JP2004316318A - Arrival section structure of arrival shaft and arrival method for shield machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arrival section structure of an arrival shaft and an arrival method for a shield machine capable of safely arriving at a shaft so that the shield machine for advancing a hole in the ground does not give an influence on the peripheral ground of the arrival shaft. <P>SOLUTION: A through-hole 4 is bored in a wall in an arrival scheduled site of the shield machine 3 of a shaft side caisson block constructed in an edge installing position on the ground. The outside of the through-hole 4 is blocked by a temporary external wall 12, at the same time, a steel-made bulkhead 16 is detachably mounted to the inside of the wall, and a space defined by the temporary external wall 12, the wall through-hole 4 and the bulkhead 16 is used as an arrival section chamber 20. A ring tube 25 and a ring seal 26 as an annular seal section are provided on a position on a predetermined inner circumferential surface in the arrival section chamber 20 and, at the same time, the inside of the chamber 20 is filled with a stabilizing filler 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reaching part structure of a reaching shaft and a method of reaching a shield excavator to the same shaft, and allows a shield excavator that has excavated in the ground to safely reach the shaft so as not to affect the ground around the reaching shaft. The present invention relates to a reaching portion structure of a reaching shaft and a method of reaching a shield excavator for making the shaft reach.
[0002]
[Prior art]
Conventionally, in tunnel excavation work using a shield excavator, the ground around the arrival shaft, which is the end point of the excavation section, has been used to secure the surrounding ground when removing the wall of the part necessary for reaching and penetrating the shield excavator, In order to prevent flooding when the excavator penetrates into the shaft, ground improvement was required in a predetermined area around the shaft. When the shield excavator reaches a conventional shaft where the inside of the shaft is not pressurized, the mud pressure and mud pressure on the shield surface of the shield excavator must be reduced when the wall is removed after the shield excavator arrives. It must be reduced to the same atmospheric pressure as in the shaft. In addition, when the shield excavator penetrates into the shaft, the clearance between the shield excavator and the ground improvement and the ground improvement damage until the shield excavator reaches the entrance packing through the removed wall. There was also a risk that water would flow inside and the ground around the reaching shaft would sink.
[0003]
On the other hand, the applicant has proposed a technique using a temporary wall body that can be cut with the cutter of the shield excavator in the part where the shield excavator penetrates in the starting or reaching shaft, without making the ground improvement around the shaft. (See Patent Document 1). In addition, as a technology to prevent the shield excavator from flooding into the shaft when penetrating, causing damage to the shaft and sinking of the ground around the reaching part, a reach box that can accommodate the entire shield excavator at the bottom of the shaft is used. A technique has also been proposed in which a shield excavator is installed in such a way that when the shield excavator reaches the shaft, water is filled in the reaching box and the shield excavator penetrates the box placed under a predetermined pressure (Patent Reference 2).
[0004]
In the technique disclosed in Patent Document 1, a fiber-reinforced resin rod is disposed in place of a conventional reinforcing bar in a concrete wall formed in close contact with two rows, and shield excavation is performed when the shield excavator reaches a shaft. The concrete wall is cut and penetrated by the cutter of the machine. In the technique disclosed in Patent Literature 2, a reaching box large enough to accommodate the entire shield excavator is provided in a shaft.
[0005]
[Patent Document 1]
See the description of the lower right (i) on page 2 of Japanese Patent No. 2662572.
[Patent Document 2]
See JP-A-6-42288, page 2, [0007].
[0006]
[Problems to be solved by the invention]
By the way, when the above-mentioned fiber reinforced resin rod is used, one side of a shaft structure where the entire frame is usually constructed of reinforced concrete is constructed by the fiber reinforced resin rod and a column wall reinforced with reinforcing bars. This requires a special structural design as a composite structure composed of different types of structures, and also requires simultaneous work of different types of construction. For this reason, in addition to the complexity of the process, it is expected that the work cost will increase in terms of materials and equipment. In addition, since it is necessary to reduce the pressure near the cutter in front of the shield excavator immediately before penetrating the shaft, there is a risk that water will flow into the shaft when penetrating, and the ground near the reaching part will sink, as in the case of conventional non-pressurized shafts. Was.
