JP2023071087A - Buoyancy Counterpart and its Construction Method - Google Patents

Abstract

To prevent floating by buoyancy acting on an undersea tunnel without using heavy concrete.SOLUTION: A plurality of buoyancy counterparts 30 for preventing floating due to buoyancy acting on an undersea tunnel T are constructed at a plurality of locations inside the undersea tunnel T. The buoyancy counterpart 30 is formed of a reinforcing bar laminate 31 formed by piling up a plurality of reinforcing bars 31a, and a hardening material 32 placed so as to embed the reinforcing bar laminate 31 therein. Mortar using only sand as an aggregate is applied to the hardening material 32.SELECTED DRAWING: Figure 5

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buoyancy countermeasure part and its construction method, and more particularly to a technique for preventing floating due to buoyancy acting on an underwater structure or an underground structure.

Underwater structures such as undersea tunnels, which are tunnels built through the bottom of bodies of water such as rivers, canals, and seas, and underground structures built in the ground containing a large amount of groundwater (railroads, roads, water and sewage systems) , communication conduits), if the ceiling plate for the counterweight is removed, there is a risk that the underwater structure or the underground structure itself will float.

Also, in the construction of new underwater structures and underground structures, if the soil cover is small or the ground is very soft and the weight is not sufficient to resist the buoyancy, there is a possibility that the structure will float up. be.

Therefore, in the past, for example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2000-034158), for this reason, a pillar in a management area for performing maintenance and inspection provided at the bottom of a tunnel, which is an underground structure. There is known a technique for preventing the tunnel from rising by constructing a wall between the pillar and the heavy concrete whose specific gravity is increased by mixing iron powder or the like.

Here, when constructing the above-mentioned wall, in order to use as much heavy-weight concrete as possible to ensure the prevention of tunnel lifting, the amount of reinforcing bars placed in the formwork is the same as that of a general wall. Build less than that. Then, heavy concrete is poured into the formwork surrounding the reinforcing bars.

JP-A-2000-034158

When pouring heavy concrete, the heavy concrete is brought in while being stirred by a mixer truck (truck mixer), and the heavy concrete is pressure-fed by a concrete pump truck and poured into the formwork. For that purpose, the main road for general vehicles provided above the management area must be restricted to one lane, and mixer trucks and concrete pump trucks must be arranged to improve workability.

In addition, since the main line is regulated in this way, the construction work will be carried out at night when the traffic volume of general vehicles is relatively low. Then, since heavy concrete is special, it becomes difficult to obtain it when construction is done at night, and the supply itself becomes a problem.

Furthermore, to connect the main line at the top and the management area at the bottom, open the hatches provided at predetermined intervals and introduce pipes from the concrete pump truck into the management area (for example, the maximum length of the pipe is about 70m) to reduce the weight. Since the concrete will be placed, it is necessary to proceed with the work while communicating with the workers in the main line and the workers in the management area.

Heavy concrete does not mix cement with sand or gravel like normal concrete, but heavy aggregate with a high specific gravity such as iron ore or barium ore is mixed, so heavy concrete is mixed in the pipe during pumping. There is also a risk of troubles such as obstruction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned technical background, and it is an object of the present invention to provide a technique capable of preventing floating due to buoyancy acting on underwater structures and underground structures without using heavy concrete. and

In order to solve the above problems, the buoyancy countering portion of the present invention according to claim 1 is a buoyancy countering portion that prevents an underwater structure or an underground structure from floating due to buoyancy acting on the underwater structure. A reinforcing bar laminate constructed at one or more locations inside or inside the underground structure and formed by piling up a plurality of reinforcing bars, and a hardening material cast so as to embed the reinforcing bar laminate. characterized by being formed.

The buoyancy countering portion of the present invention described in claim 2 is characterized in that, in the invention described in claim 1, the reinforcing bars constituting the reinforcing bar laminate are arranged in parallel with each other with a predetermined interval in the horizontal direction. It is characterized in that they are intersected in different directions alternately.

