JPS5945071B2 - Foundation excavation method for steel towers, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for excavating foundations for steel towers, etc., which aims to enable efficient and easy foundation excavation when constructing steel towers, etc. in mountainous areas.

Conventional construction methods involve a large proportion of manual labor, and mechanization in this field has lagged behind.

The reason for this is: ■ Because it is located in a mountainous area, mechanical scaffolding is poor, and in order to use heavy machinery suitable for excavation work, it is necessary to downsize and use heavy equipment.
There are some difficult aspects such as the need to reduce weight and make assembly easier.

■ In some cases, it is impossible to transport these equipment by land, so they are often transported by air.

■ The number of work days is limited.

■ It is necessary to develop inexpensive mechanical devices that are commensurate with machine losses.

There are many problems.

Therefore, conventionally, topsoil excavation (clay, silt) was carried out using a small shovel, and when the shovel arm could no longer reach, a person entered the hole and manually dug and scraped, and if bedrock came out, a small shovel was used. Currently, manual excavation is carried out using concrete breakers.

In recent years, with the aim of reducing power transmission costs and saving energy, ultra-high voltage transmission of hydroelectric power generation has been considered, and the need to construct numerous steel tower foundations in mountains has increased, and the present invention provides a method for efficiently excavating the foundations of steel towers, etc. We aim to provide the following.

The present invention will be described below based on drawings showing an example of implementation.

First, the construction order will be explained based on FIGS. 1 to 20.

First, as shown in Figure 1, the slope 1 is cleared by cutting down vegetation, etc.
level the ground.

Next, as shown in Figure 2, the area required for foundation excavation is cut out from the slope by hand or with a small power shovel.

The remaining soil is stopped at shelf 2 to effectively create level ground 3.

On this flat ground 3, as shown in Figure 3, there is a foundation 4 for a gantry crane.
construction.

Next, a gantry crane 5 is installed on this foundation 4 as shown in FIGS. 4 and 5.

The portal crane 5 is small and has a structure that is easy to disassemble and assemble, and has a hoist 7 for a grab bucket 6 and a work hoist 8.

The gantry crane 5 is installed using a power shovel or with the help of another crane.

Next, as shown in FIGS. 6 and 7, a guide pipe positioning device 9 is attached to the portal crane 5.

In this case, the work hoist 8 is used to position the guide pipe positioning device 9 on the leg member 10 of the portal crane 5 for mounting the excavator so that the center of the excavator can be easily positioned at the location of the planned drilling hole. Fix it.

Next, as shown in FIGS. 8 and 9, the excavator 11 is assembled in the guide pipe positioning device 9 using the working hoist 8.

Thereafter, the excavator 11 starts excavating as shown in FIG.

Since the topsoil has a lot of clay and silt, the topsoil is excavated by operating the excavation and raking packet 12.

Since the excavation scraping packet 12 is attached to a swivel table 14 driven by a hydraulic motor 13, the excavation machine 1
The inside of the skin plate 15 of 1 can be excavated.

Excavated earth and sand are carried out of the excavator 11 by a grab bucket 6 and are discharged via a hopper 16 and a conveyor 17.

18 is a breaker provided in the auxiliary machine 11.

As the excavation progresses, the excavator 11 descends into the ground as shown in FIG. 11.

Here, the guide pipe 19 is connected to the excavator 11 according to the excavation depth.
The guide pipe fixing device 20 and guide pipe vertical movement device 21 are installed at the gate in order to detect bending in the excavation hole at an early stage, and to prevent insufficient descending force into the excavation hole and free fall of the excavator. It is provided inside the model crane 5.

In order to prevent the wall of the excavation hole from collapsing, the liner plate 22 is assembled inside the excavation hole, and the gap between the liner plate 22 and the excavation hole is injected with grout using excavated earth and sand to close the gap. .

In this case, the earth and sand may be mixed with water and pumped using a mono-pump or the like, or cement mortar may be injected.

As the excavation progresses and the hole becomes deeper, foundation supporting rock will emerge.

In this case, the excavation and scraping packet 12 cannot be used for sandstone work, and the breaker 18 and drifter 23 are used in combination to perform the sandstone work.

Therefore, as shown in FIG. 12, first, a large number of holes 24 are bored in the hole bottom, side wall, etc. using a drifter 23.

If the breaker 18 is used to strike the middle part of the holes 24 and 24, it will be in the same state as making many cracks in the rock, so the rock can easily be turned into sandstone.

If the efficiency cannot be improved by drilling with the drifter 23 or sandstone with the breaker 18 as described above, fill the hole 24 made by the drifter 23 with blasting material 25 such as dynamite as shown in FIG. 13 to crack the rock. or by blowing away the rock by blasting.

At this time, the guide pipe fixing device 20 and the guide pipe vertical movement device 21 separate the excavator 11 from the skin plate 15 and pull it up to prevent damage to the excavator 11 during blasting.

When the target excavation diameter reaches the excavation depth, the excavator 11 is lowered again to widen the bottom of the excavation hole 26, as shown in FIG.

