JP2005194774A - Cellular mortar filling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellular mortar filling structure capable of being constructed at a low cost even if the ground is narrow and soft. <P>SOLUTION: The cellular mortar filling structure 20 is formed as a filling by placing cellular mortar on the soft ground 10 having a weak stratum 12 on the strong ground 11. Load of the cellular mortar filling 23 can be supported by a pile foundation by providing the pile foundation 21 to the lower part of the cellular mortar filling 23 up to the strong ground 11, overburden load received by the soft ground 10 can be reduced, and ground subsidence can be prevented. Even if liquefaction temporarily arises, the cellular mortar filling 23 can be supported by the pile foundation 21, and a structure on the cellular mortar filling 23 can be protected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cellular mortar embankment structure using cellular mortar as embankment.

  As for the structure of railroad tracks, it is known that gravel and crushed stone are laid down on a roadbed compacted with a substantially trapezoidal cross section, a roadbed is formed, sleepers are arranged on it, and rails are fixed on the sleepers. It has been. This structure requires time for compacting the roadbed and requires maintenance because it is loosened by rain or the like. Moreover, since the skirt is widened to make it stable and the cross section is substantially trapezoidal, it is difficult to construct a narrow site.

  It is also known that the roadbed is made of concrete, but concrete has a higher specific gravity than the ground of the site, so it could not be applied to soft ground due to the possibility of subsidence.

  In order to make ground subsidence countermeasures light or unnecessary, it is known to use a bubble mortar having a lighter specific gravity than concrete as embankment (for example, see Patent Document 1). FIG. 4 shows the structure of a conventional railroad track using bubble mortar as embankment. In FIG. 4, the side wall 57 is fixed to the H steel 56 driven into the ground 50, the opposing side walls 57, 57 are connected to each other by a tie rod 58, and a foam mortar is placed between the side walls 57, so that the foam mortar embankment 53 is formed. Is formed. The upper surface is covered with roadbed concrete 51, and a track 40 is formed thereon.

Foamed mortar is lightweight and has good fluidity, and it is easy to construct embankments on narrow sites. The foam mortar is applied to the embankment of the viaduct approach, the approach block on the back of the abutment, and the backfilling of underground structures by the open-cut method.
Japanese Patent No. 3233695 Specification

  Conventionally, when a banking mortar embankment is constructed on soft ground (including liquefied ground), steel sheet pile closing work and ground improvement work have been required as countermeasures for soft ground and liquefied ground. When using steel sheet pile cut-off, it is necessary to place steel sheet piles along the periphery of the embankment, and it is also necessary to pierce the ground to a firm ground below the soft layer. Therefore, the construction cost increases. On the other hand, when the ground improvement work is used, there is a problem that the construction cost increases dramatically.

  An object of the present invention is to provide a banking mortar embankment structure that can be constructed inexpensively even in a narrow and soft ground.

  In order to solve the above problems, the invention described in claim 1 of the present invention is such that, as shown in FIG. 1, a bubble mortar is placed on a soft ground 10 having a soft layer 12 on a solid ground 11. In the foam mortar embankment structure (railway structure 20 for railroads) used as the embankment, a pile foundation 21 extending to the solid ground 11 is provided below the foam mortar embankment 23.

  According to the invention described in claim 1, by providing the pile foundation 21 extending to the solid ground 11 at the lower part of the foam mortar embankment 23, the load of the foam mortar embankment 23 can be supported by the pile foundation 21. The upper load received by the ground 10 can be reduced, and ground subsidence can be prevented. Moreover, even when liquefaction occurs, the foam mortar embankment 23 can be supported by the pile foundation 21, and the load can be efficiently transmitted to the pile foundation 21.

  The invention according to claim 2 is characterized in that, in the cellular mortar embankment structure according to claim 1, a protective slab 29 having a compressive strength higher than that of the cellular mortar is provided on the upper part and / or the lower part of the cellular mortar embankment 23. .

  According to the second aspect of the present invention, the protective slab 29 is provided at the upper part and / or the lower part of the foam mortar embankment 23, thereby preventing rain and water in the soft ground 10 from entering the foam mortar weak to water. be able to.

  Further, when an overload is applied to the cellular mortar embankment 23, as shown in FIG. 2, a horizontal compressive force acts on the upper portion of the cellular mortar embankment 23 between the piles, but the protective slab 29 has a higher compressive strength than the cellular mortar. Can be resisted against the horizontal compressive force caused by the overload.

