JP5123784B2 - Manhole levitation suppression device - Google Patents

Description

  The present invention relates to a manhole levitation suppression device, and more particularly to an apparatus for preventing a manhole from rising due to ground liquefaction when an earthquake occurs.

  In the case of many large-scale earthquakes that occurred in the past, manholes buried in the ground have risen to the surface of the earth, and the situation such as the destruction of water and sewage and the passage of emergency cars for relief Was invited.

This manhole lift phenomenon occurs when the ground is loose and the groundwater level is high, when the earthquake occurs, the pore water pressure in the ground rises and becomes excess pore water pressure, and this excess pore water pressure pushes up the manhole. It is considered a thing.
JP-A-2005-24896 None

  Conventionally, in order to prevent this floating phenomenon, a method of injecting and solidifying cement milk at the lower and lower ends of the manhole to obtain resistance between the ground and the ground has been used. It was not a sufficient measure because it often peeled off due to aging and eventually became unable to withstand earthquakes.

  In addition, a plurality of excess pore water pressure dissipation valves that are not opened by hydrostatic pressure but are opened only when excess pore water pressure is applied are installed at various locations on the peripheral wall of the manhole. Attempts have also been made to suppress the floating of underground structures, but they have not yet been fully effective, and have not been the fundamental solution.

For this reason, the present inventor has proposed, as Japanese Patent Application No. 2007-80906, an underground buried object levitation suppression device that effectively suppresses the floating of underground objects such as manholes.
This underground structure levitation restraint device rotates and propels a winged anchor to a fixing layer with sufficient ground strength, fixes it there, and connects the manhole and this winged anchor with an anchor fixing shaft to strengthen the manhole. It can be applied to not only new facilities but also existing facilities without any problems, effectively preventing manhole lift due to earthquakes. It has the effect of securing lifelines such as water and sewage systems and passages for rescue vehicles and minimizing the expansion of earthquake damage.

  However, when an earthquake occurs, the manhole may swing not only in the vertical direction but also in the horizontal direction. However, in the underground structure floating suppression device proposed as Japanese Patent Application No. 2007-80906, There is no particular consideration, the anchor fixing shaft cannot follow the horizontal movement of the manhole at the time of the earthquake, abnormal stress is applied to the connecting part of this anchor fixing shaft and anchor, and the connecting part is damaged, There was a possibility that the manhole could not be prevented from rising.

  Therefore, as a result of research conducted by the present inventor to cope with horizontal shaking, the horizontal vibration applied from the anchor fixing shaft to the manhole is buffered in the event of an earthquake, and the manhole is effectively prevented from rising. We have succeeded in developing a manhole levitation suppression device that can be proposed as the present invention.

  The start side of the hanger member, in which a horizontally long guide through hole is formed, is fixed to at least a pair of opposed desired positions on the conical inclined surface of the manhole head, and is positioned in the fixing layer of the ground. By fixing the upper end of the anchor fixing shaft whose lower end is fixed to the anchor to a fixing plate slidably mounted so as to straddle the upper side edge of the hanger member, a manhole levitation suppression device is configured, Solved the above problem.

  At this time, the hanger member is coupled to the manhole by fitting a pipe ring formed by winding a steel pipe around the conical inclined surface of the head of the manhole, or a belt-like ring formed by cutting the steel pipe. The hanger member is fixed to at least a pair of opposed side surfaces of the hanger, or the base plate is fixed to the start end side of the hanger member, and the base plate is directly fixed to the conical inclined surface of the head of the manhole.

  The upper end of the anchor fixing shaft with the lower end fixed to the anchor is fixed to the hanger member via the fixing plate. In this state, an earthquake occurs and the manhole is lifted by the vertical shaking. When trying to lift, the levitating force is transmitted to the anchor fixing shaft via the hanger member, but the levitating force of the anchor fixed to the anchoring layer of the ground is reduced, and the lifting of the manhole is prevented.

