JP2010106545A - Method of constructing foundation structure in structure, and foundation structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of constructing foundation in a structure, capable of increasing coupling force between a foundation member constructed on a pile body and the pile body, capable of enhancing construction performance of the pile body, capable of reducing a construction cost by reducing a diameter of the pile body, capable of enhancing quality of the pile body, by using no stabilization liquid, and capable of enhancing earthquake resistance, horizontal resistance and the like by pseudo-increase of the diameter of the pile body, and by a lattice-like improved ground, and the foundation structure. <P>SOLUTION: A wall-like improved ground 2 is constructed lattice-likely within a soft ground 1, and then the pile body 6 is constructed integrally with the improved ground 2 in a crossed part of the lattice-like improved ground 2, by an earth drill construction method as a cast-in-place pile construction method. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a construction method of a foundation structure in a structure and a foundation structure, in particular, a wall-like improved ground is constructed in a lattice shape in a soft ground, and a pile body is formed by a cast-in-place pile method at the intersection of the lattice-like improved ground By integrating the ground with the improved ground, it is possible to increase the coupling force between the foundation member built on the pile body and the pile body, and also improve the workability of the pile body and reduce the pile body diameter. A structure that can reduce construction costs by improving the quality of the pile body by not using a stabilizing liquid, and can improve the earthquake resistance and horizontal resistance of the pile body by increasing the diameter of the pile body and improving the lattice shape. The construction method of the foundation structure in and the foundation structure constructed | assembled by this construction method.

  Conventionally, when piles are used as the foundation structure, even if the vertical resistance, bending resistance, and horizontal resistance of the piles are sufficient, the footing as a foundation member built on the piles and the bonding force between the underground beam and the piles There was a fear that it was insufficient and could not withstand an excessive shear force. Moreover, in order to integrate and resist adjacent piles, it was necessary to construct a rigid foundation member.

  These problems can be solved by increasing the pile diameter. That is, if the pile diameter is increased, the coupling force between the foundation member and the pile becomes sufficient, and the foundation member does not need to be significantly rigid.

  However, increasing the pile diameter leads to a decrease in workability and a significant increase in work period and construction cost. Note that this problem appears more prominently when piles are constructed on soft ground.

  Therefore, the inventors of the present application can improve the coupling force between the pile body and the foundation member constructed on the pile body, without increasing the pile diameter, and even in soft ground, A structure that can improve the seismic resistance and horizontal resistance of the structure, and, if the structure is a viaduct, pier, or abutment, can improve the train running performance during an earthquake. In order to obtain the construction method of the foundation structure and the foundation structure constructed by this construction method, intensive study was repeated. As a result, if the pile foundation and the improved ground constructed of a wall-like improved ground are combined in a lattice shape, the construction method of the foundation structure in the structure having the above characteristics and the foundation structure constructed by this construction method will be obtained. The knowledge that it can be obtained was acquired.

  The present invention has been made based on the above knowledge, and a wall-like improved ground is constructed in a grid in the ground, and a pile body is integrated with the improved ground by a cast-in-place pile method at the intersection of the grid-like improved ground. By constructing the pile body, it is possible to increase the coupling force between the foundation member built on the pile body and the pile body, and to improve the workability of the pile body and to reduce the construction cost by reducing the pile body diameter. Construction of foundation structure in the structure that can improve the quality of pile body by reducing, non-use of stabilizing liquid, and improving the earthquake resistance, horizontal resistance, etc. by pseudo increase of pile body diameter and lattice improved ground The object is to provide a method and a foundation structure constructed by this construction method.

  The present invention is characterized by the following.

  According to the first aspect of the present invention, a wall-like improved ground is constructed in a lattice pattern in the ground, and then a pile body is constructed integrally with the improved ground by a cast-in-place pile method at the intersection of the improved ground. It has the characteristics.

  The invention according to claim 2 is characterized in that, in the construction method of the foundation structure in the structure according to claim 1, the improved ground is constructed so that the depth of the improved ground is not the same. It is.

  The invention according to claim 3 is the construction method of the foundation structure in the structure according to claim 1 or 2, characterized in that a foundation member is constructed integrally with the improved ground on the improved ground. It is what you have.

