JPH0454772B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a construction method for burying a structure in the soil, and more specifically, a construction method for burying a structure in the soil using a water-absorbing and swelling polymer material or an earthen material mixed therewith. The present invention relates to a water-stop lining method that can prevent the formation of voids in the reclaimed soil around the structure by erecting and backfilling the structure.

Therefore, although not particularly limited, the present invention is a construction method suitable for burying sluice gates, sluice pipes, etc.

[Prior Art] For example, a sluice gate or a sluice pipe is a structure whose main body is buried within an embankment and is a water control facility installed across a river or waterway, and at the same time constitutes a part of an embankment. These structures buried in the soil are
Due to differences in the characteristics of their supporting structures and materials, gaps often form between them and the surrounding soil, and cracks and loosening occur in the surrounding soil.

Water easily infiltrates into such gaps and slacks, and if these become connected as water channels, it can seriously impede the functionality of the above-mentioned irrigation structures and pose a danger. .

In order to prevent loosening or cracking around structures buried in the ground, backfilling with relatively fine-grained soil and compacting the soil well to provide low permeability and strength is effective. When relative displacement of the soil occurs, shear cracks occur in the soil, and the more compacted the soil is, the more clear openings are left and the more likely it is that water will form. Since such openings are made of soil containing fine-grained soil and are irregular in shape, it is impossible to treat them by methods such as compaction, filling, and pouring.

In addition, with conventional technology, it is said that significant cavity formation can be prevented by changing the foundation type of the structure or by implementing improvements that reduce the amount of subsidence in soft ground. Construction is also underway.

Furthermore, for gaps and water holes along the exterior walls of structures buried in the ground, we can repair them by drilling holes and injecting filler from inside the structure, or by injecting filler and permeable materials from above ground into the surrounding area of the structure. It is being done.

[Problems to be solved by the invention] In the prior art, even if the foundation type of the structure is changed or improvements are made to reduce the amount of subsidence in soft ground, relatively small subsidence of the ground or dam body soil Due to compression, earthquakes, traffic vibrations, and fluctuations in river water levels and groundwater levels, gaps tend to form near the contact surface between the structure and the embankment soil, and if the displacement is large, shear loosening zones may occur in the soil. It is easy to form and become watery. In particular, embankments and backfill soil around structures need to be well compacted to increase their strength and water-tightness, so when displacement occurs, the soil moves as clods, and conversely, gaps occur and remain. There are some easy drawbacks.

Furthermore, in repair work that involves injecting various fillers into gaps and water holes that have already formed, the deformation of the soil and the occurrence of cracks progress over time. It has become difficult to respond because of the discrepancies.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to solve the problem even if voids, cracks, loosening, etc. occur due to considerable displacement around buried structures.
The surrounding material closes the area by its own action and ensures water-stopping properties, which prevents the development of water holes and prevents erosion and destruction of the structure. Therefore, it is an object of the present invention to provide a new water-stop wrapping construction method for underground structures that does not require any repair work such as void filling.

[Means for Solving the Problems] The present invention, which can achieve the above objects, has a method of absorbing water so as to surround the outer wall surface of the structure when backfilling an underground structure. This is a water-stop lining construction method for an underground structure that is constructed by lining and backfilling with a polymeric material that has the property of expanding and expanding, or a soil material containing it.

The water-swellable polymer material used here is:
These include the water-absorbing and swelling polymer compound itself, a composite obtained by blending it with a soft resin, rubber, etc., or a mixture thereof. However, materials should be selected that are stable without decomposition in the soil, and do not cause toxicity or other pollution problems when mixed with groundwater, etc. It is also possible to use a material in which fine particles of these water-absorbing and swelling polymer materials are mixed with earth and sand.

