JP2010248758A - Hollow pipe body and tunnel construction method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow pipe body capable of efficiently forming the frozen ground. <P>SOLUTION: The hollow pipe body 1 pushed into the ground comprises freezing pipes 11 extending in the axial direction at the inside hollow side of a body comprising a steel pipe 12 and a reinforced concrete 13 and a heat insulating section 15 surrounding the inside hollow side inside the freezing pipes. The freezing pipes 11, 11 extends to positions at both sides of the hollow 10 of the body. The freezing pipes are further embedded in an additional concrete 14 integrated with the steel pipe and the reinforced concrete. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hollow tube body used when building a tunnel used for a subway, a road, or a junction branching portion thereof in an urban area or a weak ground, and a tunnel building method.

  Conventionally, when excavating the ground and forming a cavity in the ground, in order to suppress subsidence of the ground surface etc., a plurality of steel pipes are pushed ahead into the ground to construct a flat roof-like pipe roof, There is known a method of excavating the inner ground protected by the pipe roof while supporting it with a support structure such as a continuous wall with high rigidity and a support pile (see Patent Document 1).

  Patent Document 2 discloses a curved pipe roof construction method developed to construct a tunnel that linearly includes a curved portion.

  Furthermore, in Patent Documents 3 and 4, when excavating a tunnel in a weak ground, a long steel plate is cast radially in the direction of excavation to prevent the front excavation surface from collapsing. A method is disclosed.

  In Patent Document 5, a plurality of tunnels are constructed so as to have an annular shape in a sectional view by a small shield excavator, and an annular freezing zone is formed using these tunnels. Is disclosed.

Japanese Patent No. 3511145 Japanese Patent Laid-Open No. 2000-240391 JP 2004-19359 A JP-A-10-231700 JP 2007-217910 A

  However, when a flat roof-shaped pipe roof is constructed, all loads acting on the pipe roof must be supported by a support work, which can be a big problem that hinders internal excavation and increases the construction cost. It became the cause that became high. Moreover, when connecting adjacent pipe roofs with a joint etc., since the constraining force of a connection part becomes strong, it is difficult to provide a curved part.

  On the other hand, since the receiving steel materials are arranged at intervals in the transverse direction, the cross-sectional force cannot be transmitted in the transverse direction between the receiving steel materials, and the arch effect cannot be exhibited. Moreover, even if it is a case where the receiving steel materials are connected by an arch-shaped support as disclosed in Patent Document 4, the loosening of the ground progresses between the excavation and the installation of the support, and deformation occurs. Can not be suppressed.

  In addition, the method using the small shield excavator disclosed in Patent Document 5 is difficult to apply to a ground with a shallow earth covering. Furthermore, the method using the shield excavator increases the initial cost such as the machine cost, which is uneconomical when constructing a tunnel with a short distance.

  Therefore, the present invention is a hollow tube body that can efficiently form a frozen soil part, and a tunnel including a curved part in a linear manner that can suppress deformation of the ground as much as possible. The object is to provide a tunnel construction method that can be easily constructed even if it exists.

  In order to achieve the above object, a hollow tube body of the present invention is a hollow tube body that is pushed into the ground, and includes a freezing tube that extends in the axial direction on the inner side of the main body, and the freezing tube And a heat insulating layer surrounding the inner air side.

  Here, the freezing tubes can be extended to positions facing each other across the inner space of the main body. In addition, a freezing tube can be further extended between two freezing tubes that are provided to face each other with the inner space of the main body interposed therebetween.

  Furthermore, it is preferable that the freezing pipe is embedded in a concrete wall integrated with the outer peripheral surface side of the main body. Furthermore, it is preferable that the freezing tube has a projecting end toward the inner space of the main body.

  Further, the tunnel construction method of the present invention is a method of constructing a tunnel having at least the upper part formed in an arch shape in cross-section, and the hollow tube body is directed in the extending direction of the tunnel, and the tunnel is located above the tunnel. A step of pushing in so that a plurality of cryotubes respectively extending in the plurality of hollow tubular bodies are arranged side by side in the circumferential direction when pushing in a plurality of circumferentially spaced grounds on the outer circumference of the arch; A step of conveying a low-temperature antifreeze liquid to the freezing pipe to form a frozen soil portion on the outer periphery of the tunnel including between the hollow tube bodies, a step of excavating an inner peripheral side of the frozen soil portion, and a heat insulation on the excavation surface And a step of spraying a material.

