and the radial direction of the tunnel, and the concrete 9 is displaced mainly in the longitudinal direction and partly in the circumferential direction and the radial direction of the tunnel.
The distance between the C1g4 material holding ring 30 and the new formwork/PC steel material holding ring 30 is shortened, but the PC steel material 3 locked to the formwork/PC steel material holding ring 30 is Although it moves in the longitudinal direction as it moves, it is locked in the radial direction by the notch 35 to restrict movement and maintain an accurate mounting position. And in the sixth step, PCfj! When the 4 materials 3 are tensioned with the tension jig 6,
It is possible to directly introduce prestress into the cast-in-place concrete 9, and this prestress introduced state is maintained by coupling with the coupler 50.

In addition, in the prestress lining device for shield tunnel cast-in-place concrete of the present invention, the formwork/PC steel material holding ring 30 serves both as a formwork for the construction joint of the cast-in-place concrete lining and to hold the PC steel material 3. By accurately holding and fixing the PCjg material 3 in a predetermined position in the concrete 9 to be cast in place, and pulling the PCjg material 3 embedded in the concrete 9 with tension, a jig, etc., the concrete 9 has this P.
Prestress can be directly introduced between the C steel material 3 and the PC steel material holding rib 33.

Embodiment 1 Next, an embodiment of the present invention will be described below with reference to FIGS. 1 to 21-B.

In the figure, T is a tunnel constructed by the method and equipment of the present invention, and 11 is a shield machine for excavating this tunnel.

As the shield machine 11, a conventionally known one used in the cast-in-place concrete lining method is used, and a shield jack 12 is disposed inside the rear end of the skin plate 14, and the tip of the rod of the shield jack 12 is attached to the shield jack 12. A press ring 15 is arranged, and the rear end surface of this press ring (the right end in FIGS. 10 to 19) is in contact with the front end surface of an inner formwork 70, which will be described later, and by extending this shield jack 12, the shield machine 11 Without being able to move forward. Further, a plurality of press jacks 13 are disposed on the press ring 15, and the rod tips of the press jacks 13 are arranged so as to be in contact with the tip end surface of a formwork/PC steel retaining ring 30, which will be described later.

In the construction method of the present invention, as a first step, after excavating a predetermined distance with the shield machine 11, the shield jack 12 and press jack 13 are shortened to provide a space S in the rear part of the shield machine 11.

This first step is the same as the conventional construction method, and is
l! In a state in which the excavation is interrupted after digging (for -rings), both the shield jack 12 and the press jack 13 are in an extended state. Therefore, if the shield jack 12 and press jack 13 are shortened, the shield jack 1
As the rod No. 2 moves back, the press ring 15 and the press jack 13 move back (moves to the left in Fig. 10), and the rod of the press jack 13 also moves back to enter the press jack 13, resulting in the state shown in Fig. 11, and the shield machine 11 A space S will be obtained within the rear end of.

Next, as a second step, the H-shaped steel 31 is placed in the space S.
A PC steel holding rib 33 which is curved with one side of the parallel plane of the T-shaped steel on the inside or with the horizontal plane of 31° on the inside or outside, and has a notch 35 between its longitudinal ends for locking the PC steel 3. A plurality of PC steel material holding ring constituent members 30a arranged at desired intervals, and one or more PCs having a box portion 34 that has substantially the same shape as the PC steel material holding ring constituent members 30a and opens on the inner side. The formwork/PC steel retaining ring 30 is assembled with the steel tension tightening ring component 30b.

The PC#l material holding ring component 30a and the PC steel material tension tightening ring component 30b are made of H-shaped steel 31 or T-shaped steel 31' (see Figure 3-B). If one side of the parallel surface called the flange of the section steel is set as the inside, and in the case of T-shaped steel 31゛, the horizontal surface is set as the inside or the outer (water) surface is set as the outside, the area in contact with the tail seal 14a of the shielding machine 11 will be large and high. (This is desirable because a sealing effect can be obtained) and is curved into an arc shape divided into i number parts (in the illustrated embodiment, it is divided into six parts, see FIG. 2).

