JP2873221B2 - Loading test method and loading device for checking the bearing capacity of foundation pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loading test method for inspecting a bearing capacity of a foundation pile driven into the ground, and a loading device used for the loading test.

[0002]

2. Description of the Related Art A loading device for inspecting the bearing capacity of a foundation pile is:
For example, it is described in JP-A-57-100210. The apparatus described in this publication is shown in FIG. The device in this figure comprises a plurality of reaction piles 2 adjacent to and around a foundation pile 1.
Type. The reaction pile 2 is connected at its upper end with a girder 4 and the girder 4 is arranged above the foundation pile 1. The girder 4 and the foundation pile 1 are connected by a hydraulic jack 3 having a load cell (not shown).
The hydraulic jack 3 pushes and loads the foundation pile 1 and inspects the bearing capacity of the foundation pile 1.

[0003]

The conventional loading device shown in FIG. 1 drives a plurality of reaction force piles 2 adjacent to the foundation pile 1 and connects them with the girder 4, so that the cost of the loading test is extremely low. Get higher. It not only costs a considerable amount of time to drive a plurality of reaction piles 2, but also securely connects the girder 4 having an extremely tough structure, and further connects the hydraulic jack 3 and the like to the lower surface of the girder 4. This is because the supporting force is measured. Further, the loading device shown in FIG. 1 performs a loading test by driving the reaction force pile 2 specifically for inspection, so that the loading test takes a considerable amount of time, and there is a disadvantage that the supporting force cannot be easily and quickly inspected. .

Further, the loading device shown in FIG.
, A pull-out force acts on the reaction force pile 2. Therefore, when an extremely strong load is applied to the foundation pile 1, the reaction pile 2 may move upward. When the reaction force pile 2 moves, the support force of the foundation pile 1 cannot be accurately tested. This adverse effect can be prevented by mounting a large number of division cylinders on the spar 4 as shown in FIG. However, in this loading test method, in addition to driving the reaction pile 2, a large number of partial cylinders are placed on the girder 4, so that the cost and time are further increased, and the bearing capacity of the foundation pile 1 is inspected efficiently at low cost. There are drawbacks that can not be done.

[0005] The present invention has been developed for the purpose of solving such a drawback. An important object of the present invention is to provide a loading test method and a loading device that can easily and easily inspect the supporting force of a foundation pile efficiently at low cost.

[0006]

In order to simplify the loading test of the foundation pile 1, the inventor of the present invention has made it possible to directly load the separation cylinder 5 onto the foundation pile 1.
Was developed. This method does not require the use of the reaction pile 2. This is because the dividing cylinder 5 directly applies a load to the foundation pile 1. For this reason, this loading test method has the feature that the bearing capacity of the foundation pile 1 can be reliably and extremely accurately tested in a very short time. However, since this loading test method uses a split cylinder to apply a load to the foundation pile, it is necessary to prepare a large number of split cylinders having different weights. This is because the load for testing the bearing capacity differs depending on the foundation pile. Moreover, it is difficult to stably mount the dividing drum on the foundation pile.

The present inventor has described a very simple method and apparatus,
We succeeded in eliminating this adverse effect. The loading test method for inspecting the supporting force of the foundation pile according to the present invention is as follows. The division cylinder 5 is placed on the foundation pile 1 in a state of being lifted by a crane, and the load obtained by subtracting the lifting force of the crane from the mass of the division cylinder 5 is applied to the foundation pile 1. And test the bearing capacity. For this reason, the load test method of the present invention can change the load of the foundation pile without using a large number of split cylinders.

[0008] For example, a 1500-ton separating cylinder is placed on a foundation pile in a state of being suspended by a crane, and the lifting force of the crane is adjusted to 500 tons.
A load of 0 tons is applied. This loading test method is 1500
The lifting force of the crane is 0 to 1
Adjust in the range of 500 tons and set the load acting on the foundation pile to 0
It can be adjusted freely between ~ 1500 tons.

Further, the loading device according to claim 2 of the present invention,
The base split cylinder 5A and the load split cylinder 5B are mounted so that various loads can be stably applied to the foundation pile 1. The base split cylinder 5A
A connection recess 7 is provided on the lower surface of the base pile 1 so that the upper end of the base pile 1 can be inserted into the base pile 1 so as to be placed in a balanced manner.
The load dividing cylinder 5B has a structure in which it is mounted on the base dividing cylinder 5A in a balanced manner so as not to move in a horizontal plane.
In this loading device, the base split cylinder 5A and the load split cylinder 5B are placed on the foundation pile 1, and the supporting force of the foundation pile 1 is inspected.

