JP4698458B2 - Construction method for underground structures - Google Patents

Description

  The present invention mainly embeds and constructs an underground structure that becomes an underground passage in the ground directly below these tracks and roads across the track and under the road. It is related with the construction method of an underground structure which pushes and embeds an underground structure while performing the edge cutting of this and preventing the movement of the upper ground.

  Conventionally, as described in Patent Document 1, as a method for constructing an underground passage by burying an existing underground structure in a ground under a track or a road, at least in an underground structure to be embedded in the ground A holding frame is projected integrally from the front end surface of the upper floor portion, and a plurality of small cylindrical blade edges are slidably fitted back and forth in the holding frame, and the rear end face of the small cylindrical blade edge A propulsion jack is interposed between the front end surface of the upper floor portion of the underground structure, and the tip of the elongated friction cut plate disposed on the upper surface of the underground structure is fixed to the upper surface of the front end portion of each small cylindrical blade edge, By setting the underground structure on the start shaft side with one side across the track or road as the start shaft side and the other side as the reach shaft side, the propulsion jack is extended to sequentially specify the small cylindrical blade edges. Propelled into the ground for a long time, propulsion of this small cylindrical blade Subsequent to the small blade edge group, the underground structure is propelled by the same length, and this is repeated to embed and construct the underground structure between the starting shaft and the reaching shaft. .

According to the construction method of such an underground structure, when the small cylindrical blade edge is propelled for a certain length by the propulsion jack prior to the underground structure, the friction disposed on the upper surface of the underground structure Since the cut plate is also propelled integrally with the small blade edge, when the underground structure is propelled, the underground structure will be propelled along the lower surface of the friction cut plate, so that the upper ground moves. It has the advantage that it can be buried without making it.
Japanese Patent Publication No.59-27833

  However, according to the construction method of the underground structure, when the small cylinder blade edge is propelled forward from the holding frame by the propulsion jack, the small cylinder blade edge is caused to open by the load of the upper ground. As a result, the ground may bend downward and the ground may be loosened or collapsed. In addition, all the small cylindrical blade edges that are juxtaposed in the horizontal direction must be propelled in the correct direction. Therefore, there is a step between the friction cut plates arranged on each blade edge, and the underground structure can be smoothly pushed and buried along the lower surface of the friction cut plate row. There was a fear of disappearing.

  Furthermore, when propelling the underground structure, the friction cut plate tries to move forward integrally with the underground structure due to the frictional force between the upper surface of the underground structure and the lower surface of the friction cut plate. A phenomenon that tries to lift the upper ground with the upper surface of the front end as a fulcrum occurs at the small cylindrical blade edge to which the front end is fixed, and the friction cut plate may be deformed, and the propulsion resistance increases. There was a problem that smooth promotion was not possible.

  The present invention has been made in view of such problems, and the object of the present invention is to accurately propel a pipe on which a friction cut plate is placed in a predetermined direction without bending downward. Following the propulsion of the pipe, when the underground structure is propelled and embedded along the lower surface of the friction cut plate extending backward from the pipe, the friction cut plate is prevented from co-movement. It is to provide a construction method of an underground structure that can be propelled.

In order to achieve the above object, the construction method of the underground structure of the present invention is as described in claim 1, when constructing an underground passage by propelling and burying the underground structure from the start shaft to the arrival shaft. In addition, a plurality of pipes are supported side by side on the upper surface of the cutting edge attached to the front end opening of the underground structure so as to be slidable back and forth to form a pipe roof with these pipe rows and each pipe. A friction cut plate is placed on the upper surface of the pipe and the front end of the friction cut plate is integrally fixed to the front end of the pipe, while the rear portion is placed on the upper surface of the upper floor of the underground structure. The underground structure is buried in the ground by repeating the process of digging into the ground for a certain length and the process of propelling and burying the underground structure in the ground for a certain length following the excavation of this pipe roof, Construction That in the method, wellhead side of the starting pit the hydraulic jack by arranging the hydraulic jack on the rear of the friction cut plate from the wellhead of the starting pit and protrudes rearward is placed on the top floor upper surface of the underground structures Between the reaction force supporting steel material fixed to the earth retaining wall of the ground and the reaction force receiving bracket fixed to the rear end of the friction cut plate, and by extending this hydraulic jack, the ground on the wellhead side is used as a supporting point It is configured to apply a tensile force to the friction cut plate via the reaction force receiving bracket, and when the pipe roof is drilled, the friction cut plate on the pipe is pulled backward with a constant tensile force. Therefore, when the underground structure is propelled, all friction cut plates on the pipe roof are pulled. Accordingly, it characterized in that to prevent the co-movement of the underground structure of the friction-cut plate during propulsion.

