JP4915290B2 - Sidewall tunnel construction method and structure - Google Patents

Description

  The present invention relates to a method for constructing a side wall tunnel and its structure, and more particularly to an improved technique for a side tunnel that greatly shortens the construction period and reduces the construction cost.

  Conventionally, a side tunnel type tunnel construction method is known as a construction method of a large-section tunnel that needs to prevent ground subsidence in a earth and sand mountain with insufficient ground support force or a small earth covering. 5 to 10 show a tunnel construction method by the side wall tunnel type tunnel construction method, and FIG. 5 is a schematic plan view showing a state during the construction. Moreover, FIGS. 6-10 is sectional drawing by arrow of each site | part shown by the VI-VI line-XX line in FIG.

  As shown in FIG. 5, in the side wall tunnel 2, a pair of side walls are positioned on both sides of the tunnel main shaft 4 prior to excavation of the tunnel main shaft 4 having a large cross section to be constructed. The guide shafts 6 and 6 are excavated, and the support 7 and the invert 8 are temporarily installed on the inner peripheral surface thereof (see FIG. 6). Then, when the formation of the side wall guide shafts 6 and 6 is completed, a concrete side wall 12 for supporting the supporting work 10 of the tunnel main shaft 4 is next installed in the pair of side wall guide shafts 6 and 6. 6 and 6 are formed along the outer wall surfaces (see FIG. 7). And after the said concrete side walls 12 and 12 harden | cure, excavating the natural ground of the upper part between the side wall shafts 6 and 6 and excavating the upper half part of the tunnel main pit 4 of a large cross section, both concrete side walls 12 and The support work 10 is sequentially installed on the upper part of the inner peripheral surface of the mine, spanning between 12 top ends (see FIG. 8). Thereafter, the lower half of the tunnel main pit 4 is dug between the side wall guide pits 6 and 6, and an invert 14 is formed on the bottom surface thereof (see FIG. 9). After dredging, the arch concrete 16 of the secondary lining body is placed inside the concrete side walls 12 and 12 and the supporting work 10 continuously to the invert 14, and the entire main shaft cross section is formed on the inner peripheral surface of the tunnel main shaft 4. The closed strong lining body 18 is formed to complete the side wall tunnel 2 (see FIG. 10).

  Further, in forming the concrete side wall 12, as shown in FIG. 11, a centle 20, which is a movable steel formwork, is placed to cast concrete, and the concrete side wall 12 is cast over by a predetermined length. ing. Here, in FIG. 11, the centle 20 moves toward the front side of the sheet to form the concrete side wall 12, but as shown in the figure, the centle 20 forms the inner surface portion of the concrete side wall. A steel plate inner surface template 20a, and a steel plate flange template 20b that defines and forms a flange surface to be the next joint surface. And these template 20a, 20b is supported so that the movement stand 21a, 21b which also serves as a work scaffold, respectively can move.

  The traveling platform 21b that supports the buttock formwork 20b travels on the rail 22 that is laid on the base portion 12a of the side wall concrete 12 that is formed in advance by a predetermined length. Is supported on the outer surface side, and the end portion of the inner surface mold 20a is supported. The inner surface form 20a is pressed and supported by a jack 24 via a steel material 23 whose lower end is in contact with the side surface of the base 12a and crosses the side wall guide shaft 6. Is configured to obtain a support reaction force on the inner wall surface on the other side of the side wall guide shaft 6.

  And the traveling frame 21a that supports the inner surface part formwork 20a travels on the rail 25 laid on the steel material 23 in the longitudinal direction of the side wall shaft 6, and the steel material 23 and the jack 24 and Each time the centle 20 is moved to the next concrete side wall forming portion toward the front in the tunnel forming direction, the rail 25 is sequentially moved further to the front portion.

Patent documents relating to such side-wall tunnels include the following publications.
JP-A-8-28191 JP-A-8-184283

  By the way, in the construction method of the above-described conventional side-wall tunnel, the concrete side wall 12 is formed by using the centle 20 which is a movable formwork, and thus has the following problems.

