Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/22—Piles
  • E02D5/62—Compacting the soil at the footing or in or along a casing by forcing cement or like material through tubes
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
  • E02D7/28—Placing of hollow pipes or mould pipes by means arranged inside the piles or pipes
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D2250/00—Production methods
  • E02D2250/0061—Production methods for working underwater
  • E02D2250/0076—Drilling
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D2300/00—Materials
  • E02D2300/0004—Synthetics
  • E02D2300/0018—Cement used as binder

Definitions

• the present invention relates to a method of excavating a pile hole and burying a ready-made pile, and a foundation pile having a ready-made pile buried in a pile hole formed based on this method.
• a method of excavating a pile hole and burying a ready-made pile, and a foundation pile having a ready-made pile buried in a pile hole formed based on this method Regarding the structure. Above all, ground
• Non-Patent Document 1 a drilling head formed with a drilling head and an earth removal spiral is inserted into the hollow part of a ready-made pile, and the drilling hole protruding from the tip of the ready-made pile is inserted.
• the existing piles were being laid while excavating the stratum.
• the excavation diameter of the excavation head was slightly smaller (about minus 4 Omm) than the inner diameter of the ready-made pile to be buried (Non-Patent Document 1).
• the excavation blade (Patent Literature 1) that swings to the excavating head and excavates can be extended perpendicular to the axis of the excavating rod.
• the excavation blade protruding in the direction (horizontal direction) was formed, and the excavation of the expanded root compaction was performed.
• Patent Literature 35 discloses an invention aimed at reducing the amount of unloaded soil, since the existing piles were exclusively used because they could not be used.
• Patent Document 1 Japan. JP-A-8-291682
• Patent Document 2 Japan. JP-A-2-108724
• Patent Document 3 Japan. JP-A-57_74534
• Patent Document 4 Japan. JP-A-2002-54135
• Patent Document 5 Japan. Japanese Patent Application Laid-Open No. 2002-81059
• Non-Patent Document 1 Japan. “Study on pile foundations: from design to construction”
• drilling rods for digging have a structural limitation that they must pass through the hollow part of a ready-made pile (usually concrete), and even if the diameter can be expanded relatively easily (Patent Document 2), It must take three positions: the hollow part passing state (minimum diameter), the pile hole shaft excavation state (intermediate diameter), and the pile hole excavation part excavation state (maximum diameter).
• the excavation diameter of the consolidation part is up to about 1.2 times the shaft diameter of the pile hole. Even if the excavating head was equipped with a swinging arm with an excavating blade, the limit was 1.5 times.
• the tip of a ready-made pile is positioned directly above a drilling head, and excavation is performed while sinking the ready-made pile. It was not possible to excavate the enlarged diameter part.
• a p Tip cross section of ready-made pile
• the cross-sectional area of the tip of the ready-made pile corresponds to the area of adhesion to the soil cement layer that contributes to the propagation of shear force due to the load.
• L The length of the ground that allows for the peripheral frictional force of the pile
• N ave Average N value of the section that uses pile circumference fixative
• An object of the present invention is to improve the outer peripheral portion of a shaft portion of a pile hole in order to increase Rf, and to improve the ground strength as a whole peripheral surface of a ready-made pile. This will secure and increase the overall frictional resistance of the peripheral surface of the ready-made pile, and increase the stress propagation area so that the stress can be widely relaxed and propagated. That is, in the above-described formula of R f , N or coefficient C is increased.
• An object of the present invention is to form a rooted portion having a high solidification strength that can propagate. That is, in the above equation, ⁇ and Ap are increased.
• Another object of the present invention is to reduce the amount of soil discharged from the hollow portion of a ready-made pile to the ground when excavating a pile hole in the excavation method.
• Patent Document 3 discloses a method in which a steel pipe having a metal fitting which can be screwed into the ground at the tip in advance and which is used as a reinforcement is screwed into the ground as a casing.
• An invention is disclosed that realizes a reduction in earth removal by a method of inserting a).
• the ready-made pile is simply placed on the metal fittings, and there is no integration between the ready-made piles and the metal fittings, and the solidification of the soil cement layer, etc., that ensures the stress propagation between the ground and the ready-made piles Due to the lack of consideration for the mixed layer, high bearing capacity cannot be expected.
• this method requires metal fittings, it cannot be applied to the excavation method at all.
• the invention of Patent Document 4 is a pre-drilling method in which a pile hole having a diameter equal to the outer diameter of a ready-made pile is excavated, and then a ready-made pile having a spiral wing is buried. It is disclosed that the diameter of the shaft of the pile hole is made relatively small to reduce the amount of excavated soil.
• the invention of Patent Document 4 when screwing the spiral wing, a large twist is generated in the ready-made pile, and when the ground is hard, a huge torsion is generated in the ready-made pile, and it is impossible to perform with a ready-made concrete pile. is there.
• Patent Document 5 discloses that a propulsion head having a spiral wing and an excavating blade is fitted to the lower end of a hollow prefabricated pile, and the propulsion head is rotated by a rotating mouth through the prefabricated pile. A method of rotating and penetrating a ready-made pile without rotation is disclosed.
