JPS6023211B2 - Embedded pile construction method and its equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to construction of foundation piles for structures and buildings, and an apparatus therefor.

In recent years, the construction of foundation piles in urban areas has been prohibited due to noise and vibration, and the driving method is prohibited because it causes pollution, and the buried method has been used instead.

However, the biggest disadvantage of this embedding construction method is that the supporting capacity of the pile is weak, and the initial settlement after embedding is particularly large. Conventionally, in order to solve this problem, concrete was poured into the bottom of the hole dug with an auger, and the pile was lowered from above, but the cross-sectional area formed by the concrete was the area of the bottom of the pile. Not only was it not very effective in increasing the bearing capacity, it also required a large amount of concrete, which was extremely uneconomical. The present invention relates to an improvement of such a known embedment construction method, and is intended to reduce the amount of consolidation material used and increase the supporting capacity of the constructed pile.

This invention has a screw auger that has an enlarged blade that extends outward when reversed at the tip, and an Enoki earth screw is installed on the rotating hollow shaft above this through a section where there is no earth removal screw. First, we excavated a hole with an inner diameter slightly larger than the outer diameter of the pile to be buried while rotating the screw auger in the normal direction until it reached the supporting layer from the ground surface. After that, the screw auger is rotated in the reverse direction to extend the enlarged blade, and when the screw auger is rotated in the forward direction, the auger is moved up and down through the inner wall of the hole provided in the middle of the excavated support layer or in the upper layer of the support layer that is in contact with it. Then, the hole was excavated to be enlarged without any damage, and then, using a hollow auger, a sand machine was applied to the enlarged part of the hole while injecting solidification material into the hole. After mixing the solidifying material with L
The auger is rotated in the normal direction, the enlarged blade is closed and pulled out, the pile is immediately inserted, and the tip of the pile is press-fitted into the consolidation material and sandy rock mixing part in a static manner to solidify. This is a drilled pile construction method.

The second invention is that an auger head is installed at the bottom of the screw part consisting of a hollow shaft through a hollow ball having no screw at all, and this auger head also has a
Equipped with a digging blade having an outer diameter equal to or smaller than the outer diameter of the screw that performs an excavating action when rotating in the forward direction, and an enlarged blade that extends outward from the outer diameter of the screw and performs an excavating action when rotating in the reverse direction. This is an embedded pile construction device characterized in that the auger head is provided with a consolidating material spout that extends through the hollow shaft at the top of the auger head.

The invention of an apparatus for carrying out the method of the invention will now be described by means of representative embodiments shown.

In the figure, the Kamegawa screw auger is shown, and its driving part is generally slidably mounted on a leader 12 supported on a crawler-type running vehicle 11 in the vertical direction, and a hollow shaft 13 in the vertical direction. A screw turtle 4 for Hi± is fixed around it, and the lower end of this hollow shaft 3 has a 0.7 to 2.0 screw.
A hollow shaft 15 with a skin length and no screw is connected to it, and an auger head 16 is installed at the lower end. However, the length of the hollow width 15 is not limited to this range, but may be changed depending on the dimensions of the pile to be constructed, and it is usually economical to set it within this range from the viewpoint of constructing the pile. A drilling blade 17 having a lead angle in the same direction as the screw 14 and smaller than the outer diameter of the screw 14 is fixed to the auger head 16, and when the auger head 16 is rotated in the reverse direction, the hole inner wall and It is also equipped with an enlarged blade 18 that protrudes beyond the outer diameter of the screw 14 due to the friction of
There may be no lead angle at all. In the actual drawing, one end of the enlarged blade 18 is pivotally supported on a part of the steel part 19 of the auger head, and when rotating in the forward direction, the tip of the enlarged blade 18 moves toward the shaft part 19, and when rotating in the opposite direction, At the same time, it expands outward. A consolidating material spout 20 suitable for the hollow shafts 13 and 15 is provided on the peripheral surface and lower end surface of the shaft portion 19 of the auger head 16. In order to embed a pile using the apparatus of the present invention configured as described above, first, the screw auger 10 guided by the T-reader is set up on the ground surface and is driven to remove the pile to be embedded. Hole 2 slightly larger than the diameter
1, and the earth and sand excavated by the 9E earth screw 14 is poured from the upper end of the hole 21.

When the lower end of the auger head 16 of the screw 10 reaches the supporting layer (usually rocky shore layer or sandy rock layer) 22, all the earth and sand in the screw 14 portion is discharged to the outside ~ Screw Auger IQ rotate in the forward direction.

Next, when the screw auger turtle Q is rotated in the opposite direction, the enlarged blade 8 will extend further outward than the outer diameter of the screw i4 due to friction with the hole 23, as shown in FIG. 3, and excavate the inner wall of the hole 21. and the support layer 22 or the layer 23 in contact therewith.
Excavate the part to a large diameter.

While moving the entire screw auger 10 up and down by 1 degree, inject cement milk into the caking agent using the hollow parts of the hollow balls 13 and 5, and pour the caking agent through the spout 20. While squirting the sand into the excavated sand machine, the screw auger Q is rotated in the opposite direction and moved up and down to mix the solidifying agent and the sand collar. 18 and remove the screw auger 1 fin from the hole 21. Next, remove the screw auger 1 fin from the hole 21.
4 is inserted into the hole 21, and the lower end of the pile 24 is press-fitted into the mixed part of the consolidation material and sandy rock, and the consolidation material is solidified in the "as-is" state.