Further, in the loading device for inspecting the supporting force of the foundation pile 1 according to the third aspect of the present invention, the spacer 8 is fitted into the connecting recess 7 provided in the base dividing cylinder 5A. The base dividing cylinder 5A is mounted on the foundation pile 1 via the spacer 8.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples are intended to exemplify a loading test method and a loading device of a foundation pile for embodying the technical idea of the present invention, and the present invention includes the following loading test method and loading device. Not specific to

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”. However, the members described in the claims are not limited to the members of the embodiments.

The loading device shown in FIG. 3 for inspecting the supporting force of a foundation pile is composed of a base cylinder 5A placed on the upper end of a foundation pile 1 vertically driven into the ground, And a plurality of load dividing cylinders 5B stacked on each other.

The base dividing cylinder 5A and the load dividing cylinder 5B have a columnar shape having the same outer shape, and are manufactured by molding a steel casting or concrete. The load casting cylinder 5B made of a steel casting has, for example, an outer diameter of 6000 mm, a height of 4500 mm, and a mass of 10 mm.
00 tons. If the height is 450 mm with the same outer diameter, the mass becomes 100 tons.

The base dividing cylinder 5A and the load dividing cylinder 5B protrude from the outer periphery and have a plurality of hanging fittings 6 fixed to an upper end edge. The hanging bracket 6 connects a shackle and a wire rope (not shown) here, and lifts the base division drum 5A and the load division cylinder 5B with a crane (not shown) in a well-balanced manner, and places it on the foundation pile 1. For this reason, the hanging fittings 6 are provided at equal intervals. The hanging bracket 6 is a metal plate and has a through hole through which a shackle can be inserted. The hanging metal fittings 6 are partially buried and fixed to the base dividing cylinder 5A and the load dividing cylinder 5B. The number of hanging metal fittings 6 is adjusted by the mass of the base cylinder 5A and the load cylinder 5B. For example, a 1000 ton base separation cylinder 5A or a load separation cylinder 5B
As shown in FIG. 4, 16 hanging fittings 6 are fixed at equal intervals, 8 at 500 tons, and 4 at 200 tons or less.

The base dividing cylinder 5A has a connection recess 7 at the center of the lower surface thereof so that it can be stably mounted on the upper end of the foundation pile 1 with good balance. The connection recess 7 is opened in a columnar shape larger than the outer diameter of the thickest foundation pile 1 on which the base dividing cylinder 5A is placed. For example, a 500-ton base separation cylinder 5A opens a connection recess 7 having an inner diameter and a depth of about 1500 mm. The bottom surface of the connecting recess 7, and the upper surface of the connecting recess 7 in FIG. 3, is a horizontal surface so that it can be stably mounted horizontally on the upper end surface of the foundation pile 1. Base split cylinder 5
In A, the connection recess 7 can be deepened and stably mounted on the foundation pile 1. This is because, as the connection recess 7 is made deeper, the position of the center of gravity of the base division drum 5A with respect to the position where it is placed on the foundation pile 1 becomes lower.

The inner diameter of the connecting recess 7 is considerably larger than the outer diameter of the foundation pile 1 so that the base dividing drum 5A can be stably mounted on the foundation pile 1 having a different outer diameter without falling over. When it is large, as shown in the cross-sectional view of FIG.
A is placed on the foundation pile 1. The spacer 8 is cylindrical and has an outer diameter substantially equal to the inner diameter of the coupling recess 7. The inner diameter of the spacer 8 is set so that the foundation pile 1 can be inserted here.
It is almost equal to the outer diameter of the foundation pile 1. Further, the spacer 8 has a tapered opening at the lower end so that the spacer 8 can be quickly guided to the upper end of the foundation pile 1. The base separation cylinder 5A having this structure can be stably mounted on the upper ends of the foundation piles 1 having various outer diameters by exchanging the spacers 8. For example, as shown in the enlarged view of FIG. 3, the spacer 8 is attached to the base separating cylinder 5A via a fixing piece 11 fixed to the lower surface of the base separating cylinder 5A so as not to fall out of the connection recess 7. You.