• a pile hole including a shaft portion of a pile hole is excavated with a larger excavation diameter than the conventional one (relative to the pile diameter of a ready-made pile), and further excavation of the pile hole is performed.
• a configuration was adopted in which a pile hole was excavated while forming a solidified mixed layer at least in an appropriate section within the desired depth range for design.
• the excavation head of the excavation hole protrudes from the tip of the hollow part of the prefabricated pile, excavates the ground to lower the prefabricated pile while forming a pile hole, and
• the pile excavation method of burying the ready-made pile in the hole
• the second invention is characterized in that a drilling head of a drilling rod protrudes from the tip of the hollow portion of the ready-made pile, excavates the ground, lowers the ready-made pile while forming a pile hole, and places the ready-made pile in a predetermined pile hole.
• a drilling head of a drilling rod protrudes from the tip of the hollow portion of the ready-made pile, excavates the ground, lowers the ready-made pile while forming a pile hole, and places the ready-made pile in a predetermined pile hole.
• a solidified mixed layer is formed at a predetermined depth range determined by design to restore and strengthen the ground strength, and normal pile drilling is performed in depth ranges other than the depth range.
• a cement hole is formed with a diameter larger than the outer diameter of a ready-made pile, and when excavating a predetermined depth range determined by design, cement milk is injected into excavated soil. 3.
• a pile hole is formed with a diameter of 1.4 times or more the outer diameter of the ready-made pile, and a predetermined depth range determined by design is excavated. At this time, a method of excavating soil by injecting cement milk into the excavated soil and stirring and mixing the excavated soil to form a solidified mixed layer having a predetermined solidification strength.
• the excavation head of the excavation rod is protruded from the tip of the hollow portion of the prefabricated pile, and the prefabricated pile is lowered while excavating the ground to form a pile hole.
• Pile holes are formed with a diameter of at least 1.4 times the outer diameter of the ready-made pile, and cement milk is injected into the excavated soil in a depth section including a relatively soft stratum on the ground, and the excavated soil is formed.
• This is a method for excavating piles, characterized by forming a solidified mixed layer with a predetermined solidification strength by stirring and mixing.
• the drilling head of the drilling rod protrudes from the tip of the hollow portion of the ready-made pile, excavates the ground to lower the ready-made pile while forming a pile hole, and places the ready-made pile in a predetermined pile hole.
• the pile digging method to bury the pile In the pile digging method to bury the pile,
• the drilling head of the drilling rod protrudes from the tip of the hollow part of the ready-made pile, excavates the ground, lowers the ready-made pile while forming a pile hole, and moves the ready-made pile into a predetermined pile hole.
• the pile digging method to bury the pile In the pile digging method to bury the pile,
• the excavation head of the excavation hole protrudes from the tip of the hollow portion of the prefabricated pile, excavates the ground to lower the prefabricated pile while forming a pile hole, and In the pile excavation method of burying the ready-made pile in the hole,
• a tip fitting is connected to a tip of the ready-made pile, and a drilling head is protruded from the tip of the tip fitting to excavate the ground to make a pile hole.
• the tip fitting is provided with one or more support surfaces on the outer surface of the cylindrical base, which can transmit the shear force upward and downward and can be used as tip support force.
• the excavation head is formed from the tip of the prefabricated pile by using a prefabricated pile having an uneven portion formed on the outer surface of the lower end of the pile shaft. And excavate the ground to form a pile hole, and the uneven portion of the ready-made pile propagates upward or downward on the outer surface of the lower end of the ready-made pile, as a tip supporting force.
• This is a method of excavating piles, characterized by forming one or more support surfaces that can be used.
• a tip fitting having a lateral projection formed on an outer surface of a cylindrical base is connected to a tip of the ready-made pile, and This is a method of excavating piles by protruding an excavation head from the tip and excavating the ground to form pile holes.
• the outer diameter of the solidified mixed layer and the outer diameter of the pile-fixing portion of the pile hole are formed to be substantially the same outer diameter. It is a method of digging a pile.
• a thirteenth invention is a foundation pile structure in which a ready-made pile is buried in a pile hole
• the pile hole is constructed by restoring and improving the ground strength at least in a depth range predetermined by design, and the ready-made pile is provided with a tip fitting at a lower end thereof, and the tip fitting is an outer surface of a cylindrical base.
• a foundation pile structure characterized in that a support surface capable of transmitting a shearing force and being used as a tip supporting force is formed at one or a plurality of locations in an obliquely upward or obliquely downward direction. It is.
• the relatively soft stratum mentioned above is the ground where ready-made piles are to be buried, and one of the pile holes has a strength smaller than the assumed ground strength compared to the assumed ground strength.
• ground with only ground strength For example, if the assumed ground strength is assumed to be "20" in an N value in sandy soil, it has a value significantly lower than the average N value, for example, an N value having a value smaller than "5". It refers to the ground that can hardly be considered as bearing capacity.
