JP2006022608A - Arrangement method of horizontal supporting force reinforcing material in foundation formation of reinforcing ground and foundation body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the optimum arrangement method of reinforcing materials of a foundation body on which a horizontal force acts. <P>SOLUTION: A hole is drilled from the excavated face of a foundation into the natural ground 4. After a high rigid reinforcing member 3 is anchored to the natural ground 4 in the drilled hole, the basal end of the reinforcing member is anchored in the foundation main body 2 to construct a foundation body 1. In this ground reinforcing type foundation formation, the reinforcing member 3 is placed from the foundation main body 2 to the horizontal outside, the reinforcing member 3 is arranged in the position where at a proof stress increase is maximum when a horizontal force acts on the foundation body 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an arrangement method of a horizontal supporting force type reinforcing material and a foundation body in formation of a foundation of a ground reinforcing type that reinforces a horizontal supporting force of a foundation for construction and civil engineering.

  There is a technique for strengthening the supporting force by using a foundation body in which reinforcing members made of steel bars are arranged radially around the deep foundation body (see Patent Document 1).

  The basic body will be described. In FIGS. 13 and 14, reference numeral 1 denotes a basic body in which a reinforcing material 3 made of steel bars is arranged around the deep foundation basic body 2. A number of reinforcing members 3 extend radially from the base body 2 in the horizontal direction and are arranged at predetermined intervals in the axial direction, all of which are fixed in the surrounding natural ground 4.

  Next, rebar assembly of the foundation body 2 is performed while avoiding the base end portion of the reinforcing member 3 protruding from the natural ground 4. Thereafter, the fixing plate is fixed to the base end portion of the reinforcing member 3 inside the bar arrangement. Thus, if concrete is cast in the foundation main body 2 after fixing the base end part of each reinforcement material 3 to reinforcement, the foundation body 1 like FIG.13 and FIG.14 will be formed.

  Next, the operation of the base body 1 formed as described above will be described.

  The reinforcing material 3 is firmly integrated with the natural ground 4 because the adhesion of the solidifying agent filled between the natural ground 4 acts as a fixing force to the natural ground 4 and increases the ground strength around the reinforcing material 3. Since the base end portion is fixed to the reinforcing bar of the base body 2, the base end part is also rigidly coupled. As a result, the foundation body 1 functions as an integral foundation including the surrounding ground 22, and the acting surface of the shear resistance s when the pulling force Fv acts on the foundation body 2 is as shown in FIG. It becomes the large-diameter virtual support surface 23 connecting the tips of the two. For this reason, the working area of the shear resistance s is remarkably enlarged, and the supporting force against the pulling force is greatly increased.

On the other hand, the support structure for the horizontal force Fh is also reinforced as shown in FIG. That is, the working surface of the passive earth pressure p1 and the elastic ground reaction force p2 expands to a virtual support surface 24 having a semicircular cross section connecting the tips of the reinforcing members 3 located on the left half of the base body 2 in the figure, Since the ground 22 is strengthened by the reinforcing material 3, the range of the formation B where the elastic ground reaction force p2 is obtained also expands upward. Further, the pull-out resistance a of the reinforcing member 3 located in the right half of the basic body 2 in the drawing works as a supporting force. Accordingly, the base body 1 has a supporting force for the horizontal force Fh.
Japanese Patent Publication No. 5-40085

  However, in the above conventional example, the optimum arrangement of the reinforcing material that suppresses the collapse of the foundation main body due to the horizontal force caused by an earthquake or the like has been unclear.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a reinforcing material arranging method and a basic body that can optimize the arrangement of reinforcing materials when a horizontal force is applied to reduce the size of the basic body.

