JPH0144852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a structure foundation, in which a foundation pile 1 is driven into a predetermined position, gravel 2 is then laid on top of the foundation pile 1, and then a footing is placed on the two layers of gravel. The present invention relates to a method for constructing a structure foundation, which is characterized in that the structure foundation is constructed in a state in which the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state in which the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state where the foundation of the structure is constructed in a state where the foundation of the structure is constructed without being connected to the pile 1.

When constructing the foundation of a conventional structure, the so-called
Except for the "solid foundation", whether it is a cloth foundation or an independent foundation, the foundation pile is driven into the specified ground, and the footing of the above-mentioned cloth foundation, independent foundation, etc. is connected to the top of the foundation pile. The upper end of the reinforcing bar embedded in the foundation pile is removed, the upper end of the reinforcing bar is connected to the reinforcing bar for the footing, and then concrete is poured to build the footing. The usual method was to construct a structure and support the structural load with foundation piles. However, in the case of the above conventional method, if lateral force is applied to the structure due to an earthquake, etc., the foundation pile connected to the footing,
In particular, horizontal force and rotational force act on the upper part of the foundation pile, and there is a risk that the pile body will be damaged by the tensile force and shearing force caused by the bending moment. Since the force increases approximately in proportion to the force, in order to prevent the above-mentioned damage, it is necessary to greatly improve the horizontal strength of the foundation pile, which has the disadvantage that it is not economical as a foundation construction method.

The present invention was invented in view of the above points, and its purpose is to prevent the foundation piles that support the weight of the structure from being connected to the footings, so that even if lateral force acts during an earthquake, the foundation piles will not be connected to the footings. horizontal force and rotational force are not transmitted, and no tensile stress or shear force is generated on the foundation pile, so only compressive stress needs to be considered for the foundation pile, and a foundation pile that can only withstand vertical loads is sufficient. Therefore, it is an object of the present invention to provide a method for constructing a structure foundation that can greatly improve economic efficiency and prevent foundation piles from being destroyed during an earthquake.

The present invention will be explained in detail below with reference to Examples. First, a plurality of foundation piles 1 are driven into predetermined positions below the footing 3 to be constructed. In the illustrated embodiment, a knotted pile having a plurality of knotted parts 4 on the upper and lower outer peripheries is used as the foundation pile 1. When a knot pile is used as the foundation pile 1 in this way, when the foundation pile 1 is driven, the foundation pile 1
It will be better if gravel 2 is filled between the piles (the joint piles are driven while supplementing gravel from the ground into the gap between the piles and the ground 5 that is created due to the penetration of the joint piles). The top surface of the foundation pile 1 is preferably about 0.2M to 0.5M higher than the bottom surface of the footing 3 to be constructed. Next, gravel 2 is laid on the top of the foundation pile 1 in the area below the footing 3 to be constructed, and compacted with a weight or the like. At this time, the thickness of gravel 2 is 0.2M ~
It should be about 1.0M. Here the top of the pile is footing 3
If it is close to the bottom surface, the ground 5 will be excavated to the bottom of the knot 4 located above, and gravel 2 will be laid down, as shown in FIG. A slippery waterproof sheet 6 such as a synthetic resin sheet is laid on the upper surface of the second layer of gravel, then a formwork 7 is temporarily installed, reinforcing bars 8, etc. are placed, ready-mixed concrete is poured into the formwork 7, After the concrete hardens, the formwork 7 is removed, and the gap is filled with earth and sand to construct the footing 3. After the footing 3 is constructed, the reinforcing bars of the columns, walls, etc. of the superstructure are connected to the reinforcing bars within the footing 3 to construct the structure. In the above embodiment, an example of a joint pile is shown as the foundation pile 1, but it is needless to say that the foundation pile 1 is not limited to this, and piles of various values can be used.

In addition, if you build a footing by laying a slippery waterproof sheet on the gravel layer and pouring fresh concrete on top of it as in the example, the fresh concrete will not soak into the gravel layer and harden the gravel layer, and the foundation The piles and footings are kept in a disconnected state, and when lateral force is applied to the structure during an earthquake, the slippery waterproof sheet improves the slippage of the underside of the footing after construction, and prevents interference with the roller action of gravel grains. horizontal force and rotational force are not transmitted to the foundation pile.

In the present invention, as described above, gravel is spread over the top of the foundation pile, and then the footing is built on this gravel layer in a discontinuous manner with respect to the foundation pile, so the foundation pile covers the bottom surface of the footing and the gravel layer. It supports only the vertical load P (the structure's own weight) transmitted through the foundation pile, and when lateral force acts on the structure during an earthquake, etc., the foundation pile receives horizontal force H and rotational force M due to the roller action of gravel grains. is not transmitted, and therefore no tensile stress or shear stress is generated in the foundation pile. Therefore, in the case of the present invention, only compressive stress needs to be considered for the foundation pile, and a foundation pile that can only withstand vertical loads is sufficient, making it possible to greatly improve economic efficiency compared to the conventional method. It is possible to construct a sufficiently safe structure without destroying the foundation piles. Furthermore, when knot piles are used as foundation piles and a gravel layer is provided to the bottom of the upper knots, the load is transferred by the penetration of the knots compared to when the structure load is transmitted to the ground and foundation piles using only the gravel layer. In particular, the load can be transmitted more effectively to the foundation piles. By the way, it is already known that gravel columns are effective in preventing liquefaction of sandy ground (in which the pore water pressure in the ground increases and the ground loses its bearing capacity), but as shown in the example, it is not necessary to fill it between the foundation piles. The gravel wall connected to the upper gravel layer prevents the rise in pore water pressure (the gravel layer acts as a drainage layer), preventing liquefaction and, in other words, preventing damage to structures caused by earthquakes. It can be prevented.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of one embodiment of a building foundation constructed by the method of the present invention, Fig. 2 is a cross-sectional view of the same formwork temporarily installed, and Fig. 3 is a cross-sectional view of a building foundation constructed by the present invention. 1 is a cross-sectional view of another embodiment;
is the foundation pile, 2 is the gravel, and 3 is the footing.

Claims (1)

[Claims] 1. The method is characterized in that a foundation pile is driven into a predetermined position, gravel is then laid on top of the foundation pile, and then a footing is constructed on the gravel layer in a state that it is not connected to the foundation pile. A method of constructing foundations for structures. 2. A method for constructing a structure foundation according to claim 1, characterized in that a knotted pile having knots on the outer periphery is used as the foundation pile.