  The invention according to claim 4 is the construction method of the foundation structure in the structure according to any one of claims 1 to 3, wherein the improved ground is constructed to a depth for constructing the pile body. It is what has.

  The invention according to claim 5 is characterized in that in the construction method of the foundation structure in the structure according to any one of claims 1 to 3, the improved ground is constructed only in the soft ground layer. It is.

  Invention of Claim 6 is the construction method of the foundation structure in a structure as described in any one of Claim 1 to 5, The diameter dimension of the said pile main body is the same in the longitudinal direction of the said pile main body. It has the characteristics to do.

  The invention according to claim 7 is the construction method of the foundation structure in the structure according to any one of claims 1 to 5, wherein the diameter dimension of the pile body is partially set in the longitudinal direction of the pile body. It is characterized by making it different.

  The invention according to claim 8 is the construction method of the foundation structure in the structure according to any one of claims 1 to 7, wherein a reinforcing bar is constructed in the intersecting portion of the improved ground, and thereafter It is characterized in that the pile body is constructed inside the reinforcing bar.

  The invention according to claim 9 is a wall-like improved ground constructed in a lattice shape in the ground, and a pile main body constructed integrally with the improved ground by a cast-in-place pile method at an intersection of the improved ground. It is characterized by comprising.

  The invention described in claim 10 is characterized in that, in the foundation structure in the structure described in claim 9, the improved ground is constructed so that the depth thereof is not the same.

  The invention according to claim 11 is characterized in that, in the foundation structure in the structure according to claim 9 or 10, a foundation member is constructed integrally with the improved ground on the improved ground. It is.

  The invention described in claim 12 is the foundation structure in the structure according to any one of claims 9 to 11, wherein the improved ground is constructed to a depth for constructing the pile body. It is what has.

  The invention described in claim 13 is characterized in that, in the foundation structure in the structure according to any one of claims 9 to 11, the improved ground is constructed only in a soft ground layer. It is.

  The invention described in claim 14 is the foundation structure in the structure according to any one of claims 9 to 13, wherein the diameter dimension of the pile body is the same in the longitudinal direction of the pile body. It has characteristics.

  The invention according to claim 15 is the foundation structure in the structure according to any one of claims 9 to 13, wherein a diameter dimension of the pile body is partially different in a longitudinal direction of the pile body. It has a feature in being.

  The invention according to claim 16 is the foundation structure in the structure according to any one of claims 9 to 15, wherein a reinforcing bar is constructed in the intersection of the improved ground, and inside the reinforcing bar It is characterized in that the pile body is constructed.

  According to this invention, the wall-like improved ground is constructed in a grid pattern in the ground, and the pile body is constructed integrally with the improved ground by the cast-in-place pile method at the intersection of the grid-like improved ground, It is possible to increase the bonding force between the foundation member built on the main body and the pile main body, and also improve the workability of the pile main body, reduce the construction cost by reducing the pile main body diameter, and avoid the use of a stabilizing liquid It is possible to improve the quality of the pile body, increase the pile body diameter in a pseudo manner, and improve the earthquake resistance, horizontal resistance, etc. by the grid-like improved ground.

  One embodiment of the construction method of the foundation structure in the structure of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a ground improvement process by a construction method of a foundation structure in a structure, (a) is a schematic plan view, (b) is a cross-sectional view along line AA in (a), (c) ) Is a cross-sectional view taken along line AA in FIG. 2A and 2B are diagrams showing an excavation process according to the construction method of a foundation structure in a structure according to the present invention, in which FIG. 2A is a schematic plan view, and FIG. 2B is a cross-sectional view taken along line AA in FIG. It is. FIG. 3 is a diagram showing a foundation structure in a structure constructed by the construction method of the foundation structure in the structure according to the present invention, wherein (a) is a schematic plan view, and (b) is a diagram (a). It is an AA sectional view taken on the line.

  In the construction method of the foundation structure in the structure of the present invention, first, as shown in FIG. In order to construct the wall-like improved ground 2 in a lattice shape, for example, it is constructed by a trencher type ground improving device. A trencher type ground improvement device will be briefly described with reference to the drawings.

