JPS6332021A - Light-weight banking work for land-slidable and soft ground - Google Patents

Abstract

PURPOSE:To prevent the subsidence of the ground by improving the drainage of void water by combining a draining means by which water-permeable granular drainage plates are buried through a banking material consisting primarily of expanded plastics such as expanded styrol, etc., to minimize the banking load, banking, and soft ground. CONSTITUTION:Water-permeable granule drainage plates 3 formed by solidifying spherical granules of expanded polystyrene 15, etc., by an adhesive 6 into a plate form are buried in the upper layer of soft ground to form a drainage means. Expanded plastic plates 21 consisting of expanded styrol plates 15, etc., are stacked up on the drain means. The granular drain plates are continuously interposed on the boundary between the expanded plastic plates laminate layer end and the side banking to form connected bankings. Surface covering soil 20 is formed on the uppermost position of the plastic plates 21 to construct a pavement structure consisting of the plastic plates 21, sand 22, roadbed soil 23, and the surface layer 24, having a great shearing compressive strength. Since spring water in soft ground including land-slidable portion can be drained, the land sliding and subsidence can thus be prevented.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a lightweight embankment construction method for landslide locations, soft ground locations, etc. that minimizes the embankment load and does not cause subsidence of the embankment even on soft ground. .

<Conventional technology> Conventionally, there are many methods for embankment on soft ground, such as the so-called sheet method and pile driving method, in which a sheet is laid on the soft layer and the upper surface is covered with soil using this bearing capacity1. Newly known is the development of vIT materials, that is, a lightweight embankment construction method in which foamed polystyrene blocks, which serve as lightweight members, are simply piled up.

<Problems to be Solved by the Invention> In this case, when embanking in areas with soft ground that is simply a flat surface, the embankment can be improved by selecting the laying area and fulcrum adjustment of the sheet, the laying width of the expanded polystyrene blocks, etc. The load is distributed and reduced to prevent subsidence. In addition, by excavating natural soil and adjusting the weight of the embankment and excavated soil, it is possible to prevent subsidence by balancing the embankment load. Under these conditions, simply applying conventional construction methods cannot handle pore water and spring water, and the landslide earth pressure on the slope reaches the embankment, making it impossible to obtain stable bearing capacity.

In view of the above-mentioned circumstances, the present invention is based on a foamed plastic board such as a foamed polystyrene board that minimizes the embankment load, and also provides an effective drainage means by appropriately interposing a granular drainage board made of solidified foamed polystyrene granules on the periphery. By combining,
To provide a light embankment construction method for landslide areas, soft ground areas, etc., which drains pore water and spring water even in soft ground including landslide areas, and does not cause subsidence as a whole.

Means for Solving the Problems> The present invention provides a water-permeable granular drainage board made of spherical granules made of expanded polystyrene etc. hardened into a raised shape with asphalt and adhesive on the upper surface of a predetermined soft ground. They are buried at intervals to serve as a drainage means, and foamed plastic plates made of foamed polystyrene plates or the like having a small unit volume mass and a prescribed size are stacked on top of these to a prescribed height, and the boundary between the laminated end face of the foamed plastic plates and the side embankment, etc. A granular drainage plate having the same structure as described above is continuously interposed to connect the embankment, and the uppermost position of the foamed plastic plate is covered with a surface layer of soil. In this case, the surface covering soil is sheared.

A thin pressure-resistant foamed plastic plate with high compressive force.

It consists of a pavement structure made of sand, roadbed soil, etc.9 surface layer, or a concrete bed.

A second invention is the first invention in which, when the foamed plastic plates are laminated, a supporting and reinforcing sheet is interposed at each level or appropriate level of the foamed plastic.

Due to the above-mentioned construction method, the embankment load on soft ground is drastically reduced because the embankment is mainly made of foamed plastic plates such as foamed polystyrene plates with small unit volume mass, and this embankment material is warm embankment and Since permeable granular drainage plates are arranged between soft ground, it allows for good drainage of pore water and spring water, and prevents subsidence. In particular, this means that even if there is an existing slope where one side is a landslide area, the landslide itself can be prevented because spring water can be collected, and the flow pressure will not be applied to the soft ground. In addition, since the surface soil covering is done by laying thin pressure-resistant foamed plastic plates, concrete slabs, etc., the overburden load is dispersed, and from this point of view, uneven settlement is not observed. Furthermore, even if the degree of softness is high, it can be sufficiently overcome by interposing a sheet as appropriate between the laminated foamed plastic plates.

<Example> The present invention will be described below based on the drawings of the example.