  In the construction method of the underground structure configured as described above, the invention according to claim 2 is configured to propel the underground structure from the start shaft side to the arrival shaft side, and to dig ahead of the underground structure during the embedding. Each time the pipe roof is dug for a predetermined length, the front end surface of the fixed length friction cut plate is brought into contact with the rear end surface of the friction cut plate placed on the upper floor of the underground structure from each pipe by welding. It is characterized by adding.

  According to the first aspect of the present invention, when the underground structure is propelled and buried in the ground, after the friction cut plate on each pipe of the pipe roof to be propelled before the underground structure is propelled and buried. Since a constant tensile force is applied to the end in the direction opposite to the propulsion direction, the pipe that integrally fixes the front end of the friction cut plate to the upper surface of the front end is raised upward by the tensile force. The pipe is biased in a direction to cause warping, and the biasing force can surely prevent the pipe from being bent downward due to the load of the upper ground. The friction cut plate can be laid in the ground with high accuracy.

  Furthermore, after propelling all the pipes for a certain length, when propelling the underground structure, the rear ends of all the friction cut plates on the pipe roof made of the pipe row are pulled backward, The frictional force between the upper surface of the upper floor portion of the underground structure and the lower surface of the friction cut plate can reliably prevent the friction cut plate from co-operating with the underground structure. Movement or relaxation of the upper ground due to movement of the plate can be prevented.

Further, the tension means for the friction cut plate during the excavation of each pipe of the pipe roof and the tension means for the friction cut plate during the propulsion of the underground structure are common tension means, and are provided rearward from the wellhead of the starting shaft. Between the reaction force support steel material that is fixed on the rear end of the friction cut plate and the reaction force support steel material that has been installed on the protruding friction cut plate and fixed to the earth retaining wall of the ground on the wellhead side. By extending this hydraulic jack, it is configured to apply a tensile force to the friction cut plate via the reaction force receiving bracket with the ground on the wellhead side as a support point. By operating the hydraulic jack, the pipe can be kept horizontal against the upper ground load through the friction cut plate. The pipe on which the friction cut plate is placed is applied by applying a load and applying a certain tensile force and contracting the rod of the hydraulic jack in synchronization with the propulsion of the pipe while maintaining this load state. It can be propelled accurately.

  Furthermore, when propelling an underground structure, the friction cut plate is kept in an immobile state by maintaining the state in which the friction cut plate is loaded in the tension direction with the above-mentioned constant pressure without expanding or contracting the hydraulic jack. Therefore, the underground structure can be propelled and buried accurately and smoothly along the lower surface of the friction cut plate without any adverse effect on the upper ground.

  According to the invention of claim 2, when the underground structure is propelled and buried from the start shaft side toward the arrival shaft side, the pipe roof that excavates in advance of the underground structure has a predetermined length. Each time, the front end surface of the fixed length friction cut plate is brought into contact with the rear end surface of the friction cut plate placed on the upper floor of the underground structure from each pipe, and is added by welding. The upper surface of the upper floor portion of the structure can be smoothly propelled and buried up to the reach shaft while being always in sliding contact with the lower surface of the friction cut plate.

  A specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a track in which an underground structure 1 is propelled and buried in a reaching shaft (not shown) from the start shaft B in the ground below the track A. When constructing an underpass that crosses the bottom, the friction cut plate 2 is propelled into the ground prior to the underground structure 1, and the underground structure 1 is propelled along the lower surface of the friction cut plate 2. The underground structure 1 is made of a ready-made reinforced concrete box having a rectangular cross section penetrating in the front-rear direction, and a blade edge 3 is attached to the front end opening thereof.