Then, this PC steel material holding ring component 30a and P
P is attached to both ends of the C steel tension tightening ring component 30b.
C steel material holding and joint ribs 32, 32 are arranged. This PC steel material holding/jointing rib 32.32 is a flat steel plate fixed to the longitudinal end of the H-shaped steel 31 by welding or the like as shown in Fig. 3-C. is provided with a notch 35 for locking the PC steel material 3. Further, this PC steel material holding/joining rib 32 is not provided with holes 36 through which connecting screws (not shown) are inserted so that the ribs can be successively connected. The main purpose of this PC steel material holding/jointing rib 32 is to serve as a joint, and as shown in Figure 3-D, conventional methods such as attaching splice plates 32'32' to the vertical surface and bolting them are used. This may be replaced with a known joint mechanism.

In addition, in the case of the H-shaped steel 31, the PCW4 material holding rib 33 is fixed by welding or the like by joining its three sides to the inner surfaces of the U-shaped portions on both sides of the H-shaped steel 31, as shown in Figure 3-A. type f
In the case of J431°, as shown in FIG. 3-8, the two sides of the 31° T-shaped steel are joined to the horizontal and vertical surfaces on both sides of the vertical surface and fixed by welding or the like. Furthermore, the above-mentioned notch 35 is provided on the side part of the PC steel holding rib 33 (the same applies when using the PC steel holding and fiber holding rib 32).
If this notch 35 is made to have a size slightly larger than the diameter of the PC steel material 3, it will absorb dimensional errors and errors when forming the formwork/PC steel material retaining ring 30, and the installation of the PC steel material 3, which will be described later, will be easier. It becomes easier. Furthermore, if the notch 35 is curved into an L-shape, the PC steel material 3 can be more securely locked. In addition, in this embodiment, four PC steel material holding ring constituent members 30a and two PCw
One formwork and P with 4 materials tension fastening glue component 30b
The C steel retaining ring 30 is configured, but if it includes one or more ring components 30b for pre-stressing the PC steel material, this combination may be constructed as appropriate, such as by composing all of the ring components 30b for pre-straining the PC steel material. May be changed. In addition,
When assembling the formwork/PC steel retaining ring 30, it is easier to assemble it by moving it toward the assembly press jack 13 in the center of the space S, as shown by the chain line in FIG.

Then, as a third step, the PC steel materials 3, 3 whose ends are placed inside the box part 34 are attached to the formwork and PC steel material holding ring 30.
Attach it in a loop.

The above-mentioned PC steel material 3 is installed by being engaged with the cutout part 35 of each PC steel material holding rib 33 of the assembled formwork and PC steel material holding ring 30, and its end is inserted into the box part 34.
There are people. Also, this PC! M material 3 is one formwork and P
One or more C3H material holding rings 30 are connected on one side to form a loop, and in this embodiment, two pieces are used to form a loop as shown in FIG. There is. Note that this PC steel material 3 is temporarily connected with a coupler 50 to be described later to form a loop, and in this third step, this PC steel material 3 is used as a formwork and PC that was assembled in the second step. One side of the steel retaining ring 30 and the formwork/PC steel retaining ring 3 assembled in the pre-construction stage
It is preferable to label the other side of 0 (see Fig. 13).

Furthermore, as a fourth step, an inner formwork 70 is assembled inside the formwork/PC steel holding ring 30 described in E, and the injection site surrounded by this inner formwork 70 and the formwork/PC steel holding ring 30. Pour concrete 9 at S°.

The inner formwork 70 is of a conventionally known so-called segment type or loose center type, and the desired strength can be obtained by assembling segment pieces made of steel or the like. 9 is the initial inner formwork 70 as shown in FIGS. 14 and 15.
and the injection site S° surrounded by the formwork/PC steel holding ring 30 assembled in the second process, the formwork/PC steel holding ring 30 assembled in the previous construction stage, and the skin plate 14 of the shielding machine 11. A predetermined amount is injected from the injection lower 1 placed in the inner formwork "70".

In the fifth step, the shield machine 11 excavates while extending the shield jack 12 and press jack 13.

That is, the shield machine 11 obtains a propulsive force by the extension of the shield jack 12 and the press jack 13, moves from the state shown in FIG. 16 to the left in the same figure, and performs the following steps to reach the state shown in FIG. 17. excavate as much as possible. At this point, the concrete 9 poured into the injection site S'' in the fourth step has been adjusted so as not to solidify, so as the shield machine 11 excavates, the shield tail void, that is, the thickness of the skin plate 14 Although not shown, concrete 9 is press-fitted into the space formed by the outer excavation part of the skin plate 14, and the concrete 9 is inserted into the space formed by the inner formwork 70 and the formwork/PC steel retaining ring 30.30, which are also shown in the figure. The final pouring site is surrounded by unprotected ground.

