JP2007247339A - Newly constructed foundation structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive newly constructed foundation structure by which the rigidity of the ground around footing construction is enhanced to improve a supporting force of a footing. <P>SOLUTION: An annular underground wall 13 is buried in the ground 11 around a place where the footing is constructed. The footing 15 is constructed on heads 14b of a plurality of piles 14 driven into the annular underground wall 13 so that front ends 14a may reach a predetermined position 12. In the newly constructed foundation structure 10 which is thus constructed, the underground wall 13 is buried to a depth in a range effective for the horizontal resistance of the plurality of piles 14, and the ground 11 in the underground wall 13 is solidified and improved to the depth in the range effective for the horizontal resistance of the plurality of piles 14. The solidified and improved part is shown by a symbol A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a new foundation structure in which a new footing is constructed on a plurality of new piles.

  As this kind of new foundation structure, there is one shown in FIG. 17 (see, for example, Patent Document 1).

As shown in FIG. 17, the pile foundation 1 as a new foundation structure has a rectangular tubular reinforced concrete sheet pile 3 embedded around a footing construction planned position of the ground 2, and the rectangular tubular reinforced concrete sheet pile 3 is embedded in the square foundation. A footing 5 is constructed on the heads 4a of the piles 4 that have been driven. After the footing 5 is constructed, a reinforced concrete sheet pile 3 is left in the ground 2.
JP 2000-129696 A JP 2000-80663 A

  However, since the conventional pile foundation 1 has a structure in which a plurality of piles 4 are simply placed in the ground 2 in the rectangular tubular reinforced concrete sheet pile 3, a pile 4 having a large diameter or a large number is used. Otherwise, the horizontal resistance of the pile 4 (horizontal passive resistance) was lowered, and the support capacity of the pile foundation was not sufficiently obtained. Further, since the reinforced concrete sheet pile 3 has to be buried deep into the ground 2, the cost is increased accordingly.

  Therefore, the present invention has been made to solve the above-described problems, and provides an inexpensive new foundation structure capable of increasing the strength of the foundation structure by increasing the rigidity of the ground around the footing construction and the pile. The purpose is to do.

  In the first aspect of the present invention, an annular underground wall is embedded around the planned footing construction position of the ground, and footings are applied to the heads of a plurality of piles whose tips are driven into a predetermined position in the annular underground wall. In the newly constructed foundation structure constructed, the annular underground wall is buried to a depth within a range effective for the horizontal resistance of the plurality of piles, and the ground in the annular underground wall is horizontally embedded in the plurality of piles. It is characterized by solidifying and improving to a depth within the range effective for resistance.

  The invention of claim 2 embeds an annular underground wall around the planned footing construction position of the ground, and applies footings to the heads of a plurality of piles whose tips are driven to a predetermined position in the annular underground wall. In the newly constructed foundation structure constructed, the annular underground wall is buried to a depth within a range effective for the horizontal resistance of the plurality of piles, and the ground in the annular underground wall is horizontally embedded in the plurality of piles. It is characterized by solidifying and improving to a depth effective for resistance, and further solidifying and improving a filling portion between the inner surface of the annular underground wall and the solidifying improved portion.

  In the invention of claim 3, an annular underground wall is embedded around the planned footing construction position of the ground, and footings are applied to the heads of a plurality of piles whose tips are driven into a predetermined position in the annular underground wall. In the new foundation structure constructed, the annular underground wall is buried to a depth that is effective for the horizontal resistance of the plurality of piles, and the inner and outer grounds of the annular underground wall are embedded in the plurality of grounds. It is characterized by solidification and improvement to a depth that is effective for the horizontal resistance of piles.

  As described above, according to the first aspect of the present invention, the annular underground wall embedded in the ground around the footing construction is embedded to a depth within a range effective for the horizontal resistance of a plurality of piles, and the annular By solidifying and improving the ground in the underground wall to a depth that is effective for the horizontal resistance of multiple piles, the rigidity of the ground around the footing construction and the piles is further increased, and the yield strength of the entire foundation structure is further increased. Can be increased.

