JP4948142B2 - How to build an underpass - Google Patents

Description

  The present invention relates to a method for constructing an underground passage and a tension adjusting device, and more particularly, to an underground passage that forms an underground passage by replacing a pipe roof formed in the ground with an underground passage outline structure with a friction cut member remaining in the ground. The present invention relates to a construction method and a tension adjusting device used in the construction method of the underpass.

  For example, as a method of constructing an underground passage in a state where it crosses the existing railroad tracks and the lower ground of the road, for example, the existing railroad tracks and roads from the lower ground to the upper ground of the planned underground passage section where the underground passage is planned to be constructed A pipe roof for supporting and protecting is formed, for example, by installing a plurality of circular steel pipes arranged side by side in the horizontal direction, and excavating the lower ground while supporting the pipe roof to construct an underground passage After securing a working space, a method of constructing an underground passage by installing a formwork or placing concrete has been generally adopted, but this method is located below the pipe roof from the section of the underground passage. Since it is necessary to form a work space with a considerably large cross section, it is not an efficient construction method, and it tends to affect the existing railroad tracks and roads above.

  For this reason, as an alternative to the conventional method of constructing an underground passage by providing a work space below the pipe roof, the pipe roof formed in the ground, for example, made of precast, with the friction cut member remaining in the ground An underpass construction method has been developed in which an underpass is formed by replacing the underpass with an underpass structure (see, for example, Patent Document 1).

  In the underpass construction method described in Patent Document 1, for example, as shown in FIGS. 5A to 5J, the friction cut member 51 is fixed to a surface arranged along the upper surface of the planned underpass 50 having a rectangular cross section. The plurality of box-shaped pipe members 52 including the box-shaped pipe member are pressed in parallel to at least the upper floor position 50a of the planned underground passage 50, for example, from the starting shaft 53 to the reaching shaft 54 (FIG. 5 (a ) And (b)), a pipe roof 55 penetrating the planned underpass 50 is formed in the ground (see FIGS. 5C and 5D). Thereafter, the end surface of the underground passage outline structure 56 having a rectangular cross section made of, for example, precast concrete is brought into contact with the end face of the pipe roof 55, for example, with the intermediate push jack 57 interposed therebetween, and the rear end of the underground passage outline structure 56 is further provided. A push jack 58 for propelling the subway outer shell structure 56 is installed in the section (see FIGS. 5E and 5F). Then, the friction cut is made by releasing the fixation with the box-shaped pipe member 52 while propelling the underground passage outer structure 56 while excavating and removing the sand and sand at the tip of the underground passage outer structure 56 using the blade member 59 or the like. With the member 51 left in the ground, the pipe roof 55 is pushed out and replaced with the underground passage outline structure 56 (see FIGS. 5 (g) and (h)), whereby the planned underground passage section 50 is replaced with the underground passage outline structure 56. An underpass 60 is formed.

Further, in the step of replacing the pipe roof 55 by propelling the underground passage outline structure 56 while excavating and removing the sand and sand at the tip of the underground passage outline structure 56 using the blade member 59 or the like (FIG. 5 (g ), (H)), the friction cut member 51 and the underground passage outline structure 56 may cause the friction cut member 51 to move together with the underground passage outline structure 56 in the propulsion direction. Is also connected to the reaction force wall 62 of the start shaft 53 via a tie rod member 61 (see FIG. 5G), and a technique for preventing the frictional movement of the friction cut member 51 by the tension of the tie rod member 61 is also disclosed. (For example, refer to Patent Document 2).
JP-A-1-29597 Japanese Patent Laid-Open No. 7-208067

  On the other hand, in the process of propelling while replacing the above-described underpass outer structure 56 with the pipe roof 55 (see FIGS. 5G and 5H), the underpass outer structure 56 is composed of the main push jack 58 and the start shaft. A spacer member such as a spacer 63 or a stradd 64 is sequentially stacked and propelled by the push jack 58 between the reaction force walls 62 of 53 and the stroke of the push jack 58 (for example, 1 m). Will be. Further, in such a process, when a spacer member such as the spacer 63 or the straddle 64 is inserted from above the start shaft 53 and additionally disposed, the tie rod member 61 stretched across the upper portion of the start shaft 53 is obstructed. Therefore, for example, the tie rod member 61 is temporarily removed at the connecting portion of the unit tie rod member having a length of about 6 m via a coupler or the like, and spacer members 63 and 64 are additionally arranged. Thereafter, the tie rod member 61 is removed. A method is adopted in which the propulsion work of the underpass outer structure 56 is resumed by re-stretching.

