JP2003147766A - Burying method for steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit sufficient bearing power by smooth work when burying a steel pipe pile for arranging a spiral blade on the tip. SOLUTION: When burying the steel pipe pile 5 for arranging the spiral blade 6 on the tip, an excavation hole 4 is preformed by excavating the ground 2 of a position for burying the steel pipe pile 5 up to the front of a support layer 3, and afterwards, the steel pipe pile 5 is rotatably buried up to the excavation hole 4, and then, the spiral blade 6 arranged on the tip is intruded in the support layer 3.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of embedding a steel pipe pile capable of exhibiting a high supporting force by penetrating a blade provided at a tip thereof into a support layer. is there. 2. Description of the Related Art When constructing a building, a foundation is sometimes constructed by embedding a steel pipe pile having a spiral blade at the tip. Embedding steel pipe piles in gravel ground where it is difficult to directly embed by rotating a steel pipe pile with a spiral blade at the tip, or in clay ground where it is difficult to rotate and directly embed the steel pipe pile with large adhesive strength In this case, after excavating the ground to a predetermined depth including the supporting layer by a spiral auger or the like in advance at the position where the steel pipe pile should be buried, the steel pipe pile is rotated to the excavation part and adjusted to the depth of the excavation part. It is common to bury it by doing. Further, as disclosed in, for example, JP-A-8-319616, a bulge may be formed in a support layer around a tip portion of a steel pipe pile. [0004] As described above, in the technique of digging a position where a steel pipe pile is to be buried including a support layer and then rotating and burying the steel pipe pile in the excavated portion, the support layer is excavated. Since the ground is loosened, it is necessary to inject and harden cement milk into a support layer made of loose ground around the tip of the steel pipe pile, which causes a problem that the operation is complicated and complicated. It is an object of the present invention to provide a method of burying a steel pipe pile capable of performing a smooth operation and exhibiting a sufficient supporting force. [0006] In order to solve the above problems, a method of burying a steel pipe pile according to the present invention is a method of burying a steel pipe pile having a spiral blade at a tip thereof. Drilling before the support layer at the position where the steel pipe pile should be buried,
Thereafter, the steel pipe pile is rotatably buried up to the excavation site, and the spiral blade provided at the tip is penetrated into the support layer. In the method for burying a steel pipe pile, a position where the steel pipe pile is to be buried is excavated in advance to the front of the support layer, and when the steel pipe pile is buried, the steel pipe pile is rotated to penetrate and be inserted into the tip. By penetrating the provided blade into the support layer, the blade and the support layer can be integrated to exhibit high support force. Furthermore, the amount of excavated earth and sand can be reduced as much as possible. Prior to carrying out the work of burying steel pipe piles, it is necessary to confirm the depth of the support layer by conducting a geological survey on the target ground. When excavating the ground (preceding excavation) prior to embedding the steel pipe piles, the operation of the excavator can be stopped in front of the support layer by controlling the excavation depth. To excavate the ground prior to burying the steel pipe pile, a spiral auger can be used. And when excavating the ground with a spiral auger, it is possible to excavate the ground by applying a thrust to the spiral auger and rotating it forward, and stirring the soil without excavating the ground by rotating it in the reverse direction, Alternatively, it is possible to pull out the spiral auger. When a steel pipe pile is buried in a site excavated as described above, earth and sand are excavated in advance on the ground reaching the support layer. Therefore, easy embedding can be realized by rotating the steel pipe pile. . Further, when the tip portion of the steel pipe pile reaches the support layer, by giving further rotation to the steel pipe pile, it is possible to penetrate the support layer by the blade provided at the tip, and the blades cut into the support layer. Thus, a high supporting force can be exhibited. The preferred embodiment of the method for burying a steel pipe pile will be described below. The method of embedding a steel pipe pile according to the present invention is such that a steel pipe pile provided with a spiral blade at its tip is directly buried by rotating the steel pipe pile, which is difficult to bury directly by rotating the steel pipe pile, or by rotating the steel pipe pile having a large adhesive force. It is a particularly advantageous method to apply to difficult clay ground. The blade provided at the tip of the steel pipe pile is formed in a spiral shape. When an axial thrust and rotation are applied, the blade penetrates and penetrates the ground with the rotation. However, when the target ground is gravel ground or clay ground, it is difficult or impossible to directly rotate and bury the steel pipe pile. By performing the method for embedding a steel pipe pile according to the present invention in such ground, a steel pipe pile capable of exhibiting a high supporting force can be