• the assumed ground strength may be set for each pile hole, or may be set for the entire site.
• cement milks refer to cement milk which solidifies after a lapse of a predetermined time if mixed into excavated soil and a hydraulic material equivalent to cement milk.
• the “predetermined depth range determined by design” means that the normal ground is formed from strata of various ground strengths, and which depth range is set depends on the strength of the entire foundation pile structure. Determine the range to be enhanced. That is, when the soft stratum is defined as the “predetermined depth range”, or when the middle layer having relatively strong ground strength is defined as the “predetermined depth range”, the soft strata are appropriately combined and set as the “predetermined depth range”. Or a certain depth range is defined as a “predetermined depth range” regardless of the ground strength.
• the “propagation of shear force” in the above refers to “a ready-made pile with the tip 13 attached” or “a pre-made pile with a convex portion on the outer surface of the lower end” in the solidified cement layer in the pile hole.
• the “supporting surface that can transmit the shearing force” is a projection (for example, an annular projection) on the “outer surface of the cylindrical base (steel pipe body) 6 of the tip metal fitting” or the “outer surface of the lower end of the prefabricated pile”.
• the lower surface of the projection 10 constitutes a support surface B to which the shear force can be propagated downward, and the upper surface of the projection 10 propagates the shear force upward.
• a support surface A that can be Figure (a)
• the upper and lower surfaces of the projection 10 are surfaces slightly inclined with respect to the vertical surface.
• the direction in which the shear force propagates acts obliquely to the vertical plane, so that it is desirable to form the shear force at right angles to the propagation direction.
• a side wall surface of the concave portion constitutes each of the support surfaces A and B.
• the supporting surface is not limited to the protrusion or the concave portion, and a step is formed on the outer surface of the cylindrical base 6 to be the supporting surface A or the supporting surface B having the same function.
• Fig. 4 (c) (d) the shape is arbitrary.
• the outer surface of the cylindrical base 6 (the lower shaft 36 when the annular projection 37 is formed on the ready-made stake 1; FIG.
• the cylindrical base 6 (or the lower shaft 36 in FIG. 2 (a)) is desirably cylindrical in view of the balance of stress propagation, but its shape such as a square tube is arbitrary.
• the outer diameter D " is of the tubular base part 6 of the end bracket 1 3, if a diameter smaller than the outer diameter of the prefabricated pile 1 (Du ⁇ D ⁇ ;) , the outer diameter D 01 of the prefabricated pile 1 desirable since it suffices drilling Kuiana corresponding. in this case, the upper end of the tubular base part 6, to form a large diameter portion 7 corresponding to the outer diameter D 01 of the prefabricated pile 1 (FIG. 2 (b )).
• the outer diameter D 13 of the annular projection 10 forming a supporting lifting surface the outer diameter D 01 of the prefabricated pile 1 (i.e., a smaller diameter than the outer diameter) of the large diameter portion 7 (D 13 ⁇ D 01), or the outer diameter D 13 can in be a larger diameter than the outer diameter D 01 of the prefabricated pile 1 (D 01 ⁇ D 13) .
• D 13 D 01, it is also to possible.
• the outer diameter D 13 is better not greater than D 01 resistance when the input ⁇ prefabricated pile is small, it is effective in the construction of the ground, such as high ground intensity (or density of the soil).
• the outer diameter D i of the tubular base 6 is made equal to the outer diameter D 01 of the ready-made pile 1 (Doi ⁇ Di!), Or the outer diameter D cruof the tubular base 1 is changed to the outer diameter of the ready-made pile 1. Can be larger than D 01 These dimensions can be selected depending on the ground strength, soil density, required strength of foundation piles, and so on.
• a small diameter lower shaft portion 36 is formed in the ready-made pile 1.
• the annular projections 37, 37 are formed in this portion (FIG. 2 (a))
• the outer surface 1 of the cylindrical base 6 corresponds to the outer surface of the lower shaft portion, and is set to have the same configuration.
• a solidified mixed layer is formed in a predetermined section, and the ground is pressed by the outer peripheral wall of the ready-made pile without discharging excavated soil. As a result, it is possible to demonstrate about twice the bearing capacity.
• N value when drilling a pile hole with a large diameter in an appropriate section and injecting cement milk to form a solidified mixed layer, it is possible to further restore and reinforce the pile circumferential friction force Therefore, it is expected that the support capacity will surely be increased.
• the conventional excavation method has the disadvantage that a large amount of excavated soil is discharged, but in the present invention, the diameter is larger than the outer diameter of the ready-made pile (for example, about 1.4 times or more the outer diameter of the ready-made pile).
• the diameter is larger than the outer diameter of the ready-made pile (for example, about 1.4 times or more the outer diameter of the ready-made pile).
• the solidified mixed layer is formed in the excavated pile hole, if the solidified mixed layer can adhere to the outer peripheral surface of the ready-made pile integrally, a ready-made pile having a large-diameter annular protrusion on the outer periphery can be constructed, so it is adjacent If the solidified mixed layer is formed at the same depth with the foundation pile and can be constructed before solidification, adjacent solidified mixed layers can be connected to each other, realizing a stronger foundation pile structure as an interconnected group it can.
