JP3078122B2 - Horizontal loading tester for ground survey - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be obtained by penetrating a ground with a boring machine, inserting a rod-shaped main body into the hole, applying a predetermined pressure horizontally to the side wall of the hole, and performing a penetration test or the like. The present invention relates to a horizontal loading tester for investigating the strength and deformation characteristics of the ground in addition to the characteristics.

[0002]

2. Description of the Related Art Conventionally, various methods have been employed to predict liquefaction or the like mainly by investigating properties such as the strength of sandy ground and ground having high N value. Among them, there is a method in which the ground is sampled and measured by a specimen test. However, in this method, there is a problem that a characteristic difference from the actual ground to be measured is unavoidable and the characteristic at the original position cannot be grasped. Therefore, a horizontal radial pressure is applied to the hole wall by pressing the rubber tube inside the borehole,
A horizontal load tester that measures the pressure and the displacement of the hole wall at that time has come to be used.

[0003]

However, in the above-mentioned horizontal load tester, as a method of applying pressure to the hole wall, a method of inflating the bomb tube with compressed air or the like, or directly pressing the hole wall with a hydraulic jack or the like is used. Although it is known, the volume change of the pressure fluid was calculated on the ground to obtain the displacement of the hole wall. In such a calculation method, various correction values and the like must be taken into consideration, which is troublesome. Further, the pressurizing means using a hydraulic jack has a problem that the apparatus itself is large and the structure is complicated, the pressurizing speed is low, and the vibration state such as an earthquake cannot be reproduced. As a means for pressurizing the hole wall, there is no device using a shape memory alloy.

[0004] The present invention has been made in view of the above problems, and has as its object to provide a horizontal load testing machine having a simple structure using a shape memory alloy.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the present invention and to achieve the above-mentioned object, the gist of the present invention is to insert a hole into a boring hole formed in the ground and to apply horizontal pressing means to the hole wall through a loading plate. To the ground by measuring the amount of displacement of the hole wall.
In the horizontal loading tester for knowing the liquefaction characteristics or dynamic characteristics of the above, the horizontal pressing means is attached to the end of the telescopic rod
Repeatedly deformed with the provided soil / water pressure gauge and loading plate
Shape memory alloy pressurized body and heat it to deform
An electric heating means, and electrically connected to the heating means,
Power supply and control circuit provided in
The horizontal loading test is performed by pressing the fixing plate against the hole wall.
A porous wall fixing device for position fixing the machine consists in further provided a displacement meter for measuring the displacement of the pore walls.

[0006]

According to the horizontal loading tester of the present invention, the loading plate which directly presses the hole wall is compressed and expanded by deformation of the shape memory alloy. In order to deform this shape memory alloy, the coil wound around the shape memory alloy is energized from a power supply and heated, and this heat turns the arc-shaped shape memory alloy into a straight line. The loading plate is moved to the hole wall side to press the hole wall. Further, if the control circuit sets a cycle for energizing the coil and performs the pressurizing action by the horizontal pressurizing means, the liquefaction characteristic of the ground or the ground is changed to a state similar to the vibration at the time of an earthquake or the like.
The dynamic characteristics of can be known.

[0007]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a front view of a horizontal load testing machine according to the present invention, and FIG. In the drawing, reference numeral 1 denotes a horizontal loading tester, 2
Is a load plate, 3 is a soil / water pressure gauge, 4 is a pressure body made of a shape memory alloy, 5 is a coil, 6 is a lead wire, 7 is a power supply, 8 is a control circuit, 9 is a telescopic rod, 10 is a displacement gauge, 11 Denotes hole wall fixing devices.

As shown in FIG. 1, a horizontal loading tester 1 according to the present invention has a hole
And a horizontal pressure means 13 and a displacement meter 10.

The hole wall fixing device 11 is provided with an extendable rod 11b and a fixing plate 11a provided at the tip thereof, which are equally arranged at three places in the circumferential direction.

The horizontal pressing means 13 will be described with reference to FIG.
A support member 9a extending horizontally from the above, a telescopic rod 9 fitted to and retractable from the support member 9, an earth / water pressure gauge 3 and a loading plate 2 provided at the end of the telescopic rod 9, An arc-shaped shape memory alloy pressurizing member 4 fixed to the telescopic rod 9 and the support member 9a, and a lead wire 6 wound around the shape memory alloy pressurizing member 4 from the end thereof. It comprises a power supply 7 and heating means for the coil 5 electrically connected to the control circuit 8 via the power supply 7.

The displacement meter 10 is provided on the rod body 12 slightly above the horizontal pressurizing means 13. When the measuring rod 10a is brought into contact with the packing plate 2 described above,
The displacement of the hole wall is measured. This displacement data is sent to a measuring instrument on the ground and measured.