A water-absorbing and swelling polymer compound refers to a substance that absorbs water and swells from several times to 1,000 times its own weight, but does not dissolve in water.For example, a specific example is vinyl acetate-α,β-insoluble. Saponified saturated dicarboxylic acid ester copolymer, crosslinked product of modified isobutylene-maleic anhydride copolymer, polyacrylic acid (salt) polymer having a crosslinked structure, saponified starch-acrylonitrile graft copolymer or starch- Examples include, but are not limited to, acrylic acid (salt) copolymers. The water-swelling polymer compound may be used alone,
Two or more types may be mixed. Among them, vinyl acetate
Saponified acrylic acid ester copolymers have a high absorption capacity and excellent strength upon water absorption, and are also one of the most preferred because they have good weather resistance and no toxicity problems. Further, the soft resin or rubber composite compounded with a water-absorbing and swelling polymer compound is desirably adjusted so that it can absorb 2 to 300 times its own weight of water. Examples of the soft resin include ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer, ethylene-acrylic acid ester copolymer, ethylene-acrylate copolymer, vinyl chloride polymer, and vinyl chloride copolymer. , urethane resin, etc. Also, as rubber, butadiene gum,
Examples include isoprene rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber, epichlorohydrin rubber, natural rubber, and EPDM.

If there is groundwater in the surrounding area, it is sufficient to simply wrap it with the above-mentioned material, and if water is not constantly present in the surrounding area, it is sufficient to wrap it up and then pour water into it. When the buried structure is large-sized, it is desirable to adjust the amount of water-absorbing and swelling polymeric material mixed into the wrapping material located below in accordance with the earth pressure it is subjected to. The amount of the water-absorbing and swelling polymeric material is determined so that its swelling pressure remains at rest in the initial state after construction.

[Function] When the water-absorbing swelling polymer material is in the soil, its swelling pressure is equal to the static earth pressure. Therefore, after a structure is buried, it will remain in the same state as long as there are no stress changes or gaps in the soil.

However, when a gap is created near the contact surface of the structure and water enters the gap, the water-absorbing and swelling polymeric material existing in the portion facing the gap absorbs water and expands when the stress is released, closing the gap. As a result, the water-absorbing and swelling polymer material in the soil behind the soil gradually expands by a small amount, and the structural skeleton of the soil particles is slightly displaced toward the void side. By closing the gap with the expandable material in this way, it is possible to prevent the formation of water grooves and water leakage along the vicinity of the contact surface between the structure and the soil.

[Example] Hereinafter, the present invention will be explained in more detail based on the drawings. FIG. 1 is an explanatory diagram showing an embodiment of the construction method according to the present invention. The underground structure used here is a gutter pipe. Generally, gutter pipes are constructed underground by excavating the ground, forming it, and then backfilling it. First, to ensure water safety during the construction period, steel sheet piles, etc. will be driven in to create a temporary cofferdam in place of the river embankment. Then, the ground 10 is excavated in a cross section having a predetermined slope 12, and then foundation work is performed. The foundation of the gutter pipe is generally made of piles 14.
This is done by typing . A gutter pipe 16 will be formed on such a foundation pile 14.
The gutter pipe 16 is manufactured by pouring concrete for the foundation and then pouring concrete for the main body separately for the bottom slab, side walls, and top slab.

Now, as is clear from FIG. 1, the present invention is significantly different from the prior art in that the gutter pipe 16 is covered with a rolled material 18 that has water-absorbing and swelling properties, and is then backfilled with earth and sand 20. The point is to do this.

The material 18 that covers the outer periphery of the gutter pipe 16 is made of saponified vinyl acetate-acrylic ester copolymer mixed with styrene-butadiene rubber, which absorbs 50 times its own weight of water and expands. It is an earthy material made by mixing a finely grained polymer material with earth and sand. This rolling material 18
is designed so that the properties below and above the gutter pipe 16 are slightly different. That is, the winding material 18a located at the lower position, the winding material 18b located at the middle, and the winding material 18c located at the upper position are made of vinyl acetate-acrylic acid ester copolymer, which is a water-absorbing and swelling polymeric material, as the lower one is located. It is rolled up in a certain distribution so that the content of saponified substances is high. This is because the earth pressure increases as you move downward.
The amount of water-absorbing and swelling polymeric material mixed into the winding material 18 is adjusted so that its swelling pressure is approximately equal to static earth pressure.

After the material is rolled up, it is backfilled with earth and sand 20. This method of backfilling may be the same as that of the prior art, and is performed by making a layer of several tens of centimeters thick and ramming it symmetrically and uniformly so as not to apply uneven pressure.

