JP5939710B2 - Ground reinforcement structure - Google Patents

Description

  The present invention mainly relates to a ground reinforcement structure for reinforcing a ground on which a small-scale building, particularly a two-story or three-story detached house is constructed.

  If the ground on which the building is built is required to have a strength that is commensurate with the scale of the building, and if there is a risk of relative subsidence or uneven subsidence or liquefaction, the pile foundation will provide ground support. Measures such as raising or improving the ground are necessary.

  Here, in the case of large-scale structures such as office buildings and condominiums, steel piles and concrete piles are driven into the support layer to reach the support layer, or the pile is formed as a friction pile without being driven into the support layer. Although the structure is constructed so that the head of the building is penetrated into the foundation, if the building scale is small, a simple ground reinforcement method with excellent economic efficiency is desired.

  As a ground reinforcement method suitable for small-scale buildings, a method using small diameter steel pipes is known, and in such ground reinforcement method, pipes that are small diameter steel pipes are placed on the floor of a fabric foundation or a solid foundation. The base is pressed into the ground in a vertical posture so as to form a line along two horizontal directions, and then a fabric foundation or a solid foundation is constructed above the pipe that has been press-fitted.

JP 2007-63915 A

  According to the ground reinforcement method described above, a part of the building load acting via the fabric foundation or solid foundation is supported by the frictional force from the surrounding ground acting on the peripheral surface of the pipe. Compared to the case where the building load is supported only by the ground reaction force from directly below, the overall ground supporting force is greatly improved.

  However, in some cases, the pipe cannot be pressed vertically because it interferes with underground obstacles such as retaining walls and buried cables. To avoid this, the pipe should be installed in a plane position that may interfere with underground obstacles. If you shorten it, change the press-fit pitch, or stop the press-fitting of the pipe at that point, you will not be able to secure the necessary support force, and the support force will be different for each pipe. There was a problem that there is a concern that will occur.

  In particular, when a retaining wall is installed along the boundary of the adjacent land, the ground spreading on the back of the retaining wall may be loosened. In such a situation, the bottom plate of the retaining wall extending below the building is an underground obstacle. As a result, the lack of support force due to the inability to press-fit the pipe vertically was added, causing the problem that the uneven settlement of the building was more likely to occur.

  The present invention has been made in consideration of the above-described circumstances, and even if there are underground obstacles below the foundation, sufficient ground bearing capacity is secured without causing uneven settlement in the building. An object of the present invention is to provide a ground reinforcing structure that can be used.

  In order to achieve the above object, the ground reinforcement structure according to the present invention is the first pile material in a plane area where no underground obstacle exists in the lower part of the foundation constituting the building, as described in claim 1. Is placed in the ground so that the peripheral frictional force acts substantially vertically, and the second pile material is placed on the head in the plane area below the foundation where underground obstacles exist. The head of the first pile material and the head of the second pile material are arranged obliquely in the ground so that the horizontal position is positioned in the plane range and the peripheral frictional force acts. Are connected to a load transmission material arranged substantially horizontally in the ground.

  Further, the ground reinforcement structure according to the present invention is arranged such that the second pile material is separated from the first pile material on the head side and close to the first pile material on the tip side. is there.

  Moreover, the ground reinforcement structure according to the present invention includes a plurality of the first pile members arranged in a row and connects their heads to the load transmission member, respectively, and among the first pile members, The second pile material is connected to a projecting portion of the load transmission material extending horizontally from the outermost pile material.

  Moreover, the ground reinforcement structure which concerns on this invention interposes the raising / lowering mechanism in the head vicinity of the said 2nd pile material, or between this 2nd pile material and the said load transmission material.

  In the ground reinforcement structure according to the present invention, measuring means capable of measuring the deflection of the load transmitting material is disposed on the load transmitting material.