  Here, when three freezing tubes are extended in the hollow tube body, two freezing tubes are arranged side by side in the circumferential direction, and the remaining freezing tube is the center of the tunnel. It is preferable to push in so that it may be arrange | positioned at the ground side on the opposite side.

  In the hollow tube body of the present invention configured as described above, a freezing tube is previously extended in the axial direction of the main body, and a heat insulating layer is formed on the inner side of the freezing tube. When this hollow tube is pushed into the ground and a low-temperature fluid such as antifreeze is passed through the freezing tube, cold heat is transmitted toward the outside without the heat insulating layer.

  Thus, since the heat radiation to the inner space side of the cold heat transmitted from the freezing pipe is suppressed by the heat insulating layer, the frozen soil portion can be efficiently formed outside the hollow tubular body. Further, if the heat insulating layer is disposed on the inner space side of the freezing tube, it is not necessary to fill the inner space of the main body with mortar, etc., so that the work at the site can be reduced and the work period can be shortened.

  In addition, if the freezing pipes are arranged at positions facing each other across the inner space of the main body, the frozen soil part can be spread on both sides of the hollow tubular body, and the belt-like frozen soil part is efficiently formed. be able to.

  Further, when three freezing tubes are extended in the hollow tube body, two freezing tubes are arranged side by side in the circumferential direction, and the remaining freezing tube is placed on the side opposite to the center of the tunnel. If it is arranged on the ground side, the ground on the outer peripheral side from the hollow tube can be efficiently frozen.

  In addition, if the freezing pipe is embedded in a concrete wall that is integrated with the outer peripheral surface side of the main body, the cold heat is transmitted through the wall and quickly reaches the outer peripheral surface side, so that it takes a short time. The frozen soil portion can be efficiently formed outside the hollow tube body.

  Furthermore, if the end of the freezing tube protrudes toward the inner space at the end of the hollow tube, it is possible to easily connect the freezing tubes to each other when a new hollow tube is added. As a result, the frozen soil formation range according to the progress of excavation can be set arbitrarily, so that the scale and cost for freezing can be minimized.

  In the tunnel construction method of the present invention, a plurality of hollow tubes are aligned and pushed into the ground on the outer periphery of the upper arch of the tunnel at intervals in the circumferential direction so that the frozen tubes are aligned. Then, antifreeze is transported by the freezing pipe in the hollow pipe body to form an arched frozen soil part on the outer periphery of the tunnel, and then the inner peripheral side of the frozen soil part is excavated, and a heat insulating material is provided on the excavated surface. Spray.

  For this reason, since the arch-like frozen soil part is formed before excavation and the arch effect can be exhibited from the beginning of excavation, the deformation can be suppressed as much as possible by minimizing the loosening of the ground due to excavation.

  Furthermore, since these hollow tube bodies are pushed in at intervals in the circumferential direction, the hollow tube bodies are not constrained and can be easily constructed even in a tunnel including a curved portion linearly. .

It is a cross-sectional view explaining the structure of the hollow tube body of embodiment of this invention. It is the fracture | rupture figure which partially fractured | ruptured the side surface in order to demonstrate the structure of the hollow tube body of embodiment of this invention. It is a longitudinal cross-sectional view explaining the structure of the joint vicinity which connected hollow tube bodies. It is a partial expanded cross-sectional view explaining the structure of the hollow tube body and the frozen soil part which were pushed in at intervals in the circumferential direction. It is a cross-sectional view explaining the process of forming a frozen soil part on the outer periphery of a tunnel. It is explanatory drawing explaining the process of excavating the inner peripheral side of a frozen soil part and spraying a heat insulating material and a waterproofing material. It is a cross-sectional view explaining the process of providing the concrete lining part in the inner peripheral side of a tunnel. It is a cross-sectional view explaining the structure of the hollow tube body of an Example. It is a partial expanded cross-sectional view explaining the structure of the hollow tube body and the frozen soil part which were pushed in at intervals in the circumferential direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating the configuration of the hollow tube body 1 of the present embodiment, and FIG. 2 is a broken view in which a part of the main body is broken to illustrate the configuration of the hollow tube body 1. FIG.