  The blade edge 3 has a rear end frame portion 3a having substantially the same cross-sectional shape as the rectangular cross section of the underground structure 1 joined to the front end surface of the underground structure 1 and is fixed integrally therewith, and the rear end frame portion 3a. From the upper surface of the upper floor portion 1a of the basement structure 1 to the front, with the same dimension as the thickness of the upper floor portion 1a or the dimension below the thickness of the upper floor portion 1a. A base frame 3b having a fixed length is projected horizontally, and further, a lower frame is formed at the front lower end portion of the rear end frame portion 3a that is shorter than the length of the base plate 3b and whose tip is formed at the blade edge portion. The front ends of both side frame portions 3d and 3d are inclined obliquely rearward from the upper end connecting the base plate 3b and the front ends of the lower frame portion 3c to the lower end. It is formed in the blade edge part over the entire length.

  On the front half of the base plate 3b of the blade edge 3 configured in this way, a plurality of pipes 4 of a fixed length made of steel pipes having a rectangular cross section are juxtaposed in the horizontal direction as shown in FIG. In this state, the rear surface of the rear portion is placed and supported to form a pipe roof P, and each pipe 4 is configured to be independently movable in the front-rear direction. These pipes 4 have a height (thickness) set so that the upper surface thereof is flush with the upper surface of the upper floor portion 1a of the underground structure 1.

  A screw auger 5 is rotatably disposed in each pipe 4 with its front end cutter head 5 a facing forward from the front end opening of the pipe 4, and at the rear end face of the pipe 4. The rotary drive motor 6 is pressed through a pressing member (not shown), and the rotary shaft of the rotary drive motor 6 is detachably connected to the rear end of the screw auger 5 through a joint (not shown). The rotary auger 5 is rotated by the rotary drive motor 6, and the rotary drive motor 6 is connected between the rear end surface of the pipe roof P and the upper end of the rear frame 3a of the blade edge 3. The pipe propulsion jack 7 is integrally connected to the front end of the pipe propulsion jack 7 disposed on the rear half of the base plate 3b and receiving the propulsion reaction force on the rear frame portion 3a. Rotation drive mode by It is configured to propel the pipe 4 forward from motor 6 via the pressing member.

  The propulsion jack 7 provided with the rotational drive motor 6 is disposed behind each pipe 4 constituting the pipe roof P, but moves laterally on the rear half of the base plate 3b of the blade edge 3. A carriage may be provided, and a pipe propulsion jack 7 having a rotational drive motor 6 may be attached to the laterally movable carriage. When configured in this way, a rotational drive motor is provided behind each pipe 4. It is not necessary to dispose the pipe propulsion jack 7 provided with 6, and the laterally moving carriage is moved to the rear of the pipe 4 to be propelled, and the pipe propelling jack 7 on the laterally movable carriage is moved behind the blade edge 3. The rotational drive motor 6 is pressed against the rear end surface of the pipe 4 through a pressing member by applying a reaction force to the front surface of the side frame 3a and slightly extending, and the rotation shaft is connected to the rear end of the screw auger 5. In this state, the rotational drive motor 6 The pipe 4 can be dug forward by extending the pipe propulsion jack 7 while operating.

  Further, the friction cut plate 2 made of a strip steel plate is placed on the flat upper surface of each pipe 4, and the front end of the friction cut plate 2 is integrally fixed to the upper surface of the front end of the pipe 4 by welding. The width of the friction cut plate 2 is formed to be substantially equal to the width of the pipe 4 and the rear portion of the friction cut plate 2 is placed on the upper surface of the upper floor portion 1a of the underground structure 1 from the wellhead of the start shaft B. The rear end of the friction cut plate 2 is protruded rearward, and a tensile force is applied rearward to the rear end portion of the friction cut plate 2 by the tension means 8, and the tension is applied to the fixing portion by welding between the front end of the friction cut plate 2 and the front end of the pipe 4. Force is transmitted, and the pipe 4 is configured to be biased in a direction to bend upward against a load received from the ground.