Then, as a sixth step, after the concrete 9 poured at the final pouring site in the fifth step reaches a predetermined strength, the inner formwork 70 is demolded and the concrete 9 is poured into the box part 34 from both sides. The prestress is introduced into the PC steel material 3 by tensioning the end of the PC steel material 3 using a tensioning jig 6, and then the box portion 3 is tightened.
4, the ends of the PC steel materials 3 are tightened together with a coupler 50. In this sixth step, the fact that the concrete 9 has a predetermined strength means that it is possible to introduce prestress into the concrete 9 and that the concrete does not undergo harmful deformation even when the inner formwork 70 is demolded. That's true.

The example in Fig. 20 is an application example of the construction method of the present invention.
A PC steel retaining ring 30' made of jT type steel is placed between the C steel retaining ring 3o and the newly assembled formwork/PC steel retaining ring 30. As shown in Figures 21-A and 21-B, this PC steel retaining ring 30° uses a T-shaped steel 31'' whose vertical length is shorter than that of the formwork and PC steel retaining ring 3o. Something,
This T-shaped steel 31" is curved with the horizontal plane inward, and a plurality of PC steel holding ribs 33° having cutouts 35" for locking the PC steel material 3 are arranged at desired intervals between both ends in the longitudinal direction. It is composed of a ring component for holding a PC steel material, and one or more ring components for tension tightening of a PC steel material, each having a box portion that is approximately the same shape as the ring component for holding a PC steel material and opening on the inner side. is the same as the formwork and PCtA material holding ring 30.As shown in Fig. 26-B,
This PC steel retaining ring has a 30° notch 35"
It may also be arranged on the outer circumferential side edge of the four-material holding rib 33' (Fig. 21 top! j).

Although the PC steel retaining ring 30' does not have a formwork function, it is useful for increasing the construction speed by making the ring longer. That is, the cast-in-place lining construction method has a construction speed of about 4 to 5 rings per day, which is about half that of the conventional segment construction method, which is about 1 ring per day. Therefore, increasing the distance for this minus ring can greatly contribute to improving construction efficiency. However, if the -ring is made longer and the formwork-cum-PC steel retaining rings 3o are placed at both ends of this length, the desired prestress may not be introduced into the center. Therefore, we decided to use this PC steel retaining ring 30° as a formwork and PC.
By arranging one or more of the steel retaining rings 3o and 30 at the intermediate portion, the desired prestress can be introduced.

The tensioning jig 6 used in this sixth step has the construction shown in FIGS. 4 and 5. That is, this tension jig 6 is composed of a pair of yokes 61.61, a tension rod 62, a jack 63, and a nut 64.64.

As shown most clearly in FIG. 5, the yoke 61 has an insertion hole 6 in the center through which a tension rod 62 is inserted so as to be freely removable.
5 has grooves 66 and 66 on both sides for inserting and locking the PC steel material 3. One side of this yoke 61.61 is PC
A PC steel material 3.3 is inserted into the groove 66, 66 at one end side of a coupler 50 (to be described later) that connects the ends of the steel materials 3 to each other, and the other PC steel material 3.3 is placed on the opposite side of the coupler 50. The PC steel material 3.3 is also placed in the groove 66.66 in front of the nut 64.64 which is screwed in the middle of the PC steel material 3.3. The tension rod 62 inserted through the insertion holes 65.65 of both yokes 61.61 has one end locked to the outer surface of one yoke 61 with the locking head 62a, and the other end is locked to the outer surface of the other yoke 61.
It is connected to a center hole type jack 63 arranged on the outside of 1. A conventional jack 63 can be used, and the amount of protrusion can be changed by screwing the tension rod 62 back and forth.
When the protrusion amount of the tension rod 62 is reduced, both yokes 61.61
The distance between is reduced and the PC steel material 3.3 is now under tension. Note that the grooves 66 and 66 are for detachably inserting the yoke 61 into three parts of the PC steel material,
Both PC steel materials 3 stretched in parallel with appropriate groove depths set
．． 3, the groove 66 may be arranged on the lower surface of the yoke 61.

Further, the tensioning jig 6 may have a structure shown in FIG. 8 or 9.