  The hollow tube 1 is a tube material that is pushed horizontally into the ground by a propulsion method or the like. The main body of the hollow tube 1 can be formed by a steel tube, a fume tube, or the like, but in this embodiment, the hollow tube 1 using a reinforced concrete centrifugal formed tube as the main body will be described.

  The hollow tube 1 includes a main body formed by a steel pipe portion 12 forming an outer peripheral surface and a reinforced concrete portion 13 formed with a substantially uniform thickness along the inner peripheral surface of the steel pipe portion 12, and the reinforced concrete portion. The freezing pipes 11 and 11 respectively extended in two places facing the inner space 10 along the inner peripheral surface 13, the additional concrete portion 14 for embedding the freezing pipes 11 and 11, and the additional concrete And a heat insulating layer 15 formed on the inner peripheral surface of the portion 14.

  On the inner peripheral surface of the cylindrical steel pipe portion 12, ribs 12a protruding toward the axial center are provided at substantially equal intervals with intervals in the circumferential direction. And the reinforced concrete part 13 of the thickness which can embed this rib 12a is formed in cyclic | annular form by centrifugal molding.

  The freezing tube 11 is a hollow steel tube that extends in parallel with the axial direction of the hollow tube 1 and carries an antifreeze such as a calcium chloride aqueous solution therein. Furthermore, since the two freezing pipes 11 and 11 are piped at positions facing each other with the inner space 10 therebetween, a structure in which cold heat is likely to diffuse toward both sides (vertical direction in FIG. 1) of the hollow tubular body 1. It has become.

  Further, the additional concrete portion 14 is formed by centrifugally molding concrete poured around the freezing pipes 11 and 11. By this additional concrete part 14, the steel pipe part 12, the reinforced concrete part 13, the frozen pipes 11 and 11, and the additional concrete part 14 are integrated.

  Further, the heat insulating layer 15 is formed on the inner peripheral surface of the additional concrete portion 14 by spraying urethane foam or the like. If the heat insulating layer 15 includes a large number of closed cells such as urethane foam, high heat insulating performance can be ensured by bubbles having low thermal conductivity.

  On the other hand, FIG. 3 is a longitudinal sectional view for explaining the configuration in the vicinity of the joint connecting the two hollow tube bodies 1A and 1B having the same configuration as the hollow tube body 1 described above. In the vicinity of the joint, the front end of a new hollow tube 1B is inserted and connected to the rear end of the hollow tube 1A that has been pushed into the ground in advance.

  At the rear end of the hollow tubular body 1A, a receiving portion 12c is formed protruding from the steel pipe portion 12 behind the rear end of the reinforced concrete portion 13. A rib 12a is embedded in the vicinity of the rear end of the reinforced concrete portion 13.

  In contrast, an insertion port 12d that is one step smaller than the diameter of the steel pipe portion 12 is formed at the front end of the hollow tubular body 1B, and a rib 12a is embedded in the reinforced concrete portion 13.

  Moreover, the ring-shaped water stop material 16 is attached to the outer peripheral surface of this insertion port 12d in two strips. Further, a ring-shaped gasket 17 is attached to the front end surface of the hollow tube 1B at a position where it abuts on the rear end surface of the hollow tube 1A.

  Further, at the end of the hollow tube 1 </ b> A (1 </ b> B), a protruding portion 11 a where the end of the freezing tube 11 protrudes toward the inner space 10 is provided. And the freezing tube 11 of the front hollow tubular body 1A and the freezing tube 11 of the rear hollow tubular body 1B are connected by connecting the projecting portions 11a and 11a by the connecting tube 111.

  The hollow tube 1 configured as described above is arranged at substantially equal intervals in the circumferential direction along the outer periphery of the upper arch of the tunnel 8 as shown in FIGS. That is, the tunnel 8 includes a plurality of hollow tubes 1,... Disposed between the hollow tubes 1 and 1 on the ground 20 on the outer periphery of the tunnel 8 in a ring shape at intervals in the circumferential direction. The frozen ground portion 2 formed in an annular shape in cross section so as to surround the outer periphery of the tunnel 8 including the heat insulating spray layer 4 formed along the inner shape of the tunnel 8 on the inner peripheral surface of the frozen soil portion 2 and waterproofing The spraying layer 5, the concrete lining portion 6 and the bottom plate 61 formed on the inner peripheral surface of the waterproof spraying layer 5, and the inner surface of the lining portion 6 are arranged to form a wall surface. It is mainly composed of the precast panel 7.