According to claim 3, the buoyancy counteracting portion of the present invention is characterized in that, in the invention according to claim 1 or 2, the hardening material comprises cement paste and aggregate mixed in the cement paste. and

According to a fourth aspect of the present invention, there is provided a buoyancy countering portion according to the third aspect of the invention, wherein the hardening material is mortar using only sand as an aggregate.

The buoyancy countering portion of the present invention according to claim 5 is the buoyancy countering portion according to the invention according to claim 3 or 4, wherein the horizontal spacing of the reinforcing bars is wider than the maximum grain size of the aggregate. characterized by

The buoyancy countering portion of the present invention according to claim 6 is the buoyancy countering portion of the invention according to any one of claims 1 to 5, wherein the buoyancy countering portion is attached to the underwater structure or the underground structure at a predetermined interval. It is characterized in that it is constructed between a plurality of pillars provided.

According to claim 7, the buoyancy countering part of the invention according to claim 6 is characterized in that it is formed at the same height as the strut, and the curable material on the uppermost part has no shrinkage. and

The buoyancy counteracting portion of the present invention according to claim 8 is characterized in that, in the invention according to claim 6 or 7, the underwater structure or the underground structure has a main line area provided with a main line on which general vehicles run. is formed, and a road tunnel having the support on the lower side and a management area for performing maintenance and inspection of the structure is formed.

In order to solve the above problems, a method for constructing a buoyancy countering portion according to claim 9 of the present invention is a method for constructing a buoyancy countering portion that prevents floating due to buoyancy acting on an underwater structure or an underground structure. , in the inside of the underwater structure or the inside of the underground structure, four angle members are erected so that the corners of the chevron face outward to form four corners of a rectangle, and the inside of these angle members is regulated. Constructing a reinforcing bar laminate formed by stacking a plurality of reinforcing bars arranged parallel to each other with a predetermined interval in the horizontal direction and alternately crossing in different directions in the vertical direction, A formwork is assembled so as to surround the reinforcing bar laminate, a hardening material is cast into the formwork to embed the reinforcing bar laminate, and the formwork is removed after the hardening material hardens. characterized by

A method for constructing a buoyancy countering portion according to claim 10 of the present invention is characterized in that, in the invention according to claim 9, the underwater structure or the underground structure has a main line on which general vehicles run. It is a road tunnel in which an area is formed and a management area for maintenance and inspection of the structure having the support on the lower side is formed, and the buoyancy facing section is constructed using only the management area. It is characterized by

According to the eleventh aspect of the present invention, there is provided a method for constructing a buoyancy counterweight portion according to the ninth or tenth aspect of the invention, wherein the buoyancy counterweight is removed prior to removal of the counterweight in the renewal work of the underwater structure or the underground structure. It is characterized by constructing a counter part.

According to the present invention, a buoyancy counteracting portion formed of a reinforcing bar laminate formed by piling up a plurality of reinforcing bars and a hardening material cast so as to embed the reinforcing bar laminate is provided in an underwater structure. Since it is built inside or inside the underground structure, it is possible to prevent the underwater structure and the underground structure from floating due to buoyancy without using heavy concrete mixed with heavy aggregate.

FIG. 2 is a cross-sectional view showing the inside of the undersea tunnel during construction of the buoyancy countermeasure part, which is one embodiment of the present invention, from the extension direction. FIG. 2 is a plan view showing the lower part of the undersea tunnel of FIG. 1; FIG. 2 is a cross-sectional view taken along line AA of FIG. 1; FIG. 2 is a cross-sectional view from a radial direction showing a buoyancy countermeasure section constructed in the undersea tunnel of FIG. 1; FIG. 5 is a cross-sectional view showing an enlarged portion of symbol E in FIG. 4 ; FIG. 6 is a cross-sectional view taken along line BB of FIG. 5; 1 is a cross-sectional view showing the inside of an undersea tunnel in which a buoyancy counteracting section is constructed according to an embodiment of the present invention, viewed from the extending direction; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment as an example of the present invention will be described in detail below with reference to the drawings. In the drawings for describing the embodiments, in principle, the same components are denoted by the same reference numerals, and repeated description thereof will be omitted.