(1) Since the pressing support member composed of the steel material 23 and the jack 24 that press-supports the lower end portion of the inner surface formwork 20a is installed on the invert 7 across the side-wall guide shaft 6, the pressing support member is connected to the side-wall guide. The flow line in the mine 6 will be cut off, and it will be difficult to carry out the excavated sediment from the side wall guide mine 6 to the rear and to carry materials such as the support 7 forward.

(2) Since the concrete side wall 12 is formed while the centre 20 is moved forward, the centle 20 is dismantled each time and the existing tunnel is constructed in order to carry out the excavated earth and sand. Retreating to the main mine 4 is very wasteful as work, prolonging the construction period and increasing the construction cost.

(3) Since it has the above-mentioned problems (1) and (2), conventionally, the side wall shaft is first formed over the entire line, and after this, the centle 20 is used. Thus, the side walls of the concrete were sequentially formed by a predetermined length, and the tunnel main pit 4 had to be excavated. Accordingly, it is difficult to shorten the construction period because the formation of the concrete side wall 12 and the excavation of the side wall guide shafts 6 and 6 cannot be performed in parallel. Moreover, it took time until the entire cross section of the tunnel main pit 4 was closed after excavating the side wall guide pits 6, 6, and the early closing could not be expected.

  This invention is made | formed in view of the said situation, The objective is that the concrete side wall formed in a side wall guide pit can be easily formed in a short time without using a steel formwork. When forming the concrete side wall, it does not obstruct the loading and unloading of equipment to and from the face blades in the side wall guide pit and the excavation of excavated earth and sand. Therefore, it is intended to provide a method of constructing a side-wall tunnel and a structure thereof that can achieve early closing of the entire cross section of the tunnel main shaft, and can greatly shorten the construction period and reduce the construction cost. .

  In order to achieve the above object, in the method for constructing a side wall tunnel according to the present invention, prior to excavation of the tunnel main shaft, a pair of side tunnels are located on the left and right sides of the tunnel main shaft. A side wall shaft formation process for excavating and forming a side wall shaft, and a concrete side wall for supporting a support work of the tunnel main shaft is formed in the pair of side wall shafts over a predetermined length. A tunnel book in which a concrete side wall is formed, and after the concrete side wall is hardened, a tunnel main pit is formed by excavating between the side wall guide pits and spanning the upper surfaces of the pair of concrete side walls to install the support. A pit forming step, and in the concrete side wall forming step, a ruler material that defines the top surface line and the inner surface line of the concrete side wall is arranged on the wall surface of the side wall guide mine, and is defined by the ruler material. In the space And construction spraying divides the cleat multiple times, and forming the concrete side walls of the desired shape by gradually filling the multilayer.

  Here, the ruler material includes a top surface lath plate that defines the top surface line, a reinforcing bar or steel material that extends in the vertical direction to define the inner surface line and supports the lath plate, and It can be set as the structure provided with the collar lath plate arrange | positioned at the collar part used as the joining surface of.

  Further, in order to achieve the above object, in the side wall tunnel structure according to the present invention, the tunnel is located at the left and right side portions of the tunnel main shaft and has a predetermined height and thickness. A pair of concrete side walls formed continuously and along the top surface portion of the pair of concrete side walls, and a support work provided along the inner peripheral surface of the tunnel main shaft, A secondary lining body provided to cover the inner peripheral surface of the support and the concrete side wall, and an invert provided on the bottom surface of the tunnel main pit, integrally formed with the secondary lining body. And the concrete side wall includes a top surface lath plate that defines a top surface portion line of the concrete side wall, and is arranged extending in a vertical direction to define an inner surface portion line of the concrete side wall and the top surface portion lath plate. Reinforcing bar or steel material And a ruler material comprising a flange lath plate disposed on the flange portion of the joining surface, and is formed by filling the inside of the ruler material with multiple layers of sprayed concrete. It is characterized by that.

