JPH0647812B2 - Detection method for defective parts in water-blocking sheets - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for detecting a defective portion of a waterproof sheet laid on the ground surface of a reservoir, a waste disposal site, or the like.

<< Prior Art >> A water barrier sheet is a sheet that is laid on the bottom ground such as a reservoir or a waste disposal site to prevent water from penetrating into the ground.

This waterproof sheet is made of synthetic rubber, synthetic resin, and other polymeric materials, as well as layered waterproof materials such as asphalt, rubber asphalt, and clay lining, and other sheet waterproof materials used for roofing. is there.

Therefore, the water-impervious sheet made of these water-impervious materials is used not in the form of a single sheet but in the form of being joined vertically and horizontally through the joint portion.

Therefore, if the treatment of the joint portion is inappropriate, there is a risk that water will leak from here, and also the seat itself may be broken by external force during laying and leak water.

Therefore, after laying the seat and constructing the joint, it is necessary to inspect the defective location and repair it before using it.

Conventionally, this inspection method mainly involves visual inspection to check for damage, or to apply pressure above atmospheric pressure to the joint to check for leaks, or vice versa. There was a method of checking for leaks, and a method of pulling out the specimen and inspecting it for water leakage by an indoor test.

<< Problems to be Solved by the Invention >> However, the inspection method based on the visual recognition is not reliable, and the method for inspecting for leakage by observing the atmospheric pressure fluctuation can only perform a partial inspection because of the facility. In the inspection of the specimen, it was the same as the sampling inspection, and it was not possible to perform an inspection that completely covered an extremely large whole part.

The present invention has been made in view of the above points, and an object thereof is to provide a method capable of simultaneously and easily inspecting a large water-impervious area including the water-impermeable sheet itself and its joint.

<< Means for Solving the Problem >> In order to achieve the above-mentioned object, the present invention is a method for detecting a defective portion of a water-impervious sheet laid on the ground, and a lower portion of the water-impermeable sheet and a ground surface during construction. While interposing a ventilation layer consisting of a breathable member in advance, after blowing the water-permeable sheet and the completion of the joint portion, gas is blown into the gas-permeable layer, and the gas blow-out site on the surface of the water-permeable sheet is By detecting, the blown-out portion was specified as a defective portion.

<Operation> According to the above method, the gas blown into the ventilation layer is
Sprays on the sheet surface from defective parts such as damaged parts and defective joints in the water-blocking sheet.

Therefore, the defective portion can be specified by visually confirming the color of the ejected gas or by detecting the concentration of the gas by the mechanical detection means.

<< Embodiment >> An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 and FIG. 2 show a first embodiment when the method of the present invention is applied to a method of detecting a defective portion of a water-blocking sheet at a waste final disposal site provided in a valley.

In the figure, this waste final disposal site is dammed at the exit end by an artificially constructed dam 1, and the slope A of this dam is
It is built on the bottom ground E in the shape of a mortar surrounded by the slopes B of the Tanizawa area, which are constructed on three sides naturally or artificially.

As the construction method, the ventilation layer 2 made of a breathable member is continuously laid on the bottom ground E and the slope B before the dam 1 is constructed.

The ventilation layer 2 is made of a resin such as a hard vinyl chloride pipe or a polyethylene pipe having a perforated pipe made of a resin, a perforated pipe made of concrete, a pipe made of a concrete underdrain, a pipe made of vinyl chloride, a resin such as polyethylene. It is possible to select an underdrain drainage material, a non-woven fabric called a so-called suction preventive material, a gravel with good water permeability, or a combination thereof.

For example, as shown by the chain line in FIG. 1, a plurality of perforated pipes 2a are laid from the lower side of the dam 1 toward the opposite slope B in accordance with the topography of the valley valley to form a tortoiseshell shape, and the space between them is laid. The ventilation layer 2 is formed by an operation such as filling with gravel.

Next, the dam 1 is constructed by embankment or the like, and the outlet end of the valley is blocked.

Finally, the water blocking sheet 3 is continuously laid on the upper surface of the ventilation layer 2 to cover the slope 1 of the dam 1.

