JP2008127834A - Tunnel interior construction method and precast floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tunnel interior construction method which facilitates adjustment of a cant and a height of a road floor slab in a curved section and a clothoid section of a tunnel. <P>SOLUTION: According to the method, a plurality of additional brackets 5 is set on a side wall bracket 1a on an external course side of the tunnel curved section, so as to form an ascending gradient in a tunnel axial direction, and the additional brackets 5 are set on the side wall bracket 1a on an internal course side of the tunnel curved section, so as to form a descending gradient in a tunnel axial direction. Then a bearing portion 3a is set at an end on the external course side of the precast floor slab 3, so as to form the ascending gradient in the tunnel axial direction and borne by the additional brackets 5 on the external course side, and a bearing portion 3b is set at an end on the internal course side of the precast floor slab 3, so as to form the descending gradient in the tunnel axial direction and borne by the additional brackets 5 on the internal course side. Further an upper surface of the precast floor slab 3 is formed into a twisted surface so as to continuously connect between the end on the external course side forming the ascending gradient in the tunnel axial direction and the end on the internal course forming the descending gradient. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a construction method inside a tunnel and a precast slab used as a road slab in the construction method inside the tunnel, and in particular, a cant of a curved portion of a tunnel including a clothoid portion (entrance / exit portion of a curved portion). The inclination in the transverse direction) and the adjustment in the height direction can be performed without using the adjustment concrete, and pavement can be performed with the precast slab as it is laid.

  The shield tunnel dug mainly for roads and lifelines, for example, as shown in FIG. 10, an upper space A used as a roadway with a road deck 20 constructed almost near the center of the tunnel as a boundary, drainage The lower space B is used as a maintenance facility such as electricity or as an evacuation facility. The lower space B is further divided into a plurality of spaces by the inner wall 21 as necessary.

  Moreover, each part, such as the above-mentioned road floor slab 20 and the inner wall 21, is constructed by a precast concrete member in order to save labor and shorten the construction period.

  By the way, for road decks at the curved and clothoid parts of the tunnel, the cant (inclination in the transverse direction of the curve) and the height direction are adjusted so that the vehicle can run smoothly while resisting the centrifugal force caused by the curve. ing.

  Conventionally, this cant and height adjustment is performed by using a normal precast slab in the curved part and clothoid part, as shown in the figure, using a normal precast slab as well as on the left and right sides of the floor slab. Without changing the height, the adjustment concrete 22 was cast on the road floor slab 20 and the thickness of the adjustment concrete 22 was changed.

JP-A-5-133193 JP-A-5-133194 JP 2002-89195 A JP 2003-64994 A JP 2004-285758 A

  However, the adjustment with cast-in-place concrete is difficult to take the slope and is troublesome to construct, and also requires a period for curing the concrete. There were problems such as inevitable.

  The present invention has been made in order to solve the above problems, and in particular, it is possible to easily adjust the cantilever and height direction of the road floor slab of the tunnel curved portion including the clothoid portion without using adjustment concrete. It is an object of the present invention to provide a construction method inside a tunnel and a precast slab used in the construction method.

  The precast slab according to claim 1 is provided with a bracket projecting upwardly in the axial direction of the tunnel on the inner side on the outer course side of the tunnel curved portion, and on the inner side on the inner course side of the tunnel curved portion. A precast floor slab installed between brackets projecting downwardly in the axial direction of the tunnel, in the axial direction of the tunnel along the outer course side bracket at the outer course side end Protruding with an ascending slope, provided with a support portion supported by the bracket on the outer course side, and having a descending slope in the axial direction of the tunnel along the inner course side bracket at the inner course end. None, provided with a support portion supported by the bracket on the inner course side, and between the end on the outer course side where the upper surface forms an upward gradient in the axial direction of the tunnel and the end on the inner course side which forms a downward gradient Communicating And it is characterized in that so as twisted are formed on the surface to.

  The present invention has an upward slope in the axial direction of the tunnel at the end on the outer course side of the tunnel, a support portion supported by the bracket on the outer course side is provided, and the end on the inner course side of the tunnel A downward slope is formed in the axial direction of the tunnel, a support portion supported by the bracket on the inner course side is provided, and an inner surface forming a downward slope with an end portion on the outer course side that forms an upward slope in the axial direction of the tunnel. By forming it on a twisted surface that is continuous between the ends on the course side, only the upper surface is formed on the twisted surface, and the portion below it is formed in a flat plate shape like a normal precast slab Thus, a precast floor slab can be easily molded.