  FIG. 9 is a partial cross-sectional view showing a state where the ground improvement is performed by the trencher type ground improvement device, and FIG. 10 is a plan view showing a drive chain of the trencher type ground improvement device.

  The trencher type ground improvement device supports a stirring and mixing device 9 called a trencher type at the tip of an arm 8 of a heavy construction machine 7 such as a backhoe, and between the driving wheel 10 and the driven wheel 11 of the stirring and mixing device 9. In addition, the drive chain 13 provided with the stirring blade 12 on the outer periphery is wound, and the drive chain 13 is driven around in the ground, whereby the stirring ground 12 is stirred and mixed while excavating the soft ground 1. The stirring and mixing device 9 includes a discharging means such as cement-based solidified material, and in parallel with the excavation and stirring and mixing, the solidified material is introduced into the soft ground 1 which has been stirred and mixed to improve the ground. It is like that.

  According to the trencher type ground improvement device, as shown in FIG. 1, the wall-like improved ground 2 can be constructed on the soft ground 1 in a lattice shape. In this example, the grid-like improved ground 2 has one grid, but it is of course possible to construct the grid so that there are two or more grids. The pile main body mentioned later is constructed in each crossing part of the shape improvement ground 2.

  In this way, when the improved ground 2 is constructed in the grid shape on the soft ground 1, as shown in FIG. 2, the excavation holes 3 are formed at the intersections of the grid-shaped improved ground 2, and thereafter, in FIG. As shown, a pile body 6 made of concrete 5 reinforced by a reinforcing bar 4 is constructed integrally with the improved ground 2 in the excavation hole 3. The pile body 6 is constructed by, for example, an earth drill method that is a cast-in-place pile method.

  Hereinafter, the earth drill method implemented in the present invention will be described with reference to the drawings.

  The ground drill method has the advantages of low vibration, low noise, simple equipment, fast construction speed, economics, and the ability to construct even in a small site. As will be described later, since it is not necessary to use a stabilizing liquid, there is an advantage that there is no fear of deterioration in the quality of the pile body due to the mixing of the stabilizing liquid into the cast concrete.

  FIG. 4 is a diagram showing a process for constructing a cast-in-place pile on the improved ground by the earth drill method implemented in the present invention, and (a) shows the rotating shaft of the excavator on the intersection of the grid-shaped improved ground. A schematic cross-sectional view showing the positioned state, (b) is a schematic cross-sectional view showing a state in which the improved ground is being excavated by the excavating blade attached to the rotary shaft of the excavator, and (c) is an excavation hole formed. (D) is a schematic cross-sectional view showing a state in which a reinforcing bar is inserted into the excavation hole, and (e) is a concrete placement in the excavation hole in which the reinforcing bar is inserted. It is a schematic sectional drawing which shows a state.

  First, as shown in FIG. 4A, positioning is performed so that the rotary shaft (Kelly bar) 14 of the excavator (not shown) comes on the intersection of the grid-like improved ground 2. Next, as shown in FIG. 4B, the excavating blade 15 is attached to the tip of the rotary shaft 14, and the excavating blade 15 is rotated to excavate the intersection of the improved ground 2. At this time, since the improved ground 2 is excavated, there is no collapse of the excavation hole wall and it is not necessary to use a stabilizing liquid. As a result, there is no fear of the quality of the pile body due to the mixing of the stabilizing liquid into the cast concrete. The excavation depth by the excavation blade 15 is within the construction depth range of the improved ground 2.

  When the excavation holes 3 are formed at the intersections of the grid-like improved ground 2 as shown in FIG. 4 (c) in this manner, as shown in FIG. 4 is suspended and inserted into the excavation hole 3 by the crane 16. And as shown in FIG.4 (e), if concrete 5 is laid in the excavation hole 3 in which the reinforcing bar 4 was inserted, and the concrete 5 is solidified, it will be in the cross | intersection part of the grid | lattice-like improved ground 2 As shown in FIG. 3, the columnar pile body 6 is constructed integrally with the improved ground 2.

