JPS6262206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a pile foundation with underground braces.

In general, support piles have a large vertical bearing capacity, but a small horizontal resistance. However, in the case of buildings standing on soft ground or buildings without basements, most of the horizontal force caused by earthquake force and wind pressure is received by the horizontal resistance force of the support piles, and most of the horizontal force is absorbed by the horizontal resistance force of the support piles. Conventional buildings supported by support piles with weak horizontal resistance have had major structural problems. In addition, measures to deal with uneven subsidence have been perfected for a long time.
Therefore, the present applicant increased the horizontal strength and horizontal rigidity of the support piles against horizontal external forces such as earthquakes and wind by providing an underground wall between the support piles driven into the ground and integrally with the support piles. We have also developed a pile foundation with underground walls that reduces displacement and uneven settlement of the pile foundation (see patent application No. 139572).

However, in the invention related to the above patent application, after erecting a support pile and excavating a certain area around the support pile, an underground wall made of cast-in-place concrete is constructed integrally with the support pile, Construction required a great deal of time and effort. Furthermore, no construction method has been considered for installing braces between the support piles that exhibit extremely high resistance to horizontal loads.

This invention is a development and improvement of the above-mentioned patented invention, and it is possible to significantly increase the horizontal strength and horizontal rigidity of the support pile, as well as to prevent uneven settlement, and to shorten the construction period and simplify the construction. The purpose of this paper is to provide a construction method for pile foundations with underground braces that can save labor.

The method for constructing a pile foundation with underground braces according to the present invention is to install a foundation pile in which a joint part is provided on the side of the upper part of the foundation pile over a certain range in the vertical direction (approximately 3 to 7 m from the ground surface). are placed in the ground facing each other, and an excavation groove is excavated between the foundation piles, and then an underground brace pre-assembled in the excavation groove is engaged with the left and right edges of the underground brace in a hook shape to the joint. and while preventing sand from entering the engaging part,
Furthermore, the foundation pile is erected while being guided by the joint, and then the joint of the foundation pile and the end of the underground brace are integrated in the ground with a filling material such as mortar. In addition to the method of excavating and erecting as described above, there is also a method of installing a device to excavate or weaken the ground at the lower end of the underground brace.

According to this invention, since the underground brace is provided between the foundation piles built in the ground and integrated with the foundation piles, the horizontal strength and horizontal rigidity against horizontal external forces such as earthquakes and wind can be significantly increased. displacement and uneven settlement can be prevented.

In addition, during construction, foundation piles with joints on the sides are erected with the joints facing each other, an excavation groove is excavated between the foundation piles, and the foundation piles are assembled on the ground in advance into the excavation groove. The left and right edges of the underground braces are engaged with the joints and guided by the joints, and then the joints between the foundation pile joints and the ends of the underground braces are filled with mortar or concrete. Since the foundation pile and underground brace are integrated into one piece, it is possible to omit the excavation work, cleaning work, and concrete work around the foundation pile that would otherwise be required with conventional construction methods. Therefore, it can be built into an excavated trench extremely easily and quickly, significantly shortening the construction period, simplifying the construction work, and saving labor. In addition, dimensional errors due to variations in the pitch between foundation piles and inclination of the foundation piles can be absorbed very easily by the joints provided on the sides of the foundation piles. In addition, conventional piles such as steel pipe piles and concrete piles can be used, reducing construction costs.

Hereinafter, the construction method according to the present invention will be explained with reference to an illustrative embodiment.
Connect multiple foundation piles 2, 2 with
It is installed in the ground by a driving method or an embedded method, with the joints 1 and 1 facing each other and isolated for an appropriate distance in the ground.

The joint parts 1, 1 are formed by fixing two angle-shaped members to the side surface of the foundation pile 2 by welding or the like so that both of them together form a recess with a substantially lip-groove cross section.
Closing plates 3 are attached to the openings of the lower ends and side surfaces of the joints 1, 1, which are formed in advance on the ground, to prevent soil from entering the joints 1 while the foundation piles 2 are being erected. be. The closing plate 3 that closes the opening on the side surface of the joint 1 is detachably attached, and is configured to be pulled out directly above the foundation pile 2 after it is erected.

Next, an excavation groove 5 is excavated to a predetermined depth so that the underground brace 4 can be installed between the foundation piles 2, 2. Next, the closing plate 3 is pulled out and an underground place is built into the excavated groove 5 with its left and right edges engaged with the joints 1, 1 and guided by the joints 1, 1. Then, in the ground, the joint parts 1, 1 are filled with a filler 6 such as mortar or concrete to integrate the foundation piles 2, 2 and the underground brace 4. At the left and right edge portions of the underground brace 4, engaging portions 7, 7 having a substantially T-shaped cross section are formed to be engaged with the joint portions 1, 1. The engaging portion 7 is previously formed on the ground.

Figures 6, 7, 8, 9 and 10
The figure shows another embodiment of the invention.
7 and 8, a T-shaped cross section is fixed to the side surface of the foundation pile 2 by welding or the like to form joints 8, 8, and the underground brace 4 is connected via a joint metal fitting 9. It is connected to the joint parts 8,8.

