JPS5985028A - Steel pipe pile and laying work thereof - Google Patents

Abstract

PURPOSE:To make easier the laying work of a steel pipe pile as well as simplify the structure of the pile and reduce the cost of the laying work by a method in which a bottom plate having a grout jet nozzle and an excavating blade is fixed to the lower end of a pile, and a spiral blade is provided to the lower end of the pile. CONSTITUTION:A steel pipe pile 1 is penetrated into the ground while being turned and while excavating the ground by its excavating blade 4, and cement milk is injected from a grout jet nozzle 3 into an excavated pit 7, whereby forming a spiral supporting layer 8 on the surrounding of the pile 1. After the pile 1 is penetrated to a given depth into the ground, the steel pile 1 is repeatedly moved vertically while being turned to form a footing lump 9 with the injection of cement milk in the lower end part including the spiral blade 5 of the pile 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a poured steel pipe pile suitable as a foundation pile particularly in soft ground and a method for burying the same.

In general, the foundations of houses are constructed using independent foundations, cloth foundations, or solid foundations, and there is no problem with good quality ground. Increasingly, houses are being built on soft ground, which has not yet been built, and with the above-mentioned general foundation structure, houses tend to sink over time due to uneven ground subsidence, etc. Accidents resulting in deformation and trouble are occurring frequently.

Improvement methods for such soft ground include the sand pile method, plastic board train method, preloading method, and cement-lime method. , friction pile method and support pile method.

However, all of these construction methods are used for large-scale construction works on large sites, and are designed to support large loads. , its use is difficult due to construction scale, load conditions, economic efficiency, etc.

The current construction method is to support the upper load by driving wooden piles, small-diameter concrete piles, or small-diameter steel pipes, but this method has problems with noise and vibration when used in densely populated residential areas. If the supporting ground is deep, the piles will be long, making it uneconomical.

The present invention aims to improve the ground by transporting it into a densely populated residential area and constructing it in soft ground, as well as providing a steel pipe pile that has sufficient strength and supporting capacity as a foundation, and a construction method suitable for burying the pile. Rather than providing a method, the present invention aims to improve the conventional method.

Hereinafter, the steel pipe pile of the present invention and its construction method will be explained with reference to the drawings.

Figure 1 is a side view showing one embodiment of the steel pipe pile of the present invention, Figure 2
The figures are bottom views of the same, and in these figures, 1 is the main body of the pile made of steel pipe, and a bottom plate 2 is fixed to the lower end of the pile body. ing. Also,
A spiral wing 5 is provided protruding from the lower end of the pile body 1 along its outer peripheral surface. In the embodiment, the spiral blade 5 is formed with a continuous number of turns, but the number of turns can be increased or decreased as appropriate, and the spiral blade 5 can be divided into discontinuous sections to form a spiral shape as a whole. It may be formed as follows.

FIG. 3 shows another embodiment of the steel pipe pile of the present invention, which differs from the previous embodiment in that grout injection holes 3, 3 are provided in the bottom plate 2.

The steel pipe pile of the present invention is constructed as described above, and during construction, a rotary pushing drive device (not shown) is attached to the upper end of the pile body 1, and the pile body 1 is pushed in while being driven by the drive device. It is buried underground. Also, the third
In the case of steel pipe piles as shown in the figure, by pouring cement milk into the pile body 1 as necessary, the grouting hole 3 can be
, 3, the cement milk can be injected into the borehole.

Next, to explain the most effective method of burying steel pipe piles as shown in Fig. 3 of the present invention, the steel pipe piles are erected on the ground and pushed into the ground while being rotated by a drive device. For example, the excavation progresses with the digging blade at the lower end, and the steel pipe pile penetrates into the ground. As the steel pipe pile penetrates, a rotation locus 6 due to the spiral blades 5 will be formed in the ground.
By injecting cement milk into the excavated hole 7 under pressure, the cement milk mixes with the excavated soil and fills the area around the pile body 1 and the rotation locus as shown in FIG. 3, creating a spiral peripheral support layer 8. It is formed. After penetrating to a predetermined depth, the steel pipe pile is repeatedly moved up and down while being rotated. As a result, a hardening block 9 is formed at the lower end of the steel pipe pile including the spiral wings 5 by pouring the cement milk, and the construction of the present invention is completed. As a result, in the ground there is a steel pipe pile with spiral wings 5 at the lower end,
The foot protection nodules 9 and the spiral peripheral support layer 8 are integrally connected to this, and function as a foundation pile. In addition, the injection of cement milk can be done by putting the cement milk into the pile body 1 and letting it flow naturally from the spout hole 3, but if necessary, connect an injection pipe etc. to the spout hole 3. It may be forcibly ejected. Further, the inside of the steel pipe pile after penetration may be left hollow, or it may be filled with concrete or the like.

As explained above, the present invention fixes a bottom plate to the lower end of a steel pipe pile body, provides a digging blade or a grout spout hole in addition to this, and has a spiral blade on the outer peripheral surface of the lower end of the pile body. Since the steel pipe pile is constructed by protruding from the pile, there is no need for any special equipment for burying the pile, and the burying can be done by simply rotating and press-fitting the pile itself, and the structure is simple and can be manufactured at low cost. It has a large bearing capacity and is suitable as a foundation pile for houses, etc., especially on soft ground.In addition, this steel pipe pile is rotated and press-fitted, and is buried while pouring cement milk through the grout spout hole. At the lower end of the steel pipe pile, a large-diameter foot-reinforcing mass is formed that is integrally connected with the spiral blade, and around the steel pipe pile, the surrounding support layer overflowing with the rotation trajectory of the spiral blade is integrated with the steel pipe pile. It is possible to significantly increase the bearing capacity of buried steel pipe piles. Therefore, it is possible to use small diameter and short steel pipe piles, and also to reduce the number of them, which greatly reduces the labor and cost of construction. It is particularly effective as a foundation for general housing built on soft ground.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the steel pipe pile of the present invention, Fig. 2 is a bottom view of the same, Fig. 3 is a side view showing another embodiment of the steel pipe pile of the invention, and Fig. 4 is a steel pipe of the invention. It is a side sectional view showing the state of construction of a pile. 1... Pile body 2... Bottom plate 3... Grout injection hole 4... Drilling blade 5... Spiral blade 6... Rotation locus of spiral blade 7... Drilling hole
8... Peripheral support layer 9... Patent applicant for root solidifying baby boomers Yoshi 1) Koyoshi

Claims (3)

[Claims] (1) A steel pipe pile, characterized in that a bottom plate is fixed to the lower end of a steel pipe pile body, a digging blade is provided on the bottom plate, and spiral wings are protruded from the outer peripheral surface of the lower end of the pile body. (2) The steel pipe pile according to claim 1, characterized in that the bottom plate is provided with grout injection holes. (3) The lower end of the pile body K, the grouting hole, and the bottom plate with the excavation blade are fixed, and the steel pipe pile with spiral blades protruding from the lower end is rotated and inserted into the ground while grouting the hole. More cement milk is injected to form a spiral peripheral support layer around the steel pipe pile, and after the steel pipe pile has penetrated to a predetermined depth, the steel pipe pile is moved up and down while rotating. A method for burying steel pipe piles, which is characterized by forming a foot protection nodule at the bottom end.