JPS649413B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for increasing the bearing capacity of soil using water-absorbing and expanding concrete that has the property of expanding when it absorbs water.

[Prior Art] Conventionally, known methods for increasing soil bearing capacity include driving existing piles, pine logs, steel pipes, concrete piles, etc., and hardening the soil layer with a hardening agent such as cement.

[Problems to be Solved by the Invention] However, the conventional methods described above have problems in that the equipment costs and construction costs are high, and the workability is also poor.

An object of the present invention is to provide a method for increasing the bearing capacity of soil using water-absorbing and expanding concrete, which attempts to solve the above-mentioned problems.

[Means for Solving the Problems] The present invention includes forming a reinforcing body by fixing one or more steel bars to a bottom plate provided with an upwardly curved concave portion in the shape of a bowl. into a construction hole drilled in the construction ground with a diameter that allows the bottom plate to be inserted, lower the bottom plate downward, and fill the construction hole with water-absorbing and expanding concrete. A cover plate with a bowl-shaped concave portion curved backwards and downwards is passed through the upper part of the steel bar through a hole to tightly adhere to the water-absorbing and expanding concrete, and then the steel bar and cover plate are welded and fixed together. The above problem was solved by adopting this method.

[Operation] According to the method of the present invention having the above configuration, the water-absorbing and expanding concrete filled in the upper part of the bottom plate of the reinforcing body installed in the construction hole is positioned so as to match the intended planned height of the construction hole. By determining and fixing the cover plate to the steel bar, the cover plate and bottom plate will be pressed from above and below, so expansion in the vertical direction will be suppressed, and the water-absorbing expandable concrete will only flow in the circumferential direction of the construction hole. expands, increasing the frictional resistance against the surrounding soil and at the same time extremely lowering the water content ratio of the surrounding soil, which increases the bearing capacity of the soil.

[Example] An example of the method of the present invention will be described in detail with reference to the drawings. The bottom of one or more steel bars 3 is welded and fixed to a bottom plate 2 provided with a concave portion 1 curved upward into a bowl shape. A reinforcing body 4 is formed. Then, in the construction ground whose bearing capacity is to be increased, a construction hole 5 is bored by drilling, pressure drilling, or the like. The working hole 5 must be formed to have a diameter that allows the bottom plate 2 of the reinforcing body 4 to be inserted therein, and the steel bar 3 must be longer than the depth of the working hole 5.

As shown in FIG. 1, the reinforcing body 4 is lowered into the drilled construction hole 5 with the bottom plate 2 facing downward. Filling concrete 6 into the construction hole 5 to a predetermined height,
After that, a through hole 7 is drilled through the upper part of the steel bar 3, and a cover plate 9 formed by providing a concave portion 8 curved downward into a bowl shape is attached to the water absorbing material that has been filled into the hole 5. The steel bar 3 is tightly covered on the expandable concrete 6, and the steel bar 3 is inserted into the through hole 7 and the contact surfaces are welded to fix the steel bar 3 and the cover plate 9 together.

Further, as shown in FIG. 2, the steel bars 3 protruding above the ground surface are welded and fixed together with the reinforcing bars 11 of the upper structure 10 such as the foundation bottom slab, thereby reinforcing the upper structure 10. I'll do what I do. In addition, the water-absorbing and expanding concrete 6 filled in the construction hole 5 absorbs water in the surrounding soil and expands, but at this time, a phenomenon occurs in which the water content ratio of the surrounding soil is extremely lowered, and at the same time Since the cover plate 9 and the bottom plate 2 are provided and pressed,
The direction of expansion is limited only to the circumferential direction of the construction hole 5, and therefore strong frictional resistance is generated against the surrounding soil in the circumferential direction, making it possible to obtain the desired soil bearing capacity.

[Effects of the Invention] Since the present invention is as described above, the water-absorbing and expanding concrete filled in the construction hole expands only in the circumferential direction of the construction hole, creating a large frictional resistance against the surrounding soil. The combination of the above-mentioned water-absorbing expandable concrete and the reinforcing steel bar provides sufficient soil bearing capacity to soft ground. For example, the method of the present invention can be applied to the ground that lacks soil bearing capacity in general buildings, etc., to achieve its effect. Moreover, the method of the present invention is easy to work with, so the construction time is shortened, leading to lower construction costs.

[Brief explanation of the drawing]

The drawings show an embodiment of the method of the present invention, and FIG. 1 is a longitudinal sectional view, and FIG. 2 is a longitudinal sectional view showing the state after the same construction. In the figure, 1 is a recess, 2 is a bottom plate, 3 is a steel bar, 4 is a reinforcement body, 5 is a construction hole, 6 is water-absorbing expandable concrete, 7 is a through hole, 8 is a recess, and 9 is a cover plate.

[Claims]

1. When removing the tensile materials from the anchor body created by arranging a temporary burial body with a plurality of tensile materials tied around it in the center of a hole dug in the ground and pouring a hardening material, The temporary buried body is removed to form a cavity in the center, a pull-out guide rod is inserted into this cavity, each tensile material is wound around the pull-out guide rod as a core, and while being twisted, it is peeled off from the anchor body and removed. A tensile material removal method characterized by sequentially applying this to all tensile materials and removing them.