After construction, if the water level WL is located above the upper end of the hoisting material 18, the infiltrating water is absorbed by the water-absorbing and swelling polymeric material in the hoisting material 18, and reaches the surrounding earth pressure and the level. expands to. After the gutter pipe is buried, it will remain as it is unless stress eruptions or voids occur in the soil. Relatively small ground subsidence, compression of embankment soil, earthquakes, traffic vibrations, fluctuations in river water level and groundwater level, etc., create gaps between the gutter pipes and backfill soil, causing displacement and loosening zones. When a water gap is formed, the water-absorbing and swelling polymeric material expands further due to the water penetrating through the gap, thereby closing the gap. In other words, if a void is created due to ground subsidence, etc., it will absorb the decrease in pressure and expand. The physical properties of the expanded water-absorbing and swelling polymer material are that it is an elastic body with a high amount of strain, and can sufficiently stop water. Therefore, after construction, it is possible to follow displacement that may occur over many years and constantly close the void, preventing the formation of water grooves and water leaks along the contact surface between the gutter pipe and earth and sand. It is possible to do so.

FIG. 2 is an explanatory diagram showing another embodiment of the burying method according to the present invention. Since it is basically the same as in FIG. 1, corresponding parts are given the same reference numerals and detailed explanation thereof will be omitted. The major differences between this example and the previous example are as follows:
The point is that the rolling material is filled in a wide range up to the excavated slope surface 12, and the water level WL is the same as that of the rolling material 18.
This is a point that can be used when the location is expected to be lower than the top of the . When the rolling material 18 is a mixture of a water-absorbing and swelling polymeric material and earth and sand, it is extremely easy to construct and compact the rolling material by spreading it widely as shown in Fig. 2. It is also preferable from the point of view. Water is injected into soil layers where there is no groundwater, causing water absorption and expansion. Then, the upper part of the rolled material 18 is covered with a sheet 22 having a gap, and the top is backfilled with earth and sand 20. As the sheet 22, a flexible sheet with corrosion resistance and a large number of holes is used to prevent water absorbed into the winding material 18 from evaporating and shrinking in volume. It functions to maintain the expanded state by allowing water leakage from above to some extent.

Since the filling of voids and the water-stopping effect of the winding material are exactly the same as those described in connection with FIG. 1, a description thereof will also be omitted.

Although two preferred embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not limited to only such configurations. Although the above embodiment is an example in which the present invention is applied to a gutter pipe as a structure buried in the ground, it goes without saying that the present invention can be applied to any other structure. In addition, as the winding material, an earthen material is used, which is a mixture of finely divided water-swelling polymer material and earth and sand, but the water-swelling polymer compound itself may also be used, or it can be combined with soft resin, rubber, etc. A mixture of these may also be used.

[Effects of the Invention] The present invention is a water-stop wrapping construction method for a structure buried in the ground constructed as described above, in which the periphery of the structure to be buried is wrapped with a water-absorbing and swelling polymeric material or an earthen material containing the same. Because of this structure, it absorbs surrounding moisture and is maintained in an expanded state with static earth pressure, and if voids, cracks, or loosening occur due to considerable displacement, the material itself will absorb water and expand. Since it is possible to block them and shut off water, it is possible to achieve the excellent effect of preventing erosion and destruction of structures due to cavity expansion.

In addition, in the present invention, the winding material itself expands in accordance with the expansion of the gap that occurs, and continues to block and stop water.
It is extremely effective in that it does not require repairs for a long period of time after construction, and does not require periodic inspection of voids, making it maintenance-free.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the water stop wrapping construction method according to the present invention, and FIG. 2 is an explanatory diagram showing another embodiment of the present invention. 10...Ground, 12...Slope, 14...Foundation pile, 16...Gutter pipe, 18...Winging material, 20...
...Earth and sand, 22...Sheet with gaps.

Claims (1)

[Scope of Claims] 1. A buried construction method in which the ground is excavated, foundation work is performed, a structure is installed on the foundation, and then backfilling is performed,
A water-stop wrapping construction method for a structure buried in the ground, characterized in that backfilling is performed by rolling a water-absorbing and swelling polymeric material so as to surround the structure. 2. In the underground construction method, which involves excavating the ground, applying foundation work, installing a structure on the foundation, and then backfilling,
A water-stop wrapping construction method for a structure buried in the ground, characterized in that the structure is surrounded by a soil material mixed with a water-absorbing and swelling polymer material and backfilled.