FIG. 1 is a cross-sectional view showing the inside of an undersea tunnel under construction of a buoyancy countermeasure part according to an embodiment of the present invention from the extension direction, FIG. 2 is a plan view showing the lower part of the undersea tunnel in FIG. 1, and FIG. 1 is a cross-sectional view taken along line AA, FIG. 4 is a cross-sectional view showing the buoyancy countermeasure section constructed in the undersea tunnel of FIG. 1 from the radial direction, and FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5, and FIG. 7 is a cross-sectional view showing the inside of the submarine tunnel in which the buoyancy counteracting section according to one embodiment of the present invention is constructed, from the extending direction. is.

It should be noted that the buoyancy counteracting section can be constructed in either the renewal work or the new construction work of the undersea tunnel. It shall be constructed prior to removal of the counterweight ceiling plate (counterweight) 11 .

In FIGS. 1 to 3, the submarine tunnel (underwater structure) T of the present embodiment constructed through the sea has a main line area t1 provided with a main line 10 on which general vehicles run on the upper side, and a main line area t1 on which ordinary vehicles run. A management area t2 for maintenance and inspection of the undersea tunnel T is formed on the side.

Above the main line area t1, a counterweight ceiling plate 11 for preventing the undersea tunnel T from rising and a dust collector ceiling plate 12 for forming an exhaust duct 12a are supported by suspension fittings 12b (FIG. 4). are provided. At the end of the dust collector ceiling plate 12, a dust collector 13 for sucking dust, exhaust gas, etc. from the undersea tunnel T and feeding it into the exhaust duct 12a is installed.

The management area t2 is divided into three areas, and as shown in FIG. area) 20, an equipment placement space (second lower area) 22, which is partitioned by a management passage 20 and a plurality of pillars 21 and in which various devices necessary for maintenance and inspection of the undersea tunnel T are placed, and a management It is composed of a passageway 20 and a tunnel (third lower area) 24 partitioned by a partition wall 23 and in which communication cables, power transmission lines, etc. are laid.

In this embodiment, the width of the support 21 provided along the extension direction of the undersea tunnel T is 350 mm, and the distance between the support 21 and the support 21 is 3150 mm. However, the dimensions of the column 21 can be freely set, and are not limited to the numerical values shown in this embodiment.

Further, in this embodiment, as shown in FIG. 3, in the radial cross section of the undersea tunnel T, the management passage 20 is in the center, the equipment installation space 22 is provided on the right side thereof, and the tunnel passage 24 is provided on the left side thereof. are provided, but are not limited to these positional relationships. Furthermore, it is sufficient if the area is partitioned into a plurality of areas via the pillars 21, and it is not necessary to partition the area into three or more areas or to provide the partition wall 23.

In the renewal work of the undersea tunnel T, if the existing counterweight ceiling plate 11 is removed for renewal of the inner wall of the tunnel, the weight balance of the undersea tunnel T with respect to the buoyancy may be lost and the tunnel may float. Therefore, in order to construct the buoyancy countering portion 30 (FIGS. 4 and 5) that prevents such floating, necessary materials (reinforcing bars, cement , aggregate, water, formwork (conpanel), etc.), and a small crawler crane CC that supports the car body with four folding outriggers.

Next, the buoyancy countering portion 30 of this embodiment will be described with reference to FIGS. 4 to 7. FIG.

The buoyancy countering portion 30 of the present embodiment is provided inside the undersea tunnel T, specifically, as shown in FIG. and the strut 21. However, if the buoyant force countering portion 30 is constructed between all the pillars 21, the management passage 20 and the equipment arrangement space 22 are blocked, and an excessively large number of buoyant force countering portions 30 are constructed continuously. As a result, when a worker comes and goes between the management passage 20 and the equipment installation space 22, there is a risk that the worker will have to make a detour and be inconvenient. Therefore, if the buoyant force countering portion 30 can secure a predetermined weight, a portion where the buoyant force countering portion 30 is not constructed may be provided at an appropriate interval between the columns 21 (see FIG. 7).

In this embodiment, the buoyancy countering portion 30 is thicker than the support 21 (see FIGS. 3 and 4), but the support 21 and the buoyancy countering portion 30 have the same thickness or The strut 21 may be thicker than the buoyancy countering portion 30 . In the present embodiment, the buoyancy countering portion 30 is constructed between the pillars 21 and 21 , but it may be constructed at a location other than between the pillars 21 and 21 .