  The frozen soil portion 2 is preferably formed in an annular shape having a substantially circular cross-sectional view regardless of the shape of the inner space of the tunnel 8 so that the arch effect is easily exhibited. That is, in the present embodiment, as shown in FIG. 7, the inner shape of the tunnel 8 is formed in a horseshoe shape in cross section, and the ground 20 is between the bottom plate 61 and the arc-shaped frozen soil portion 2 below. Is left.

  Moreover, in order to form the frozen soil part 2 in which the arch effect is easily exhibited, the hollow tube body 1 has a frozen pipe 11,... On the outer circle S assumed on the outer periphery of the tunnel 8 as shown in FIG.・ Position it so that it is lined up and push it into the ground 20.

  When the hollow tubes 1,... Are arranged in such a direction, the distance between the freezing tubes 11, 11 of the adjacent hollow tubes 1, 1 is the shortest, and the antifreezing liquid is placed in the freezing tubes 11, 11. When circulates, the frozen soil part 2 is formed between the hollow tube bodies 1 and 1 in a short time, and the arch effect is exhibited.

  Further, as a means for confirming the generation state of the frozen soil portion 2, a temperature measuring tube 21 is pushed into the ground 20 in parallel with the hollow tube 1, and a temperature measuring tube 22 is disposed inside the hollow tube 1. The As shown in FIG. 4, the temperature measuring tube 22 is disposed between the freezing tubes 11 and 11 at a position on the outer peripheral side of the heat insulating layer 15 similarly to the freezing tubes 11 and 11.

  The heat insulating spray layer 4 provided along the inner peripheral surface of the frozen soil portion 2 formed in this manner is formed by spraying a heat insulating material such as a foamed instantaneous setting slurry onto the excavation surface.

  For the instant foaming slurry, urethane-based foamed urethane, cement-based foamed mortar, foamed mortar mixed with EPS (foamed polystyrene) particles or vinylon, or the like can be used. Since the heat insulating spray layer 4 formed of such a foaming and setting slurry has a large number of closed cells having low thermal conductivity, high heat insulating performance can be ensured.

  And this heat insulation spraying layer 4 is cast in the inner peripheral side by the thickness of the extent that the frozen soil part 2 is not melted by the hardening heat of the concrete casted on the inner peripheral side, or the cold heat of the frozen soil part 2 The resulting concrete is sprayed to a thickness that does not cause poor curing.

  The waterproof spray layer 5 is formed by spraying a urethane or asphalt waterproof material on the inner peripheral surface of the heat insulating spray layer 4. Thus, if it is the method by spraying, even if the surface of the heat insulation spraying layer 4 has an unevenness | corrugation, a waterproof structure can be formed easily.

  Then, the heat insulating spray layer 4 and the waterproof spray layer 5 are formed so as to surround the inner shape of the tunnel 8 as shown in FIG.

  Further, on the inner peripheral surface side of the waterproof spray layer 5 located at the bottom of the tunnel 8, a bottom board 61 is constructed of reinforced concrete. In addition, the lining portion 6 having a semicircular cross-sectional view is constructed from reinforced concrete from both side edges of the bottom plate 61.

  Further, a precast panel 7 formed in an arc plate shape at a factory or the like is disposed on the inner peripheral surface side of the lining portion 6. Here, when making this precast panel 7 function as a formwork, after installing the precast panel 7, the outer peripheral side is filled with concrete and the lining part 6 is constructed.

  Next, a method for constructing the tunnel 8 according to the present embodiment will be described.

  First, the hollow tube body 1 in which the freezing tubes 11 and 11 are extended is manufactured in a factory or a work yard. The hollow tube 1 has a diameter of about 1000 mm, for example, and the freezing tube 11 piped therein has a diameter of about 100 mm.

