JP4481472B2 - Pile foundation and foundation structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pile foundation used as a foundation of a building and a foundation structure using the pile foundation and a direct foundation in combination.
[0002]
[Prior art]
As a foundation structure generally adopted for a building, a pile foundation structure that supports the building 1 with a large number of pile foundations 2 as shown in FIG. 7 and a building 1 that is indicated by an arrow in FIG. 8 as shown in FIG. There is a direct foundation structure supported by ground reaction force 3. Pile foundations include driven foundations, embedded foundations and cast-in-place concrete pile foundations, and direct foundations include footing foundations and solid foundations.
[0003]
However, in the foundation structure using the pile foundation, since the number of piles is calculated on the assumption that the pile supports the entire weight of the building, the number of piles to be used becomes very large, and the construction period is Cost and cost.
[0004]
In addition, in the foundation structure based on the direct foundation, since the entire weight of the building is supported by the ground (ground reaction force), it cannot be established if the ground strength of the ground is not sufficient. In addition, as shown in FIG. 9, the subsidence occurs in the ground 5 particularly when the weight of the building 4 is uneven with respect to the foundation plane and is partially biased, causing serious damage to the building 4. There is a risk.
[0005]
Since there are disadvantages in both the pile foundation structure and the direct foundation structure, a foundation structure using both a pile foundation and a direct foundation as shown in FIG. 10 is proposed to compensate for these disadvantages. It has been implemented. That is, in the example shown in FIG. 10, the place where the weight of the building 4 is large is supported by the pile foundation 2, and the other place is directly supported by the ground (ground reaction force) 5.
[0006]
[Problems to be solved by the invention]
However, in such a foundation structure using a pile foundation and a direct foundation in combination, as shown in FIG. 10, it is reported that cracks 6 may occur at the boundary between these foundations or a step (not shown) may occur. Has been. This is due to the difference in settlement behavior between the pile foundation and the direct foundation, which is a fundamental problem when using the pile foundation and the direct foundation together. Therefore, the foundation structure using the pile foundation and the direct foundation in combination is not actively adopted at present.
[0007]
The present invention has been made in view of the above circumstances. The purpose of the present invention is to make up for the shortcomings of the pile foundation and the shortcomings of the foundation directly, and to combine these advantages with this foundation structure. It is to provide a pile foundation to be used.
[0008]
[Means for Solving the Problems]
The pile foundation according to claim 1 of the present invention is a pile foundation that is driven or embedded in the ground or a foundation slab, and the pile head portion is connected to the building to support the building. A first insertion body connected to the first insertion body, a second insertion body inserted into or inserted into the first insertion body, and one of the first insertion body and the second insertion body. An oil storage portion, and the wall of the oil storage portion presses the other wall surface of the first insertion body and the second insertion body by the oil pressure of the oil storage portion, The means for solving the above-mentioned problems is that a reaction force adjusting device including a friction generating means for increasing the frictional force during insertion between the insertion body and the second insertion body is provided.
[0009]
According to this pile foundation, the following effects are achieved by providing the reaction force adjusting device. Since the first insertion body or the second insertion body is provided with the friction generating means, the wall surface of the first insertion body or the second insertion body is pressed by the friction generation means, and the insertion between these insertion bodies is performed. The frictional force at the time is increased, so that the insertion between the first insertion body and the second insertion body is less likely to occur. Here, the frictional force for insertion is generally equivalent to the long-term support force of the pile, and the insertion starts when a force greater than that acts on the pile. Therefore, when consolidation settlement or the like does not occur in the ground directly under the building, the oil pressure of the friction generating means is adjusted so that the insertion between the first insertion body and the second insertion body does not occur. . When the ground directly under the building causes settlement such as consolidation under the condition that the friction generating means is adjusted in this way, the ground reaction force decreases and the load supported by the pile increases, but the reaction force adjustment device If the frictional force exceeds the value, the building will sink due to the insertion, and the ground reaction force will recover.
