JP7339197B2 - Shield excavator main pushing device and initial excavation method for shield excavator - Google Patents

Description

The present invention relates to a shield excavator base pushing device and an initial excavation method for a shield excavator.

When constructing tunnels for pipelines, etc., a shield excavator is used to excavate the ground at the front end of the excavator body, and the segments are assembled at the rear of the excavator body, which is repeated for each segment ring. ing.

When starting the excavator body from the starting hole, the excavator body is propelled by the main pushing jack, but the reaction force is taken through the temporary assembled segments and struts of the number of rings installed in between. , the provisional assembly segment is installed for each ring and propelled (see, for example, Patent Document 1).

JP-A-10-8877

However, the pre-assembled segments are dismantled after the segments that become part of the tunnel have been fully assembled. In addition, since the temporary assembly segments and struts are cylindrical, they hinder the passage of workers, the delivery of materials such as segments, and the discharge of cutting earth and sand. Although it is possible to dismantle only the upper portion of the temporary assembly segment first, the lower portion remains, which is an obstacle when performing work. In particular, such an inconvenience is significant when the starting hole is long in the longitudinal direction so that a long object such as a pipeline can be inserted.

SUMMARY OF THE INVENTION In view of the above points, it is an object of the present invention to provide a shield excavator pushing device and an initial excavation method for a shield excavator that can shorten and simplify the work.

A shield excavator main pushing device according to the present invention is a main pushing device that is used at the time of initial excavation of an excavator body having a propulsion jack at its rear end, and is horizontally spaced and arranged so as to move the excavator body forward. When the excavator main body is placed in the starting hole, the front-to-rear direction between the tips of the contracted starting jacks and the wall surface on the mouth side of the starting hole is provided. The excavator main body is positioned between them, and a segment constituting a part of the tunnel is located between the front end portion of the main pushing jack and the propulsion jack at the rear end portion of the excavator main body in the longitudinal direction. A maximum of two rings of temporarily assembled segments to be dismantled after being assembled are installed .

According to the shield excavator main pushing device of the present invention, when the excavator main body is arranged in the starting hole, a temporary Only a maximum of 2 rings are installed in the set segment. As a result, the number of rings of temporary segments to be dismantled after the segments are fully assembled can be reduced compared to the conventional art, so that the work can be shortened. Furthermore, since the main pushing jacks are horizontally spaced apart and the work can be performed in the space between them, it is possible to simplify the work in the vicinity of the rear of the assembled segment. In addition, it is preferable that only one ring of the temporarily assembled segment is installed between the front end of the main pushing jack and the propulsion jack at the rear end of the excavator main body in the front-rear direction.

In the shield excavator main pushing device of the present invention, it is preferable that the main pushing jack is a multistage jack.

In this case, since the main thrust jack is a multi-stage type with three or more stages, it is possible to make the stroke longer when the length of the jack is the same compared to the case of a normal two-stage jack. Become. As a result, the excavator body can be moved from the opening of the starting hole even if there are only a maximum of two temporary assembly segments between the front end of the main pushing jack and the propulsion jack at the rear end of the excavator body. It is possible to sufficiently propel forward.

Further, in the shield excavator main pushing device of the present invention, at least one of a pushing angle or a strut exists between the base end of the main pushing jack and the wall surface on the side opposite to the mouth of the starting hole in the longitudinal direction. preferably.

In this case, due to the presence of the push angle or the strut, even if there are only two rings at maximum between the front end of the main pushing jack and the propulsion jack at the rear end of the excavator main body in the longitudinal direction, the excavation is possible. It is possible to sufficiently propel the machine body forward from the mouth of the launch pit.