  As shown in FIGS. 1 and 2, the tension means 8 has a hydraulic jack 8 a directed in the longitudinal direction, which is the length direction of the friction cut plate 2, on the rear portion of the friction cut plate 2 protruding into the start shaft B. The hydraulic jack 8a is horizontally disposed, and the earth retaining wall 10 covering the ground at the top end of the ground on the wellhead side of the start shaft B and the reaction force supporting steel material 8b fixed to the earth retaining wall 10 are provided. A plurality of members having a constant thickness on the front surface of the reaction force receiving bracket 8c that is removably fixed to the upper surface of the rear end portion of the friction cut plate 2 while supporting the rods of the hydraulic jack 8a facing backward. It is received via the spacer piece 17 and the rod of the hydraulic jack 8a is actuated in the extending direction to generate a tensile force between the reaction force supporting steel material 8b and the reaction force receiving bracket 8c, and friction is generated by this tensile force. The cut plate 2 is configured to give a tensile force.

  On the other hand, the underground structure 1 is installed on the bottom plate 11 having a flat top surface laid on the bottom surface of the start shaft B so as to be slidable in the front-rear direction. A plurality of underground structure propulsion jacks 9 are disposed between the disposed reaction force receivers 13 via a plurality of spacers 14, and the front end surfaces of these propulsion jacks 9 are joined to the rear end surface of the underground structure 1. The tip of the rod of the propulsion jack 9 that is fixed in a state of being pressed against the rear surface of the press ring 15 and protrudes backward is brought into contact with the front surface of the foremost spacer 14 made of a plate material or a frame material having a certain thickness. The underground structure 1 is configured to be propelled and buried in the ground from the shaft of the start shaft B by extending the rod of the propulsion jack 9 after being received.

  The underground structure 1 is propelled and buried by sequentially propelling all the pipes 4 constituting the pipe roof P into the ground by a certain length and after the certain length of propulsion process of the pipe roof P. This is performed by sequentially repeating the step of propelling the object 1 by the same length. In addition, when the friction cut plate 2 drawn out from the top of each pipe 4 to the upper floor portion 1a of the underground structure 1 behind it is propelled together with the pipe 4 and embedded in the ground for a certain length, it starts. The front end surface of the friction cut plate 2 having a predetermined length is abutted with the rear end surface of the friction cut plate 2 exposed in the shaft B, and is added by welding.

  In order to propel all the pipes 4 constituting the pipe roof P by a certain length, first, the rear portion protruding into the start shaft B in the friction cut plate 2 placed on one pipe 4 to be propelled. A hydraulic jack 8a as a tension means 8 is disposed on the top as shown in FIG. 2, and its longitudinal direction is preliminarily applied to the upper end of the earth retaining wall 10 with its front end surface orthogonal to the friction cut plate row. The reaction force support steel material 8b fixed in a direction crossing the cut plate row is abutted against the rear surface of the steel plate 8b and fixed in the received state, and the rod end of the hydraulic jack 8a is fixed to the friction cut plate 2 The reaction force receiving bracket 8c fixed to the upper surface of the rear end is in a state of being received through a plurality of spacer pieces 17 having a certain thickness, and in this state, the rod is fixed in the direction in which the rod extends to the hydraulic jack 8a. load Multiplied by interposing such that 突張 state the hydraulic jacks 8a between the reaction force supporting steel 8b and reaction force receiving bracket 8c.

  In this state, the propulsion jack 7 provided with the rotary drive motor 6 disposed on the base plate 3b of the blade edge 3 behind the pipe 4 is extended to propel the pipe 4 as shown in FIG. The ground in front is excavated while rotating the screw auger 5 in the pipe 4 by the rotation drive motor 6. At this time, the rod of the hydraulic jack 8a is contracted by a length corresponding to the propulsion amount of the pipe 4 while maintaining a state in which a constant load is applied to the friction cut plate 2 by applying a certain load to the hydraulic jack 8a. By doing so, the pipe 4 is dug integrally with the friction cut plate 2. Specifically, as the pipe 4 is propelled, an acting force is applied to contract the rod of the hydraulic jack 8a, and the tensile force applied to the pipe 4 via the friction cut plate 2 is also increased as the cylinder pressure is increased. At this time, by releasing a certain amount of pressure oil in the cylinder according to the propulsion amount of the pipe 4, the cylinder pressure is kept constant while the rod is contracted, and the tensile force applied to the pipe 4 is made constant. Can keep.