  On the other hand, at the site where the tunnel 8 is constructed, a start shaft (not shown) is provided on the ground 20 adjacent to the tunnel 8. Then, as shown in FIG. 4, the orientation of the hollow tube body 1 is adjusted so that the frozen tubes 11 and 11 are arranged on the outer circular line S from the inside of the start shaft.

  Here, for example, a muddy water type propulsion device (not shown) is disposed at the tip of the hollow tube body 1, and the ground 20 is cut by the propulsion device and the rear end of the hollow tube body 1 is started. Thrust is given by pushing with a propulsion jack (not shown) installed in the shaft, and the hollow tube 1 is pushed into the ground 20.

  Further, since this hollow tube 1 is formed so that one length is shorter than the width of the inner space of the start shaft, for example, as shown in FIG. 3, the preceding hollow tube 1A When the tube is pushed down to a predetermined length, a new hollow tube 1B is added, and the addition is repeated until the desired length is reached.

  Further, as shown in FIG. 4, at another position on the outer circular line S, the hollow tubes 1,... Are sequentially pushed in at a distance from the pushed hollow tube 1 in the circumferential direction. Follow the same procedure.

  Moreover, as shown in FIGS. 4 and 5, a temperature measuring tube 21 is pushed into the ground 20 at a position separated from the hollow tube 1 on the outer peripheral side so that the temperature of the ground 20 can be measured. Further, some of the hollow tubes 1 pushed into the ground 20 are provided with temperature measuring tubes 22 extending therein so that the temperature of the hollow tubes 1 can be measured.

  Then, as shown in FIG. 5, a frozen soil portion 2 having an annular cross-sectional view is formed so as to surround the outer periphery of the tunnel 8.

  The construction of the frozen soil portion 2 is performed by circulating an aqueous calcium chloride solution as an antifreeze solution from the starting shaft to the freezing pipes 11. That is, in the inner space 10 of the hollow tube 1 arranged at the foremost end, the protrusions 11a and 11a of the freezing tubes 11 and 11 are connected on the tip side, and the antifreeze liquid fed from the start shaft is After being transported to the tip by the freezing pipe 11, it flows into the other freezing pipe 11 and is returned to the start shaft. Then, the antifreeze liquid whose temperature has risen due to heat exchange with the ground 20 and has returned to the start shaft is cooled by a refrigerator (not shown) and sent out to the freezing pipe 11 again.

  When the low-temperature antifreeze is circulated in the hollow tube 1 by the freezing tubes 11 and 11 in this way, the cold heat moves to the ground 20 on the outer peripheral side of the main body without the heat insulating layer 15, and the frozen 20 Is formed. The generation state of the frozen soil part 2 can be estimated by the temperature measured by the temperature measuring tubes 21 and 22.

  When the annular frozen ground portion 2 as shown in FIG. 5 is completed, the ground 20 on the inner peripheral side is protected by the arch effect of the frozen soil portion 2. Therefore, the excavator 3 such as a backhoe carried into the start shaft is used to excavate the inner peripheral side of the frozen soil portion 2 as shown in FIG.

  Since this excavation is excavation on the inner circumference side protected by the frozen soil portion 2, it is not necessary to divide into small sections and perform it step by step, and the entire section of the tunnel 8 can be excavated at a time. Is good.

  Then, a surface of the frozen soil exposed by excavation can be protected by spraying a heat insulating material such as an instant foaming slurry on the excavation surface to form the heat insulating spray layer 4.

  Further, if the heat insulating material is blown in conjunction with excavation in this way, even if the temperature in the tunnel 8 rises due to construction or inflow of air, the heat is not transmitted to the frozen soil part 2 to prevent melting. it can.

  Further, a waterproof spray layer 5 is formed on the inner peripheral surface side of the heat insulating spray layer 4 by spraying a waterproof material such as urethane material.

  And the reinforcement for the lining part 6 is performed on the inner peripheral surface side of the waterproof spray layer 5, and the precast panel 7 is attached to the inner peripheral side as shown in FIG. Further, between the legs of the precast panel 7, concrete is placed in a flat plate shape to construct the bottom board 61.

  On the other hand, concrete is also placed on the outer peripheral side of the precast panel 7. The concrete flows into the gap between the precast panel 7 and the waterproof spray layer 5 and is filled from the bottom toward the top, whereby the lining portion 6 is constructed.