According to a first aspect of the present invention, a hole is drilled from a base excavation surface into a natural ground, and a stiff reinforcing material is fixed in the natural ground in the drilling hole, and then a base end portion of the reinforcing material is fixed in the basic body. In the ground reinforcing type foundation forming method for constructing the foundation body, the reinforcing material is driven from the foundation main body toward the outside in the horizontal direction, and the tensile stress, compressive stress and shear on the ground are applied to the reinforcing material. Strength increase ΔPs calculated by the following formula (1), which increases the resistance of the ground to the horizontal force acting on the foundation by structurally sharing a part of the stress,
ΔPs = Σ (Smax _i · cos Θ + Nmax _i · sin Θ) (1)
Where Smax _i is the maximum shear force of the reinforcing material,
Nmax _i is the maximum axial force of the reinforcing material,
Θ is the angle formed by the horizontal line perpendicular to the direction of the horizontal force and the direction in which the reinforcing material is placed
Every time,
i corresponds to the number of reinforcing materials (i ≧ 1)
Strength which is calculated by the following formula (2) and formula (3), which increases the resistance of the ground to the horizontal force acting on the foundation by restraining the tensile strain and compression strain generated in the ground by the reinforcing material. Increment ΔPr,
ΔPr = Σ (Nmax _i · cos Θ−Smax _i · sin Θ) · tan Φ · f (Θ) (2)
f (Θ) = [ ² cos ² (Θ−45 ° + Φ / 2) − (1-sinν)] / (1 + sinν) (3)
Where Φ is the internal friction angle of the natural ground on which the foundation is built,
ν is the arrangement of the reinforcing material when it is assumed that a horizontal force acts on the foundation body based on the dilatancy angle.

  In a second aspect based on the first aspect, the reinforcing material is disposed at the angle Θ at which a maximum value obtained by adding at least the yield strength increments ΔPs and ΔPr is generated.

  In a third aspect based on the first aspect, the reinforcing member is disposed at least in the minimum principal strain direction when the horizontal force acts as a tensile force on the reinforcing member.

  According to a fourth invention, in any one of the first to third inventions, the reinforcing member is disposed at least in the maximum principal strain direction when the horizontal force acts as a compressive force on the reinforcing member.

  According to a fifth invention, in the invention according to any one of the first to fourth inventions, the reinforcing material is arranged on the outer peripheral surface of the foundation main body at a ratio of approximately one per 2 square meters.

  6th invention consists of the base main body which excavated and built the natural ground, and the rod-shaped reinforcement material which is cast in the horizontal direction outer side from the said basic main body, and is fixed in the said natural ground, horizontal force is When the horizontal force acts as a tensile force on the reinforcing material in the ground reinforcement type foundation that acts, at least one of the reinforcing materials is arranged so as to coincide with the minimum principal strain direction of the natural ground. And when the said horizontal force acts as a compressive force on the said reinforcing material, at least 1 of the said reinforcing material is arrange | positioned so that it may correspond with the largest main strain direction of the said natural ground.

  7th invention consists of the foundation main body which excavated and built the natural ground, and the rod-shaped reinforcement material which is driven outside from the basic body and is fixed in the natural ground, and horizontal force acts on it. In the ground reinforcement type foundation body, the foundation body rotates around a rotation center in the foundation body by a horizontal force, and when the horizontal force acts as a compressive force on the reinforcement member, the reinforcement member is used as the foundation body. And at least one of the reinforcing members is disposed so as to coincide with the maximum principal strain direction of the natural ground, and the horizontal force acts as a tensile force on the reinforcing member. In this case, the reinforcing material is arranged in the horizontal direction from the foundation body, and at least one of the reinforcing materials is arranged so as to coincide with the minimum principal strain direction of the natural ground.

  According to an eighth invention, in the sixth or seventh invention, the horizontal cross-sectional shape of the basic body is any of a circular shape, an elliptical shape, an oval shape, or an annular cross-sectional shape thereof.

  Therefore, in the present invention, since the reinforcing material can be disposed at a position where the increase in the proof stress of the natural ground is maximized, the foundation body of the basic body can be downsized due to the reinforcing effect of the reinforcing material. For this reason, cost reduction and shortening of a construction period can be aimed at.

  In addition, when tensile force acts on the reinforcing material, the reinforcing material is arranged in the direction in which the minimum principal stress of the natural ground is generated, so that the reinforcing material arrangement that maximizes the proof stress increment ΔPr can be achieved, thereby reducing the size of the foundation body. Can be planned.

  On the other hand, when the compressive force acts on the reinforcing material, the reinforcing material is arranged in the direction in which the maximum principal stress of the natural ground is generated, so that the reinforcing material can be arranged to maximize the proof stress increment ΔPr, and the foundation body can be downsized. Can be planned.

  By arranging the reinforcing material on the outer peripheral surface of the foundation main body at a ratio of about 1 per 2 square meters, the reinforcing effect on the number of reinforcing materials can be enhanced.

