JP3609004B2 - Low friction member and method for reducing shear earth pressure of structure using the low friction member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a low friction member and a method for reducing the shear earth pressure of a structure using the low friction member, and more particularly, a common groove under a road, a subsurface open tunnel, a power plant intake channel, a water discharge channel, and the like. The present invention relates to a low-friction member suitable for underground structures, underground parts of buildings, and the like, and a method for reducing the shear earth pressure of a structure using the low-friction member.
[0002]
[Prior art]
For example, an open-cut tunnel is usually built in a hole dug in the ground. FIG. 16 shows a conventional example of a rectangular underground structure 1 constructed in a hole H dug in the ground. In FIG. 16, the upper slab 1a of the underground structure 1 is covered with soil and sand 2 for leaving the underground structure 1 in an embedded state without any gaps.
[0003]
Since these soils and sands 2 are placed on the upper slab 1a of the underground structure 1, they are hereinafter referred to as "upper soil 2" and holes corresponding to the outer wall surfaces other than the upper slab 1a of the underground structure 1. The soil and sand of H will be referred to as “peripheral buried soil 3” for convenience. In addition, the code | symbol 1b in FIG.16 and FIG.17 is the space part in underground structure 1, Comprising: A car, a train, etc. can pass through this.
[0004]
Since the underground structure 1 is rectangular, the upper slab 1a has a planar shape. When the underground structure 1 having such an upper slab 1a having a planar shape is built in the hole H and then embedded with the upper soil 2, the upper soil 2 is received by the upper slab 1a.
[0005]
And since the underground structure 1 is normally embed | buried deep underground, the weight of the overburden 2 applied to the upper slab 1a becomes quite heavy. For this reason, the underground structure 1 is pressed downward by the upper soil 2 through the upper slab 1a. That is, the overburden 2 directly acts on the upper slab 1a of the underground structure 1 with its weight as earth pressure.
[0006]
When the ground including the underground structure 1 rolls as indicated by an arrow 4 in FIG. 17 due to, for example, an earthquake, the overlay soil 2 is displaced relative to the underground structure 1. When such misalignment occurs, the weight of the overlaid soil 2 acts not only on the upper slab 1a as a simple earth pressure but also as a shear earth pressure (force that pulls the upper slab 1a in the horizontal direction in the direction of arrow 4). Resulting in. For this reason, a large frictional force is generated between the upper loading soil 2 and the upper slab 1a. This frictional force may cause a large shear deformation in the underground structure 1.
[0007]
Further, the shear earth pressure is applied to the side surface of the underground structure 1 when the ground on the side of the underground structure 1 sinks in addition to when the upper soil 2 moves in the horizontal direction during the earthquake as described above. Occurs.
[0008]
Therefore, conventionally, the strength of the underground structure 1 is increased by increasing the number of reinforcing bars used in the underground structure 1 or increasing the amount of concrete used. Has been prevented from being damaged.
[0009]
[Problems to be solved by the invention]
However, the conventional underground structure 1 has a problem that the cost increases because it is necessary to increase the strength by increasing the number of reinforcing bars and the amount of concrete used as described above.
[0010]
Such a problem is not limited to the open tunnel of a subway, but also occurs in underground structures such as a common ditch under the road, an intake channel of a power plant, a discharge channel, and the like. .
[0011]
An object of the present invention is to solve such a conventional problem, and it is possible to prevent a large shear earth pressure from being generated in a structure buried in the ground due to an earthquake or ground subsidence. Accordingly, it is an object of the present invention to provide a low-friction member that does not require an increase in the strength of the structure and can suppress an increase in cost compared to the conventional one, and a method for reducing the shear pressure of the structure using the low-friction member.
[0012]
[Means for Solving the Problems]
The present invention is a low friction member and a method for reducing the shear earth pressure of a structure using the same, and is configured as follows in order to solve the above technical problem. That is, in the present invention, in order to reduce the friction between two relatively movable objects, in the low friction member disposed between the two objects, the two hard resin sheets or plates and the two hard materials are disposed. And a fluororesin sheet or plate disposed between the resin sheets or plates.
[0013]
In order to reduce friction between two relatively movable objects, the present invention provides a flexible bag having a certain level of strength and a certain volume in a low friction member disposed between the two objects, and the bag. And a fluid or soft material enclosed in the container.