[0007]
On the other hand, in the vertical shaft with the arrival box, it is necessary to supply a stable liquid to the box in order to pressurize the inside of the box in addition to constructing a large volume box, and to provide equipment that can adjust the pressure. There is a problem that the cost and construction cost increase.
[0008]
Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technology, and to form a space capable of accommodating a shield excavator in a part of the shaft body, and to fill this space with a stabilizing liquid or the like for stabilization. It is an object of the present invention to provide a reaching shaft structure of a reaching shaft and a method of reaching the shield excavator that allow a shield excavator to safely reach a shaft while being filled with materials.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention forms a through hole in a wall of a shaft excavator to be reached by a shaft excavator of a shaft shaft side caisson block constructed at a cutting edge installation position on the ground, and an outer surface of the through hole. Is closed by a temporary outer wall, and a bulkhead is detachably attached to the inner surface, a space defined by the temporary outer wall and the bulkhead is defined as a reaching chamber, and at a predetermined inner peripheral surface position in the reaching chamber. An annular seal member is provided, and the inside of the chamber is filled with a stabilizing filler.
[0010]
Further, as another invention, a through hole is formed in a wall of a site where the shield excavator of the shaft excavator of the shaft shaft side caisson block constructed at the cutting edge installation position on the ground is to be reached, and the through hole is closed with a temporary outer wall, A cylindrical body is connected to the inner surface, a bulkhead is detachably attached to an end surface of the cylindrical body, the temporary outer wall, the cylindrical body, a space defined by the bulkhead is defined as a reaching chamber, and the inside of the reaching chamber is defined as a reaching chamber. An annular seal member is provided at a predetermined inner peripheral surface position, and the chamber is filled with a stabilizing filler.
[0011]
In the above-described invention, by providing the reaching part chamber with the hydraulic communication means with the outside of the shaft, it becomes possible to stably apply the same water pressure as the outside inside the reaching part chamber, and to the temporary outer wall together with the stabilizing filler. The working soil pressure can be balanced. When a force higher than the water pressure acts on the outer wall by the check valve, the same force can be held in the chamber. For this reason, the same force acts on the inside and outside of the temporary outer wall, and it is not necessary to use a structural member such as a reinforcing bar for the temporary wall, and it is possible to use a mortar material or the like that is easy to cut by a shield excavator.
[0012]
In addition, the shield excavator is brought close to the outer side of the reaching portion of the reaching shaft which has been sunk to the reaching depth of the shield excavator, and the temporary outer wall is cut while the internal and external pressures acting on the temporary outer wall are balanced. The shield excavator is made to penetrate the shaft, and after a part of the shell of the shield excavator passes through the annular seal member, the annular seal member is operated to partition the chamber space around the shell, and the shield excavator A method of arriving at the shield excavator in which the pressurizing of the cutter head is released, the filler for stabilization between the bulkhead and the bulkhead is removed, and the shield excavator is housed in the shaft by removing the bulkhead. And
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a reaching part structure of a reaching shaft and a method of a shield excavator reaching the reaching part structure according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall view showing a state in which a bottom of a reaching shaft 1 of the present invention and a shield excavator 3 that has excavated in the ground have approached a reaching portion 2 of the reaching shaft 1. The reaching shaft 1 is an underground structure in which a caisson made of reinforced concrete or the like is sunk to a predetermined depth in the ground as shown in the figure, and a concrete body of a portion facing a shield excavator 3 approaching from the side is provided. The box is removed, and the reaching portion structure 10 is incorporated in the through hole 4.
[0014]
FIG. 2 is a cross-sectional view showing one embodiment of the reaching portion structure 10. As shown in FIG. The through hole 4 has a cylindrical shape with an inner diameter slightly larger than the outer shell diameter of the shield excavator 3 to be reached. At the position of the cutting edge installation on the ground, a cylindrical through hole 4 was formed in a part of the concrete wall body 11 by using a predetermined boxless formwork when assembling the body formwork for constructing the vertical caisson block. Things. In the present embodiment, the thickness of the concrete wall 11 at the bottom of the caisson is 2 to 3 m, and a temporary outer wall 12 having a thickness of 0.2 to 0.5 m is formed on the outer peripheral surface 11a of the through hole 4. 4 is closed. The temporary outer wall 12 is formed by casting unstripped low-strength mortar (assuming a strength of about 100 to 300 N / mm ² ). The mortar having such a strength can be cut by the cutter operation of the shield excavator 3. is there. Short reinforcing bars 15 are arranged between the temporary outer wall 12 and the opening edge 11b of the concrete wall body 11, and are reinforced by shearing so as to resist out-of-plane loads. As a material for forming the temporary outer wall 12, mortar, concrete, a resin plate, or the like can be used as a material that can be easily cut by the excavation of the shield excavator.