  In addition, since the horizontal cross-sectional shape of the foundation body is one of a circular shape, an oval shape, an oval shape, or an annular cross-sectional shape thereof, the optimum cross-sectional shape may be set according to the shape of the pier supported by the foundation body. In addition, by making an annular cross section, the remaining soil can be processed in the hollow portion inside, and the labor of the remaining soil processing can be reduced.

  Hereinafter, the present invention will be described focusing on differences from the conventional foundation forming method and the foundation shown in FIGS.

  As shown in FIGS. 1 and 2, a foundation body 1 to which the present invention is applied includes a deep foundation foundation body 2 constructed in a vertical direction, and a reinforcing material 3 extending radially from the foundation foundation body 2 in a horizontal direction. Consists of. In the present embodiment, the basic body 1 is described as being built on an inclined land, but it goes without saying that the same is true even if it is built on a flat ground.

  A horizontal force acting due to an earthquake or the like and / or a bending moment for tilting the foundation body 2 acts on the foundation body 1 from the mountain side to the valley side, and the weight of the bridge supported by the foundation body 1 acts. As shown in FIG. 3, the reinforcing member 3 composed of a steel rod grouted with mortar on the peripheral surface mainly reinforces the supporting force of the foundation body 1 by a tensile force as shown in FIG. 3. 3a and a compression reinforcing material 3b that reinforces the supporting force of the base body 1 by a compressive force. The reinforcing effect of the reinforcing member 3 includes a structural effect that resists structurally and a reinforcing earth effect that restrains deformation and distortion of the ground and improves the yield strength of the ground. Therefore, the tensile reinforcement member 3a on the mountain side can be expected to have a tensile structure effect and a tensile reinforcement soil effect, and the compression reinforcement member 3b on the valley side can be expected to have a compression structure effect and a compression reinforcement soil effect.

  As shown in FIG. 1 and FIG. 2, when the foundation body 1 of the present invention is formed on an inclined ground, the reinforcing material 3 is different in the number of the mountain side and the valley side, and the ground mountain 4 is different from the foundation body 1. You may make it install more reinforcing materials 3 in the mountain side which can be covered to high.

  According to an experiment using a model, the reinforcing member 3 is preferably constructed at a deeper position in the natural ground, that is, at the lower end side of the foundation body 1 as shown in FIG. 1, thereby obtaining a higher reinforcing effect. It is done.

Further, according to the simulation calculation shown in FIG. 4 and FIG. 5 based on the calculation method of the reinforcing effect described later and the result thereof, the reinforcing material 3 is arranged at a ratio of about one square meter on the outer peripheral surface of the base body 2. In this case, the largest reinforcing effect can be efficiently obtained with respect to the number of the reinforcing members 3. That is, the arrangement density of the reinforcing members 3 on the outer peripheral surface of the base body 2 is set to 1/4 m ² , 1 as shown in the simulation model shown in FIG.
And present / 2m ^2, one /1.5M ^2, sequentially, when performed by increasing, as the results shown in FIG. 5, after exceeding the one density of almost two square meters, the reinforcing effect Since the increase in size is almost horizontal, it can be seen that it is most efficient to arrange the reinforcing members 3 at a ratio of about 1 in 2 square meters.

  Next, the operation of the reinforcing material 3 will be described.

  The reinforcement effect on the foundation 1 includes structural effects caused by structurally sharing a part of the tensile stress, compressive stress and shear stress on the natural ground 4 and the tensile strain generated in the natural ground 4. / There are two possible effects of reinforcing soil, which restrains compressive strain with the reinforcing material 3 and increases the strength and rigidity of the natural ground 4 by increasing the restraining pressure.

  In the present invention, by specifying the direction in which the reinforcing material 3 is disposed, the mechanical properties of the surrounding natural ground 4 can be improved and the reinforcing effect can be enhanced.

  Specifically, when a horizontal force or bending moment from the mountain side to the valley side is applied to the foundation body 1, the mountain side reinforcing material 3 serves as the tension reinforcing material 3 a and the ground side 4 on the mountain side of the foundation body 1 is used as the foundation body 1. Has the effect of pulling to the side. According to FIG. 6 in which the effect of the tensile reinforcing material 3a is evaluated by the placement angle Θ, a large reinforcing soil effect appears in the range where the placement angle Θ is small, that is, the side surface portion of the foundation body 1, and the angle Θ becomes large and the mountain side is increased. As a result, the reinforced soil effect decreases. On the other hand, the structural effect increases as the angle Θ increases and becomes maximum in the direction parallel to the horizontal force acting direction. Here, the placement angle Θ is an angle formed by a horizontal line perpendicular to the direction of application of the horizontal force and the placement direction of the reinforcing member 3.

