JPH0340765B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to deep foundations in the field of civil engineering and construction;
Alternatively, the present invention relates to a method for constructing joint piles for erected piles used for earth retaining walls and the like.

(Conventional technology) Construction methods using long steel pipe piles are widely used to construct deep foundations and earth retaining walls. A means of constructing to a required depth using the hydraulic pushing method has been appropriately implemented.

Therefore, in order to support even larger facilities,
A hollow insertion method has also been developed, and Japanese Patent Publication No. Sho 52-11131 discloses a method for erecting deep foundation piles as a method for sinking existing stepped piles (hereinafter referred to as Invention A).

FIG. 20 is a schematic vertical cross-sectional view showing the state of sinking of a long erected pile for explaining invention A. A cylindrical casing 1 is sunk to a predetermined depth in the ground by a hollow digging method, and small-diameter lower piles 2a and 2b are similarly sunk into the cylindrical casing 1 using an underwater excavation device 3, a pressing device 4, etc. At the same time, the small diameter lower pile 2
A large-diameter upper pile 5a is attached to b by welding means, etc., and stepped piles 6 consisting of the small-diameter lower piles 2a, 2b and large-diameter upper piles 5a, 5b are formed by sequentially digging and erecting. Build deep.

Thereafter, the cylindrical casing 1 is pulled out and a filler is filled between the outer peripheral surface of the stepped pile 6 and the hole wall, and the vertical load and horizontal load acting on the upper part of the foundation pile are applied to the large diameter. The present invention provides a means for efficiently sinking ideal stepped piles by applying the small-diameter lower pile to the lower part of the foundation pile, which only needs to bear the vertical load.

(Problems to be Solved by the Invention) In the invention A, after the cylindrical casing 1 is erected on the ground and press-fitted, following the initial process of excavating the inside to make it hollow using the muddy water method, At the end of the second step of erecting the piles and sinking them using the medium digging method, we use a method of welding the lower end of the large-diameter upper pile, which is shaped like a truncated cone, and the upper end of the small-diameter lower pile. However, there are problems in that the cost of processing the truncated cone and the welding cost are high, and the working time is unexpectedly long.

In addition, after the stepped pile has been set, there is a step of pulling out the cylindrical casing 1 and a step of filling a filler (usually concrete) between the outer circumferential surface of the stepped pile and the hole wall. There are problems in that it takes a long time and requires special tools, which increases the work cost, and it is not economical to construct foundation piles such as Izutsu construction, which requires the use of a large number of long piles. From this point of view, it could not be adopted, and an improved method was desired.

(Means for Solving the Problems) The present invention provides a method that allows erecting piles to be sunk to a predetermined depth in a short period of time, and also allows building a large number of piles extremely economically. The purpose of this invention is to provide a method for quickly and economically constructing foundation piles with very large depths, and its other purpose is to provide a method for quickly and economically constructing foundation piles with very large depths. The object of the present invention is to provide a method suitable for constructing well-shaped foundations for buildings.

The present invention is a method for achieving the above objects,
When constructing an erected pile using multiple steel pipe piles with different pipe diameters, a protrusion is placed in advance on the inner peripheral surface of the joint of each steel pipe pile, and while excavating the ground, the steel pipe pile is A construction method characterized by inserting and press-fitting the piles in order from the largest piles so that their joints overlap, and after erecting the final pile to a predetermined depth, filling the inside of the steel pipe pile with concrete. The summary is the method of constructing joint piles.

(Function) In the method of the present invention, after a large-diameter pile is press-fitted into a medium excavation, small-diameter piles are sequentially inserted and vertically installed by press-fitting into a medium excavation. It is possible to easily construct piles, and the amount of excavation can be reduced compared to the above-mentioned Invention A.

Furthermore, since the connecting pile means is a means for joining the piles together with concrete, it is very simple and costs significantly less than welding means.

At this time, if a method of partially filling the joint is used for the joint pile, the concrete cost can be further reduced.

Furthermore, since there is no complicated process of press-fitting the cylindrical casing and pulling it out again as in the above-mentioned invention A, the cost of working equipment, tools, etc. is also small.