  On the other hand, in the part around the pile foundation 21, the foam mortar embankment 23 receives upward stress from the pile foundation 21, so that a compressive force in the horizontal direction acts on the lower part of the foam mortar embankment 23, but the compressive strength is higher than that of the foam mortar. When the protective slab 29 is provided below the bubble mortar embankment 23, the lower protective slab 29 can resist the horizontal compressive force. Thus, by integrating the foam mortar embankment 23 and the protective slab 29, it is possible to resist the bending force applied to the foam mortar embankment 23, and to efficiently transmit the load to the pile foundation 21.

  The invention according to claim 3 is the cellular mortar embankment structure according to claim 1 or 2, wherein the reinforcing material 24 having a tensile strength higher than that of the cellular mortar is horizontally disposed above and / or below the cellular mortar embankment 23. It is characterized by bar arrangement.

  When an overload is applied to the cellular mortar embankment 23, as shown in FIG. 2, a tensile force in the horizontal direction acts on the lower part of the cellular mortar embankment 23 between the piles. According to the invention of claim 3, the cellular mortar By arranging the reinforcing bars 24 having higher tensile strength in the horizontal direction below the bubble mortar embankment 23, it is possible to resist the horizontal tensile force caused by the overload. On the other hand, in the area around the pile foundation 21, a horizontal tensile force acts on the upper part of the foam mortar embankment 23, but a reinforcing material 24 having a higher tensile strength than the foam mortar embankment 23 is arranged horizontally on the upper part of the foam mortar embankment 23. By streaking, it is possible to resist the horizontal tensile force caused by the overload. For this reason, it is possible to resist the bending force due to the overload applied to the foam mortar embankment 23, and to efficiently transmit the load to the pile foundation 21.

  The invention according to claim 4 is the fixing portion (fixing plate 21a) for fixing the reinforcing material 24 to the pile head of the pile foundation 21 as shown in FIG. 3 in the foam mortar embankment structure according to claim 3. Is provided.

  According to the invention described in claim 4, the reinforcing material 24 is fixed to the pile head of the pile foundation 21 by the fixing portion, whereby the tension applied to the foam mortar embankment 23 is used more efficiently. Can resist bending force due to load.

  According to a fifth aspect of the present invention, in the cellular mortar embankment structure according to the fourth aspect of the present invention, the fixing portion has a flat plate shape and is provided perpendicular to the streaks 24.

  According to the fifth aspect of the present invention, by providing the flat fixing portion perpendicular to the reinforcing material 24, when the fixing portion receives tension from the reinforcing material 24, the fixing portion is perpendicular to the fixing member 24. Since the surface receives stress from the foam mortar embankment 23, the pile head can be stabilized.

  The invention according to claim 6 is the foam mortar embankment structure according to any one of claims 1 to 5, wherein the surface ground 13 immediately below the foam mortar embankment 23 is improved to provide a surface improvement layer 14. It is characterized by.

  According to the invention described in claim 6, by providing the surface improvement layer 14 by improving the surface ground 13 directly below the foam mortar embankment 23, the amount of ground subsidence can be suppressed or the possibility of liquefaction can be reduced. Can be.

  According to the invention described in claim 1, by providing a pile foundation that reaches a solid ground at the lower part of the foam mortar embankment, the load of the foam mortar embankment can be supported by the pile foundation, and the upper load received by the soft ground Can be reduced and land subsidence can be prevented. Also, even if liquefaction occurs, the foam mortar embankment can be supported by the pile foundation, and the load can be efficiently transmitted to the pile foundation.

  According to the invention described in claim 2, by providing the protective slab on the upper and / or lower part of the foam mortar embankment, it is possible to prevent rain and water in the soft ground from entering the foam mortar that is vulnerable to water. . Moreover, by integrating the foam mortar embankment and the protective slab, it is possible to resist the bending force applied to the foam mortar embankment and to efficiently transmit the load to the pile foundation.

  According to the invention described in claim 3, the horizontal tensile force due to the overload is provided by horizontally arranging the reinforcing material having a higher tensile strength than the cellular mortar on the upper and / or lower portion of the cellular mortar embankment. Can resist. For this reason, it can resist the bending force by the overload applied to the foam mortar embankment, and can transmit a load to a pile foundation efficiently.

  According to the fourth aspect of the invention, the bending force due to the overload applied to the foam mortar embankment is more efficiently utilized by fixing the reinforcing material to the pile head of the pile foundation by the fixing portion. Can resist.

  According to the fifth aspect of the present invention, by providing the flat fixing portion perpendicular to the reinforcing material, when the fixing portion receives tension from the reinforcing material, bubbles are generated on the surface perpendicular to the fixing material. Since it receives stress from the mortar embankment, the pile head can be stabilized.