In a large range of the reinforced soil effect, the absolute value (expansion) of the minimum strain increment Δε ₃ is suppressed to a small value by the reinforcing material 3 when the ground 4 is sheared, so that the minimum principal stress σ ₃ ′ increases. This promotes an increase of the shear strength (σ ₁ ′ −σ ₃ ′) / 2 with respect to the maximum principal stress σ ₁ ′, and strengthens the natural ground 4. Thus, the reinforced soil effect is a ground improvement effect by suppressing positive dilatancy (volume distortion).

  Therefore, the bearing capacity increase by the reinforced soil effect cannot be obtained when the direction in which the reinforcing material 3 is disposed coincides with the direction in which the reinforcing material 3 does not expand and contract, and the increment of the minimum main strain that causes the ground 4 to undergo shear failure due to the horizontal force. The effect is greatest when the tensile reinforcing material 3a is disposed so as to coincide with the direction Θ. Specifically, from the relationship between the placement angle Θ shown in FIG. 6 and the effect margin, the effect increases when the placement angle Θ of the tensile reinforcement 3a is 10 ° to 30 ° with 20 ° being the maximum. In the total reinforcing effect including the structural effect and the reinforcing soil effect, a large effect is produced when the placing angle Θ is 20 ° to 50 ° with a maximum of about 35 °. Here, the effect due to the placement angle Θ of the reinforcing material is generated symmetrically with respect to the horizontal force. Therefore, the appropriate placement angle of the tensile reinforcing material 3a from the viewpoint of the total reinforcing effect of the tensile reinforcing material 3a is approximately 35 °. The maximum is 20 ° to 50 ° and the maximum is approximately 145 ° to 130 ° to 160 °.

On the other hand, the compression reinforcing material 3b arranged on the valley side with respect to the horizon has the performance of distributing and supporting the compressive force acting on the ground from the foundation body 2 and exhibiting the reinforcing effect. The compression structure effect is defined as a force directly shared by the compression reinforcing material 3b, and the compression reinforcement soil effect is exhibited by reducing the maximum principal stress σ ₁ ′ of the ground. This compression-reinforced soil effect is most effective when the reinforcing material 3b is driven in the maximum principal strain direction of the ground. According to FIG. 7 in which the effect of the compression reinforcing material 3b was evaluated by the placement angle Θ in the same manner as the tensile reinforcement 3a, the placement angle Θ was in the range of −40 ° to −70 ° with about −55 ° being the maximum, that is, Reinforced soil effect appears at the side of the foundation, and the reinforced soil effect decreases as the placement angle Θ increases and approaches the valley side. On the other hand, the structural effect increases as the driving angle Θ increases and becomes maximum in the valley side direction parallel to the horizontal force acting direction. It can be seen that in the total reinforcement effect of the structure effect and the reinforcing soil effect, a large effect is produced when the placing angle Θ is approximately −65 ° to −90 ° to −90 °. Therefore, in the same manner as the tensile reinforcement member 3a, the appropriate placement angle of the compression reinforcement member 3b from the viewpoint of the total reinforcement effect of the compression reinforcement member 3b is about −65 ° and about −115 ° at the maximum, from −50 ° to − 130 °.

  As apparent from FIGS. 6 and 7, as the effect margin of the reinforcing soil effect, the tensile reinforcing material 3a is larger than the compression reinforcing material 3b, and from the point of the reinforcing soil effect, a large amount of the tensile reinforcing material 3a is provided. Is more efficient.

  Further, as described above, the structural effect is the smallest when the driving angle Θ is 0, and the maximum structural effect is Θ = 90 ° in the tensile reinforcement 3a or Θ = −90 ° in the compression reinforcement 3b. It becomes.

  The calculation method of the reinforcement effect by such a reinforcing material 3 is demonstrated based on FIG.