Furthermore, in terms of load-bearing capacity, similar to the stepped piles, vertical loads and horizontal loads can be borne by the large-diameter piles at the top, and the purpose can be achieved by mainly bearing only the vertical loads at the bottom. For this reason, economic efficiency can be achieved by using piles with the smallest diameter within the limits of the design.

Therefore, in the present invention, there is no need to weld steel pipe piles with different pipe diameters using a member processed into a truncated cone shape, so there is no need to consider restrictions on the type of steel pipe piles, and it is possible to use ready-made products or new products. Regardless of the purpose, you can freely select the most suitable steel pipe pile and perform economical design.

In addition, in the present invention, if a steel pipe sheet pile (either square or round type is used) is used for the upper part, it is structurally very strong and has excellent performance against horizontal and vertical loads. Foundations for earth retaining can be constructed economically.

(Example) Hereinafter, the present invention will be described in detail according to an example shown in the drawings.

FIG. 1 is a schematic partial sectional view showing an intermediate process of press-fitting a steel pipe pile into a trench in the present invention. After the upper steel pipe pile 11 is erected by the hollow press-in method, the support pipe 13 is connected to the lower steel pipe pile 12, and the hollow press-in is carried out. Shown in Figure 2 a, b, and c.

Fig. 2a is a schematic partial cross-sectional view showing the state in which the earth auger 8 is inserted into the inside of the upper steel pipe pile 11 and press-fitting into the trench has started, and Fig. 2b is a schematic partial cross-sectional view showing the state in which the earth auger 8 is inserted into the inside of the upper steel pipe pile 11 and press-fitting is started. The lower steel pipe pile 12 connected to the support pipe 13 is inserted into the upper steel pipe pile 11 from which earth and sand has been removed, and the support pipe 13 and the lower steel pipe pile 12 are
Fig. 2c is a schematic partial cross-sectional view showing the situation where the earth auger 8 is inserted into the hole and press-fitting is started;
The lower steel pipe pile 12 is sunk to a predetermined depth,
This is a schematic partial cross-sectional view showing the situation just before pulling out the earth auger 8. The same procedure is followed when sinking three or more steel pipe piles, but the leader 14 and the earth auger 8 are set to appropriate lengths. Needless to say, we will adopt the one from

Next, FIGS. 3 to 6 show the steps for hardening the tip of the long erected pile 15, which consists of the upper steel pipe pile 11 and the lower steel pipe pile 12, which were erected by the above-mentioned hollow press-in method, and the connecting pile procedure. As shown in FIG. 3, the foot protection rod 16 is inserted into the long erected pile 15, and a high-pressure water injection device (not shown) is attached to the upper part of the support pipe 13. , high-pressure water is injected from the cutting edge 17 of the root hardening rod 16 to clean the inside of the steel pipe and excavate the cavity 18 at the tip. Then, the water is switched to cement milk, and the bulb 19 is sprayed as shown in FIG. , and then pull out the support tube 13.

Next, as shown in FIG.
A reinforcing bar basket 21 having a structure is connected to a joint 23 of a long erected pile 15 using iron wires 22a and 22b (details will be described later).
hang it in position.

24a and 24b in FIG. 5 are the iron wires 22a and 2
2b is shown. Next, as shown in FIG. 6, the joint portion 23 is partially filled with concrete 25 using a tremie pipe (not shown), and the long erected pile 15 is jointed. The iron wires 22a and 22b are cut into the upper steel pipe pile 11. In this embodiment, only a small amount of concrete can be used, and the construction period can be extremely short.

Now, FIG. 7 is a schematic cross-sectional view of a long erected pile 27 in which, in addition to the above-mentioned upper steel pipe pile 11 and lower steel pipe pile 12, a tip steel pipe pile 26 is attached.
In this example, which is for a large depth of 100 m, the entire inside of the long erected pile 27 is filled with concrete, and reinforcing bars may be inserted as appropriate, but reinforcing bars may be inserted in places where there is little need for reinforcing bars. You are also free to omit it.