  According to the invention of claim 2, the annular underground wall embedded in the ground around the footing construction is embedded to a depth effective in the horizontal resistance of the plurality of piles, and the ground in the annular underground wall is embedded. And the piles around the footing construction and piles by solidifying and improving to the depth effective for the horizontal resistance of multiple piles, and further solidifying and improving the padding between the inner surface of the annular underground wall and the solidified improvement portion It is possible to further increase the strength of the foundation structure as a whole by further increasing the rigidity of the ground around the foundation.

  According to the invention of claim 3, the annular underground wall embedded in the ground around the footing construction is embedded to a depth effective for the horizontal resistance of the plurality of piles, and the inside of the annular underground wall is By solidifying and improving the outer ground to a depth that is effective for the horizontal resistance of multiple piles, it is possible to further increase the rigidity of the ground around the footing construction and around the piles, and further increase the yield strength of the entire foundation structure. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a new foundation structure according to a first embodiment of the present invention, and FIG. 2 (a) is a cross-sectional view showing a state in which a ground wall is embedded in the ground and the ground in the ground wall is improved. FIG. 2 (b) is a cross-sectional view showing a state in which the ground and the ground improved portion in the ground wall are drilled, and FIG. 3 shows a state in which a new pile is placed in the ground improved portion. FIG. 4 is a cross-sectional view showing a state where the ground within the ground wall is excavated, and FIG. 5 is a cross-sectional view showing a state where a new footing is constructed on the head of the new pile.

  As shown in FIG. 1 and FIG. 5, the new foundation structure 10 includes a square tubular steel sheet pile wall (annular underground wall) 13 embedded around the planned footing construction position of the ground 11, and this rectangular tubular shape. In the steel sheet pile wall 13, a plurality of piles 14 whose tips 14 a are driven to the support layer (predetermined position) 12 and footings (foundations) 15 constructed on the heads 14 b of the plurality of piles 14 are provided. Yes.

  In the ground 11 around the footing construction, a square tubular steel sheet pile wall 13 is embedded to a depth (for example, 1 / β to π / 2β) effective for the horizontal resistance of the plurality of piles 14. Further, the entire area (all) of the ground 11 in the square cylindrical steel sheet pile wall 13 is ground improved (solidified) by a mechanical / jet stirring method to a depth effective for the horizontal resistance of the plurality of piles 14. This solidification improvement portion is indicated by the symbol A.

  The range effective for the horizontal resistance of the plurality of piles 14 is, for example, the characteristic length of the reciprocal (1 / β) of the characteristic value (β) in the case of a semi-infinite length pile (Chang's method).

  Further, the outer peripheral surface 15a of the reinforced concrete footing 15 is constructed on the inner peripheral surface (inner surface) 13a of the square cylindrical steel sheet pile wall 13 without gaps, and is integrated and fixed to the square cylindrical steel sheet pile wall 13. Has been.

  Next, the construction procedure of the new foundation structure 10 of the first embodiment will be described.

  First, as shown in FIG. 2A, a square cylindrical steel sheet pile wall 13 is placed on the ground 11 around the footing construction to a depth that is effective for the horizontal resistance of the plurality of piles 14. Then, the entire area of the ground 11 in the square cylindrical steel sheet pile wall 13 is solidified by injection and agitation and mixing of a solidified material such as cement milk by a mechanical / jet agitation method to a depth effective for the horizontal resistance of the plurality of piles 14. Improve. Next, as shown in FIG. 2 (b), a plurality of holes B for placing a plurality of piles 14 at predetermined positions of the ground 11 and the solidified portion A in the square cylindrical steel sheet pile wall 13 are formed. Drill holes.

  Next, as shown in FIG. 3, the cast-in-place concrete pile 14 is driven into each hole B of the solidification improved portion A until the tip 14 a reaches the support layer 12. When the pile 14 is a ready-made pile such as a concrete pile or a steel pipe pile, the pile 14 is driven until its tip 14a reaches the support layer 12. At this time, the solidified material C, such as cement milk, is filled in the gaps between the respective piles 14 and the respective holes B of the solidification improving portion A. Next, as shown in FIG. 4, the upper ground 11 in the square cylindrical steel sheet pile wall 13 is excavated.

