JPH05321510A - Construction method for underground tank - Google Patents

Abstract

PURPOSE:To make it possible to build an underground tank without any danger of collapse of the surrounding subsoil and in a short period of work, and further more, build the tank deep underground and hence make the best use of land. CONSTITUTION:A main wall core member 3 and a sub-wall core member 4 are built in on a main shaft 1 and a sub shaft excavated on a subsoil 6. Joint arms 9 on the side of the sub-core member are fitted into hollow joints on the side of the main wall core member from the longitudinal direction by way of slits 8. A grout material 5 is filled up in hollow sections formed between the main wall core member 3, the sub-wall core section and each hollow section of the hollow joints 10, the main shaft 1 and the sub-shaft 2, thereby building a side wall section 12. The sub-soil inside the side wall section is excavated and the grout material is applied, thereby building a bottom section 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground tank used as a heat storage tank for hot water, cold water or the like, or a water storage tank for adjusting the outflow of a river.

[0002]

2. Description of the Related Art In the conventional general method of constructing an underground tank, after excavating the construction site by excavating the excavator or other excavating machine after earth retaining work such as steel sheet pile construction or continuous underground wall construction. To do. After that, the work of assembling the rebar, the work of assembling the formwork and the work of placing the concrete are performed in the excavation hole to build an underground tank consisting of a reinforced concrete side wall part and a bottom plate part, and finally the outer circumference of the underground tank Backfill.

However, in the conventional method performed by this excavation method, since the underground tank is built near the ground surface, the area occupied by the tank on the ground surface increases as the design volume of the underground tank increases. Since the area of construction-related land such as material yard will be significantly widened, it will be difficult to build a large underground tank in urban areas where traffic is extremely congested and land prices are skyrocketing. is there.

In the conventional method, since the earth retaining work and the excavation work are carried out, the bar arrangement work, the formwork work and the concrete placing work are carried out, so that the work process is increased and a long construction period is required. Also,
In the case of building on soft ground, a ground improvement chemical is often injected in order to prevent collapse of the ground around the excavated part in the excavation method, but there is also a problem such as the adverse effect of this chemical injection on groundwater.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to construct a large-scale underground tank even in soft ground without risk of collapse of the surrounding ground safely and in a short construction period, and withstand strength of side walls. Since it is large and can be built in deep underground, it is to provide a method for constructing an underground tank that enables large-scale underground tanks to be constructed reasonably in urban areas and enables effective use of land.

[0006]

In the following, the construction method of the present invention will be described with reference to the accompanying drawings. In the construction method of the present invention, a plurality of main vertical holes 1 are formed along the circumferential direction of the underground tank to be constructed. 6, the main wall core member 3 having hollow joints 10 projecting in the longitudinal direction on both sides is built in the main vertical hole 1, and the sub vertical hole 2 is drilled in the middle of the main vertical holes 1 and 1. Then, the sub-wall core member 4 having joint arms 9 projecting in the longitudinal direction on both sides is built in, and the joint arms 9 of the sub-wall core member 4 are adjacent to the main wall core member 3.
The hollow joint 10 of the hollow joint 10 has a slit 8 in the longitudinal direction of the hollow joint 10.
Through the longitudinal direction.

The hollow portion in the longitudinal direction of the main wall core member 3, the hollow portion in the longitudinal direction of the hollow joint 10, the hollow portion in the longitudinal direction of the sub wall core member 4 itself or the sub wall core member 4 and the main wall core member. 3 and the hollow joint in the longitudinal direction formed between the hollow joint 10 and the main vertical hole 1 and the secondary vertical hole 2 are filled with the grout material 5 to construct the side wall portion 12, and the required root of the side wall portion 12 is formed. The inner ground of the side wall portion 12 is excavated leaving the insertion depth, and a grout material is cast on the excavated bottom surface portion to build the bottom board portion 7.

[0008]

Operation: The side wall 12 of the underground tank constructed in this way
Then, a plurality of adjacent main wall core members 3 and sub-wall core members 4 are interconnected by fitting the hollow joint 10 and the joint arm 9 through the slits 8 to form a chain skeleton body. The main wall core member 3, the sub wall core member 4, the hollow joints in the longitudinal direction of the hollow joint 10 and the grout material 5 filled in the main pit 1 and the sub pit 2 are hardened to be tightly coupled and integrated. To form a cylindrical structure. This side wall 12
Withstands large earth pressure and groundwater pressure received from the surrounding ground,
It has great strength against bending moment and shearing force that are exerted by these lateral pressures.

