JPH0631553B2 - Shield excavation method and shield excavator for implementing this method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is intended to carry out a shield digging method and a method of applying a cast-in-place lining shield construction method, which is performed while directly placing concrete in the tail portion of the shield digging machine and performing lining. Of the shield machine.

The so-called non-segment construction method, in which lining work is performed without using segments, is known in various ways. In this construction method, when excavating a tunnel while constructing cast-in-place concrete lining, the shield machine is propelled by some means from the already hardened part of the lining concrete by the jack fixed to the machine. It was common to do so with the reaction force.

In the method of propulsion of this shield machine, since the fresh concrete is located between the shield machine and the already hardened lining concrete, the jack should be used when the propulsion reaction force is obtained from this lining concrete. A means for transmitting this propulsion reaction force is necessary. Various methods are known as this means, but the main methods are as follows: 1) Push rod type, in which rods continuously buried in the lining concrete are intervened, and 2) already hardened lining concrete. Until it reaches the internal formwork, which is carried out through the internal formwork that has been built in continuously, 3) Pressing the freshly cast concrete with a jack to accelerate the hardening, and through the press ring that abuts against this. There is a press ring type.

However, these modes have the following drawbacks.

First, in the push rod type, since the rod does not buckle when a compressive force is applied to the rod, the rod cross section becomes large, it becomes difficult to handle, and it is costly and economically disadvantageous. Further, when a large load required to propel the shield machine is applied to the rod, the rod is displaced, which may adversely affect the quality of the placed concrete. Moreover, some measures are needed to fill the tail voids.

Next, in the method using the inner mold, some measure is required to fill the tail void.

Further, in the press ring system, it is difficult to control the uniform pressing by the jacks over the entire circumference of the press ring, and the reaction force for excavation changes with changes in the state of the shield face, so the pressure applied to the fresh concrete is It cannot be kept constant over time. As a result, the quality of the poured concrete becomes uneven, which is a problem in terms of concrete quality.

The present invention provides a tunnel excavation method and excavation device using cast-in-place concrete lining, without the above-mentioned drawbacks and without performing secondary lining using an expensive lining material segment. That is.

According to the present invention, according to the present invention, concrete is highly placed by a high-pressure pump in a void formed by a ground around a tunnel formed by excavation of a shield and an inner formwork built in a ring and an existing concrete lining. While pouring concrete by press fitting with pressure, the pouring pressure of the pouring concrete generated in the closed void at that time is taken as a reaction force, and this reaction force is the end formwork formed in the shield tail part. It is solved by transmitting it to the machine and propelling the machine.

Further, in the method according to the present invention, the lining concrete is poured by using a high-pressure concrete pump to press the concrete between the ground around the tunnel and the inner formwork built in a ring and into the voids of the existing concrete lining. By applying a certain pressure to the placed fresh concrete,
While compacting, concrete is pushed into the tail void to eliminate voids.

In carrying out the above method, in order to more securely control the direction of the shield machine and additionally assist the propulsion, in the method according to the present invention, the end form of the skin plate and the inner ring are installed in an annular shape. While pouring concrete by pouring concrete with a high pouring pressure by a high-pressure pump into the air space formed between the formwork, the surrounding ground and the existing concrete lining, it occurs in the closed void at that time The direction of the shield machine is controlled while taking the pouring pressure of the concrete as reaction force and transmitting this reaction force to the machine through the end form formed in the shield tail to propel the machine. When doing so, insert a steel rod appropriately buried on the circumference of the lined concrete into the center pole jack provided on the tail part of the shield machine and firmly grip the steel rod in the bending direction. The braking force is formed by, thereby performing a manner the direction control so that only the site which is not gripped turns the direction to promote, it is possible to control the direction of the shield machine regardless aspects of the natural ground.