Figure 1 shows a case in which soft ground A is to be filled, and an existing slope area B, which is contiguous with this on one side and is prone to landslides, and the embankment on the other side is used as a retaining wall. First, this retaining wall 1
A concrete wall 1a is constructed with a predetermined embankment height β' at a position separated from the slope B by a predetermined embankment width λ. Next, granular drainage plates 3 are dropped and buried in narrow grooves 2 excavated at regular intervals on this slope B to form drainage walls 3'. In this case, the structure of the granule drainage plate 3 consists of four groups of spherical foamed granules with particle diameters of about 2 to 5 mm, which are foamed polystyrene beads heated and expanded 30 to 60 times to form closed cells, which have viscosity and water resistance. Asphalt 5 and polymer adhesive 6 are mixed together so as to be sprinkled and hardened into a so-called raised plate body. Water-permeable substrate 7
(For example, Styrodrain manufactured by Kitanihon Kagaku Kogyo Co., Ltd.), and the water-permeable substrate 7 is covered with a bag-shaped water-permeable fabric 8 made of synthetic lIi fiber plain weave fabric as required. The size of this granular drainage board 3 is about the same as that of a general construction board, for example, 3x6 (3
It has an area of 200 mm (shaku x 6 shaku) and a thickness of 200 mm. In addition, when vertically burying the granular drainage board 3, first, as shown in FIG. After a step of vertically driving the earth and sand Ba into the outer frame 9 to form a shape, and an excavation step of excavating the soil Ba in the outer frame 9 with a civil engineering machine such as an auger to form a narrow groove 2, granular drainage is carried out inside the outer frame 9. This can be done by a setting process of dropping the board 3 and a process of removing the bales of the outer frame 9, or when burying the U-shaped water collection pipe 10 in the lower surface of the granular drainage plate 3, after the excavation process, it can be done in the outer frame 9. , U-shaped water collection pipe 10 at the bottom end
Insert the core frame 11 to which the water collection pipe 10 is removably attached, and perform the pipe setting process in which the water collection pipe 10 is slightly depressed into the bottom of the narrow groove 2 (see Fig. 5C). Loosen the bolt shaft lever 12 that locks the bolt 10, and then loosen the hook 1 at its lower end.
3 away from the stop pin 14 (see FIG. 6), and through the core frame handling step of pulling up the bond core frame 11, the water collection pipe 10 is laid at the bottom. Next, if the granular drainage plate 3 is dropped into the outer frame 9 in the same manner as described above, the granular drainage plate 3
is placed on the water collection pipe 10. Finally, by pulling out the outer frame 9 and backfilling the surrounding gap, the granular drainage board 3 is vertically buried on the slope B. In reality, the narrow groove 2 is the granular drainage plate 3.
is the minimum gap into which the outer frame 9 can be dropped, so when the outer frame 9 is handled, it is naturally backfilled by the surrounding earth pressure.

Further, the narrow groove 2 can be formed by excavating a groove with the minimum gap as described above, and therefore the overall compaction state of the slope B portion does not change. In addition, in forming the narrow groove 2, sheet piles (not shown) may be simply driven into both sides at a predetermined interval, and the inside thereof may be excavated with an auger or the like.

After forming a drainage wall 3' on the slope B with detailed rows of granular drainage plates 3, lightweight embankment materials are stacked in the embankment space C up to the retaining wall 1. That is, the foamed plastic board 15 which becomes this lightweight embankment material is used as the foamed polystyrene board 15 having a small unit volume mass. The size of this Styrofoam board 15 is, for example, 3
It presents a board with an area of X6 (3 shaku x 6 shaku) and a thickness of 420 mm. In this case, first, backfill and @soil connection granular drainage plates 16 having the same configuration as described above are arranged inside the retaining wall 1, and the same configuration as described above is arranged on the upper surface of the soft ground A that will be the bottom of the embankment space C. Granular drainage plates 17 for flow channels are laid at predetermined intervals. However, the granular drainage plate 17 for the flow channel is sloped a to improve the flow of seepage water. In this state, the foamed polystyrene plates 15 are placed in a horizontal state and stacked one on top of the other so that the abutment positions are alternately vertical and horizontal. Furthermore, when laminating the foamed polystyrene plates 15, a granular drainage plate 18 for a waterway, which serves as a sailor's blow, is interposed between the laminated plates. Of course,
The base ends of these granular drainage plates 18 and 17 are backfilled with the tips of the granular drainage plates 3 on the slope B section, and @granular drainage plate 16 for soil connection is used.
It faces the end and is configured to drain water outward from a discharge channel 19 provided in one part of the retaining wall.

In this way, the surface layer covering soil 20 is applied to the upper surface of the stacked Styrofoam plates 15. This surface layer covering soil 20 is more compressible from the bottom in Figure 1.

Pressure-resistant foamed plastic plate 21 (e.g., Yukafoam manufactured by Mitsubishi Yuka Co., Ltd.), which has a large shearing force, sand 22, and roadbed ±
23 and a surface layer 24 on the top surface.