The excavation work of the well-formed excavation hole 26 is now completed, and as shown in FIG. etc., and lift them to the ground using a work hoist 8.

Also, as shown in FIG. 16, the skin plate 15
The main body of the excavator 11 is also lifted to the ground by the work hoist 8 so as to remain inside the excavator 6.

Thereafter, as shown in FIG. 17, the skin plate 15 is disassembled and lifted to the ground by the working hoist 8.

In this case, since there is rock at the bottom of the excavated hole 26, the hole wall does not collapse even if the skin plate 15 is disassembled.

However, if collapse does occur, skin plate 1
5 is sometimes used as part of the shoring material and embedded.

Next, as shown in FIG.
Assemble.

After that, as shown in FIG. 19, the reinforcing bars 27 are fixed, and the reinforcing bars 2
When the fixing of the steel tower member 28 to 7 is completed, the excavated hole 26
Mortar 29 is injected and placed inside.

As the amount of mortar 29 increases, liner plate 2
2 will be disassembled and recovered on the ground.

Finally, as shown in Fig. 20, mortar 29 is sufficiently poured to restore the topsoil to its original condition and the tower foundation is completed.

Next, the excavator 11 will be described in detail based on FIGS. 21 to 23.

The skin plate 15 of the excavator 11 has a flange on its end face, so that it can be easily disassembled and assembled.

In the embodiment shown in the drawings, it can be divided into four in the circumferential direction.

The skin plate 15 has the excavation scraping packet 12, breaker 18, drifter 23, etc. inside the skin plate 15, and is equipped with a cylinder device that swings and moves these up and down.

If the excavation mechanism vertical movement hydraulic cylinder device 30 is at the upper limit and the excavation scraping packet vertical movement hydraulic cylinder device 31 is at the upper limit, the excavation scraping packet 12 is at position A in FIG.

In order to excavate at this position, the hydraulic cylinder device 31 may be operated to lower the excavation scraping packet 12 to the position B in FIG. 21.

By operating the hydraulic cylinder devices 32 and 33 for swinging and ejecting the excavation raking packet, earth and sand can be excavated and the earth and sand can be raked into the center of the excavator 11.

At this time, the excavation scraping packet 12 is
', B→B', CTC', etc. as appropriate.

At the position C' in FIG. 21, the tip of the excavation scraping packet 12 protrudes outward from the outer periphery of the skin plate 15, and this shows the state when bottom widening is performed at the bottom of the excavation hole 26.

At this time, it is considered that the ground will not collapse even if the skin plate 15 is disassembled, so the skin plate 15 is appropriately disassembled in consideration of workability to facilitate the bottom expansion work.

In order to perform the excavation and raking work around the tip of the skin plate 15, the swivel table 14 is configured to be able to swivel around a vertical axis by mechanisms such as the hydraulic motor 13 and the swivel bearing 34.

Further, the breaker 18 and the drifter 23 are provided with hydraulic cylinder devices 35, 36 for swinging and hydraulic cylinder devices 37 for vertical movement.
This makes it possible to swing and move up and down, and it is also possible to turn around the vertical axis in the range a++a' in FIG. 21 by means of a turning hydraulic motor 38.

It can also be turned sideways as shown in Figure 21, so
The chisel (bit) of the breaker 18 can be applied to the rock fracture surface in any direction.

The breaker 18 is equipped with a hydraulic cylinder device 3 for ejection.
9 are provided on both sides, and Fig. 21 a, b, c and a/
.

Feeds can be applied to the breaker 18 like b', cl or d/, 3/.

On the other hand, the drifter 23 is attached to the side of the breaker 18 via a bracket, and can assist the breaker 18 in sandstone work.

By the way, during the blasting described in FIG. 13, if the connecting pin 40 between the skin plate 15 side shown in FIG. 21 and the excavation mechanism vertical movement hydraulic cylinder device 30 is pulled out, the excavation mechanism and the skin plate 15 are separated. The guide pipe 19 can be pulled up by the guide pipe vertical movement device 21 to prevent damage to the excavation mechanism during blasting.

51 is a hydraulic unit.

Next, the guide pipe positioning device 9 will be described in detail based on FIGS. 24 to 27.

This guide pipe positioning device 9 is connected to the gantry crane 5.
The guide pipe fixing device 20 and the guide pipe vertical movement device 21 are comprised of a positioning fixture 41 that can be attached using the leg material 10 of the guide pipe fixing device 20 and the guide pipe vertical movement device 21.

The positioning fixture 41 is the leg member 10 of the portal crane 5.
The height is adjusted using the height adjustment screw 42.

A positioning bar 43 is attached to this positioning fixture 41 so that it is about 10 to 20 mm thicker than the external dimensions of the excavator 11.

In this state, the excavator 11 is assembled as described in FIGS. 8 and 9 above.

As described in FIG. 11, guide pipes 19 are added one after another as the excavation progresses.

At this time, the guide pipe fixing device 20 and the guide pipe vertical moving device 21 are used.