  According to the invention described in claim 6, by reducing the surface subsidence amount or reducing the possibility of liquefaction by improving the surface ground directly under the foam mortar embankment and providing a surface improvement layer. Can do.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a diagram showing a railroad track structure 20 provided by applying the present invention. The railroad track structure 20 includes a pile foundation 21, a bubble mortar embankment 23, a retaining wall 25, a tie rod 28, a protective slab 29, a roadbed concrete 31, and a track 40. The railway track structure 20 is provided on the soft ground 10.

  The soft ground 10 generally has a structure in which a soft layer 12 is provided on a solid ground 11 and a surface ground 13 is overlapped thereon. In order to provide the rail track structure 20 on the soft ground 10, a pile foundation 21 extending from the surface ground 13 to the solid ground 11 below the soft layer 12 is provided.

  The pile foundation 21 supports the railroad track structure 20 together with the surface ground 13, and transmits the load of the railroad track structure 20 to the solid ground 11 below the soft layer 12. It is also possible to improve the surface ground 13 immediately below that supports the railroad track structure 20 to form the surface improvement layer 14. By providing the surface improvement layer 14, the amount of ground subsidence can be suppressed or the possibility of liquefaction can be reduced.

  The pile foundations 21 are provided at predetermined intervals in the length direction of the planned land of the railroad track structure 20. In FIG. 1, two pile foundations 21 are shown that are spaced apart from each other in the width direction of the planned land of the railroad track structure 20. It depends on the weight of the structure 20 and the like.

  The pile head of the pile foundation 21 is provided with a bearing plate 22 as necessary, and a foam mortar embankment 23 is placed thereon. The foam mortar has a lower compressive strength than ordinary concrete, and the reaction force per unit area received from the pile foundation 21 can be reduced by providing the bearing plate 22. When the strength of the bubble mortar is sufficient, or when the pile diameter of the pile head portion of the pile foundation 21 is sufficiently large, the bearing plate 22 is unnecessary. The material of the bearing plate 22 includes a concrete plate and a steel plate, but any other material can be used.

  The retaining wall 25 is provided along both sides of the planned site of the railroad track structure 20. The retaining wall 25 includes an H steel 26 driven along both sides of the planned site of the railroad track structure 20 and a side wall 27 attached to the H steel 26. The side wall 27 serves as a form of the foam mortar embankment 23 and an exterior material for protecting the foam mortar embankment 23 from wind and rain. As the side wall 27, a precast concrete board etc. can be used.

  The tie rods 28 connect the side walls 27 provided on both sides of the planned site of the railroad track structure 20. When the foam mortar embankment 23 is placed between the side walls 27, the side wall 27 receives earth pressure from the foam mortar embankment 23, but the side walls 27 are connected to each other by the tie rods 28. Can resist earth pressure.

The foam mortar embankment 23 is placed on top of the pile foundation 21 and the bearing plate 22 and is placed on the surrounding surface ground 13 or the surface improvement layer 14 and in a space partitioned by retaining walls 25 on both sides. . As the foam mortar, those having a compressive strength of about 15 kgf / cm ² can be used, but not limited to this, any one can be used. A waterproof treatment may be applied between the surface ground 13 or the surface improvement layer 14 and the foam mortar embankment 23.

  A grout material such as concrete is cast on the upper part and / or the lower part of the cellular mortar embankment 23 to form a protective slab 29 having a higher compressive strength than the cellular mortar. The protective slab 29 is integrated with the foam mortar embankment 23 after curing. The protective slab 29 protects the bubble mortar embankment 23 from wind and rain, etc., and also exhibits the action described below.

  When an overload is applied to the foam mortar embankment 23, as shown in FIG. 2, a horizontal compressive force acts on the upper portion between the piles, and a horizontal tensile force acts on the lower portion. By placing a protective slab 29 having a high compressive strength on the top of the foam mortar embankment 23, it is possible to resist a horizontal compressive force caused by an overload.

  On the other hand, in the portion around the pile foundation 21, a horizontal compressive force acts on the lower part of the foam mortar embankment 23, but when a protective slab 29 having a higher compressive strength than the foam mortar embankment is provided on the lower part of the foam mortar embankment 23. The lower protective slab 29 can resist the horizontal compression force.

  Thus, by integrating the foam mortar embankment 23 and the protective slab 29, it is possible to resist the bending force applied to the foam mortar embankment 23, and load is applied to the pile foundation 21 like a beam between pile heads. It can be transmitted efficiently.

  In addition, since the reaction force per unit area which the foam mortar embankment 23 receives from the pile foundation 21 can be reduced by the protective slab 29 below the foam mortar embankment 23, the protection slab 29 is provided instead of the bearing plate 22. Alternatively, it may be provided in addition to the bearing plate 22.