The joining hardware 9 consists of an engaging part 10 with a generally lip groove-shaped cross section that can engage the joint part 9, and an engaging part 11 that has a roughly groove-like cross section with which the underground brace 4 can be engaged, and has a groove at its lower end. The blade shape is tapered. In addition, depending on the ground, the blade shape may not be formed at the lower end but may be formed horizontally. The opening surfaces of the lower ends of the engaging parts 10 and 11 are closed, and the engaging parts 1
An opening hole 12 having a substantially T-shaped cross section corresponding to the cross-sectional shape of the joint portion 8 is formed in the bottom portion of the joint portion 8 . A closing plate 3 is detachably attached to the opening surface of the side surface of the engaging portion 11, and the closing plate 3 is configured to be pulled out directly upward. Moreover, shear connectors 17, 17, such as stud bolts, and protrusions 13, 13 are protrudingly provided inside the engaging portion 11.

During construction, after the foundation piles 2, 2 are erected and the excavation groove 5 is excavated, the joining hardware 9 is engaged with the joint part 8 and the engaging part 10 through the opening hole 12, and is guided by the joint part 8. Drive it into the ground. in this case,
Earth and sand adhering to the joint portion 8 can be scraped off at the peripheral edge of the opening hole 12. Furthermore, since a blade shape is formed at the lower end of the joining hardware 9, the work of driving the joining hardware 9 is facilitated.

Next, the closing plate 3 is pulled out, and the left and right edges of the underground brace 4 are engaged with the engaging parts 11, 11 of the joining hardware 9, and the underground brace 4 is guided by the engaging parts 11, 11 in the excavated groove 5. Build it up. Then, in the ground, the engaging portions 10 and 11 are filled with filler 6 such as mortar or concrete to integrate the foundation pile 2, joining hardware 9, and underground brace 4.

Fig. 7 shows an embodiment in which the underground brace 4 is made of a steel frame, and Fig. 8 shows an embodiment in which a part of the underground brace 4 is made of cast-in-place concrete. Casing, code 1
5 is a reinforcing bar, and 16 is a spacer. FIG. 9 shows that the foundation pile 2 is constructed by placing an outer shell steel pipe 19 with the joint 1 fixed on the outer periphery of the precast concrete pile 18, and filling the space between the outer shell steel pipe 19 and the precast concrete pile 18 with concrete 20. This is a constructed example.

Since the present invention has the above configuration, it has the following effects.

Since the underground braces between the foundation piles are well-embedded in the ground, their integrity with the ground in the ground is much higher than that of plate-shaped underground walls. The horizontal strength and horizontal rigidity in the direction of
Uplifting can be completely prevented, and as a result, the horizontal strength and horizontal rigidity of the foundation pile can be significantly increased, and uneven settlement of the foundation pile can also be completely prevented.

In addition, since the joints on the sides of the foundation pile are formed only over a certain range at the top of the foundation pile, which is susceptible to the greatest horizontal force, the joints do not need to be formed over the entire length of the foundation pile. It is easy to manufacture, saves on materials, and when driving foundation piles, there is less friction with the ground, making it easier to drive foundation piles, and has extremely high workability.

In addition, when installing underground braces, an excavation trench of a predetermined depth is dug between the foundation piles, and the underground brace is installed in this excavated trench, so it is possible to ensure that the underground brace is installed exactly as specified. In this respect as well, the workability is extremely high.

In addition, dimensional errors due to variations in the spacing between foundation piles and inclination of the foundation piles can be absorbed very easily at the joints. Additionally, since conventional piles can be used, construction costs can be reduced.

[Brief explanation of the drawing]

The first to third drawings are process diagrams of the construction method according to the present invention, Fig. 4 is a cross-sectional view of the constructed foundation pile with underground braces, Fig. 5 is a partial side view thereof, Fig. 6, 7, 8 and 9 show other embodiments of the present invention.
9 and 9 are partial cross-sectional views of the foundation with underground braces, and FIG. 10 is a partial side view thereof. 1...Joint part, 2...Foundation pile, 3...Closing plate,
4... Underground wall or underground brace, 5... Excavation trench, 6... Filling material, 7... Engaging part, 8... Joint part, 9... Joining hardware, 10, 11... Engaging part ,1
2...Opening hole, 13...Protrusion, 14...Casing, 15...Reinforcing bar, 16...Spacer, 17
... Shear connector, 18 ... Precast concrete pile, 19 ... Steel shell pipe, 20 ... Concrete.

Claims (1)

[Claims] 1. A plurality of foundation piles having joints extending over a certain range in the vertical direction on the sides of the upper part of the foundation piles are erected into the ground with the joints facing each other, and then an excavation groove is excavated between the foundation piles. The left and right edges of the underground braces pre-assembled in the excavated trench are engaged with the joint in a hook-like manner, and while preventing sand from entering the engaging part, the joint is 1. A method for constructing a pile foundation with underground braces, which comprises: sinking the foundation pile while guiding the foundation pile, and then integrating the joint part of the side part of the foundation pile and the end part of the underground brace with a filling material.