  The construction method for the inside of the tunnel according to claim 2 is such that the outer course side natural ground and the inner course side natural ground of the tunnel curve portion are respectively covered by a side wall bracket integrated segment having a side wall bracket, A tunnel internal construction method in which a precast floor slab is installed between a side wall bracket and a side wall bracket on the inner course side to construct the inside of the curved curve portion, and the ascending slope in the axial direction of the tunnel on the outer side wall bracket A plurality of extension brackets are installed so as to form a slope, a plurality of extension brackets are installed on the inner course side wall bracket so as to form a downward slope in the axial direction of the tunnel, and the end of the precast floor slab on the outer course side An upward slope is formed in the axial direction of the tunnel along the extension bracket on the outer course side, and is supported by the extension bracket on the outer course side. A support is provided, and the end of the precast floor slab is inclined downward along the inner course side extension bracket along the inner course side extension bracket, and is supported by the inner course side extension bracket. And an upper surface of the precast slab is formed on a surface twisted so as to be continuous between an end portion on the outer course side that forms an upward gradient in the axial direction of the tunnel and an end portion on the inner course side that forms a downward gradient. It is characterized by doing.

  In the present invention, an extension bracket is installed on the side wall bracket projecting inside the segment installed on the outer course side of the tunnel curved portion so as to form an upward slope in the axial direction of the tunnel, and the inner course of the tunnel curved portion is provided. Install an additional bracket on the side wall bracket that protrudes inside the segment installed on the side so as to form a downward slope in the axial direction of the tunnel, and the upper surface of the precast slab installed between the additional brackets By forming the surface to be twisted so as to be continuous between the extension brackets, it is possible to easily adjust the cantilever and height direction of the road floor slab in the tunnel curve part and clothoid part without using adjustment concrete. It is.

  The construction method for the interior of the tunnel according to claim 3 is the construction method for the interior of the tunnel according to claim 2, wherein the additional bracket on the outer course side has an upward slope in the axial direction of the tunnel, and the outer course side of the precast floor slab The rail beam that supports the end of the rail and the height adjustment device that adjusts the gradient of the rail beam are installed, and the extension bracket on the inner course side has a downward slope in the axial direction of the tunnel, and the inner course side of the precast slab A rail beam that supports the end of the rail beam and a height adjusting device that adjusts the gradient of the rail beam are installed, and particularly cant and fine adjustment in the height direction can be easily performed.

  The construction method for the inside of the tunnel according to claim 4 is a method of covering the ground on the inner course side and the ground on the outer course side of the tunnel curved portion with a side wall bracket integrated segment having a side wall bracket, respectively, And a tunnel construction method in which a precast floor slab is installed between the side wall brackets on the outer course side to construct the inside of the tunnel curved portion, and the inner course side end of the precast floor slab is connected to the inner course side wall. The end portion on the outer course side of the precast slab is installed on the side wall bracket on the outer course side via an additional bracket.

  The construction method for the interior of the tunnel according to claim 5 is the construction method for the interior of the tunnel according to claim 4, wherein the rail bracket that supports the other end of the precast slab is attached to the extension bracket installed on the other side wall bracket. A height adjusting device for adjusting the gradient of the rail beam is installed.

  Note that the precast slabs adjacent to each other in the tunnel axial direction can be joined by a long bolt or a PC steel rod. In this case, a plurality of precast slabs adjacent in the axial direction of the tunnel can be joined simultaneously or one by one.

  Further, a shear key can be provided on the joint surface of the precast slab. Examples of the shear key in this case include irregularities formed integrally with the precast floor slab on the joint surface of the precast floor slab, or a steel bar interposed on the joint surface.

  The precast floor slab according to claim 6 is installed between side wall brackets that protrude upwardly in the axial direction of the tunnel on the inner side on the outer course side and the inner side on the inner course side of the curved curve portion. A precast floor slab having an upward slope in an axial direction of the tunnel along the side wall bracket at an end on the outer course side and an end on the inner course side, and a support portion supported by the side wall bracket. And the upper surface of the precast slab is formed so as to be continuous between an end portion on the outer course side that forms an upward gradient in the axial direction of the tunnel and an end portion on the inner course side that forms a downward gradient. It is a feature.