The base dividing cylinder 5A is formed by stacking the load dividing cylinders 5B so as not to slide horizontally, with the upper surface being a horizontal plane. Further, the base separation cylinder 5A and the load separation cylinder 5B can be accurately stacked without positional deviation in a horizontal plane, and further, in the stacked state, the base separation cylinder 5A does not slide horizontally.
A positioning protrusion 9 is provided on the upper surface of A, and a positioning recess 10 into which the positioning protrusion 9 is fitted is provided on the lower surface of the load dividing cylinder 5B.
The positioning projection 9 is located at the center of the base dividing cylinder 5A,
Is provided at the center of the load dividing cylinder 5B,
Into the positioning recess 10, and the load cylinder 5B
A is laminated so as not to skid.

By the way, a plurality of load distributing cylinders 5 B are stacked, and the dividing cylinder 5 having a predetermined mass is placed on the foundation pile 1. The load dividing cylinder 5B to be laminated is provided with a positioning concave portion 10 on the lower surface and a positioning convex portion 9 on the upper surface so as not to skid. The positioning projection 9 of the load dividing cylinder 5B is formed in the same shape as the positioning projection 9 of the base dividing cylinder 5A. The loading device shown in the figure has a positioning projection 9 protruding from the upper surface, and a positioning recess 10 into which the positioning projection 9 is fitted is provided on the lower surface. However, the loading device has a positioning recess 10 on the upper surface,
The positioning protrusion 9 may be provided on the lower surface. Further, a plurality of positioning protrusions 9 and positioning recesses 10 can be provided so as to be fitted to each other.

In the loading device shown in the figure, a 1000 ton load cylinder 5B is placed on a 500 ton base cylinder 5A, and 200 ton, 100 ton and 5 ton are loaded on the load cylinder 5B.
0 ton and 10 ton load separating cylinders 5B are stacked. This loading device can load a total of 1860 tons on the foundation pile 1.

The above-described loading device is used in the following loading test method to check the bearing capacity of the foundation pile. At the upper end of the foundation pile 1, the base dividing cylinder 5A is suspended and placed by a crane. When the inner diameter of the connecting recess 7 is considerably larger than the outer diameter of the foundation pile 1 and the base separation cylinder 5A cannot be stably mounted on the foundation pile 1, as shown in FIG.
The base division cylinder 5A is placed on the foundation pile 1 via the spacer 8 inserted in the connection recess 7. The spacer 8 is a base separation cylinder 5A.
Is mounted on the connecting recess 7 of the base dividing cylinder 5A before being placed on the foundation pile 1. When the inner diameter of the connecting recess 7 provided on the base dividing cylinder 5A is substantially equal to the outer diameter of the foundation pile 1, the spacer 8
, The base cylinder 5A is placed directly on the upper end of the foundation pile 1.

When a support force test of the foundation pile 1 can be performed with the load of the base division drum 5A, the support force of the foundation pile 1 is tested in this state. Further, when performing a loading test with a load smaller than the mass of the base separating drum 5A, a shackle and a wire rope are connected to the hanging bracket 6 provided on the base separating drum 5A, and the wire rope is lifted by a crane and loaded. Test. The crane lifts the base drum 5A with a predetermined force, and performs a loading test of the foundation pile 1 with a load smaller than the mass of the base drum 5A. For example, when a loading test of 300 tons is performed on the foundation pile 1 using a 500 ton base separation drum 5A, the base separation drum 5A is lifted with a force of 200 tons and the base separation drum 5A is lifted. 5A is placed on the foundation pile 1. This method
By adjusting the lifting force of the crane, the load on the foundation pile 1 of the base dividing drum 5A can be adjusted in the range of 0 to 500 tons.

When the mass of the base separation cylinder 5A is smaller than the load test load of the foundation pile 1,
B is suspended and further placed on the base dividing cylinder 5A. 1
When the load for the loading of the foundation pile 1 is not obtained with the individual load splitters 5B, the load splitters 5B are further laminated. When the total mass of the base body 5A and the load body 5B becomes the load test load of the foundation pile 1, a load test is performed without lifting the load body 5B and the base body 5A with a crane.