Now, as shown in FIG. 5, the buoyancy countering portion 30 consists of a reinforcing bar laminate 31 formed by stacking a plurality of reinforcing bars 31a in multiple stages, and a hardening material cast so as to embed the reinforcing bar laminate 31. 32 and

In the present embodiment, the reinforcing bar 31a constituting the reinforcing bar laminate 31 of the buoyancy countering portion 30 is a deformed reinforcing bar of D32 (diameter 32 mm) (a bar-shaped reinforcing bar in which uneven protrusions are formed on the surface by rolling steel). used. Further, as shown in FIGS. 5 and 6, the reinforcing bars 31a are arranged in parallel with each other with a predetermined interval (for example, 5 cm pitch) in the horizontal direction, and perpendicularly arranged in the vertical direction. Note that the size and type of the reinforcing bar 31a are not limited to those described above, and can be freely selected. Further, the horizontal spacing of the reinforcing bars 31a does not need to be 5 cm pitch, and it is sufficient that the reinforcing bars 31a are alternately arranged in different directions in the vertical direction to intersect each other, and they do not have to be orthogonal.

The curable material 32 in which the reinforcing bar laminate 31 is embedded is composed of a cement paste obtained by kneading water and cement, and an aggregate mixed in the cement paste. The horizontal spacing of the reinforcing bars 31a described above is wider than the maximum grain size of the aggregate so that the hardening material 32 spreads over the entire interior of the reinforcing bar laminate 31. As shown in FIG.

As the aggregate, gravel (coarse aggregate) or sand (fine aggregate) can be used, but it is desirable to use only sand. This is because the cement paste does not contain gravel, which is a coarse aggregate (that is, only sand, which is a fine aggregate), so that the sand can pass through the gap between the reinforcing bars 31a. This is because the reinforcing bars 31a can be densely arranged, and the reinforcing bar laminate 31 can be made heavy.

Also, in the case of concrete using sand as aggregate, the mixer truck must be driven into the undersea tunnel, but it is often impossible to drive into the management passage 20 due to space constraints. In other words, in the case of concrete, a mixer truck is driven into the main line 10 on the upper side, a hatch communicating with the lower side is opened, and concrete is pumped and poured by a concrete pump car. There is a need for lane control and for communication between the worker on the side of the main line area t1 and the worker on the side of the management area t2 regarding the progress of work. On the other hand, in the case of mortar using only sand as the aggregate, if the mortar material (cement, sand, water) is brought in by truck V that has entered the management passage 20, the operator can manually This is because the mortar can be prepared by kneading these together and can be placed in the mortar.

Here, construction of the buoyancy countering portion 30 will be described with reference to FIGS. 5 and 6. FIG.

When constructing the reinforcing bar laminate 31, first, four angle members (equivalent angle steel) 33 are attached so as to form the four corners of the rectangular reinforcing bar laminate 31 in plan view (FIG. 6), and the corners of the angle are attached to the outside. set up facing the In addition, the angle member 33 is installed by welding to an anchor embedded in the bottom surface of the undersea tunnel T side, for example.

Next, the reinforcing bars 31a are horizontally arranged in parallel with each other at predetermined intervals so as to be regulated inside the angle members 33, and arranged alternately in the vertical direction at right angles. A reinforcing bar laminate 31 formed by piling up the reinforcing bars 31a is constructed. Specifically, using a long ruler or a long plate with markings at predetermined intervals (in the case of the present embodiment, the interval between the reinforcing bars 31a is 5 cm), four angles are drawn. Reinforcing bars 31a are laid out horizontally at predetermined intervals in a region surrounded by the material 33. - 特許庁Subsequently, the reinforcing bars 31a are horizontally laid out at predetermined intervals on the laid reinforcing bars 31a so as to be orthogonal to the reinforcing bars 31a. This is sequentially repeated to construct a reinforcing bar laminate 31 in which a plurality of reinforcing bars 31a are piled up.