  The present invention is a precast slab that is used when both the outer course side and the inner course side of the tunnel curved portion have an ascending slope (or a descending slope).

  The construction method for the inside of the tunnel according to claim 7, wherein the outer course side ground mountain and the inner course side ground mountain of the tunnel curved portion are respectively covered by a side wall bracket integrated segment having a side wall bracket, It is a construction method inside a tunnel in which a precast floor slab is installed between a side wall bracket and a side wall bracket on the inner course side to construct the inside of the tunnel curved portion, and the side wall bracket on the outer course side and the side wall bracket on the inner course side A plurality of extension brackets are respectively installed so as to form an upward slope in the axial direction of the tunnel, and the tunnel axis is extended along the extension bracket to the end on the outer course side and the end on the inner course side of the precast floor slab. An upward slope is formed in the direction, a support portion supported by the extension bracket is provided, and the upper surface of the precast floor slab is provided on the tunnel. It is characterized in that formed inside so as to be continuous between the ends of the course side forming the end portion and the downward slope of the outer course side forming a gradient rising in the axial direction.

  The present invention is a construction method for the inside of a tunnel used when both the outer course side and the inner course side of the tunnel curved portion have an upward slope (or downward slope).

  The tunnel internal construction method according to claim 8 is the tunnel internal construction method according to claim 7, wherein the outer course side extension bracket and the inner course side extension bracket have an upward slope in the tunnel axial direction, and are precast. A rail beam that supports an end portion on the outer course side and an end portion on the inner course side of the floor slab, and a height adjusting device that adjusts the gradient of the rail beam are installed.

  When constructing a curved tunnel or clothoid road of a shield tunnel by laying a precast floor slab, the present invention projects the side wall bracket protruding from the inner side of the tunnel at the same height as the straight part of the tunnel. Even with this, the cantilever of the road floor slab and the adjustment in the height direction can be easily performed.

  For example, when building a road with an ascending slope on the outer course side of the tunnel curve and a descending slope on the inner course side by laying a plurality of precast slabs, side wall brackets projecting inside the outer course segment Multiple extension brackets are installed so as to have an upward slope in the tunnel axis direction, and multiple extension brackets are installed on the side wall bracket protruding inside the inner course side segment so as to have a downward slope in the tunnel axis direction. The precast floor slab has an upward slope in the tunnel axis direction at the end on the outer course side, a support portion supported by the bracket on the outer course side is provided, and the end on the inner course side is lowered in the axial direction of the tunnel. Form a slope, provide a support portion supported by the bracket on the inner course side, and continue the upper surface of the precast slab between the additional brackets It can be readily constructed by forming the Flip the surface.

  In addition, the extension bracket on the outer course side has an upward slope in the axial direction of the tunnel, a rail beam that supports the end of the precast floor slab on the outer course side, and a height adjustment device that adjusts the slope of the rail beam. Install a rail beam that supports the end on the inner course side of the precast floor slab and a height adjustment device that adjusts the gradient of the rail beam on the extension bracket on the inner course side in the tunnel axial direction. By installing, canting of the curved portion and fine adjustment in the height direction can be easily performed.

  FIG. 1 shows the inside of a curved portion or clothoid portion of a shield tunnel (hereinafter referred to as “tunnel”) constructed for road use, and FIG. 2 shows the inside of a straight tunnel portion. In FIG. 2, the grounds on both sides of the tunnel are covered with bracket-integrated segments (hereinafter referred to as “segments”) 1 each having a side wall bracket 1a inside.

  An invert composed of a plurality of precast concrete inverts 2 (hereinafter referred to as “precast invert 2”) is constructed at the bottom of the tunnel, and a floor slab composed of a plurality of precast floor slabs 3 is constructed in the middle part. An intermediate wall composed of a plurality of precast concrete intermediate walls 4 (hereinafter referred to as “precast intermediate walls 4”) is constructed between the precast floor slab 3. Thus, the inside of the tunnel is divided into an upper space A and a lower space B by a floor slab, and the lower space B is divided into two left and right spaces by the middle wall 4.