[0010]
In the foundation structure of the present invention, the foundation structure is a combination of a direct foundation using ground reaction force and a pile foundation using support force by a pile, and the above-mentioned reaction force adjusting device is provided as a pile foundation. It was set as the solution of the said subject to use the pile foundation which becomes.
[0011]
According to this foundation structure, as described above, the pile foundation is inserted when a certain level of force is applied to the ground directly below the building due to consolidation or other subsidence, and the applied force is maintained at the equivalent of the long-term bearing capacity of the pile. And a reaction force adjusting device that always keeps the building in contact with the ground. For this reason, when an excessive force is applied to the pile due to consolidation settlement or the like, the pile is protected by the reaction force adjusting device, and damage to the building is prevented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
FIG. 1 is a view showing an embodiment of the foundation structure of the present invention. In FIG. 1, reference numeral 10 denotes a foundation structure, and 11 denotes a building built on the foundation structure 10. The foundation structure 10 is a combination of a direct foundation portion 12 that uses the ground reaction force 3 and a plurality of pile foundations 13 that use the support force of the pile. In this example, the building weight W of the building 11 Among them, the load W1 corresponding to the supporting force is always applied to the pile foundations 13 and the other building weight W2 (= W−W1) is supported by the ground 5 (ground reaction force 3). In addition, since the weight W2 is supported by the ground 5 in this way, the ground 5 is subsidized to some extent (for example, consolidation subsidence), but this subsidence amount can be estimated in advance from the ground investigation, so that the reaction force adjustment is performed as described later It is possible to provide a movable amount (stroke) of the apparatus.
[0013]
The pile foundation 13 is an example of the pile foundation of the present invention, and is provided with a reaction force adjusting device 14 at the pile head portion as shown in FIG. As shown in FIG. 3A, the reaction force adjusting device 14 includes a steel pipe insert (first insert) 16 connected to the building 11 via, for example, a base plate 15, and the insert. The steel pipe pile 17a is integrally connected to the outer insert body 17, so that the inner insert body 16 and the extrapolation body can be extrapolated. The insertion direction with the body 17 corresponds to the length direction of the pile.
[0014]
At the upper end of the insert 16, a flange 18 is attached to the foundation plate 15 by anchor bolts or is touched to the foundation plate 15, whereby the pile foundation 13 is connected to the building via the foundation plate 15. 11 is connected. Further, a friction generating portion (friction generating means) 19 is provided at the lower end of the insert 16.
[0015]
The friction generating unit 19 includes an oil storage unit 20, oil 21 filled therein, and a hydraulic pressure adjustment valve 22 that adjusts the hydraulic pressure in the oil storage unit 20. The oil storage portion 20 is disposed at the lower portion of the insert 16 and is formed in an annular shape provided at the upper and lower ends of the steel pipe 20a having a smaller diameter than the insert 16 as shown in FIG. It consists of plates 20b and 20b, a film 23 attached in a state of covering the outside of the annular plates 20b and 20b, and a slit steel pipe 24 disposed in a state of covering the film 23. With such a configuration, the oil containing portion 20 is filled with oil 21 in a containing space surrounded by the steel pipe 20 a, the annular plate 20 b, and the film 23.
[0016]
The membrane 23 is made of a stretchable material such as synthetic rubber, and is oil-tightly sealed with the oil 21 filled in the oil container 20, and is easily expanded by hydraulic pressure as will be described later. The inner surface of the slit steel pipe 24 is pressed. As the oil 21, a viscous body (oil) used for a hydraulic damper such as silicon oil is used.
[0017]
The hydraulic pressure adjusting valve 22 penetrates the steel pipe 20a from the oil accommodating portion 20 and is drawn inside thereof, further passes through the steel pipe 20a to the inner insert 16 side, and passes through the insert 16 from there. It is attached to the pipe 25 drawn out, and is for controlling to set the pressure (hydraulic pressure) by the oil 21 filled in the oil container 20 to a predetermined pressure and to hold it. As the hydraulic pressure adjusting valve 22, various conventionally known ones such as an orifice type, a proportional valve type, and a combination type can be used.