  However, in the above-described underpass construction method, it is not easy to stretch the tie rod member 61, and a considerable distance is provided between the friction cut member 51 and the reaction force wall 62 on which the tie rod member 61 is stretched. Therefore, the tie rod member 61 is easily bent due to the weight of the tie rod member 61. In order to eliminate such bending, for example, there are measures such as tensioning a bolt at a fixing portion of the tie rod member 61 to the reaction force wall 62, tightening a coupler connecting the tie rod member 61, and supporting the tie rod member 61 from below. However, it was difficult to apply a sufficient tension to the tie rod member 61.

  In addition, when the tie rod member 61 is bent or the tension applied to the tie rod member 61 is insufficient, the friction cut member 51 and The frictional force with the underpass outer structure 56 may cause the friction cut member 51 to move together in the propulsion direction, and the ground above the friction cut member 51 is likely to be affected.

  The present invention has been made paying attention to such a conventional problem. When the tie rod member is re-tensioned, a predetermined tension is easily and surely applied to the tie rod member, and the friction cut member and the underpass are provided. An underpass construction method capable of effectively preventing the friction cut member from co-moving in the propelling direction of the underpass outer structure due to frictional force with the outer structure, and a tension adjusting device used in the underpass construction method The purpose is to provide.

According to the present invention, a plurality of box-shaped pipe members including a box-shaped pipe member having a friction cut member fixed to a surface arranged along the upper surface of the planned underground passage having a rectangular cross section are provided at least at the upper floor position of the planned underground passage. After forming a pipe roof penetrating into the ground in parallel and penetrating through the planned underground passage, the end surface of the underground passage outline structure having a rectangular cross section is brought into contact with the end surface of the pipe roof, and the underground passage outline While the excavation of the sand on the face of the face of the structure is excavated, the underpass structure is pushed from the start shaft by a push jack and the friction cut member released from the box-shaped pipe member is released into the ground. While leaving behind, the pipe roof is pushed out to replace the underpass outer structure, thereby forming an underpass with the underpass outer structure in the planned underpass portion. In the method of constructing a lower road, the underpass outer structure is propelled while additionally arranging a spacer member in the propulsion direction in sequence between the main push jack and the reaction wall of the starting vertical shaft, and the friction The cut member is a tie rod whose one end is supported and fixed to the reaction wall of the start shaft and whose other end is connected and fixed to the friction cut member with a tension adjusting device including a hydraulic jack provided with a pressure gauge interposed therebetween. After the tie rod member is removed once and the spacer member is additionally installed, the tie rod member is prevented from being moved together with the propulsion of the underpass outer structure by the tension of the member. when resuming the propulsion work of the underpass shell structure re-stretched, the tie rod member by the tension adjusting device, the tie rod portion Not drawn in by the pulling action of the friction cutting member in the starting pit side, and the After loading a predetermined tension of the co-migration can be prevented to the range of the friction cutting member, the step of performing the promotion work of the underpass shell body The above object is achieved by providing a method for constructing an underpass characterized by including

  In the underpass construction method of the present invention, the predetermined tension applied to the tie rod member by the tension adjusting device is at least an upper load acting on the friction cut member including the weight of the friction cut member. It is preferable that the tension is a value obtained by dividing a value obtained by multiplying the friction coefficient between the subway outer structure and the friction cut member by the number of the tie rod members.