  The improved ground 2 may be constructed over the entire pile body 6 as in the above example, but as shown in FIG. 5, it may be constructed only in the soft ground layer, thereby reducing the construction cost. Can be reduced. In addition, the relationship between the ground depth and the ground strength is shown on the left side in FIG. The ground strength is higher as it goes to the right in the figure.

  Although the diameter dimension of the pile main body 6 may be the same in the longitudinal direction of the pile main body 6 as in the above example, the diameter of the excavation hole 3 formed in the improved ground 2 as shown in FIG. If the diameter of the pile body 6 is partially varied in the longitudinal direction of the pile body 6, the pile body 6 is constructed more integrally with the improved ground 2. The In order to make the diameter of the excavation hole 3 partially different in the longitudinal direction of the excavation hole 3, excavation blades 15 having different diameters may be used.

  As in the above example, the grid-like improved ground 2 may be constructed so that the depth is the same, but may be constructed so that the depth is not the same. That is, as shown in FIG. 7, it may be constructed so that the periphery is deep and the central part is shallow, thereby improving the ground resistance.

  As shown in FIG. 8, if the anchor rebar 17 with a hook is embedded in the improved ground 2 and integrated with a foundation member 18 such as a viaduct underground beam or a footing of a bridge, the coupling force between the improved ground 2 and the foundation member 18 is obtained. Increases significantly.

  Further, as shown in FIG. 1 (c), if a cylindrical reinforcing bar 19 is constructed in the intersection of the improved ground 2 and a drilling hole 3 is formed inside the reinforcing bar 19, excavation at the time of construction of the pile body 4 is performed. The collapse of the wall of the hole 3 can be reliably prevented. The reinforcing bar 19 may be constructed over the entire length of the improved ground 2 if possible, but may be only the upper layer as shown. Moreover, if the upper part of the reinforcing bar 19 is protruded from the excavation hole 3 and the structure or footing constructed on the pile body 4 is integrated with the upper part of the reinforcing bar 19, smooth stress transmission can be achieved. In order to construct the reinforcing bar 19 in the improved ground 2, the reinforcing bar 19 may be dropped into the improved ground 2 by a vibration method using a vibrator when the improved ground 2 is not hardened.

  As described above, according to the present invention, the wall-like improved ground 2 is constructed in the soft ground 1 in a lattice shape, and the pile body 6 is attached to each intersection of the lattice-like improved ground 2 by the cast-in-place pile method. The following effects are brought about by constructing integrally with the improved ground 2.

(1) It is possible to increase the bonding force between the pile body 6 and the foundation member 18 such as an underground beam or footing constructed on the pile body 6.
(2) Since there is no fear of collapse of the excavation hole 3, the workability of the pile body 6 is greatly improved.
(3) When the borehole wall is pressed by the surrounding ground, there is no fear that the diameter of the borehole 3 is reduced and the design pile diameter is not satisfied.
(4) Since there is no need to use a stabilizing liquid, there is no fear that the stabilizing liquid is mixed into the concrete and the quality of the pile body 6 is deteriorated.
(5) Since the pile main body 6 is reinforced by the improved ground 2, the diameter of the pile main body 6 can be reduced, and as a result, the construction cost is reduced.
(6) The diameter of the pile main body 6 is increased in a pseudo manner by the improved ground 2 and, in addition, the improved ground can be constructed in a lattice shape, so that the earthquake resistance, the horizontal resistance, and the like can be significantly improved.

