KR19990048467A - Auger pile method using expandable mortar - Google Patents

Abstract

The present invention relates to a vibration-free, low-noise pile method to increase the strength of the surrounding ground due to the expansion of the pile body and to improve the bearing capacity of the pile foundation by using the expandable mortar. The present invention by placing a hollow stem continuous flight auger on the pile foundation pour foundation and perforated to the pile target depth to form a pile body by using expandable mortar instead of concrete or mortar used in general, The purpose of the present invention is to provide an improved auger pile method that increases the bearing capacity of the pile by increasing the adhesion between the pile body and the surrounding ground. The present invention, the step of drilling the ground using a hollow continuous auger to excavate to the target depth, the step of injecting the expandable mortar to the top of the continuous auger by blending the expandable mortar on the ground, so that the perforated hollow wall is prevented from collapse And gradually drawing the continuous auger upwards while simultaneously discharging the expandable mortar from the auger tip, and arranging the head of the pile formed by the expandable mortar after removing the drawn auger from the ground.

Description

Auger pile method using expandable mortar

The present invention relates to a vibration-free, low-noise pile method to increase the strength of the surrounding ground due to the expansion of the pile body and to improve the bearing capacity of the pile foundation by using the expandable mortar.

Generally, pile foundations (deep foundations) are used to support loads of superstructures placed on soft ground and to transfer loads to solid ground. Up to now, pile foundations are constructed by driving or buying, and such a method causes many problems due to vibration and noise due to the impact during construction. In order to minimize the damage caused by vibration and noise, CFA (Continuous Flight Auger) Pile method, PIP (Packed-In-Place pile) method, MIP (Mixed-In-Place pile) method, APG ( Augered Pressure Grouted) Pile method has been developed and used.

The method shown in Figure 1 shows the sequence of the CFA pile method of the general site-pouring pile method.

In order to form the pile, hollow stem continuous flight auger is used to start the drilling of the ground. When the target depth is reached, the concrete concrete or mortar is slowly drawn at the same time through the tip of the hollow continuous auger. When the concrete or mortar injection is completed up to the upper part of the perforated part at the same time as the auger drawing, a pile structure is formed by inserting the reinforcing bar network assembled on the ground as necessary. At this time, concrete or mortar is mixed from the ground through a batch plant is provided to the upper end of the continuous auger using a hydraulic pump, concrete or mortar injected into the upper end of the auger equipment is poured into the ground through the lower end.

Compared to the existing pile pile method or the field perforated pile embedding method, such a site-pouring pile method is capable of low noise and low vibration, and may have less influence on adjacent structures. It can solve the inconvenience and speed up the work, and there are advantages in that it is possible to work in a small space (headroom), especially when reinforcing the foundation of the existing structure (eg underpinning).

However, in the field casting method, the ground is disturbed when the ground is not used, and the ground is changed to a loose state while the ground strength decreases due to the ground disturbance caused by the bit rotation of the auger tip. In addition, the ground strength deterioration phenomenon serves to reduce the overall bearing capacity of the ground. In addition, even if auger drawing is carried out simultaneously with the injection of concrete or mortar after the completion of the drilling to the target depth, it may be difficult to secure the required foundation cross-section due to insufficient slime treatment due to the collapse and decay of the disturbed soil in the empty wall. .

On the other hand, dry concrete shrinkage and thermal cracking may occur due to the temperature difference between the ground in the case of foundation concrete or mortar curing after drilling, and these phenomena reduce the adhesion between the pile structure and the ground and also the quality of the pile material itself. It will act as an element that can reduce the.

Therefore, the present invention has been made to solve the problems of the prior art as described above, it is generally used to mount a hollow stem auger (hollow stem continuous flight auger) on the pile foundation pour ground to reach the pile target depth The purpose of the present invention is to provide an improved auger pile method to increase the bearing capacity of the pile by increasing the adhesion between the pile body and the surrounding ground by using expandable mortar instead of concrete or mortar.

1 is a composition of the prior art,

2a to 2f is a construction flowchart of the inflatable auger pile method according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Placement ground 2: Continuous Auger

3: expandable mortar 4: mortar inlet

5: Auger tip 6: Rebar network

7: pile

In order to achieve the above object, the present invention, drilling a ground using a hollow continuous auger to excavate to the target depth, blending the expandable mortar from the ground and conveying the expandable mortar to the top of the continuous auger, the perforated hollow wall Slowly drawing the continuous auger upwards to prevent collapse and simultaneously discharging the expandable mortar from the auger tip, and arranging the head of the pile formed by the expandable mortar after dismantling the drawn continuous auger from the ground. It is characterized by.