Of course, this water-impervious sheet 3 is not a single piece, but is made by integrally sizing the above-mentioned standard-sized sheets of various water-impervious materials vertically and horizontally, and its joint portion is not shown. It is airtightly joined by a chemical, heat fusion or mechanical fasteners.

After the above construction work is completed, the waterproof sheet 3 is inspected.

In this inspection method, the end of the perforated pipe 2a exposed at the end of the ventilation layer 2 which is exposed outside the lower part of the dam 1 is used as a smoke inlet to blow smoke, which is one kind of gas, from here. Done by

Smoke flows inside the ventilation layer 2 along the direction of the arrow in the figure, and escapes when it reaches the top end of the facing slope B, and this state is confirmed by the smoke rising at the edge of the water shield sheet 3.

Then, as shown in the figure, if any part of the water-blocking sheet 3 is broken or there is a defective joint, smoke rises from the defective portion 3a, and the defective portion 3a is identified by visual confirmation. You can do it.

Since the defective portion 3a is a place where smoke that has filled the inside of the ventilation layer 2 escapes, no matter where the water-blocking sheet 3 is, it can be visually checked immediately even if the water-blocking sheet 3 has a large area. .

Therefore, it can be used as a final waste disposal site after repairing the defective portion 3a.

FIGS. 3 and 4 show the case where the present invention is applied to a digging type reservoir, in which the bottom ground E of a rectangular reservoir formed by excavating the ground 10 in an inverted trapezoidal shape and On the slope C, the ventilation layer 2 made of the same breathable material as that described above is laid in advance, and the water blocking sheet 3 is laid on the upper surface of the ventilation layer 2 to complete the construction of the reservoir.

After the construction is completed, smoke is blown by the same procedure as above to identify the defective portion. In this case, a smoke blowing port 3b is opened at the center of the bottom surface of the water-blocking sheet 3, and the smoke is vented from this layer 2 It is blown into the perforated pipe 2a buried inside.

The blown smoke flows in all directions along the inside of the ventilation layer as indicated by the arrow in the figure, and is discharged from the entire circumference of the edge of the water-blocking sheet 3.

If there is a defective portion 3a, smoke rises from this portion and the defective portion can be immediately identified.

After the inspection is completed, the defective portion 3a and the smoke inlet 3b can be repaired to be used as a reservoir.

Although smoke was blown as the detection method of the present invention in each of the above-described embodiments, other colored gas, rare gas, or the like can be used. Further, when a rare gas is used, a defective portion can be specified by using a dedicated gas detector.

<< Effects of the Invention >> As described in detail above with reference to the embodiments, the method of detecting a defective portion in the water-blocking sheet according to the present invention has the following effects.

The gas blown into the breathable layer after the completion of the construction is jetted from the defective portion such as the damaged portion or the defective joint portion in the water-impermeable sheet to the surface of the sheet.

Therefore, in the method of the present invention, by visually confirming the color of the gas to be ejected or by detecting the concentration of the gas or the like by a mechanical detection means, the defective portion can be immediately specified,
A large impermeable area including the impermeable sheet itself and its joint can be detected simultaneously and easily.

[Brief description of drawings]

FIG. 1 is a plan view when the present invention is applied to a final waste disposal site, and FIG. 2 is a sectional view taken along the line II-II in FIG.
FIG. 4 is a plan view showing a case where the present invention is applied to a digging type reservoir, and FIG. 4 is a sectional view taken along line IV-IV in FIG. 1 ... Dam, 2 ... Ventilation layer 2a ... Perforated pipe, 3 ... Impermeable sheet 3a ... Missing part, 3b ... Smoke inlet 10 ... Ground, E ... Ground A, B ... … Slope

Claims (1)

[Claims] 1. A method for detecting a defective portion of a waterproof sheet laid on the ground, wherein a ventilation layer made of a breathable member is previously interposed between the lower portion of the waterproof sheet and the ground surface during construction. In addition, the gas is blown into the ventilation layer after the laying of the waterproof sheet and the construction of the joint portion are completed, and the blown-out portion of the gas on the surface of the waterproof sheet is detected to identify the blown-out portion as a defective portion. A method for detecting a defect in a water-blocking sheet, characterized in that