JP3684097B2 - In-pipe soil measurement method during construction of open-end steel pipe piles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring the height of soil that enters a pipe when a steel pipe pile with a lower end released is penetrated into the ground.
[0002]
[Prior art]
The indentation support force of steel pipe piles used as foundation piles for buildings and civil engineering structures is the sum of peripheral surface friction force and tip resistance force. Among these, in the case of an open-ended steel pipe pile whose tip is released in the calculation of the tip resistance force, it is possible to evaluate the tip resistance force due to the earth and sand that has entered the pipe at the time of intrusion construction by driving or press fitting blocking the tip portion of the steel pipe pile. However, it is known that when the diameter of the steel pipe pile is increased, this clogging action tends to penetrate the soil in the pipe from the tip and tends to make it difficult to obtain the clogging action. Hereinafter, it is necessary to know the blockage rate).
Since this blockage is closely related to the height of the soil in the pipe, the blockage rate can be estimated by measuring the height of the soil in the pipe (the distance from the steel pipe pile tip to the surface of the soil that has entered the pipe).
[0003]
And this obstruction | occlusion rate becomes a parameter | index which evaluates the tip resistance force of a steel pipe pile. In other words, as the steel pipe pile with the lower end released penetrates into the ground, the soil penetrates into the pipe and the height of the soil in the pipe increases, but at a certain height, the frictional force between the inner peripheral wall of the steel pipe pile and the soil Thus, the effect of closing the tip can be expected, so that the tip resistance force of the closed cross-sectional area can be evaluated in the bearing capacity calculation. For example, if there is no pipe soil at all, the tip resistance can be evaluated only for the plate thickness area of the steel pipe pile, but if there is sufficient pipe soil height, the steel pipe pile tip will be closed due to the frictional resistance of the pipe inner peripheral surface. The entire area of the tip can be evaluated as the tip resistance.
[0004]
The measurement of the soil height in the pipe is an important parameter in the construction of the steel pipe pile in addition to the intrusion construction of the steel pipe pile by driving or press fitting.
[0005]
The rotary press-in method allows the steel pipe pile with blades on the outer side of the lower end to be penetrated by noise-free and vibration-free and press-fitted easily. Can demonstrate. In addition, this construction method has the characteristics that can evaluate the bearing capacity from the measurement data during construction such as torque at the time of rotary press-fitting, pressure input, etc., so highly reliable construction management while checking the bearing capacity for each steel pipe pile Can do. In this bearing capacity evaluation, if the height of the pipe soil during construction of steel pipe piles can be measured continuously, the bearing capacity is calculated in real time in combination with this data and construction management data such as torque and pressure input. It becomes possible.
[0006]
Conventionally, the pipe soil measurement method used in the steel pipe pile striking method and press-fitting method is as shown in FIG. 8, in which a measuring rope 12 with a weight 11 is suspended from the top of the steel pipe pile 1 into the pipe. There was a simple method for measuring the distance L1 between the surface 2a of the pipe soil 2 and the top of the steel pipe pile 1 and subtracting it from the total length L of the steel pipe pile 1 to obtain the pipe soil height h.
[0007]
[Problems to be solved by the invention]
However, the above-mentioned conventional method needs to interrupt the construction of the steel pipe pile at the time of measurement, and it is dangerous because it is a work at a high place when the top of the steel pipe pile is higher than the ground. This was done after the completion of the placement and press-fitting. For this reason, there was a problem that continuous data of the pipe soil during construction could not be obtained.
The object of the present invention is to solve this problem, and to make it possible to measure the height of the soil in the pipe continuously and in real time during the penetration of the steel pipe pile.
[0008]
[Means for solving the problems]
In the present invention, in order to achieve the above object, the following configuration is adopted.
The invention according to claim 1 is the method of measuring the height of the pipe soil 2 of the open-ended steel pipe pile 1 with the open end provided with a lightwave distance meter 4 attached to a detachable clamp 3 in the steel pipe pile 1, It is the pipe soil measurement method at the time of construction of the open end steel pipe pile characterized by measuring the height h of the soil which invades in the pipe when penetrating the pile 1 into the ground without contact.