  Next, as shown in FIG. 5, a reinforced concrete footing 15 is constructed on the top surface of the head 14 b of each pile 14 and the upper surface of the solidified portion A. At this time, the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 is used as a mold, and the outer peripheral surface 15a of the reinforced concrete footing 15 is formed on the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 without a gap. It is constructed and integrated with the square cylindrical steel sheet pile wall 13. Then, the upper portion of the square cylindrical steel sheet pile wall 13 protruding upward from the upper surface 15b of the reinforced concrete footing 15 is cut and removed, and the excavated ground 11 is buried on the upper surface 15b of the reinforced concrete footing 15. By returning, the new foundation structure 10 shown in FIG. 1 is completed.

  In this manner, the outer peripheral surface 15a of the footing 15 is attached to the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 embedded in the ground 11 around the footing construction to a depth within a range effective for the horizontal resistance of the plurality of piles 14. The footing 15 and the steel sheet pile wall 13 are integrated and fixed closely, and the ground 11 in the square cylindrical steel sheet pile wall 13 is improved to a depth effective for the horizontal resistance of the plurality of piles 14. Therefore, even if the number of piles 14 is reduced compared to the conventional pile foundation 1 shown in FIG. 17 or a small-diameter one is used, the overall rigidity (strength) of the new foundation structure 10 is more than that of the conventional one. It can be improved and the cost can be reduced accordingly.

  The square cylindrical steel sheet pile wall 13 and the reinforced concrete footing 15 are integrated and fixed, and the entire region of the ground 11 directly below the reinforced concrete footing 15 in the square cylindrical steel sheet pile wall 13 is provided with a plurality of piles. Since the solidification is improved to a depth effective for the horizontal resistance of 12, the strength of the reinforced concrete footing 15 and the solidification improvement portion A and the restraining effect of the square cylindrical steel sheet pile wall 13 cause the horizontal resistance (lateral Resistance) can be increased. Furthermore, the adhesion resistance increases by the solidification improvement of the surrounding ground of the heads 14b of the plurality of piles 14 in the square cylindrical steel sheet pile wall 13, and the vertical supporting force can be increased.

  In addition, the rigidity around the newly reinforced concrete footing 15 is further increased by the increase in internal pressure accompanying the ground improvement in the entire area of the steel sheet pile wall 13 in the shape of the rectangular tube. Furthermore, the rigidity of the square cylindrical steel sheet pile wall 13 has the effect of suppressing deformation around the footing 15 and the square cylindrical steel sheet pile wall 13 itself has deformation resistance (ring effect), so that it is level 2 class. The horizontal displacement and rotation of the footing 15 when the seismic load is applied can be suppressed, and the earthquake resistance can be improved. By these, the proof stress of the new foundation structure 10 can be improved.

  In addition, liquefaction of an intermediate | middle layer can be suppressed by putting the square cylindrical steel sheet pile wall 13 into non-liquefied layers, such as a clay layer.

  FIG. 6 is a cross-sectional view showing a new foundation structure according to a second embodiment of the present invention, and FIG. 7A is a cross-sectional view showing a state in which the ground wall is embedded in the ground and the ground in the ground wall is improved. 7 (b) is a sectional view showing a state in which the space between the ground wall and the ground improved portion is improved and the ground in the ground wall and the ground improved portion are drilled, and FIG. 8 is the ground surface. 9 is a cross-sectional view showing a state where a new pile has been placed in the drilled portion of the improvement, FIG. 9 is a cross-sectional view showing a state where the ground in the ground wall has been excavated, and FIG. 10 is newly installed on the head of the new pile It is sectional drawing which shows the state which constructed | assembled the footing.

  As shown in FIGS. 6 and 10, the new foundation structure 10 ′ includes a square cylindrical steel sheet pile wall (annular underground wall) 13 embedded around the footing construction planned position of the ground 11, and this square cylinder. A plurality of piles 14 whose leading ends 14a are driven to a support layer (predetermined position) 12 in a steel sheet pile wall 13 and a footing (foundation) 15 constructed on the heads 14b of the plurality of piles 14 are provided. ing.