  The pile material in the conventional ground reinforcement method using thin steel pipes supports the vertical load of the building acting from above through the foundation with the frictional force from the surrounding ground acting on the peripheral surface. In order to avoid unforeseen circumstances due to the rotation of the material, it is necessary to press-fit while keeping the vertical posture as much as possible.

  However, due to the presence of underground obstacles, the pile material cannot be pressed vertically, and as a result, if the pile material at that location is shortened or omitted, the overall ground bearing capacity will be insufficient. As mentioned above, there are also concerns that the buildings will cause uneven settlement.

  The present applicant has made the present invention described above as a result of conducting research with a focus on how to prevent a decrease in ground bearing capacity and uneven settlement of buildings when there are underground obstacles. Has been reached.

  That is, in the ground reinforcement structure according to the present invention, the first pile material is arranged almost vertically and on the peripheral surface in the plane area where there are no underground obstacles below the foundation, as in the conventional ground reinforcement method. Although it is arranged in the ground so that the friction force acts, the second pile material is placed in the plane area where the underground obstacle exists so that the horizontal position of the head is positioned in the plane area. It arrange | positions diagonally in the ground so that a surface friction force may act, and the head of a 1st pile material and the head of a 2nd pile material are connected to a load transmission material in this state.

  If it does in this way, the vertical load of the building which acts on the head of the 2nd pile material via the foundation will be the slant upward peripheral frictional force and load transmission material which occur along the material axis direction of the 2nd pile material In other words, the second pile material balances with the horizontal compression reaction force or tensile reaction force generated along the material axis direction of the material. In other words, the second pile material causes rotational deformation that occurs because the material axis direction is not vertical from the load transmission material. The vertical load of the building is supported by the friction force from the surrounding ground acting on the peripheral surface while being prevented by the reaction force of the surroundings, and thus even if there are underground obstacles below the foundation, It is possible to secure a sufficient ground supporting force without causing uneven settlement.

  Buildings are mainly small buildings, especially 2-story or 3-story detached houses.

  Whether the foundation is a fabric foundation or a solid foundation, in the case of a fabric foundation, along the rising part, in the case of a cloth foundation, the first pile material over the entire horizontal region The structure which arrange | positions a 2nd pile material in a ground in a ground can each be employ | adopted.

  The 1st pile material and the 2nd pile material can be comprised with the pipe which is a small diameter steel pipe.

  The load transmitting material can transmit a compressive force or a horizontal force from the second pile material to the head of the first pile material, and can generate a compression reaction force or a tensile reaction force in the first pile material. As long as it can be arbitrarily configured, for example, it can be composed of the same members as the first pile material and the second pile material.

  As for the arrangement of the first pile material and the second pile material in the ground, any arrangement may be used as long as the peripheral frictional force acts from the surrounding ground on the circumferential surface of the pile material. By attaching the first pile material or the second pile material to the leader of the pile driving machine and maintaining a vertical or oblique posture, and applying a rotational force and a propulsive force in such a state, It is possible to adopt a method in which the two pile materials are rotationally press-fitted into the ground and arranged in the ground.

  Underground obstacles are those that cannot or cannot be penetrated when placing the first pile material vertically in the ground, such as the bottom plate of the retaining wall, piping, buried cultural property Etc. are included.

  As long as the second pile material is arranged obliquely so as to avoid interference with such underground obstacles, the angle at which the second pile material is arranged is arbitrary, and the head side is the first pile. It is optional whether the tip side is moved closer to the first pile material or the head side is moved closer to the first pile material and the tip side is moved away from the first pile material. In the former configuration, that is, if the second pile material is arranged so as to be separated from the first pile material on the head side and close to the first pile material on the tip side, the load generated in the load transmission material is reduced. Since it becomes a tensile force, it becomes unnecessary to consider buckling and the like, and it becomes easy to handle structurally.