  Further, the present invention is a tension adjusting device provided in a connecting portion of the other end portion of the tie rod member to the friction cut member, which is used in the above-described method for constructing an underpass, and one end portion is connected to the friction cut member. A first connection jig that is fixed and has a first jack support section at the other end, and a second jack support section that is disposed between one end of the first connection jig and the first jack support section. And a rod member that penetrates the first jack support portion in a loosely fitted state through a tie rod fastening portion disposed on the opposite side of the second jack support pressure portion across the first jack support pressure portion. A connected second connecting jig, and a hydraulic jack provided between the first jack supporting pressure part of the first connecting jig and the second jack supporting pressure part of the second connecting jig joined at both ends. The hydraulic cylinder The above-mentioned object is achieved by providing a tension adjusting device that extends a stick and pulls the tie rod fastening portion toward the friction cut member and applies a predetermined tension to the tie rod member. It is a thing.

  In the tension adjusting device of the present invention, the rod member that connects the second jack supporting pressure portion and the tie rod fastening portion of the second connection jig is constituted by a bolt member having a male screw portion, and the bolt When a nut member is screwed to a portion of the member between the first jack supporting pressure portion and the second jack supporting pressure portion, and when the predetermined tension is applied to the tie rod member by extending the hydraulic jack Preferably, the nut member is fastened to the first jack support pressure portion to maintain a state in which a predetermined tension is applied to the tie rod member.

According to the underpass construction method or tension adjusting device of the present invention, when the tie rod member is re- tensioned, the friction cut member is not pulled into the start shaft side by the pulling action of the tie rod member, and the friction cut member It is possible to easily and surely apply a predetermined tension within a range in which the co-movement of the friction cut member can be prevented , and the friction cut member and the underground passage outer structure to frictionally move the friction cut member in the propulsion direction of the underground passage outer structure. It can be effectively prevented.

  In the method for constructing an underpass according to a preferred embodiment of the present invention, the pipe roof 55 formed in the ground is replaced with an underpass outer structure 56 made of, for example, precast concrete while the friction cut member 51 is left in the ground. In the method for constructing the underground passage 60 that forms the underground passage 60 (see FIGS. 5A to 5J), the underground passage is removed while excavating the earth and sand on the face of the tip of the underground passage outer structure 56 using the blade member 59 or the like. When the outer shell 56 is pushed and the pipe roof 55 is pushed out and replaced with the underground passage outer shell 56 with the friction cut member 51 released from fixing to the box-shaped pipe member 52 left in the ground (FIG. 5 ( g), (h)), and the friction cut member 51 is caused by the frictional force between the friction cut member 51 and the subway outer structure 56 to be submerged. The propulsion direction of Zotai 56 are those that are employed in order to be able to effectively prevent the co-migration.

  Here, FIG. 1 is a step of replacing the underground passage outline structure 56 by pushing the pipe roof 55 formed in the ground by propelling the underground passage outline structure 56 of FIG. A state in which most part of the underpass outer structure 56 is propelled in the ground of the planned underpass 50 except for the rear end portion 56a of the body 56 is shown. Further, in the present embodiment shown in FIG. 1, in the start shaft 53, the main push jack 58 is extended by one stroke (for example, 1 m) while obtaining a propulsion reaction force from the reaction force wall 62, and the underpass outer shell 3 structure 56 is advanced. At the same time, the main push jack 58 is contracted for each stroke, and spacer members such as spacers 63 and struts 64 are sequentially stacked in the propelling direction X between the rear reaction force wall 62 and the main push The underpass structure 56 is propelled while the jack 58 is moved in the propulsion direction X. Further, in the present embodiment shown in FIG. 1, the friction cut member which is left unfixed with the box-shaped pipe member 52 (see FIGS. 5 (g) and 5 (h)) constituting the pipe roof 55 being released. 51, the end of the start shaft 53 side is integrally joined to a steel end member 65 made of, for example, H-shaped steel by welding or the like, and one end of the end of the start shaft 53 is connected to the steel end member 65. When the other end portion of the tie rod member 61 supported and fixed to the reaction wall 62 is connected and fixed via the tension adjusting device 10, the friction cut member 51 is pulled by the tie rod member 61, and the underground passage outline structure 56. Co-movement in the propulsion direction X is prevented.