[0018]
The position where the hydraulic pressure adjusting valve 22 is attached is close to the flange 18 of the insert 16 so that it does not interfere with the insertion between the insert 16 and the insert 17. It has become.
Further, since the hydraulic pressure adjustment valve 22 is provided outside the insert 16, the hydraulic pressure in the oil storage portion 20 by the hydraulic pressure adjustment valve 22 can be easily adjusted.
[0019]
The slit steel pipe 24 constitutes a wall body of the oil container 20, and as shown in FIG. 3 (c), a plurality of slits 26 are formed in parallel with each other at predetermined intervals along the length direction. Is. Under such a configuration, the slit steel pipe 10 is configured such that the thin plate portions 27 formed between the slits 26 and 26 by the formation of the slits 26 are respectively pressurized by the oil pressure of the oil storage unit 20. This facilitates deformation toward the outside, that is, toward the inner surface of the extrapolated body 17. In addition, the location where the slits 26 are formed in the oil storage portion 20 is a sliding portion that slides between the outer insertion body 17 as described later.
[0020]
On the slit steel pipe 24 of the oil storage part 20 of the friction generating part 19, in the part where the slits 26 are formed, that is, in the sliding part between the outer insertion body 17, the thin plate part 27 which becomes the sliding surface. Lubricant 28 is applied on top. This lubricant reduces the static frictional force when the outer insert 17 and the inner insert 16 are inserted and the inner surface of the outer insert 17 and the wall of the oil container 20, that is, the slit steel pipe 24 slide. Conventionally known lubricants can be used. In this example, molybdenum paste in which molybdenum powder is dispersed in a plastic material is used.
[0021]
In addition, between the upper end of the outer insert 17 and the side surface of the insert 16, a stretchable and watertight sheet 29 such as urethane is provided between the outer insert 17 and the insert 16. In addition, a disc-shaped plate 30 is provided in the outer insert 17 so as to close the inside of the outer insert 17 in a liquid-tight manner under the friction generating portion 19. ing. With such a configuration, the friction generating portion 19 is not affected by groundwater when the pile foundation 13 is buried underground.
[0022]
As shown in FIG. 1A, the number and arrangement of the pile foundations 13 are determined in advance according to the distribution of weight applied to the bottom surface of the building 11 and the like. And in order to embed this pile foundation 13, first, as shown to Fig.4 (a), the steel pipe pile 17a is driven into the ground 5 so that hard layers (not shown), such as a rock mass, may be reached. Next, as shown in FIG. 4 (b), the upper part of the ground 5 is excavated (primary excavation), and further, the excavation site is further excavated (secondary excavation) as shown in FIG. The upper end portion (stake head portion) of 17a is cut, and the reaction force adjusting device 14 shown in FIG. 3 (a) is welded to the cut portion, and the anchor 31 ... is attached to the flange 18 of the reaction force adjusting device 14. Keep it. Thereafter, as shown in FIG. 4D, the portion provided with the reaction force adjusting device 14 is backfilled, and the reaction device 14 and the base plate 15 formed on the ground 5 are connected using the anchors 31. .
[0023]
In this way, when the base plate 15 is placed on the flange 18 and fixed by bolting or the like, by adjusting the hydraulic pressure adjusting valve 22 prior to this, the frictional force by the friction generating portion 19 is adjusted, and all piles are adjusted. The foundation 13... Receives the load W 1 of the building weight W of the building 11 and supports it almost without sliding, and in a direction in which the inner insert 16 and the outer insert 17 are inserted into each other. When a force exceeding a certain level is applied, these are inserted relatively.
[0024]
The frictional force is adjusted by adjusting the oil pressure adjusting valve 22 to sufficiently increase the oil pressure in the oil accommodating portion 20 and causing the slit steel pipe 24 to bulge outward through the film 23.