  The plane area where there are underground obstacles may be a plane area where piles cannot be placed vertically due to physical interference. It is also desirable for safety to include a flat area that may adversely affect medium obstacles. In this case, the plane range in which no underground obstacle exists is a range in which the pile material can be arranged vertically and the pile material and the underground obstacle are not adversely affected during the construction of the pile material.

  The first pile material, the second pile material, and the load transmission because the horizontal compression reaction force or tensile reaction force must be transmitted from the first pile material to the second pile material via the load transmission material The material needs to be arranged along the same vertical construction surface, but as long as these members are arranged along the same vertical construction surface, the relative positions of the first pile material and the second pile material The relationship is arbitrary, and if there are underground obstacles directly under the center of the building, the second pile material is placed below the foundation located in the center of the building, and the first piles on both sides thereof It is only necessary to arrange each material, and if an underground obstacle exists obliquely below instead of directly under the building, the second pile material is placed below the foundation on the side where the underground obstacle exists. What is necessary is just to arrange | position and arrange | position a 1st pile material on the opposite side.

  For example, in the case of a fabric foundation, the first pile material, the second pile material, and the load transmission material are disposed below the fabric foundation in the same row, and the first pile material is formed along the vertical plane formed by them. Although it is desirable in terms of structure or construction to arrange the two pile materials diagonally, the vertical construction surface formed by the first pile material, the second pile material, and the load transmission material is originally the material axis of the building or foundation In the case of a fabric foundation, the first pile material and the second pile material may be arranged on different fabric foundations.

  Moreover, it is also arbitrary whether the 1st pile material is made into a single structure or a multiple piece structure.

  As a specific configuration example regarding the relative positional relationship between the first pile material and the second pile material, for example, a plurality of first pile materials are arranged in a row along the material axis direction of the fabric foundation, A configuration is conceivable in which the head is connected to the load transmission material, and the second pile material is connected to the overhanging portion of the load transmission material extending horizontally from the outermost pile material among the first pile materials. However, in this configuration, the bottom plate of the retaining wall installed along the boundary of the adjacent land extends below the building so that it can be seen on a flat-bed site made by cutting or embedding the slope. Among them, the foundation on the retaining wall side has an optimum configuration when the bottom plate of the retaining wall becomes an underground obstacle and the first pile material cannot be press-fitted vertically.

  As described above, according to the present invention, even if there is an underground obstacle below the foundation, the vertical load of the building is supported with sufficient ground supporting force without causing uneven settlement in the building. However, if an elevating mechanism is interposed near the head of the second pile material or between the second pile material and the load transmission material, the elevating mechanism is interposed between the second pile material. By taking the reaction force from the ground, it is possible to load the load transmitting material and the foundation located directly above it upwards, so the ground spreading on the back of the retaining wall will loosen, causing inconsistent displacement in the building It is also possible to prevent this.

  The lifting mechanism can be appropriately configured using, for example, a jack base used for a leg portion of a single-tube scaffold or a similar one, and can also be configured by a hydraulic jack or an electric motor.

  The non-uniform displacement that occurs in the building due to the loose ground on the back of the retaining wall can be grasped by measuring the displacement of the building itself as well as by measuring the rotation and movement of the retaining wall or the ground stress. By utilizing the fact that the load transmission material is bent and arranging a measuring means capable of measuring the deflection in the load transmission material, the lifting mechanism operates according to the magnitude of the deflection generated in the load transmission material. Thus, it is possible to more reliably manage the non-uniform displacement of the building.

  The measuring means can be configured by attaching strain gauges to the lower surface and the upper surface of the inner peripheral surface of a load transmitting material formed of, for example, a pipe.

The vertical sectional view of the ground reinforcement structure 1 concerning this embodiment. 1 is an overall plan view of a ground reinforcement structure 1. FIG. The whole perspective view of the ground reinforcement structure 1. FIG. Explanatory drawing which showed the effect | action of the ground reinforcement structure 1. FIG. The vertical sectional view showing the ground reinforcement structure concerning a modification. It is the figure which showed the ground reinforcement structure which concerns on another modification, (a) is a top view, (b) is a vertical sectional view which follows the AA line. The vertical sectional view showing the ground reinforcement structure concerning another modification.