  In the ground 11 around the footing construction, a square tubular steel sheet pile wall 13 is embedded to a depth (for example, 1 / β to π / 2β) effective for the horizontal resistance of the plurality of piles 14. Moreover, the ground improvement (solidification improvement) is carried out to the depth of the range effective in the horizontal resistance of the some pile 14 about the substantially whole area of the ground 11 in the square cylindrical steel sheet pile wall 13 by the mechanical stirring method. This solidification improvement portion is indicated by the symbol A. Further, the interstitial portion D between the steel sheet pile wall (inner surface) 13a of the square tubular underground wall and the solidification improving portion A is further solidified and improved by a jet stirring method.

  Further, the outer peripheral surface 15a of the reinforced concrete footing 15 is constructed on the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 without gaps, and is integrated and fixed to the square cylindrical steel sheet pile wall 13. .

  Next, the construction procedure of the new foundation structure 10 ′ of the second embodiment will be described.

  First, as shown in FIG. 7A, a square cylindrical steel sheet pile wall 13 is driven to a depth effective in the horizontal resistance of the piles 14 on the ground 11 around the footing construction. Then, almost the entire area of the ground 11 in the square cylindrical steel sheet pile wall 13 is solidified by injection and agitation mixing of a solidified material such as cement milk by a mechanical agitation method to a depth effective for the horizontal resistance of the plurality of piles 14. Improve. Next, as shown in FIG. 7 (b), after further solidifying and improving the interstitial portion D by a jet stirring method between the steel sheet pile wall 13a of the square tubular underground wall and the solidification improving portion A, A plurality of holes B for drilling a plurality of piles 14 at predetermined positions of the ground 11 and the solidified portion A in the square cylindrical steel sheet pile wall 13 are drilled.

  Next, as shown in FIG. 8, the cast-in-place concrete pile 14 is driven into each hole B of the solidification improved portion A until the tip 14 a reaches the support layer 12. When the pile 14 is a ready-made pile such as a concrete pile or a steel pipe pile, the pile 14 is driven until its tip 14a reaches the support layer 12. At this time, the solidified material C, such as cement milk, is filled in the gaps between the piles 14 and the holes B of the solidified portion A. Next, as shown in FIG. 9, the upper ground 11 in the square cylindrical steel sheet pile wall 13 is excavated.

  Next, as shown in FIG. 10, a reinforced concrete footing 15 is constructed on the top surface of the head 14 b of each pile 14 and the upper surface of the solidified portion A and the padding portion D. At this time, the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 is used as a mold, and the outer peripheral surface 15a of the reinforced concrete footing 15 is formed on the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 without a gap. It is constructed and integrated with the square cylindrical steel sheet pile wall 13. Then, the upper portion of the square cylindrical steel sheet pile wall 13 protruding upward from the upper surface 15b of the reinforced concrete footing 15 is cut and removed, and the excavated ground 11 is buried on the upper surface 15b of the reinforced concrete footing 15. By returning, the new foundation structure 10 'shown in FIG. 6 is completed.

  In this manner, the outer peripheral surface 15a of the footing 15 is attached to the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 embedded in the ground 11 around the footing construction to a depth within a range effective for the horizontal resistance of the plurality of piles 14. The footing 15 and the steel sheet pile wall 13 are integrated and fixed closely, and the ground 11 in the square cylindrical steel sheet pile wall 13 is improved to a depth effective for the horizontal resistance of the plurality of piles 14. Since the solidified portion D between the steel sheet pile wall 13a and the solidified improvement portion A of the square cylindrical underground wall is further solidified and improved, compared with the conventional pile foundation 1 shown in FIG. Therefore, the overall rigidity (strength) of the new foundation structure 10 'can be improved as compared with the conventional structure even if the number of the piles 14 is reduced or a small diameter is used, and the cost can be reduced accordingly. it can.

  In addition, the square cylindrical steel sheet pile wall 13 and the reinforced concrete footing 15 are integrated and fixed, and the entire region of the ground 11 directly below the reinforced concrete footing 15 in the square cylindrical steel sheet pile wall 13 is provided with a plurality of piles. Since the solidified portion of the square sheet-like wall 13a and the solidified portion A between the solidified portion A is further solidified and improved to a depth effective for the horizontal resistance of 12, the reinforced concrete The horizontal resistance (lateral resistance) of the plurality of piles 12 can be increased by the strength of the made footing 15, the solidification improving portion A and the filling portion D, and the restraining effect of the square cylindrical steel sheet pile wall 13. Furthermore, the adhesion resistance increases by the solidification improvement of the surrounding ground of the heads 14b of the plurality of piles 14 in the square cylindrical steel sheet pile wall 13, and the vertical supporting force can be increased.