[0015]
On the other hand, the inner peripheral surface side 11c of the through hole 4 is covered with a steel bulkhead. As shown in FIG. 2, the steel bulkhead 16 is a disk having a diameter larger than a circular hole (through hole 4) formed in the concrete wall body 11 and having a predetermined overlapping portion at an opening edge 11d. This is a steel plate processed product in which the face plate is reinforced by a stiffening member such as a shaped steel so as to have a shape or a square, and to be able to withstand the internal pressure of a stabilizing liquid or the like described later. The steel bulkhead 16 is fixed to the inner peripheral surface of the concrete wall 11 by anchor bolts 17 provided along the opening edge 11d. At this time, a ring-shaped packing 18 is interposed between the steel bulkhead 16 and the concrete wall 11 to prevent leakage of a stabilizing liquid described later.
[0016]
In this way, the reaching chamber as a space is defined by partitioning the concrete wall 11 of the shaft-side caisson block by the temporary outer wall 12 and the steel bulkhead 16. The inside of the reaching portion chamber 20 is preferably filled with a stabilizing filler 21 such as a stable liquid, a stable processing material, a stable viscous material, and a stable viscoplastic material. It is necessary that these fillers 21 function so as to achieve an internal pressure effect that balances the external pressure acting on the temporary outer wall 12 when the vertical shaft caisson block is settled or installed at a predetermined depth. As one of the means, in the present embodiment, a communication pipe 22 for communicating the inside of the reaching portion chamber 20 with the outside of the caisson block is provided. The communication pipe 22 is provided with a check valve 28 for controlling water flow. In the case where the outside of the shaft is a pressurized water zone sandwiched by a viscous soil layer due to the action of the communication pipe 22, the communication between the external pressurized water and the inside of the reaching portion chamber 20 causes the liquid in the reaching portion chamber 20 to communicate. The pressure and the pore water pressure can be balanced, and the effect of the external water pressure on the temporary outer wall 12 can be canceled (see FIG. 3).
[0017]
Bentonite stabilizing liquid and muddy water are used as the stabilizing liquid filled in the reaching portion chamber 20, and granular hard foamed resin, soft foam resin, single crushed stone, sand, and a gel-like substance as a stable viscoelastic material are used as the stabilizing solid material. Various materials such as clay and aerated clay can be used alone or as a mixture as a viscoplastic body. Note that these filling materials may be mixed with a fluid that can be conveyed from a supply pipe (not shown) provided in a part of the above-described steel bulkhead 16 to fill the reaching portion chamber 20. preferable. The step of filling the reaching part chamber 20 with the filler 21 may be performed on the ground before the start of the sedimentation by providing a mechanism for sequentially balancing with the external pressure.
[0018]
Further, a ring-shaped recess 23 is formed in a part of the inner peripheral surface in the reaching portion chamber 20, and an entrance packing 24 as a sealing member is mounted in the recess 23. As shown in FIGS. 2 and 4, the entrance packing 24 is housed in the arrival chamber 20 and supplied from a pressure source (not shown) outside the chamber 20 via an air supply pipe 27. A ring tube 25 made of synthetic rubber that expands in a ring shape (donut shape) by compressed air, and a ring seal 26 made of steel wire fixed at one end to the support portion 23a so as to cover the ring tube 25. In the present embodiment, the ring seal 26 has a substantially brush-like structure similar to a tail seal mounted on the rear end of the shell of the shield excavator, and has a grease pad between steel wires densely implanted in multiple stages. To enhance the watertight effect. In addition, as the ring seal 26, a ring seal 26 made of natural rubber or synthetic rubber having a bendable fin shape can be used as appropriate. In the initial state where the shield excavator does not penetrate into the chamber 20, the ring seal 26 covers the ring tube 25 which is flat in the recess 23 as shown in FIG. Along the inner circumference. When the shield excavator 3 penetrates into the reaching portion chamber 20 from this state, when the ring tube 25 is expanded, as shown in FIG. As shown in FIG. 4B, the inside of the chamber 20 can be partitioned by the seal 26 as a boundary.