  The excavation work on the inner peripheral side of the tunnel 8 described above, the spraying work of the heat insulating spray layer 4 and the waterproof spray layer 5, the mounting work of the precast panel 7 and the concrete placing work are performed at once over the entire length of the tunnel 8. Rather than being done, the work is repeated in unit length.

  On the other hand, the hollow tubes 1,... Can be pushed in at once over the entire length of the tunnel 8. Further, a series of operations from excavation on the inner peripheral side of the tunnel 8 can be performed only for a predetermined distance, and only a section corresponding to this can be frozen in advance, and this section can be moved sequentially. As a result, the frozen ground formation range according to the progress of excavation and construction can be set arbitrarily, so that the scale and cost for freezing can be minimized.

  Next, the effect | action of the construction method of the hollow tube 1 of this Embodiment and the tunnel 8 using the same is demonstrated.

  In the hollow tube body 1 of the present embodiment configured as described above, the freezing tubes 11 and 11 are previously extended in the axial direction of the main body, and the heat insulating material surrounding the inner air side from the freezing tubes 11 and 11. Layer 15 is formed.

  When the hollow tube 1 is pushed into the ground 20 and a low-temperature fluid such as antifreeze is passed through the freezing tubes 11, 11, the cold of the antifreeze is transferred to the outer peripheral surface of the hollow tube 1 without the heat insulating layer 15. Will be transmitted toward.

  As described above, since the heat radiation of the cold heat transmitted from the freezing tubes 11 and 11 to the inner space 10 is suppressed by the heat insulating layer 15, even if the inner space 10 is not filled with mortar or the like, The frozen soil portion 2 can be formed by efficiently transmitting cold heat to the ground 20, and the work on site can be reduced, so that the work period can be shortened.

  That is, in the conventional freezing method, the hollow tube is pushed into the ground 20 and then the frozen tube is inserted, so that not only the piping work of the frozen tube on site is required, but also the ground 20 is efficiently cooled. However, the work of filling the inside of the tube with mortar or the like is necessary, but by using the hollow tube 1 of the present embodiment, these operations can be omitted.

  Moreover, if the freezing pipes 11 and 11 are respectively disposed at positions facing each other with the inner space 10 interposed therebetween, the frozen ground part 2 can be spread on both sides of the hollow tubular body 1, and the belt-like frozen ground part 2 can be formed. It can be formed efficiently.

  Furthermore, if the freezing pipes 11 and 11 are embedded in the additional concrete part 14 integrated with the steel pipe part 12 on the outer peripheral surface side, the cold heat of the freezing pipe 11 is added to the additional concrete part 14, the reinforced concrete part 13 and the steel pipe. Since the parts are quickly transmitted in the order of the parts 12, the frozen soil part 2 can be efficiently formed outside the hollow tube 1 in a short time.

  Moreover, since the additional concrete part 14, the reinforced concrete part 13, and the steel pipe part 12 are integrated in an annular shape, cold heat spreads around the entire circumference of the hollow tubular body 1 and efficiently surrounds the hollow tubular body 1. The frozen soil part 2 can be formed.

  Further, if the end portion of the hollow tube body 1 is provided with a protruding portion 11a in which the end portion of the freezing tube 11 protrudes toward the inner space 10, the hollow tube body 1 is newly added. The freezing tubes 11 and 11 can be easily connected from the inner space 10.

  The presence of the projecting portion 11a allows the freezer (not shown) and the freezing pipe 11 to be connected by the projecting portion 11a at an arbitrary position, and limits the frozen soil formation range according to the progress of excavation and construction. Since it can be set arbitrarily, such as to do so, the scale and cost for freezing can be minimized.

  Further, in the construction method of the tunnel 8 of the present embodiment configured as described above, a plurality of hollow tubular bodies 1,... Are provided on the ground 20 on the outer periphery of the upper arch of the tunnel 8 at intervals in the circumferential direction.・ Push in. Then, the antifreezing liquid is conveyed to the freezing pipes 11, 11 in the hollow tube body 1, and the annular (arch-shaped) frozen soil portion 2 is formed on the outer periphery of the tunnel 8, and then the inner peripheral side of the frozen soil portion 2. The heat insulating spray layer 4 is formed on the excavation surface by spraying.