It is a figure which shows the ground improvement process by the construction method of the foundation structure in a structure of this invention, (a) is a schematic plan view, (b) is the sectional view on the AA line of (a) figure, (c) ) Is a cross-sectional view taken along line AA of FIG. It is a figure which shows the excavation process by the construction method of the foundation structure in a structure of this invention, (a) is a schematic plan view, (b) is the sectional view on the AA line of (a) figure. It is a figure which shows the foundation structure in a structure constructed | assembled by the construction method of the foundation structure in a structure of this invention, (a) is a schematic plan view, (b) is AA of a figure (a). It is line sectional drawing. It is a figure which shows the construction process of the cast-in-place pile to the improved ground by the earth drill method implemented by this invention, (a) is the state which positioned the rotating shaft of the excavator on the cross | intersection part of a grid-like improved ground The schematic cross-sectional view shown, (b) is a schematic cross-sectional view showing a state where the improved ground is excavated by the excavating blade attached to the rotating shaft of the excavator, (c) is the improved ground where the excavation hole is formed (D) is a schematic cross-sectional view showing a state in which a reinforcing bar is inserted into the excavation hole, and (e) is a method for placing a pile body by placing concrete in the excavation hole in which the reinforcing bar is inserted. It is a schematic sectional drawing which shows the constructed state. It is a schematic sectional drawing which shows the state which constructed | assembled the improved ground only in the soft ground layer and formed the excavation hole. It is a schematic sectional drawing which shows the state which made the diameter of the excavation hole formed in improved ground partially differ in the longitudinal direction of an excavation hole. It is a schematic sectional drawing which shows the improved ground constructed | assembled so that depth may differ. It is a schematic sectional drawing which shows the state which fixed the footing as a base member on the improved ground. It is a fragmentary sectional view showing the state where the ground improvement is performed by the trencher type ground improvement device. It is a top view which shows the drive chain of a trencher type ground improvement apparatus.

Explanation of symbols

1: Soft ground 2: Improved ground 3: Drilling hole 4: Reinforcing bar 5: Concrete 6: Pile body 7: Heavy construction equipment 8: Arm 9: Stirring mixing device 10: Drive wheel 11: Driven wheel 12: Stirring blade 13: Drive Chain 14: Rotating shaft
15: Excavation blade 16: Crane 17: Anchor rebar 18: Foundation member 19: Rebar rod

Claims (16)

  A foundation in a structure characterized in that a wall-like improved ground is constructed in a lattice pattern in the ground, and then a pile body is constructed integrally with the improved ground by a cast-in-place pile method at the intersection of the improved ground Construction method of structure.   The construction method of a foundation structure in a structure according to claim 1, wherein the improved ground is constructed so that the depth of the improved ground is not the same.   The construction method for a foundation structure in a structure according to claim 1 or 2, wherein a foundation member is constructed integrally with the improvement ground on the improvement ground.   The construction method of a foundation structure in a structure according to any one of claims 1 to 3, wherein the improved ground is constructed to a depth at which the pile main body is constructed.   The construction method of a foundation structure in a structure according to any one of claims 1 to 3, wherein the improved ground is constructed only in a soft ground layer.   The construction method of a foundation structure in a structure according to any one of claims 1 to 5, wherein the diameter of the pile body is the same in the longitudinal direction of the pile body.   The construction method for a foundation structure in a structure according to any one of claims 1 to 5, wherein a diameter dimension of the pile body is partially varied in a longitudinal direction of the pile body.   The structure according to any one of claims 1 to 7, characterized in that a reinforcing bar is built in the intersection of the improved ground, and thereafter the pile body is built inside the reinforcing bar. Construction method of the foundation structure in the object.   A structure characterized by comprising a wall-like improved ground constructed in a lattice shape in the ground, and a pile body constructed integrally with the improved ground by a cast-in-place pile method at the intersection of the improved ground The basic structure of things.   The foundation structure in the structure according to claim 9, wherein the improved ground is constructed so that the depths thereof are not the same.   The foundation structure in a structure according to claim 9 or 10, wherein a foundation member is constructed integrally with the improved ground on the improved ground.   The foundation structure in a structure according to any one of claims 9 to 11, wherein the improved ground is constructed to a depth for constructing the pile main body.   The foundation structure in a structure according to any one of claims 9 to 11, wherein the improved ground is constructed only in a soft ground layer.   The foundation structure in a structure according to any one of claims 9 to 13, wherein the pile body has the same diameter in the longitudinal direction of the pile body.   The foundation structure in a structure according to any one of claims 9 to 13, wherein a diameter dimension of the pile body is partially different in a longitudinal direction of the pile body.   The structure according to any one of claims 9 to 15, wherein a reinforcing bar is built in the intersection of the improved ground, and the pile main body is built inside the reinforcing bar. Foundation structure.

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