JP7659264B2 - Strength test method and strength test device for earth and sand barrier structures - Google Patents

Description

The present invention relates to a method for testing the strength of landslide prevention structures, with the aim of preventing fatal and injury accidents involving workers caused by landslides during trench excavation work or work inside a trench, and to a strength testing device used for said strength testing.

In water supply and sewerage construction work involving small-scale trench excavation work, retaining supports may be installed prior to work in the trench to prevent industrial accidents caused by landslides during trench excavation work and work inside the trench.

Specifically, excavation (unlined digging) is done using a drag shovel, then lightweight steel sheet piles are erected so as to be attached to the excavated surface, and the wales and struts are attached to assemble the retaining support structure.

The applicant of this application has proposed a sediment blocking device as described in Patent Document 1 in order to prevent industrial accidents caused by the above-mentioned landslides.

Patent Publication No. 6431239

However, there are no established unified standards for the strength test method of the above-mentioned earth retaining support structures and the earth retaining device described in the above-mentioned Patent Document 1. This may lead to a situation where tests are conducted using various methods, and if so, the test results obtained may not be considered absolute evaluations. In the following description, the earth retaining device described in Patent Document 1 will be referred to as the earth retaining device. In addition, in the present invention, the earth retaining support structures, panel earth retaining structures, and other earth retaining devices including this earth retaining device will be collectively referred to as the earth retaining structure. The present invention relates to a strength test method and strength test device for this generic earth retaining structure.

The strength testing method previously used by the applicant involves piling up soil next to the soil barrier structure and allowing it to collapse naturally to check whether the soil barrier structure can withstand the force.

However, this testing method has drawbacks, such as the need for large-scale equipment and the difficulty of applying a quantitative load.

The present invention aims to provide a strength testing method and strength testing device for a sediment barrier structure that allows for confirmation of strength in a relatively simple manner without the need for extensive landslide experiments, and that allows for more quantitative loading than the method of piling up and collapsing sediment.

The configuration of the present invention to achieve the above objective is as follows:

(1) The strength test device for earth and sand blocking structures described in claim 1 is composed of a base portion, a rail member, and a weight.

(2) The strength test device for earth and sand barrier structures described in claim 2 is configured in the invention described in claim 1 using a ground leveling roller as a weight.

(3) The strength test device for soil and sand barrier structures described in claim 3 is the invention described in claim 2, in which the weight of the weight is made variable by packing a weight inside the cylindrical body that constitutes the ground leveling roller.

(4) The method for testing the strength of a sediment barrier structure according to claim 4 is carried out by impacting a weight against the sediment barrier structure using a strength testing device according to any one of claims 1 to 3.

How the present invention configured as described above works to solve the problems will be generally explained with reference to the drawings. Note that in each figure, U means up, D means down, R means right, and L means left.

Figure 2 is an explanatory diagram showing an embodiment of a method for testing the strength of a sediment-blocking structure (hereinafter referred to as the strength test method) using the strength test device for sediment-blocking structures (hereinafter referred to as the strength test device) described in claim 2 or claim 3. As shown in the figure, a simulated groove is reproduced between an L-shaped concrete retaining wall 2 and a base 10, and a sediment-blocking device 1 is installed between them.

A rail member 20 is stretched between the left and right base portions 10, and the leveling roller 30 is dropped along the rail member 20 by its own weight, colliding with the soil blocking device 1.

According to the present invention configured as described above, the weight and volume of the leveling roller 30 can be set in advance, and by measuring the speed of the leveling roller 30 at the time of collision, the energy at the time of collision can be accurately calculated.

In this way, the present invention makes it possible to check strength using a relatively simple method, and also makes it possible to apply a quantitative load.

Perspective view of strength test device FIG. 1 is an explanatory diagram showing an embodiment of a strength test method. Graph showing the relationship between sheet tension and elapsed time Graph showing the relationship between bending moment of diagonal members and elapsed time

Below, preferred embodiments of the invention will be described with reference to the drawings. Note that the embodiments of the components of the present invention are not limited to the following embodiments, and various forms may be adopted as long as they fall within the technical scope of the present invention. In addition, the same reference numerals are used to describe the components that are common to each claim.

Figures 1 and 2 show the strength testing device described in claim 2 or claim 3. The pedestal portion 10 in the figure is used to incline the rail member 20, and as shown in Figure 2, there is a pedestal portion 10a installed on the underside of the rail member 20 near the soil blocking device 1, and a pedestal portion 10b installed on the underside of the opposite end of the rail member 20. In order to incline the rail member 20, the height of the pedestal portion 10a is set to be lower than the height of the pedestal portion 10b.