  That is, the construction method of the underground passage of the present embodiment includes a plurality of box-shaped pipe members 52 including a box-shaped pipe member in which the friction cut member 51 is fixed to a surface arranged along the upper surface of the planned underground passage portion 50 having a rectangular cross section. Are pressed in parallel into at least the upper floor position 50a of the planned underground passage 50 to form a pipe roof 55 penetrating the planned underground passage 50 in the ground, and then the end surface of the pipe roof 55 has a rectangular cross section. The end surface of the subway outer structure 56 is brought into contact with the bottom surface of the subway outer structure 56, and the underground surface outer structure 56 is pushed out from the start shaft 53 by the pushing jack 58 while excavating and removing the sand and sand at the tip face of the subsurface outer structure 56. The pipe roof 55 is pushed out and replaced with the subway outer shell structure 56 with the friction cut member 51 released from being fixed to the pipe member 52 left in the ground. Thus, in the construction method of the underground passage that forms the underground passage 60 by the underground passage outer structure 56 in the planned underground passage portion 50 (see FIGS. 5A to 5J), as shown in FIG. The spacer members 63 and 64 are sequentially stacked in the propelling direction X between the main push jack 58 and the reaction force wall 62 of the start shaft 53 and are propelled, and the friction cut member 51 is connected to the start shaft 53. One end is supported and fixed to the reaction force wall 62 and the other end is connected and fixed to the friction cut member 51 with the tension adjusting device 10 interposed therebetween. Accordingly, after the tie rod member 61 is removed and the spacer members 63 and 64 are additionally installed, the tie rod member 61 is prevented. When the tension adjustment device 10 applies a predetermined tension to the tie rod member 61 when the tensioning device 10 resumes the propulsion work of the underpass structure 56 after re-stretching, the process includes the step of propelling the underpass outline structure 56. It is out.

  According to the present embodiment, the main push jack 58 can use various known hydraulic jacks used for propulsion work, shield work, etc., and has a pressing ability of about 1500 KN per unit, for example, 1 m Has a stroke length of about. A plurality of the push jacks 58 are distributed in a well-balanced manner along the rear end surface of the rectangular shape of the underpass outer structure 56 and attached in a balanced manner. With the board 66 interposed, the underpass structure 56 is pressed in the propulsion direction X toward the reaching shaft 54 (see FIG. 5G). Further, the push jack 58 obtains a propulsion reaction force from the reaction force wall 62 via spacer members 63 and 64 that are sequentially stacked in the propulsion direction X between the reaction force wall 62 of the start shaft 53 and the underground passage. The outer structure 56 is pressed in the propulsion direction X.

  As the spacer members 63 and 64, for example, various kinds of well-known spacer members that are made of steel or precast concrete and that are interposed between the main push jack 58 and the reaction force wall 62 and transmit the propulsion reaction force can be used. In this embodiment, a spacer 63 having a length of 1 m and a strut 64 having a length of 3 m are used in combination. That is, for each stroke of the main pushing jack 58, a spacer 63 having a length of 1 m is inserted between the spacer members 63, 64 at the front end and the contracted main pushing jack 58 and additionally arranged, and three spacers are provided. Every 63, these are used replacing the struts 64. The spacer members 63 and 64 arranged so as to overlap in the propulsion direction X are formed on the reaction force wall 62 in a stable state via a cross-girder frame 67 made of, for example, H-shaped steel at the rear end portion, as in the known technique. By abutting, the driving reaction force from the reaction force wall 62 is efficiently transmitted to the main push jack 58.

  The reaction force wall 62 can be easily formed by placing concrete with a thickness of, for example, about 1 m on the surface of the start shaft 53 facing the planned underpass 50 in the same manner as the known technology. A cross beam 67 is attached to the reaction force wall 62 using, for example, a concrete anchor, and one end of the tie rod member 61 is supported and fixed by being embedded in, for example, concrete or via a fixing bolt.