• the outer diameter of the solidified mixed layer By making the outer diameter of the solidified mixed layer approximately the same as the diameter of the piled-up part, the drilling work for the pile hole is simplified, the control process is simplified, and the reliability of the drilling head is also improved. improves. Also, the outer diameter of the solidified mixed layer can be more than 1.5 times the outer diameter of the foundation pile. Drilling heads can be easily realized.
• this construction method can significantly reduce The amount of soil can be reduced.
• FIG. 1 (a) shows a ready-made pile and a drilling rod according to an embodiment of the present invention, and is an enlarged front view of a broken ready-made pile
• FIG. 1 (b) is a basic pile of the present invention. Structure.
• FIG. 2 is an enlarged front view of a reinforced portion of the foundation pile structure, and (a) and (b) are embodiments of the present invention.
• FIG. 3 is a vertical cross-sectional view for explaining the excavation method of the present invention.
• FIGS. 4 (a;) to (d) are schematic longitudinal sectional views for explaining the support surface of the tip fitting and the propagation of shearing force according to the present invention.
• FIG. 5 is a front view of another excavating head used for carrying out the present invention.
• Fig. 6 is an enlarged front view of the foundation of the foundation pile structure, showing a comparative example excavated by the pre-drilling method.
• the excavated head 18 excavates the pile hole 28 and lowers the ready-made pile 1 into the pile hole 28 formed by loosening the ground (Fig. 3 (a) to (c). )).
• the excavation diameter of the pile hole 28 excavated by the excavation head 18 is larger than the outer diameter of the ready-made pile 1 to be set, for example, about 1.4 to 1.5 times as large as the excavation from the ground 25.
• the excavated soil is not discharged during excavation and when the ready-made piles are laid, it is not always necessary to provide a conventional function for discharging soil (such as a spiral) in the middle of the excavated rod.
• the drilling rod When excavating ground with high ground strength or ground with very high soil density, if the application speed is to be increased, the drilling rod must be partially connected to the drilling rod in order to reduce the penetration resistance of the ready-made pile. It is also effective to form a normal spiral (discharge function) or to form a small-diameter spiral and to discharge a little amount of soil.
• the outer periphery of the ready-made pile 1 immediately reaches the ground through a pile fixed liquid layer having a thickness of 1 to 2 cm, but in the present invention, in the solidified mixed layer, the solidified mixed layer is It is formed thick, and the entire outer periphery of the solidified mixed layer (outer diameter) is in contact with the ground.
• the outer diameter of the ready-made pile 1 is 600 mm
• the outer diameter of the solidified mixed layer will be about 840 to 90 Omm, and in order to secure a sufficient thickness for transmitting the stress, the solidified mixed layer
• the thickness (vertical length) is preferably lm or more from the viewpoint of strength.
• the large-diameter excavation of the present invention appropriately loosens and loosens the ground, so even though the excavated soil is not discharged, concrete-made pre-fabricated piles with irregularities on the outer surface can also be laid, so almost all The foundation pile without soil can be created.
• steel pipe precast piles which are thinner than concrete precast piles, are easier to settle down, so steel pipe precast piles can also be used.
• the excavated soil that has been injected due to the solidification agent is discharged, so it is desirable that the solidified mixed layer be as small as possible.
• a solidifying agent for example, high-concentration cement milk is used, poured into the excavated soil, and stirred and mixed with the excavating head 18 to form a solidified mixed layer (soil cement layer) 29 A, 29 B
• the adhesive strength between the inner peripheral surface of the solidified mixed layer (soil cement layer) 29 A and 29 B and the outer peripheral surface of the ready-made pile 1 is equal to the outer peripheral surface of the solidified mixed layer 29 A and 29 B. Greater than the bond strength with the ground surface is necessary to improve stress propagation It is.
• the donut-shaped solidified mixed layers 29 A and 29 B attached to the outer periphery of the ready-made pile 1 solidify and act as annular projections of the ready-made pile. That is, a vertical load or pulling force is applied to the ready-made pile 1 and a shear force can be propagated from the upper and lower surfaces of the solidified mixed layer to the upper and lower ground layers, thereby enhancing the vertical supporting force and pulling force (Fig. 1 (b)). (Shown by a chain line arrow).
• the excavating head 18 is closed, and the excavated pile 1 is pulled up to the ground 25 through the hollow part 2 of the pile 1 (Fig. 3 (3)).
• the tip of the ready-made stake 1 is sunk into the stake of the pile hole 28, which is filled with cement milk (exists in the form of soil cement), and the lower surface of the stake 1 is fixed from the bottom of the stake. Leave only the length.
• the burying of the ready-made pile 1 is completed, and after the cement milk solidifies, the foundation pile structure 33 is formed (Fig. 1 (b)).