[0009]

1 to 7, the main wall core member 3 and the sub wall core member 4 are made of steel pipe, and the hollow joint 10 made of a small diameter steel pipe is provided over the entire length of the side face of the main wall core member 3. The joint arm 9 made of steel plate is fixed by welding, and is fixed by welding over the entire side surface of the sub-wall core member 4. The tip end of the joint arm 9 is formed in a T shape so that the joint arm 9 does not come out of the hollow joint 10 in the circumferential direction of the underground tank after being fitted into the hollow joint 10. Hollow joint 1
The 0 slit 8 is formed over the entire length of the side surface.

After the guide groove, which serves as a reference for excavating the main pit, is preliminarily excavated on the ground 6 with a backhoe or the like, as shown in FIG. 3, the main pit 1 is formed by an appropriate means such as a hydrophrase excavator.
To the required depth. The main wall core member 3 is built in the main vertical hole 1 so that the hollow joints 10 on both sides are arranged in the circumferential direction of the underground tank. When the length of the underground tank to be built is short, only one main wall core member 3 having a predetermined length is built, but when the length of the underground tank is long, a plurality of main wall core members 3 are built. Are sequentially built in the main vertical hole 1 while being connected by welding.

As shown in FIG. 4, the hollow joint 10 is fitted with an embolus cylinder 11 that completely closes the slit 8 from the inside. The outer surface of the cylinder 11 is covered with plastic, polyethylene or the like. When using a plurality of cylinders 11, the upper and lower cylinders 11 are screwed and connected. When the gap between the main wall core member 3 and the hole wall of the main vertical hole 1 is filled with the grout material 5, the embedding cylinder 11 prevents the grout material 5 from entering the hollow portion in the longitudinal direction of the hollow joint 10. It

As shown in FIG. 5, the grout material 5 is also filled in the hollow portion in the longitudinal direction of the main wall core member 3. As a result, the composite column 13 in which the main wall core member 3 and the hardened grout material layer are tightly coupled and integrated is built. Another main vertical hole 1 is provided at a predetermined distance from the synthetic cylinder 13 in the circumferential direction of the underground tank.
Was excavated, the main wall core member 3 was installed, and the grout material 5 was
Are sequentially filled, and a second synthetic column 13 is built. Thereafter, the required number of synthetic cylinders 13 are similarly arranged in an annular shape to be built.

After the grout material 5 is hardened as shown in FIG. 6, the embolus cylinder 11 is pulled out from the hollow joint 10 and removed. Hollow joints 1 of adjacent synthetic columns 13 facing each other
Insert a guide member of a suitable excavator into the hollow portion of 0,
The auxiliary vertical hole 2 is excavated in the intermediate portion of the adjacent synthetic cylinders 13. The sub pit 2 is excavated so as to partially overlap the main pits 1 and 1 on both sides.

As shown in FIG. 7, a required number of auxiliary wall core members 4 are built in the auxiliary vertical hole 2 while being sequentially connected by welding. At the time of this installation, the joint arm 9 on the sub-wall core member 4 side passes through the slit 8 and the hollow joint 1 on the main-wall core member 3 side.
It fits in 0. After that, the grout material 5 is filled in the hollow portion in the longitudinal direction of the hollow joint 10, the hollow portion in the longitudinal direction of the sub wall core member 4, and the hollow portion between the sub wall core member 4 and the hole wall of the sub vertical hole 2. To be done. As a result, the composite column 14 in which the sub-wall core member 4 and the hardened grout material layer are tightly bonded and integrated is constructed.

Although the synthetic cylinders 14 have a smaller diameter than the synthetic cylinders 13, all the synthetic cylinders 13 are connected by the interposition of these synthetic cylinders 14, so that the plurality of main wall core members 3 and sub-wall core members 4 are hollow. A cylindrical side wall portion 12 having a chain-like skeleton body connected to the joint 10 and the joint arm 9 in the core portion is obtained. The inside ground of the side wall 12 is the side wall 12
Excavation is carried out leaving a necessary rooting depth, and the bottom plate portion 7 is constructed by driving the grout material 5 to a required thickness on the excavation bottom surface portion. In addition, if necessary, the bottom plate portion 7 may be reinforced concrete structure by reinforcing bars.

In the above-mentioned embodiment, while the main vertical holes 1 are excavated one by one, the main wall core member 3 is built and the grout material 5 is filled to construct the composite column 13, and then the secondary vertical holes 2 are formed. While digging one by one, the sub-wall core member 4 is built and the grout material 6 is filled to build the composite column 14, but depending on the property of the ground 6, the main vertical hole 1 Alternatively, the main wall core member 3 and the sub wall core member 4 may be built after excavating the auxiliary vertical hole 2, and finally the grout material 5 may be filled at once.

