JP3430376B2 - How to build an underground skeleton - Google Patents

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 structure.

[0002]

2. Description of the Related Art In recent years, building structures such as buildings and civil engineering structures have been increasing in size and depth in plan view. For such construction of large underground structures, safe, efficient and economical construction methods are required. When constructing a large underground structure, generally, a continuous underground wall or a mountain retaining wall such as a steel pipe sheet pile is built around the planned structure, and a mountain retaining structure is installed inside to excavate. The method of repeating is common.

[0003]

However, the conventional method has the following problems. <A> Complexity of assembling the mountain shoring support due to excavation, construction work in a narrow space between the mountain shoring supports arranged in multiple stages,
The type of work is complicated, such as the dismantling work of the supporting work, and the risk is high. <B> Since the type of work is complicated, the number of processes is increased and the work cost is increased.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of constructing an underground skeleton by an open caisson, which simplifies working steps and has high construction accuracy.

[0005]

Means for Solving the Problems The present invention provides a method of constructing an underground skeleton by an open caisson, wherein an impermeable wall is provided to the outer periphery of a range where the underground skeleton is constructed to a depth deeper than the construction depth of the underground skeleton , Ground below the open caisson
Anchors are provided near the blades of multiple open caissons.
Place the jack, excavate in the air, and attach the earth anchor.
Pull it with a jack and use the pulling reaction force to
The caisson is simultaneously laid down and the open caisson is connected.
It is a method of constructing an underground skeleton, which is characterized by continuing and constructing an integral underground skeleton.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. <B> Underground building When building a building under the ground, a water impermeable wall 2 such as an underground continuous wall is built around the planned construction site of the building. In order to lower the water level in the inner area of the impermeable wall 2, the deep well (pumping well) 3 is dug. While lowering the groundwater in the inner area of the impermeable wall 2, the ground excavation is carried out and the open caisson 1 is sunk to construct an underground skeleton. When the open caisson 1 sinks, a center hole jack 41 is arranged near the blade opening 11, and the pulling reaction force of the ground anchor 4 can be used to perform it safely and accurately. When constructing a large skeleton, a plurality of open caissons 1 are simultaneously sunk and joined to each other.

<B> Impermeable Wall The impermeable wall 2 is a well-known continuous underground wall, etc., which is constructed underground to prevent groundwater from flowing into the construction site of the open caisson 1. By making the depth of the impermeable wall 2 deeper than the depth at which the open caisson 1 is finally submerged, the influence of groundwater in the subsidence work is removed and the water level fluctuation of the groundwater outside the impermeable wall 2 is eliminated. Can be held down. Deep wells (pumping wells) 3 are provided at a plurality of locations inside the impermeable wall 2. The deep well 3 can pump up groundwater inside the impermeable wall 2 to lower the groundwater.

<C> Open caisson The open caisson 1 is determined according to the underground skeleton, such as one having an outer frame having a rectangular shape, a circular shape, or one having a partition inside. The open caisson 1 has a blade opening 11 at a lower portion thereof, and a horizontal portion on which the center hole jack 41 can be placed is provided near the blade opening 11. Open caisson 1 is impermeable wall 2
It is sunk by aerial excavation in the inner area of and is built as an underground structure. When constructing a large underground structure, multiple open caisson 1 are simultaneously sunk by aerial excavation,
After the completion of the construction, the caisson will be connected and an integrated underground structure will be built. When the open caisson 1 sinks, the deep well 3 draws underground water to adjust the water level.

<D> Earth Anchor An earth anchor 4 extending below the open caisson 1 is provided. By arranging the center hole jack 41 near the blade opening 11 of the open caisson 1, pulling the ground anchor 4 upward, and applying a reaction force to the open caisson 1, it is possible to control the settlement of the open caisson 1. Since the center hole jack 41 is arranged below the open caisson 1, the settlement can be accurately controlled.

<E> Ground improvement When constructing an open caisson skeleton body on the ground, if the installation ground of the open caisson 1 cannot support the weight of the open caisson skeleton body, the ground is improved to make it a weight-bearing ground.

<F> Foundation pile If the support layer below the underground structure is deep, strike the foundation pile 6
The foundation pile 6 supports the ground structure.

<G> When the bottom slab concrete open caisson 1 is sunk at a depth reaching the support layer, the open caisson skeleton body is replaced with the bottom slab concrete 7
Hold it directly on the support layer. When supported by the foundation pile 6, the bottom slab concrete 7 is the concrete 7 that rigidly connects the foundation pile 6 and the open caisson 1. The slab concrete 7 is placed below the open caisson 1.

<H> Joint between open caissons A plurality of open caissons 1 are simultaneously sunk, and after the completion of the digging, the ground between the open caisson 1 is removed and a joint 5 is formed to build a large underground structure. To do.

