JPH0584360B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to waterproof structures such as tunnels.

Conventional technology and problems to be solved by the invention Conventionally, for example, in tunnel waterproofing work such as the NATM construction method, a plastic sheet integrally formed with non-woven fabric was used, as seen in Publication of Utility Model Publication No. 51-37844. Although spring water is discharged from underground, when used for a long period of time, there is a problem that the earth and sand contained in the spring water adheres to the nonwoven fabric, reducing water permeability and waterproof performance.

Therefore, in order to strengthen the water permeability, the applicant proposed a method to increase the amount of water permeation by partially attaching a nonwoven fabric and a plastic sheet.
It has been proposed in the Publication No. 1 and other publications.

However, when these waterproof sheets are used in tunnels for a long period of time, there is a risk that earth and sand in spring water may enter the nonwoven fabric and reduce water permeability.

The present invention was made to improve the above-mentioned situation, and provides a waterproof structure for tunnels, etc. that effectively prevents dirt from entering the nonwoven fabric and exhibits excellent water permeability over a long period of time. The purpose is to

Means and Effects for Solving the Problem That is, in order to achieve the above object, the present invention provides a waterproof structure that waterproofs spring water in a tunnel or the like by disposing an impermeable sheet at a spring water outlet location in a tunnel or the like. A porous water-permeable sheet with air permeability and flexibility is placed between the spring water gushing point and the water-impermeable sheet, and a large number of fine particles with pores smaller than the water-permeable sheet are attached to the surface of the water-permeable sheet. A composite sheet for civil engineering comprising a synthetic resin film having holes is interposed such that the synthetic resin film is placed on the spring water outlet side and the water permeable sheet is placed on the impermeable sheet side. Provides waterproof structures such as tunnels, etc., characterized by:

In the waterproof structure of the present invention, a synthetic resin film having a large number of micropores is laminated on the surface of the water-permeable sheet, and this film acts as a filter to remove sediment from the spring water. Only water and fine earth and sand pass through the film and flow into the water-permeable sheet, without passing through the film and being removed outside the composite sheet. Therefore, in the waterproof sheet of the present invention, the sediment in the spring water does not enter the sheet, and therefore, during long-term use, the sediment accumulates on the sheet and blocks the spring water passage, reducing the water permeability of the sheet. This means that a decrease in the

In this case, in the present invention, the water-permeable sheet and the synthetic resin film having a large number of micropores disposed over the water-permeable sheet have the pore diameter of the latter smaller than the mesh pores (pore diameter) of the former. Accordingly, the object of the present invention can be satisfactorily achieved. Here, the water-permeable sheet is preferably a woven fabric, non-woven fabric, felt, or net-like sheet made of natural fiber or synthetic resin fiber with a thickness of about 1 to 5 mm, a synthetic resin sheet with many through holes, and others. Although various water permeable sheets can be used, it is particularly preferable to use nonwoven fabric. In addition, there are no restrictions on the material or properties of the synthetic resin film that has a large number of micropores, as long as it allows only water to pass through without allowing dirt to pass through, but preferably fine pores with an average diameter of about 5 to 20 μm are suitable. A film made of polyethylene, polypropylene, etc. having a large number of holes and having a thickness of about 5 to 50 μm is preferably used.

Examples of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following examples.

Embodiment The drawing shows a waterproof structure for a tunnel according to an embodiment of the present invention. In the drawing, 1 is the ground or primary lining concrete of the tunnel, 2 is an impermeable sheet, and 3 is a material interposed between these. This composite sheet 3 is made by thermally bonding a synthetic resin film 5 having a large number of micropores to one surface of a porous water-permeable sheet 4 having air permeability and flexibility. This composite sheet 3 is arranged with the film 3 located on the primary lining concrete 1 side (spring water inflow side), so that when spring water flows into the permeable sheet 4, the film 5 The filter action prevents earth and sand in the spring water from entering the water-permeable sheet 4.

Note that in the composite sheet 3 described above, the water-permeable sheet 4 and the film 5 are thermally bonded, but the bonding method is not limited to this, and a method using an adhesive may also be adopted. Furthermore, the waterproof structure described above can be adopted for embankment construction, and other configurations can be modified in various ways without departing from the gist of the present invention, such as bonding a water-permeable sheet and a synthetic resin film in a partial lattice shape. No problem.

Effects of the Invention As explained above, according to the waterproof structure of the present invention, a synthetic resin film having a large number of micropores is attached to the spring water inflow side of the water-permeable sheet as a filter for removing sand, so that spring water can This prevents sediment from entering the permeable sheet, and therefore prevents sediment from accumulating inside like conventional permeable sheets.
It is less likely to cause inconveniences such as blocking of spring water passages and deterioration of water permeability, and it is extremely effective in draining water from tunnel construction and embankment construction.

[Brief explanation of the drawing]

The drawing is a partially omitted sectional view showing a waterproof structure according to an embodiment of the present invention. 1... Primary lining concrete, 2... Impermeable sheet, 3... Composite sheet, 4... Permeable sheet, 5
...A synthetic resin film with many micropores.

Claims (1)

[Scope of Claims] 1. In a waterproof structure that waterproofs spring water from a tunnel, etc. by arranging an impermeable sheet at a spring water outlet in a tunnel, etc., between the spring water outlet and the impermeable sheet, A composite for civil engineering comprising a porous water-permeable sheet having breathability and flexibility, and a synthetic resin film adhered to the surface of the water-permeable sheet and having a large number of micropores with a smaller pore diameter than the water-permeable sheet. A waterproof structure for a tunnel or the like, characterized in that a sheet is interposed such that the synthetic resin film is placed on the spring water outlet side and the water permeable sheet is placed on the water impermeable sheet side. 2. The waterproof structure according to claim 1, wherein the porous water-permeable sheet is a nonwoven fabric. 3. The waterproof structure according to claim 1 or 2, wherein the synthetic resin film has micropores with an average pore diameter of 5 to 20 μm.