  In addition, the rigidity around the newly reinforced concrete footing 15 is further increased by the increase in internal pressure accompanying the ground improvement in the entire area of the steel sheet pile wall 13 in the shape of the rectangular tube. Furthermore, the rigidity of the square cylindrical steel sheet pile wall 13 has the effect of suppressing deformation around the footing 15 and the square cylindrical steel sheet pile wall 13 itself has deformation resistance (ring effect), so that it is level 2 class. The horizontal displacement and rotation of the footing 15 when the seismic load is applied can be suppressed, and the earthquake resistance can be improved. By these, the proof stress of newly installed foundation structure 10 'can be improved.

  FIG. 11 is a cross-sectional view showing a newly-founded basic structure according to a third embodiment of the present invention, FIG. 12 (a) is a cross-sectional view showing a ground improved state, and FIG. 12 (b) is an underground view of the ground improved portion. 13 is a cross-sectional view showing a state where the wall is buried, FIG. 13 is a cross-sectional view showing a state where the ground and the ground improved portion in the ground wall are drilled, and FIG. 14 is a diagram showing a new pile in the ground improved portion of the ground improvement FIG. 15 is a cross-sectional view showing a state in which the ground in the ground wall is excavated, and FIG. 16 is a cross-sectional view showing a state in which a new footing is constructed on the head of the new pile. is there.

  As shown in FIGS. 11 and 16, the new foundation structure 10 ″ includes a square cylindrical steel sheet pile wall (annular underground wall) 13 embedded around the planned footing construction position of the ground 11, and this square cylinder. A plurality of piles 14 whose leading ends 14a are driven to a support layer (predetermined position) 12 in a steel sheet pile wall 13 and a footing (foundation) 15 constructed on the heads 14b of the plurality of piles 14 are provided. ing.

  In the ground 11 around the footing construction, a square tubular steel sheet pile wall 13 is embedded to a depth (for example, 1 / β to π / 2β) effective for the horizontal resistance of the plurality of piles 14. In addition, the entire area (all) of the inner and outer ground 11 of the rectangular steel sheet pile wall 13 is ground improved (solidified) to a depth that is effective for the horizontal resistance of the plurality of piles 14 by a mechanical / jet stirring method. It is. This solidification improvement portion is indicated by the symbol A.

  Further, the outer peripheral surface 15a of the reinforced concrete footing 15 is constructed on the inner peripheral surface (inner surface) 13a of the square cylindrical steel sheet pile wall 13 without gaps, and is integrated and fixed to the square cylindrical steel sheet pile wall 13. Has been.

  Next, the construction procedure of the newly installed foundation structure 10 ″ of the third embodiment will be described.

  First, as shown in FIG. 12 (a), a solidified material such as cement milk is ground by a mechanical stirring method using a retarder to a depth that is effective for the horizontal resistance of the piles 14 around the ground 11 around the footing construction. Improves solidification by pouring and stirring. Next, as shown in FIG. 12 (b), before the solidified improvement portion A of the ground 11 around the footing construction is solidified, a square cylindrical steel sheet pile wall 13 is placed in the solidified improvement portion A in a plurality of piles 14. To the depth of the effective range for horizontal resistance. Under the present circumstances, as shown in FIG.12 (b), the solidification improvement part A is located in the inner side and the outer side of the square cylindrical steel sheet pile wall 13. FIG. Then, as shown in FIG. 13, a plurality of holes B for drilling a plurality of piles 14 at predetermined positions of the ground 11 and the solidified portion A in the square cylindrical steel sheet pile wall 13 are drilled.