  When a certain tensile force is applied to the friction cut plate 2 by the hydraulic jack 8a, the tensile force is transmitted to the fixing portion by welding between the front end of the friction cut plate 2 and the front end of the pipe 4, and the pipe 4 is connected to the blade edge 3 As a result, an acting force is generated to bend upward against the load received from the upper ground with the base plate 3b as a fulcrum. By this acting force, the pipe 4 can be propelled while maintaining the horizontal state as the planned propulsion direction without moving downward due to the load from the upper ground or its own weight.

  At this time, the tensile force applied to the pipe 4 by the hydraulic jack 8a via the friction cut plate 2 is naturally set to be smaller than the propulsive force by the pipe propulsion jack 7, but even in this state, the blade 3 If the front end of the pipe 4 is moved downward due to the load or weight of the upper ground applied to the front end of the pipe 4 in a cantilever-supported state protruding forward from the base plate 3b, the friction cut plate 2 As a result, the hydraulic jack 8a generates a working force to further contract the rod, the cylinder pressure of the hydraulic jack 8a rises, and the tensile force to maintain the horizontal state increases, so compared with the hydraulic jack 8a. The pipe 4 can be propelled in the correct direction only by applying a small constant load.

  In addition, when it is necessary to detect whether the pipe 4 is excavated on the planned buried line, that is, to detect the level, for example, a space at one corner in the pipe 4 is used as such a detecting means. A measuring instrument (not shown) having a reflecting mirror and a target is attached to the corner of the pipe 4 by using a laser beam oscillator and a distance measuring instrument on the base plate 3b of the blade 3 at the rear of the measuring instrument. (Not shown) can be used to detect the laser beam by irradiating the target of the measuring instrument with a laser beam from the oscillator.

  Thus, after digging one pipe 4 into the ground for a certain length, the pipe 4 adjacent to the pipe 4 is screw auger while preventing the pipe 4 from moving downward by the hydraulic jack 8a in the same manner as described above. 5 is driven in a horizontal direction by a rotation drive of 5 and the extension of the propulsion jack 7. At this time, the hydraulic jack 8a used at the time of excavation may be rearranged on the rear end portion of the friction cut plate 2 on the pipe 4 to be propelled next. However, as shown in FIG. Two (or two or more) hydraulic jacks 8a, 8a are prepared, and these hydraulic jacks 8a, 8a are respectively arranged for the pipe 4 to be propelled first and the pipe 4 to be propelled next. In addition, one hydraulic jack 8a previously used for propelling the pipe 4 is replaced with the pipe 4 to be propelled next to this pipe 4 during the propulsion of the next pipe 4 by the other hydraulic jack 8a. It is desirable to keep it.

  When propelling the pipe 4, the hype 4 is in sliding contact with the opposite side surfaces of the pipes 4, 4 adjacent to both sides, and both end faces of the friction cut plate 2 on the pipe 4 are on the pipes 4, 4 on both sides. The friction cut plate 2 moves forward while sliding on the opposite end face. The earth and sand excavated by the cutter head 5a of the screw auger 5 disposed in each pipe 4 is carried out backward by the screw auger 5 and opened to the lower surface of the rear end of the pipe 4 (not shown). ) And the earth and sand excavated by the blade 3 and the soil ground excavated by appropriate excavating means from the blade 3 through the underground structure 1. It is discharged and removed to the start shaft B side.