[0025]
The pile foundation 13 thus arranged with the frictional force adjusted is normally supported by a preset load W1 in the building weight W of the building 11 as described above.
In addition, when the ground directly under the building is subsidized or the like, and a force exceeding a predetermined value is applied to the pile foundation 13, a thin plate of the insert 16 is received in the external insert 17 by receiving this force. The part 27... Slides, whereby the pile foundation 13 contracts and the foundation plate 15 comes into contact with the ground. Then, the pile foundation 13 comes to bear a force corresponding to the long-term supporting force again, and supports the building weight other than that by the ground reaction force.
[0026]
At this time, since the lubricant is applied on the thin plate portions 27..., The static frictional force on the sliding surface is small, and therefore the force exceeds the predetermined value adjusted and set by the hydraulic pressure adjusting valve 22. When is added, the sliding force immediately occurs and the applied force decreases.
[0027]
Here, the reduction mechanism by friction will be described. The frictional force includes a static frictional force generated just before starting to slide and a dynamic frictional force generated while sliding, but the dynamic frictional force is smaller than the static frictional force. Therefore, in this example, by applying a lubricant to the sliding surface that becomes the friction surface, the difference between the dynamic friction force and the static friction force is reduced, and the load P has a predetermined value as shown in FIG. The deformation δ hardly occurs before exceeding, and when the load P exceeds a predetermined value (when it reaches the predetermined value), the sliding (deformation) is caused quickly, and the force (load P) applied by the static friction force and further the dynamic friction force ).
[0028]
In the foundation structure 10 in which such a pile foundation 13 and the direct foundation portion 12 are used in combination, the ground 5 immediately below the building 11 is subsidized due to consolidation, particularly by providing the reaction force adjusting device 14 on the pile foundation 13. Occurs, the force is applied to the pile foundation 13 exceeding the predetermined value set by the hydraulic adjustment valve 22, the inner insert 16 and the outer insert 17 are inserted, and the bottom surface of the foundation plate 15 and the ground 5 are grounded. In addition, the force applied to the pile foundation 13 can be reduced to a long-term supporting force. On the other hand, when settlement such as consolidation does not occur, sliding hardly occurs due to frictional force generated on the sliding surface.
[0029]
In addition, for buildings where the weight is uneven with respect to the foundation, by adjusting the pile arrangement of the pile foundation 13, the ground reaction force can be made uniform and the uneven settlement of the ground 5 can be prevented. .
Moreover, since the pile foundation 13 and the foundation part 12 are used in combination, not only the horizontal resistance but also the decay attenuation to the ground 5 occurs at the time of the earthquake. Therefore, it is extremely earthquake resistant by combining with the action by the reaction force adjusting device 14 described above. It becomes a highly basic.
Furthermore, the number of pile foundations can be reduced to about 1/2 to 1/3 compared with the conventional pile foundation structure as shown in FIG. 7, and therefore it is extremely advantageous both in terms of cost and construction period. It becomes.
[0030]
Further, the reaction force adjusting device 14 used for such a pile foundation 13 has, for example, a diameter of a steel pipe forming the insert 16 of 300 mm, a hydraulic pressure of about 50 kg / cm ² , and a length of the slit 25 of about 1 m, If the friction coefficient on the sliding surface is about 0.25, the frictional force is about 120 tons, and it has an extremely high output function. Therefore, the reaction force adjusting device 14 of this example can easily set and adjust the frictional force of the sliding surface by changing the hydraulic pressure by the hydraulic pressure adjusting valve 22, so that the frictional force according to the weight of the building 11 can be adjusted. The power can be changed easily.
[0031]
In addition, in the reaction force adjustment apparatus 14 in the pile foundation 13 of the said example, although the friction generation part 19 was provided in the end (lower end) of the insertion body 16, this invention is not limited to this, A friction generation part is provided. By providing a hydraulic pressure on the wall of the oil storage portion of the friction generating portion provided on one end of the extrapolated body 17, the wall is recessed inwardly, The frictional force on the sliding surface may be increased.
