JP2006342518A - Insulation coating structure of frozen ground surface, and insulation coating method for frozen ground surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation coating structure of a frozen ground surface and an insulation coating method for the frozen ground surface capable of preventing a construction period from being increased and securely reducing the change of the cross sectional shape of a hollow formed in the ground at low cost by maintaining the self-supporting property of the surface of a frozen ground without using a steel support or a support structure formed of a shotcrete. <P>SOLUTION: An insulator 15 is stuck on the surface 13 of the frozen ground formed around the hollow in the ground through a freezing material 14 frozen to the surface 13 of the frozen ground by a self-retaining water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat insulating coating structure on a frozen ground surface applied to the surface of a frozen ground and a heat insulating coating method on the frozen ground surface.

  In recent years, a tunnel construction method (SR-J construction method) has been proposed in which a branching junction between a main shield tunnel and a lamp shield tunnel constructed by a shield construction method in a road tunnel is constructed. In this SR-J method, first, the lamp shield tunnel is advanced ahead of the main line shield tunnel, and is stopped until the lamp shield tunnel reaches at least the planned construction position of the branch junction, and the roof shield starts from the vicinity of the tip. Shield roof that surrounds the branch junction by constructing a number of roof shield tunnels along the extension direction of the branch junction by placing the machine in a state of being closely arranged along the outline of the branch junction Build a pre-construction. Then, the surrounding ground is frozen from the inside of the roof shield tunnel to form a freezing zone between the roof shield tunnels. In parallel with the construction of the roof shield tunnel, the main shield tunnel is dug to pass through the inside of the shield roof tip receiver. Thereafter, freeze tubes are inserted into the inner ground from both ends of the roof shield tunnel, and the ground inside both ends of the shield roof tip receiver is frozen to form a freezing zone. After that, the main shield tunnel is widened inside the shield roof tip receiving and freezing zone, the tip of the lamp shield tunnel is joined to the widened portion, and the lining wall of the branching junction is constructed.

  In the tunnel construction by the SR-J method described above, the surface of the ground in the freezing zone is consolidated by freezing and becomes more independent, but in order to maintain the independence of the frozen ground surface for a long period of time. In addition, a support structure is formed. This support structure is composed of a steel support and shotcrete, as in the case of a normal NATM (New Austrian Tunneling Method) method, and the shotcrete is directly sprayed on the surface of the widened ground.

In recent years, a method of installing a heat insulating material on the ground surface has been proposed in order to improve the freezing effect when freezing the ground. This method is to excavate a tunnel underground, let the frozen pipe penetrate into the surrounding ground from the inside of this tunnel, and after installing a heat insulating material having flexibility at a very low temperature such as polyurethane foam on the ground surface, In this method, water is injected into the tunnel for filling, and then the ground is frozen by circulating low temperature gas (refrigerant) through the freezing pipe to the ground around the tunnel (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 4-120317

However, in the method of maintaining the independence of the ground surface by the support structure described above, the ground inside the both ends of the shield roof tip receiver is frozen and becomes frozen soil of about -15 ° C. The sprayed concrete sprayed directly onto the surface may not solidify and may not be able to exert its support effect. Further, since the excavated tunnel is supported by a support structure composed of a support work and shotcrete for about three years from the start of excavation, there are problems such as deterioration of the shotcrete and occurrence of cracks. In addition, when cracks occur in shotcrete, the temperature of the frozen ground locally increases, and the amount of settlement on the top face of the excavation tunnel increases due to a decrease in strength and deformation coefficient, which may cause the frozen ground to collapse. In other words, according to the support structure described above, the ground may not be properly supported due to poor solidification or deterioration of the shotcrete, and cracks, and there is a problem that the reliability of the effect of reducing the displacement of the inner peripheral surface of the tunnel is low. Exists.
In addition, the excavation work is divided into a plurality of sections, and support work is built and spray concrete is sprayed at each construction stage, so there is a problem that the construction period becomes long.
Furthermore, in order to prevent melting of the frozen ground surface during the construction period and maintain the independence of the ground, it is necessary to continuously perform the freezing operation using the above-mentioned freezing pipe, and there is a problem that costs increase. .

  In addition, the conventional ground surface freezing method described above is a method of freezing the ground after installing a heat insulating material on the ground surface, and a tunnel was excavated to maintain the independence of the ground surface before freezing. Later, since a support structure made of steel support or shotcrete is required, excavation work is carried out by dividing it into multiple sections. There is a problem that the work period becomes longer and the construction period becomes longer.

  The present invention takes the above-described conventional problems into consideration, and maintains the self-supporting property of the surface of the frozen ground for a long period without using a support structure made of steel support or shotcrete. It is possible to provide a heat insulation coating structure on a frozen ground surface and a method for heat insulation coating on a frozen ground surface that can reduce the deformation of the cross-sectional shape of the cavity formed in the ground at low cost and with certainty. Objective.