Since the force required for propelling the shield machine is 70 to 130 tf / m ² per unit area of cutting face (tunnel standard specification edited by the Japan Society of Civil Engineers) from the experience so far, the shield machine accompanying the concrete press fitting of the method according to the present invention The propulsion of the machine is based on the following formula: (In the above formula, P is the concrete placing pressure (t / m ² ), D is the outer diameter (m) of the shield machine, and d is the inner diameter of the lining concrete.
It has been found that the shield machine can be propelled when concrete is placed with a pressure commensurate with the soil quality of the face with the upper limit of the pressure P (t / m ² ) shown in (m)). by.

The shield machine according to the invention for carrying out the method is characterized in that the end of the shield tail is provided with a mounting opening for a concrete delivery conduit for concrete pouring. The formwork 10 is rigidly contacted in the radial direction with respect to the tunnel axis, and the inner formwork is built with a packing interposed between the end formwork for concrete pouring and the inner formwork for the tunnel lining, and one-sided shield A high-pressure concrete pump was installed inside the excavator, and a concrete delivery conduit for concrete pouring of this high-pressure concrete pump was provided so as to open into the void through the above-mentioned mounting opening of the end-form for concrete pouring. That is.

Further, the characteristic feature of the shield machine for carrying out the method according to the present invention is that the end of the shield tail portion is provided with a mounting opening for a concrete delivery conduit for concrete placement. The end formwork is rigidly contacted in the radial direction with respect to the tunnel axis, and the inner formwork is erected by packing between the end formwork for concrete pouring and the inner formwork for the tunnel lining, and one-sided shield A high-pressure concrete pump is installed on the abutment inside the excavator, and the concrete delivery conduit for concrete pouring of this high-pressure concrete pump is inserted through the above-mentioned mounting opening of the concrete pouring end formwork inside the shield machine. It is provided so as to open in the air space.

Further, the characteristic feature of the shield machine for carrying out the method according to the present invention is that it is embedded in the existing lining in the previous step and is fixed by being extended and fixed following the construction of the inner formwork. The center hole type jack for gripping the steel rod and exerting a braking action to control the direction is provided inside the concrete end casting form fixed to the end of the shield skin plate.

With the above-described excavation method and shield machine according to the present invention, it is possible to continuously excavate a tunnel by an extremely simple method and without requiring a large equipment cost.

Further, according to the present invention, a center hole type jack in which a steel rod, for example, a PC-steel rod or a wire rope laid between the surrounding ground and the inner formwork is attached to an end formwork fixed to the inner circumference of the skin plate. By performing the braking operation with, it becomes possible to easily control the direction of the shield machine.

Hereinafter, the present invention will be described in detail with reference to the embodiments illustrated in the accompanying drawings.

FIG. 1 is a sectional view showing a shield excavator body A according to the present invention in a state of excavation. The excavator body A is composed of a shield skin portion 1 and a shield tail portion 8 each having a cutter on the face side corresponding to the structure of a normal shield, for example, a mechanical shield. In the shield tail portion 8 of the extension of the shield skin portion 1, an end formwork 10 for concrete pouring is rigidly welded to the inside of the tunnel in the immediate vicinity of the inner formwork 5.

As shown in FIG. 5, packing 12 is inserted between the end of the end form 10 for concrete pouring and the inner form 5, and the surrounding ground B and the inner form 5 are inserted. The air space between and is sealed from the inside of the shield machine main body A.

The end formwork 10 for pouring concrete is provided with an opening for passing a conduit 3 for pumping concrete for pouring. Therefore, the conduit 3 is open in the space between the peripheral ground B and the inner mold 5 in the end mold 10 for pouring concrete.

At the center of the internal air space C of the shield machine body A,
As is clear from the cross section shown in the figure, a high-pressure concrete pump 9 is installed on the abutment 11 and from this high-pressure concrete pump 9, the concrete pressure-feeding conduit 3 for lining concrete placement is connected to the radius of the shield machine. Guided with appropriate spacing in the direction, this conduit 3 terminates in an opening formed in the end casting 10 for concrete pouring.