  At this time, even if horizontal shaking occurs, the anchor fixing shaft is slidably fixed to the hanger member via the fixing plate, so that the fixing plate slides laterally in response to the horizontal shaking. As a result, the anchor fixing shaft does not follow the horizontal swing, the bending stress is not applied to the anchor, and there is no possibility that the anchor fixing shaft and the anchor may be damaged at the connecting portion. In addition, in the case where a ring pipe or a belt-like ring is fitted into the manhole head, there is no need to provide an opening or a through-hole on the manhole wall surface for fixing, so the manhole strength is completely affected. In addition, there is no risk of impairing the water-stopping property. In particular, in the case of fitting a pipe ring, the work at the site is extremely simple, and high-quality construction work can be performed quickly and reliably. In addition, since the upper end of the anchor fixing shaft is slidably fixed to the guide through hole of the hanger member through a fixing plate, the allowable range is large in the horizontal direction, and installation errors during construction of the anchor can be absorbed. It has the effect that construction work is easy and has extremely high practicality.

  A horizontally long guide through hole is provided inside the hanger member, and the upper end of the anchor fixing shaft is fixed to the hanger member via a fixing plate placed on the guide through hole so that the anchor fixing shaft can slide in the horizontal direction. The biggest feature is in the point.

FIG. 1 is a side view of a manhole levitation suppression apparatus according to a first embodiment of the present invention in a state where it is actually installed in the ground, FIG. 2 is a side view of the main part thereof, and FIG. 3 is an enlarged perspective view thereof.
In the figure, reference numeral 1 denotes a pipe ring in which a steel pipe is wound and both ends thereof are welded to form an annular shape, and has an inner diameter that matches the outer diameter at a desired position of the conical inclined surface 3 of the head 2 of the manhole 20. It fits into the conical inclined surface 3 exactly. Further, in this embodiment 1, the pipe ring 1 is constituted by winding two steel pipes, but if there is no problem in strength, it may be constituted by one steel pipe, and conversely if it is desired to increase the strength. You may comprise with three or more steel pipes.

A pair of arm members 4 having a thick plate shape toward the outside are fixed to at least two locations on the outer periphery of the pipe ring 1 so as to be sandwiched between the pair of arm members 4. A pair of hanging pieces 5 having a thick plate shape are pivotally supported downward. In the figure, 6 is a pivot shaft that pivots the upper part of the hanging piece 5 on the arm member 4. Further, from the lower end of the hanging piece 5, a thick steel plate is combined in a box shape toward the outside, and a hanger member 8 having a horizontally long guide through hole 7 is extended.
A reaction force plate 9 that abuts against the side wall surface of the manhole 20 is attached to the inner end of the hanger member 8.

  The upper end side of the anchor fixing shaft 10 is inserted into the guide through hole 7 of the hanger member 8, and the fixing plate 12 is slidably mounted so as to straddle the pair of upper edges of the hanger member 8. It is fastened and fixed with a nut 19.

  The lower end of the anchor fixing shaft 10 is fixed to the anchor 11 positioned on the fixing layer 22 of the ground 21. In this embodiment, a winged anchor is used as the anchor 11. However, the anchor is not necessarily a winged anchor, and the type of the anchor is not particularly limited as long as the anchor has a pulling resistance.

  Moreover, in the said Example, although the pipe ring 1 which wound the steel pipe was used, as shown in FIG.4 and FIG.5, you may use the strip | belt-shaped ring 13 which cut the suitable steel pipe into the short shape. . However, when the belt-like ring 13 is used, since a gap is partially formed between the conical inclined surface 3 of the head 2 of the manhole 20, a wedge-shaped bearing block 14 is interposed between the gaps. Therefore, make sure that the load is even.

  On the other hand, in the embodiment shown in FIGS. 6 and 7, the hanger member 8 is directly fixed to the wall surface of the head 2 of the manhole 20 without using the pipe ring 1 or the belt-like ring 13 as in the case of the above embodiments. The base plate 15 is fixed to the start end side of the hanger member 8, the bolt 18 is inserted between the base plate 17 applied to the corresponding position of the inner wall surface 16 of the head 2 of the manhole 20, and the nut 19 is tightened The hanger member 8 is fixed to the head 2 of the manhole.