  The invention related to the heat insulating coating structure on the frozen ground surface according to claim 1 is provided on the surface of the frozen ground formed around the underground cavity via a freezing material that freezes on the frozen ground surface by its own water retention, It is characterized by affixing a heat insulating material.

  In the invention relating to the heat insulating coating method for the frozen ground surface according to claim 2, the surface of the frozen ground formed around the underground cavity is water-retained by a freezing material having water retention and is frozen to the frozen ground surface. Thus, the heat insulating material is pasted through the freezing material.

  Due to the above-described characteristics, the water of the freezing material immediately freezes on the frozen ground at a low temperature, so that the freezing material exhibits the adhesion performance to the surface of the frozen ground. The heat insulating material is appropriately attached to the surface of the frozen ground by this freezing material. In addition, the heat insulating material adhered to the surface of the frozen ground prevents melting of the frozen ground surface and maintains the frozen state.

  The invention described in claim 3 is characterized in that, in the heat insulating coating method for a frozen ground surface according to claim 1, a freeze-fitting material is previously attached to the heat insulating material.

  With such a feature, a heat insulating coating layer is formed on the frozen ground surface only by pressing the heat insulating material provided with the freezing material against the frozen ground surface.

According to the heat insulation coating structure of the frozen ground surface and the heat insulation coating method of the frozen ground surface according to the present invention,
A heat insulating material is properly attached to the surface of the frozen ground by a freezing material that exhibits adhesion performance to the surface of the frozen ground, and this heat insulating material prevents the frozen ground surface from melting and maintains the frozen state. Therefore, the free standing of the surface of the frozen ground can be maintained for a long time. As a result, a support structure made of steel support work or shotcrete can be omitted, deformation of the cross-sectional shape of the cavity formed in the ground can be reliably reduced, and cost can be further reduced. At the same time, the construction period can be shortened.

  In addition, by pre-installing a heat insulating material on the surface of the freezing material, the work inside the cavity is simplified compared to the case where the freezing material and the heat insulating material are installed separately, thereby shortening the construction period. Can be achieved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a heat insulating covering structure on a frozen ground surface and a heat insulating covering method on a frozen ground surface according to the present invention will be described below with reference to the drawings. In the present embodiment, a case where a branching junction between the main shield tunnel 1 and the lamp shield tunnel 2 constructed by a shield method in a road tunnel is constructed will be described as an example.

  First, the process of forming the frozen ground around the cavity formed in the ground will be described. 1 is a perspective view showing an outline of a tunneling method for constructing a branch / merging portion, FIG. 2 is a plan view showing the entire branch / merging portion, and FIG. 3 (a) is a method for forming a frozen ground. 2 is a cross-sectional view taken along the line A-A shown in FIG. 2, and FIG. 3B is a cross-sectional view taken along the line BB shown in FIG. 2 showing a method for forming a frozen ground.

  As shown in FIG. 1, first, the lamp shield tunnel 2 is advanced ahead of the main shield tunnel 1, and as shown in FIG. 2, the lamp shield tunnel 2 is excavated until it reaches at least the planned construction position of the branch junction. Stop. Then, the roof shield machine 5 shown in FIG. 1 is started from the side wall near the front end of the lamp shield tunnel 2, and a plurality of (20 in the illustrated example) along the extension direction of the branch / merging portion are arranged outside the planned construction position of the branch / merging portion. Excavate the roof shield tunnel 6). These roof shield tunnels 6 are constructed in a state of being arranged at a predetermined interval along the contour of the branch and merge part, and the shield roof tip receiving work 3 is constituted by the whole of the plurality of roof shield tunnels 6.

On the other hand, the main shield tunnel 1 is dug in parallel with the construction of the shield roof tip receiver 3 as described above, and the main shield tunnel 1 is passed through the inside of the shield roof tip receiver 3.
3 (a) and 3 (b), a plurality of freezing pipes 7 are installed in the roof shield tunnel 6 ..., respectively, and the roof shielding tunnel 6 ... The frozen ground 8 is formed between the roof shield tunnels 6 and 6, respectively.
In addition, after the main line shield tunnel 1 passes through the inside of the shield roof tip receiving work 3, as shown in FIGS. 3 (a) and 3 (b), a plurality of roof shield tunnels 6 are connected to the inner ground from both ends thereof. The freezing pipe 9 is inserted into each boring hole, and the ground in the freezing range 10 located at both ends of the shield roof tip receiver 3 shown in FIG. 2 is frozen to form the frozen ground 11. .
Through the above steps, the planned construction position of the branching / merging portion is surrounded by the shield roof tip receiving work 3 and the frozen grounds 8 and 11, and is isolated from the outer ground.