• an excavation port provided with a spiral for excavation and agitation on the body or upper part of the excavation head 18 (shown in the figure). Absent). The purpose is to remove excavated soil as much as possible from the embankment, or to mix and mix cement milk and excavated soil for + minutes to form a high-quality embankment layer 30.
• the ready-made pile 1 used in the middle digging method according to the present invention is integrated with the stiffening layer 30 in the stiffening layer 30 made of cement milk formed in the stiffening portion, and has a high vertical bearing capacity. And a projection with a large attachment area (or Prefabricated pile 1 with spiral wings) is desirable.
• the tip fitting 13 with the cylindrical steel pipe main body 6 with a projection as the base is replaced with the ready-made pile 1 It is desirable to mount it on the tip 3.
• this tip metal fitting 13 has a cylindrical steel pipe main body 6 that is not larger than the outer diameter of the prefabricated pile 1 in order to increase the adhesion area with the protrusion, and the outer diameter of the protrusion is at the top to reduce the pushing resistance.
• the outer diameter should be equal to or less than the outer diameter of the ready-made pile 1 to be mounted, and the number of projections should be the number that matches the required area of attachment with the required consolidation layer 30. Appropriate in terms of power balance.
• the ready-made pile 1 is laid, it is necessary to prevent the soil and mud from adhering to the protruding surface of the tip fitting 13 and to increase the adhesion in the consolidation layer 30. It is desirable to increase the attachment area by slightly increasing the outer diameter of the prefabricated pile 1 or to taper the upper and lower surfaces of the projection.
• the initial settlement after the solidification layer 30 is solidified can be prevented.
• the outer diameter of the steel pipe main body 6 located at the base of the projection should be as small as possible, and the outer diameter of the projection should be set at the upper part so as to minimize penetration resistance when laying the existing pile. It is desirable that the dimensions be approximately the same as the outer diameter of 1 and not too large. In other words, considering the propagation of shear force generated from the projecting surface involved in bearing capacity, at least the outer surface (lower surface or upper surface) of the protrusion has the required size and shape, and the soil cement layer has a higher solidification strength than the ground strength. Is indispensable.
• the surface area of the protruding part of the tip fitting 13 is designed to be large in order to secure the bonding strength between the surface of each part of the tip fitting 13 and the stiffening layer (soil cement layer) 30 of the stiffening part.
• mud adheres to the surface of It is necessary to prevent the wearing strength from decreasing.
• the height position where the pile hole 28 is excavated to form the soil cement Since the tip 3 of the ready-made pile 1 is located directly above (the position of the excavation head 18), consideration must be given to the attachment between the tip fitting 13 and the rooting layer 30.
• the upper and lower surfaces of the protruding portion are not horizontal but inclined surfaces, so that they are knotted or slightly larger than the outer diameter of the upper pile to prevent soil and mud from being caught on the upper surface when protruding.
• the drilling rod 15 used in the inner digging method of the present invention can excavate a pile hole with an outer diameter of 1.5 to 1.5 times the outer diameter of the ready-made pile 1 when opened.
• a drilling head 18 that can be closed with an outer diameter less than its inner diameter so that it can pass through the hollow part 2 of the ready-made pile 1 by diameter. That is, the excavating head 18 needs a structure having a large ratio between the diameter reduction and the diameter expansion.
• a digging arm 21 having a digging blade 22 at its tip is swingably attached to both sides of a head body 19 that can be connected to the mouth body 16 (Fig. 1 (a)). .
• the outer diameter of the protrusion of the tip metal fitting of the ready-made pile 1 (or the protrusion formed on the outer periphery of the lower end of the ready-made pile) is larger than the outer diameter of the shaft of the ready-made pile. Even if it does, the ready-made pile 1 can be easily penetrated and buried in the pile hole 28 if it has a shape (for example, a spiral wing, etc.) in consideration of the resistance at the time of penetration.
• the excavation head 18 used in this method is Since a drilling diameter of at least 1.4 to 1.5 times the outer diameter of the ready-made pile 1 is required, The use of two excavating heads 18 with a structure having the excavating arms 21 and a structure having high rigidity and strength was achieved by using two excavating arms.
• the rod body 16 of the excavation rod 15 can omit a spiral mainly used for earth removal as in a conventional drilling hole for a middle excavation.
• Stabilizer function for aligning the core of pile hole 2 8 and the core of hollow part 2 of ready-made pile 1 with the core of drilling rod 15 and a member with the function of stirring the excavated soil around drill rod 15 ( Figure 1 (a)).
• the size of the excavation diameter is adjusted (by adjusting the ratio of the excavation diameter of the excavation head 18 to the outer diameter of the ready-made pile 1).
• the ready-made pile 1 can be sunk quickly and the setting speed of the ready-made pile 1 can be controlled, an excavation head suitable for large-diameter excavation is required in order to further improve the excavation and crushability of the ground.
• the outer cylinder 41 is attached to the cylindrical head body 19 so as to be able to move up and down, the upper arm 42 at the upper end of the head body 19, and the lower arm at the lower end of the outer cylinder 41.
