JP2005200962A - Method for controlling refusal of pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling the refusal of a pile capable of deciding the refusal by determining the bearing capacity of the pile based on a measured value without requiring the pile-driving construction of a test pile. <P>SOLUTION: A steel pipe pile 1 is penetrated up to a refusal predetermined place, and soil and sand at the front end section of the steel pipe pile is removed. A penetration tester 5 is inserted into the steel pipe pile 1, and the N value of the ground at the front end section of the steel pipe pile is measured and a sample is gathered. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stop management method for pile driving a tubular pile having an opening at the tip of a steel pipe pile or the like.

  In pile driving construction such as steel pipe piles, the stopping management is important for obtaining an appropriate support force. Patent Document 1 describes the pile penetration amount per one hit at the time of stopping the test pile and the penetration resistance at that time. And the relationship between the pile penetration per hit and the penetration resistance at that time after a predetermined time from this point in time, and the relationship between the penetration resistance at that time, and the increase in bearing capacity due to ground recovery is determined by measurement. In addition, a method of placing a foundation steel pipe pile that estimates whether or not the target pile support force has been reached from the amount of pile penetration per hit when piled with a steel pipe pile is disclosed.

  However, in the method disclosed in Patent Document 1, the actual support capacity of the pile is estimated based on the soil investigation data by the test pile, and the support capacity of the pile is the support ground at the pile driving position. Since this is not based on the actual measurement value, there is a problem that variations and errors occur in the actual supporting force of the pile, and an appropriate supporting force cannot be obtained. Moreover, in addition to the actual pile driving, it is necessary to pile the test piles, and there is a problem that extra costs and time are required. Further, since a drop hammer device or the like for measuring the pile penetration amount per hit is required, it is difficult to construct in a narrow area, and there is also a problem that noise and vibration are generated at the time of hitting.

In addition, as described in Non-Patent Document 1, as a method for managing the stopping of steel pipe piles, a method is also known in which the rotational driving current of a steel pipe pile is read with an ammeter and the bearing capacity of the pile is estimated from this current value. However, even in this method, since the bearing capacity of the pile is not based on the actual measurement value, variations and errors occur in the actual bearing capacity of the pile.
JP-A-6-346443 Nobuyuki Narita, “Steel Pipe Pile (Design and Construction)” revised edition, Steel Pipe Pile Association, September 30, 1998, p. 440

  The problem to be solved by the present invention is to provide a pile stop management method that does not require pile driving construction of test piles and can determine the stop determination by grasping the supporting force of the piles based on the actually measured values. It is in.

  The present invention relates to a pile management method for pile construction of a tubular pile having an opening at the tip, and after the pile has been penetrated to the planned stop position, the soil at the tip of the pile is removed and the pile is placed in the pile. The penetration tester is inserted to measure the N value of the ground at the tip of the pile.

  In addition, at the time of measuring the N value, it is possible to sample the ground at the tip of the pile.

  According to the pile stop management method of the present invention, since the N value measurement of the ground at the planned stop position of the pile is actually performed, the support force of the pile at the expected stop position is accurately grasped based on the actually measured N value. be able to.

  In addition, by collecting the ground sample during N value measurement, it is possible to more accurately grasp the supporting force of the pile, and it is possible to grasp in detail the properties such as the stratum at the stopping position.

  In addition, since the properties of the ground at the planned stop position are investigated using holes made by tubular piles that have been struck, surveys can be carried out even in narrow areas, and there is no need for separate borehole surveys. You can complete the survey. In addition, since there is no need for testing piles or equipment for preliminary surveys, the cost required for the survey can be reduced.

  Hereinafter, embodiments of the present invention will be described by way of examples in which the present invention is applied to the management of steel pipe piles.