  For this reason, the annular frozen soil part 2 closed before excavation is formed, and since the arch effect can be exhibited from the beginning of excavation, the deformation of the ground 20 is minimized and the deformation is suppressed as much as possible. be able to.

  In particular, since the frozen soil portion 2 is formed, the tunnel 8 can be safely constructed even under pressured water such as directly under a river or in a gravel layer mixed with cobblestone.

  Moreover, since the upper ground is received in advance by these hollow tube bodies 1, ... by pushing the hollow tube bodies 1, ... into the outer periphery of the upper arch, it is possible to reliably suppress peeling and dropping. be able to.

  That is, the construction method of the tunnel 8 according to the present embodiment incorporates a pipe roof construction method for pushing the hollow tubes 1,... Into the ground 20, so that the tunnel 8 can be safely used even in the ground 20 with a shallow earth covering. Can be built. Moreover, if it is the construction method which pushes in the hollow tube 1, since an expensive shield excavator is not used, it is economical.

  Further, since these hollow tube bodies 1,... Are pushed at intervals in the circumferential direction, the hollow tube bodies 1, 1 are not constrained, and the tunnel 8 has a linear S shape or clothoid curve. Even so, it can be easily constructed.

  Moreover, by melting the excavated surface by forming a heat insulating spray layer 4 by spraying a heat insulating material on the excavated surface, it is possible to prevent the frozen soil portion 2 from melting. In particular, when the concrete lining portion 6 is provided on the inner peripheral surface side of the tunnel 8, the arch effect may be reduced if the frozen soil portion 2 is melted by the heat of hardening of the concrete, but the heat insulating spray layer 4 is interposed. Melting can be prevented.

  Furthermore, when the low temperature of the frozen soil part 2 is transmitted to the lining part 6 before hardening, there is a risk that the concrete may be hardened, but the high-quality concrete can be obtained by interposing the insulating spray layer 4 to block the cold heat. Can be.

  In addition, if the method of attaching the precast panel 7 and filling it with the mold as a formwork is not necessary to remove the mold, the lining part 6 of the tunnel 8 can be constructed quickly and easily. it can.

  Furthermore, a high-quality lining (tunnel inner wall) can be formed by using the precast panel 7 manufactured in a factory where quality is controlled. Moreover, if it is the precast panel 7, adjustment of a material, such as making it high intensity | strength, can also be performed easily.

  Next, a hollow tube 91 having a form different from that of the above embodiment will be described with reference to FIGS. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  The hollow tube 91 described in this example has a configuration in which a freezing tube 911 is added to the hollow tube 1 described in the above embodiment.

  As shown in FIG. 8, the freezing tube 911 is extended between freezing tubes 11 and 11 that are respectively extended at two locations facing each other across the inner space 10. That is, the freezing pipe 911 is a position adjacent to the inner peripheral surface of the reinforced concrete portion 13, and at an intermediate point of an arc extending from one freezing pipe 11 along the inner peripheral surface of the reinforced concrete portion 13 to the other freezing pipe 11. It is plumbed.

  The freezing pipe 911 is embedded in the additional concrete portion 14 and is adjacent to the inner space 10 through the heat insulating layer 15, similarly to the other freezing pipes 11 and 11.

  Furthermore, as shown in FIG. 9, the hollow tube body 91 manufactured in this manner is configured such that a freezing tube 911 is piped on the ground side opposite to the center of the tunnel 8 (outside the outer circular line S). Is pushed into.

  On the other hand, when three freezing tubes 11, 11, 911 are piped to the hollow tube 91, for example, the antifreeze is sent to the tip of the hollow tube 91 by the freezing tube 911, and the antifreeze is passed through the remaining freezing tubes 11, 11. Can be circulated. In addition, the structure which circulates by connecting the return pipe which is not illustrated in the inner space 10, and connecting with the freezing pipe 911 may be sufficient.

  By using the hollow tube body 91 configured in this way, the frozen soil portion 2 is thicker on the ground 20 on the outer peripheral side of the tunnel 8 than on the ground 20 on the center side of the tunnel 8 where excavation is performed in the process after freezing. Since it can be formed, it is efficient.

