JPH0355611B2 - - 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. is lowered with the bottom plate downward into a construction hole drilled in the construction ground with a diameter that allows the bottom plate to be inserted, and the bottom layer of water-absorbing and expansive concrete is placed in the construction hole, A non-expandable material is then laminated on top of the non-expandable material, which is then alternately filled and laminated in several stages.After that, a cover plate with a concave portion curved downward into a bowl shape is inserted into the top of the steel bar through a through hole. The above-mentioned problem was solved by making the steel bar penetrate through the concrete to adhere to the top layer of water-absorbing expandable concrete, and then welding the steel bar and the cover plate together to fix them together.

[Operation] According to the method of the present invention having the above-mentioned configuration, the water-absorbing and expanding concrete packed and laminated together with the non-expandable material on the top of the bottom plate of the reinforcing member installed in the construction hole reaches the intended planned height of the construction hole. By determining the position and fixing the cover plate to the steel bar, the cover plate and bottom plate will press from above and below, suppressing expansion in the vertical direction and only expanding in the circumferential direction of the hole. The water-absorbing expandable concrete expands and forms a continuous uneven shape throughout, increasing the frictional resistance against the surrounding soil and at the same time extremely lowering the water content ratio of the surrounding soil, which causes the soil to become resistant to soil. It will increase your power.

[Example] An example of the method of the present invention will be described in detail with reference to the drawings. The bottom part 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. Concrete 6 is the lowest layer, and on top of that, non-expandable bodies 12 made of ready-made concrete, cylindrical bodies made of iron pipes, or general aggregates such as sand, gravel, etc. are laminated, and thereafter these are alternately stacked in several stages. Then, the steel bar 3 is filled and laminated to a predetermined height in the construction hole 5, and then a through hole 7 is drilled through which the upper part of the steel bar 3 is inserted, and a concave portion 8 curved downward into a bowl shape is formed. The cover plate 9 is tightly covered with the uppermost layer of water-absorbing and expanding concrete 6 that has been filled into the construction hole 5, and the steel bar 3 is placed in the through-hole 7.
The steel bar 3 and the cover plate 9 are connected by penetrating the steel bar 3 and welding their contact surfaces.
and are fixed together.

Furthermore, 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 plate, thereby reinforcing the upper structure 10. I'll do what I do. In addition, the layer of water-absorbing expandable concrete 6 filled in the construction hole 5 and the non-expanding body 12 are such that only the water-absorbing expandable concrete 6 absorbs moisture in the surrounding soil and expands; A phenomenon occurs in which the water content ratio of the soil is extremely lowered, and since the cover plate 9 and the bottom plate 2 are provided on the upper and lower sides and are pressed, the direction of expansion is limited to only the circumferential direction of the construction hole 5. The soil expands and forms a continuous uneven shape as a whole, which creates strong frictional resistance 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 in combination with the non-expandable material expands only in the circumferential direction of the construction hole, resulting in a continuous uneven shape as a whole. This creates a large frictional resistance against the surrounding soil, and the combination of the above-mentioned water-swelling concrete and the reinforcing steel bars provides sufficient soil bearing capacity to soft ground. The method of the present invention is fully effective when used on ground that lacks bearing capacity in construction, and since the method of the present invention is easy to work with, the construction time is shortened, leading to lower construction costs.

[Brief explanation of drawings]

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, 9 is a cover plate, and 12 is a non-expandable It is the body.

Claims (1)

[Claims] 1. A reinforcing body is formed by fixing one or more steel bars to a bottom plate provided with an upwardly curved concave portion in the shape of a bowl, and the diameter of the reinforcing body is such that the bottom plate can be inserted into the construction ground. At the same time, the bottom plate is lowered and lowered into the construction hole that has been drilled, and water-absorbing and expanding concrete is placed as the lowest layer in the construction hole, and a non-expanding material is laminated on top of that. are alternately filled and laminated in several stages, and then a cover plate with a concave portion curved downward in the shape of an arm is passed through the upper part of the steel bar through a through hole to form the top layer of water-absorbing and expanding concrete. A method for reinforcing the bearing capacity of soil using water-absorbing and expanding concrete, which is characterized by adhering closely and further welding a steel bar and a cover plate to fix them together.