In the present invention, when two steel pipe piles with different diameters are installed vertically, that is, the lower steel pipe pile 12 in FIG.
is called the final pile, and when three steel pipe piles with different diameters are connected as shown in FIG. 7, the tip steel pipe pile 26 is called the final pile.

In addition, since the present invention vertically installs steel pipe piles with different diameters by sequentially inserting them, the first steel pipe pile to be sunk becomes the largest diameter steel pipe pile. The square steel pipe sheet pile becomes the maximum diameter steel pipe pile. However, when steel pipe piles of the same diameter are connected, they are collectively referred to as the maximum diameter steel pipe pile. In this case, the pipe diameter refers to the length of the short side of the square steel pipe sheet pile.

Next, details of the joint pile means will be further explained.

FIG. 8 is a partially enlarged cross-sectional view of the peripheral area A of the joint 23 in FIG. You only need to pay for the joint part 2.
3, there is little need to provide a highly rigid connecting pile means, so the upper steel pipe pile 11 and the lower steel pipe pile 12 are spaced appropriately, for example, 500 to 1000, as shown in FIG.
If they are overlapped by about 1/2 mm and joined by concrete filling, it is possible to achieve the purpose sufficiently in terms of strength.

In the present invention, the joint section refers to the overlapping portion of the upper and lower ends of the steel pipe pile as described above, and the joint pile refers to the joining of the upper and lower steel pipe piles using the joint section.

If it is desired to increase the joint strength of the joint 23, as shown in the schematic cross-sectional view of FIG. Weld 28b or
Alternatively, in addition to welding the annular steel bars 29a and 29b as shown in the partially cutaway perspective view of FIG.
As shown in the partial sectional view of FIG. 1, a steel pipe pile 31 provided with a spiral protrusion 30 is employed.

In the present invention, when carrying out load transmission between steel pipe piles with different shapes and dimensions, such as the dowels 28a and 28b, the annular steel bars 29a and 29b, and the spiral protrusion 30, through concrete, the Members that increase adhesive shear strength are collectively referred to as protrusions.

When providing such protrusions, it is desirable to adopt a shape and size that does not cause any hindrance to the insertion of the next stage steel pipe pile, earth auger, or foot protection rod.

Further, when partially filling the joint portion during the connection, a closing plate 32 is used as shown in FIG. 9, and its locking means are the same as in the example shown in FIG. 5.

Next, an example in which the method of the present invention is utilized for constructing the foundation of a large-scale chemical device will be described.

FIG. 12 is a schematic perspective view showing the structure of the foundation,
The chemical equipment 33 (only one part is shown for the sake of explanation) is fixed on a basic concrete slab 35 with reinforcing support legs 34a to 34c, which has square steel pipe sheet piles 36 with joints (in the explanation). For convenience, only one member is designated by a reference numeral).

In addition, a lower steel pipe pile 38 is attached to the square steel pipe sheet pile 36.
is vertically installed by half of the total length by the above-mentioned hollow press-fit (see Fig. 19), and a bulb 19 is constructed at its tip to support the vertical load.

In this embodiment, the length of the Izutsu panel 37 is 30.5
m (4.5 m above ground, 26 m underground), and the length of the lower steel pipe piles 38 was 30 m, with each pile overlapping about 1 m.

In addition, the diameter of the well panel 37 is approximately 12.6 m,
The square steel pipe sheet pile used as the upper steel pipe pile has an outer diameter of 800 mm and a plate thickness.
The lower steel pipe pile 38 has an outer diameter of 12 mm.
A 700mm and 12mm plate thickness was used.

In order to set the length of the above-mentioned well panel 37 to 30.5 m, unit square steel pipe sheet piles of 15 m and 15.5 m were connected by welding means, which is approximately the same as the means shown in Fig. 2 a to c above. It was deposited by means of

The situation is shown in FIGS. 13 to 15. 13th
The figure shows a situation in which square steel pipe sheet piles 36a and 36b are welded together and press-fitted into a hollow using an earth auger 8. The figure shows steel pipe pile 38a
is inserted into the square steel pipe sheet piles 36a and 36b, and the support pipe 1
16 and 17 are used as the square steel pipe sheet piles.
, the square steel pipe sheet pile 36 shown in the schematic plan view of FIG.
c, 36b, and 36e are used alone or in combination as appropriate.