The inner formwork 5 is a normal connecting formwork, and is removed from the lining concrete part that is sequentially hardened as the digging progresses and is built in the direction ahead of the digging direction, but as shown in FIG. Since the machine moves forward while excavating the face, it is advantageous that the number of molds is increased by D or more for one mold in the direction of excavation.

As can be seen from FIG. 1, the excavation is carried out, for example, by a full-section excavator, and as the excavation progresses, concrete 4 is placed in the air space 4 ′ formed in the inner formwork 5 and the surrounding ground B. The lining 6 is formed. At this time, this concrete is pressurized from the high-pressure concrete pump 9 through the concrete pressure-feeding conduit 3 for placing the lining concrete,
That is, since the concrete 4 which has been press-fitted into the space 4'is filled with the pressure adapted to the above equation, the concrete 4 works to propel the shield machine A forward after the space 4'is filled. Further, due to this pressure, the concrete itself receives a pressurizing action to form a dense lining 6 in the air space 4 '.

As can be seen from Fig. 2, in the existing lining of the air space 4'between the surrounding ground B and the inner formwork 5, the steel rods 7, for example PC steel rods, are previously arranged at appropriate intervals on the peripheral surface of the excavation tunnel. The steel rod 7 is embedded and is guided by being extended by connecting with a screw or the like (not shown). This steel rod 7 penetrates the end formwork 10 for concrete pouring at an intermediate position of the concrete pumping pipe 3 for lining concrete pouring,
In addition, when the direction is controlled by the center hole type jack 23 provided inside the shield machine main body A in the end formwork 10 for concrete pouring, it is gripped to brake the shield, and when the braking action is not performed. Is guided to slide freely. A lining is formed and the steel rod 7 is embedded as it is in the inside thereof, and also serves as a support for the lining concrete.

On the other hand, the steel rod 7 essentially serves to control the direction of the shield machine A. That is, the direction control of the shield is performed by the steel rod 7 and the center hole type jack, and any one of the center hole type jacks 23 is appropriately distributed on the peripheral surface in the entire circumferential direction to be turned. Is operated by grasping the corresponding steel rod 7 and either of them is held open without exerting a grasping force.

The construction method of the method according to the present invention will be described below.

As the concrete for construction, for example, a delay type early-strength concrete is used, and this concrete is pressed from the high-pressure concrete pump 9 through the concrete pressure-feeding conduit 3 for placing the lining concrete at a pressure corresponding to the above calculated value. For example, when the shield machine is propelled in the direction of the face at a speed of 3 cm / minute, it takes time for the cast concrete to set. Therefore, in the method according to the present invention, the concrete starts to set. It takes 2 to 3 hours to do so, and the excavation amount during this period is 4 to 5 m. This is calculated from the calculation formula described below, that is, (2 to 3) hours × 3 cm / min = 3.6 to 5.4 m, and is a general numerical value as long as the construction ground has no peculiar property.

The lining which is wound up by such a method has a pouring seam interval of 4 to 5 m as compared with the conventional construction method, and therefore the water stopping property is improved. Further, as in the case of other construction methods, the concrete is subjected to a pressure action during concrete pouring, so that tail voids do not occur and ground subsidence does not occur.

Furthermore, it was confirmed that the advantage that the concrete is homogenized when the concrete is pressed under pressure is obtained.

Furthermore, when the concrete that has not yet solidified is pressed, the compressive force acting on the concrete is high only in the region near the pressing point, and sharply decreases beyond that point, so continuous pouring work is also possible.