[0009]
In the invention according to claim 2, the set position of the light wave distance meter 4 attached to the detachable clamp 3 in claim 1 is set so that the light wave beam 5 does not interfere with the pipe inner wall of the steel pipe pile 1 and the clamp set error and beam characteristics. This is a method for measuring the soil height in the pipe within the limit distance A related to.
[0010]
The invention of claim 3 is a rotary press-fit pile construction method in which an open-ended steel pipe pile 1 having blades 8 provided on the outer surface of the lower end portion of the steel pipe pile is rotationally press-fitted and embedded therein. An optical distance meter 4 attached to the pipe is installed, and the pipe inner height measurement data is wirelessly transmitted to the ground receiver 10 from a transmitter 9 provided at the top of the steel pipe pile, and the pipe 1 is inserted into the pipe when penetrating into the ground. It is the soil measurement method in the pipe | tube at the time of construction of the open end steel pipe pile characterized by measuring the height h of the soil which penetrate | invades into a non-contact.
[0011]
[Action]
In the pipe soil height measuring method of the present invention, when the steel pipe pile 1 penetrates into the ground, the light wave distance meter 4 is fixedly attached to the clamp 3 provided detachably above the open end steel pipe pile 1. The distance L2 to the surface 2a of the pipe soil is continuously measured in a non-contact manner by the light wave beam 5 oscillated from the light wave distance meter 4. Various types of laser rangefinders can be used as the lightwave rangefinder 4 to be used, but it is desirable to use a semiconductor laser rangefinder that can use a compact oscillator for setting in a narrow space in the steel pipe pile.
[0012]
This light wave distance meter 4 is set on the pipe inner wall of the steel pipe pile 1 by the clamp 3, but normally, several steel pipe piles are extended by welding and joining several pieces of about 10-20m in length into the ground. Therefore, the clamp 3 needs to be detachable so that the set can be easily changed when the steel pipe pile 1 is joined.
[0013]
The clamp 3 uses a mechanism that presses and holds the inner wall of the pipe of the steel pipe pile 1, and is preferably one that can be detached from the ground by remote operation.
[0014]
If the optical distance meter 4 set in the steel pipe pile 1 is too far from the pipe soil surface 2a, the influence of the pipe wall becomes a problem in a narrow steel pipe. One of the reasons is a problem of tilt accuracy when the lightwave distance meter 4 is set by the clamp 3. That is, when the light wave distance meter 4 is inclined and set in the steel pipe pile 1, if the distance from the pipe soil surface 2a is long, as shown in FIG. The light beam 5 deviates from the inner surface 2a of the pipe and hits the pipe wall to be refracted and reflected to cause a measurement error or make measurement impossible. In addition, when a semiconductor laser is used, the apparatus can be made compact. However, since the condensing degree of the laser beam 5 is low, the diffused light wave beam 5 interferes with the tube wall as shown in FIG. End up. Also in this case, the light wave beam 5 hitting the tube wall is refracted and reflected, which causes a measurement error or measurement failure.
[0015]
The invention of claim 2 solves this problem, and the light wave rangefinder 4 is set within a limit distance A related to the clamp set error and the beam characteristics so that the light beam 5 does not interfere with the tube wall. It is a thing. Here, the limit distance A is a distance that is obtained by adding the light beam radius (r1) to the deviation (r2) of the optical axis of the light beam 5 due to the clamp set tilt error, which is the same as the radius (r) of the steel pipe pile 1. is there. That is, as shown in FIG. 3, when the tilt error when the optical distance meter 4 is clamped is set to (s degrees), A that satisfies A × (tans) + (r1) = r is set as the limit distance.
[0016]
The invention of claim 3 is a construction method in which the steel pipe pile 1 is rotationally press-fitted, and the height of the pipe soil 2 is measured in a non-contact manner with the optical distance meter 4. When the rotary press-fitting method is used as the penetration construction means for the steel pipe pile 1, the steel pipe pile 1 rotates at the time of measurement, so that the signal transmission of the lightwave distance meter 4 cannot be performed by wire. For this reason, the data of the pipe soil height measured by the light wave distance meter 4 is wirelessly transmitted from the transmitter 9 provided on the top of the steel pipe pile 1 to the receiver on the ground and measured.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of the present invention. The steel pipe pile 1 to which the present invention is applied is an open-ended steel pipe pile mainly having a large diameter of 500 mm or more and a free end, and penetration into the ground is performed by a hammering hammering method, a press-fitting method, or a rotary press-fitting method. by.