  The tie rod member 61 is made of, for example, a steel bar, a PC steel wire, a PC steel stranded wire, and the like, and one end portion thereof is supported and fixed to the reaction force wall 62 as described above, and the other end portion is a tension adjusting device described later. By being connected and fixed to the steel end member 65 via 10, it is connected and fixed to the friction cut member 51 joined integrally to the steel end member 65. The tie rod member 61 is attached across the upper portion of the start shaft 53 corresponding to the height position of the friction cut member 51 left in the ground. Further, the tie rod member 61 can be used as one continuous member extending from the reaction force wall 62 to the steel end member 65. For example, a unit tie rod member having a length of about 6 m is connected via a coupler or the like. It can also be used in conjunction with the required length.

  In the present embodiment, the tension adjusting device 10 that is interposed between the steel end member 65 and connects and fixes the other end portion of the tie rod member 61 to the friction cut member 51 is, as shown in FIG. One end portion 11 a is connected and fixed to the friction cut member 51 via 65, and is connected to the first connection jig 11 having the first jack support pressure portion 13 at the other end and the steel end member 65 of the first connection jig 11. On the opposite side of the second jack supporting portion 14 with the second jack supporting portion 14 disposed between the one end portion 11a and the first jack supporting portion 13 and the first jack supporting portion 13 interposed therebetween. A second connection jig 12 formed by connecting the tie rod fastening portion 15 to be arranged with a rod member 16 that penetrates the first jack support pressure portion 13 in a loosely fitted state, and a first jack support pressure of the first connection jig 11. Part 13 and the second jack of the second connecting jig 12 The hydraulic jack 17 is provided between both ends of the pressure-supporting portion 14 joined to each other, and by extending the hydraulic jack 17, the tie rod fastening portion 15 is drawn toward the friction cut member 51 to the tie rod member 61. A predetermined tension is applied.

  As shown in FIGS. 3 and 4, the first connection jig 11 integrally connects the joining plate 18 at one end portion 11 a and the first jack support portion 13 at the other end portion by a pair of side plates 19 on both sides. The hollow part for arrange | positioning the hydraulic jack 17 while slidably moving the 2nd jack supporting pressure part 14 of the 2nd connection jig 12 is formed in the inside enclosed by these. The first connecting jig 11 is fixed to the steel end member 65 by the fixing bolt 20 via the joining plate 18 and attached in a state of protruding from the steel end member 65. The first jack support portion 13 of the first connection jig 11 is formed by joining the pair of groove steels 21 with the joint plates 25 on both sides in a state of being overlapped with a gap while facing away from each other. The rod member 16 of the second connecting jig 12 is penetrated in a loosely fitted state via the gap portion of the channel steel 21. In addition, the first connection jig 11 is provided with a jack base 22 that supports the hydraulic jack 17 from below, adjacent to the first jack supporting pressure portion 13, for example, a grooved steel is fixed between the pair of side plates 19. Is provided by. Further, a pair of first slide rails 23 that support the second jack supporting portion 14 of the second connection jig 12 so as to be slidable from below are provided on the bottom surface portion of the first connection jig 11, for example, an angle steel is a jack base 22. And the connecting plate 18 by being installed and fixed. In addition, a pair of second slide rails 24 that slidably support the tie rod fastening portion 15 of the second connection jig 12 from below is formed by projecting, for example, angle steel from the first jack support pressure portion 13 in a cantilever shape. It is attached by fixing.