The initial excavation method for a shield excavator of the present invention comprises the steps of arranging at least two main pushing jacks which are horizontally spaced apart in a starting hole; arranging an excavator body having a propulsion jack at its rear end in the starting hole between the wall surface on the mouth side of the starting hole in the longitudinal direction; and extending the piston of the jack for pushing the excavator body. a step of pushing forward to excavate the ground in front of the opening of the starting hole, and a rear end portion of the excavator main body, which is the tip portion of the main pushing jack and the rear end portion of the excavator main body. a step of installing a temporary assembly segment of maximum two rings between the propulsion jack and the forward and backward direction of the excavator body; and assembling a permanently installed segment continuously to the temporary assembly segment to a portion forward of the wall surface of the opening of the starting hole , wherein the temporary assembly segment is a segment that constitutes a part of the tunnel. It is characterized by being a segment to be dismantled after being fully assembled .

According to the initial excavation method for a shield excavator of the present invention, no more than two rings of temporary assembly segments are installed between the front end of the main pushing jack and the propulsion jack at the rear end of the excavator body in the longitudinal direction. As a result, the number of rings of temporary assembled segments to be dismantled after the segments are actually assembled can be reduced compared to the conventional art, so that the work can be shortened. Furthermore, since the main pushing jacks are horizontally spaced apart and the work can be performed in the space between them, it is possible to simplify the work in the vicinity of the rear of the assembled segment.

1 is a schematic front view showing a starting method using a shield excavator including a shield excavator root pushing device according to an embodiment of the present invention; FIG. FIG. 4 is a schematic top view showing an initial excavation method using a shield excavator. FIG. 4 is a schematic front view showing a state in which the shield excavator main body is positioned in the starting hole; 4 is a flow chart showing an initial excavation method using a shield excavator according to an embodiment of the present invention;

A shield excavator 100 including a shield excavator pushing device 20 according to an embodiment of the present invention (hereinafter simply referred to as the pushing device 20) will be described with reference to FIGS. 1 and 2. FIG. The shield excavator 100 is used when constructing shield tunnels for pipelines and the like.

A starting pit A of the shield excavator 100 is formed as a vertical pit by excavating the ground B in the vertical direction. When constructing a shield tunnel for a pipeline, it is necessary to insert a long pipeline from the starting hole A after the completion of the tunnel. ing. It is preferable that the ground B in which the starting hole A is excavated is subjected to ground improvement as necessary. A wellhead concrete C is provided around the opening of the starting well A, and the wellhead concrete C is provided with a packing (not shown).

A cradle D for supporting the shield excavator 100 is provided in the starting hole A. As shown in FIG. The excavator 100 includes an excavator main body 10 and a base pushing device 20 that starts the excavator main body 10 and is used during initial excavation.

The excavator main body 10 is a main body of an excavator used when performing shield excavation, and is conventionally known. The excavator main body 10 includes a shield tube 11, a cutter head 12 for excavation, a propulsion jack 13 for propulsion, an erector (not shown) for assembling segments 31 and 32 inside the shield tube 11, and an excavated earth and sand rearward. Equipped with a soil discharge mechanism (not shown) for carrying out to the ground. A propulsion jack 13 is arranged at the rear end of the excavator body 10 .

The main pushing device 20 is composed of a plurality of, here four, main pushing jacks 21, counterpressure walls (bearing pressure walls) 22, push angles 23, struts 24, etc., which are supported by a cradle D. there is

The main pushing jacks 21 are provided horizontally spaced apart. Here, two main pushing jacks 21a are horizontally separated and supported on the cradle D, and the other two main pushing jacks 21b are supported. are supported by a support base E provided on a receiving base D so that are positioned above each of the original pushing jacks 21a. In FIG. 2, the cradle D and the support E are omitted.

The original pushing jack 21 is a hydraulic multi-stage jack having a structure in which a plurality of mutually connected different-diameter rod portions are successively accommodated on the large-diameter side. When the multistage jack is retracted, each rod is housed in the adjacent rod on the large diameter side, and the rod with the largest diameter is housed in the cylinder. become approximately equal. On the other hand, when extended, each rod portion sequentially protrudes from the adjacent rod portion on the larger diameter side. As a result, when the length of the jack is the same, a larger stroke can be obtained compared to a normal two-stage jack. Although the original pushing jack 21 is a three-stage type in the drawing, it is not limited to this, and may be a multi-stage jack of four or more stages, or may be a normal two-stage jack. .