[0018]
When the open-end steel pipe pile penetrates into the ground, the soil penetrates into the penetration from the pile tip, and when the height of the pipe soil 2 increases, the pile tip is blocked. The present invention provides a method for continuously measuring the height of the pipe soil 2 in the steel pipe pile 1 in a non-contact manner with the light wave distance meter 4. The measuring means is that a light wave distance meter 4 attached to a detachable clamp 3 is set at a predetermined position in the steel pipe pile 1 and a light beam 5 is oscillated toward the tip of the steel pipe pile, and the surface 2a of the pipe soil 2 is The reflected light wave beam 5 is captured and signal-processed by the measuring device 4a to measure the distance L2, and subjected to arithmetic processing to know the pipe soil height h.
[0019]
The light wave distance meter 4 is mounted on the clamp 3 and set at a predetermined position of the steel pipe pile 1 using a semiconductor laser beam distance meter so that a small oscillator can be used.
[0020]
As shown in FIG. 4, the clamp 3 to which the optical distance meter 4 is attached presses and holds the inner wall of the steel pipe pile so as to be detachable by the telescopic cylinder 3a. The telescopic cylinder 3a is pneumatic, hydraulic, electric or manually operated. Can be used.
[0021]
Also, the clamp 3 shown in FIG. 5 is detachably set by remote control from the ground without using a drive source, and the left and right clamp shoes 3b for pressing the inner wall of the steel pipe pile are pin-coupled 3d to one end of the arm 3c. Furthermore, these arms are pin-coupled 3e at the center of the steel pipe pile, and a spring 3f is arranged in the extending direction of the arm 3c, and a detachable loop 6 is attached to the pin-connecting portion 3e of the arm 3c. A positioning rope 7 is attached to each clamp shoe 3b. Both the detachable rope 6 and the positioning rope 7 are arranged so as to reach the ground via the steel pipe pile top, and the detachable set of the clamp 3 can be freely set on the ground.
[0022]
When the clamp is moved, when the clamp is moved, the arm 3c is rotated by the weights of the clamp shoe 3b and the arm 3c by using the weights of the clamp shoe 3b and the arm 3c as shown in FIG. The clamp shoe 3b is pulled toward the steel pipe pile center side and detached from the pipe wall. Next, after the clamp 3 is moved to a predetermined position by the positioning rope 7 with the detachable rope 6 pulled, when the detachable rope 6 is loosened, as shown in FIG. It moves in the direction and presses the tube wall to be clamped. In order to increase the pressing force, the weight 3g may be suspended from the pin connection portion 3e of the arm 3c as shown in the figure to increase its own weight. The clamp 3 may use a known means other than the above example.
[0023]
As described above, when the light wave distance meter 4 (and the clamp 3) is set within the limit distance A within a certain range from the surface 2a of the pipe soil, stable measurement can be obtained without being affected by the inner wall of the pipe. Since the inclination s at the time of setting can be tolerated to some extent, the setting operation becomes easy. For example, if a semiconductor laser having a diffusion characteristic of the light wave beam 5 of 10 m and 4 cm is used and a tilt error s at the time of setting is allowed at a steel pipe pile of 1,000 mm and an inner diameter of 5 degrees, the limit distance A at which the light beam 5 does not touch the tube wall Is about 6 m, so set the light wave rangefinder 4 at a distance less than this from the pipe soil surface 2a.
When the tilt error during setting is allowed twice under the same conditions, the limit distance A is about 13 m.
[0024]
If the light wave distance meter 4 (clamp 3) is set too close to the surface of the pipe soil, the light wave distance meter 4 (clamp 3) will move to the surface of the pipe soil due to the intrusion of the steel pipe pile. Since it comes in contact with 2a, it is necessary to change the set frequently, which is not preferable. In practice, the limit distance A is preferably in the range of about 3 to 10 times the diameter of the steel pipe pile 1.
[0025]
【Example】
FIG. 7 is a diagram showing an embodiment of a method for measuring the pipe soil 2 in the steel pipe pile 1 constructed by the rotary press-fitting method.