In another embodiment shown in FIG. 8, the main wall core member 3 is made of steel pipe, and two hollow joints 10 made of small diameter steel pipe are welded in parallel over the entire side surface of the main wall core member 3. There is. The slit 8 of the hollow joint 10 is formed over the entire length of the side surface. The sub-wall core member 4 is composed of an assembled shaped steel obtained by welding a steel plate so as to have an H-shaped cross section. The two joint arms 9 are formed by extension portions of the two flange portions of the assembled shaped steel. The tip of each joint arm 9 is formed in a T-shaped cross section so as not to come off from the slit 8.

In this embodiment, the main vertical hole 1 is first excavated, then the main wall core member 3 is built and the grout material 5 is filled. Similarly, after the sub pit 2 is excavated, the sub wall core member 4 is built and the grout material 5 is filled. The sub vertical holes 2 are formed by connecting three small diameter holes in a straight line. The grout material 5 includes two hollow joints 1
0 and the web portion of the sub-wall core member 4 are filled in the hollow portion in the longitudinal direction. In this embodiment, there is no equivalent to the composite column 14 in the above-mentioned embodiment, and the composite column 13 is directly connected by the sub-wall core member 4. Since the main wall core member 3 and the sub wall core member 4 are connected by the two sets of hollow joints 10 and joint arms 9, the joint strength is increased.

In yet another embodiment shown in FIG. 9, the main wall core member 3 is made by assembling and welding steel plates so that the main wall core member 3 has a box-shaped cross section bent in a V shape at the center. The hollow joint 10 made of a small-diameter steel pipe is welded over the entire length to the extended portion of the two steel plates for long sides of the box-shaped cross section. Hollow joint 1
The 0 slit 8 is formed over the entire length of the side surface. The sub-wall core member 4 is composed of an assembled shaped steel obtained by welding a steel plate so as to have an H-shaped cross section. The joint arm 9 is composed of an extension portion of two flange portions of the assembled shaped steel, and the tip end portion of each joint arm 9 is T-shaped so as not to come off from the slit 8.
It has a V-shaped cross section.

In this embodiment, the main vertical hole 1 is first excavated, then the main wall core member 3 is built and the grout material 5 is filled. Similarly, after the sub pit 2 is excavated, the sub wall core member 4 is built and the grout material 5 is filled. The sub vertical holes 2 are formed by connecting three small diameter holes in a straight line. The grout material 5 is also provided in the longitudinal hollow portion formed between the steel plate for the short side of the box-shaped cross section of the main wall core member 1, the two hollow joints 10 and the web portion of the sub wall core member 4. It is filled. Composite cylinder 1 in the above embodiment
There is no equivalent to 4, and the composite column 13 is the sub-wall core member 4
Is directly connected by. Main wall core member 3 and sub wall core member 4
Is connected by the two sets of hollow joints 10 and joint arms 9, so that the joint strength is increased.

[0021]

According to the construction method of the present invention, the main wall core member 3 and the sub wall core member 4 are built in the main vertical hole 1 and the sub vertical hole 2 which are excavated in the ground 6, and the longitudinal direction of the side surface of the main wall core member. The hollow joint 10 is fitted with the joint arm 9 in the longitudinal direction on the side surface of the sub wall core member through the side surface slit 8 from the longitudinal direction, and the main wall core member 3, the sub wall core member 4, each hollow portion of the hollow joint 10, and the sub joint. The grout material 5 is provided in the hollow portion formed between the wall core member 3 and the main wall core member 1 or the hollow joint 10 and in the main pit 1 and the sub pit 2.
To form the side wall portion 12, and the side wall portion 1
Since the surrounding ground is prevented from collapsing by 2, the excavation of the inner ground of the side wall portion 12 and the placing of grout material can ensure the safety of the worker.

At the side wall of this underground tank, the hollow joint 1
0 and the joint wall 9 interconnect the main wall core member 3 and the sub wall core member 4 to form a chain-like skeleton, and the hardened layer of the grout material 5 wraps the skeleton to tightly bond and integrate them. Since it has a cylindrical composite structure, the side wall 12 withstands large earth pressure and groundwater pressure from the surrounding ground, and exerts great strength against bending moment and shearing force. According to this, a large-scale underground tank can be easily built even on soft ground.

In the construction method of the present invention, since the surrounding ground is prevented from collapsing by the side wall portion 12 which is built in advance, it is not necessary to previously improve the ground by injecting a chemical solution as in the conventional method, and chemical injection is possible. It can reduce the problem of groundwater pollution.