The example in FIG. 8 uses a cylinder jack 63'' instead of the center hole jack 63. In this case, the insertion holes 65 are provided oppositely in the left and right parts of both yokes 61 and 61 instead of in the center. , a pair of tension rods 62° passed through both yokes 61, and the tips of 62° are connected to a plate 66 disposed outside the jack 63°. In the example shown in FIG. 8, a rope 62'' is used instead of the tension rod 62, and this rope 62'' is looped around the yoke 61 on one side and the tip of the cylinder rod of the jack 63°. In addition,
It is a good idea to use a high-strength material such as aramid fiber as the material for the rope 62''.

Further, the coupler 50 used in the sixth step is
A configuration as shown in FIG. 7 and FIG. 7 is used.

This coupler 50 temporarily connects both PC steel materials 3 in the third step so as to cope with fluctuations in their mutual positional relationship, and after the completion of the sixth step, both PC steel materials 3 are connected and tightened in a tensioned state. 51 is a cylindrical main body, and this main body 5
1 has a through hole 52 in the center for loosely inserting the 20W4 material 3 at both ends thereof, and a ball receiving surface 56 on the inside.
No. 3 can be screwed together. and,
The left and right PCs connected by this coupler 50
The steel material 3 has a thread on the outer periphery of its tip, and the PC steel material 3 on the other side on the left and right side has a thread in the opposite direction on the outer periphery of its tip. They are inserted through the through holes 52, and nuts 55 having spherical portions 54 are screwed onto the ends protruding from the through holes 52, respectively. Therefore, when the F recording seat body 53°53 is screwed onto both ends of the main body 51, both P
C steel material 3 can be connected, and this l12 said nut 5
5° 55 is movable toward the center of the main body 51, so both the PC steel members 3.3 move toward the center of the main body 51. In other words, when tensioning the PC steel members 3, the PC steel members 3. It is possible to shorten the distance between the ends of the In addition, in this coupler 50, the spherical part 55 can slide on the seat body 531, and there is a gap between the PC steel material 3 and the through hole 52, so that the angle between the PC@material 3 and the main body 51 is can be changed within a predetermined range, thereby absorbing errors in the mounting position of the PCj14 material 3. The inner surface 56 of the main body 51 has a hollow cross-sectional shape into which the nut 55 is loosely fitted, as shown most clearly in FIG. By advancing the PC steel members 3.3, both PC steel members 3.3 can be tensioned and fixed to the center side of the main body 51 in a so-called turnbuckle manner.

In addition, in the construction method of the present invention, the coupler 50 can be attached to a screw thread on the outer periphery of a conventionally known anchor and the tip of the PC steel material through which the anchor is inserted, as long as it does not interfere with the tensioning of the tensioning jig 6. It may be changed to an anchor bolt or the like that is screwed together.

Effects of the Invention Since the shield tunnel prestress cast-in-place concrete lining construction method device of the present invention is as described above, it is possible to sequentially introduce prestress into the cast-in-place concrete of the shield tunnel, and to create a prestressed concrete lining with a predetermined resistance. Stressed concrete lining can be easily and reliably constructed.

In particular, in the construction method of the present invention, the PC steel material holding ring component 30 has a unique configuration in the second step compared to the conventional process.
using a formwork/PC steel material holding ring 30 consisting of a and a ring component 30b for tension tightening the PC steel material, mounting the PC steel material 3 on the formwork/PC steel material holding ring 30 in a second step; The shield tunnel prestress cast-in-place concrete lining construction method does not require a large increase in work volume, since the previously established shield tunnel cast-in-place concrete lining construction method can be used except for tightening the PC steel material 3 in six steps. This is something that can be provided.

Further, in the tunnel completed by the method of the present invention, the concrete lining is structurally integral in the circumferential direction, so that a tunnel with high strength and excellent water-stopping properties can be obtained. However, the concrete lining has a construction joint in the longitudinal direction at 30 parts of the formwork and PC steel retaining ring;
There is no problem with strength because the connection is relatively strong with the C steel material retaining ring 30, and since the concrete 9 and the formwork/PC steel material retaining ring 30 are in close contact, it is more watertight than the segment type butt. It is excellent.

