CN1328475C - Tunnel waterproofing method - Google Patents

Abstract

Provided is a waterproofing construction method with which excellent waterproofing capacity can be assured. A tunnel waterproofing method characterized in that a primary spray cement concrete is sprayed on the excavation surface of the tunnel, after which a waterproofing sheet having adhesiveness with a secondary coating cement concrete is installed on said primary spray cement concrete surface and a secondary coating cement concrete is established on said waterproofing sheet surface. A buffer-water conducting layer may also be established on said primary spray cement concrete surface and a multilayer waterproofing sheet having adhesiveness with the applied cement concete may also be installed as a waterproofing sheet.

Description

Tunnel Waterproofing Method

technical field

The invention relates to a method for waterproofing tunnels. In the present invention, slurry, mortar, and concrete are used as general terms representing cement concrete.

Background technique

Currently, the main tunnel construction method in Japan is the NATM method. The NATM construction method is a method in which a first coat is applied by spraying plaster or concrete directly after tunnel excavation to prevent rock fall and water leakage in the excavated area. Afterwards, a second concrete coat is applied in order to stabilize the tunnel by maintaining its strength. At this time, a waterproof sheet is provided for waterproofing and as an interlayer between the first concrete coat and the second concrete coat, so that water can be prevented from leaking into the tunnel, and adhesion due to the second concrete coat can be prevented. To induce cracks in a mound, or to prevent cracks due to migration of that mound. Recently, tunnel excavation can be performed by a tunnel boring machine (TBM construction method), and a waterproof sheet is provided for the same waterproofing purpose.

In addition, since the width of the sheet is narrow, such as 1-2 meters, there is a problem that when the ends of the waterproof sheet are stacked on each other and connected by welding, it requires more labor and labor and is not economical.

There is also a problem that water seepage is caused between the waterproof sheet and the second concrete coating due to functional damage of the waterproof sheet by poorly welded parts, and irregularities in the surface of the tunnel excavation, so that waterproofing ability cannot be obtained.

Contents of the invention

When the thickness of the waterproof sheet is increased in order to prevent the damage of the waterproof sheet, there is a problem that welding of the ends of the waterproof sheet becomes difficult and the mass of the waterproof sheet is increased, with the result that practical characteristics become worse.

The present inventors conducted various studies on the above-mentioned problems. As a result, they found a tunnel waterproofing construction method and perfected the present invention, in which a waterproof sheet having adhesion to the second coating cement concrete layer is placed on the first spray cement concrete layer before setting the second coating cement concrete layer. on the surface of the concrete layer, and wherein, by making the waterproof sheet integral with the second coated cement concrete layer, damage to the waterproof sheet and the second coated concrete layer due to poor welding positions and damage to the ends of the waterproof sheet is prevented. Water leakage in between, even when cracks occur in the second coated cement concrete layer, can prevent water leakage, and can greatly improve the waterproof ability.

The present invention particularly provides a method for tunnel waterproofing, characterized in that the first cement concrete layer is sprayed onto the surface of the tunnel cavity, and the waterproof isolation layer is set on the surface by adhering non-woven fabrics, fiber materials or irregular-shaped thin sheets. On the surface of the first cement concrete layer, a waterproof membrane is arranged on the waterproof isolation layer, the waterproof membrane has a plastic or rubber sheet and a second coating for adhesion coating on the waterproof membrane an adhesive layer of the cement concrete layer, and a second coated cement concrete layer is sprayed onto the waterproof membrane, thereby obtaining the waterproof tunnel.

Embodiments of the present invention

Hereinafter we will describe the present invention in detail.

The present invention is a construction method in which the waterproof sheet and the tunnel are integrally formed by spraying, preferably quick-drying cement concrete is sprayed onto the surface of the dug tunnel, after which a waterproofing sheet with adhesion to the second coated cement concrete layer is provided. Flakes. The waterproof sheet can adjust accordingly to the cracking of the cement concrete caused by the drying and shrinkage of the second coated cement concrete layer and the mound after completion. By integrating the cement concrete and the waterproof sheet, even if the waterproof sheet is damaged, contact with water occurs only at the damaged position. For this reason, as long as cracks in the second coating concrete in the damaged area of the waterproof sheet do not develop, water leakage does not occur. Therefore, water leakage is greatly reduced and excellent waterproofing ability can be obtained. In addition, due to water seepage between the waterproof sheet and the second coated cement concrete layer, damage to the waterproof ability of the tunnel as a whole, and cracks in the second coated cement concrete layer, when using conventional waterproofing Leakage does not occur when flakes. In addition, since the waterproof sheet integrally formed with the second coating cement concrete layer has good follow-up ability and does not cause damage even when the tunnel itself cracks, thereby preventing water leakage, Compared with the traditional waterproof construction method, the waterproof ability is greatly improved.

