JPS6044450B2 - Deep compaction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a compact which is formed by attaching several pressing plates to the lower end of a steel rod so that they can be opened and closed in a manner that opens in a substantially circular plane and has a pointed tip. The device is filled with filler such as gravel, sand, or chemicolime and then driven into the specified ground, and when it reaches a predetermined depth, the device is pulled up to create a column of filler in the ground, and then the A deep compaction machine characterized by strongly compacting the ground around the pile together with the filler column by driving knotted piles into the filler column while replenishing the circumference of the pile with sand, gravel, etc. Regarding the law.

Among the foundation piles currently in use, there are piles with adjustable positions, such as triangular piles and hexagonal piles, which have several joints P' attached at appropriate intervals to the pile body P, as shown in Figure 5. When constructing a knotted pile as the foundation of a structure, it is generally used as a friction pile in view of its bearing capacity and properties. The conventional construction method was to pour filler such as gravel or sand from the surrounding area of the pile on the ground and compact the ground around the pile while driving the pile.

However, in this known method, the filling material B is placed in the gap between the pile and the ground surrounding the pile, which is created by the joints that descend as the pile sinks.
Since this is a construction method that simply press-fits the material around the pile pillars at the joints of the pile while injecting it from the ground, filler B must be placed sufficiently below the pile, that is, deep into the tip of the pile, as shown in Figure 5. It is extremely difficult to carry out filling, and therefore filling has only been carried out in a part of the area around the ground.Therefore, the above-mentioned known method cannot sufficiently compact the ground around the pile. However, there are serious drawbacks in that it is impossible to increase the pile bearing capacity, and stable pile bearing capacity cannot be expected at all in the ground that is soft near the tip of the pile and requires compaction improvement.

The present invention focuses on these drawbacks and uses a device with an extremely simple structure to sufficiently distribute filler such as sand and gravel deep into the tip of the pile, thereby ensuring reliable filling over a wide area of the ground surrounding the pile. The present invention aims to provide a deep compaction method which is capable of producing a compaction effect and greatly increasing the pile supporting capacity.

The construction method of the present invention will be explained below.

First, the structure of the device used in the construction method of the present invention will be explained in detail with reference to illustrative drawings. An I-type, H-type, etc. steel rod 1 is used as a support, and the lower tip edges of both flanges 1'', 1'' of the steel rod 1 are held constant. The inclined cut surfaces 1'', 1'' are formed to have a pointed shape, and the pressing plates 2, 2 are attached to the tip of the pointed angle via the support shaft 3 to the web 1''''.
The pressure plates 2, 2 are arranged in parallel at the lower part of the flanges 1'' and are attached so as to be rotatable to close and open. Also, during pouring, the pressing plates 2, 2 are pressed against the downwardly inclined cut surface 1 of the flanges 1'', 1'' due to earth pressure resistance, etc. ``, 1'', and therefore the pressing plates 2, 2 have a sharply pointed shape with the support shaft 3 as the apex angle).

At the same time, the pressing plates 2, 2 have a substantially circular shape in plan view. In addition, several support shafts 3 are provided below the steel rod 1 with their angular positions tilted, and several press plates 2 are attached to these so that they can be opened and closed to make the tip part more secure. It may also be formed into a pointed shape. In addition, as another implementation structure, as shown in FIG. 4, the lower part of the flanges 1'', 1'' of the steel rod 1 is not formed into a pointed inclined surface, and the pressing plates 2, 2 are attached to the lower part of the plate-shaped steel rod 1 on the support shaft 3. It is one idea to attach the pressure plates 2, 2 so that they can be opened and closed freely through the wafer 1"", but in such a case, the pressure plates 2, 2 should be attached to both sides of the wave 1"" in order to maintain a constant pointed shape at all times. Provide a backing plate 4 of appropriate length or flange 1
The structure is such that the lower corner edge of 1" and 1" directly acts as a stopper.

Next, to explain the case where the construction method of the present invention is implemented using the above-mentioned device, first, the upper part of the compact device is fixed with a vibrator W such as a pipe hammer, or is directly struck with a hammer. Drive into the joint pile driving point.

(Fig. 6) Following this driving, the press plate 2 at the tip of the device
. . . opens into a substantially circular plane and has a pointed shape,
A hole A with a circular cross section is created in the ground by penetrating the pointed part 2'', and a filler B such as gravel, sand, chemicolime, etc. is poured into the hole A at the same time as the drilling operation. However, the charging material B is filled deep into the ground by the press-fitting action of the pressing plates 2. In particular, the filling material is pushed into the surrounding ground by the driving vibrations, etc. The area will be preliminarily compacted.