  Moreover, by adding the freezing tube 911, the time taken for the ground 20 to freeze can be shortened. Furthermore, the thickness of the frozen soil portion 2 can be easily adjusted, and the freezing efficiency can be improved.

  Other configurations and operational effects are substantially the same as those in the above-described embodiment, and thus the description thereof is omitted.

  The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to the embodiment and the example, and the design change is within a range not departing from the gist of the present invention. Are included in the present invention.

  For example, in the above-described embodiment, the case where the tunnel 8 having a horseshoe-shaped cross section is constructed is described. However, the present invention is not limited to this, and a tunnel having a circular cross section or an elliptical cross section may be used. Good.

  Moreover, in the said embodiment, although the cyclic | annular frozen soil part 2 near circular was formed, it is not limited to this, For example, if the upper part is the shape closed by the arch shape, for example, the horseshoe-shaped tunnel 8 of It may be a frozen soil part having a shape close to the interior shape. Furthermore, depending on the geology of the ground 20 and the allowable subsidence amount, the frozen soil portion 2 is formed by arranging the hollow tubes 1,... Only in the vicinity of the top of the upper arch or in a semicircular shape from the top to the leg. It may be configured to.

  Moreover, in the said embodiment, although the method of placing concrete inside the waterproof spraying layer 5 and constructing the lining part 6 was demonstrated, it is not limited to this, Before placing concrete If the method is to install a steel internal support, the deformation of the ground 20 can be suppressed even if the thickness of the frozen soil portion 2 is reduced, so that the freezing range can be reduced.

1, 1A, 1B Hollow tube body 10 Inner space 11 Freezing tube 11a Protruding portion 12 Steel tube portion (main body)
13 Reinforced concrete part (main body)
14 Additional concrete section (concrete wall)
15 Thermal insulation layer 2 Frozen soil part 20 Ground 4 Thermal insulation spray layer (thermal insulation)
5 Waterproof spray layer (waterproof material)
6 lining (concrete)
8 Tunnel 91 Hollow tube body 911 Freezing tube

Claims (7)

A hollow tube pushed into the ground,
A freezing pipe extending in the axial direction on the inner air side of the main body,
A hollow tube body comprising a heat insulating layer surrounding an inner space side of the freezing tube.   The hollow tube body according to claim 1, wherein the freezing tubes are respectively extended at positions facing each other across the inner space of the main body.   The hollow tube body according to claim 2, wherein a freezing tube is further extended between two freezing tubes that are extended to face each other with the inner space of the main body interposed therebetween.   The hollow tube body according to any one of claims 1 to 3, wherein the freezing tube is embedded in a concrete wall integrated with the outer peripheral surface side of the main body.   The hollow tube body according to any one of claims 1 to 4, wherein an end portion of the freezing tube projects toward an inner space of the main body. A method of constructing a tunnel having at least an upper part formed in an arch shape in cross section,
When the hollow tube body according to any one of claims 1 to 5 is pushed in toward the extending direction of the tunnel, and a plurality of the hollow tube bodies are circumferentially spaced from the ground of the outer periphery of the upper arch of the tunnel. A step of pushing so that the frozen tubes respectively extending in the plurality of hollow tube bodies are arranged side by side in the circumferential direction;
Forming a frozen soil portion on the outer periphery of the tunnel including between the hollow tubes by transporting a low-temperature antifreeze to the freezing pipe;
Excavating the inner peripheral side of the frozen soil part;
And a step of spraying a heat insulating material on the excavation surface. A method of constructing a tunnel having at least an upper part formed in an arch shape in cross section,
When the hollow tube body according to claim 3 is pushed in toward the extending direction of the tunnel and spaced apart in the circumferential direction on the ground on the outer periphery of the upper arch of the tunnel, the plurality of hollow tubes Two of the freezing pipes extending in the body are arranged side by side in the circumferential direction, and the remaining one freezing pipe is pushed in so as to be arranged on the ground side opposite to the center of the tunnel. Process,
Forming a frozen soil portion on the outer periphery of the tunnel including between the hollow tubes by transporting a low-temperature antifreeze to the freezing pipe;
Excavating the inner peripheral side of the frozen soil part;
And a step of spraying a heat insulating material on the excavation surface.

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