[0019]
Here, the procedure for laying down the vertical shaft caisson functioning as the reaching shaft 1 and the reaching state of the shield excavator 3 will be briefly described with reference to FIGS.
First, as shown in FIG. 5, at the cutting edge installation position on the ground at the construction position of the reaching shaft 1, the cutting edge of the bottom caisson and the bottom plate are constructed. At this time, in the assembling work of the side wall part integrally formed with the bottom slab, a boxless formwork is installed at a predetermined position on the wall surface on the side where the shield excavator 3 (FIG. 7) reaches, and the concrete is cast by the frame concrete. Build a bottom caisson block with a cylindrical hole (through hole 4). At this time, the pipes of the communication pipe 22 and the air supply pipe 27 connected to the chamber 20 are installed in advance (see FIG. 5: construction procedure S1). Then, the shaft caisson is lowered until the reaching structure 10 formed on the side reaches the tunnel depth at which the shield excavator 3 travels. This subsidence operation procedure is the same as the known caisson construction. At this time, by opening the communication pipe 22 of the arrival part chamber 20, the inside of the chamber 20 can be maintained at the same pressure as the pressure state outside the caisson at each depth. For this reason, the working pressure is balanced from inside and outside, and no bending stress is generated on the temporary outer wall 12 (see FIG. 6: construction state S2). FIG. 7 (S3) shows a state immediately before the face of the shield excavator 3 approaches the reaching portion of the shaft caisson sunk to a predetermined depth and crushes the temporary outer wall 12 of the reaching portion. From this position, as shown in (S4), the hull portion of the shield excavator 3 is excavated and penetrated into the reaching portion chamber 20.
[0020]
The operation state of the shield excavator 3 in the reaching portion structure 10 during this time will be described with reference to FIGS. In a state where the shield excavator 3 approaches the reaching portion structure 10 (FIG. 8A), the internal pressure (filler side pressure + pore water pressure) of the reaching portion chamber 20 is balanced with the soil water pressure outside the shaft via the communication pipe 22. are doing. When the inside of the chamber 20 is filled with the stabilizing liquid, the pressure can be balanced by a liquid pressure adjusting device (not shown) provided in the shaft. In this state, the temporary outer wall 12 is crushed by a cutter (not shown) of the shield excavator 3 as shown in FIGS. To penetrate. When the cutter head of the shell 3a of the shield excavator 3 has passed the position of the entrance packing 24, the ring tube 25 incorporated in the entrance packing 24 is expanded, and the tip of the ring seal 26 is attached to the surface of the shell of the shield excavator 3. Adhere. Then, the pressurization of the stabilizing filler 21 between the entrance packing 24 and the temporary outer wall 12 is released. When the filling material 21 is a stable liquid, the pressure is reduced by discharging the stable liquid from a drainage path (not shown). In the case of a solid filler, pore water is drained after the communication pipe 22 is closed. At this time, the pressure acting on the stabilizing filler 21 between the entrance packing 24 and the steel bulkhead 16 is set to be balanced with the front pressure of the cutter head of the shield excavator 3. The stabilizing liquid may be discharged in accordance with the pressure reduction in the front surface of the cutter head by the above operation. Then, if the steel bulkhead 16 is removed after the chamber 20 is emptied, the front part of the shield excavator 3 can be exposed in the chamber 20.
[0021]
Thereafter, the segments up to the inside of the shaft are assembled in accordance with the extraction of the shell of the shield excavator 3 into the shaft, and the shaft wall portion and the shield tunnel segment are connected. At this time, by filling the space between the entrance packing 24 and the temporary outer wall 12 with a sealing material, the watertightness of the shaft connection portion can be improved.