  Hereinafter, embodiments of a ground reinforcement structure according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a vertical sectional view showing a ground reinforcement structure according to this embodiment. As can be seen from the figure, in the ground reinforcement structure 1 according to the present embodiment, the retaining wall 3 is installed at the boundary of the adjacent land of the site where the building 2 is located, and the bottom plate 4 of the retaining wall extends below the building 2. It is applied to the situation, and below the fabric foundation 5 constituting a part of the building 2, the pipe 6 as the first pile material is placed in the ground 7 so that the peripheral frictional force acts almost vertically. And the pipe 8 as the second pile material is arranged in the ground 7 so that the peripheral frictional force acts diagonally, and the pipe 6 and the pipe 8 have their heads These are connected to load transmission members 9 arranged almost horizontally in the ground 7.

  Since the pipe 6 is separated from the bottom surface 4 of the retaining wall 3 which is an underground obstacle by a sufficient horizontal distance as shown in FIG. 2, the pile material is arranged vertically. It is arranged in a range in which the pile material and retaining wall 3 are not adversely affected during the construction of the pile material, and among the outer peripheral foundations constituting the fabric foundation 5, the outer peripheral foundation orthogonal to the retaining wall 3 It consists of 17 in total, 10 on the inner foundation, 5 on the inner foundation, 2 on the outer circumferential foundation parallel to the retaining wall 3 and not connected to the inner foundation.

  On the other hand, the pipe 8 has a horizontal position of their heads in the plane range where the underground obstacles shown in the figure exist, that is, the bottom plate 4 of the retaining wall 3 exists, so that the pile material cannot be arranged vertically, Or, since it is not separated by a sufficient horizontal distance, it is arranged so as to be positioned in a plane range where the pile material and the retaining wall 3 may be adversely affected by the disturbance of the ground during construction of the pile material, and the fabric foundation 5 Out of the outer peripheral foundations comprising 4 on the outer circumferential foundation orthogonal to the retaining wall 3, 2 on the inner foundation, and 2 on the outer circumferential foundation parallel to the retaining wall 3 where the inner foundation is not connected. It consists of eight.

  As can be clearly seen in FIG. 3, the pipe 6, the pipe 8, and the load transmission member 9 are classified into five sets of structures 11 a to 11 e that are connected to each other along the five different vertical planes. In FIG. 2, the leftmost structure 11a is along the vertical plane including the material axis of the outermost foundation located in the uppermost position, and has five pipes 6 arranged in a row. The two heads 8 are connected to the load transmitting member 9 and two pipes 8 are connected to the overhanging portion of the load transmitting member 9 extending horizontally from the outermost pipe 6. It is arranged obliquely so as to be separated from the pipe 6 on the part side and close to the pipe 6 on the tip side.

  Similarly, the structure 11b is along the vertical construction surface located second from the top in FIG. 2, and one pipe 6 and one pipe 8 are connected to the load transmission member 9. In FIG. 2, the structure 11c is along the third vertical composition plane from the top including the material axis of the internal foundation, and loads the heads of the five pipes 6 arranged in a row. Each of the two pipes 8 is connected to the projecting portion of the load transmitting material 9 extending horizontally from the outermost pipe 6 and connected to the transmitting material 9, and the structure 11d is the fourth from the top in FIG. 2 and is formed by connecting one pipe 6 and one pipe 8 to a load transmitting member 9, and the structure 11e is the lowermost peripheral foundation in FIG. Along the vertical construction plane including the material axis, the heads of the five pipes 6 arranged in a row are transferred to the load. Each of the pipes 8 in each of the structures 11b to 11e is connected to the material 9 and two pipes 8 are connected to the projecting portion of the load transmitting material 9 extending horizontally from the pipe 6 at the outermost position. It is arranged obliquely so as to be separated from the pipe 6 on the head side and close to the pipe 6 on the tip side.