[0014]
The method of reducing the shear earth pressure of a building using the low friction member according to the present invention includes disposing the above-described low friction member between the structure and the surrounding ground so that the structure is moved when the ground is relatively moved. A shear earth pressure acting on the structure is reduced by friction between an object and the ground.
[0015]
Next, each component will be described.
(Hard resin sheet or plate)
The size is determined according to the opposing surfaces of the two objects, and the thickness can be appropriately selected according to the use conditions. Since the hard resin sheet and the fluororesin sheet can be wound in a laminated state, long low-friction members can be gathered in a compact manner, so that handling becomes easy.
(Fluororesin sheet or plate)
Since the fluororesin has a very small friction coefficient, the friction coefficient between the two hard resin sheets or plates can be very small by sandwiching the fluororesin between the two hard resin sheets or plates. The fluororesin sheet or plate is sized according to the hard resin sheet or plate, and the thickness can be selected as appropriate. The fluororesin sheet or plate may be fixed to one of the two hard resin sheets or plates, or may not be fixed.
(bag)
For example, a flexible and waterproof bag is formed using a polymer material such as polyethylene or vinyl. By enclosing the fluid or soft material in this flexible bag, even if a large load is applied, the fluid or soft material can be maintained in a certain thickness without being crushed. Can do.
(Fluid)
As the fluid, water, air, various gases or liquids can be used.
(Soft material)
As the soft material, for example, a soft ground can be used. In this case, since the flexibility is lost when the moisture is removed, the bag is completely sealed to prevent the moisture from being removed. In addition, soil, polymer material, bentonite, etc. can be used alone or in combination.
(Structure)
It can be applied to underground structures and underground parts of multi-story buildings.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a low friction member and a method for reducing the shear pressure of a structure using the low friction member according to the present invention will be described below in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram for explaining a case where the low friction member of the present invention and the method for reducing the shear earth pressure of a building using the low friction member are applied to an underground structure 1. The underground structure 1 has a substantially rectangular cross section, and rectangular hollow portions 1b and 1b are formed inside the underground structure 1 for passing a subway, for example. The upper surface of the upper slab 1a of the underground structure 1 is flat, and the overlay soil 2 such as soil and sand is backfilled thereon. A low friction member 5 is disposed between the upper slab 1 a of the underground structure 1 and the upper soil 2. In addition, the code | symbol H in FIG. 1 is a hole, 3 is surrounding buried soil.
[0017]
As shown in FIG. 2A, the low friction member 5 includes two hard resin sheets 51 and 53 such as vinyl chloride and, for example, Teflon (trademark) disposed between the hard resin sheets 51 and 53. Name) and the like. As shown in FIG. 2B, the fluororesin sheet 52 is fixed to a hard resin sheet 53 disposed on the lower side, here, on the upper slab 1a side. Since the fluororesin sheet 52 has a very small coefficient of friction, the coefficient of friction when the hard resin sheets 51 and 53 on both sides thereof move relatively is very small.
[0018]
Note that the fluororesin sheet 52 may be fixed to the upper hard resin sheet 51 as shown in FIG. 3 (A), or may not be fixed to either as shown in FIG. 3 (B). Also good. Further, the low friction member 5 can be wound in a state where the two hard resin sheets 51 and 53 and the fluororesin sheet 52 are laminated and unwound at the time of use. Thereby, since the long low friction member 5 can be put together compactly, handling becomes easy. Further, the hard resin sheets 51 and 53 and the fluororesin sheet 52 can be formed into a plate shape by increasing the thickness.
[0019]
Next, the effect | action of this shear earth pressure reduction method is demonstrated. Now, as shown in FIG. 4, for example, when a lateral load in the direction of the arrow 4 is applied to the upper soil 2 due to vibration such as an earthquake, the upper soil 2 moves laterally and a positional shift occurs between the underground soil structure 1 and the upper soil 2. Arise.
[0020]
At this time, since the low friction member 5 is disposed between the underground structure 1 and the overburden 2, the hard resin sheet 51 on the upper soil 2 side of the low friction member 5 is placed on the fluororesin sheet 52. And move relative to the top soil 2. Thereby, the frictional force between the underground structure 1 and the overlying soil 2 becomes very small. Therefore, the shear earth pressure (force that pulls the upper slab 1a in the direction of the arrow 4) F acting on the underground structure 1 from the overlaid soil 2 becomes very small.
[0021]
Therefore, without increasing the strength of the underground structure main body 1 as much as before, that is, without increasing the amount of reinforcing bars and concrete used for the underground structure main body 1 as much as before, the underground structure main body It is possible to prevent damage during an earthquake.