The total mass of the base cylinder 5A and the load cylinder 5B is
When the load test load of the foundation pile 1 is larger than the load test load of the foundation pile 1 and the stacking number of the load cylinders 5B cannot be adjusted to be the load test load of the foundation pile 1, Laminate. Then, a shackle and a wire rope are connected to the hanging bracket 6 of the load drum 5B or the base drum 5A, and a load test is performed by lifting the wire rope with a crane. The crane lifts the base division cylinder 5A and the load division cylinder 5B with a predetermined force, and performs a loading test of the foundation pile 1 with a load smaller than the mass of the full division cylinder 5. The adjustment range of the loading test load of the foundation pile 1 can be changed by changing the load split cylinder 5B and the base split cylinder 5A that are lifted by the crane. For example, when the base separation drum 5A stacked at the lowest level is lifted by a crane,
The loading test load of the foundation pile 1 can be reduced to zero. When the uppermost load distributing cylinder 5B is lifted by a crane, the mass of the uppermost load distributing cylinder 5B can be reduced to zero. In general,
The load test load of the foundation pile 1 is adjusted by lifting the load separating cylinder 5B at the uppermost stage with a crane.

[0025]

The loading test method and the loading device for testing the supporting force of a foundation pile according to the present invention have the feature that the supporting force of the foundation pile can be inspected simply, easily, at low cost and efficiently.
That is, the loading test method of claim 1 of the present invention puts a separating cylinder directly on the foundation pile, inspects the supporting force of the foundation pile, and lifts the dividing cylinder with a crane to determine the state of mass of the dividing cylinder. This is because the load obtained by subtracting the lifting force of the crane can be applied to the foundation pile to check the supporting force.

Further, the loading device according to claim 2 of the present invention,
Inserting the upper end of the foundation pile, a base separation cylinder having a connection recess on the lower surface that can be placed on the foundation pile in a balanced manner,
A load balance which is mounted on the base body in a balanced manner so as not to move in a horizontal plane is provided. The base body and the load body are placed on the foundation pile to support the foundation pile. Since it is configured to check the force, there is a feature that the supporting force of the foundation pile can be quickly checked with an apparatus having an extremely simple structure.

Further, the loading device according to claim 3 of the present invention,
A spacer is placed in the connecting recess of the base cylinder and the base cylinder is placed on the foundation pile via this spacer, so that the base cylinder can be stably mounted on foundation piles of various outer diameters. There is a feature that can be.

[Brief description of the drawings]

FIG. 1 is a front view showing a conventional load test method for inspecting the bearing capacity of a foundation pile.

FIG. 2 is a front view showing another conventional load test method.

FIG. 3 is a partial cross-sectional front view showing a loading test method and a loading device for inspecting the bearing capacity of a foundation pile according to the present invention.

FIG. 4 is a plan view of a load dividing cylinder.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Foundation pile 2 ... Reaction force pile 3 ... Hydraulic jack 4 ... Girder 5 ... Separation cylinder 5A ... Base division cylinder 5B ... Load division 6 ... Hanging metal fitting 7 ... Connection concave part 8 ... Spacer 9 ... Positioning convex part 10 ... Positioning recess 11 ... fixed piece

Claims (3)

(57) [Claims] Claims 1. A loading test method for placing a separation drum (5) directly on a foundation pile (1) and inspecting the support force of the foundation pile (1), wherein the separation drum (5) is crane-mounted. As a lifting state,
(5) is placed on the foundation pile (1), and the load obtained by subtracting the lifting force of the crane from the mass of the separating cylinder (5) is loaded on the foundation pile (1) to check the bearing capacity. A loading test method for checking the bearing capacity of a pile. 2. Insert the upper end of the foundation pile (1), and insert the foundation pile (1).
A base separation cylinder (5A) having a connection recess (7) on the lower surface that can be placed on the base in a balanced manner, and on this base separation cylinder (5A), balance so as not to move in a horizontal plane. It consists of a load cylinder (5B) to be placed, a base cylinder (5A) and a load cylinder (5B).
B) is mounted on the foundation pile (1) to test the bearing capacity of the foundation pile (1). 3. A spacer (8) is fitted into the connecting recess (7),
3. The loading device according to claim 2, wherein the base pile (5A) is loaded on the foundation pile (1) via the spacer (8).