As shown in Figs. 7a and 7b, the rotary press-in pile is an optical distance meter 4 set in the steel pipe pile 1 so that an open-ended steel pipe pile with blades 8 provided on the outer surface of the lower end of the steel pipe pile is rotary-pressed and embedded. The signal cannot be transmitted to the ground measurement device by wire. For this reason, measurement data is transmitted wirelessly from the oscillator 9 provided on the top of the steel pipe pile to the receiver 10 on the ground.
[0026]
The clogging rate can be estimated from the relationship between the soil quality, pipe diameter, and other conditions verified in advance and the pipe soil height from the pipe soil height data during the intrusion work of the steel pipe pile obtained by the above means.
[0027]
Moreover, the state of the tip blockage can also be estimated in real time from the relationship between the change in the pipe soil height data obtained continuously and the change in the penetration amount of the steel pipe pile. That is, when the pipe soil height increases in the same way as the penetration of the steel pipe pile, it is estimated that the tip is released (blockage rate 0%), and the pipe pile is penetrating despite the penetration. When the soil height does not change and shows a constant value, it can be estimated that the tip is blocked (blocking rate is 100%). And the tip resistance force of a steel pipe pile can be evaluated by this obstruction | occlusion rate.
[0028]
【The invention's effect】
According to the present invention, since the height of the soil in the pipe at the time of the penetration construction of the open-ended steel pipe pile with the tip released can be continuously measured by the light wave distance meter set in the pipe, measurement without interruption of the pile penetration construction is possible. You can work safely. According to the second aspect of the present invention, since the light wave distance meter is set and measured within a certain range from the surface of the pipe soil, measurement can be performed stably without being affected by the pipe wall. The obtained data on the soil height in the pipe can be used to accurately estimate the closed state of the steel pipe pile tip, and this will be reflected in the evaluation of the tip bearing capacity of the steel pipe pile. In particular, when the present invention is applied to the rotary press-in pile method, the tip bearing capacity evaluation during the steel pipe pile penetration construction can be accurately obtained in real time, and the steel pipe pile bearing capacity can be greatly improved.
[Brief description of the drawings]
FIG. 1A is a side sectional view showing an embodiment of a method for measuring the soil height in a pipe according to the present invention.
FIG. 2A is a side explanatory view showing a state of tube wall interference of a light wave beam (set error effect), and FIG. 2B is a side view showing tube wall interference of a light wave beam (beam diffusion effect).
FIG. 3 is an explanatory diagram of a limit distance when a lightwave distance meter is set.
FIG. 4 is an explanatory diagram of a clamp setting example.
FIG. 5 is an explanatory diagram of another example of clamp setting (at the time of setting).
FIG. 6 is an explanatory diagram of another example of a clamp set (at the time of detachment).
FIGS. 7A and 7B are a side view of an embodiment in which the present invention is applied to a rotary pile method and a partially enlarged view of a steel pipe pile tip.
FIG. 8 is a diagram showing an example of conventional pipe soil height measurement.
[Explanation of symbols]
1 Steel pipe pile 2 Pipe soil
2a Soil surface 3 Clamp 4 Light wave rangefinder 5 Light wave beam

Claims (3)

In the method of measuring the height of the soil inside the open-ended steel pipe pile with the tip released, an optical distance meter attached to a detachable clamp is set in the steel pipe pile and enters the pipe when the steel pipe pile penetrates into the ground In-pipe soil measurement method during construction of open-ended steel pipe piles, characterized in that the height of soil to be measured is measured in a non-contact manner. 2. The open-ended steel pipe pile according to claim 1, wherein a set position of the optical distance meter is set within a limit distance related to a clamp set error and a beam characteristic so that the light wave beam does not interfere with a pipe inner wall of the steel pipe pile. Pipe soil measurement method during construction. In the rotary press-in pile method, in which an open-end steel pipe pile with blades provided on the outer surface of the lower end of the steel pipe pile is rotationally press-fitted and installed, a light wave distance meter attached to a detachable clamp is set in the steel pipe pile. The measurement data is wirelessly transmitted from a transmitter provided on the top to a receiver on the ground, and the height of the soil entering the pipe is measured in a non-contact manner when the steel pipe pile penetrates into the ground. The pipe soil measurement method at the time of construction of the open end steel pipe pile of Claim 1 or Claim 2.

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