[0022]
In addition, as shown in FIG. 5, the both ends of the low friction member 5 can be made to protrude outside the underground structure 1, and can be arrange | positioned. In this case, since the end portion 5a of the low friction member 5 is separated from the underground structure 1, the ground stress generated at the end portion 5a of the low friction member 5 is dispersed in the surrounding buried soil 3, and the underground structure 1 can be prevented.
[0023]
Further, as shown in FIG. 6, soft materials 6 such as rubber that are softer than the surrounding buried soil 3 can be disposed on both sides of the underground structure 1. Thereby, since the direct soil pressure Q which acts on the underground structure 1 from the surrounding buried soil 3 can be absorbed by the soft material 6, it is not necessary to make the strength of the underground structure 1 higher than necessary.
[0024]
Furthermore, as shown in FIG. 7, the soft material 6 can be arranged on both sides of the overlaid soil 2. In this case, by appropriately setting the thickness of the soft material 6, the displacement of the overlay soil 2 can be absorbed by the soft material 6. As a result, the ground stress transmitted from the overburden soil 2 to the surrounding buried soil 3 becomes extremely small, and an increase in the direct soil pressure Q acting on the side surface of the underground structure 1 from the surrounding buried soil 3 can be suppressed.
(Second Embodiment)
In the second embodiment, as shown in FIG. 8, the present invention is applied to a multi-story building 10 having an underground portion 11. The underground portion 11 is buried in the surrounding buried soil 3. And the low friction member 5 similar to the above is arrange | positioned between the surrounding buried soil 3 over the perimeter of the underground part 11.
[0025]
In this case, as shown in FIG. 9, when the surrounding buried soil 3 around the multi-story building 10 is displaced relatively downward due to ground subsidence, the multi-story building is constructed by the low friction member 5. The frictional force between the underground portion 11 of the object 10 and the surrounding buried soil 3, that is, the shear earth pressure F acting on the underground portion 11 from the surrounding buried soil 3 becomes very small. Therefore, even if the strength of the underground part 11 and the foundation part of the multi-story building 10 is not so high, it can be prevented from being damaged, so that the cost can be reduced.
(Third embodiment)
FIG. 10 shows a third embodiment of the present invention. This third embodiment is the same as FIG. 1 except that a large number of massive low friction members 12 are arranged instead of the low friction member 5 of FIG.
[0026]
As shown in FIG. 11, the low friction member 12 includes a bag 13 in which a fluid or soft material 14 is enclosed. The bag 13 has a certain level of strength, a certain volume, and waterproofness, and is formed of a polymer material such as polyethylene or vinyl flexibly.
[0027]
As the fluid, various liquids such as water or various gases such as air can be used. The soft material 14 may be any material that can be freely deformed when a predetermined load is applied. For example, soft ground, soil, polymer material, bentonite and the like can be used alone or in combination. .
[0028]
By filling the fluid 13 or the soft material 14 in the bag 13 having a certain volume, it is possible to prevent the bag 13 from being crushed even when a certain load or more is applied to the bag 13. The flexibility as the friction member 12 can be maintained.
[0029]
In the present embodiment, soft ground is used as the soft material. However, there is a possibility that the rigidity of soft ground may increase due to consolidation (a phenomenon in which water or air in the soil gap is expelled by pressure and the density increases). Therefore, here, the bag 13 is completely sealed to prevent the water and air in the soft ground from escaping. A number of the low friction members 12 are arranged on the slab 1a of the underground structure 1 with almost no gap.
[0030]
Now, as shown in FIG. 12, when a lateral load in the direction of the arrow 4 is applied to the overlying soil 2 due to an earthquake or the like, the underground structure 1 is displaced. At this time, since the low friction member 12 is deformed, the frictional force between the underground structure 1 and the overburden 2 becomes very small. Therefore, the shear earth pressure F acting on the underground structure 1 is also very small. Therefore, it is not necessary to increase the strength of the underground structure 1 more than necessary, and the cost can be reduced.
[0031]
The low-friction member 12 described above can be disposed around the underground portion 11 of the multi-story building 10 as shown in FIG. In this case, as shown in FIG. 14, when the surrounding buried soil 3 is relatively moved downward due to ground subsidence, the low friction member 12 is deformed. Therefore, the underground portion 11 and the surrounding buried soil of the multi-story building 10 are deformed. Since the frictional force with 3 is very small, the shear earth pressure acting on the underground portion 11 is very small.