  According to the construction method and the structure of the side wall tunnel of the present invention configured as described above, the center line of the concrete side wall is used instead of the centle, which is a movable steel mold. By installing a ruler material that defines the inner surface line, and spraying and filling concrete into the inner space of this ruler in multiple layers with a spraying machine, the concrete side wall is accurately shaped into a desired shape with a predetermined thickness and height. It can be formed easily and easily. In addition, since no centle is used, a concrete side wall can be formed without interrupting the flow line in the side wall guide mine. Carrying in temporary support materials provided on the surface is not hindered. For this reason, it is possible to proceed with the excavation work of the side wall guide pit, the formation of the concrete side wall, and the excavation formation work of the tunnel main mine one after another, so that the entire section of the tunnel main mine can be closed early. As a result, the construction safety can be improved as much as possible, and the construction period can be shortened and the construction cost can be greatly reduced.

  A preferred embodiment of a method for constructing a side-wall tunnel according to the present invention and a structure thereof will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic plan sectional view schematically showing a state in the middle of construction of a side-wall tunnel. Moreover, each sectional view of FIGS. 6 to 10 shown as the conventional example is common to the present embodiment, and each of the sectional views shown by the VI-VI line to the XX line in FIG. It is a sectional view. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is common in a prior art example.

  As shown in FIG. 1, in the method for constructing a side wall tunnel according to the present invention, first, as a first process, a side wall tunnel excavation process and a subsequent support installation process are sequentially performed. . That is, as in the prior art, prior to excavation of the tunnel main shaft 4 having a large cross section to be constructed, a pair of side wall guide shafts 6 and 6 are excavated on both sides of the tunnel main shaft 4, Supporting work 7 and invert 8 are temporarily installed on the peripheral surface (see FIG. 6). In the side wall excavation process, the side face guides 6 and 6 are formed by excavating and slipping the face 6a using a drilling machine or the like along a predetermined tunnel installation plan line. And the supporting work 7 which consists of sprayed concrete and H-shaped steel is installed in the inner periphery of the side wall guide pits 6 and 6 excavated in order to prevent the collapse of earth and sand. The sprayed concrete is composed of a primary spray layer and a secondary spray layer, and the H-shaped steel is sequentially built and installed along the inside of the primary spray layer. The H-shaped steel is provided at a predetermined interval in the longitudinal direction of the side wall guide shaft 6, and after the installation of the H-shaped steel, secondary spraying of concrete is further performed so as to be filled between them. That is, the strength of the sprayed concrete layer is improved by the secondary spray layer.

  When the formation of the side wall guide shafts 6 and 6 is completed, a concrete side wall forming step for forming the concrete side walls 12 in the pair of side wall guide shafts 6 and 6 is then performed. This concrete side wall forming step is performed in parallel with the side wall guide mine excavation step and its support installation step in a side wall formation region located at a predetermined length rear portion from the face 6a of the side wall guide pits 6 and 6. The concrete side wall 12 for supporting the leg part 10a of the support work 10 of the tunnel main pit 4 is formed. The concrete side wall 12 is formed along the wall surfaces which are on the outer sides of the side wall guides 6 and 6, and is formed in a predetermined length in the tunnel length direction (see FIG. 7).

  By the way, in the present invention, as shown in the enlarged vertical sectional view of FIG. 2, the concrete side wall 12 is formed by concrete spraying by a concrete sprayer 44. Here, the concrete side wall 12 forms a part of the primary lining body of the tunnel main shaft 4 together with the support work 10 and supports the leg portion 10a of the support work 10 to bear a vertical load. The wall thickness and height are required, and the top end surface that supports the leg portion 10a of the support work 10 needs to be formed flat with as little unevenness as possible. Furthermore, since it is necessary to secure the covering concrete thickness of the secondary lining body 16 to be constructed after dredging, the inner peripheral surface side of the concrete side wall 12 is adapted to the inner surface shape of the secondary lining body 16. It is necessary to form the shape with a certain degree of accuracy. However, in the conventional concrete spraying construction, it has been difficult to secure the sufficient wall thickness and outer shape accuracy.

  Therefore, in the present invention, as shown in the drawing, a ruler material 30 that defines the top surface line and the inner surface line of the concrete side wall 12 is arranged along the wall surfaces of the side wall guide shafts 6 and 6, The concrete 40 is divided into a plurality of times in a defined space and sprayed and filled in multiple layers to form the concrete side wall 12 having a desired shape.