By the way, the guide pipe fixing device 20 and the guide pipe vertical movement device 21 are used not only to add the guide pipe 19 but also to pull up the excavation mechanism during the blasting process.
As shown in FIGS. 26 and 27, the clamp fittings 45..., 46 are fitted into the notches 44 formed in multiple stages vertically at four corners of the guide pipe 19.
... are provided in two stages, upper and lower, corresponding to the notches 44 of some of the four corners, and each clamp fitting 45, 46 is provided with a hydraulic cylinder device 47, 48.

When pulling up the excavation mechanism, first the upper hydraulic cylinder device 47 clamps the guide pipe 19 with the clamp fitting 45.

Next, the hydraulic cylinder device 4 of the guide pipe vertical movement device 21
9, the lower clamp fitting 46 and the cylinder device 4
8 is attached to the lifting platform 50 is lowered to the lower limit, and then the clamp fitting 4 is lowered by the lower hydraulic cylinder device 48.
At step 6, the guide pipe 19 is clamped.

Thereafter, the upper hydraulic cylinder device 47 is returned and the clamp fitting 45 is removed from the guide pipe 19.

In this state, the hydraulic cylinder device 49 of the guide pipe vertical movement device 21 is raised and stopped at the upper limit, and then the guide pipe 19 is clamped by the clamp fitting 45 by the upper hydraulic cylinder device 47, and then the lower hydraulic pressure is Return the cylinder device 48 and remove the clamp fitting 46 from the guide pipe 19.

By sequentially repeating this operation, the guide pipe 19 is reliably raised.

The above description is an explanation of the operation when pulling up the excavation mechanism during blasting, but when the guide pipes 19 are to be successively added as the excavation progresses, it is sufficient to perform the operation opposite to the operation when lifting the excavation mechanism.

At this time, the entire excavator 11 is pushed down.

Also, when the excavator 11 cannot be lowered by its own weight, or when earth pressure or frictional force acts on the outer surface of the skin plate 15, it becomes possible to overcome these forces and push it down using hydraulic pressure.

Considering the push-down reaction force at this time, the weight of the gantry crane 5 and the fixing force of the foundation 4 of the gantry crane 5 are set.
The portal crane 5 does not float up due to the push-down reaction force.

The method of excavating foundations for steel towers, etc. according to the present invention can be carried out as described above. A portal crane is installed on the foundation constructed on level ground, an excavator is assembled inside the portal crane, and this excavator is While the excavator is supported by a guide pipe to the portal crane, the earth and sand are excavated while the excavator is lowered.As the excavation progresses, a liner is attached to the upper end of the skin plate that is installed around the excavator so as to be in contact with the inner surface of the excavation hole. The feature is that the excavator is pulled up after adding plates and forming an excavation hole of a predetermined diameter and predetermined depth, so that the excavator can be lowered reliably using the guide pipe, and furthermore, the inner surface of the excavation hole can be prevented from collapsing. This can be reliably prevented by the skin plate and liner plate, and the excavation work can be carried out efficiently and easily.

[Brief explanation of the drawing]

The drawings show an example of the implementation of the present invention, and FIGS.
Figure 0 is an explanatory diagram showing the construction order of foundation excavation, Figure 21 is an enlarged vertical front view of the excavator, Figure 22 is an enlarged longitudinal side view of the excavator,
23 is a plan view of the guide pipe, FIG. 24 is a front view of the guide pipe positioning device, FIG. 25 is a plan view of the same, FIG. 26 is a front view of the guide pipe, and FIG. 27 is a plan view of the guide pipe. 3...Flat land, 4...Foundation, 5...
・Gate type crane, 6... Grab bucket, 7
, 8... Hoist, 9... Guide pipe positioning device, 10... Leg material, 11...
... Excavator, 12 ... Excavation scraping packet,
13...Hydraulic motor, 14...Swivel base, 15...Skin plate, 18...
Breaker, 19... Guide pipe, 20...
... Guide pipe fixing device, 21 ... Guide pipe vertical movement device, 22 ... Liner plate, 23 ... Drifter, 24 ... Hole, 2
5...Blasting material, 26...Drilling hole, 27
...Reinforcing bar, 29...Mortar, 30~
33.35-37...Hydraulic cylinder device, 38
... Hydraulic motor, 39 ... Hydraulic cylinder device, 41 ... Positioning fixture, 44 ...
...Notch part, 45, 46... Clamp fitting, 47-49... Hydraulic cylinder device, 50.
...lifting platform.

Claims (1)

[Claims] 1. A gantry crane is installed on a foundation constructed on level ground, an excavator is assembled inside the gantry crane, and earth and sand is excavated while the excavator is lowered while being supported by a guide pipe to the gantry crane. As the excavation progresses, a liner plate is added to the upper end of a skin plate provided around the excavator so as to be in contact with the inner surface of the excavation hole, and the front and rear excavators are pulled up after the excavation hole has been formed to a predetermined diameter and depth. Foundation excavation method for steel towers, etc.