Once the rebar laminate 31 is constructed, a formwork (not shown) is assembled to surround the rebar laminate 31 . Then, the curable material 32 described above is placed in the mold to embed the reinforcing bar laminate 31 therein. At this time, if post-construction anchors are installed on the struts 21 and the bottom, it becomes possible to firmly integrate the buoyancy countermeasure section 30 to be constructed and the submarine tunnel T, which is an existing structure.

Here, the buoyancy facing portion 30 can also be formed in a state in which a gap is provided between the column 21 and the ceiling surface.

In addition, as shown in FIG. 5, when the hardening material 32 is poured up to the ceiling surface of the management area t2 to form the buoyancy countering portion 30 at the same height as the support 21, the uppermost hardening material 32 It is desirable to use non-shrinking mortar (for example, non-shrinking mortar).

In this way, the non-shrinking hardening material 32 hardens in the shape at the time of placement, so that the upper part of the buoyancy countering portion 30 (that is, between the upper surface of the buoyancy countering portion 30 and the ceiling surface) This is because the adhesiveness to the ceiling surface is enhanced and integrated with the ceiling surface without forming a gap between them, and the durability can be improved.

Finally, when the curable material 32 placed in the mold has hardened, the mold is removed. Thereby, the buoyancy countering portion 30 shown in FIGS. 5 and 6 is formed.

Such a buoyancy countering section 30 is constructed between the pillars 21 provided in the management area t2 along the extension direction of the undersea tunnel T. As shown in FIG. As shown in FIG. 7, in the present embodiment, a portion where the buoyancy countering portion 30 is constructed and a portion where the buoyancy countering portion 30 is not constructed are continuous between the struts 21 and 21, respectively. By doing so, even when the worker goes back and forth between the management passage 20 and the equipment installation space 22, the worker only takes a detour, and the workability is not hindered.

Note that the construction pattern of the buoyancy countering portion 30 is not limited to the present embodiment, such as alternating locations where the buoyancy countering portion 30 is constructed and locations where it is not constructed. Also, in the present embodiment, the buoyancy countering portion 30 is constructed at a plurality of locations, but it may be constructed at only one location.

As described above, according to the present embodiment, the reinforcing bar laminate 31 is formed by stacking a plurality of reinforcing bars 31a, and the hardening material 32 is placed so as to embed the reinforcing bar laminate 31. Since the buoyancy countering part 30 is built inside the undersea tunnel T, it is possible to prevent the uplift due to the buoyancy acting on the undersea tunnel T without using heavy concrete mixed with heavy aggregate. Become.

As a result, it is possible to construct the buoyancy facing portion 30 using only the management area t2 formed below the undersea tunnel T. FIG. Therefore, as in the case of pumping and placing heavy concrete, the main line 10 provided in the main line area t1 formed on the upper side of the undersea tunnel T for general vehicles to run is regulated, and workability is improved. It is no longer necessary to arrange a mixer truck or a concrete pump truck by devising it so that it becomes.

In addition, since there is no need to restrict lanes on the main road 10, construction work can be carried out even at night when the traffic volume of general vehicles is relatively low. You don't have to.

In addition, since it is not necessary to open the hatch to connect the upper main line area t1 and the lower management area t2 and introduce pipes from the concrete pump vehicle into the management area, the workers in the main line area t1 and the lower management area t2 There is no need to proceed with the work while communicating with the worker in the management area t2.

In addition, since the heavy aggregate (iron ore, barium ore, etc.) with a high specific gravity is mixed in the heavy concrete, troubles such as clogging of the heavy concrete in the pipes during pumping do not occur.

Furthermore, since the buoyancy countering portion 30 is formed of the reinforcing bar laminate 31 formed by stacking a plurality of reinforcing bars 31a, the desired weight is obtained even with a relatively thin thickness, so the buoyancy countering portion 30 The constructed wall thickness can be thin. As a result, the width of the passage can be ensured, and the workability in terms of maintenance and management is not deteriorated due to the wall thickness becoming thick.

Although the invention made by the present inventor has been specifically described based on the embodiments, the embodiments disclosed in this specification are illustrative in all respects and are limited to the disclosed technology. isn't it. That is, the technical scope of the present invention should not be construed in a restrictive manner based on the description of the above embodiments, but should be construed according to the description of the scope of claims. All modifications are included as long as they do not deviate from the description technology and equivalent technology and the gist of the claims.

