JP2013060797A - Device for preventing flotation of manhole due to liquefaction phenomenon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems where a manhole buried in a road or around a building is moved upward and protruded above a surface of a ground (a street or a roadway) due to fluidization of the ground generated by a large earthquake and thereby causing a major hazard to moving traffic or the like and, at the same time, inflicting enormous damage as a result of disturbance and loss of original functions such as drainage and the like when several kinds of pipes connected in the manhole under the ground for water supply, sewerage, electricity supply and communication are broken or moved upward by huge pressure.SOLUTION: When a liquefaction phenomenon of the ground is generated by an earthquake, a device for preventing flotation of a manhole 1 due to the liquefaction phenomenon prevents the manhole 1 from the floatation by reducing pressure to float the manhole 1 in a manner that: introduces water content of liquefied or fluidized soil around a bottom plate 9 and surroundings of a box body 3 of a manhole 1 into both a main drainage pipe 8 and a sub-drainage pipe 11 through many small holes 7 provided therewith; and drains the water content into the box body 3 through the main drainage pipe 8, a drain pipe 15 and the sub-drainage pipe 11.

Description

Open to the ground (GL) surface around roads, buildings, etc., and embed a box made of, for example, cylindrical concrete in the ground, and pipes for water, sewerage, electricity, communication, etc. around the box Any manhole (manhole = manhole, a hole in which a person can work inside) with a lid made of heavy cast iron, concrete, etc. is widely used at the opening on the ground surface. The present invention relates to an apparatus for preventing a manhole from rising due to a liquefaction phenomenon, which comprises a main drainage pipe, a secondary drainage pipe, and a drainage pipe in a new and existing manhole.

Recently, large earthquakes that occur frequently, especially the fluidization phenomenon of the ground caused by the recent great earthquake disaster, has become a very serious social problem.
In the fluidization phenomenon, the ground containing sand and moisture is liquefied and fluidized due to the vibrations repeated by the earthquake, breaking the ground, roads, etc. in a very wide area, raising or sinking the road and its pavements and buildings. Damage to the foundation part, etc., such as destruction, levitation, depression, subsidence,
In addition, manholes buried around roads and buildings due to the rising pressure of fluid sediment rise up to the surface (on roads, roadways, etc.) and project, causing traffic and other major obstacles. Various pipes for water supply, sewerage, electricity, communication, etc. that are connected to the pipe break or rise due to strong pressure, and the original drainage function and other functions are hindered, resulting in loss of great damage. ing.

Utility model registration No. 2602652 Utility model registration No. 2592718

Manholes buried around roads, buildings, etc. due to the rising pressure of fluidized sediment due to fluidization phenomenon rise to the surface (roads, roadways, etc.) and project, causing traffic and other major obstacles. The problem that various pipes for water, sewerage, electricity, communication, etc. that are piped in the ground are raised and broken by strong pressure, impairing and losing the original drainage function and other functions. It is an object of the present invention to solve the manhole floating prevention device due to the liquefaction phenomenon according to the invention.

The invention of claim 1 opens on the ground surface around roads, buildings, etc., embeds a box made of cylindrical concrete, and connects various pipes to the peripheral surface of the box. In a manhole equipped with a lid made of cast iron or the like at the opening on the surface, a main drainage pipe with a plurality of small holes for water passage on the peripheral surface is passed through the bottom plate from the box, and the ground below the bottom plate A secondary drainage pipe with a plurality of small holes for water passage on the peripheral surface is provided in the vertical direction along the outer periphery of the box, and its tip is placed on the ground around the box. It penetrates the peripheral wall of the box higher than the groundwater level and opens into the box, and the lower end is buried at the set depth of the ground below the bottom, and the drainage pipe is provided vertically along the inner wall of the box. The upper end is connected near the opening at the tip, and the lower end is connected near the upper end of the main drain pipe,
When fluidization occurs due to an increase in the groundwater level due to an earthquake, etc., or due to an increase in the water pressure at the bottom of the box 3 and the surrounding water, the water from the bottom of the box and the surrounding liquefied soil is used as the main drain pipe and the sub drain pipe. Introduced into both pipes through a large number of small holes, draining the introduced water into the box through the main drain pipe, drain pipe, and sub drain pipe, reducing the pressure to rise the manhole to the ground surface, The problem is solved by an apparatus for preventing the manhole from rising due to the liquefaction phenomenon, which is provided to prevent the manhole from rising due to the liquefaction phenomenon.

According to a second aspect of the present invention, there is provided the manhole floating prevention device according to the first aspect of the present invention, wherein the manhole is new, existing, and does not limit the size, shape, material, etc. It solves the problem.

The invention of claim 3 is provided with at least one main drain pipe, sub drain pipe and drain pipe, and the main drain pipe and the sub drain pipe are provided on the circumferential surface of a set length steel pipe or PVC pipe. What solved the problem by the manhole floating prevention device by the liquefaction phenomenon according to claim 1, characterized in that it has a large number of small holes for water passage, and the drain pipe is a steel pipe or a vinyl chloride pipe. It is.