  The pipes 6 and 8 and the load transmission material 9 can be formed of, for example, steel pipes having a diameter of about 50 mm and a wall thickness of about several mm. Each head of the pipes 6 and 8 and the load transmission material 9 are, for example, They can be appropriately connected using an orthogonal clamp or a universal clamp (both not shown) used for assembling the single pipe scaffold.

  The structures 11a to 11e may be connected to each other as necessary.

  In order to construct the ground reinforcement structure 1 according to the present embodiment, a work groove (not shown) is formed in advance on the ground surface of the ground 7 so as to match the planar shape of the pile foundation 5 shown in FIG. Next, the pipe 6 is rotationally press-fitted vertically from the bottom surface of the working groove, and the pipe 8 is obliquely rotationally press-fitted, whereby the pipes 6 and 8 are disposed in the ground 7.

  Next, with respect to the structures 11a, 11c, and 11e, the load transmitting material 9 is temporarily held horizontally using the recessed space of the working groove, and in this state, the pipe 6 is connected to the head of the pipe 6 by using an orthogonal clamp. The heads of the pipe 6 and the pipes are connected to the heads of the pipes 8 by using universal clamps, and the structures 11b and 11d are appropriately excavated from the ground surface to temporarily hold the load transmission material 9 in the same manner. Connect the 8 heads in the same way.

  When the construction of the structures 11a to 11e is completed, the work foundation 5 is constructed after the working grooves are backfilled, gravel is laid, and discarded concrete is struck.

  In the ground reinforcement structure 1 according to the present embodiment, the ground 7 is arranged so that the pipe 6 is substantially vertical and the peripheral frictional force acts on the plane area where the underground obstacle does not exist below the fabric foundation 5. In the plane area where the underground obstacle exists, the pipe 8 is ground 7 so that the horizontal position of the head thereof is positioned in the plane area and the peripheral frictional force acts. In this state, the head of the pipe 6 and the head of the pipe 8 are connected to the load transmission member 9 respectively.

  If it does in this way, while the load of the building 2 loaded via the cloth foundation 5 from the upper direction of the pipe 6 will be supported by the frictional force from the surrounding ground which acts on the surrounding surface of the pipe 6, the head of the pipe 8 will be supported. The load of the building 2 loaded via the fabric foundation 5 from above is obliquely upward circumferential frictional force generated along the material axis direction of the pipe 8 and horizontal direction generated along the material axis direction of the load transmitting material 9 The pipe 8 balances with the tensile reaction force of the building 2. In other words, the pipe 8 is prevented from being deformed by the tensile reaction force from the load transmitting material 9 due to the fact that the axial direction of the material axis is not vertical. The vertical load of is supported.

  FIG. 4 shows the support state of the vertical load of the building 2 for each of the structures 11a, 11c, 11e and the structures 11b, 11d.

  As explained above, according to the ground reinforcement structure 1 according to the present embodiment, the vertical load of the building 2 loaded from above the head of the pipe 8 via the fabric foundation 5 is applied in the material axis direction of the pipe 8. The vertical load from the building 2 is prevented while the pipe 8 is prevented from being rotated and deformed in order to balance by the diagonally upward circumferential frictional force generated along the horizontal axis and the horizontal tensile reaction force generated along the axial direction of the load transmitting material 9. Is supported.

  Therefore, even if the bottom slab 4 of the retaining wall 3 that is an underground obstacle exists below the fabric foundation 5, it is necessary to sufficiently secure the ground supporting force without causing uneven settlement in the building 2. Is possible.

  In the present embodiment, the case where the foundation of the building is the fabric foundation 5 has been described, but it goes without saying that the foundation can be similarly applied to a solid foundation.