  That is, as shown in the perspective view of FIG. 3, the ruler material 30 is disposed extending in the vertical direction to define the top surface lath plate 32 that defines the top surface portion line, and defines the inner surface portion line. A reinforcing bar 34 (or steel material) for supporting the top surface lath plate 32 and a collar lath plate 36 disposed on the collar side to be the next joining surface are provided. Here, a lath wire mesh or a punching board having an infinite number of holes formed therein can be used for the lath plates 32 and 36 of the top surface portion and the flange portion, but in this embodiment, a lath wire mesh is adopted. The top surface lath plate 32 has a width corresponding to the wall thickness at the position of the top surface portion, and is provided over a predetermined length along the side wall guide shaft 6. It is supported.

  The rebar 34 is extended along the top surface line so as to support the top surface lath plate 32 and is bent substantially horizontally, and the tip of the horizontally extending portion 34 a is the inner side of the side wall guide shaft 6. It is brought into contact with the wall and fixed. The defining portion 34b of the inner surface line that bends from the horizontal extending portion 34a and extends downward is curved in accordance with the curved shape of the secondary covering body 16, and the lower end portion is straight as a leg portion 34c. It is formed in a shape, and is placed on the upper surface of the invert 8 so as to be placed substantially vertically.

  A plurality of the reinforcing bars 34 are arranged at a predetermined pitch (preferably about 1 to 3 m). In the illustrated example, the length of the top surface lath plate 32 in the tunnel longitudinal direction is set to 2 m, and two reinforcing bars 34 are provided at a pitch of 1 m, and the top surface lath plate 32 is in the longitudinal direction. The center portion of the steel plate and one end portion on the side of the next joining surface are supported by the reinforcing bar 34. The top surface lath plate 32 has a drooping portion 32a covering the corner portion by bending the inner side end 32a of the side wall guide shaft 6 downward by a predetermined length along the inner surface portion line defining portion 34b of the reinforcing bar 34. Is formed. Further, the reinforcing bar 34 disposed at one end on the next joining surface side is attached with a flange lath plate 36 supported by the reinforcing bar 34 to define the flange.

  And the ruler material 30 formed in this way, as shown in FIG. 4, is continuously arranged on the wall of the rear side wall 12 of the rear wall that has already been formed, and is fixedly disposed on the wall surface of the side wall shaft 6. Concrete 40 is sprayed and filled into the space defined by the ruler material 30 and the flange surface of the side wall concrete 12 already formed, and the concrete side wall 12 is formed in a desired shape.

  As shown in FIG. 2 (a) or (b), the concrete 40 is sprayed and filled a plurality of times by the concrete spraying robot 44 mounted on the self-propelled vehicle 42 into the interior space of the ruler 30. The concrete layer 40a is formed in a desired shape having a predetermined thickness and height while being laminated in multiple layers step by step. Further, the ruler material 30 is buried. In addition, although it changes with differences in various conditions, from the viewpoint of strength, the maximum wall thickness required for the concrete side wall 12 is about 2.0 m. Here, FIG. 2 (a) shows a case where the sprayed concrete layer 40a is slanted and filled in multiple layers sequentially from the bottom, and FIG. 2 (b) shows the sprayed concrete layer 40a on the wall of the side wall shaft. In the case of FIG. 2 (b), it shows the case of stacking and filling in multiple layers along the vertical direction, but if the spraying thickness of one time of the concrete layer 40a is 20 cm, which has been proven in the past. The number of times of spraying is around 10 times, and the time required for the spraying and filling is approximately 120 minutes. In addition, as shown in FIG. 2A, it is preferable in terms of construction that the concrete layer 40a is formed obliquely from the bottom and sequentially laminated and filled in multiple layers. In this case, if the thickness of one spraying of the concrete layer 40a is 20 cm, if the height of the concrete side wall 12 exceeds 4 m, 20 times of spraying operations are required. If the concrete layer 40a is formed by spraying and stacking, it is difficult for dripping of the concrete and the like. Therefore, the concrete layer 40a can be formed by spraying with a single coating thickness of 20 cm or more. That is, the thickness of one application can actually be increased to about 40 cm, and therefore, it is possible to complete the application work several times. Further, since the total coating amount itself does not change, there is no significant difference in the coating time.