  The side wall bracket 1a is formed so as to serve as a side wall of the lower space B integrally with the segment 1 when the segment 1 is molded. In addition, the said side wall bracket 1a may be formed separately from the segment 1, and may be retrofitted to the inner side part of the segment 1 by methods, such as bolting. If the side wall bracket 1a is retrofitted, the height of the side wall bracket 1a due to rolling or meandering of the segment 1 can be easily corrected.

  In particular, on the outer course side and inner course side of the curved portion and clothoid portion of the tunnel, as shown in FIGS. 3 to 5, the extension brackets are provided on the side wall brackets 1a on the outer course side and the inner course side of the tunnel. 5 is installed, and the height adjustment device 6 for adjusting the cantilever of the precast floor slab 3 and the height direction is installed on the extension bracket 5 at predetermined intervals in the axial direction of the tunnel.

  The extension brackets 5 are basically formed from precast concrete such as fiber reinforced mortar, and are installed one by one for each segment. Further, each extension bracket 5 installed on the side wall bracket 1a on the outer course side of the tunnel is gradually formed so as to form an uphill staircase shape in the tunnel axial direction as shown in FIG. 3B. On the other hand, although not particularly shown, each extension bracket 5 installed on the inner course side wall bracket 1a is formed so as to be gradually lowered so as to form a stepped downward slope in the axial direction of the tunnel. Yes.

  As shown in FIGS. 4 and 5, the height adjusting device 6 includes a plurality of vertical bolts 7, 7 protruding on the extension bracket 5 at a predetermined interval in the width direction of the extension bracket 5 and the vertical bolt. The receiving beam 8 spanned between the bolts 7 and 7 and the vertical bolts 7 and 7 are screwed together, and the height of the receiving beam 8 is adjusted by moving the receiving beam 8 in the vertical direction. Is composed of a plurality of fixing nuts 9 and 9 for fixing the bolts to the vertical bolts 7 and 7.

  A rail beam 10 continues along the axial direction of the tunnel between the receiving beams 8 and 8 installed on the outer course side of the tunnel and between the receiving beams 8 and 8 installed on the inner course side of the tunnel. It is overlaid.

  The rail beam 10 installed on the outer course side of the tunnel has an upward slope in the axial direction of the tunnel, and is continuously bridged in the axial direction of the tunnel. The rail beam 10 installed on the inner course side of the tunnel is A downward slope is formed in the axial direction of the tunnel, and it is continuously stretched in the axial direction of the tunnel. In this case, the gradient of the rail beam 10 can be set to an arbitrary gradient by turning the fixing nuts 9 and 9 to move the receiving beams 8 up and down.

  The precast invert 2 is laid adjacent to each other in the axial direction of the tunnel at the bottom of the tunnel, and each precast invert 2 is fixed to the segment by a plurality of anchor bolts 11. In this case, the level of each precast invert 2 is adjusted simultaneously by the anchor bolt 11, and the adjusted mortar is filled between the adjusted precast invert 2 and the segment 1.

  In the center of the precast invert 2, a recess 2a for erected the lower end of the precast middle wall 4 is formed continuously in the axial direction of the tunnel, and the lower end surface of the precast invert 2 is the inner periphery of the segment. A convex curved surface is formed along the surface.

  The precast floor slab 3 is formed in a rectangular plate shape elongated in the transverse direction of the tunnel, and the rail beam 10 on the outer course side of the precast floor slab 3 is provided on the outer course side end and the inner course side end of the tunnel, respectively. A support part 3a and a support part 3b, which are placed on and supported by the rail beam 10 on the inner course side, are formed.

  The outer course side support portion 3a is formed with an upward slope along the outer course side rail beam 10, and the inner course side support portion 3b is formed with a downward slope along the inner course side rail beam 10. .

  Further, the upper surface of the precast floor slab 3 is formed such that the outer course side end formed on the up course of the outer course side rail beam 10 along the up slope of the outer course side rail beam 10 and the down course of the inner course side rail beam 10. It is formed in the surface twisted so that it may continue between the edge parts of the inner course side formed in the down-slope in the axial direction of the tunnel along the gradient.

  Further, a support portion 3c is formed in the middle portion of the precast floor slab 3 and is placed on and supported by the upper end portion of the precast middle wall 4 via the liner member 12.