[0022]
FIG. 9 is an overall configuration diagram of a shaft including a reaching portion structure 10 in which a steel caisson is applied as the reaching shaft 1 as another invention. FIG. 10 is an enlarged cross-sectional view showing a state of pressure adjustment by the stabilizing liquid in the reaching portion chamber 20 shown in FIG. In the reaching portion chamber 20 of the present invention, a steel caisson shell has an opening formed on a temporary outer wall 12 and an inner peripheral surface thereof connected to a steel cylinder 30 constituting the chamber 20 main body and tension is applied by a PC steel rod 31. At the same time, the steel bulkhead 16 is attached so as to cover the end face of the steel cylinder 30 and constitute the reaching chamber 20. This reaching section chamber 20 is equipped with a ring seal 26 in which a ring tube 25 is incorporated and a communication pipe 22 and is filled with a filler 21 similarly to the one shown in FIG. Subsidence of the surrounding ground at the time of arrival and intrusion, flooding and the like can be similarly prevented. The depth of the chamber 20 can be increased by connecting a plurality of stages of steel cylinders 30 in series according to the scale of the shield excavator 3. Further, a precast concrete product having a similar shape may be used instead of the steel tube 30.
[0023]
【The invention's effect】
As described above, according to the present invention, there is no need to perform ground improvement on the ground around the reaching shaft, which is economical and advantageous in terms of process, and in addition, the surrounding ground when the shield excavator reaches the shaft is improved. This has the effect that sinking, flooding into the shaft, etc. can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is an overall view showing a state in which a shield excavator reaches a reaching part structure of a reaching shaft according to the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing an embodiment of a reaching part structure of a reaching shaft according to the present invention.
FIG. 3 is a schematic explanatory view showing a state of soil water pressure action in the reaching portion structure shown in FIG. 2;
FIG. 4 is a partial cross-sectional view showing a configuration of a seal member in a reaching portion chamber.
FIG. 5 is a construction state explanatory view (1) showing an installation state of a caisson for an arrival shaft.
FIG. 6 is a construction explanatory view (2) showing an installation state of a caisson for reaching shaft.
FIG. 7 is a construction state explanatory view (3) showing an installation state of a caisson for an arrival shaft.
FIG. 8 is a state explanatory view showing a state in which the reaching shaft of the shield excavator approaches the reaching chamber of the reaching shaft;
FIG. 9 is an overall view of a reaching shaft showing one embodiment of a reaching part structure as another invention.
FIG. 10 is a state explanatory view showing a penetrating state of the shield excavator in the reaching portion structure shown in FIG. 9;
[Explanation of symbols]
Reference Signs List 1 reaching shaft 2 reaching part 3 shield excavator 4 through hole 10 reaching part structure 11 concrete wall 12 temporary outer wall 16 steel bulkhead 20 reaching part chamber 22 communication pipe 24 entrance packing 25 ring tube 26 ring seal 30 steel cylinder

Claims (4)

A through-hole is formed in the wall of the shaft excavator at the site where the shield excavator is to be reached, and the outer side surface of the through-hole is closed with the temporary outer wall, and the inner surface of the wall The temporary outer wall, the wall body through-hole, and the space defined by the bulkhead are used as the reaching chamber, and an annular seal member is provided at a predetermined inner peripheral surface position in the reaching chamber. A reaching shaft structure of the reaching shaft, wherein the inside of the chamber is filled with a stabilizing filler. A through-hole is formed in the wall of the shaft excavator at the site where the shield excavator is to be reached, and the through-hole is closed by the temporary outer wall, and a cylindrical body is formed on the inner surface of the wall. And a bulkhead is detachably attached to the end surface of the cylindrical body, and a space defined by the temporary outer wall, the cylindrical body, and the bulkhead is defined as a reaching chamber, and a predetermined inner peripheral surface position in the reaching chamber is defined. An annular sealing member, and the inside of the chamber is filled with a filler for stabilization. The reaching shaft structure of the reaching shaft according to claim 1 or 2, wherein a hydraulic communication means with the outside of the shaft is provided in the reaching chamber. The shield excavator is brought close to the outer side of the reaching part of the reaching shaft according to claim 1 or 2 which has been sunk to the reaching depth of the shield excavator, and the inner and outer pressures acting on the temporary outer wall are balanced. The shield excavator is dug into the shaft while cutting the temporary outer wall, and after a part of the shell of the shield excavator passes through the annular seal member, the annular seal member is operated to operate the chamber space around the shell. To release the pressurization of the cutter head front surface of the shield excavator, remove the stabilizing filler between the bulkhead, and remove the bulkhead so that the shield excavator is housed in the shaft. A method for reaching a shield excavator, characterized in that:

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