The reaction wall 22 is provided on the opposite side of the opening of the starting hole A, that is, on the opposite side of the opening of the starting hole A, and is made of steel, for example.

The pressing angle 23 is made of a frame made of box steel or shaped steel, and has a rectangular parallelepiped shape as a whole. The push angle 23 is positioned so as to contact the reaction force wall 22 behind the main pushing jack 21 corresponding to the main pushing jack 21 spaced apart in the horizontal direction. Although two pressing angles 23 are provided so as to be continuously positioned in the front-rear direction here, one pressing angle or three or more pressing angles may be provided, and the number thereof is not limited.

The strut 24 has a cylindrical shape using a plate-shaped steel material or the like, and circular or disk-shaped connection plates are fixed to the front and rear side surfaces thereof. The struts 24 are connected to each other by bolts or the like, so that the struts 24 are arranged continuously in the front-rear direction, here, three consecutive struts, between the base end portion of the original pushing jack 21 and the push angle 23 . , are located abutting each other. The number of struts 24 is also not limited.

The base end side of each cylinder of the main pushing jack 21 is positioned on the reaction wall 22 side, and the tip side of the rod is positioned on the opening side of the starting hole A. As shown in FIG. As a result, the main pushing jack 21 receives a reaction force from the reaction wall 22 at the base end of the cylinder via the push angle 23 and the strut 24, and can be extended and contracted by advancing and retracting the rod.

The push angle 23 and the strut 24 are thrust receiving members positioned between the main pushing jack 21 and the reaction wall 22 and functioning to start the excavator main body 10 by extension of the rod of the main pushing jack 21. Yes, and the configuration and shape described above may be different.

The original push jack 21 propels the segments 31 and 32 forward via the push ring 25 by extension of the rod. The push ring 25 is, for example, made of steel and has a short cylindrical shape, and is supported by the cradle C. As shown in FIG.

Each of the segments 31 and 32 is a short cylindrical (ring-shaped) member as a whole formed by assembling a plurality of steel members, such as six, for example, and serves as the erector at the rear of the excavator body 10. Assembled by workers using

Temporary segment 31 is a temporary segment located in launch shaft A and is removed after permanent segment 32 has been constructed, here with only one ring. On the other hand, the permanent segment 32 is part of the wall of the tunnel, and is continuously assembled in front of the temporary assembly segment 31 in a large number of rings. When the excavator main body 10 starts moving, only one ring of the temporary assembly segment 31 is installed between the propulsion jack 13 at the tip of the main pushing jack 21 and the rear end of the excavator main body 10 in the longitudinal direction. .

Furthermore, referring to FIG. 3, when the pistons of all the original pushing jacks 21 are completely retracted, the excavator main body is filled in the space between the strut 24 and the side surface of the mouth of the starting hole A in the longitudinal direction. The total length of the push angle 23 and the strut 24 in the front-rear direction is determined so that the strut 10 can be arranged. The push angle 23 and the strut 24 also have the function of adjusting the distance between the original pushing jack 21 and the reaction force wall 22 .

Hereinafter, the initial excavation method of the shield excavator 100 according to the embodiment of the present invention will be described with reference to FIG. 4 as well.

First, the step of arranging the main pushing device 20 composed of the pushing jack 21, the anti-pressure wall 22, the push angle 23 and the strut 24 in the starting hole A (S1) is performed.

Next, an excavator main body arranging step ( S2) is performed.

Next, a ground excavation step (S3) is performed in which the excavator main body 10 is pushed forward by extending the piston of the main push jack 21 to excavate the ground ahead of the opening of the starting hole A.

Next, in the rear part of the excavator body 10, a segment in which only one ring of the temporary assembly segment 31 is installed between the front end portion of the main pushing jack 21 and the propulsion jack 13 at the rear end portion of the excavator body 10 in the front-rear direction. A temporary assembly step (S4) is performed.

