JPH09235978A - Construction method of shaft by use of immersion block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method excellent in workability and economical efficiency and with less troubles like vibration, noise, slurry treatment, etc., by which a shaft can be constructed by use of relatively simple equipment even in a small space. SOLUTION: A shaft opening is excavated from the ground level down to a depth in which an immersion block 2 can stand for itself and a hanger frame base 3 is installed there. An excavating device 8 is erected through a rotary device 7 or the like. The excavating device 8 is rotated and advanced to a specified depth of the shaft 1 while injecting a solidifying agent like cement milk from the front end to agitate and mix the solidifying agent and the soil. After the excavating device 8 has been pulled out, cylindrical immersion blocks 2 are settled down in the slurry of soil in the excavated hole by making use of the own weight while connecting the blocks one by one. After completed settling of the immersion blocks 2, the solidified soil in the immersion blocks is excavated and discharged and base concrete 14 is placed on the bottom of the shaft 1.

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 a vertical shaft using a submerged block in the construction of a vertical shaft for a small diameter propulsion method, a vertical shaft for manholes and the like.

[0002]

2. Description of the Related Art Heretofore, in a manhole / shaft, a cylindrical precast concrete block joined in the depth direction has been used. In that case, the application and demand
Those having an inner diameter of 900 mm or less account for a considerable proportion.

As a conventional construction method, there is generally used a method of constructing a sheet pile for retaining a mountain, digging the installation position largely, and after installing the manhole block, backfilling the surroundings and pulling out the sheet pile.

However, in that case, the equipment for excavation becomes large and uneconomical, and it is often difficult to carry in the equipment for excavation in an area where buildings and the like are densely packed.

[0005] Further, when the sheet pile is pulled out after backfilling, there is also an influence of soil and the like adhering to the sheet pile, and the like.
The voids of that volume may cause consolidation settlement,
An H-section steel or the like for support is arranged at the bottom of the excavation, and a manhole is placed on the H-section steel. However, in this case, there is a problem that the settlement may adversely affect an adjacent building or the like. In addition, there is a problem of underground contamination with chemicals for ground improvement such as injection of chemicals.

On the other hand, as a construction suitable for a manhole-combined sinking pit having an inner diameter of about 2 to 3 m, a tubular sinking block by the inventor of the present application is joined while sequentially excavating the inside,
A construction method for digging is described in JP-A-6-117176.

[0007] Normally, however, it is necessary to provide a blade opening in the bottommost submerged block, which is a special product, which adds to the cost, and when the groundwater level is high, the water from the bottom of the excavation due to boiling etc. There is a problem that measures against the intrusion of Moreover, since it is difficult to use a commercially available cylindrical block for the general portion, the application conditions are limited in terms of cost performance and the like.

INDUSTRIAL APPLICABILITY The present invention is suitable for construction of a shaft with a small diameter, which is in great demand, can be constructed by a relatively simple facility even in a narrow place, and has excellent workability and economical efficiency with less problems such as vibration, noise and muddy water treatment. The purpose of the present invention is to provide a method for constructing a vertical shaft using a submerged block.

[0009]

The method for constructing a vertical shaft using the sinking block of the present invention is suitable for constructing a vertical shaft having a relatively small diameter as described above. A solidifying material is poured into and mixed with the earth and sand to form a slurry, which is excavated to a predetermined depth. Then, after pulling out the excavation device, while sequentially joining the cylindrical sunk blocks in the depth direction, by using the self-weight to deposit the sediment and the solidifying material from the pit into the slurry in the excavation hole After the completion of the digging, the shaft is constructed by excavating and removing the hardened soil in the sunk block again.

As the submerged block, a commercially available 1
A cylindrical precast concrete with an inner diameter of 900 mm for a person's hole can be inexpensively used, but the size, shape, and material are not necessarily limited thereto.

The solidifying material is generally cement milk or other cement-based material which does not easily cause problems such as underground pollution, and the settling block is settling by utilizing its own weight in a state of stirring and mixing with earth and sand to form a slurry. It is possible.

[0012] In addition, it is necessary to take a relatively long curing time in relation to the construction process, and it is easy to lay down the blocks for a period of 1-2 days when the installation of the laid blocks is completed for one vertical shaft. Formulate to maintain the condition.

As a stirring type excavating device, a stirring type generally equipped with a stirring blade at the tip of a rotating shaft and ejecting a solidifying material such as cement milk from the stirring blade portion through the shaft is also common. Various types are available.