  Next, a step of widening the main shield tunnel 1 surrounded by the shield roof tip receiving work 3 and the frozen grounds 8 and 11 is performed. 4A is a cross-sectional view taken along the line AA in FIG. 2 showing a state where the main shield tunnel 1 is widened, and FIG. 4B is a diagram showing a state where the main shield tunnel 1 is widened. It is sectional drawing between BB shown in FIG.

  As shown in FIGS. 4 (a) and 4 (b), for example, a part of the wide side wall of the main shield tunnel 1 is removed inside the shield roof tip receiver 3, and excavating machines such as a backhoe are removed therefrom. And the excavating machine excavates the widened portion of the branch and merge portion from above to below and removes the unnecessary portion of the side wall of the main shield tunnel 1 to widen the main shield tunnel 1 and A cavity 12 is formed. The wall surface of the cavity 12 is wholly or partially frozen, and the wall surface (the frozen ground surface 13) of the cavity 12 composed of the frozen grounds 8 and 11 is in a self-supporting state.

  Next, the heat insulation coating structure applied to the above frozen ground surface 13 will be described. FIG. 5 is an enlarged cross-sectional view showing the heat insulation coating structure.

  As shown in FIG. 5, the heat insulating covering structure applied to the frozen ground surface 13 has a configuration in which a heat insulating material 15 is attached to the frozen ground surface 13 via a freezing material 14. The freezing material 14 and the heat insulating material 15 are planar members respectively installed along the inner peripheral surface of the cavity 12, and the freezing material 14 is attached to the frozen ground surface 13. The heat insulating material 15 is laminated on the inner side surface (surface).

When the freezing material 14 is brought into contact with the frozen ground surface 13, the frozen water is frozen on the frozen ground surface 13 by freezing the water retained by itself. The material is not particularly particular as long as it has self-water retention, such as synthetic resin, synthetic fiber, natural material, etc. The shape is woven, non-woven, sponge, and relatively thin sheet Preferably used. In attaching the freezing material 14 to the heat insulating material 15, the heat insulating material 15 may be applied to the entire surface or a part of the heat insulating material 15. Good.
As the heat insulating material 15, a flexible planar member is used in addition to heat insulating properties. For example, glass wool, rock wool, foamed polyurethane, foamed polystyrene, or the like can be used. In view of the possibility that the ground will loosen when the heat insulating material 15 is crushed when the lining 4 described later is applied and the frozen ground 8 and 11 are released from the frozen state, A heat-insulating synthetic resin foam such as foamed polyurethane and foamed polystyrene that is hard and hardly crushed is used. In addition, when using a heat insulating synthetic resin foam such as foamed polyurethane and foamed polystyrene as the heat insulating material 15, those having a thickness of about 3 to 4 cm are used, and when using glass wool or rock wool, Those having a thickness of about 10 cm are used.

  Next, the heat insulation coating method which constructs the heat insulation coating structure which consists of an above-described structure on the frozen ground surface 13 is demonstrated.

  First, a heat insulating panel 16 (covering material) in which a sheet material 17 (in this embodiment, a sheet-like non-woven fabric) constituting the freezing material 14 is previously attached to the surface of the heat insulating material 15 is formed. Specifically, the sheet material 17 is cut into about 2 m square, the sheet material 17 is spread, and a heat insulating synthetic resin foam (heat insulating material 15) such as polyurethane foam and polystyrene foam is formed on the sheet material 17 to the predetermined thickness. The heat insulation panel 16 is shape | molded by spraying. In addition, this process may be performed on-site and the heat insulation panel 16 may be shape | molded on-site, or the said process may be performed in a factory and the molded heat insulation panel 16 may be carried in to the field. Moreover, you may make it stick the sheet | seat material 17 to the heat insulating material 15 by adhesion | attachment or welding by using the heat insulating material 15 as a molded article.

Next, the surface on the sheet material 17 side of the heat insulating panel 16 described above is wetted with water so that the sheet material 17 sufficiently contains water, and the surface on the sheet material 17 side is then frozen ground surface 13 side. Then, the heat insulating panel 16 is pressed against the frozen ground surface 13 in a state where it is adhered to the frozen ground surface 13.
By the above-described method, the heat insulation panel 16 is adhered to the frozen ground surface 13 without a gap, so that the heat insulating coating structure is installed on the frozen ground surface 13.

  After the above-described heat insulation coating structure is installed, as shown in FIG. 4, a covering 4 having a cross-sectional shape that is horizontally long and elliptical is applied along the inner peripheral surface of the cavity 12 by a well-known method.