In order to investigate the characteristics of the ground 14 using the horizontal load tester 1 of the present invention thus formed,
First, a hole is formed in the ground 14 using a boring machine. Then, the horizontal load tester 1 is inserted into the hole from the ground. Next, the hole wall fixing device 11 is operated to press the fixing plate 11a uniformly in three directions against the hole wall, thereby fixing the position of the horizontal loading tester 1. This insertion amount is measured separately electrically.

Next, water is statically injected into the pores to fill the pores.
Then, the control circuit 8 and the power supply 7 energize the coil 5 of the pressurizing means 13. Then, the coil 5 generates heat, and the heat deforms the pressurizing member 4 made of a shape memory alloy, as shown in FIG.

Thus, the pressure body 4 made of the shape memory alloy is formed.
At first, the arc shape is quickly extended in a straight line and becomes longer, and the earth / water pressure gauge 3 and the loading plate 2 are radially pressed in the horizontal direction by using the support member 9a as a reaction force. By forcibly deforming the hole wall quickly in this way,
The water pressure gauge 3 can measure the water pressure. When the heating of the coil 5 is completed, the shape memory alloy pressurized body 4 is cooled by surrounding water and returns to an arc shape again.

At the same time as the hole wall is forcibly displaced by the horizontal pressing means 13, the measuring rod 10 of the displacement meter 10 is
By extending a, the displacement of the hole wall is measured. Fig. 3 (a),
The earth pressure and water pressure of the ground 14 as shown in (b) are obtained, and the strength and liquefaction characteristics of the ground 14 are estimated from these.

Further, the control circuit 8 operates as shown in FIG.
By setting the energization cycle to the coil 5 as shown in FIG.
It is also possible to grasp the dynamic characteristics of the ground 14 by repeatedly deforming it into an arc shape and a straight line in a cycle to rapidly expand and contract, and repeatedly apply vibration to the ground 14 as in an earthquake. Further, although the coil 5 is used as the heating means, the shape memory alloy may be directly heated and deformed by energizing the shape memory alloy.

[0017]

As described above, the horizontal loading tester of the present invention is inserted into a boring hole drilled in the ground and horizontally pressed against the hole wall via the loading plate by horizontal pressing means. Liquefaction characteristics of the ground or dynamic
In a horizontal load tester for knowing the characteristics, the horizontal pressure means is provided with an earth / water pressure gauge provided at an end of a telescopic rod and
Loading plate and pressurized body made of shape memory alloy that is repeatedly deformed
And an electric heating means for heating and deforming the heating,
Power and control circuits, which are electrically connected to
And a fixing plate is formed so as to be able to expand and contract horizontally in the horizontal direction.
To secure the horizontal load tester in position
A constant unit, since further comprising providing a displacement meter for measuring the displacement of the hole wall, the entire apparatus becomes made simple in comparison with the pressure means pressurize the conventional hydraulic jack, such as, pressurization rate The water pressure can be easily measured, and the ground survey can be easily performed at the original position. In addition, since the pressurized body made of a shape memory alloy is used, it is possible to apply vibration such as at the time of an earthquake to the hole wall, and it is possible to grasp the liquefaction characteristics of the ground and the dynamic characteristics of the ground .

[Brief description of the drawings]

FIG. 1 is a front view of a horizontal load testing machine according to the present invention.

FIG. 2 is also a part before operation (a) and during pressurization (b)
FIG.

FIG. 3 is a table of measured earth pressure and water pressure (a) and (b);
It is a table | surface (c) which shows a mode that it is forcibly deformed periodically.

[Explanation of symbols]

1 horizontal loading tester, 2 loading plate, 3 soil / water pressure gauge, 4
Shape memory alloy pressurized body, 5 coils, 6 lead wires,
7 power supply, 8 control circuit, 9 telescopic rod, 10 displacement meter, 11 hole wall fixing device, 13 horizontal pressing means.

Claims (1)

(57) [Claims] 1. A liquefaction characteristic of a ground or a ground hole which is inserted into a boring hole formed in the ground and is horizontally pressed by a horizontal pressing means via a loading plate to measure a displacement amount of the hole wall.
In a horizontal loading tester for knowing dynamic characteristics, the horizontal pressing means may be provided on a soil provided at an end of a telescopic rod.
Water pressure gauge, loading plate, and shape memory alloy that is repeatedly deformed
Pressurizing body and electric heating means for heating and deforming the pressing body
And a power source electrically connected to the heating means and provided on the ground
And telescopically formed horizontally and the control circuit, position the horizontal loading test machine by pressing a fixing plate to the hole wall
Hole wall fixing device and, further by providing a displacement meter for measuring the displacement of the bore wall, comprising as said ground survey horizontal loading test machine for location fixed.