• the lower end of 43 can be connected with a pin, and the lower end of the upper arm 42 and the upper end of the lower arm 43 can be connected with a pin to form the excavating head 18 (Fig. 5).
• the excavating arm 21 is composed of the upper arm 4 2 and the lower arm 4 3, and the excavating blades 20 and 20 are provided at the lower end of the outer cylinder 4 1, and the excavating blades 2 and 2 are provided on the lower surface side of the upper arm 4 3. 2 is formed.
• the outer cylinder 41 and the head body 19 are moved up and down relatively so that the upper arm 42 and the lower arm 43 of the excavation arm 21 overlap (horizontally).
• the drilling diameter can be enlarged and the driving range can be extended, so that the diameter of the drilling arm is reduced compared to a normal drilling head (the upper arm 4 2 and the lower arm 4 3 of the drilling arm 21 are arranged vertically).
• the drilling blades can be formed in multiple stages, so that the grinding performance can be controlled. Therefore, with this excavating head 18, large-diameter excavation and agitation with a pile diameter ratio of at least twice the diameter of an existing pile is possible, and it is possible to exert a greater supporting force.
• the excavation head 18 may be provided with a plurality of stoppers in a vertical direction (not shown), and in this case, different excavation diameters can be easily accommodated. Therefore, by using the excavation head 18, the excavator (the rod body 16 of the excavation opening head 15) is mounted with one excavation head 18 while changing the excavation position and changing the diameter. Pile of When drilling holes, continuous excavation is possible only by adjusting the stopper. Also,
• the drilling diameter can be easily changed only by adjusting the stopper, and a solidified mixed layer with a different diameter is provided. Construction of the foundation pile to be performed becomes easy.
• a solidified mixed layer can be formed on a predetermined ground by excavating to about 1.4 to 1.5 times the outer diameter of the ready-made pile 1, so that the high-concentration
• the solidified mixed layer made of the cement also functions as an annular projection formed on the outer periphery of the ready-made pile 1.
• a solidified mixed layer with an outer diameter of about 120 to 1200 mm is formed. That is, the protrusion height (horizontal direction) (Projection distance)
• An annular projection of 160 to 20 O mm can be formed.
• the ready-made pile 1 and the solidified mixed layer 29 A, 29 B act integrally, so that the outer surface area of the ready-made pile is increased to increase the adhesion to the ground, and the vertical load or When a pull-out force is applied, the upper and lower surfaces of the solidified mixed layers 29A and 29B act as stress propagation surfaces, and the shear force effectively propagates from the upper and lower surfaces to the ground located above and below the soft ground To increase the bearing capacity (Fig. 1 (b)).
• the loosening of the ground reduces the frictional force around the piles of the ready-made piles.
• the frictional forces at the periphery of the piles of the ready-made piles can be restored by appropriately forming a solidified mixed layer, etc. It can be reinforced, and if it is constructed so that the adhesion between the solidified mixed layers 29 A and 29 B and the outer surface of the ready-made pile 1 is sufficiently enhanced, the support exerted on the shaft of the conventional ready-made pile 1 You can get about twice the supporting force.
• the surface area of the ready-made piles is substantially increased, and the stress propagation area of the ready-made piles is widened, so that the transmitted load stress (stress per area) to the surrounding weak ground is reduced and relaxed, Increase load capacity.
• the ready-made piles 1 were sequentially pushed in, The pushing resistance (penetration resistance) of the ready-made pile 1 is reduced, and the ready-made pile can be easily laid.
• the excavated rod does not need to have a spoiler-shaped excavated soil discharge mechanism, and the total amount of excavated soil can be reduced.
• the excavation diameter is significantly larger than before (for example, 1.4 times or more the diameter of ready-made piles) while loosening and loosening the ground.
• the excavation diameter is made larger than the outer diameter of the ready-made pile (for example, 1.4 times or more of the outer diameter of the ready-made pile) by the inside excavation method, thereby making it possible to reduce the amount of earth removal as a whole At the same time, a high bearing capacity can be realized.
• a cylindrical concrete pile with the following shape and size will be adopted. If the required proof stress is large, steel pipe-coated concrete piles (SC piles) can be selected (Fig. 1 (a), Fig. 2 (b)).
• SC piles steel pipe-coated concrete piles
• the large-diameter portion 7 forms a partially conical inclined slope in which the upper surface 8 has a horizontal plane shape and the lower surface 9 has a gradually decreasing diameter.
• the outer diameter of the connecting portion, i.e., the outer diameter D 13 of the large diameter portion 7 is a substantially equal to the outer diameter of the prefabricated pile 1 to be connected (the outer diameter of D 01 lower end).
• the width (height) of the large-diameter portion 7 is formed by a leaf 13 .
• the upper surface 11 of the annular projection 10 is formed in a horizontal plane, the lower surface 12 forms a partially conical slope, and the lower end of the slope reaches the lower end of the steel pipe body 6.
• the width of the annular projection 10 (height) is formed by L 13 (FIG. 2 (b)).