However, this pressure-resistant foamed plastic plate 21 has a compressive strength of 2.
5-4.0Kg/c12, shearing force 15-30! :l/
C12 pressure resistant type, for example, compressive strength 4.0Kg
If the value is greater than /cd, the strength will further increase, but it will be expensive and impractical, and if the value is less than 2.5KO/C112, the strength will be too weak to be adopted.

To explain this effect now, first of all, since the foamed polystyrene board 15, which is the main body of this embankment, has a small unit volume mass, the stress applied to the soft ground WA is minimal, so no settlement is observed.

In addition, the saturated pore water that accumulates in this soft ground A is removed from the granular drainage plate 17 for the flow channel located at the boundary with the Styrofoam plate 15.
The granular particles permeate into the interior, and due to the water permeability of the granular drainage plate 17 itself, they flow down one after another and are drained out of the retaining wall 1 through the discharge channel 19.

The granular drainage plates 3.16 and 17.18 here have an internal structure of approximately 30% hole welding made by hardening spherical foamed granules 4 with a particle size of 2 to 5 mm, so the interior of the drainage plates is a type of May constitute a waterway. However, the outer periphery is covered with a water-permeable fabric 8 which acts as a filter and prevents the inflow of earth and sand.

In addition, in the slope A part where landslides are likely to occur, drainage walls 3' made of granular drainage plates 3 are buried at regular intervals, so that spring water, which is one of the causes of landslides, can be collected. The drainage wall 3' itself presents a kind of waterway, and the water flows down one after another, using the waterway granular drainage plate 17 at the boundary with the soft ground A as a drainage channel, and is guided to the outside of the retaining wall 1, and flows onto the slope B. The embankment material that is in direct contact with the material is also a lightweight embankment material made of styrofoam board 15.
There is no load that would cause the slope to slide, and all of these do not cause landslides on the 8 parts of the slope.

Furthermore, this means that the structure of the surface layer covering soil 20 can be changed from sand 22. The pavement structure of the roadbed ± 231 and the surface layer 24 disperses the overloading load and applies a vertical load to the foamed polystyrene plates 15, and together with this, the retaining wall 1 is constructed without inviting external forces such as lateral flow pressure.
Also serves as protection.

FIG. 7 shows another embodiment in which the surface layer covering soil is a concrete bed plate, and this is an example in which the surface layer covering soil 20 does not want to be too thick and aims to be lighter.

In this embodiment, the structure of the retaining wall 1 is H steel 1b.
and a sheet pile 1C is arranged in between, and in the embankment space C, the granular drainage board 17 for the flow channel, the Styrofoam board 15, the granular drainage board 18 for the flow channel, and the Styrofoam board 15 are sequentially laminated from below as described above. A concrete floor 25 of a predetermined shape is placed on top of this to cover it with soil. Further, in this embodiment, a U-shaped water collection pipe 10 is provided at the lower end of the granular drainage plate 3 on the slope B, and the U-shaped water collection pipe 10 is connected to the water collection pipe 10.
' is disposed at a predetermined position on the granular drainage plate 17 for the flow channel, and its tip is guided outside the retaining wall 1 so that water can be drained directly into the side gutter 26.

Here and there, the surface covering soil 20 of the concrete floor plate 25 and the lightweight embankment material of the Styrofoam board 15 are light and do not increase stress in the soft ground A, so they do not cause subsidence. Of course, slope B
There are no landslides on the site itself.

FIG. 8 shows another embodiment in which a road embankment having a predetermined height is constructed on soft ground. This consists of Styrofoam plates 15 of a predetermined size, with granular drainage plates 17 similar to those previously described buried at appropriate intervals on the upper surface of a predetermined soft ground A to be filled.
The groups are stacked one after another so that the overlapping joints are alternately located to form a stack of a predetermined height, and the granule drainage plate 16 having the above structure is continuously disposed on the stepped stacked end surface 15a, A side embankment 27 made of ordinary earth and sand is provided on the outside of the granular drainage board 16, and the uppermost foamed polystyrene board 15 is
A pressure-resistant foamed plastic board 21, sand 22, roadbed 23, and a surface layer 24 such as asphalt are provided on top to form a road embankment. Of course, even in this case, a drainage channel made of the granular drainage plate 17 is provided at one end of the granular drainage plate 16 facing the side gutter 26 outside the side embankment 27.

Even in this road embankment, since the main part of the embankment load is the foamed plastic plate that becomes the styrofoam plate 15, the embankment load is drastically reduced and does not cause settlement, and the styrofoam plate 1
Since a drainage means serving as a granular drainage plate 16 is also interposed between 5 and the side embankment 27, the embankment connection is reliable and cracks do not occur.