  Then, as shown in FIG. 5, when the pipes 4 are sequentially excavated and all the pipes 4 constituting the pipe roof P are excavated for a certain length, as shown in FIG. Since the vertical front surface of the reaction force receiving bracket 8c fixed to the upper surface of the rear end portion of the cut plate 2 is continuously flush with the width direction of the underground structure 1, the width of the pipe roof P is substantially reduced. All the reaction forces that are arranged so that a single reaction force beam 16 having the same length crosses over the rear part of the friction cut plate row and the rear surface of the reaction force beam 16 is flush with the surface. It is received on the front surface of the receiving bracket 8c via a certain length of interposition member or the plurality of spacer pieces 17.

  After that, several (four in the figure) hydraulic jacks 18 are interposed between the reaction force supporting steel material 8b and the reaction force receiving beam 16 at a desired interval in the width direction of the friction cut plate row and the front end thereof. The surface of the rod is supported by the reaction force support steel 8b and the tip of the rod facing backward is pressed against the reaction force receiving girder 16, and a load is applied to these hydraulic jacks 18 from the reaction force receiving beam 16 to the spacer piece 17 and the reaction force. All friction cut plates 2 are held in a state where a tensile force is applied to the rear via the receiving bracket 8c.

  In this state, a plurality of propulsion jacks 9 arranged in the start shaft B are extended as shown in FIG. 7, and a reaction force is applied to the reaction force receiver 13 through the spacers 14 so that the underground structure 1 Is propelled forward by the same propulsion length as the pipe roof P while the upper surface of the upper floor portion 1a is in sliding contact with the lower surface of the friction cut plate row. At this time, the front ground is excavated by the cutting edge 3 attached to the front end opening of the underground structure 1 and the front ground surrounded by the cutting edge 3 is excavated by an appropriate excavation means. In synchronization with the propulsion of 1, the above-mentioned several hydraulic jacks 18 are held in a state where the tensile force is applied to all the friction cut plates 2 to make the friction cut plates 2 immobile, These friction cut plates 2 are prevented from moving forward due to the sliding force with the upper floor portion 1a of the underground structure 1.

  In addition, when a pipe propulsion jack 7 is interposed between the rear end of each pipe 4 and the rear frame portion 3a of the blade edge 3 in contact with the front end surface of the upper floor portion 1a of the underground structure 1 The pipe propulsion jack 7 is also contracted in synchronism with the propulsion of the underground structure 1. As the several hydraulic jacks 18, the hydraulic jack 8a used as the pulling means when the pipe 4 is dug is reused, and when the number of the hydraulic jacks 8a is insufficient, the hydraulic jacks having the same structure are used. Alternatively, a hydraulic jack different from the hydraulic jack 8a used when all the hydraulic jacks 18 are excavated in the pipe 4 may be used.

  In this way, by applying a constant tensile force to the friction cut plate 2 backward by the hydraulic jack 8a, the pipe propulsion jack 7 prevents each pipe 4 from moving downward while preventing the front end portion of the pipe 4 from moving downward. Are sequentially excavated in the horizontal direction, and a pipe roof P made of these pipe rows is propelled into the ground forward by a fixed length toward the reaching shaft side. The underground structure is extended by the same distance as the pipe roof P by extending the propulsion jack 9 disposed on the start shaft B side while applying a tensile force to the plate 2 to prevent the friction cut plate 2 from moving forward. The step of propelling the object 1 forward is repeated.

  At this time, every time the pipe roof P is propelled for a certain length, the friction cut plate 2 in which only the front end of each pipe 4 is fixed to the upper surface of the front end of the pipe 4 by welding is also integrally propelled to the inside of the start shaft B The length of the projecting portion of the spacer is shortened, and the spacer interposed between the hydraulic jack 8a as the tension means 8 and the reaction force receiving bracket 8c fixed to the upper surface of the rear end of the friction cut plate 2 accordingly. The number of pieces 17 used will also decrease.