Examples of the waterproof sheet having adhesion to the second coated cement concrete layer include non-crosslinked rubber sheets such as isoprene rubber and natural rubber.

The waterproof sheet having adhesion to the second coated cement concrete layer may further contain an antioxidant, an ultraviolet radiation absorber, and an adhesive.

In the present invention, if the second coating cement concrete layer has been bounded by the mound, from increasing the insulating effect with the second coating cement concrete layer, it is hoped that the layer having adhesion with the second cement concrete layer and Polymer sheet lamination. When using a one-layer waterproof sheet having adhesiveness to the second coated cement concrete layer and a multi-layer waterproof sheet laminated with the polymer sheet, they are arranged so that the surface side of the first sprayed cement concrete layer is in contact with the polymer sheet , and the second coated cement concrete layer is provided to the surface side of the waterproof sheet having adhesion to the second coated cement concrete layer.

Examples of polymer sheet materials may include high density polyethylene, low density polyethylene, ethylene vinyl acetate (EVA), and polypropylene. Among these materials, high-density polyethylene is preferably used in terms of insulating effect, strength, crack follow-up ability, and price.

In the present invention, in order to improve the insulating effect, reduce the water pressure at these locations where a large amount of groundwater exists and increase the waterproofing effect, an insulating water-conducting layer can be formed before setting a waterproof sheet with adhesion to the second coating cement concrete layer . Examples of waterproof barriers may include layers formed by spraying fibrous substances such as fibrous pulp non-woven fabrics and sheets or irregularities such as polyester fibers and polypropylene.

It is possible to use a waterproof construction method in the bed portion of the tunnel, which shows high efficiency in preventing water leakage of the bed portion.

There is no particular limitation on the method of fixing the waterproof sheet, non-woven fabric and irregularities to the surface of the first sprayed cement concrete layer, and adhesives and rivets may be used.

After the waterproof sheet having adhesion to the second applied cementitious concrete layer has been provided in this manner, the second applied cementitious concrete layer can be applied and the construction completed.

example

In the following we will illustrate the present invention on the basis of examples.

example 1

A U-shaped mock tunnel was fabricated with an opening of 4m, a height of 3.5m and a length of 3m. It is assumed that the tunnel mound surface is irregular in the simulated tunnel, and 15 concrete blocks having a width of 15 cm, a height of 20 cm, and a length of 20 cm are arranged at appropriate intervals to form the irregular surface.

The quick-drying plaster was used as the first spray plaster layer and sprayed so that the quick-drying stucco was 10 cm thick.

After spraying, the multi-layer waterproof sheet (manufactured by Grace Construction Products Company of the United States, brand name Preprufe300; a double-layer sheet includes two layers, which is adhesive to the concrete layer) is attached to the second coating concrete layer by rivets. Adhesive, one layer of polyethylene; 2.7 mm thick) fixed to the surface of the first spray plaster layer. Afterwards, a second layer of coated concrete was applied to a thickness of 30 cm. In order to simulate damage to a multi-layer waterproofing sheet, a cut is made in a part of it.

28 days after the formation of the second coated concrete layer, a test sample was cut out by drilling and checked for adhesion to concrete. The second coated concrete layer and the waterproofing sheet are in good contact and become a whole. The peel strength of the second coated concrete layer and the waterproof sheet is greater than 0.9 N/mm.

Integrality with the second applied concrete layer was also maintained well in the area of the cutout, the cutout of the concrete being in the shape of a linear profile of less than 2 mm. Apply a static water pressure of 60m in the trench between the first sprayed concrete and the multi-layer waterproof sheet. However, water does not enter the groove between the multi-layer waterproof sheet and the second coated concrete layer, showing good waterproof ability.

Since the multilayer waterproof sheets used have adhesive properties, the multilayer waterproof sheets can be satisfactorily bonded to each other only by overlapping the end portions of the multilayer waterproof sheets. For this reason, its workability is excellent, and an ideal value of 1.7 N/mm in the bonding strength of the superimposed portion can be obtained.

