JP2821933B2 - Underground structure construction method - Google Patents

Description

The present invention relates to a method of constructing an underground structure such as an underground structure or a structure having an above-ground building thereon, particularly a structure to be constructed. Underwater excavation underwater while balancing its own weight and the pressure of the water filled into the bottom thereof.

"Conventional technologies and problems to be solved by the invention" Conventionally, as a method of constructing a structure underground, there are generally known methods such as a digging method using a stake, a pneumatic caisson or an open caisson. ing.

However, in the open-cutting method using the shoring support, since the load is applied to the shoring due to groundwater pressure and earth pressure outside the shoring, the shoring must be strengthened. There was a problem that the construction cost related to the wall was increased.

In the construction method using a pneumatic caisson, safety issues for workers due to pneumatic work, instability of construction due to the imbalanced load acting on the structure due to subsidence, inability to settle due to peripheral friction, high excavation precision There are various problems in the construction of the underground structure, such as the excessive design of the lower floor plate as a working room slab determined by the requirements of the construction and the conditions at the time of construction.

In addition, the open caisson method has problems that it is difficult to control the attitude and position during excavation, and that deep excavation cannot be expected due to problems such as groundwater pressure and earth pressure.

Therefore, the applicants used an underground structure construction method in which the lower part of a structure to be built by storing water inside the retaining wall was floated on the water inside the retaining wall, and the ground below the structure was Is excavated underwater by an excavator, and the upper part of the structure is sequentially raised on the lower part of the structure in parallel with the progress of the excavation, and the weight of the structure or the load added thereto is balanced while the structure is (Japanese Patent Application No. 1-132453).

However, although the above-mentioned construction method is simpler than the open-cutting method using the shoring support, the shoring wall is required, and thus there is a problem that the construction period and the construction cost are required.

"Means for Solving the Problems" In order to solve the above-mentioned conventional problems, the present invention provides a structure in which an excavation chamber with an open bottom is provided at the bottom, and a communication opening is provided on the floor above the excavation chamber. The lower part is constructed in advance on the ground, digging the ground below the bottom, sinking it to a predetermined position, installing an underwater automatic excavator in the excavation room, connecting to the communication opening, and excavating from the cylinder rising up After filling the room with water,
The ground under the excavation room is excavated underwater by an underwater automatic excavator, and the lower part of the structure is laid down while balancing its weight and the pressure of the water in the digging room. An underground structure in which the upper part of the structure is built in a series, and the structure is laid down at a predetermined position while digging underwater with the automatic underwater digger in the same way, and concrete is poured into the digging room and the communication opening after the digging is completed It proposes a construction method for objects.

"Action" By using the outer wall of the structure to be built also as the retaining wall, construction of the retaining wall is omitted, and water is injected and filled into the space surrounded by the lower part of the structure and the lower ground. Underwater excavation by an automatic underwater excavator makes it possible to perform excavation safely and easily without pneumatic work.In addition, the weight of this structure and the pressure of water filled in the bottom, and the connection between this structure and the ground By balancing the frictional force acting therebetween, the structure can be reliably and continuously settled at a predetermined position while being concurrently excavated.

"Example" Hereinafter, the present invention will be described with reference to an example shown in the drawings. As shown in FIG. 1, a structure lower part 1 which is a lower part of a structure to be constructed on a construction planning ground is constructed.

The lower part 1 of the structure has an outer wall 1a having a sharp edge at its lower end, a digging chamber 1b having a bottom opening at the bottom, and a communication opening 1d provided on a floor 1c on the digging chamber 1b. It is configured as a concrete structure, and a cylindrical body 2 is connected to the communication opening 1d and is raised upward.

Next, as shown in FIG. 2, the lower part of the structure 1 is laid down while excavating the ground below the lower part 1 of the structure 1 to near the groundwater level with human power or an excavator.

Then, as shown in FIG.
In 1b, an automatic underwater excavator 3 such as an unmanned sand pump excavator with a cutter is assembled and installed on the bottom of the floor 1c. Water is injected and filled into 1b to apply a required head pressure to the bottom of the lower part 1 of the structure.

The underwater automatic excavator 3 that travels on the bottom ground of the excavation room 3 can also be used.

In this state, the ground under the excavation room 1b is excavated underwater by the automatic underwater excavator 3 to determine the weight of the lower portion 1 of the structure (including its own weight and the load added thereto) and the pressure of the water adjusted and filled at the bottom, and The lower part 1 of the structure is smoothly laid down while appropriately balancing the frictional force acting between the lower part 1 of the structure and the ground.

Thereafter, as shown in FIG. 4, the excavation and subsidence are carried out in the same manner as described above while simultaneously constructing the upper parts 5, 5 ',. The required underground structures are repeatedly laid down and installed.

Note that the mud excavated at this time is discharged to the outside by the discharge pipe 4.

After the submersion is completed in this manner, as shown in FIG. 5, the water in the excavation room 1b is drained, the automatic underwater excavator 3 is dismantled and removed, and the concrete 6 is placed in the excavation room 1b and the communication opening 1d.
And if necessary, a ground consolidation material is injected around the structure 1 to complete the construction.

It is needless to say that the structure 1 constructed according to the present invention can be constructed as a structure in which an above-ground building is continuously constructed underground in FIG.

[Effect of the Invention] As described above, according to the present invention, the structure to be built is used as the outer wall itself as a retaining wall, and is directly laid down to the required position without performing digging by retaining the pier. Eliminating the shoring work cost makes it possible to greatly reduce the entire work cost.

In addition, water is filled in the excavation room at the bottom of the structure, and the ground below is excavated underwater by an automatic underwater excavator, so that the weight of the structure and water pressure, and the frictional force acting between the structure and the ground Can be settled stably and safely at a predetermined position while appropriately balancing the above, and at the same time as the excavation progresses, the upper part of the structure is successively erected on the lower part of the structure while being erected. And work costs can be reduced.

[Brief description of the drawings]

1 to 5 are longitudinal side views sequentially showing the construction steps of the present invention. 1 ... lower part of structure, 1a ... outer wall, 1b ... excavation room, 1c ... floor, 1d ... communication opening, 2 ... cylinder, 3 ... automatic underwater excavator, 4 ... mud pipe , 5,5 ': Upper part of the structure, 6: Middle embedded concrete.

Claims (1)

(57) [Claims] An excavation chamber with an open bottom is provided at the bottom, and a lower portion of a structure having a communication opening in the floor above the excavation chamber is previously constructed on the ground, and a predetermined area is excavated while excavating the ground below the bottom. Submerged in the excavation room, an underwater automatic excavator is installed in the excavation room, and water is filled into the excavation room from a cylindrical body which is connected to the communication opening and rises upward. Underwater excavation is performed by an excavator, and the lower part of the structure is laid down while balancing the weight of the lower part and the pressure of the water in the digging chamber, and the upper part of the structure is sequentially built on the lower part of the structure in parallel with the progress of the laying. The underground structure is characterized in that the structure is submerged in a predetermined position while being excavated in the same manner by an underwater automatic excavator, and concrete is poured into the excavation chamber and the communication opening after the completion of the submersion. Construction method.