  Drawing 1 is an explanatory view showing the procedure of pile driving construction of a steel pipe pile. In the pile driving construction of a steel pipe pile, first, the steel pipe pile 1 is lifted and set at a predetermined pile driving position as shown in FIG. Next, as shown in FIG.1 (b), the rotational drive device 2 gives the steel pipe pile 1 a rotational force and a propulsive force, and rotates it in the ground. When the pile driving depth of the steel pipe pile 1 is deep, a plurality of steel pipe piles 1 are added and piled as shown in FIG. And as shown in FIG.1 (d), the steel pipe pile 1 is rotationally penetrated to the predetermined depth (scheduled stop position).

  In the steel pipe pile stop management method of the present invention, after the steel pipe pile is rotated and penetrated to the planned stop position, the N value measurement and sampling of the ground at the planned stop position are performed using the steel pipe pile according to the procedure shown in FIG.

  First, as shown in FIG. 2A, the core tube 3 is inserted into the steel pipe pile 1 that has penetrated to the planned stop position, and the inside of the steel pipe pile 1 is lowered while the rod 4 is added. And the earth and sand which entered the front-end | tip part of the steel pipe pile 1 are removed while rotating or driving the core tube 3 with the rotational drive apparatus 2, and the opening part 1a of the front-end | tip of the steel pipe pile 1 is shown in FIG.2 (b). Open. Thereafter, the core tube 3 is pulled up and removed from the tip of the rod 4, and a penetration tester is attached instead. In this example, a standard penetration test sampler 5 defined in JIS A-1219 was attached as a penetration tester. Next, as shown in FIG. 2 (c), the standard penetration test sampler 5 is lowered to the tip end portion of the steel pipe pile 1, that is, the planned stop position of the steel pipe pile 1. Then, as shown in FIG. 2 (d), a knocking head 6 and a guide rod 7 are attached to the base end of the rod 4, and a monken 8 is mounted on the guide rod 7 so as to be movable up and down, and the monken 8 and the winch 9 are attached to the pulley. 10 is connected by a wire 11.

  When the above preparation is completed, the N value of the ground at the tip portion (scheduled position) of the steel pipe pile 1 is measured by the standard penetration test method specified in JISA-1219, and then the standard penetration test sampler 5 is attached. A ground sample collected and measured for N value is collected. Then, based on the measured N value, the support force of the steel pipe pile at the planned stop position is calculated, and whether or not the support position is appropriate is determined to determine whether the stop position is appropriate. If the bearing capacity is insufficient, measures such as driving the steel pipe pile deeper are taken, and the above-mentioned standard penetration test is performed again at the new stop position to determine whether the stop position is appropriate.

  As described above, in the present invention, the N value is measured at the planned stop position of the steel pipe pile, and the stop management of the steel pipe pile is performed based on the actually measured value. Therefore, the supporting force of the steel pipe pile can be directly grasped, and the supporting force can always be an appropriate value. In addition to measuring the N value, sampling is also performed. By analyzing the sample, it is possible to grasp the supporting force of the steel pipe pile more accurately, and it is also possible to grasp the stratum at the stopping position. .

  The present invention is not limited to the management of steel pipe piles, and can be applied to the management of any piles having an opening at the tip, such as a cylindrical concrete pile.

It is explanatory drawing which shows the procedure of the pile driving construction of a steel pipe pile. It is explanatory drawing which shows the procedure of the stop management method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel pipe pile 1a Opening part of steel pipe pile tip 2 Rotation drive device 3 Core tube 4 Rod 5 Standard penetration test sampler (penetration tester)
6 knocking head 7 guide rod 8 monken 9 winch 10 pulley 11 wire

Claims (2)

  This is a pile stop management method for pile pile construction with an opening at the tip, and after the pile has been penetrated to the expected stop position, the soil at the tip of the pile is removed, and a penetration tester is installed in the pile. A pile stop management method comprising inserting and measuring the N value of the ground at the tip of the pile.   The pile stop management method according to claim 1, wherein sampling of the ground at the tip of the pile is performed at the time of measuring the N value.

Images