[0032]
The low friction member 12 can be arranged in multiple stages as shown in FIG. In this case, the entire deformation amount of the low friction member 12 is increased.
In the above-described embodiment, the case where the present invention is applied to the underground structure 11 or the underground portion 11 of the multi-story building 10 has been described. However, the present invention is not limited to the common groove under the road, the underground tunnel, the power generation It can also be applied to the intake and discharge channels.
[0033]
【The invention's effect】
As described above, according to the present invention, since the shear earth pressure acting on the underground structure or the underground part of the structure at the time of an earthquake or subsidence can be reduced, the underground part of the underground structure or the structure can be reduced. Since it is not necessary to increase the strength as in the conventional case, the number of reinforcing bars and the amount of concrete used can be reduced as compared with the conventional case, thereby reducing the cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of the present invention.
FIG. 2 is a view showing a low friction member according to the first embodiment of the present invention.
FIG. 3 is a view showing a low friction member according to the first embodiment of the present invention.
FIG. 4 is a diagram for explaining the operation of the first exemplary embodiment of the present invention.
FIG. 5 is a diagram showing another example of the first embodiment of the present invention.
FIG. 6 is a diagram showing another example of the first embodiment of the present invention.
FIG. 7 is a diagram showing another example of the first embodiment of the present invention.
FIG. 8 is a diagram showing a second embodiment of the present invention.
FIG. 9 is a diagram for explaining the operation of the second exemplary embodiment of the present invention.
FIG. 10 is a diagram showing a third embodiment of the present invention.
FIG. 11 is a view showing a low friction member according to a third embodiment of the present invention.
FIG. 12 is a diagram for explaining the operation of the third exemplary embodiment of the present invention.
FIG. 13 is a diagram showing a fourth embodiment of the present invention.
FIG. 14 is a diagram for explaining the operation of the fourth exemplary embodiment of the present invention.
FIG. 15 is a diagram showing another example of the fourth embodiment of the present invention.
FIG. 16 is a view showing a conventional underground structure.
FIG. 17 is a diagram for explaining shear earth pressure acting on a conventional underground structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Underground structure 2 Overlay soil 5,12 Low friction member 11 Underground part 13 of a building 13 Bag 14 Soft material 51,53 Hard resin sheet 52 Fluororesin sheet

Claims (8)

In order to reduce the friction between the underground part of the structure at least partially embedded in the ground and the surrounding ground, between the underground part of the structure and the surrounding ground In the low friction member to be arranged,
Two hard resin sheets or plates;
A low-friction member comprising: a fluororesin sheet or plate disposed between the two hard resin sheets or plates. The low-friction member according to claim 1, wherein the fluororesin sheet or plate is fixed to one of the two hard resin sheets or plates. The low friction member according to claim 1 or 2, wherein the two hard resin sheets and the fluororesin sheet are wound. In order to reduce the friction between the underground part of the structure at least partially embedded in the ground and the surrounding ground, between the underground part of the structure and the surrounding ground In the low friction member to be arranged,
Into a closed and and fully sealed flexible bag above a certain intensity and a certain volume, fluids or soft material is formed on the encapsulated mass,
A low-friction member characterized in that a large number of low-friction members are arranged side by side along the structure between an underground part of the structure and the surrounding ground . The low friction member according to claim 4, wherein the soft material is soft ground. At least a part of the structure is embedded in the ground, and the low-friction member according to any one of claims 1 to 5 is disposed between the ground part of the structure and the surrounding ground. A low friction member characterized in that when the ground moves relative to the structure, friction between the structure and the ground is reduced, and shear earth pressure acting on the structure is reduced. A method for reducing the shear pressure of the structure used. The structure is an underground structure completely embedded in the ground, and the low friction member is disposed on at least the upper surface of the underground structure, and the upper soil is backfilled on the low friction member. The friction between the underground structure and the overlay soil is reduced when the overlay soil is relatively moved during an earthquake, and the shear earth pressure acting on the underground structure is reduced. A method for reducing the shear earth pressure of a structure using the low friction member according to claim 6. The structure is an underground part of a building, and the friction between the underground part and the ground is reduced when the ground sinks by disposing the low friction member between a side surface of the underground part and the ground. The shear earth pressure reducing method for a structure using a low friction member according to claim 6, wherein the shear earth pressure acting on the underground portion is reduced.

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