• the dimensions are formed as follows.
• the inner diameter of the steel pipe main body 6 is the inner diameter D of the ready-made pile 1 connected to the upper part. 2 and the thickness ti of the steel pipe body 6 is about 15 to 40 mm, so that the outer diameter D of the knot-shaped steel material of the annular projection 10! 3 is the outer diameter of the ready-made pile 1 at the top.
• the projection area the area of adhesion to soil cement
• the excavating head 18 is configured by swingably mounting the upper ends of the excavating arms 21 and 21 on both sides of a head body 19 that can be connected to the mouth head body 16 (FIG. 1 (a)).
• the head body 19 has a flat portion that tapers from the middle portion to the lower end portion, and excavation blades 20 and 20 project from the tip of the flat portion.
• the excavating arm 21 has an upper end attached to the head body 19 with a rotating shaft 24, and a middle part directed downward so that the head body 1 extends along the flat part of the head body 19.
• the lower end formed with the digging blades 22 and 22 is bent so as to approach downward and open outward together with the digging blades 22 and 22.
• the excavating arms 21 and 21 have low rotational resistance, are easy to swing, and the entire excavating head 18 is compact, so that it is easy to penetrate the hollow portion of the ready-made pile. Therefore, large-diameter excavation becomes easier.
• the head body 19 is provided with stoppers 23, 23 for limiting the range in which the excavating arms 21, 21 swing in accordance with the excavating diameter of the pile hole 28.
• the rod body 16 is provided with horizontal plates 17 and 17 symmetrically in diameter at predetermined heights (for example, 5 m), omitting the spiral for discharging the earth.
• the horizontal plates 17 and 17 combine the function of a stabilizer for aligning (centering) the axis of the drilling rod 15 with the axis of the pile hole 28 or the axis of the ready-made pile 1, and the function of stirring the excavated soil. Have.
• the operation mode of the excavating head 18 is as follows when excavating the pile hole 28 (during excavation of the shaft portion of the pile hole, excavating to form a solidified mixed layer, agitating, excavating the agglomeration section, and agitating) and the hollow space of the ready-made pile 1. It has been simplified to a two-step method when passing through part 2. By moving the excavating arm 21, the outer diameter is about 1.5 times (1200mm) of the outer diameter of the ready-made pile 1, and even if the excavating rod 15 does not have a discharging mechanism, reliable and stable excavation and agitation can be achieved. It was realized. [4] Excavation method
• the ground where the ready-made pile 1 is to be buried (mainly sandy soil) is from 25 above the ground, and 6.
• the excavation hole 15 passes through the hollow part 2 of the pre-made pile 1 with the tip fitting 12 and the hollow part 6 a of the tip fitting 13 and the tip fitting 13
• the drilling head 18 protrudes from the tip 14 of the drill.
• the drilling arm 21 swings until it is regulated by the stopper 23, and the swing angle
• the pile hole 28 can be excavated with the excavating blades 2 2 and 2 2 of the excavating arm and the excavating blades 20 and 20 of the head body 19 while maintaining the same.
• the shaft of the pile hole 28 having a diameter larger than the outer diameter of the ready-made pile 1 is excavated. While excavating, the excavating rod 15 is lowered and the ready-made pile 1 is lowered (Fig. 3 (a)).
• the height position where the solidified mixed layer is formed can be roughly grasped by the N value obtained by a standard penetration test in advance, it is desirable to form the solidified mixed layer at the height position where the N value is applicable. That is, the current value of the motor of the auger that rotates and raises and lowers the excavation hole 15 during excavation is measured, and the integrated current value is calculated for each predetermined height range (for example, 5 Ocm). If this is done, the ground strength can be compared at the same depth as the N value of the standard penetration test, and the height position indicating the integrated current value will be the corresponding ground to be improved. As a result, a solidified mixed layer can be formed at an accurate depth section.
• the ready-made piles 1 are sequentially laid while the ground is being improved, the outflow of the soil cement can be prevented, and the solidified mixed layers 29A and 29B can be reliably formed.
• cement milk solidification strength: 20 N / mm
• a pile hole is excavated to a predetermined depth (approximately 21 m), which is the supporting ground (N value: 30)
• cement milk solidification strength: 20 N / mm
• the excavated soil can be replaced with cement milk by discharging cement milk from the bottom of the consolidation section to push up the excavated soil.
• a stopper can be attached to the side of the head body 19 of the excavating head 18 where the excavating arms 21 and 21 swing when the excavating head 15 rotates in the reverse direction. In this case, in this case, if the drilling head 18 is pulled up while rotating in the reverse direction, the inner wall of the hollow part 2 of the ready-made pile 1 is not damaged, and the drilling head can be reliably recovered.
• the constructed foundation pile structure 33 is constructed (Fig. 1 (b), Fig. 2 (b)).
• this foundation pile structure 33 When constructing this foundation pile structure 33, the excavated soil is hardly discharged with a small amount of soil removal equivalent to the amount of cement milk injected, so the surrounding ground strength is compacted and high in the load test. A bearing capacity of 9300 kN (maximum load) is obtained. In addition, improvement in variation in settlement characteristics can be expected.