  That is, the concrete side wall 12 is provided with a top surface lath plate 32 that defines the top surface portion line of the concrete side wall 12 and a longitudinally extending direction so as to define an inner surface portion line of the concrete side wall 12 and the top surface portion. It has a ruler material consisting of a reinforcing bar 34 (or steel material) that supports the lath plate 32 and a heel lath plate 36 disposed on the buttock of the joint surface, and the inner space of the ruler material has a plurality of times. It has a structure in which the concrete that has been sprayed separately is filled with multiple layers.

  And if the said concrete side wall formation process is complete | finished, the tunnel main mine formation process will be performed after progress of the predetermined solidification curing time of the concrete side wall 12. FIG. In this tunnel main shaft forming step, the upper half forming step (see FIG. 8) for forming the upper half of the tunnel main shaft 4 and the lower half forming step for forming the lower half (see FIG. The process is divided into two stages.

  That is, the upper half forming step is performed in the upper half excavation area located in the rear part of the side wall forming area, and the upper ground between the side wall guides 6 and 6 is excavated and the side wall guides 6 and 6 are excavated. The support work 7 tentatively installed on the top of is removed. And it is spanned between the top end of a pair of concrete side walls 12 and 12 formed in the side wall guide pits 6 and 6, and the support work 10 is sequentially installed along the inner peripheral surface upper part of the mine. In addition, the lower half formation step is performed in the lower half excavation area located in the rear part of the upper half excavation area, and a natural mountain between the side wall tunnels 6 and 6 is excavated, and the side wall tunnel 6, 6 is removed, and the lower half of the tunnel main shaft 4 is excavated, and the main invert 14 is formed on the bottom surface of the tunnel main shaft 4. It will be formed.

  And if excavation formation of the lower half part of the tunnel main mine 4 is complete | finished, a secondary lining body formation process will be performed in the secondary lining formation area located in the back part of this lower half excavation area. In this secondary lining body forming step, the arch concrete 16 of the secondary lining body that continues to the invert 14 along the inner peripheral surface of the primary lining body composed of the concrete side walls 12, 12 and the support 10 is formed. Casting formed. Thereby, the strong cover body 18 which closes the whole cross section of the main mine is formed on the inner peripheral surface of the tunnel main mine 4, and the side wall tunnel type tunnel 2 is sequentially completed by a predetermined length (see FIG. 10). ).

  Therefore, in the side wall tunnel 2 constructed as described above, the concrete side wall 12 formed in the side wall tunnels 6 and 6 is made of concrete using the ruler 30 as described above. Since it is formed by 40 spraying constructions, it is possible to obtain a predetermined thickness while sufficiently ensuring the shape accuracy required for the concrete side wall 12 without using the centle 20, which is a conventional mobile steel formwork. It can be formed into a desired shape having a height.

  Further, since the concrete side walls 12 and 12 are formed by burying the ruler material 30 without using the center 20 of the movable steel formwork, the demolding and movement of the steel formwork is performed as in the past. , Work such as assembly is eliminated, and construction can be easily performed in a short time. Moreover, in the conventional case where the steel mold centle 20 was used, a waiting time of one day and night was required from when the concrete was placed to when it was demolded. If it forms, the construction time will be completed in several hours, and it will be immediately started by the next joint construction, Therefore A construction time can be shortened significantly.

  Furthermore, since the spraying work can be performed by the concrete spraying robot 44 mounted on the self-propelled vehicle 42 and freely movable, the concrete spraying robot 44 is installed at the rear of the tunnel main shaft in the rear after the spraying work is completed. 4 can be easily saved. For this reason, it is possible to ensure without blocking the flow line connecting the side wall guide mine excavation area on the face 6a side and the inside of the tunnel main mine 4 that has been constructed in the rear.

  Therefore, unloading of excavated earth and sand from the cutting face 6a and loading of materials such as the supporting work 7 from the tunnel main pit 4 side into the side wall guide mine excavation area is not hindered, and the side pits 6 and 6 are excavated. A series of operations such as a forming process, a concrete side wall forming process, an excavation forming process of the tunnel main pit 4 and the like can be sequentially performed in parallel. Therefore, it is not necessary to form the side wall guides 6 and 6 in advance over the entire line prior to excavation of the tunnel main shaft 4 as in the prior art, and the side wall guides 6 and 6 are excavated. However, it becomes possible to perform excavation formation work of the tunnel main pit 4 in parallel at a predetermined length rear part from the side wall mine excavation area, so that the entire cross-section of the tunnel main pit 4 can be closed as much as possible. It is possible to improve the safety of construction by going early.