  In such a configuration, the cantilever and the height direction of the precast slab 3 are adjusted by turning the fixing nuts 9 of the vertical bolts 7 and 7 and raising and lowering the rail beam 10 via the receiving beam 8. As a result, it is possible to easily adjust the cantilever and height direction of the precast floor slab 3, that is, the road floor slab, in the curved portion and the clothoid portion.

  That is, by raising and lowering both ends of the precast floor slab 3 with the intermediate part of the precast floor slab 3 supported by the precast middle wall 4 as fulcrums, the precast floor slab 3 in the tunnel curve portion and clothoid part, that is, the road floor slab Cant and height adjustment can be easily performed.

  In addition, the vertical bolt 7 in this case is not only retrofitted by being screwed into an insert (not shown) embedded in the extension bracket 5 but can freely set the protruding length of the vertical bolt 7. be able to.

  Further, the extension bracket 5 can be retrofitted by attaching the anchor bolt 13 to an insert (not shown) embedded in the upper end of the side wall bracket 1a in advance.

  The precast floor slabs 3 adjacent to each other in the axial direction of the tunnel are joined to each other by a plurality of super long bolts, long bolts (with a bolt box) or PC steel rods 14.

  In this case, the super long bolt or the PC steel rod 14 is inserted into each precast floor slab 3 from the face of the tunnel toward the wellhead side (see FIG. 8). Further, the end of the extra long bolt or the PC steel rod 14 on the wellhead side is coupled by a method such as screwing into an insert (not shown) embedded in the end of the precast floor slab 3 adjacent to the wellhead side. Then, the end portion on the face side is fixed to the end portion on the face side of the precast floor slab 3 by the fixing nut 15.

  Further, as shown in FIG. 9C, when the precast floor slabs 3 are joined by the long bolts 14 using the bolt boxes 3c, the precast floor slabs 3 are connected by the long bolts 14 drawn from the bolt boxes 3c. Can be joined. In this case, the super long bolt or the PC steel bar 14 is arranged in a so-called staggered manner.

  Note that the central portion of the precast floor slab 3 is formed on the precast wall slab 4 by adjusting support bolts 16 that are vertically installed through the central portion of the precast floor slab 3 as shown in FIG. 6A, for example. Supported by the upper end.

  Since the precast floor slab 3 is supported prior to both ends in construction, the height of the precast floor slab 3 is adjusted with the support bolts 16 for adjustment with respect to the deformation of the center due to its own weight. can do.

  Since the central portion of the precast wall slab 3 is supported in this way, by adjusting the height direction of the precast floor slab 3, only one end of the precast floor slab 3 is supported. It also prevents so-called unilateral effects.

  8 (a) to 8 (d) show other examples of precast slabs, in which the support portion 3a and the support portion 3b are formed to be inclined in the axial direction of the tunnel in accordance with the inclination of the side wall bracket. The upper side is also inclined. Furthermore, the direction perpendicular to the axis (inter-spindle direction) is also formed obliquely in accordance with the axial direction. By forming in this way, the upper surface of the precast floor slab 3 is formed in a state of gradually changing in three dimensions.

  In addition, since the upper surface of the precast floor slab 3 is a finished surface, no special work is required, and the finishing may be performed according to the side mold for floor slab molding.

  In addition, the joint between the precast slabs 3 and 3 adjacent to the tunnel in the axial direction (not shown) requires that the floor slab previously installed and the upper surface of the floor slab to be installed thereafter be aligned with each other. It is provided at a position where the distance is the same. For this reason, the joint on the changing side (face side) is not directly beside but shifted obliquely.

  The mold used for molding the precast floor slab is different from the standard mold as a mold for forming the support portions 3a and 3b because the support portions 3a and 3b of the floor slab 3 are formed obliquely. Formwork is used. In addition, a mold different from the standard mold is used as a mold for molding the face side. Therefore, in the case where both the left and right sides in the axial direction change, a formwork different from the standard formwork is used as a total of five formwork, that is, two faces on the bottom surface of the support portion and three faces on the side formwork.

  The precast middle wall 4 is installed between the precast invert 2 and the precast floor slab 3, and the lower end portion of the precast middle wall 4 is built in the recess 2 a of the precast invert 2.

  Next, the construction procedure of the tunnel interior construction method of the present invention will be described.