  Further, the reinforcing bars 24 having higher tensile strength than the foam mortar embankment 23 may be arranged in the horizontal direction on the upper part and / or the lower part of the foam mortar embankment 23. Here, as the reinforcing member 24, a reinforcing bar or the like can be used. The reinforcing material 24 may be arranged in the direction of the railroad track structure 20 or in the width direction of the railroad track structure 20. When a reinforcing bar is used as the reinforcing member 24, the reinforcing bar may be subjected to rust prevention treatment.

  When the reinforcing bar 24 is arranged horizontally in the lower part of the foam mortar embankment 23, it is possible to resist the horizontal tensile force caused by the overload. For this reason, it is possible to resist the bending force due to the overload applied to the foam mortar embankment 23, and to efficiently transmit the load to the pile foundation 21. Further, when the reinforcing bar 24 is arranged horizontally in the lower part of the foam mortar embankment 23, a fixing plate 21a for fixing the reinforcing member 24 is provided at the pile head of the pile foundation 21, as shown in FIG. Also good.

  The fixing plate 21a has a vertical flat plate shape, and the reinforcing material 24 is fixed to the fixing plate 21a with a nut or the like (not shown) while vertically passing through the fixing plate 21a. The fixing plate 21a can fix the reinforcing member 24 to the pile head of the pile foundation 21, and more efficiently use the tension of the reinforcing member 24 to resist the bending force due to the overload applied to the foam mortar embankment 23. Can do.

  In addition, by fixing the reinforcing material 24 vertically to the flat fixing plate 21a, when the fixing portion receives tension from the reinforcing material 24, the bubble mortar embankment 23 is formed on a surface perpendicular to the reinforcing material 24 of the fixing plate 21a. Because it receives stress from the pile head, the pile head can be stabilized.

  On the protective slab 29 at the upper part of the foam mortar embankment 23, roadbed concrete 31, gradient concrete 32 or the like is provided if necessary, and a track 40 is provided thereon. The track 40 is composed of a road bed 41, sleepers 42, rails 43 and the like as in the prior art, and a rail 44 is provided as necessary.

  According to the above embodiment, by supporting the weight of the railroad track structure 20 by the pile foundation 21 extending to the solid ground 11, it is possible to reduce the overload applied to the soft layer 12 and prevent ground subsidence. be able to. For this reason, it is not necessary to perform a hard sheet pile closing work or a ground improvement work, and the construction cost of the railway track structure 20 can be reduced. Further, even if liquefaction occurs, the pile foundation 21 supports the railroad track structure 20, and therefore the railroad track structure 20 itself can be prevented from sinking, and the track 40 and the like can be protected. Can do.

  In the present embodiment, the foam mortar embankment structure is applied to the railroad track structure 20, but the present invention is not limited to this, and may be applied to the embankment of an automobile road, or the embankment of a viaduct approach. Of course, it may be applied to the approach block on the back of the abutment and the abutment.

It is a front view which shows the example of the foam mortar embankment structure of this invention. It is a schematic diagram which shows the force concerning the foam mortar embankment structure of this invention. It is a side view which shows the example of the foam mortar embankment structure of this invention. It is an elevational view showing a conventional bubble mortar embankment structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Soft ground 11 Ground 12 Soft layer 13 Surface ground 14 Surface improvement layer 20 Railroad track structure 21 Pile foundation 21a Fixing plate 23 Foam mortar embankment 24 Reinforcement material 29 Protection slab

Claims (6)

  In the foam mortar embankment structure in which the foam mortar is placed on the soft ground with the soft layer on the solid ground, the pile foundation that reaches the solid ground is provided below the foam mortar embankment. The foam mortar embankment structure that does.   The foam mortar embankment structure according to claim 1, wherein a protective slab having a higher compressive strength than the foam mortar is provided on the upper and / or lower part of the foam mortar embankment.   The cellular mortar embankment structure according to claim 1 or 2, wherein a reinforcing bar having a tensile strength higher than that of the cellular mortar is arranged horizontally in an upper part and / or a lower part of the cellular mortar embankment.   The foam mortar embankment structure according to claim 3, wherein a fixing portion for fixing the reinforcing material is provided on a pile head of the pile foundation.   The foam mortar embankment structure according to claim 4, wherein the fixing portion has a flat plate shape and is provided perpendicular to the streaks.   The foam mortar embankment structure according to any one of claims 1 to 5, wherein a surface improvement layer is provided by improving the surface ground immediately below the foam mortar embankment.

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