smoothly embedded. That is, by excavating the position where the steel pipe pile is to be buried before the support layer in advance, even if the ground reaching the support layer is gravel ground or clay ground, It is possible to rotate the steel pipe pile to penetrate smoothly. When the tip of the steel pipe pile reaches the support layer, the rotation of the steel pipe pile is further continued, so that the blades provided at the tip can penetrate the ground of the support layer. At this time, since the support layer has not been excavated in advance, the blades can dig into the strong and fresh ground to exhibit a high support force. In the method for burying steel pipe piles according to the present invention, it is preferable to conduct a geological survey of a target site in advance to obtain a geological column showing the soil quality and N value in the depth direction. By obtaining this geological column diagram, it is possible to recognize the depth of the support layer, and when excavating the position where the steel pipe pile should be buried in advance, it is possible to reliably excavate the ground up to the front of the support layer It becomes. In particular, in the method for embedding a steel pipe pile according to the present invention, the support layer is not excavated prior to embedding the steel pipe pile, and when the blade of the steel pipe pile is cut into the support layer, the strong support layer is used. It is configured so that it can exhibit a high supporting force. For this reason, the steel pipe pile to be buried is not integrated with the loose ground, but is integrated with the ground constituting the strong support layer. Therefore, it is possible to exhibit a sufficient supporting force by the steel pipe pile without injecting the cement milk into the ground of the support layer excavated in advance. A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a method of burying a steel pipe pile according to the first embodiment. FIG. 2 is a diagram illustrating a method of burying a steel pipe pile according to a second embodiment. FIG. 3 is a view for explaining a configuration of a tip portion of a steel pipe pile which is advantageous for use in the embedding method of the second embodiment. First, a method of embedding a steel pipe pile according to a first embodiment will be described with reference to FIG. As shown in FIG. 1A, a spiral auger 1 composed of an auger 1a and a spiral rod 1b is installed at a position where a steel pipe pile is to be buried in a target site, and the ground auger 2 is formed by the spiral auger 1.
The excavation hole 4 is formed by excavating immediately before the support layer 3. The spiral auger 1 has a function of excavating the ground 2 and has a spiral rod 1b provided with a spiral cutting blade 1c, and the soil of the ground 2 has a cobblestone layer including cobblestone or a highly viscous clay. Even if it is a layer, it is constituted so that it can excavate smoothly. Further, the spiral auger 1 may be configured by attaching a drill bit 1d to the tip of the spiral rod 1b, or may be configured simply by the spiral rod 1b alone. In this manner, the ground 2 can be excavated by the spiral auger 1 regardless of whether or not the excavation bit 1d is attached to the tip. The spiral rod 1b does not need to form the spiral cutting blade 1c over its entire length, but may be formed by forming the spiral cutting blade 1c at a predetermined length at the tip. When the spiral rod 1b is rotated forward, the cutting blade 1c excavates the ground 2 with this rotation, and the excavated earth and sand is conveyed to the ground surface by the cutting blade 1c. For this reason, a part of the excavated earth and sand may be discharged from the end of the excavation hole 4 so as to rise to the ground surface. However, when the length of the cutting edge 1c is short, the function of discharging the excavated earth and sand is small. Therefore, the amount of waste soil can be reduced, which is advantageous. The spiral auger 1 is mounted on a not-shown excavator, and the excavator controls the excavation depth by a control device. Therefore, the value of the excavation depth of the ground 2 by the spiral auger 1 is measured as the excavation work progresses. By stopping the rotation of the spiral auger 1 when the excavation depth of the ground 2 by the spiral auger 1 becomes shortly before reaching the support layer 3 in the geological column diagram obtained by the previously conducted geological survey. It is possible to stop excavation work. When the excavation hole 4 reaching just before the support layer 3 is excavated in the ground 2 by the spiral auger 1, the auger 1a
The spiral rod 1b is rotated in the reverse direction, and the spiral rod 1b is pulled out of the ground 2 while maintaining the reverse rotation. By rotating the spiral rod 1b in the reverse direction, the cutting blade 1c exerts an upward excavation function. As a result, the earth and sand inside the excavation hole 4 is stirred, but is not discharged to the ground surface. Then, when the spiral auger 1 is pulled out from the excavation hole 4, as shown in FIG. By pulling out the spiral auger 1 from the excavation hole 4 while rotating the spiral rod 1b in the reverse direction, the amount of earth and sand discharged from the excavation hole 4 is minimized, and the amount of waste soil is reduced as much as possible. It is possible to do. The steel pipe pile 5 is inserted into the excavation hole 4 formed as described above while rotating from above. After the tip of the steel pipe pile 5 inserted into the excavation hole 4 