After the required number of joined submerged blocks have been submerged to a predetermined depth, the submerged blocks are prevented from further sinking (for example, suspended and supported by a steel rod or the like also serving as a height adjusting member at the wellhead) and solidified. The soil mixed with the material is cured, and the inside of the sunk block is excavated and discharged again using the mini clam shell or auger.

It should be noted that the hydrophilic urethane agent is applied to the inner wall of the block before the deposition, and the dried block is submerged in the slurry, so that the hydrophilic urethane and water react and swell, so that the solidifying material is fixed to the inner wall. Can be easily eliminated without

Regarding the outer wall surface of the submerged block,
By hardening the soil mixed with the solidifying material, strength can be obtained without generating voids, and there is no fear of adverse effects such as ground subsidence.

According to claim 2 of the present application, when the ground at the bottom of the vertical shaft to which the above-mentioned construction method is applied is soft, a supporting force for the vertical shaft is secured, and intrusion of groundwater due to boiling etc. from the lower surface during vertical shaft construction is prevented. For the purpose of doing
From the bottom sunk block position to the required depth,
For example, about 300-1500 mm is improved to the strength that can secure the necessary supporting force by injecting the solidifying material and stirring with the earth and sand of the original ground, and installing the sunk block and placing the base concrete on the bottom of the shaft. It is a limited case.

In this way, while improving the soft ground at the bottom of the shaft, by installing the sunk block and placing the base concrete at the lower end of the shaft, reliable and reliable construction can be performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an embodiment of a construction method of the present invention, in which a precast concrete deposit having an inner diameter of about 900 to 1200 mm is constructed in the case of constructing a shaft for a small-diameter propulsion method passing under a road. It shows how the shaft 1 is constructed using the block 2. The following is an explanation along the construction procedure.

(1) Pavement removal and temporary excavation up to the self-sustaining depth Positioning marking is performed at the vertical shaft construction position, the pavement is removed, and the wellhead portion is excavated from the ground to a depth at which the lowest sunk block 2 can stand on its own.

(2) Installation of the hanger erection table (above, Fig. 1
(See (a)) The hanger erection table 3 is laid over the wellhead, and a lining plate support beam 4 for erection of a lining board that covers the wellhole at the time of construction suspension or curing is installed on the outside of the hanger erection platform 3.

FIG. 2 shows the positional relationship among the hanger erection table 3, the lining plate receiving beam 4, the lining plate 5 and the like at the wellhead, and hanging fittings 6 for lifting are provided at the four corners.

(3) Installation of rotating device and grout pump The rotating device 7 is installed on the hanger installation table 3, and the grout pump for feeding the solidifying material from the mixer is installed.

(4) Installation of excavation equipment, connection of grout hose The excavation equipment 8 provided with an excavation bit, a stirring blade, etc. at the tip is used with a relatively simple crane such as a rough terrain crane 9.
The grout hose 10 for injecting the solidifying material into the ground is connected through the hollow shaft of the excavator 8 which is built through the center of the rotating device 7.

(5) Solidified material mixed excavation (see FIG. 1 (b) above) The excavator 8 is rotated to inject a cement-based solidified material such as cement milk from the tip to a predetermined depth until the vertical shaft 1
Excavation and mixing of solidified material and earth and sand with stirring. It should be noted that the hydraulic motor 7a of the rotating device 7 can be given a required torque by the hydraulic pressure from the oil port of the rough terrain crane 9.

(6) Flooring In soft ground, etc., it is necessary to take into consideration the securing of bearing capacity and the infiltration of groundwater from the bottom of the excavation due to boiling, etc. It is spouted from the etc. and mixed with earth and sand by stirring to improve the ground.

(7) Lifting of concrete block After pulling up the excavation device 8, while suspending and supporting the submerged block 2 with the rough terrain crane 9, the solidified material and the earth and sand are removed while the upper submerged block 2 is being joined at the wellhead. The mixture is agitated and slowly sunk into the excavation hole that is in the form of a slurry.
It should be located within 1.

(8) Fixing with height-adjusting steel rod For adjusting the height of the submerged blocks 2 joined together, the number of submerged blocks 2 and the height at which the topmost submerged block 2 and the hanger erection platform 3 are connected at the wellhead The position can be fixed by adjusting with the adjusting steel rod 12. In addition, as for the uppermost part, a circular circular auxiliary soil retaining piece 13 made of steel as shown in FIG. 3 is used if necessary. The circular auxiliary fastener 13 can be fixed to the upper end of the submerged block 2 with a bolt or the like.

(9) Curing: Curing is carried out for about 1 to 3 days to cure the earth and sand mixed with the solidifying material.

(10) Vertical shaft excavation and residual soil treatment The vertical shaft 1 constituted by the submerged block 2 is excavated again to remove the earth and sand.