In addition, the device of the present invention is installed on one side of the parallel surface of the H-shaped steel 31 or on the T
The horizontal surface of the shaped steel 31' is curved on the inside or outside, and on both ends thereof there are provided PC steel holding/joining ribs 32 and 32 having notches 35 for locking the PC steel 3, and both PC steel holding/joining ribs. Between them are a plurality of PC steel holding ring constituent members 30a in which PC steel holding ribs 33 having cutouts 35 for locking the same PC steel material 3 are arranged at desired intervals, and the PC steel holding ring structure. This is because it has a formwork/PC steel retaining ring 30 which is composed of one or more PC steel tension tightening ring constituent members 30b each having a box portion 34 that has substantially the same shape as the member 30a and opens on the inner side. , P which is a component of the formwork and PC steel retaining ring 30
The ring component 30a for holding the C steel material and the ring component 30b for tension-fastening the PC steel material may be formed by bending commercially available steel shapes and can be produced at low cost. Also,
This formwork-cum-PC steel retaining ring 30 has excellent workability because the PC steel 3 can be attached to it after assembly, and in particular, it does not require construction-related problems such as shear transmission bars in conventional construction methods.

Further, in both the method of the present invention and the device of the present invention, the prestressing steel material 3 can be buried at an accurate position in the radial direction of the tunnel, so that ideal prestress can be introduced from the viewpoint of structural mechanics.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIGS. 1 and 2 are cross-sectional views of a tunnel completed using the method of the present invention, FIG. 3-A is a cross-sectional view taken along A-A, and FIG. 3-B is a T A when using shaped steel
-A sectional view, Figure 3-C is a partial perspective view of the ring component for holding the formwork and PC steel material, and Figure 3-C is a partial perspective view of the ring component for holding the PC steel material in another embodiment. , Fig. 4 is a partially cutaway bottom view of the ring component for tension tightening of PC steel material,
Figure 5 is a perspective view of the yoke, Figure 6 is a sectional view of the coupler,
FIG. 7 is a sectional view taken along line B-B, FIGS. 8 and 9 are plan views of tensioning jigs in different embodiments from FIG. 4, and FIGS. 10 to 19 explain each process. Figure 20 is a cross-sectional view of the tunnel completed by the method applying the present invention, Figures 21-A and 21-B are the formwork and 20w4 material holding material used in the applied example of the present invention. A cross-sectional view of the ring, and Figure 22 and subsequent figures show a conventional example. Figure 22 is a partial cross-sectional view of a conventional prestressed concrete cylindrical tank, and Figure 23 is a perspective view of precast concrete used in the conventional example. FIG. 24 is a sectional view of the main parts including a tensioning jig for bringing the precast concrete PC steel into a tensioned state;
FIG. 25 is a perspective view of a main part showing another conventional example, and FIG. 26 is a perspective view of a main part showing still another conventional example.

Claims (2)

[Claims] (1) As a first step, after digging a predetermined distance with the shield machine 11, shorten the shield jack 12 and breath jack 13 to create a space S in the rear of the shield machine 11, and as a second step, S is curved with one side of the parallel surface of the H-shaped steel 31 inward, or with the horizontal surface of the T-shaped steel 31' inward or outward, and there is a PC between both ends in the longitudinal direction.
A plurality of PC steel retaining ring constituent members 30a each having PC steel retaining ribs 33 having notches 35 for locking the steel members 3 arranged at desired intervals, and substantially the same shape as the PC steel retaining ring constituent member 30a. One or more PC steel tension tightening ring components 30 having a box portion 34 opening on the inner side
Assemble the formwork/PC steel material holding ring 30 with b, and as a third step, the PC steel material 3, 3 whose ends penetrate into the box part 34 are attached to the formwork/PC steel material holding ring 30 in a loop shape. As a fourth step, an inner formwork 70 is assembled inside the formwork/PC steel material holding ring 30, and an injection site S' surrounded by this inner formwork 70 and the formwork/PC steel material holding rings 30, 30 is formed. As a fifth step, the shield jack 12 and press jack 13 are extended and the shield machine 11 excavates, and as a sixth step, the concrete 9 poured at the injection site S' is placed in a predetermined position. After reaching the strength of A prestress lining construction method for cast-in-place concrete for shield tunnels, characterized in that the ends of the prestressed steel members 3 are tightened together with couplers 50 within the box part 34. (2) A notch 35 which is curved with one side of the parallel surface of the H-shaped steel 31 inward or with the horizontal surface of the T-shaped steel 31' inward or outward, and between both ends in the longitudinal direction is a notch 35 for locking the PC steel material 3.
A plurality of ring constituent members 30a for holding PC steel material, each having PC steel material holding ribs 33 arranged at desired intervals;
It has a formwork-cum-PC steel holding ring 30 which is composed of a steel holding ring constituent member 30a and one or more PC steel tension tightening ring constituent members 30b having box parts 34 that are approximately the same in shape and open on the inner side. Prestress lining equipment for cast-in-place concrete for shield tunnels.