As mentioned above, in the apparatus of the present invention, between the lower end of the screw 14 and the auger head 16, there is a hollow shaft 15 portion without any screw 14, so that when excavating by rotating the screw auger 10 in the forward direction, ``Below this hollow shaft section 15, excavated soil, sand, dirt, etc. are simply destroyed and are not discharged.

Therefore, even if the auger head 16 reaches the support layer 22 or penetrates into the support layer, the sand in this area will not be discharged to the outside, and the excavator's sand above the screw 14 will be discharged to the outside. This part of the sand machine can be used as is as aggregate for binding material, and when the screw auger is rotated in the opposite direction, a hole with a large inner diameter can be formed by the extension of the enlarged blade. In this case, since the screw 14 rotates in the opposite direction, there is no scarring effect at all, and when mixing with the consolidation material, the lead angle of this screw 14 causes
This prevents the mixture of consolidation material and sandy rock from floating, creating the effect of compaction. Furthermore, the apparatus of the present invention has the advantage that piles can be constructed using the method described above.

Further, in the method of the present invention, in the supporting layer 22 or the layer 23 connected thereto, the enlarged blade 18 is used to form the hole 21.
The inner wall of the rock can be excavated to make it have a larger inner diameter, and the sandy rock in this area can be used as is for the consolidation material, so the amount of consolidation material used can be reduced accordingly. Furthermore, since the fly frame is mechanical, it can be made reliably, and the solidified material and the sand-edge mixture can be reliably formed into a cylindrical shape larger than the outside diameter of the pile 24 by the vertical movement of the auger 10, and when solidified, the pile 24 Lower end and support layer 21
It becomes a cylindrical concrete unit that is integrated with the concrete. Furthermore, with this method and device, by making some improvements to the known screw auger, it is possible to carry out a method with a marked difference, and it is extremely practical, and is the same as the conventionally known embedding method. To obtain the bearing capacity, the number of piles can be reduced by about 20 to 40%. If the support layer 22 is a layer of clay with little sand or rock, for example, use the hollow shafts 13 and 15 to inject mortar mixed with fine sand, or use the screw 14 to add sand or gravel. etc., into the hole 21.

In addition, if the expanded trench part is in the support layer, the pile 24
and the support layer 22 have the effect of being completely integrated and solidified.

Furthermore, even when the expanded trench portion is in the upper layer of the support layer in contact with the support layer, the concrete made of a mixture of sand rock and consolidation material will definitely form a bulbous shape at the lower end of the pile 24 and will form on the support layer 22. Therefore, sufficient supporting force can be obtained.

In addition, the depth at which the sand edge is not discharged varies with the length of the hollow shaft 15, and when this is used, the length of the bulb-shaped concrete can be approximately the same as this, making it strong.

Brief description of the drawings The drawings relate to this invention,
Fig. 1 is a schematic external view of the device of the present invention, Fig. 2 is a side view of the tip of the screw auger when the screw auger is rotating in the forward direction for excavation, Fig. 3 is a side view of the tip of the screw auger when the screw auger is rotating in the reverse direction for excavation, and Fig. 4 is a side view of the tip when the screw auger is rotating in the reverse direction.
The figure is a vertical cross-sectional side view showing the state of connection between the tip of the pile and the support layer after the pile is embedded, and FIGS. 5 and 6 are schematic cross-sectional plan views of the opening/closing mechanism of the enlarged blade.

Code in the figure 10...Screw auger, 13...
...Hollow shaft, 14...Screw, 15...
...Hollow shaft, 16...Auger head, 17...
Drilling blade, 18... Enlarged blade, 20... Consolidation material injection port, 21... Hole, 22... Support layer. Figure 6 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. It has an enlarged blade that protrudes outward when reversed at the tip, and an earth removal screw is provided on the rotating hollow shaft above this through a section where no earth removal screw is provided. With a screw auger, first from the surface until it reaches the supporting layer,
Excavate a hole with an inner diameter slightly larger than the outside diameter of the pile to be buried while rotating the screw auger in the forward direction, and after removing the soil from the screw section, rotate the screw auger in the reverse direction. , the enlarged blade is extended, and the auger is moved up and down to excavate the inner wall of the hole provided in the middle of the excavated support layer or in the upper layer of the support layer in contact with the excavated support layer during normal rotation, without discharging the soil. The hole is enlarged by cutting and stirring, and then using the hollow shaft of the auger, the consolidating material is injected into the hole while stirring and mixing the gravel and the consolidating material in the enlarged part. Embedded pile construction characterized by rotating the auger in the forward direction, closing the enlarged blade, pulling it out, immediately inserting the pile, and press-fitting the tip of the pile into the consolidation material and sand and gravel mixed area under static pressure to consolidate it. Law. 2 At the lower end of the screw auger part consisting of a hollow shaft,
An auger head is installed through a hollow shaft without any screw, and this auger head has a digging blade with an outer diameter equal to or less than the outer diameter of the screw, which performs a digging action during forward rotation. The auger head is equipped with an enlarged blade that protrudes outward from the outer diameter of the screw and performs a digging action during reverse rotation, and the shaft of the auger head is equipped with a solidifying material jet that communicates with the hollow shaft at the top. An embedded pile construction device characterized by having an exit.