(11) Placing of base concrete (above, Fig. 1
(See (c)) The base concrete 14 is placed at the bottom of the shaft 1 to complete the construction of the shaft 1.

FIG. 4 shows another embodiment of the construction method of the present invention. The construction conditions and basic structure of the construction method are the same as those of the embodiment of FIG.

In this example, as the first step, the excavator 8
Drilling with a diameter of 300 mm (see Fig. 4 (a)) was carried out, and as a second step, the stirring blade 8a was attached to the excavator 8 and
A hole of 300 mm is drilled, and when the drilling device 8 is pulled up, the solidified material is jetted from the upper surface of the stirring blade 8a while stirring and mixing with the earth and sand (see FIG. 4 (b)).

The excavation device 8 can be supported by a rough terrain crane or a construction pole machine. In FIG. 4 (c), a swing stop 15 serving as a guide is installed at the wellhead portion, and the shaft of the excavator 8 is rotated to excavate, and the solidified material, water, and the like are fed into the shaft of the excavator 8 via the swivel 16. Can be supplied through.

FIG. 5 shows an outline of the shaft 1 as a whole concerning the treatment of the excavation bottom when the ground at the bottom of the shaft is soft.

In this example, as shown in the figure, at a depth of L (= 300 mm to 1500 mm) from the tip of the lowermost submerged block, the ground is improved by injecting the solidifying material and stirring and mixing with the soil of the original ground, It gives the necessary support to this part.

Positioning of the submerged block 2 with respect to the submerged depth is carried out by the height adjusting steel rod 12 of the wellhead, and after excavating the hardened earth and sand in the submerged block, the base concrete 14 is placed.

[0038]

[Effects of the Invention] Since the submerged block can be laid down by the minimum excavation which is slightly larger than the diameter of the vertical shaft, the construction can be carried out efficiently with simple equipment.

There is almost no effect on the surrounding ground such as consolidation settlement, and there is almost no noise and no vibration. In addition, there is no need to worry about soil contamination such as ground improvement due to injection of a chemical solution.

Very simple drilling and other equipment can be used, which is economical. It is also possible to work in narrow places.

In particular, when excavating a small-diameter vertical shaft,
There is no waste and quick and economical construction is possible.

In the case of the invention according to claim 2, even in the case of soft ground and high groundwater level, the intrusion of water from the bottom of the excavation is suppressed, efficient construction is possible, and the supporting force is secured, and excavation is ensured. No sludge is generated on the bottom, and a high-quality shaft can be constructed.

[Brief description of drawings]

1A to 1C are vertical sectional views showing a construction procedure in an embodiment of a construction method of the present invention.

FIG. 2 shows an outline of the structure of a wellhead equipped with a rotating device and a lining plate, (a) is a plan view and (b) is a vertical sectional view.

FIG. 3 shows an example of a circular auxiliary soil retention installed at the uppermost stage of the shaft, where (a) is a plan view and (b) is a vertical sectional view.

4A to 4C are vertical cross-sectional views showing a construction procedure in another embodiment of the construction method of the present invention.

FIG. 5 is a vertical cross-sectional view for explaining the processing of the excavation bottom.

[Explanation of symbols]

1 ... Vertical shaft, 2 ... Sinking block, 3 ... Hanger installation stand, 4
... lining plate receiving beam, 5 ... lining plate, 6 ... hanging metal fitting, 7 ... rotating device, 7a ... hydraulic motor, 8 ... excavating device, 9 ... rough terrain crane, 10 ... grout hose, 11 ... tip processing unit, 1
2 ... Height-adjusting steel rod, 13 ... Circular auxiliary soil retaining, 14 ... Base concrete, 15 ... Swing stop, 16 ... Swivel

Claims (2)

[Claims] 1. A vertical installation position is excavated to a predetermined depth by pouring and mixing a solidifying material into the earth and sand of an original ground by an excavating device to form a slurry, and after pulling out the excavating device, a cylindrical submerged block is sequentially deepened. It is characterized in that the earth and sand and the solidifying material are sunk into the slurry excavation hole from the pit using its own weight while joining in the vertical direction, and after the completion of the digging, the hardened earth and sand in the sunk block is excavated and removed. A method of constructing a vertical shaft using a submerged block. 2. When the ground at the bottom of the shaft is soft,
From the bottom sunk block position to the required depth, the ground is improved to the strength that can secure the necessary supporting force by injecting the solidifying material and stirring with the soil of the original ground, and installing the sunk block and the bottom of the shaft. The method for constructing a vertical shaft using a sunk block according to claim 1, wherein base concrete is placed.