  Next, as shown in FIG. 14, a cast-in-place concrete pile 14 is driven into each hole B of the solidification improved portion A until its tip 14 a reaches the support layer 12. When the pile 14 is a ready-made pile such as a concrete pile or a steel pipe pile, the pile 14 is driven until its tip 14a reaches the support layer 12. At this time, the solidified material C, such as cement milk, is filled in the gaps between the respective piles 14 and the respective holes B of the solidification improving portion A. Next, as shown in FIG. 15, the upper ground 11 and the upper part of the solidification improving portion A in the square tubular steel sheet pile wall 13 are excavated.

  Next, as shown in FIG. 16, a reinforced concrete footing 15 is constructed on the top surface of the head 14 b of each pile 14 and the upper surface of the solidified portion A. At this time, the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 is used as a mold, and the outer peripheral surface 15a of the reinforced concrete footing 15 is formed on the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 without a gap. It is constructed and integrated with the square cylindrical steel sheet pile wall 13. Then, the upper portion of the square cylindrical steel sheet pile wall 13 protruding upward from the upper surface 15b of the reinforced concrete footing 15 is cut and removed, and the excavated ground 11 is buried on the upper surface 15b of the reinforced concrete footing 15. By returning, the new foundation structure 10 ″ shown in FIG. 11 is completed.

  In this way, the footing is performed on the inner peripheral surface 13a of the square cylindrical steel sheet pile wall 13 embedded in the solidified improvement portion A in the ground 11 around the footing construction to the depth effective for the horizontal resistance of the plurality of piles 14. 15, the footing 15 and the steel sheet pile wall 13 are integrated and fixed, and the ground 11 on the inner side and the outer side of the square cylindrical steel sheet pile wall 13 is connected to the horizontal resistance of the plurality of piles 14. Since the ground has been improved and solidified to an effective depth, the number of piles 14 is reduced compared to the conventional pile foundation 1 shown in FIG. The overall rigidity (strength) of 10 ″ can be improved and the cost can be reduced accordingly.

  In addition, the square cylindrical steel sheet pile wall 13 and the reinforced concrete footing 15 are integrally fixed, and the entire area directly below the reinforced concrete footing 15 inside the square cylindrical steel sheet pile wall 13 and the square cylindrical steel. Since the ground 11 outside the sheet pile wall 13 has been solidified and improved to a depth effective for the horizontal resistance of the plurality of piles 12, the strength of the reinforced concrete footing 15 and the solidification improved portion A and the steel sheet pile wall 13 of the rectangular cylindrical shape The horizontal resistance (lateral resistance) of the plurality of piles 12 can be increased by the restraining effect. Furthermore, adhesion resistance increases by the solidification improvement of the surrounding ground of the heads 14b of the plurality of piles 14 in the square cylindrical steel sheet pile wall 13, and the vertical supporting force can be increased.

  In addition, the rigidity around the newly reinforced concrete footing 15 is further increased by the increase in internal pressure accompanying the improvement of the ground inside and outside the square cylindrical steel sheet pile wall 13. Furthermore, the rigidity of the square cylindrical steel sheet pile wall 13 has the effect of suppressing deformation around the footing 15 and the square cylindrical steel sheet pile wall 13 itself has deformation resistance (ring effect), so that it is level 2 class. The horizontal displacement and rotation of the footing 15 when the seismic load is applied can be suppressed, and the earthquake resistance can be improved. As a result, it is possible to improve the yield strength of the newly installed foundation structure 10 ″.

  In each of the above embodiments, the rectangular steel sheet pile wall 13 is embedded around the footing construction planned position of the ground 11, but the shape of the annular underground wall may be cylindrical, and this steel sheet pile wall Instead of 13, a column-shaped soil cement wall (annular underground wall) is used to create a column-type continuous underground wall to a depth that is effective for the horizontal resistance of multiple piles (for example, 1 / β to π / 2β) You may form by a construction method etc. If an annular underground wall is formed with a soil cement wall instead of the steel sheet pile wall 13, the optimum seismic reinforcement for the work site can be implemented at a lower cost depending on the ground conditions and the state of the existing pier. Moreover, you may form a ring-shaped underground wall using a cast-in-place pile wall, a ready-made pile wall, etc. instead of a soil cement wall as a column-column type underground continuous wall.