[0032]
6 (a) and 6 (b) are diagrams showing an example of a pile foundation having a friction generating portion configured to exhibit such an action. In these drawings, reference numeral 40 denotes another pile foundation according to the present invention. It is an example. This pile foundation 40 is provided with a reaction force adjusting device 41 on the pile head portion in the same manner as the pile foundation 13 shown in FIG. 2 and FIG. 3A. For example, as shown in FIG. A steel pipe outer insertion body (first insertion body) 42 attached to a base plate 15 (not shown) and an insertion body (second insertion body) 43 inserted into the outer insertion body 42. The steel pipe pile 43a is integrally connected to the insert 43. For this type, as shown in FIG. 6 (c), all or part of the reaction force adjusting device can be installed in the base plate 15. In this case, a hydraulic pressure adjusting valve 48 to be described later is used. Can be provided on the base plate 15 by pulling out a pipe (not shown).
[0033]
A flange 44 that is bolted to or touched to the foundation plate 15 is attached to the outer insert 42 at the upper end thereof, whereby the pile foundation 40 is attached to the building via the foundation plate 15. It is connected. Further, a friction generating portion (friction generating means) 45 is provided at the lower end of the extrapolated body 42.
[0034]
The friction generating unit 45 has the same configuration as that of the friction generating unit 19 in the above example. The oil containing unit 46, the oil 47 filled in the oil containing unit 46, and the oil pressure adjustment for adjusting the oil pressure in the oil containing unit 46 are provided. It has a valve 48, and a film 49 and a slit steel pipe 50 are arranged inside the oil container 46. The oil accommodating portion 46 includes a steel pipe 46a having substantially the same outer diameter as the outer insert 42, annular plates 46b and 46b provided at the upper and lower ends of the steel pipe 46a, and inner peripheral edges of the annular plates 46b and 46b. It is composed of a film 49 attached to the film 49 so as to cover the space, and a slit steel pipe 50 provided so as to cover the inside of the film 49, and the slit steel pipe 50 is formed on the outer surface of the insert 43. It is comprised so that it may contact | abut.
[0035]
The film 49 seals the oil container 46 in a liquid-tight manner as in the case of the above example, and is made of a material having elasticity such as synthetic rubber and having excellent wear resistance. In addition, as the oil 47 filled in the oil containing portion 46, silicon oil or the like is used as in the above example. Furthermore, also in this example, a lubricant (not shown) made of molybdenum paste or the like is applied on the outer surface of the slit steel pipe 50 so that the static frictional force is lowered.
[0036]
The hydraulic pressure adjusting valve 48 is attached to a pipe (not shown) that passes through the steel pipe 46a and communicates with the oil accommodating portion 46, and applies a pressure (hydraulic pressure) by the oil 47 filled in the oil accommodating portion 46 to a predetermined pressure. It is for controlling to set and hold this. Note that the same hydraulic pressure adjustment valve 48 as in the previous example is used.
Moreover, in this pile foundation 40, the waterproof sheet 51 which consists of urethane etc. is stuck between the lower end of the friction generation part 45, and the side surface of the insertion body 43, and, thereby, the friction generation part 45 has the influence of groundwater. It is not to receive.
[0037]
In the pile foundation 40 having such a configuration, by adjusting the hydraulic pressure adjusting valve 48, the hydraulic pressure in the oil accommodating portion 46 is sufficiently increased, and the membrane 49 is bulged to the outer surface side of the insert 43. Further, the thin plate portion (not shown) of the slit steel pipe 50 is bulged outward to increase the frictional force with the inner insert 43, thereby making it difficult for insertion between them. Here, the frictional force for insertion is generally equivalent to the long-term support force of the pile, and the insertion starts when a force greater than that acts on the pile.