  According to the heat insulating covering structure of the frozen ground surface 13 and the heat insulating covering method of the frozen ground surface 13 having the above-described configuration, the water of the sheet material 17 is immediately frozen by the low temperature frozen ground, so that the freezing material 14 becomes the frozen ground surface. Adhesion performance is demonstrated with respect to 13. The heat insulating material 15 is appropriately attached to the frozen ground surface 13 by the freezing material 14 exhibiting the adhesion performance to the frozen ground surface 13, and the heat insulating material 15 prevents the frozen ground surface 13 from being melted and frozen. Is maintained. For this reason, the self-supporting property of the frozen ground surface 13 can be maintained over a long period of time, and the temperature on the excavation surface side does not decrease when, for example, a concrete lining 4 is placed, so the quality of the lining 4 Can be improved.

  Further, when the deformation of the cross-sectional shape of the cavity 12 is analyzed, when the support structure is omitted by installing only the above-described heat insulation coating structure, the increase in the amount of settlement of the top end surface of the cavity 12 is the case where the conventional support structure is installed. In comparison, a result of about 10% was obtained, and when the above-described heat insulating coating structure is installed, a support structure made of steel support or sprayed concrete can be omitted. Accordingly, there is no need to support the inside of the cavity 12 with shotcrete that may cause poor solidification, deterioration, or cracks, and deformation of the cross-sectional shape of the cavity 12 formed in the ground can be reliably reduced. Further, since the frozen ground surface 13 is covered with the heat insulating material 15, the continuous freezing operation for preventing the frozen ground surface 13 from being melted is unnecessary, and the cost can be reduced. Furthermore, since the assembly work of the support structure made of steel support work or shotcrete is eliminated, the construction cycle is significantly shortened, and the work period can be shortened to about 1/2 to 1/3.

  In addition, since the heat insulation panel 16 is lightweight, even if the entire surface of the freezing material 14 is not in close contact with the frozen ground surface 13, it does not fall off from the frozen ground surface 13, for example, even on the ceiling surface. Never fall.

  Further, a heat insulating material 15 is attached to the surface of the sheet material 17 in advance, and the surface on the sheet material 17 side of the heat insulating material 15 provided with the sheet material 17 is wetted, and then the surface on the sheet material 17 side is frozen. Since the heat insulating material 15 provided with the sheet material 17 is pressed against the frozen ground surface 13 on the ground surface 13 side, the work in the cavity 12 is performed as compared with the case where the freezing material 14 and the heat insulating material 15 are separately installed. Is simplified. As a result, the construction period can be shortened.

  As described above, the embodiment of the heat insulating coating structure on the frozen ground surface and the method of heat insulating coating on the frozen ground surface according to the present invention has been described, but the present invention is not limited to the above-described embodiment, and departs from the gist thereof. It is possible to change appropriately within the range not to be. For example, in the above-described embodiment, the heat insulating covering structure and the heat insulating covering method of the frozen ground surface 13 in the cavity 12 of the branch junction of the tunnel have been described. However, the present invention can be applied to shafts, tunnels, tunnels, underground storage facilities, and the like. You may apply to the wall of a large underground space.

  Moreover, in above-mentioned embodiment, when constructing a heat insulation coating structure, the heat insulating material 15 is previously attached to the surface of the sheet material 17, the heat insulating panel 16 is shape | molded, and the sheet material 17 side of this heat insulating panel 16 is provided. After the surface is wetted with water, the surface on the sheet material 17 side is set to the frozen ground surface 13 side, and the heat insulating material 15 provided with the sheet material 17 is pressed against the frozen ground surface 13. For example, a belt-shaped covering material may be pressed against the surface of the frozen ground. Furthermore, in the heat insulation coating structure according to claim 1 and the heat insulation coating method according to claim 2 according to the present invention, after the freezing material is attached to the surface of the frozen ground, the heat insulating material is sprayed on the surface of the freezing material. Or you may form a heat insulation coating structure by making it stick.

It is a figure which shows the outline | summary of the tunnel construction method in embodiment of this invention. It is a top view of the branch merge part in the embodiment of the present invention. It is sectional drawing between AA shown in FIG. It is sectional drawing between BB shown in FIG. It is an enlarged view showing the heat insulation coating structure and the heat insulation coating method in embodiment of this invention.

Explanation of symbols

12 Cavity 13 Frozen Ground Surface 14 Freezing Material 15 Heat Insulating Material 17 Sheet Material

Claims (3)

  The surface of the frozen ground formed by the surface of the frozen ground formed around the underground cavity is bonded to the surface of the frozen ground by freezing the surface of the frozen ground by its own water retention. Thermal insulation coating structure.   The surface of the frozen ground formed around the underground cavity is water-fitted with a water-frozen freezing material and freeze-frozen on the frozen ground surface, so that the heat insulating material is pasted through the freezing material. A heat insulating coating method for a frozen ground surface, which is characterized. In the heat insulation coating method of the frozen ground surface of Claim 1,
A method for heat insulating coating of a frozen ground surface, wherein a freeze-fitting material is attached to the heat insulating material in advance.

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