  First, precast invert 2 is laid at the bottom of the tunnel. The precast invert 2 is laid at the bottom of the tunnel together with the tunnel lining segment in the tail of the shield machine (not shown). Then, after adjusting the height and level, it is fixed to the segment with anchor bolts 11 and mortar or the like is filled between the segments.

  Next, the precast middle wall 4 is built on the precast invert 2 and the lower end is fixed. In this case, the lower end portion of the precast middle wall 4 is built in the recess 2 a of the precast invert 2.

  Further, the extension bracket 5 and the height adjusting device 6 are installed on the upper end portion of the side wall bracket 1a, and the rail beam 10 is bridged on the receiving beam 8 of the height adjusting device 6. Then, the height and gradient of the rail beam 10 are adjusted by turning the fixing nut 9 and raising and lowering the rail beam 10 together with the receiving beam 8.

  Next, the precast floor slab 3 is bridged between the upper end portion of the precast middle wall 4 and the rail beams 10 on both sides.

  Further, the precast floor slab 3 is joined to the existing precast floor slab 3 installed on the face of the tunnel with a super long bolt or a PC steel bar 16.

  Similarly, the precast invert 2, the precast middle wall 4 and the precast floor slab 3 are sequentially installed in the tunnel excavation direction to construct the invert, the floor slab and the middle wall in the tunnel.

  FIG. 10 shows another example of the present invention, in which the end of the inner course side of the precast floor slab 3 is pivotally supported on the side wall bracket 1a by the rotation pin 17 so as to be rotatable in the vertical direction. The end on the course side is supported on the side wall bracket 1a via the extension bracket 5 and the height adjusting device 6 as shown in FIG. 4 (a).

  In the present invention, the road floor slab cant (gradient in the transverse direction of the road floor slab) and the height direction of the tunnel curved part and clothoid part are adjusted, and the road floor slab is paved, and the side wall bracket is the same height as the straight part. Can be easily done without using adjusting concrete.

It is a longitudinal cross-sectional view which shows the structure inside the curve part or clothoid part of a tunnel. It is a longitudinal cross-sectional view which shows the structure inside the linear part of a tunnel. (A), (b) is respectively the II line enlarged sectional view in FIG. 1, and the ROLL line enlarged sectional view. FIG. 2A is an enlarged cross-sectional view of a portion C in FIG. 1, and FIG. 2B is an enlarged cross-sectional view of a portion 2 in FIG. A height adjustment apparatus is shown, (a) is a front view, (b) is a top view. (A) is a longitudinal cross-sectional view which shows the junction part of a precast floor slab and a precast concrete intermediate wall, (b) is a longitudinal cross-sectional view which shows the state which laid precast invert. (A) is a perspective view of a precast slab, (b) is a front view of the precast slab as viewed in the tunnel axial direction, (c) is a side view of the precast slab, and (d) is a plurality of precast laying It is a side view of a floor slab. (A) is a perspective view of a precast slab, (b) is a front view seen in the tunnel axial direction of the precast slab, and (c) and (d) are side views of the precast slab. (A) is a perspective view of a precast floor slab, (b), (c) is a longitudinal sectional view showing a joint portion of the precast floor slab. It is a longitudinal cross-sectional view which shows the structure inside the curve part or clothoid part of a tunnel. It is a longitudinal cross-sectional view which shows the structure inside the curve part or clothoid part of the conventional tunnel.

Explanation of symbols

1 Bracket-integrated segment 1a Side wall bracket 2 Precast invert 3 Precast floor slab 4 Precast inner wall 5 Additional piece 6 Height adjustment device 7 Vertical bolt 8 Receiving beam 9 Adjustment nut 10 Rail beam 11 Anchor bolt 12 Liner member 13 Anchor bolt 14 Long bolt or PC steel bar 15 Fixing nut

Claims (8)