  Example 1 has the structure as described above, and the upper end side of the anchor fixing shaft 10 having the lower end fixed to the anchor 11 is fixed to the hanger member 8 via the fixing plate 12, and is used. In this state, when an earthquake occurs and the manhole 20 is lifted by a vertical swing, the levitation force is transmitted to the anchor fixing shaft 10 via the hanger member 8, but is fixed to the fixing layer 22 of the ground 21. The levitation force is reduced by the pulling-out resistance of the anchor 11 and the manhole 20 is prevented from rising.

  At this time, even if horizontal shaking occurs, the anchor fixing shaft 10 is slidably fixed to the hanger member 8 via the fixing plate 12, so that the fixing plate 12 is laterally moved in response to the horizontal shaking. As a result, the anchor fixing shaft 10 does not follow the horizontal swing, the anchor 11 is not subjected to excessive bending stress, and the anchor fixing 10 and the anchor 11 may be damaged at the connecting portion. Absent. In particular, in the case where the pipe ring 1 is fitted, the work at the site is extremely simple, and high-quality construction work can be performed quickly and reliably. Also, in the case where the ring pipe 1 or the belt-like ring 13 is fitted into the manhole head 2, there is no need to provide an opening or a through hole on the wall surface of the manhole for fixing, so the manhole strength is completely improved. There is no impact and there is no risk of impairing waterstop. Further, since the upper end of the anchor fixing shaft 10 is slidably fixed to the guide through hole 7 of the hanger member 8 via the fixing plate 12, the allowable range is large in the horizontal direction and the installation error when the anchor 11 is constructed is absorbed. It has an effect such that it can be performed and the construction work is easy, and has extremely high practicality.

  It is very useful as an earthquake countermeasure for manholes.

The side view of the state which actually installed Example 1 of the manhole levitation restraint device concerning this invention in the ground. The side view of the principal part. Similarly, the expansion perspective view of the principal part. The partial side view of the Example which replaced with the pipe ring shown in FIG. 1 and used the strip | belt-shaped ring. Similarly, a perspective view of a belt-shaped ring. The fragmentary sectional view of the principal part of the Example which fixed the hanger member directly to the head side wall surface of the manhole. Similarly, the enlarged plan view of the principal part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe ring 2 Manhole head 3 Conical inclined surface 4 Arm material 5 Hanging piece 6 Pivoting shaft 7 Guide through-hole 8 Hanger member 9 Reaction force plate 10 Anchor fixing shaft 11 Anchor 12 Fixing plate 13 Strip ring 14 Supporting block 15 Base plate 16 Inner wall surface 17 Base plate 18 Bolt 19 Nut 20 Manhole 21 Ground 22 Fixing layer

Claims (3)

  A hanger in which a steel pipe is wound around a conical inclined surface of a manhole head and a ring-shaped pipe ring is fitted, and at least a pair of opposed side surfaces of the pipe ring are formed with horizontally long guide through holes. The start end side of the member is fixed, and the upper end of the anchor fixing shaft whose lower end is fixed to the anchor positioned in the fixing layer of the ground is slid so as to straddle the upper side edge of the guide through hole of the hanger member. A manhole levitation suppression device characterized by being fixed to a fixed plate placed freely.   A belt-like ring made of a steel pipe is fitted into the conical inclined surface of the head of the manhole, and at the pair of opposed side surfaces of the belt-like ring, a laterally long guide through hole is formed at the start side of the hanger member The upper end of the anchor fixing shaft whose lower end is fixed to the anchor positioned in the fixing layer of the ground is slidably placed so as to straddle the upper side edge of the guide through hole of the hanger member. A manhole levitation suppression device characterized by being fixed to a fixed plate.   A base plate is fixed to the start end side of the hanger member in which a horizontally long guide through hole is formed, and this base plate is fixed to the conical inclined surface of the head of the manhole, and the anchor is positioned in the fixing layer of the ground. The upper end of the anchor fixing shaft, the lower end of which is fixed, is fixed to a fixing plate slidably mounted so as to straddle the upper side edge of the guide through hole of the hanger member. apparatus.

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