To simulate cracks in a tunnel, the second coated concrete layer is stressed and cracked. No abnormalities were found in the multi-layer waterproofing sheet.

The following are test methods for various physical properties.

Adhesion strength to concrete: According to ASTM D 903 (90 degree peel strength). Adhesion strength of superimposed parts: according to ASTM D 1876 (determination in case of superimposed multi-layer waterproof sheets).

Example 2

Execute the same procedure as Example 1, except that the multi-layer waterproof sheet that is used and the second coating concrete layer has adhesion is the product of "Santacker Sheet" (isoprene rubber waterproof sheet, Lined nonwoven fabric product, manufactured by HayakawaRubber Corporation).

28 days after the formation of the second coated concrete layer, a test sample was cut out by drilling and checked for adhesion to concrete. The second coated concrete and the waterproofing sheet are in good contact and become a whole.

However, it is difficult to join the ends of the multi-layer waterproof sheet in scale 1, and workability is also a little difficult.

Comparative example 1

The same procedure as in Example 1 was carried out, except that a waterproof sheet made of EVA (which had no adhesion to the second coated concrete layer) was used instead of a multilayer sheet having adhesion to the second coated concrete layer. layer of waterproof sheet.

When a pressure equivalent to 30 m of static water pressure is applied to the trench between the first sprayed concrete layer and the multi-layer waterproof sheet, a large amount of water enters the multi-layer waterproof sheet and the second coating can be found from cracks where damage is assumed. In the trench between the concrete layers, and did not achieve the performance of the waterproof sheet.

Invention effect

By using the waterproof sheet having adhesiveness with the second coated cement concrete layer of the present invention so that the second coated cement concrete layer and the waterproof sheet are integrally formed, even if a part of the waterproof sheet is damaged, water does not enter the waterproof sheet In the trench between the second coat of concrete and the second coat of concrete, ensure good water resistance.

In addition, the waterproof sheet of the present invention has a good ability to follow the cracks, even if the cracks in the second coated cement concrete layer expand, the waterproof sheet will not be damaged, ensuring good waterproof ability. Even if the crack width is large and the waterproof sheet is damaged by any chance, since the other parts of the waterproof sheet and the second coated cement concrete layer are integrated, water will not seep into the waterproof sheet and the second coated concrete layer In the trench between; therefore, the industry is of great use.

Claims (9)

1. A method for waterproofing tunnels, characterized in that the first cement concrete layer is sprayed onto the surface of the tunnel cavity, and the waterproof isolation layer is set to the first cement by adhering non-woven fabrics, fiber materials or irregular-shaped thin sheets. On the surface of the concrete layer, a waterproof membrane is arranged on the waterproof isolation layer, the waterproof membrane has a plastic or rubber sheet and a second coating cement concrete layer for adhesion coating on the waterproof membrane Adhesive layer, and the second coated cement concrete layer is sprayed on the waterproof membrane, thereby obtaining the waterproof tunnel. 2. A kind of tunnel waterproofing method as claimed in claim 1, is characterized in that, described waterproof film has polymer sheet, and described polymer sheet can comprise high-density polyethylene, low-density polyethylene, ethylene-vinyl acetate copolymer material, polypropylene or their mixtures. 3. A tunnel waterproofing method as claimed in claim 1, characterized in that said sheet comprises non-cross-linked rubber. 4. A kind of tunnel waterproofing method as claimed in claim 3, is characterized in that, described non-crosslinked rubber sheet comprises isoprene rubber, natural rubber or its mixture. 5. A tunnel waterproofing method according to claim 1, characterized in that said waterproof film is formed by stacking ends of waterproof sheets. 6. A tunnel waterproofing method according to claim 1, characterized in that the setting of the waterproof isolation layer includes spraying fibrous substances. 7. A tunnel waterproofing method according to claim 1, characterized in that the setting of the waterproof isolation layer comprises spraying fibers comprising polyester, polypropylene or a mixture thereof. 8. A tunnel waterproofing method according to claim 1, characterized in that the setting of the waterproof isolation layer comprises using adhesives or rivets to adhere non-woven fabrics. 9. A tunnel waterproofing method according to claim 1, characterized in that the tunnel is a U-shaped tunnel.