For example, the rectangle that expresses the shape of the reinforcing-bar laminate 31 in plan view is not limited to the rectangle as shown in FIG. 6, but also includes a square.

In the above description, the case where the present invention is applied to the construction of the buoyancy countermeasure section during the undersea tunnel renewal work has been described. However, the present invention is applicable not only to submarine tunnels (tunnels), but also to various underwater structures constructed under the bottom of water areas such as rivers, canals, and the sea, and various structures constructed in the ground containing a large amount of groundwater. It can be widely applied to renewal work and new construction work of underground structures (tunnels, water supply and sewerage, communication pipelines).

10 Main line 11 Ceiling plate for counterweight 12 Ceiling plate for dust collector 20 Passage for management 21 Strut 22 Equipment arrangement space 23 Partition wall 24 Tunnel 30 Buoyancy countering part 31 Rebar laminate 31a Reinforcement bar 32 Hardening material 33 Angle material CC Crawler crane T Undersea tunnel (underwater structure)
V Track t1 Main line area t2 Management area

Claims (11)

A buoyancy counteracting part that prevents floating due to buoyancy acting on an underwater structure or an underground structure,
constructed at one or more locations inside the underwater structure or inside the underground structure,
It is formed of a reinforcing bar laminate formed by stacking a plurality of reinforcing bars, and a hardening material cast so as to embed the reinforcing bar laminate,
A buoyancy counteracting part characterized by: The reinforcing bars constituting the reinforcing bar laminate are
They are arranged parallel to each other with a predetermined interval in the horizontal direction, and arranged crosswise in different directions alternately in the vertical direction,
2. The buoyancy countering portion according to claim 1, characterized in that: The curable material consists of a cement paste and an aggregate mixed in the cement paste,
3. The buoyancy countering portion according to claim 1 or 2, characterized in that: The curable material is mortar using only sand as an aggregate,
4. The buoyancy countering portion according to claim 3, characterized in that: The horizontal spacing of the reinforcing bars is wider than the maximum grain size of the aggregate,
5. The buoyancy countering portion according to claim 3 or 4, characterized in that: The buoyancy countering portion is
It is constructed between a plurality of pillars provided at predetermined intervals on the underwater structure or the underground structure,
The buoyancy countering portion according to any one of claims 1 to 5, characterized in that: The buoyancy countering portion is
It is formed at the same height as the support, and the uppermost curable material has no shrinkage.
7. The buoyancy countering portion according to claim 6, characterized in that: The underwater structure or the underground structure,
A road tunnel in which a main line area is formed on the upper side with a main line on which general vehicles run, and a management area is formed on the lower side for maintenance and inspection of the structure, having the pillars.
8. The buoyancy countering portion according to claim 6 or 7, characterized in that: A method for constructing a buoyancy counteracting section for preventing floating due to buoyancy acting on an underwater structure or an underground structure,
Inside the underwater structure or the underground structure, four angle members are erected so that the corners of the chevron face outward to form four corners of a rectangle, and the inside of these angle members is regulated. A reinforcing bar laminate is constructed by stacking a plurality of reinforcing bars arranged parallel to each other with a predetermined interval in the horizontal direction and alternately crossing in different directions in the vertical direction,
Assemble a formwork to surround the reinforcing bar laminate,
Casting a curable material in the formwork to embed the reinforcing bar laminate,
removing the formwork after the curable material has cured;
A method for constructing a buoyancy counteracting section characterized by: The underwater structure or the underground structure has a main line area on the upper side on which a main line on which general vehicles run is formed, and a management area for maintenance and inspection of the structure having the support on the lower side. is a road tunnel formed by
The buoyancy facing part is constructed using only the management area,
The construction method of the buoyancy countering portion according to claim 9, characterized in that: constructing the buoyancy-counterpart prior to removing the counterweight in the renewal work of the underwater structure or the underground structure;
11. The construction method of the buoyancy countering portion according to claim 9 or 10, characterized in that:

Images