JPS5931318A - Caisson work - Google Patents

Abstract

PURPOSE:To enhance the operational efficiency of caisson work by a method in which the ground is excavated by utilizing water gathered in the pit excavated side, a caisson is settled, underwater concrete is placed onto the bottom of the trench and hardened until the strength of the concrete is developed, and then the water in the caisson is discharged. CONSTITUTION:In excavating the ground by utilizing water gathered on the pit excavated side, a structural base 10, an ascending pier 11, and a hanging scaffold 12 are assembled. They are attached with an excavator 14 and a separator 15, together with a water supply or discharge tank (not illustrated). An earth anchor 16 is fixed to the structural base 10 to obtain the reaction of a jack 13, the excavation of the central part and the suction of water are started, and the jack 13 is actuated by jetting water from the tip of the blade. The settling of caisson is repeated to a given depth gradually, and after the completion of the settling, underwater concrete 21 is placed on the bottom of the excavated trench. When the load of the superstructure of the caisson is increased and balanced with the buoyancy, water is drained.

Description

[Detailed Description of the Invention] This invention relates to a method of constructing a subcase to be the foundation part of a structure or the lower room of a Jlh on the ground and sequentially sinking it. The aim is to shorten the time and reduce construction costs.

When performing root cutting3 and underground structure work in ground with a high groundwater level, conventional temporary construction such as retaining walls, shedding, drainage facilities, fjing stands, etc. will put pressure on the construction period and Tl cost. There is. J13 under construction is j+I! ! The reason why it is considerably more expensive than the 1-year project is the expense involved in this temporary construction.

Analyzing these from a technical perspective, the current +lll
Since each work in the substructure work 1 F is based on the premise of dry work, the fact that the root cutting side is kept dry has emerged as an important cause.

In contrast, the construction method of this invention improves the conventional submerged box construction method,
Water, which has traditionally been removed using various methods in the construction of underground structures, is now actively used for excavation and fixation of external forces, and is particularly suitable for ground with a high groundwater level. .

In other words, in the submerged box method, water may not be drained from the root cutting side, but water may be injected if the ground lacks groundwater. The water will be used for excavation. Furthermore, after the submergence has been completed, underwater concrete is placed at the bottom of the excavation, and after this underwater concrete has developed its strength, the water inside the submerged case is drained and underground structure work can proceed, which saves labor in root cutting work. , it is possible to improve workability and reduce construction costs! The following procedures and construction methods are used for filtered materials.

(a) Store water on the side of the root cut.

(b) Use that water to excavate.

(C) During excavation, excavation water is circulated and used.

(d) Building walls, underground beams, and columns in sequence on the ground;
I'm going to sink it.

(e) The face piece can be sunk as necessary (if necessary, by applying a water jet with the cutting edge or by applying a load using a gantry, etc. as a reaction force).

(f) After settling the excavation, create a bottom cover with underwater concrete, etc. at the bottom of the excavation.

(g) After the underwater concrete has developed its strength, it is fixed with earth anchors as required.

(h) Contact with underwater concrete as necessary.
x In order to apply grout between the ground for ground improvement or water stoppage, set the grout piping inside the box.

It is possible to separate Goni sand and water outside the building by using the system to circulate only the water.

Next, an example of the submerged box construction method of this invention is shown in Figure 1~
This will be explained based on FIG. 11.

■ After removing underground objects and leveling the site.

Carry out photographing, inking, and setting benchmarks (see Figure 1) 0 ■ Excavate the cutting edge (stop at about 100 to 200 W above the groundwater level), and fill the excavated soil into part a of the underground beam construction. Perform ground leveling. After that, pour concrete 1 for the cutting edge, underground beams, and construction parts and mark them out (see Figure 2).
.

■ Assemble the formwork 2, scaffolding 3, and reinforcing bars 4, attach the cutting edge hardware 5, jet vibro, steel frame anchor 7, etc., and pour concrete (see Figure 6).

(Excellent) To install the water stop plate 8, remove the laitance and cure the concrete 9. After that, the formwork 2 is dismantled and the outer periphery is backfilled (see Figure 4).

In addition, if earth anchors are installed and the weight of the structure is insufficient, this will be used as a reaction force to sink the structure or to adjust the level of the structure.