  The 2nd connection jig 12 connects the 2nd jack bearing pressure part 14 of one end, and the tie rod fastening part 15 of the other end with the rod member 16 which penetrates the 1st jack bearing pressure part 13 in a loose fitting state. Consists of. The second jack bearing section 14 is formed by joining the pair of groove steels 26 with the joining plates 27 on both sides in a state where the pair of groove steels 26 face each other while being overlapped with each other. By inserting the rod member 16 into the portion and fixing the rod member 16 from both sides with, for example, fixing nuts 28, the second jack supporting portion 14 is fixed to one end portion of the rod member 16. The tie rod fastening portion 15 is formed by joining the pair of groove steels 29 with the joint plates 30 on both sides in a state of being overlapped with a gap while facing away from each other. The tie rod fastening portion 15 is fixed to the other end portion of the rod member 16 by inserting the rod member 16 and fixing the rod member 16 from both sides with, for example, fixing nuts 28. The other end portion of the tie rod member 61 is inserted into the central portion of the tie rod fastening portion 15 through the space between the pair of channel steels 29, and the other end portion of the tie rod member 61 is connected to the tie rod fastening nut 31. Is fastened and fixed to the tie rod fastening portion 15 by using. Accordingly, the other end of the tie rod member 61 is connected and fixed to the friction cut member 51 via the tension adjusting device 10 and the steel end member 65.

  As the hydraulic jack 17 provided between the first jack support portion 13 and the second jack support portion 14, various known hydraulic jacks used for propulsion work, shield work, etc. can be used. For example, a pressure of about 300 KN is used. It has the ability and has a stroke length of about 40 cm, for example. The hydraulic jack 17 includes a pressure gauge so that the tension of the tie rod member 61 loaded by the extension of the hydraulic jack 17 can be measured. By extending the hydraulic jack 17 and pushing out the second jack support pressure portion 14 of the second connecting jig 12 in the propulsion direction X, the tie rod tightening portion 15 is pulled in the propulsion direction X, and the tie rod tightening portion 15 It becomes possible to eliminate the slack of the tie rod member 61 whose end is fastened and to apply tension or increase the tension. By contracting the hydraulic jack 17 and pulling the second jack bearing pressure portion 14 in the direction opposite to the propulsion direction X, the tie rod fastening portion 15 is moved in the direction opposite to the propulsion direction X and is loaded on the tie rod member 61. It is possible to reduce the tension, and to remove the other end of the tie rod member 61 from the tie rod fastening portion 15 as necessary.

  Moreover, in this embodiment, the rod member 16 which connects the 2nd jack supporting pressure part 14 and the tie rod fastening part 15 of the 2nd connection jig 12 equips the outer peripheral surface with the external thread part 32 over the substantially full length. The first nut member 33 is screwed to a portion between the first jack supporting pressure portion 13 and the second jack supporting pressure portion 14 of the rod member 16 made of the bolt member. . When the hydraulic jack 17 is extended and a predetermined tension is applied to the tie rod member 61, the first nut member 33 is fastened to the first jack supporting pressure portion 13, so that the operation of the hydraulic jack 17 is stopped. It becomes possible to easily maintain a state in which a predetermined tension is applied to the tie rod member 61. Further, the second nut member 34 screwed into the portion between the first jack support pressure part 13 and the tie rod fastening part 15 is connected to the first jack support pressure part 13 from the opposite side of the first nut member 33. By tightening the first jack support pressure portion 13 so as to be sandwiched, the state where a predetermined tension is applied to the tie rod member 61 can be held in a more stable state.

  According to the construction method of the underground passage of the present embodiment, the underground passage outer structure 56 is additionally disposed by sequentially overlapping the spacer members 63 and 64 in the propulsion direction X between the main push jack 58 and the reaction force wall 62. The tie rod member 61 connected and fixed to the friction cut member 51 is propelled in the propulsion direction X while preventing the friction cut member 51 from co-moving. That is, when the underground passage outer structure 56 is advanced by the stroke of the main pushing jack 58, the tension of the tie rod member 61 is loosened, the tie rod member 61 at the work location is once removed, and the spacer 63 and the strut 64 are pushed behind the jack 58. Place additional. Thereafter, the tie rod member 61 is connected and stretched again, and the hydraulic jack 17 of the tension adjusting device 10 is extended to apply a predetermined tension to the tie rod member 61, and then the main push jack 58 is extended to extend the underground passage outline structure. The body 56 is advanced again. By repeating such a process, the planned underpass 50 is replaced with the pipe roof 55 and installed in the planned underpass 50.