In this case, in addition to the advantages of the intermittent lining work described above, no seam is produced, so that the waterproofness and homogeneity are improved as compared with the conventional method.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a shield machine for carrying out the method according to the present invention, taken along the tunnel axis, and FIG. 2 is a view showing a steel rod and a center-hole type jack with the cross section changed from that of FIG. 3 is a tunnel cross-sectional view taken along the section line AA of FIG. 2, FIG. 4 is a tunnel cross-sectional view taken along the section line AA of FIG. 1, and FIG. 5 is shown in FIG. The enlarged view of the position S. The symbols in the figure are: 1 ... shield machine main body 3 ... concrete delivery pipe for concrete placement 4 ... cast concrete 5 ... inner formwork for tunnel lining 6 ... finished lining 7 ... steel rod 8 …… Shield tail 9 …… High-pressure concrete pump 10 …… End formwork for concrete placement 11 …… Abutment 12 …… Packing 23 …… Center hole type jack A …… Shield body B …… Ground C …… Air space inside the shield D …… Inside mold at the top

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 61-172997 (JP, A) JP 60-126496 (JP, A) JP 60-123700 (JP, A)

Claims (5)

[Claims] 1. A shield excavation method applying a cast-in-place lining shield construction method in which concrete is directly placed in the tail portion of a shield excavator while a lining is being constructed, and a ground around a tunnel formed by excavating a shield. While pouring concrete by press-fitting concrete with a high pouring pressure by a high-pressure pump into the void formed between the inner formwork built in and the ring and the existing concrete lining, it was closed at that time. It is characterized in that the pouring pressure of the pouring concrete generated in the void is taken as a reaction force, and this reaction force is transmitted to the excavator through the end formwork formed in the shield tail portion to propel the excavator. , The above shield digging method. 2. The lining concrete is placed by pouring concrete with a high-pressure concrete pump between the ground around the tunnel and the inner formwork built in a ring and into the voids of the existing concrete lining. The shield excavation method according to claim 1, wherein a constant pressure is applied to the fresh concrete to compact it and the concrete is pushed into the tail void to eliminate voids. 3. A shield excavation method applying a cast-in-place lining shield construction method, in which concrete is directly placed in the tail part of the shield excavator while a lining is applied, and the shield plate is constructed annularly with the end formwork of the skin plate. While the concrete was being placed by pouring the concrete into the air space formed by the embedded inner formwork, the surrounding ground and the existing concrete lining with a high placing pressure using a high-pressure pump, it was closed at that time. While taking the pouring pressure of the pouring concrete generated in the void as a reaction force, this reaction force is transmitted to the excavator through the end formwork formed in the shield tail portion and the excavator is propelled while the shield machine is propelled. To control the direction of the lining, a steel rod appropriately buried on the circumference of the lined concrete is internally routed to the center pole jack provided on the tail part of the shield machine. Thereby, bending the braking force is formed by firmly gripping the steel rod in the direction, performs direction control so as to turn the direction only sites that are not gripped to promote, the shield method. 4. A cast-in-place lining shield construction method in which concrete is placed between the end formwork of the shield machine and the inner formwork built in a ring shape and in the gap of the existing concrete lining while the lining work is performed. In order to carry out the shield excavation method performed by using, a mounting opening (21) for the concrete delivery conduit (3) for concrete placement is provided at the end of the shield tail (8) in the shield excavator. The end formwork for concrete pouring (10) is rigidly contacted in the radial direction with respect to the tunnel axis, and between the end formwork for concrete pouring (10) and the inner formwork for tunnel lining (5). The inner formwork (5) is built with the packing (12) in between, and the high-pressure concrete pump (9) and the abutment (11) are installed inside the shield machine, and this high-pressure concrete pump (9) Concrete delivery conduits for concrete pouring (3)設用 end formwork
The shield machine, wherein the shield machine is provided so as to open into the air space (4 ') through the mounting opening (21) of (10). 5. A steel rod (7) which is embedded in an existing lining in the previous step and which is extended and fixed following the erection of the inner formwork is gripped to exert a braking action and direction control. The shield machine as described above, characterized in that the center hole type jack (23) for performing the above is provided inside the end formwork (10) for concrete pouring fixed to the end of the shield skin plate.