reaches the support layer 3, by further continuing rotation, the blade 6 provided at the tip of the steel pipe pile 5 bites into the support layer 3 and proceeds. Thereby, the tip portion of the steel pipe pile 5 is firmly integrated with the support layer 3. By embedding the steel pipe pile 5 through each of the above steps, it is possible to penetrate the steel pipe pile 5 into the support layer 3 and exhibit a high supporting force. In particular, when the steel pipe pile 5 is buried, since the ground 2 is excavated in advance, even if the soil of the ground 2 is a gravel layer made of cobblestone or gravel or a highly viscous clay layer, the steel pipe pile 5 is smoothly rotated. It is possible to penetrate. Next, a method of burying a steel pipe pile according to a second embodiment will be described with reference to FIGS. In the drawings, the same portions and portions having the same functions as in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the embedding method of this embodiment, as shown in FIG. 3, a steel pipe pile 11 having two spiral blades 12 and 13 provided at a tip portion of a main body 11a is used, and the tip blade 12 is supported by a support layer. 3, and the blades 13 are embedded in the cement milk part 4a, so that a high supporting force can be realized. The blade 12 and the blade provided at the tip of the steel pipe pile 11
13 may be formed continuously with each other, or may be formed while maintaining an appropriate interval. In this embodiment, the blade
The blade 12 and the blade 13 are formed so as to keep an appropriate distance from each other. The procedure for embedding the steel pipe pile 11 will be described. As shown in FIG. 2 (a), at the position where the steel pipe pile 11 is to be buried, the spiral auger 1 excavates the ground 2 immediately before the support layer 3 to form an excavation hole 4. After the formation of the excavation hole 4, the spiral auger 1 is rotated in the reverse direction, and the excavated earth and sand is pulled out while stirring. At this time, cement milk is poured into a predetermined length portion (a length portion where the blades 13 of the steel pipe pile 11 can penetrate sufficiently) from the bottom of the excavation hole 4 (a portion near the surface of the support layer 3), Thereby, as shown in FIG. 2B, a cement milk part 4a and a soil part 4b are formed inside the excavation hole 4. After forming the cement milk part 4a in the drilling hole 4 and extracting the spiral auger 1 from the drilling hole 4,
As shown in FIG. 2C, the steel pipe pile 11 is penetrated while rotating. Since the earth and sand inside the excavation hole 4 is sufficiently loose, it is possible to smoothly penetrate the steel pipe pile 11 by rotating it. As the steel pipe pile 11 penetrates into the excavation hole 4, the blades 12 and 13 enter the cement milk part 4a and penetrate into the mixture of cement milk and earth and sand. Then, the blade 12 on the tip side abuts on the support layer 3, and as the steel pipe pile 11 rotates further, the blade 12 bites into the support layer 3, and
13 is embedded in the mixture in the cement milk part 4a. After the blades 12 bite into the support layer 3, the steel pipe piles
When the rotation of 11 is substantially one rotation, the entire blade 12 is
, It is possible to exhibit a high supporting force. At the same time, the blades 13 enter the mixture of the cement milk and the earth and sand constituting the cement milk portion 4a in the excavation hole 4 to realize the strong integration of the two. As described above, in the present embodiment, the support force of the blade 12 provided at the tip of the steel pipe pile 11 by the penetration into the support layer 3 and the support of the excavation hole 4 by the blade 13 by integration into the cement milk portion 4a. It is possible to expect the power, and it is possible to exhibit a higher supporting force by adding the supporting force of both. As described above in detail, in the method for burying steel pipe piles according to the present invention, the ground where steel pipe piles are to be buried is excavated in advance to the ground in front of the support layer. Since the steel pipe pile was rotated into the hole and penetrated and the blade at the tip was cut into the support layer, the ground of the support layer was not loosened,
A high support force can be exhibited by the strong support layer. By excavating the ground in advance with a spiral auger, the steel pipe pile can be smoothly rotated and penetrated regardless of the soil properties of the ground. The excavated soil can be buried without discharging, and waste soil can be reduced as much as possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining a method of embedding a steel pipe pile according to a first embodiment. FIG. 2 is a diagram illustrating a method of burying a steel pipe pile according to a second embodiment. FIG. 3 is a diagram illustrating a configuration of a tip portion of a steel pipe pile that is advantageous for use in the embedding method of the second embodiment. [Description of Signs] 1 Spiral auger 1a Auger 1b Spiral rod 1c Cutting edge 1d Drilling bit 2 Ground 3 Support layer 4 Drilled hole 5,11 Steel pipe pile 6,12,13 Blade

Claims (1)

Claims 1. A method for burying a steel pipe pile having a spiral blade at a tip thereof, wherein the steel pipe pile is excavated before a support layer at a position where the steel pipe pile is to be buried. Thereafter, the steel pipe pile is rotated and buried up to the excavation site, and then a spiral blade provided at the tip is penetrated into the support layer.