In order to calculate the total reinforcement effect ΔP, first, the yield strength increase ΔPs due to the structural effect is calculated from the maximum axial force Nmax _i per reinforcement and the maximum shear force Smax _i per reinforcement.
ΔPs = Σ (Smax _i · cos Θ + Nmax _i · sin Θ) (1)
Calculated as Further, the sum is taken over all the reinforcing members 3 arranged on the basic body 2, i.e., i = 1 to n if there are n reinforcing members 3. Therefore, in the proof stress increment ΔPs due to the structural effect, the shear force S is maximized when the angle Θ is 0 °, and the axial force N is maximized when the angle Θ is 90 °.

Next, the yield strength increase ΔPr due to the reinforcing soil effect is calculated from the maximum axial force Nmax _i per reinforcing material and the maximum shearing force Smax _i per reinforcing material,
ΔPr = Σ (Nmax _i · cos Θ−Smax _i · sin Θ) · tan Φ · f (Θ) (2)
f (Θ) = [ ² cos ² (Θ−45 ° + Φ / 2) − (1-sinν)] / (1 + sinν) (3)
Calculate. Here, Θ is a placement angle of the reinforcing member 3 with respect to a reference line orthogonal to the horizontal force on the horizontal plane. Φ is the internal friction angle of the ground 4 where the foundation body 1 is built, and ν is the dilatancy angle of the ground (= Φ / 3). Further, the sum is taken over all the reinforcing members 3 arranged on the basic body 2, i.e., i = 1 to n if there are n reinforcing members 3.

The total reinforcement effect ΔP is obtained from the yield strength increase ΔPs due to this structural effect and the yield strength increase ΔPr due to the reinforcement soil effect.
ΔP = ΔPs + ΔPr (4)
Calculated as It has been confirmed by experiments using a series of models that the reinforcing effect is correctly calculated by such a calculation method.

  That is, from the viewpoint of the reinforcing effect, it is efficient to install at least the reinforcing material 3 at the above-described placement angle Θ at which the total reinforcing effect ΔP is substantially maximum based on the results of the expressions (1) to (4). It is.

  When the reinforcing material 3 cannot be disposed at the placement angle Θ that maximizes the total reinforcing effect ΔP due to the arrangement condition of the reinforcing material 3, either the strength increment ΔPs due to the structural effect or the strength increment ΔPr due to the reinforcing soil effect The reinforcing material 3 may be arranged at the placement angle Θ where the maximum is. Furthermore, by installing the reinforcing material on the base body 2 in parallel with the acting horizontal force, the structural effect of each reinforcing material 3 is maximized, and the reinforcing effect as a total of the reinforcing material 3 can be enhanced.

  According to the equations (1) and (2), as shown in FIG. 3, the effect of the reinforcing member 3 is almost parallel to the direction of the horizontal force (that is, the placement angle Θ is near 90 °). A structural effect that shares a part of the tensile stress can be expected on the mountain side, while a structural effect that shares a part of the compressive stress can be expected on the valley side. Furthermore, the reinforcing material 3 arranged with an angle in the direction of the horizontal force is expected to have a structural effect and a reinforced soil effect due to a part of the shear stress.

  When the foundation body 1 is built on an inclined land, the reinforcing material 3 may be installed only on the mountain side, and as shown in FIG. 2, a part of the reinforcing material 3, for example, the reinforcing material 3 located at the upper part. May be installed only on the mountain side.

  When a horizontal force and a bending moment are loaded from the mountain side to the valley side as external forces on the foundation body 2, the foundation body 2 rotates as shown in FIG. At this time, the reinforcing member 3c at the lower part of the mountain side of the foundation body 2 is subjected to a shearing force as shown in the figure, and the direction of this force is basically when a lifting load is applied to the ground-reinforced foundation. Will be the same. Therefore, a large shear resistance can be obtained by placing the reinforcing material 3 obliquely downward.

  On the other hand, a shearing force is applied to the reinforcing member 3d located at the upper part of the valley side in the opposite direction (downward) to the reinforcing member 3c of the lower part of the mountain side. Even in this case, a large shear resistance can be obtained by driving the reinforcing material 3d obliquely downward.

  Further, the reinforcing members 3c and 3d suppress the rotation of the foundation, and a great reinforcing effect can be obtained against the falling of the foundation. In addition, the reinforcing member 3c increases the force that restrains the slip surface of the soil block downward with respect to the wedge-shaped slip soil mass that may occur on the valley side of the foundation. Resistance can be increased.