  Furthermore, according to each of the embodiments described above, a case where a ground underground pier is newly installed as a new foundation structure has been described, but it is needless to say that each of the embodiments can be applied to an underwater pier (a new underwater foundation) such as a river crossing section. It is. In addition, according to each of the above embodiments, the entire area of the ground in the annular underground wall has been solidified and improved. For example, the central ground in the annular underground wall is left untreated, and the like. Of course, only a part of the ground in the wall may be solidified and improved.

It is sectional drawing which shows the new foundation structure of 1st Embodiment of this invention. (A) is sectional drawing which shows the state which embedded the underground wall in the ground of the said 1st Embodiment, and improved the ground in the underground wall, (b) is the ground and ground improvement in the underground wall. It is sectional drawing which shows the state which drilled the part which carried out. It is sectional drawing which shows the state which laid the new pile in the drilled part of the ground improvement of the said 1st Embodiment. These are sectional drawings which show the state which excavated the ground in the underground wall of the said 1st Embodiment. It is sectional drawing which shows the state which built the new footing on the head of the new pile of the said 1st Embodiment. It is sectional drawing which shows the new foundation structure of 2nd Embodiment of this invention. (A) is sectional drawing which shows the state which buried the underground wall in the ground of the said 2nd Embodiment, and improved the ground in the ground inner wall, (b) is the same ground wall and the part which improved the ground It is sectional drawing which shows the state which drilled the ground in the ground wall and the part which improved the ground while improving gaps. It is sectional drawing which shows the state which laid the new pile in the drilled part of the ground improvement of the said 2nd Embodiment. These are sectional drawings which show the state where the ground in the underground wall of the said 2nd Embodiment was excavated. It is sectional drawing which shows the state which constructed the new footing on the head of the new pile of the said 2nd Embodiment. It is sectional drawing which shows the new foundation structure of 3rd Embodiment of this invention. (A) is sectional drawing which shows the state which improved the ground of the said 3rd Embodiment, (b) is sectional drawing which shows the state which buried the underground wall in the part which improved the ground. It is sectional drawing which shows the state which drilled the ground in the underground wall of the said 3rd Embodiment, and the part which improved the ground. It is sectional drawing which shows the state which laid the new pile in the drilled part of the ground improvement of the said 3rd Embodiment. It is sectional drawing which shows the state which drilled the ground improvement part of the said 3rd Embodiment. It is sectional drawing which shows the state which constructed | assembled the new footing on the head of the new pile of the said 3rd Embodiment. It is sectional drawing which shows the new foundation structure of a prior art example.

Explanation of symbols

10, 10 ', 10 "New foundation structure section 11 Ground 12 Support layer (predetermined position)
13 Square steel sheet pile wall (annular underground wall)
13a Inner peripheral surface (inner surface)
14 Pile 14a Tip 14b Head 15 Footing 15a Outer surface A Solidification improvement part D Stuffing improvement part

Claims (3)

A new foundation structure in which an annular underground wall is embedded around the planned footing construction position of the ground, and footings are constructed on the heads of multiple piles whose tips are driven into a predetermined position in the annular underground wall. In
The annular underground wall is buried to a depth effective for the horizontal resistance of the plurality of piles, and the ground in the annular underground wall is solidified to a depth effective for the horizontal resistance of the plurality of piles. New foundation structure characterized by improvements. A new foundation structure in which an annular underground wall is embedded around the planned footing construction position of the ground, and footings are constructed on the heads of multiple piles whose tips are driven into a predetermined position in the annular underground wall. In
The annular underground wall is buried to a depth effective for the horizontal resistance of the plurality of piles, and the ground in the annular underground wall is solidified to a depth effective for the horizontal resistance of the plurality of piles. A new foundation structure improved and further solidified and improved in the space between the inner surface of the annular underground wall and the solidified portion. A new foundation structure in which an annular underground wall is embedded around the planned footing construction position of the ground, and footings are constructed on the heads of multiple piles whose tips are driven into a predetermined position in the annular underground wall. In
The annular underground wall is buried to a depth that is effective for the horizontal resistance of the plurality of piles, and the inner and outer grounds of the annular underground wall are within an effective range for the horizontal resistance of the plurality of piles. New foundation structure characterized by solidification and improvement to depth.

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