  Further, in this embodiment, the pipes 8 are arranged obliquely so as to be separated from the pipes 6 on the head side and close to the pipes 6 on the front end side, but as shown in FIG. In the case where the piping 51 is buried as an underground obstacle, the pipes 8 may be arranged obliquely so as to be close to the pipe 6 on the head side and away from the pipe 6 on the tip side. Absent.

  Even in such a configuration, the force generated in the load transmission member 9 is substantially the same as that of the above-described embodiment except that the force is a compressive force, and thus the description thereof is omitted here.

  Moreover, although this embodiment demonstrated the case where structure 11a, 11c, 11e was comprised along the vertical composition plane containing the outer peripheral foundation of the fabric foundation 5, and the material axis of an internal foundation, structure 11b, 11d was demonstrated. As is the case, the structure composed of the first pile material, the second pile material, and the load transmission material in the present invention may be disposed below the foundation and connected along the same vertical construction surface. In the case where the foundation is a cloth foundation, it is not necessary to be configured along a vertical plane including the material axis of the cloth foundation.

  FIG. 6 shows a case in which the building 2 is inclined in a plane by 45 degrees with respect to the retaining wall 3, and the pipe 6 connected to the pipe 8 through the load transmission material 9 is a pipe in a diagonal position. However, there is no problem with this configuration.

  Although not particularly mentioned in the present embodiment, as shown in FIG. 7, a jack mechanism 71 as an elevating mechanism constituted by using a jack base used for a leg portion of a single pipe scaffold as a head of a pipe 8. If the structure is connected to the load transmission material 9 via the jack, the jack mechanism 71 is operated, so that the reaction force is taken from the ground 7 via the pipe 8, and the load transmission material 9 is further positioned immediately above it. Since the fabric foundation 5 can be loaded upward, it is possible to prevent a situation in which the ground spreading on the back surface of the retaining wall 3 is loosened and the building 2 is caused to be displaced indistinctly.

  Further, in this configuration, a strain gauge (not shown) as a measuring means is attached to the lower surface and the upper surface of the inner peripheral surface of the load transmission material 9 so that the deflection amount of the load transmission material 9 can be measured. If it does, since the operation of the jack mechanism 71 can be performed based on the measurement result, the non-uniform displacement of the building 2 can be managed more reliably.

1 Ground reinforcement structure 2 Building 3 Retaining wall 4 Bottom plate (underground obstacle)
5 Fabric foundation (foundation)
6 Pipe (first pile material)
7 Ground 8 Pipe (second pile material)
9 Load transmission material 51 Piping (underground obstacle)
71 Jack mechanism (lifting mechanism)

Claims (5)

The first pile material is arranged in the ground so that a peripheral frictional force acts on the plane area where no underground obstacle exists in the lower part of the foundation constituting the building, and the foundation The second ground is placed in the plane area where the underground obstacle exists in the lower part of the ground so that the horizontal position of the head is positioned in the plane area and the peripheral frictional force acts. The ground reinforcement is characterized in that it is disposed obliquely inside and the head of the first pile material and the head of the second pile material are connected to a load transmission material disposed substantially horizontally in the ground. Construction. The ground reinforcement structure according to claim 1, wherein the second pile material is disposed so as to be separated from the first pile material on a head side and to be close to the first pile material on a tip side. A plurality of the first pile members are arranged in a row and their heads are connected to the load transmitting member, respectively, and the first pile member extends horizontally from the outermost pile member. The ground reinforcement structure of Claim 2 which connected the said 2nd pile material to the overhang | projection site | part of the load transmission material. The ground reinforcement structure as described in any one of Claim 1 thru | or 3 which interposed the raising / lowering mechanism between the head vicinity of the said 2nd pile material, or between this 2nd pile material and the said load transmission material. The ground reinforcing structure according to claim 4, wherein measuring means capable of measuring the deflection of the load transmitting material is disposed on the load transmitting material.

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