  As described above, according to the present invention, the reinforcing member 3 installed in the foundation body 1 on which the horizontal force acts is arranged in a direction including at least the direction in which the proof stress increment ΔP is maximized. The reinforcing material 3 can be placed at the maximum value that combines the reinforced soil effect and the structural effect, and the foundation 1 can be efficiently reinforced, the cost of foundation work can be greatly reduced, and the construction period can be shortened. As the foundation body 1 becomes smaller, it is possible to reduce the remaining soil from the excavation work.

  Further, by arranging each reinforcing member in parallel with the direction of the horizontal force, the structural effect of each reinforcing member can be maximized and the reinforcing effect can be enhanced efficiently.

  Further, when the reinforcing material is disposed at least at an angle Θ where the maximum value of the proof stress increment ΔPr occurs, that is, when the horizontal force acts as a tensile force on the reinforcing material, the reinforcing material is disposed at least in the minimum principal strain direction. In the case where the reinforcing material acts as a compressive force, the reinforcing effect can be enhanced because the reinforcing material is disposed at least in the maximum principal strain direction.

  In addition, since the reinforcing material is arranged at a ratio of approximately 1 to 2 square meters on the outer peripheral surface of the basic body, the reinforcing effect on the number of reinforcing materials can be enhanced.

  Further, when the foundation body 2 is constructed, a mortar is placed between the excavation surface and the liner plate that supports the excavation surface, and the mortar completely fills the space between the excavation surface and the liner plate. I cannot guarantee it. However, in the present invention, since the plurality of reinforcing members 3 fixed in the natural ground 4 are fixed to the base body 2 through the liner plate, even if an external force due to an earthquake or the like is applied to the base body 1, The reinforcing material 3 does not escape from the natural ground 4. For this reason, as a result, the reinforcing material 3 is fixed in the ground, so that a frictional force can be reliably generated between the liner plate and the excavation surface.

  FIG. 10 shows the shape of the base body 1 as the second embodiment, which is characterized in that the horizontal cross-sectional shape of the base body 2 that was columnar in the first embodiment is elliptical. When the cross-sectional shape of the pier fixed on the foundation body 1 is a rectangle as shown by the dotted line in the figure, the size of the foundation body 1 is defined by the shortest distance from the outer circumference of the pier to the outer circumference of the foundation body 1. The base body 1 can be reduced in size by making it elliptical with respect to the case where the base body 1 is cylindrical. The horizontal cross-sectional shape of the basic body 2 is not limited to an elliptical shape, and may be an oval shape.

  FIG. 11 and FIG. 12 show the shape of the foundation body 1 as the third embodiment, which is characterized in that the foundation body 2 is configured in a bottomed cylindrical shape. In this embodiment, the remaining soil generated when the foundation body 2 is built in the internal space of the foundation body 2 with the bottom portion disposed below can be easily treated. After filling the internal space with the remaining soil, the upper opening of the foundation main body 2 is closed, and a pier or the like is built thereon. In this embodiment, the cylindrical basic body is used. However, the cross-sectional shape is not circular, and these may be hollow as an oval or oval shape as described above.

  The arrangement method of the reinforcing material in the foundation formation of the ground reinforcement type of the present invention is useful for downsizing the foundation body on which the piers and the like are built.

The vertical sectional view of the embodiment of the present invention. Sectional drawing of the cross section AA of FIG. The conceptual diagram explaining the reinforcement effect of the reinforcing material of this invention. An example of mesh for simulation calculation. The figure which shows the relationship between a reinforcement material number and a reinforcement effect. The figure which shows the reinforcement effect of a tensile reinforcement material. The figure which shows the reinforcement effect of a compression reinforcement material. The figure which shows other embodiment of a basic body. The figure which shows the other placement method of a reinforcing material. The figure which shows the other placement method of a reinforcing material. The front view which shows other embodiment of a foundation. FIG. The vertical sectional view of the conventional basic body. Similarly horizontal sectional view. Sectional drawing of the basic body explaining the support structure of the basic body with respect to extraction force similarly. Sectional drawing of the base body explaining the support structure of the base body with respect to a horizontal force similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foundation body 2 Foundation body 3 Reinforcement material 3a Tensile reinforcement material 3b Compression reinforcement material 4 Ground

Claims (8)