  Here, when restarting the propulsion operation of the subway outer shell structure 56, the predetermined tension applied to each tie rod member 61 by the tension adjusting device 10 causes the friction cut member 51 to start the vertical shaft 53 by the pulling action of the tie rod member 61. However, the friction cut member 51 including the weight of the friction cut member 51 at least can be appropriately set within a range in which the co-movement of the friction cut member 51 can be effectively prevented. The number of tie rod members 61 (shown in FIG. 1) is a value obtained by multiplying the acting load by the friction coefficient (for example, 0.35) between the underpass outer structure 56 (for example, concrete) and the friction cut member 51 (for example, steel). In this embodiment, it is preferable that the tension is a value divided by 5). And even more preferably to a correct value of tension. That is, the total tension T borne by the five tie rod members 61 is expressed as follows, where a is a coefficient of friction between the subway outer structure 56 and the friction cut member 51, and W is an upper load acting on the friction cut member 51. T = a × W is preferable. By setting the predetermined tension applied to the tie rod member 61 when restarting the propulsion operation of the underpass outer shell structure 56 to such a value, the friction cut member 51 can be moved together as the underpass outer shell structure 56 advances. It becomes possible to prevent reliably. Moreover, it becomes easy to manage the tension.

According to the present embodiment, when the tie rod member 61 is re-stretched, a predetermined tension is easily and surely applied to the tie rod member 61, and the frictional force between the friction cut member 51 and the subway outer structure 56 is obtained. Thus, it is possible to effectively prevent the friction cut member 51 from co-moving in the propulsion direction X of the underground passage outline structure 56. That is, according to the present embodiment, after the tie rod member 61 is temporarily removed and the spacer members 63 and 64 are additionally installed, when the tie rod member 61 is re-stretched and the propulsion work of the underground passage outline structure 56 is resumed, After a predetermined tension is applied to the tie rod member 61 by the tension adjusting device 10, the propulsion work of the underground passage outline structure 56 is performed. Therefore, for example, the bolts at the fixing portion of the tie rod member 61 to the reaction force wall 62 are tensioned, the coupler connecting the tie rod member 61 is tightened, and the tie rod member 61 is supported from below without requiring a difficult and labor-intensive operation. By simply operating the hydraulic jack 17 of the tension adjusting device 10, the bending of the tie rod member 61 can be easily eliminated or a predetermined tension can be applied to the tie rod member 61, so that the friction cut member 51 can be moved. It becomes possible to efficiently obtain the supporting force necessary for prevention from the reaction force wall 62 every time the propulsion work is restarted, whereby the friction cut member 51 moves together in the propulsion direction X of the underground passage outline structure 56 Can be effectively prevented.

The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the tension adjusting device is not limited to the tension adjusting device having the above-described configuration including a first connecting jig, a second connecting jig, and a hydraulic jack, and includes various other types of hydraulic jacks including a pressure gauge. It is possible to employ a tension adjusting device having the following structure. Further, the tension adjusting device does not necessarily have to be attached to the connecting portion of the other end portion of the tie rod member to the friction cut member, and can be used by being attached to other portions of the tie rod member.

It is a principal part top view of the part of the start shaft explaining the construction method of the underground passage which concerns on preferable one Embodiment of this invention. It is a principal part top view explaining the structure of the tension adjusting device which concerns on preferable one Embodiment of this invention. It is sectional drawing in alignment with AA of FIG. 2 explaining the structure of the tension | tensile_strength adjustment apparatus which concerns on preferable one Embodiment of this invention. It is sectional drawing along BB of FIG. 2 explaining the structure of the tension | tensile_strength adjustment apparatus which concerns on preferable one Embodiment of this invention. (A) to (j) form an underground passage according to a preferred embodiment of the present invention by replacing the pipe roof formed in the ground with an underground passage outline structure with the friction cut member left in the ground. It is the longitudinal cross-sectional view and horizontal cross-sectional view explaining the process of the construction method of the underground passage which does.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tension adjusting device 11 1st connection jig 11a One end part 12 of a 1st connection jig 2nd connection jig 13 1st jack bearing pressure part 14 2nd jack bearing pressure part 15 Tie rod fastening part 16 Rod member (bolt member)
17 Hydraulic jack 18 Joint plate 33 First nut member (nut member)
50 Planned underground passage 51 Friction cut member 52 Box-shaped pipe member 53 Starting shaft 54 Reaching shaft 55 Pipe roof 56 Underpass outer structure 58 Main jack 60 Underpass 61 Tie rod member 62 Reaction wall 63 Spacer (spacer member)
64 strut (spacer member)
65 Steel end material X Propulsion direction