  Then, after all the spacer pieces 17 have been removed, the pipe 4 is brought into a state in which the rod of the hydraulic jack 8a is in direct contact with and received by the reaction force receiving bracket 8c as shown in FIGS. Next, as shown in FIG. 10, the hydraulic jack 18 (8a) is used for friction with the reaction force receiving girder 16 in direct contact with the front surface of all reaction force receiving brackets 8c. After the underground structure 1 is propelled while applying a certain tensile force to the cut plate 2, the rear end of all the friction cut plates 2 when the underground structure 1 has not yet reached the shaft. After cutting off the reaction force receiving bracket 8c fixed to the upper surface, welding is performed with the front end surface of a new friction cut plate having a certain length joined to the rear end surface of the friction cut plate 2 by welding. Connected to the same manner as described above, again, and the promotion of the pipe roof P, repeatedly performing promote underground structures 1 subsequent to this promotion.

  Similarly, every time the underground structure 1 is excavated into the ground for a predetermined length, a spacer 14 having a thickness corresponding to the excavation length is interposed in the start shaft B at the rear side of the propulsion jack 9, and the underground structure When the length of the underground passage to be constructed by the object 1 is long, the underground structure 1 of a certain length obtained by dividing the length of the underground passage into several parts is sequentially pushed while being joined and connected to reach the reaching shaft, An underpass by this underground structure 1 is constructed between the starting shaft B and the reaching shaft.

A simplified longitudinal side view of a state in which a friction cut plate is propelled into the ground for a certain length in advance of an underground structure. The simplified plan view. The simplified front view of a pipe roof and an underground structure. The simplified vertical side view of the state which is pushing the pipe. A simplified plan view of a state in which a plurality of friction cut plates are propelled for a certain length. The simplified top view of the state which arranged the reaction force receiving girder. A simplified longitudinal side view of a state where an underground structure is propelled for a certain length in the ground following the friction cut plate. The simplified vertical side view which shows the state which is pushing the rear-end part of a friction cut board in the ground. The simplified plan view. The simplified longitudinal side view of the state where the underground structure is propelled for a certain length in the ground after propulsion of the friction cut plate.

A Track B Starting shaft P Pipe roof 1 Underground structure 2 Friction cut plate 3 Cutting edge 4 Pipe 5 Screw auger 6 Rotation drive motor 7 Pipe propulsion jack 8 Tensioning means
8a hydraulic jack
8c Reaction force receiving bracket 9 Propulsion jack
16 Reaction force girder
17 Spacer piece

Claims (2)

When constructing an underground passage by propelling and burying an underground structure from the starting shaft to the arrival shaft , multiple pipes are installed side by side on the upper surface of the blade attached to the front end opening of the underground structure. In addition, a pipe roof is formed by these pipe rows supported slidably back and forth, and a friction cut plate is placed on the upper surface of each pipe, and the front end of the friction cut plate is integrally fixed to the front end of the pipe. On the other hand, the rear portion is placed on the upper surface of the upper floor portion of the underground structure, and in this state, the pipe roof is excavated into the ground for a fixed length, and the underground structure is fixed to a predetermined length following the excavation of the pipe roof. , propulsion in the ground, buried underground construction in the ground by repeatedly performing a step of embedding, in a method of construction, the wellhead of the starting pit and protrudes rearward mounting the top floor upper surface of the underground structures A hydraulic jack is disposed on the rear portion of the friction cut plate, and the hydraulic jack is fixed to the retaining wall of the ground on the wellhead side of the starting shaft and fixed to the rear end of the friction cut plate. By interposing between the reaction force receiving brackets and extending this hydraulic jack, the pipe is configured to apply a tensile force to the friction cut plate via the reaction force receiving bracket with the ground on the wellhead side as a supporting point. When excavating each pipe of the roof, the friction cut plate on the pipe is pulled backward with a constant tensile force to prevent downward movement of the front end of the pipe during excavation. Keeping all the friction cut plates on the roof stretched rearward, the friction cut plates are used together with the underground structure during propulsion. Construction method of underground structures, characterized in that to prevent the can.   The underground structure is propelled and buried from the starting shaft side to the reaching shaft side, and each time the pipe roof that digs ahead of the underground structure has a predetermined length, the upper floor of the underground structure is The construction method of an underground structure according to claim 1, wherein the front end surface of the friction cut plate having a predetermined length is brought into contact with the rear end surface of the friction cut plate placed thereon and welded.

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