(Figure 7) When the driving of the Compact device and the filler such as gravel, sand, chemicolime, etc. reach a predetermined depth at the pile driving point, the Compact device is removed.
Since the pressing plates 2... are rotatably supported at the tip of the steel rod 1, the pressing plates 2, 2 can be moved by simply pulling the steel rod 1 upwards. The weight of B,
Due to the action of the surrounding soil, etc., it automatically hangs downward into a plate shape (Fig. 8) and becomes approximately the same diameter as the driving body, so that the steel rod 1 is free from any resistance damage. , it can be carried out on the ground very easily.

In this way, by pulling up the device, the hole A of the pulled-up remaining hole is
Inside, it is possible to easily create a filler column C using a filler B such as gravel, sand, or chemicolime.

(Fig. 9) Next, so-called knotted piles P such as triangular piles and hexagonal pits are built into the filler column C of the filler B, such as gravel, sand, and chemicolime, which can be created underground, and when these are driven. , Sand, gravel, etc. are added from the ground to the gaps around the pile due to the penetration of the joints, and the gravel of the filler column C that has already been driven is removed. , sand, chemicolime, etc. filler B is applied to each joint P'' of the jointed pile P.
This will ensure that the ground around the pile is compacted firmly, and the ground around the pile will be further compacted by the supplementary filling material around the pile, and the ground will be further compacted to the deep part of the pile. It is also possible to construct foundation piles using friction piles that can be sufficiently filled with filler B such as gravel, sand, and chemicolime.

(Fig. 10) As described above, the present invention is a very simple device in which a pressing plate 2 is supported under a steel rod 1 so as to be rotatable in opening and closing to form a pointed shape. By filling the filler at the same time as driving, primary compaction is performed by the driving vibration, etc., and secondary compaction is performed when the joint pile is driven, so the amount of filler filled into the ground can be reduced. As a result, the soil improvement effect is also remarkable, such as the ability to obtain an outstanding and stable pile bearing capacity compared to conventional construction methods.

Moreover, since the press plate of the device opens into a substantially circular plane, a column of filler material with a substantially circular cross section is created, so when a knotted pile is driven, the filler material is spread almost evenly around the pile. As a result, foundation piles with uniform bearing capacity can be obtained. Furthermore, the present invention allows the filler to be reliably filled deep into the pile, increasing the compact effect and increasing the pile bearing capacity.In particular, since the filler is filled in a wider area than the pile core, it is possible to prevent sand from being deposited during an earthquake. This is the most suitable method for improving ground with good fluidity.

In addition, when there is a soft ground layer D etc. that requires improvement at a considerable depth in the ground, the lengths of the filler columns C and the knotted piles P do not necessarily match, and even in such a case, the filler columns are fixed as shown in Figure 11. It is natural that sufficient consolidation and dewatering effects can be expected by driving only C up to the soft ground layer D, and therefore, it is necessary to use knotted piles P that are shorter than the filler columns. It is clear that there is no difference in the effect.

In addition, since the above method uses a simple device in which a pressing plate 2 is simply provided at the tip of a steel rod 1, the filler B such as gravel is used as in the conventional method.
It can be said that it is an extremely economical construction method because it is possible to reliably place the filler into the ground without requiring a small amount of casing, etc., which are used when filling the ground.

Furthermore, the present invention makes it possible to pre-drill all the required number of filler columns depending on the circumstances at the site, and then sequentially drive knotted piles P into the cast filler columns. In addition, when such a construction method is used, it also has the effect of greatly reducing the construction efficiency.

[Brief explanation of the drawing]

Fig. 1 is an overall view of the compaction construction device according to the present invention, Fig. 2 is a cross-sectional plan view of the same, Fig. 3 is a vertical cross-sectional side view of the same,
Fig. 4 is an embodiment diagram showing another implementation structure, Fig. 5 is a drawing of a knotted pile driven by conventional Compact construction, Fig. 6,
Figures 7, 8, and 9 are schematic diagrams sequentially showing the construction state of the present invention, Figure 10 is a diagram of the completed construction, and Figure 11 is the construction state when the improved ground is located deep underground. This is a body diagram. Explanation of symbols: 1... Steel rod, 2... Pressing plate, 3... Support shaft, 4... Backing plate, A.
...Vacancy, B...Filling, C...
・Filling material column, D... Soft ground, P...
Knot pile, P''... Same as above joint part, W... Hammer.

Claims (1)

[Claims] 1. A compact device consisting of several pressing plates attached to the lower end of a steel rod so as to be rotatable in opening and closing so that the planar surface is approximately circular and the lower tip forms a pointed part is attached to the lower end of a steel rod. , filled with filler such as Chemicolime, and then driven into the specified ground.
When this reaches a predetermined depth, the device is pulled up to create a filler column in the ground, and then a knotted pile is driven into the filler column while replenishing the circumference of the pile with sand, gravel, etc. A deep compaction construction method characterized by strongly compacting the ground around the pile together with the filler column.