  A bracket projecting with an upward slope in the axial direction of the tunnel on the inner side on the outer course side of the tunnel curved portion, and a downward slope in the axial direction of the tunnel on the inner course side of the tunnel curved portion Precast floor slabs installed between brackets protruding in a projecting manner and projecting at an end on the outer course side with an upward slope in the axial direction of the tunnel along the bracket on the outer course side. A support portion supported by the bracket on the course side is provided, and an end portion on the inner course side has a downward slope in the axial direction of the tunnel along the bracket on the inner course side, and is supported by the bracket on the inner course side. And the upper surface is formed on a surface twisted so as to be continuous between the end portion on the outer course side that forms an upward gradient in the axial direction of the tunnel and the end portion on the inner course side that forms a downward gradient. Na Precast slab, characterized in that.   The ground course on the outer course side and the ground course on the inner course side of the tunnel curve part are respectively covered with a side wall bracket integrated segment having side wall brackets, and a precast floor is provided between the outer course side and inner side wall side brackets. It is a construction method inside the tunnel that installs a plate to construct the inside of the tunnel curve part, and installs a plurality of additional brackets so as to form an upward gradient in the axial direction of the tunnel on the side wall bracket on the outer course side, A plurality of extension brackets are installed on the inner course side wall bracket so as to have a downward slope in the axial direction of the tunnel, and along the outer course side extension bracket at the outer course end of the precast slab. An upward slope is formed in the axial direction of the tunnel, and a support portion supported by the extension bracket on the outer course side is provided, and the inside of the precast floor slab is provided. A slope in the axial direction of the tunnel along the inner course side extension bracket at the end of the first course side, a support portion supported by the inner course side extension bracket is provided, and the precast slab The construction of the inside of the tunnel, characterized in that the upper surface is formed in a surface twisted so as to be continuous between the end portion on the outer course side forming an upward gradient in the axial direction of the tunnel and the end portion on the inner course side forming a downward gradient. Construction method.   The extension bracket on the outer course side has an upward slope in the axial direction of the tunnel, and a rail beam that supports the end of the precast floor slab on the outer course side and a height adjustment device that adjusts the gradient of the rail beam are installed. The inner bracket side extension bracket has a downward slope in the axial direction of the tunnel, and a rail beam that supports the inner course side end of the precast floor slab and a height adjusting device that adjusts the gradient of the rail beam are installed. The construction method for the inside of a tunnel according to claim 2, wherein:   The ground course on the inner course side and the ground course on the outer course side of the tunnel curve section are respectively covered with side wall bracket integrated segments having side wall brackets, and the precast floor is between the inner course side and outer course side wall brackets. A tunnel interior construction method in which a plate is installed to construct the inside of a curved curve portion, and one end portion of the inner course side or outer course side of the precast floor slab is rotatably supported on one side wall bracket. And the other end part of the said precast slab is installed in the other side wall bracket via an extension bracket, The construction method inside a tunnel characterized by the above-mentioned.   5. A rail beam supporting the other end of the precast floor slab and a height adjusting device for adjusting the gradient of the rail beam are installed on the additional bracket installed on the other side wall bracket. Construction method inside the tunnel.   A precast floor slab installed between side wall brackets protruding upwardly in the axial direction of the tunnel on the inner side on the outer course side and the inner side on the inner course side of the curved curve portion, And an end portion on the inner course side, an upward slope is formed in the axial direction of the tunnel along the side wall bracket, and a support portion supported by the side wall bracket is provided, and an upper surface of the precast slab The precast slab is formed so as to be continuous between an end portion on the outer course side forming an upward gradient in the axial direction of the tunnel and an end portion on the inner course side forming a downward gradient.   The ground course on the outer course side and the ground course on the inner course side of the tunnel curve part are respectively covered with a side wall bracket integrated segment having side wall brackets, and a precast floor is provided between the outer course side and inner side wall side brackets. A tunnel internal construction method in which a plate is installed to construct the inside of the tunnel curved portion, and a plurality of so as to form an upward slope in the axial direction of the tunnel on the outer course side wall bracket and the inner course side wall bracket. Each of the additional brackets is installed, and the end on the outer course side and the end on the inner course side of the precast slab form an upward slope in the axial direction of the tunnel along the extension bracket, and is supported by the extension bracket. And an end portion on the outer course side where the upper surface of the precast slab is inclined upward in the axial direction of the tunnel. Tunnel interior construction method, which comprises forming the inner so as to be continuous between the ends of the course side forming a downward slope.   Rail beams that support the outer course end and the inner course end of the precast floor slab on the outer course side extension bracket and the inner course side extension bracket. And a height adjusting device for adjusting the gradient of the rail beam is installed.

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