Claims (4)

A plurality of box-shaped pipe members including a box-shaped pipe member in which a friction cut member is fixed to a surface arranged along the upper surface of the rectangular cross-section of the planned underground passage section are arranged in parallel at least at the upper floor position of the planned underground passage section. After forming the pipe roof penetrating through the planned underground passage portion in the ground, the end surface of the underground passage outline structure having a rectangular cross section is brought into contact with the end surface of the pipe roof, and the tip of the underground passage outline structure While excavating the sand and sand of the face of the bottom of the underpass, the underpass structure is propelled from the start shaft by a pushing jack, and the friction cut member released from fixing with the box-shaped pipe member is left in the ground, By constructing an underground passage by forming the underground passage by the underground passage structure in the planned underground passage portion by extruding the pipe roof and replacing it with the underground passage outline structure. In the method,
The underpass outer structure is propelled while additionally arranging a spacer member in the propulsion direction sequentially between the main push jack and the reaction wall of the start shaft, and the friction cut member is the start shaft The underpass is supported by the tension of a tie rod member whose one end is supported and fixed to the reaction force wall and the other end is connected and fixed to the friction cut member with a tension adjusting device including a hydraulic jack provided with a pressure gauge interposed therebetween. As the outer structure is propelled, it is prevented from moving together.
After adding placing the spacer member and disconnect the tie rod member once, when re-stretched the tie rod member resuming promote work of the underpass shell structure, said tie rod member by the tension adjusting device, After the tension cut of the tie rod member does not pull the friction cut member to the start shaft side, and after applying a predetermined tension within a range in which the friction cut member can be prevented from co-moving, the propulsion work of the underground passage outline structure A method for constructing an underpass characterized by including a step of performing   The predetermined tension applied to the tie rod member by the tension adjusting device is applied to at least an overlay load acting on the friction cut member including a weight of the friction cut member, and the underground passage outline structure and the friction cut member 2. The method for constructing an underground passage according to claim 1, wherein the tension is a value obtained by dividing a value obtained by multiplying the coefficient of friction by the number of tie rod members. A tension adjusting device provided in a connecting portion to the friction cut member at the other end of the tie rod member used in the method for constructing an underpass according to claim 1 or 2,
A first connection jig having one end connected to and fixed to the friction cut member and a first jack support pressure part at the other end, and between the one end of the first connection jig and the first jack support pressure part A second jack bearing pressure portion disposed; and a tie rod fastening portion disposed on the opposite side of the second jack bearing pressure portion across the first jack bearing pressure portion; Joining both ends to a second connecting jig connected by a rod member penetrating in a loosely fitting state, a first jack supporting section of the first connecting jig, and a second jack supporting section of the second connecting jig It consists of a hydraulic jack provided between them,
A tension adjusting device that stretches the hydraulic jack to draw the tie rod fastening portion toward the friction cut member and applies a predetermined tension to the tie rod member.   The rod member that connects the second jack supporting portion and the tie rod fastening portion of the second connecting jig is constituted by a bolt member having a male screw portion, and the first jack supporting portion of the bolt member; A nut member is screwed to a portion between the second jack support pressure portion, and when the hydraulic jack is extended and a predetermined tension is applied to the tie rod member, the nut member is supported by the first jack support. The tension adjusting device according to claim 3, wherein a state in which a predetermined tension is applied to the tie rod member is maintained by being fastened to the pressure portion.

Images