The process of staking the open caisson will be described below. <A> Construction of impermeable wall An impermeable wall 2 is provided by a continuous underground wall on the outer periphery of the area where the underground structure is built. The depth of the impermeable wall 2 is set to a depth below the depth of the underground structure to shut off groundwater. The deep well 3 is provided inside the impermeable wall 2 up to near the lower end of the impermeable wall 2 to remove the groundwater inside and to adjust the water level. If the ground is poor and the open caisson structure cannot be supported, ground improvement will be performed. The earth anchor 4 is provided deeper than the sunk position of the open caisson 1.

<B> Sinking of open caisson A center hole jack 41 is fixed near the blade opening 11 of the open caisson 1, and a tension member for the earth anchor 4 is attached. The air is excavated, the center hole jack 41 is operated, and the open caisson 1 is sunk by its reaction force.
At this time, the deep well 3 is used to lower and adjust the groundwater level near the open caisson blade 11. When constructing a large underground structure, multiple open caisson 1 are sunk at the same time.

<C> Construction of underground skeleton When the open caisson 1 is sunk at a depth reaching the support layer, a bottom slab concrete 7 is placed below the open caisson to fix the open caisson 1 to the support layer. When the support layer is deep, the support pile is hit and the support pile and the open caisson 1 are rigidly connected with the bottom slab concrete 7. When a plurality of open caissons 1 are sunk, the ground between the open caissons is excavated and the open caisson 1 is connected.

[0017]

According to the present invention, the following effects can be obtained. <A> Since excavation is performed in the air, excavation efficiency can be improved. <B> Since the excavation under the blade can be freely performed, the sinking control such as the inclination correction of the skeleton can be freely performed, and the sinking accuracy can be improved. <C> Since the simultaneously-deposited skeletons can be joined in the air, the construction efficiency and construction accuracy are high, and high quality, rapid construction, and low cost can be obtained. <D> As the open caisson sinks, the water level of the groundwater gradually decreases in the vicinity of the cutting edge, so even if the water impermeability of the water-impervious wall 2 is low, it has little effect on the lowering of the groundwater level in the vicinity.

[Brief description of drawings]

FIG. 1 Diagram showing settlement of open caisson

[Figure 2] Plan view of settlement of open caisson

FIG. 3 is a view showing the inside of the impermeable wall before the open caisson is sunk.

FIG. 4 is a diagram showing the start of settlement of an open caisson.

[Figure 5] Open caisson sinking diagram

[Explanation of symbols]

1. Open caisson 2 ... Impermeable wall 3 ... Deepwell 4 ... Earth anchor

Claims (3)

(57) [Claims] 1. A method of constructing an underground skeleton by an open caisson, wherein an impermeable wall is provided to the outer periphery of a range where the underground skeleton is built to a depth deeper than the construction depth of the underground skeleton, and earth anchors are provided below the plurality of open caisson. Install, place jacks near the blade openings of multiple open caissons, excavate in the air, pull the earth anchor with the jacks, and simultaneously sink multiple open caissons by pulling reaction force, A method of constructing an underground skeleton, which is characterized by connecting and building an integral underground skeleton. 2. A method of constructing an underground skeleton by an open caisson, wherein an impermeable wall is provided to the outer periphery of the range where the underground skeleton is constructed to a depth below the construction depth of the underground skeleton, and the interior surrounded by the impermeable wall. A deep well is installed on the ground, ground anchors are installed below the open caissons, jacks are placed near the blades of the open caisson, and the groundwater level inside the impermeable wall is lowered while drilling in the air. Then, pull the earth anchor with the jack, sunk multiple open caisson at the same time by pulling reaction force, connect multiple open caissons, and reinforced the lower part of the open caisson with bottom slab concrete to build an integrated underground skeleton. A method of constructing an underground skeleton, characterized by: 3. A method of constructing an underground skeleton by an open caisson, wherein an impermeable wall is provided at an outer periphery of a range where the underground skeleton is constructed to a depth deeper than a construction depth of the underground skeleton, and an interior surrounded by the impermeable wall. A deep well is installed in the ground, the ground improvement material is injected into the interior surrounded by the impermeable wall to improve the ground, and ground anchors are installed below the open caissons, near the cutting edges of the open caissons. Place a jack, excavate in the air while lowering the groundwater level inside the impermeable wall, pull the earth anchor with the jack, and simultaneously sunk multiple open caissons by pulling reaction force, and open multiple A method of constructing an underground skeleton, characterized by connecting the caisson, reinforcing the lower part of the open caisson with bottom slab concrete, and constructing an integrated underground skeleton.