The expandable mortar used in the present invention is a mortar having the required strength and expands more than the original volume, and is injected into the drilled hole under a certain pressure by using a hydraulic pump or a pump car, so that the expandable mortar is filled in the drilled hole. The loose ground will be pushed to some extent to play a role. This injection pressure increases the density of mortar, prevents the soil around the perforation hole that may be generated during continuous auger drawing, and serves to keep the contact between the pile body and the surrounding ground. In addition, the expandable mortar filled in the perforation hole expands more than the original volume during curing while maintaining the required strength, and in addition to the filling injection pressure, it is possible to expect the compacting effect by pushing the disturbed peripheral ground laterally. It will strengthen the pile's bearing capacity.

In addition, the expansion mortar is easy to secure the pile plan cross-section due to the expansion of the material, and to improve the bearing capacity by compensating to some extent by using the expandability of the injection mortar to compensate for the reduction in tip bearing capacity caused by auger bit disturbance shown in the existing method.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

2a to 2f is a construction flowchart of the expandable auger pile method according to the present invention, look at the construction sequence of the present invention with reference to the drawings as follows.

In the present invention, first, after performing the site stop operation so that the surface shape of the pile installation ground evenly, the tip 5 bit of the hollow continuous auger 2 is mounted on the placing ground 1. Then, by rotating the continuous auger (2) while excavating the disturbed soil of the perforated part to the ground (Fig. 2a), and drills the ground to the pile depth target (Fig. 2b). Through this process, upon completion of the ground drilling work using the continuous auger (2) to the target depth, the ground prepares the expandable mortar (3) having the required strength, and the prepared swellable water mortar (4) Injection into the hole inside the rod. The expandable mortar injected into the continuous auger rod hole starts to be injected into the drilled pile hole through the inner hole of the auger tip 5 (FIG. 2C), and simultaneously draws the continuous auger 2 to the ground (FIG. 2D). At this time, be careful when drawing the auger so that the already perforated pile hole does not collapse or slime remains in the hole, and also adjusts the mortar injection pressure. Thereby, the pile body 7 is formed in a perforation hole.

At the same time as the continuous auger (2) drawing, the expansion mortar injection is projected to the ground to some extent to complete the curing and to clean the head (Fig. 2e), the pile body (7) by using the reinforcing bar (6) assembled from the ground Insert before solidification to complete the inflatable auger (FIG. 2F).

The present invention carried out by the construction procedure as described above will have the following effects.

First, since the pile body is formed using the expandable mortar, the degree of close contact with the surrounding ground is enhanced, thereby improving the peripheral frictional resistance as well as the tip bearing capacity.

Second, since the expansion mortar is injected from the bottom of the auger bit to prevent material separation and to form a uniform pile body can improve the quality.

Third, since the mortar is injected at the same time as the continuous auger drawing, it is possible to prevent the fall of the pile vacant wall, and to discharge the ground slime with the auger drawing to the ground, it is easy to secure the pile cross-section.

Fourth, it is possible to use the existing equipment to ensure the economics of the construction method.

Fifth, it is possible to install in places where equipment is difficult to enter due to limited space (where it is difficult to secure head room) and can be installed with low noise and low vibration.

Sixth, the pile length can be adjusted freely and continuous construction is possible. In particular, in the case of large depth piles, it is possible to prevent the reduction of pile bearing capacity due to the joints.

Claims (2)

The first step of drilling the ground using a hollow continuous auger to excavate to the target depth, the second step of blending the expandable mortar from the ground to press the expandable mortar to the top of the continuous auger and to prevent the perforated hollow wall to collapse And a third step of slowly drawing the continuous auger upwards and simultaneously discharging the expandable mortar from the auger tip to form a pile body with expandable mortar in the perforations. The method of claim 1, further comprising a fourth step of arranging the head of the pile body formed by the expandable mortar after removing the drawn continuous auger from the ground, and a fifth step of inserting the pile body into the pile body before the pile body is solidified. Auger pile method, characterized in that it comprises.