Next, the excavator main body 10 is propelled forward, and a permanent segment 32 is installed in the rear part of the excavator main body 10 in front of the wall surface of the opening of the starting hole A, connected to the temporary assembly segment 31. Then, the main segment assembly step (S5) is performed. By continuously performing the segment main assembling step (S5), it is possible to construct a tunnel in which the permanent segments 32 are continuous in the front-rear direction.

In the segment main assembly step (S5), the excavator main body 10 is propelled forward by extending the propulsion jack 13 . Here, if the permanent segment 32 does not exist, or if the number of rings of the permanent segment 32 does not reach a predetermined number, the reaction force of the propulsion jack 13 is applied to the reaction wall via the temporary assembly segment 31 or the like. 22, if there are more permanent segments 32 than a predetermined number of rings, the permanent segments 32 may be taken.

After a predetermined number of rings or more of the permanent segments 32 are installed and the reaction force of the propulsion jacks 13 can be taken from the permanent segments 32, the main pushing device 20 and the temporary assembly segment 31 are dismantled and removed from the starting shaft A. A dismantling step (S6) is carried out to carry out to the outside.

As described above, according to the present embodiment, only one ring of temporary assembly segment 31 is installed between the front end portion of the main pushing jack 21 and the propulsion jack 13 at the rear end portion of the excavator main body 10 in the longitudinal direction. not. As a result, the number of rings of the temporary assembly segment 31 to be dismantled after the permanent segment 32 is installed can be reduced compared to the conventional case, so that the work can be shortened.

Further, since the main pushing jacks 21 are horizontally spaced apart and work can be performed in the space between them, work in the vicinity of the rear portion of the permanent segment 32 can be simplified.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified as appropriate. For example, although the case where only one ring of the temporary assembly segment 31 exists between the front end of the pushing jack 21 and the rear end of the excavator main body 10 in the front-rear direction, two rings may exist.

DESCRIPTION OF SYMBOLS 10... Excavator main body 11... Shield tube 12... Cutter head 13... Propulsion jack 20... Base push device (shield excavator base push device) 21, 21a, 21b... Base push jack, 22... Counter pressure wall 23... Push angle 24... Strut 25... Push wheel 31... Temporary assembly segment 32... Permanent segment 100... Shield excavator A... Starting well B... Ground C... Wellhead concrete D... Cradle E... Support base.

Claims (4)

A main pushing device used during initial excavation of an excavator body having a propulsion jack at the rear end,
at least two push jacks horizontally spaced apart to push the excavator body forward;
When the excavator main body is arranged in the starting hole, the excavator main body is positioned between the front end portion of the contracted main pushing jack and the wall surface on the mouth side of the starting hole in the front-rear direction, and
A maximum temporary assembly segment to be dismantled after the segment constituting a part of the tunnel is fully assembled between the front end of the main pushing jack and the propulsion jack at the rear end of the excavator body in the front-rear direction. A shield excavator main pushing device characterized by being installed with two rings. The shield excavator main pushing device according to claim 1, wherein the main pushing jack is a multistage jack. 3. The method according to claim 1, wherein at least one of a pushing angle and a strut is present between the base end of the pushing jack and the wall surface on the opposite side of the starting hole in the front-rear direction. shield excavator main pusher. locating at least two horizontally spaced drive jacks in the launch shaft;
disposing an excavator main body having a propulsion jack at its rear end in the starting hole between the front end portion of the main pushing jack in a contracted state and the wall surface on the mouth side of the starting hole in the front-rear direction;
a step of pushing the excavator body forward by extending the piston of the original pushing jack to excavate the ground ahead of the opening of the starting hole;
A step of installing temporary assembled segments of maximum two rings in the rear part of the excavator main body between the front end of the main pushing jack and the propulsion jack at the rear end of the excavator main body in the longitudinal direction. and,
The excavator main body is propelled forward using the propulsion jack, and the rear part of the excavator main body, which is in front of the wall surface of the opening of the starting hole, is connected to the temporary assembly segment. a step of assembling the design segment ;
The initial excavation method for a shield excavator, wherein the temporary assembly segment is a segment to be dismantled after the segment constituting a part of the tunnel is actually assembled.

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