The invention according to claim 4 is provided with a main drain pipe and a drain pipe as a single pipe, and a plurality of small holes for water flow are provided on the peripheral surface of the pipe corresponding to the main drain pipe. The problem is solved by the apparatus for preventing a manhole from floating due to the liquefaction phenomenon according to claim 1.

According to the invention of claim 5, when the main drain pipe and the sub drain pipe are embedded below the bottom plate 9 of the box 3 or around the box 3, the periphery of each pipe is water-permeable such as crushed stones and pebbles. The object is solved by the apparatus for preventing the manhole from floating due to the liquefaction phenomenon according to claim 1, characterized in that the object is surrounded by a material 19.

(1) The liquefaction phenomenon that the ground is liquefied and fluidized due to repeated vibrations caused by earthquakes, etc., and the manhole bulges above the ground surface due to the liquefied and fluidized soil uplift pressure (water pressure). In the present invention, the lower part of the bottom of the manhole box and the surrounding ground are liquefied, the moisture in the fluidized soil is removed from the main drain pipe (ground below the bottom board) Introduced into both pipes through many small holes in the pipe (surrounding ground) and drained the introduced water into the box through the main drain pipe, drain pipe, and sub drain pipe. And the surrounding liquefaction, fluidized soil can be drained, soil liquefaction, fluidization can be prevented, and as a result, the uplift pressure to rise the manhole to the ground surface side can be reduced. Prevent manholes from rising due to liquefaction There is an excellent effect that can Rukoto.
(2) To drain water introduced into the main drainage pipe, drainage pipe, sub drainage pipe, etc. through many small holes into the box at a position higher than the groundwater level around the manhole in the box. As a result, the drainage action is not performed at normal times when the liquefaction phenomenon has not occurred. Therefore, the original function of the manhole is not hindered and the drainage action is performed in an overflow manner only when the liquefaction phenomenon occurs. There is an effect that can prevent the rise of.
(3) The device according to the present invention has excellent versatility that can be provided at low cost by simple construction in any manhole that is not limited to new, existing, large, small, shape, or material.
(4) When embedding the main drain pipe and sub drain pipe of the apparatus of the present invention in the bottom of the box and the surrounding ground, the surroundings of both pipes are previously surrounded by a water-permeable material such as crushed stone and pebbles. By providing, it is possible to prevent clogging of the small holes in both pipes and maintain the moisture extraction effect of the liquefied and fluidized soil for a long period of time.
(5) By providing a plurality of main drain pipes and sub drain pipes, the above-described effects and features can be promoted.

These are the longitudinal cross-sectional views which show the structure outline of the Example of this invention. Example 1

A main drainage pipe with a plurality of small holes for water passage on the peripheral surface passes through the bottom plate from the box and is buried at the set depth of the ground below the bottom plate, while the auxiliary drain pipe is boxed. In the vertical direction along the outer circumference of the box, its tip penetrates the box peripheral wall at a position higher than the groundwater level of the ground around the box and opens into the box, and the lower end is the set depth of the ground below the bottom board. Liquefaction phenomenon with drainage pipes installed in the vertical direction along the inner wall of the box, with the upper end connected near the opening at the tip, and the lower end connected near the upper end of the main drain pipe A manhole levitation prevention device.

FIG. 1 is a diagram showing a schematic configuration of an embodiment of the present invention.

Reference numeral 1 is a manhole, 2 is the ground surface (GL), 3 is a box, 4 is various pipes, 5 is an opening, 6 is a lid, 7 is a small hole, 8 is a main drain pipe, 9 is a bottom plate, 10 is Ground, 11 is a secondary drain pipe, 12 is a tip (sub drain pipe), 13 is a groundwater level, 14 is a lower end (sub drain pipe), 15 is a drain pipe, 16 is an upper end (drain pipe), and 17 is a lower end. (Drainage pipe), 18 is an upper end (main drain pipe), 19 is a water-permeable material such as crushed stone and pebbles.

The present invention opens on two ground surfaces (GL) such as roads and buildings, and embeds a box 3 made of cylindrical concrete in the ground. In a manhole 1 which is connected to a pipe 4 for communication or the like and has a lid 6 made of cast iron or the like in the opening 5 of the ground surface 2

While embedding a main drain pipe 8 having a plurality of small water-passing holes 7 in the peripheral surface, penetrating the bottom board 9 from the inside of the box 3 to a set depth of the ground 10 below the bottom board 9,

A sub-drain pipe 11 having a plurality of small water-passing holes 7 on the peripheral surface is provided in the vertical direction along the outer periphery of the box 3, and its tip 12 is the groundwater level 13 of the ground 10 around the box 3. The lower end 14 is embedded in the set depth of the ground 10 below the bottom plate 9 while penetrating through the higher wall of the box 3 and opening in the box 3,