In the building method of the present invention, since the side wall portion 12 has a strong cylindrical structure due to the integration of the chain-like skeleton body and the grout material layer, the side wall portion 12 has an increased proof strength. An underground tank can be built even at a considerable depth.
Therefore, if the tank volume is kept constant, the tank length can be made as long as possible and the tank diameter can be made small.
By utilizing this deep underground area, the area occupied by the tank on the ground surface can be saved, the area of surrounding construction-related land can be reduced, and the land can be effectively used. Large volume underground tanks can be easily constructed without inviting traffic obstacles.

Further, the construction method of the present invention includes the excavation of the main vertical hole 1 and the sub vertical hole 2, the construction of the main wall core member 3 and the sub wall core member 4, the filling work of the grout material 5, the inner ground. Such as the excavator and the bottom plate portion 7 are carried out by a combination of relatively simple work processes,
Since laborious works such as earth retaining work, bar arranging work, and formwork work can be deleted, the construction period can be shortened compared to the conventional method.

When the main wall core member 3, the sub-wall core member 4, the hollow joint 10 and the joint arm 7 constituting the skeleton of the side wall 12 are made of steel and cement concrete is used as the grout material 5, these skeletons are used. Since the inner and outer surfaces are surrounded by an alkaline layer and oxidative corrosion of the skeleton is accurately prevented, it is not necessary to separately perform anticorrosion construction. When this underground tank is used as a heat storage tank, it is not necessary to separately carry out heat insulating work because the heat insulating effect inherent in the concrete layer provides the required heat insulating effect.

[Brief description of drawings]

FIG. 1 is a plan view of a completed state of an underground tank constructed by a building method according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a plan view of a stage where a main vertical hole is excavated in the ground in the building method.

[Fig. 4] In the construction method, a main pit is excavated in the ground, a main wall core member is built in the main pit, and a grout material is filled between the main wall core member and the hollow joint and the hole wall of the main pit. It is a top view of the stage which it did.

FIG. 5 is a plan view of the step of filling the grout material in the longitudinal hollow portion of the main wall core member in addition to the space between the main wall core member and the hollow joint and the main vertical wall in the building method. ..

FIG. 6 is a plan view of a stage in which a sub pit is partially overlapped with the main pit and excavated between the two main pits filled with grout material in the building method.

FIG. 7: Fitting the joint arm of the sub-wall core member built in the sub-vertical hole in the building method into the hollow joint of the main-wall core member to form a hollow joint and a hollow portion in the longitudinal direction of the sub-wall core member and the sub-wall core member. It is a top view of the stage which filled up the grout material in the vertical hole.

FIG. 8 is a plan view showing a completed state of the underground tank constructed by the construction method according to another embodiment of the present invention.

FIG. 9 is a plan view showing a completed state of an underground tank constructed by a construction method according to still another embodiment of the present invention.

[Explanation of symbols]

 1 Main Vertical Hole 2 Sub Vertical Hole 3 Main Wall Core Member 4 Sub Wall Core Member 5 Grout Material 6 Ground 7 Bottom Plate of Underground Tank 8 Hollow Joint Slit 9 Joint Arm on Side Wall Core Member Side 10 Main Wall Core Member Side Hollow joint 11 Hollow joint embolization cylinder 12 Side wall of underground tank 13 Synthetic column 14 Synthetic column

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location E03B 11/14 9125-2D

Claims (1)

[Claims] 1. A main wall core member in which a plurality of main vertical holes are excavated in the ground along the circumferential direction of an underground tank to be built, and hollow joints are provided on both side surfaces in a longitudinal direction to project the main wall core member. Built in,
A sub-wall core member with joint arms projecting in the longitudinal direction on both sides is built in the sub-hole excavated in the ground in the middle of the main pit, and the joint arm of the sub-wall core member is attached to the adjacent main wall core. The hollow joints of the members are fitted from the longitudinal direction through the slits in the longitudinal direction of the hollow joints, and the hollow portions in the longitudinal direction of the main wall core member and the hollow joint, and the hollow portions or the sub wall cores in the longitudinal direction of the sub-wall core member itself. A hollow part in the longitudinal direction formed between the member and the main wall core member or hollow joint, and a side wall part is constructed by filling the main pit and the sub pit with grout material, and the side wall part is embedded. A method of constructing an underground tank in which the inner ground of the side wall is excavated leaving the depth, and grout material is placed on the bottom of the excavation to construct the bottom.