• the conventional inner digging method does not use the tip metal fittings 13 of this method, but uses the same diameter as the outer diameter 60 Omm of the tip metal fittings 13 in the consolidation layer of this method. This is compared with the conventional excavation method using a pre-made concrete pile. When a ready-made pile with an outer diameter of 60 O mm was used and the tip of the ready-made pile was similarly anchored in the consolidation layer, the maximum load was about 310 kN on the same ground.
• the timing for lowering the ready-made stake 1 is arbitrary as in the conventional digging method.
• the formed soil cement layers 29 A and 29 B it is desirable to install the ready-made pile 1 immediately after the formation of the layers.
• a solidified mixed layer was formed in which two sections of the formations 26A and 26B were improved and replaced with high-concentration soil cement layers 29A and 29B. Regardless of the size, it is possible to appropriately form a high-concentration soil cement layer in other sections to increase the bearing capacity of the shaft (not shown). Further, in the above-described embodiment, the solidified mixed layer is formed only in the section where the N value is particularly small, and a comprehensive solidified mixed layer having a high bearing capacity enhancing effect is created with a small amount of processing. Wataruconnection solidified strength full depth of 2 8 0. 5 NZmm 2 to form a solidified mixture layer below 1 high solidification strength for example in the ground have a better. oN / mm 2 approximately Soirusemento layer (the solidified mixture layer ) Can also be formed.
• the amount of excavated soil is not equal to the amount of newly added cement milk, etc. In order to reduce the amount of excavated soil, etc., it is desirable to minimize the injection of cement milk, etc.
• the ready-made pile 1 having the tip metal fitting 13 fixed at the lower end is buried.
• another ready-made pile 1 without using the tip metal fitting 13 can be used.
• a lower shaft portion 36 which is thinner than the upper shaft portion 34 is formed at a lower end portion, and a step portion (boundary portion) between the upper shaft portion 34 and the lower shaft portion 36, above the step portion, below the step portion ( Annular protrusions 37, 37 are formed on the lower shaft portion).
• a connecting pile, a lower pile as the above-mentioned ready-made pile, a steel pipe-coated concrete pile (SC pile) as the upper pile, etc.
• SC pile steel pipe-coated concrete pile
• the interval 2 between the annular projections 37 and 37 and the length L i 4 of the annular projection 37 from the lower shaft portion 36 are equal to the interval L t 2 between the large-diameter portion 7 and the annular projection 10 in the embodiment.
• the annular projection 37 has an inclined upper surface 37a and an inclined lower surface 37b, and the inclined lower surface 37b has the same function as the lower surface 9 of the large diameter portion of the steel pipe body 6 and the lower surface 12 of the annular projection 10.
• the inclined upper surface 37a is similarly formed.
• the length L 14 of the annular projection 37 is configured so that the inclined upper and lower surfaces 37 a and 37 b of the annular projection 37 can be as large as possible without protruding from the outer surface of the upper shaft portion 34. also, set in relation to the L 12 as described above.
• this prefabricated pile 1 is buried in the pile hole 28 in the same process as the prefabricated pile 1 to which the tip fitting 13 of the above-mentioned embodiment is fixed to form a foundation pile structure 33 (FIG. 2 ( a)).
• the outer circumference of the tip of the annular projection 37 has the largest outer diameter, soil and mud are likely to adhere thereto. Therefore, if the annular projections 37, 37 are covered by an appropriate method (not shown). However, a stable and larger supporting force can be exhibited in the root consolidation layer 30.
• a projection can be formed from a non-annular projection obtained by cutting the annular projection or a projection that is dispersedly arranged (not shown).
• an annular concave portion can be formed instead of the annular protrusion (convex portion) 37 (see FIG. Not shown).
• a drilling rod 15 having no spiral for discharging in the rod body 16 from the viewpoint of reducing the discharging. It is also possible to use a drilling rod in which a spiral having a smaller outer diameter is formed in a part or the whole of the mouth body 16 (not shown). This is effective when priority is given to increasing the excavation speed in areas where the ground strength is high, or when priority is given to removing excavated soil as much as possible from the inside of the consolidation.
• the drilling rod is provided with a certain amount of earth discharging mechanism to control the earth discharging amount, so that the construction speed and the earth discharging amount (the earth discharging processing amount). It can be seen that the foundation pile can be constructed more economically than in the past, because and can be appropriately combined.

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• Engineering & Computer Science (AREA)
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• General Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Paleontology (AREA)
• Civil Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Piles And Underground Anchors (AREA)
• Placing Or Removing Of Piles Or Sheet Piles, Or Accessories Thereof (AREA)
• Earth Drilling (AREA)

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• 2003
  • 2003-09-30 CN CNB038231085A patent/CN100510276C/zh not_active Expired - Lifetime
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  • 2003-09-30 KR KR1020057004993A patent/KR101071122B1/ko active IP Right Grant
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