15 is provided in the vertical direction along the inner wall of the box 3, and its upper end 16 is connected to the vicinity of the opening of the tip 12, and the lower end 17 is connected to the vicinity of the upper end 18 of the main drain pipe 8,

When fluidization occurs due to an increase in the groundwater level 13 due to an earthquake, a rise in the bottom plate 9 of the box 3 and the surrounding water pressure, etc., the water in the bottom plate 9 of the box 3 and the surrounding liquefied soil is removed from the main drainage pipe. 8. It introduce | transduces in both pipes through many small holes 7 of the sub drainage pipe 11, This water is drained in the box 3 through the main drain pipe 8, the drain pipe 15, and the sub drain pipe 11, and a manhole An apparatus for preventing a manhole from rising due to a liquefaction phenomenon is provided to reduce the pressure of levitating 1 to the ground surface and thereby prevent the manhole from rising due to a liquefaction phenomenon.

The manhole 1 is not newly limited, existing, or limited in size, shape, material, or the like.

At least one main drain pipe 8, sub drain pipe 11, and drain pipe 15 are provided (one in each of the illustrated examples). The main drain pipe 8 and the sub drain pipe 11 are steel pipes of a set length or A plurality of small holes 7 for water passage are provided on the peripheral surface of the PVC pipe, and the drain pipe 15 is a steel pipe or a PVC pipe.

Although not shown, the main drain pipe 8 and the drain pipe 15 are provided as a single continuous pipe, and a plurality of small holes for water passage are formed on the peripheral surface of the pipe corresponding to the main drain pipe 8. It is also possible to prepare 7 after dawn.

When the main drain pipe 8 and the sub drain pipe 11 are embedded below the bottom plate 9 of the box 3 or around the box 3, the circumference of each pipe is surrounded by a water-permeable material 19 such as crushed stone and pebbles. Prepare.

The apparatus according to the present invention has features that can be implemented universally in any manhole that is new, existing, and does not limit the size, shape, material, and the like.

1 Manhole 2 Ground (GL)
3 Box 4 Various pipes 5 Opening 6 Lid 7 Small hole 8 Main drain pipe 9 Bottom base 10 Ground 11 Sub drain pipe 12 Tip (Sub drain pipe)
13 Groundwater level 14 Bottom (sub drain pipe)
15 Drain pipe 16 Upper end (drain pipe)
17 Lower end (drain pipe)
18 Upper end (main drain pipe)
19 Water-permeable materials (crushed stones, pebbles, etc.)

Claims (5)

Open to the ground surface around roads, buildings, etc., bury a box made of cylindrical concrete in the ground, connect various pipes to the peripheral surface of the box, and cast iron in the opening on the ground surface In manholes for water, sewerage, electricity, communication, etc.
While the main drainage pipe with a plurality of small holes for water passage on the peripheral surface penetrates the bottom plate from the box, it is buried at the set depth of the ground below the bottom plate,
A secondary drainage pipe with a plurality of small holes for water flow on the peripheral surface is provided in the vertical direction along the outer periphery of the box, and the box peripheral wall at the tip is higher than the groundwater level of the ground around the box Pierce through and open into the box, and the lower end is buried at the set depth of the ground below the bottom,
A drain pipe is provided in the vertical direction along the inner wall of the box, and its upper end is connected to the vicinity of the opening at the tip, and its lower end is connected to the vicinity of the upper end of the main drain pipe,
When fluidization occurs due to an increase in the groundwater level due to an earthquake, etc., or due to an increase in the water pressure at the bottom of the box 3 and the surrounding water, the water from the bottom of the box and the surrounding liquefied soil is used as the main drain pipe and the sub drain pipe Introduced into both pipes through a large number of small holes, draining the introduced water into the box through the main drain pipe, drain pipe, and sub drain pipe, reducing the pressure to rise the manhole to the ground surface, An apparatus for preventing a manhole from rising due to a liquefaction phenomenon, which is provided to prevent the manhole from rising due to a liquefaction phenomenon. The manhole is not newly limited, existing, or large, small, shape, material, etc.,
The apparatus for preventing a manhole from floating due to the liquefaction phenomenon according to claim 1. At least one main drain pipe, sub drain pipe, and drain pipe are provided, and the main drain pipe and the sub drain pipe are provided with a small number of small water passage holes on the circumferential surface of a steel pipe or a PVC pipe having a set length. The drainage pipe is a steel pipe or a vinyl chloride pipe,
The apparatus for preventing a manhole from floating due to the liquefaction phenomenon according to claim 1. A main drainage pipe and a drain pipe are provided as a single pipe, and a plurality of small holes for water passage are provided in a peripheral surface of a portion corresponding to the main drain pipe.
The apparatus for preventing a manhole from floating due to the liquefaction phenomenon according to claim 1. When the main drain pipe and the sub drain pipe are embedded below the bottom of the box or around the box, each pipe is surrounded by a water-permeable material such as crushed stone and pebbles. It is characterized by
The apparatus for preventing a manhole from floating due to the liquefaction phenomenon according to claim 1.

Images