  In the above-described embodiment, when the concrete side wall 12 is formed, the construction block length is set to 2.0 m, and the length of the ruler material 30 in the tunnel longitudinal direction is set to 2.0 m. However, the construction block length can be sufficiently extended to about 6.0 m, and the construction block length can be arbitrarily set in consideration of various conditions.

It is a cross-sectional view schematically showing a state in the middle of construction of the side wall tunnel type tunnel according to the present invention. It is an expanded sectional view of one side wall guide shaft in a concrete side wall formation process, (a) shows the case where a spraying concrete layer is slanted and laminated in a multilayer, (b) shows a spray concrete layer in a side wall guide shaft. It shows a case of being stacked in multiple layers along the vertical direction. It is a perspective view which shows an example of a ruler material. It is a perspective view which shows the state which installed the ruler material in the side wall guide mine. It is a plane sectional view showing roughly the state in the middle of construction of the conventional side wall tunnel. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 1 and FIG. 5 that is common to the present invention and the conventional example. FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 1 and FIG. FIG. 6 is a cross-sectional view taken along the line IIX-IIX in FIG. 1 and FIG. FIG. 6 is a cross-sectional view taken along the line IX-IX in FIG. 1 and FIG. FIG. 6 is a cross-sectional view taken along the line XX in FIG. 1 and FIG. It is an expanded sectional view of one side wall guide shaft in the conventional concrete side wall formation process.

Explanation of symbols

2 Side-wall tunnel 4 Tunnel main shaft 6 Side wall tunnel 10 Tunnel main shaft support 10a Support leg 12 Concrete side wall 14 Tunnel main shaft invert 16 Secondary lining body 30 Ruler 32 Top surface lath plate 34 Reinforcing bar 36

Claims (3)

Prior to excavation of the tunnel main shaft, a side wall shaft formation step of excavating and forming a pair of side wall guide shafts located on the left and right sides of the tunnel main shaft,
A concrete side wall forming step in which a concrete side wall for supporting a support work of the tunnel main mine is formed over a predetermined length in the pair of side wall guide shafts;
A tunnel main shaft forming step in which after the concrete side wall is hardened, a tunnel main shaft is formed by excavating between the side wall guide shafts and setting up the support works over the pair of concrete side walls. A method for constructing a side wall tunnel,
In the concrete side wall forming step, a ruler material that defines the top surface line and the inner surface line of the concrete side wall is disposed on the wall surface of the side wall guide shaft, and the concrete is placed in the space defined by the ruler material a plurality of times. Formed on the concrete wall of the desired shape by spraying and filling in multiple layers
A method for constructing a side wall tunnel.   The ruler material is a top surface lath plate that defines the top surface portion line, a reinforcing bar or steel material that extends in the vertical direction to define the inner surface portion line and supports the lath plate, and the next splicing The construction method of the side wall tunnel type tunnel according to claim 1, further comprising a collar lath plate disposed on the collar serving as a surface. A pair of concrete side walls that are located on the left and right sides of the tunnel main shaft, and have a predetermined height and thickness, and are continuously spliced along the tunnel length direction;
Spanned between the top surfaces of the pair of concrete side walls, and a support work provided along the inner peripheral surface of the tunnel main pit,
A secondary lining body provided to cover the inner peripheral surface of the support and the concrete side wall;
A side wall tunnel structure comprising an invert formed continuously with the secondary lining body and provided at the bottom of the tunnel main shaft,
The concrete side wall includes a top surface lath plate that defines the top surface line of the concrete side wall, and a reinforcing bar that extends in the vertical direction to define the inner surface line of the concrete side wall and supports the top surface lath plate. Or it has a ruler material consisting of steel and a lath lath plate arranged at the buttock of the joint surface, and the concrete is sprayed into the ruler material several times and filled in multiple layers Formed,
Sidewall tunnel structure characterized by this.

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