■ 11q platform 10, climbing pier 11'J6 and hanging scaffold 12
, install the jack 15, excavator 141, separator 15, etc., and set the water supply and drainage tank. An earth anchor 16 is fixed to the gantry 10 to take the reaction force of the jack 13.

Then, excavation 2 in the center area starts water absorption, a water jet is injected from the tip of the sword, and the jack 13 is started (see Figure 5). 0. Once the stone has been submerged to a predetermined depth, the submergence is temporarily stopped. , the earth anchor 16 is released, the gantry 10 is jacked up, and the ground anchor 16 is fixed again.

■ Arrange formwork 17, reinforcing bars 18, etc., and construct the underground structure (6th inspection M). In addition, 19 in the figure is a pipe support. Also, the slab will be applied later. Furthermore, in cases where the scale is relatively small, an underground framework may be constructed using precast boards.

Excavation and water absorption are started again, the water jet is injected, and the jack 13 is started (see Figure 7).

Thereafter, the sinking is repeated successively to a predetermined depth, and when the sinking is completed, the excavator 14, separator 15, etc. are removed.

■ Place underwater concrete 21 at the bottom of the excavation.

At this time, the water level is secured from the water suction pipe 171C. Further, the head of the earth anchor 16 is fixed to the underground framework. Anchors driven into the structure are temporarily anchored in underwater concrete. Grout around the cutting edge using a jet vibro (see Figure 8).

Q) Assemble the slab formwork 22 and reinforcing bars (see Figure 9). Note that FIG. 9 shows a cross section between the beams, and a deck plate is used as the slab formwork 22, which is suspended from the gantry 10. Place slab concrete 25,
After curing, the gantry 10 is dismantled and transported.

■ Assemble the external scaffolding 24 and fabricate the upper frame with foil (see Figure 10).

■ Drain water when the load on the upper structure increases and the buoyancy is balanced. After cleaning, tidying up, and removing laitance from the underwater concrete 21, underground slab reinforcements 25 are assembled and slab concrete is poured (see Fig. 11). Finally, finishing is performed and the underground construction is completed. This invention has the above configuration and has the following advantages and features.

(1) Temporary construction materials, especially disposable temporary construction materials, are scarce.

(2) Since dry work is not a prerequisite, all-weather construction is possible regardless of the weather.

(3) Since there is no pumping work (pumping up groundwater), there is less impact on the surrounding ground, which is advantageous for groundwater problems.

By using the cutting edge shown in Figure 12, it is possible to prevent surrounding ground subsidence due to pulling.

(4) Similarly, the external force acting on the excavation slope can be reduced.

(C.) It is possible to significantly reduce the labor force, and labor accidents are also reduced. Most of the work will be done above ground, creating a poor construction environment.
Workers are never lowered by one floor.

(6) Since there is less temporary construction work, etc., construction time is shortened and underground construction costs can be significantly reduced.

(7) When using a suction hole excavator, there is no upper or lower part of the JJil excavator, so the work efficiency does not decrease as the JJil excavation depth increases.

[Brief explanation of drawings]

FIGS. 1 to 11 are longitudinal cross-sectional views showing the working procedure in an embodiment of the present invention. 1. Discarded concrete, 2. Formwork, 3. Scaffolding. 4...Reinforcement bar, 5...Blade edge hardware, 6...Jet pipe, 7...Anchor for steel frame, 8...Water stop plate, 9...Concrete, 10...1flI stand, 11...Climbing pier, 12
・・Hanging scaffold, 13・・Jacket, 14・・Excavator, 15
・・Min PJIE machine, 16・・Earth anchor, 17・・
Water absorption pipe, 18Φ, formwork, 19...reinforcement, 20...pipe the boat, 21...underwater concrete 1, 22...
Slab formwork, 23...Slab concrete!・、24・・
External scaffolding, 25... Underground slab reinforcement. Figure 8, Figure 9 [4 Figure 10, Figure 111', 4

Claims (1)

[Claims] (1) A method of construction in which the canals are placed one after another on the ground, the ground on the side of the root cutting at the bottom of the canal is excavated one after another, and the canals are sunk, and water is collected on the side of the root cutting and the water is used. After the submersible has been sunk, underwater concrete is placed at the bottom of the excavation, and this underwater concrete provides strength.
A sub-box construction method characterized by draining the water inside the sub-box.