FIG. 9 shows another embodiment in which road embankment is carried out on soft ground with a high degree of softness. During the embankment process, when laying the Styrofoam plates 15, mesh type, flat yarn type,
Water permeable sheet 2 made of polypropylene plain weave type etc.
8 was installed to provide support and reinforcement.

That is, by laying the sheet 28, which serves as support and reinforcement when stacking the polystyrene foam plates 15, over the entire area (the entire surface) of each tier or appropriate tier, the supporting capacity is improved and the embankment can be used in areas with high softness. It can adequately cope with the situation and does not show any subsidence.

<Effects of the Invention> As mentioned above, the lightweight embankment construction method for landslide areas, soft ground areas, etc. of the present invention is based on the embankment material mainly consisting of small foamed plastic plates with a unit volume mass, laminated to an appropriate height, and the foamed plastic The embankment load on the soft ground surface is minimized by connecting the embankment to the end faces and bottom of the laminated plates, interposing granular drainage plates for flow channels, and applying a surface layer of soil to the topmost foamed plastic board. In addition, since pore water, spring water, etc. can be drained, subsidence is not caused.

In particular, even if one side of the slope is prone to landslides, a granular drainage plate is buried to collect spring water and collect 1q of water, preventing landslides and, in turn, preventing flow pressure from being applied to the soft ground side, ensuring embankment balance. It doesn't break down. In addition, the connection of the side embankment is good, there are no cracks between the lightweight embankment members, and the top layer of surface covering soil is constructed using a pavement structure based on thin pressure-resistant foamed plastic plates, or an arrangement of concrete slabs. Therefore, a uniform load is applied to the laminated foamed plastic plates, and there is no risk of local subsidence.

Furthermore, in the case of soft ground with a high degree of softness, by appropriately interposing a supporting and reinforcing sheet between the laminated foamed plastic plates, it is possible to increase the supporting force and sufficiently cope with the problem.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a longitudinal cross-sectional side view of the main part when using a retaining wall, Fig. 2 is a front view showing the buried state of the granular drainage board on the slope, and Fig. 3 is a granular drainage plate. Figure 4 is a partially cutaway slope view of the body drainage board, Figure 4 is a slope view of the water collection pipe, Figure 5 A, B, C, and D are explanatory diagrams showing the order of embedding the granule drainage board on the slope, and Figure 6 is A slope view of the core frame body, Fig. 7 is a longitudinal sectional view of the main part showing another embodiment, Fig. 8 is a longitudinal sectional view of the main part using the same road embankment, and Fig. 9 is a longitudinal sectional view of the main part using the same sheet. It is. 1... Retaining wall, 3... Granular drainage board, 4... Foamed granules, 5... Asphalt, 6... Adhesive, 7... Water-permeable substrate, 8... Water-permeable fabric , 15... Styrofoam board, 16... Granular drainage board for backfilling and embankment connection, 17.
18... Granular drainage board for flow channel, 28... Sheet.

Claims (1)

[Scope of Claims] 1. Water-permeable granular drainage boards made of spherical granules made of foamed polystyrene, etc., hardened with asphalt and adhesive are buried at appropriate intervals on the upper surface of a predetermined soft ground and foamed. The plastic plates are stacked to a predetermined height, and a granular drainage plate having the above structure is continuously interposed between the laminated end face of the foamed plastic plates and the side embankment to connect the embankment, and at the top of the foamed plastic plates. A lightweight embankment construction method for landslide areas, soft ground areas, etc., characterized by applying a surface layer of soil. 2. The surface layer covering soil has a compressive strength of 2.5 to 4.0 Kg/cm^
2. A lightweight embankment construction method for landslide locations, soft ground locations, etc., as claimed in claim 1, which is a pavement structure consisting of pressure-resistant foamed plastic plates with a shearing force of 15 to 30 kg/cm^2, sand, roadbed soil, and surface layer. 3. The lightweight embankment construction method for landslide locations, soft ground locations, etc., as set forth in claim 1, wherein the surface covering soil is concrete and floor slabs. 4. The lightweight embankment construction method for landslide locations, soft ground locations, etc. as claimed in claim 1, wherein the side embankment is a retaining wall. 5. Water-permeable granular drainage boards made of spherical granules made of foamed polystyrene etc. hardened with asphalt and adhesive are buried at appropriate intervals on the upper surface of a specified soft ground, and foamed plastic boards are stacked on top of these. are laminated to a predetermined height while intervening supporting and reinforcing sheets in appropriate stages,
A landslide characterized in that a granular drainage plate having the above structure is continuously interposed at the interface between the laminated end face of the foamed plastic plate and the side embankment to connect the embankment, and a surface layer of soil is applied to the uppermost position of the foamed plastic plate. Lightweight embankment construction method for areas with soft ground.