These bases 10 are made of plastic pallets used in logistics and other fields. The height of the bases 10 can be adjusted by changing the number of pallets stacked on top of each other. Of course, this is just one example, and the bases 10 can be made of timber or other materials as long as they can withstand the weight during testing, and a jack can be used to make the bases 10 adjustable in height.

As shown in FIG. 1, the rail member 20 is constructed by fixing a pair of long steel members 20a, 20a with a number of short steel members 20b.... The steel members 20a, 20b can be H-shaped steel or the like.

The leveling roller 30 is composed of a main body 31, a cylinder made of steel or stainless steel plate filled with a weight such as concrete, and a handle 32, such as an iron pipe. In the invention described in claim 3, the inside of the main body 31 is made hollow, and it is structured so that it can be filled with a heavy object to reach a set weight.

In addition, if a stopper 21, which is a protrusion, is provided at the end of the rail member 20, the leveling roller 30 can be fixed in place by engaging the handle 32 with the stopper 21, making it very easy to use.

In the invention described in claim 1, the weight falls under its own weight along the rail member and collides with the sediment blocking structure. In addition to the leveling roller 30, a steel ball or the like can be used as the weight. The rail member can also be of a shape that allows the weight to fall, such as a steel plate with grooves.

The method for testing the strength of a sediment barrier structure described in claim 4 is carried out by using the strength testing device described in any one of claims 1 to 3 to collide a weight against the sediment barrier structure. A specific example will be described in detail below with reference to Figure 2.

The base 10a is placed 0.8 m away from the L-shaped concrete retaining wall 2, recreating a trench 3 between the two, which is intended to be an excavation trench. The soil blocking device 1 is installed in this trench 3.

The weight of the leveling roller 30 is 3.1 kN and its volume is 0.196 ^m3 . Therefore, the unit volume weight is 15.72 kN/ ^m3 .

In the collision test, the handle 32 of the ground leveling roller 30 was engaged with the stopper 21 provided on the rail member 20. At this time, the height of the rail member 20 in contact with the ground leveling roller 30 was 0.9 m, and the total value including the diameter of the main body 31 of the ground leveling roller 30, 0.5 m, roughly coincides with the depth of the excavated trench, 1.5 m, in which the soil blocking device 1 is to be installed.

Under these conditions, the handle 32 was pushed up with a jack to release the leveling roller 30, causing it to fall under its own weight along the rail member 20 and collide with the soil blocking device 1.

At this time, strain gauges were attached to the beam 1a and diagonal member 1b of the soil blocking device 1 using the two-side active gauge method, making it possible to measure the tension of the sheet 1c acting on the beam 1a and the bending moment acting on the diagonal member 1b. In addition, LED lighting for image analysis was attached to the axle portion 31a of the soil leveling roller 30, and the collision was filmed with a high-speed camera. The speed of the soil leveling roller 30 at the time of collision with the soil blocking device 1 was determined by analyzing this filmed video. This makes it possible to calculate the energy at the time of collision.

Figures 3 and 4 show data measured using the above conditions and methods.

As shown in FIG. 3, the maximum tension applied to the sheet 1c on the side where the leveling roller 30 collides is 6.522 kN/m.

As shown in Figure 4, the maximum bending moment of the diagonal member 1b was 1.071 kN·m on the side where the leveling roller 31 collided, and 1.216 kN·m on the side of the L-shaped retaining wall 2.

The above example relates to strength testing of a sediment blocking device, but if a retaining support structure or a panel retaining structure made of a pair of panel members supported by struts is installed instead of the sediment blocking device, it will be possible to conduct strength testing of these support structures.

10: Base portion 20: Rail member 21: Stopper 30: Leveling roller 31: Main body 32: Handle

Claims (4)

A strength testing device for conducting a strength test of a soil blocking structure,
A strength testing device for soil and sand barrier structures, comprising two base sections of different heights , a rail member for spanning the two base sections , and a weight using a ground leveling roller attached to one end of the rail member . The strength testing device for soil and sand barrier structures according to claim 1, in which the weight of the weight is variable by packing a heavy object inside the cylindrical body constituting the ground leveling roller. The strength test device for a soil blocking structure according to claim 1, wherein the rail member has a stopper for retaining the soil leveling roller. A method for testing the strength of a sediment-blocking structure, comprising: using the strength testing apparatus according to any one of claims 1 to 3 to drop the weight along the rail member suspended on the two pedestal portions having different heights, thereby causing the weight to collide with the sediment-blocking structure.

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