[0038]
And when consolidation settlement etc. do not arise in the ground just under a building, the oil pressure of the friction generation part 45 is adjusted so that the insertion between the outer insertion body 42 and the insertion body 43 may not occur. Then, when the ground immediately under the building is subsidized under the condition where the friction generating portion 45 is adjusted in this way, the ground reaction force decreases and the load supported by the pile increases. When the friction force of the force adjusting device 41 is exceeded, the building sinks due to the insertion, and the ground reaction force is recovered. Therefore, even if it exists in this pile foundation 40, there will exist the same effect as the pile foundation 13 of the said example.
[0039]
In the reaction force adjusting devices 14 and 41 in the pile foundations 13 and 40 in the above example, after adjusting the hydraulic pressure (that is, the frictional force by the hydraulic pressure) once with the hydraulic pressure adjusting valves 22 and 48, the reaction force adjusting devices 14 and 41 are used as they are. However, for example, when it is necessary to perform maintenance, a hydraulic gauge (not shown) indicating the hydraulic pressure in the oil storage portions 20 and 36 and a hydraulic valve 22b are provided on the upper surface of the base plate 15. When the hydraulic pressure obtained from this hydraulic gauge fluctuates with respect to a predetermined value, the hydraulic pressure may be adjusted and managed through the hydraulic valve 22b.
[0040]
Further, in the above example, the membranes 23 and 49 are attached to the oil containing portions 20 and 46 so as to constitute the wall body, the inside of the oil containing portions 20 and 46 is liquid-tight and the membranes 23 and 49 are oil The frictional force is increased by bulging with pressure, but the present invention is not limited to this. For example, without using the membranes 23 and 49, the oil containing portions 20 and 46 are made of a stretchable material such as synthetic rubber. A bag-shaped inner container made of a certain material may be stored, and the inner container may be filled with oils 21 and 47. If the bag-like inner container is used in this way, the risk of a decrease in hydraulic pressure due to oil leakage is reduced, and the long-term reliability of the reaction force adjusting devices 14 and 41 is further increased.
[0041]
【The invention's effect】
As described above, the pile foundation in the present invention is provided with friction generating means on the first insertion body or the second insertion body, and the friction generation means presses the wall surface of the first insertion body or the second insertion body. And since the frictional force at the time of the insertion between these insertion bodies is improved, the insertion between the 1st insertion body and the 2nd insertion body can be made hard to occur. Here, the frictional force for insertion is generally equivalent to the long-term support force of the pile, and insertion is started when a force greater than that acts on the pile. And when consolidation settlement etc. do not occur in the ground directly under the building, the oil pressure of the friction generating means is adjusted so that the insertion between the first insertion body and the second insertion body does not occur. . Then, when the ground directly under the building causes settlement such as consolidation under the condition that the friction generating means is adjusted in this way, the ground reaction force decreases and the load supported by the pile increases, but the reaction force When the friction force of the adjusting device is exceeded, the building sinks due to the insertion, and the ground reaction force recovers.
[0042]
The foundation structure of the present invention includes a reaction force adjusting device that causes the pile foundation to be inserted or slid when a certain amount of force is applied due to an abnormality as described above, and to reduce the applied force. Therefore, especially when subsidence such as consolidation occurs on the ground directly under the building and a force equal to or longer than the long-term support force is applied to the pile foundation, this force is reduced by the reaction force adjustment device, causing damage to the building This makes it extremely useful for earthquake countermeasures. Therefore, it becomes effective as a structural member of a particularly important building or structure.
[0043]
In addition, for buildings where the weight is uneven with respect to the foundation, the ground reaction force can be made uniform and the uneven settlement of the ground can be prevented by adjusting the arrangement of the pile foundation.
In addition, since the pile foundation and the direct foundation are used together, not only horizontal resistance but also decay attenuation to the ground occurs at the time of the earthquake, and therefore combined with the action by the reaction force adjusting device of the pile foundation, Become.