FIG. 19 shows the well panel 37 according to one embodiment.
In the partial plan view of a, steel pipe piles 38b are inserted every other square steel pipe pile 36e inside the square steel pipe sheet pile 36e, and it can be easily adapted to the desired curvature of the well, and has high strength against horizontal loads. , stable supporting capacity for buildings can be expected.

(Effects of the Invention) The method of the present invention requires only a small amount of excavation, so long piles can be constructed in a short period of time, less concrete is used, and there is less welding between steel pipes, so it can be constructed economically. When constructing foundations and earth retaining structures, the economic effect is extremely large, and in terms of civil engineering strength, there is no inferiority to conventional methods, so the effect is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a schematic partial cross-sectional view showing the process of press-fitting a steel pipe pile according to the present invention, Fig. 2 a, b, c
3 to 6 are schematic partial sectional views illustrating the procedure of the tip cementing and connecting pile according to the present invention,
Figure 7 is a schematic partial cross-sectional view of a long built-in pile, Figure 8 is a partial enlarged cross-sectional view of the joint and its surrounding area, Figure 9 is a partial enlarged cross-sectional view of the joint with a protrusion, and Figure 10. 11 is a partial cross-sectional view of a steel pipe pile with a spiral projection; FIG. 12 is a schematic perspective view of the basic structure of a chemical equipment; FIG. 13 - Figure 15 is an explanatory diagram showing the construction procedure of Izutsu panels, Figures 16 to 18 are plan views of square steel pipe sheet piles, Figure 19 is a partial plan view of Izutsu panels, and Figure 20 is a conventional long construction. It is an explanatory diagram of the setting situation of pile piles. 1... Cylindrical casing, 2a, 2b... Small diameter lower pile, 3... Underwater excavation device, 4... Pressing device, 5
a, 5b...Large diameter upper pile, 6...Stepped pile, 7...Erection work vehicle, 8...Earth auger, 9...Earth auger drive device, 10...Press device, 11...Upper steel pipe Pile, 12... lower steel pipe pile, 13... support pipe,
14... Leader, 15... Long erected pile, 16...
Root hardening rod, 17... Tip cutting edge, 18... Tip cavity, 19... Bulb, 20... Obstruction plate, 21...
... Rebar basket, 22a, 22b ... iron wire, 23 ... joint, 24a, 24b ... fastener, 25 ... partial filling, 26 ... tip steel pipe pile, 27 ... long erected pile,
28a, 28b... Jibel, 29a, 29b...
Annular steel bar, 30...Spiral projection, 31...Steel pipe pile, 32...Closure plate, 33...Chemical device, 34a
~34c...Reinforcement support leg, 35...Foundation concrete plate, 36, 36a-36e...Square steel pipe sheet pile,
37, 37a...Izutsu panel, 38, 38a, 3
8b...Lower square steel pipe pile.

Claims (1)

[Scope of Claims] 1. When constructing a built-in pile using a plurality of steel pipe piles with different pipe diameters, a protrusion is placed in advance on the inner peripheral surface of the joint of each steel pipe pile, and the ground is excavated. Then, the steel pipe piles are inserted and press-fitted in order from the largest diameter, so that their joints overlap, and after the final steel pipe pile is erected to a predetermined depth, concrete is poured inside the steel pipe pile. A method for constructing a joint pile for an erected pile, which is characterized by filling the pile. 2 Place a blocking plate below the lower joint,
2. The method of constructing a joint pile for an erected pile according to claim 1, characterized in that the joint portion is filled with concrete, and the upper joint portions are sequentially filled with concrete. 3. A method for constructing a joint pile for an erected pile according to claim 1, characterized in that the entire inside of the steel pipe pile is filled with concrete. 4. A method for constructing a joint pile for an erected pile according to claim 2 or 3, characterized in that a steel pipe sheet pile is used at the top of the steel pipe pile.