Drill a hole from the excavated surface of the foundation into the ground, fix a rigid reinforcing material in the ground and fix the base end of the reinforcing material in the foundation body to build the foundation. In the ground reinforcement type foundation forming method,
The reinforcing member is driven from the base body toward the outside in the horizontal direction,
It is calculated by the following equation (1), which increases the resistance of the natural ground to the horizontal force acting on the foundation by structurally sharing a part of the tensile stress, compressive stress and shear stress with respect to the natural ground. Proof strength increment ΔPs,
ΔPs = Σ (Smax _i · cos Θ + Nmax _i · sin Θ) (1)
Where Smax _i is the maximum shear force of the reinforcing material,
Nmax _i is the maximum axial force of the reinforcing material,
Θ is the angle formed by the horizontal line perpendicular to the direction of the horizontal force and the direction in which the reinforcing material is placed
Every time,
i corresponds to the number of reinforcing materials (i ≧ 1)
Strength which is calculated by the following formula (2) and formula (3), which increases the resistance of the ground to the horizontal force acting on the foundation by restraining the tensile strain and compression strain generated in the ground by the reinforcing material. Increment ΔPr,
ΔPr = Σ (Nmax _i · cos Θ−Smax _i · sin Θ) · tan Φ · f (Θ) (2)
f (Θ) = [ ² cos ² (Θ−45 ° + Φ / 2) − (1-sinν)] / (1 + sinν) (3)
Where Φ is the internal friction angle of the natural ground on which the foundation is built,
ν is the arrangement of the reinforcing material for reinforcing the horizontal bearing force in the foundation formation of the ground reinforcing type, wherein the reinforcing material is arranged when it is assumed that a horizontal force acts on the foundation body based on the dilatancy angle. Method.   2. The horizontal supporting force strengthening type in the foundation formation of the ground reinforcing type according to claim 1, wherein the reinforcing material is disposed at the angle Θ in which a maximum value obtained by adding at least the yield strength increments ΔPs and ΔPr is generated. Reinforcing material placement method.   2. The horizontal in the foundation formation of the ground reinforcement type according to claim 1, wherein the reinforcing material is disposed at least in the direction of the minimum principal strain when the horizontal force acts as a tensile force on the reinforcing material. Arrangement method of reinforcing capacity reinforcement.   The ground according to any one of claims 1 to 3, wherein the reinforcing material is disposed at least in a maximum principal strain direction when the horizontal force acts as a compressive force on the reinforcing material. Arrangement method of reinforcing material for strengthening horizontal bearing capacity in reinforced foundation formation.   The horizontal supporting force in the foundation formation of the ground reinforcement type according to any one of claims 1 to 4, wherein the reinforcing material is disposed on the outer peripheral surface of the foundation main body at a ratio of approximately one per 2 square meters. Arrangement method of reinforced reinforcement. The basic body built by excavating the natural ground,
A rod-shaped reinforcing material that is placed in the horizontal direction from the foundation body and is fixed in the natural ground;
In the ground-reinforced foundation with horizontal force acting,
When the horizontal force acts as a tensile force on the reinforcing material, arrange at least one of the reinforcing materials so as to coincide with the minimum principal strain direction of the natural ground,
In addition, when the horizontal force acts as a compressive force on the reinforcing material, at least one of the reinforcing materials is arranged so as to coincide with the maximum principal strain direction of the natural ground. A ground-reinforced foundation. The basic body built by excavating the natural ground,
A rod-shaped reinforcing material that is placed outside from the foundation body and is fixed in the natural ground;
In the ground-reinforced foundation with horizontal force acting,
The foundation body rotates around the center of rotation in the foundation body by horizontal force,
When the horizontal force acts as a compressive force on the reinforcing material, the reinforcing material is disposed obliquely downward from the foundation body, and the reinforcing material is aligned with the maximum principal strain direction of the natural ground. Arranging at least one of the reinforcing members,
When the horizontal force acts as a tensile force on the reinforcing material, the reinforcing material is arranged in the horizontal direction from the foundation body, and at least one of the reinforcing materials is aligned with the minimum principal strain direction of the natural ground. A ground-reinforced foundation that features books.   The ground reinforcing-type foundation body according to claim 6 or 7, wherein a horizontal sectional shape of the foundation body is any one of a circular shape, an elliptical shape, an oval shape, or an annular sectional shape thereof.

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