Furthermore, the number of pile foundations can be reduced to about 1/2 to 1/3 compared with the conventional pile foundation structure, and therefore, it is extremely advantageous both in terms of cost and construction period.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a basic structure of the present invention.
FIG. 2 is a perspective view of a main part showing a schematic configuration of an example of a pile foundation according to the present invention.
3 is a diagram showing a schematic configuration of the pile foundation shown in FIG. 2, wherein (a) is a cross-sectional side view of the main part, (b) is a cross-sectional view, and (c) is a front view of the main part of the insert. It is.
FIGS. 4A to 4D are side sectional views for explaining the pile foundation construction method of the present invention in the order of steps;
FIG. 5 is a graph for explaining the relationship between load and deformation in the counter-adjusting device.
FIGS. 6A and 6B are diagrams showing a schematic configuration of another example of the pile foundation of the present invention, wherein FIG. 6A is a cross-sectional side view of a main part, FIG. 6B is a cross-sectional view, and FIG. It is principal part side sectional drawing at the time of installing a part in a basic version.
FIG. 7 is a side sectional view showing an example of a conventional pile foundation structure.
FIG. 8 is a side sectional view showing an example of a conventional direct foundation structure.
FIG. 9 is a side sectional view for explaining a problem of a conventional direct foundation structure.
FIG. 10 is a side sectional view for explaining a problem of a foundation structure in which a conventional pile foundation and a direct foundation are used in combination.
[Explanation of symbols]
5 ... Ground, 10 ... Foundation structure, 11 ... Building, 12 ... Direct foundation part (direct foundation), 13, 40 ... Pile foundation, 14, 41 ... Reaction force adjustment device, 15 ... Foundation version, 16 ... Interpolated body, 17 ... Extrapolated body, 19, 45 ... Friction generating part (friction generating means), 20, 46 ... Oil accommodating part, 21, 47 ... Oil, 22, 48 ... Hydraulic adjustment valve, 23, 49 ... Membrane, 24, 50 ... Slit steel pipe, 25 ... Slit, 26 ... Thin plate part

Claims (5)

A pile foundation that is driven or embedded in the ground or in a foundation plate and further supports the building by connecting a pile head portion to the building, and is a first steel pipe insertion body connected to the building. And a second insertion body made of steel pipe that is inserted or extrapolated into the first insertion body, and one of the first insertion body and the second insertion body provided with an oil storage portion. And the wall of the oil storage portion slidably presses the other wall surface of the first insertion body and the second insertion body by the oil pressure of the oil storage portion, and these first insertion body and Ri Na reaction force adjusting device is provided that includes a friction generating means for increasing the frictional force at the time of insertion between the second insertion member, the oil receiving portion, and the steel pipe, provided in the steel pipe An annular plate, a film stuck in a state of covering the outside of the annular plate, and a slit disposed in a state of covering the film Piles characterized and the tube, in that it consists of.   The pile foundation according to claim 1, wherein a lubricant is applied to a sliding surface between the first insertion body or the second insertion body and a wall surface of the oil storage portion of the friction generating means.   The friction generating means includes an oil storage portion, oil filled in the oil storage portion, and a hydraulic pressure adjusting valve that adjusts the oil pressure in the oil storage portion, and is in contact with the wall surface of the first insertion body or the second insertion body. The pile foundation according to claim 1 or 2, wherein the wall of the oil storage portion is formed so as to be swellable by oil pressure. Wall of the oil accommodating portion is adapted from the slit steel tube in which slits are formed as easily deformed wall member, on the inner side of the wall member, to hold the liquid-tightness in the oil containing portion claim 1, 2 or 3 pile foundation according possible, characterized in that said film having elasticity is provided. It is a foundation structure that combines a direct foundation that uses ground reaction force and a pile foundation that uses support force by a pile,
A foundation structure using the pile foundation according to claim 1, 2, 3, or 4 as the pile foundation.

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