JPH1150441A - H-shaped steel pile having liquefaction controlling function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide drainage members to an H-shaped steel pile as a footing pile, efficiently control liquefaction of the ground around the pile in the case where an earthquake occurs and to promote an economic design and execution efficiency of the pile. SOLUTION: Drainage members 5a of channel steel, etc., are mounted to web and/or flange of an H-shaped steel 6 forming an H-shaped steel pile 2 by means of welding, etc., to form a drainage space. For a section located in the liquefaction ground 3 of the drainage members 5a, a large number of openings having earth and sand incursion preventing filters are formed. The upper ends of the drainage members 5a are extended to a drainage treatment crushed stone layer 4 of the pile head. When an earthquake occurs, pore pressure in the liquefaction ground 3 is raised, excessive pore water in the liquefaction ground 3 is drained to the drainage treatment crushed stone layer 4 through the insides of the drainage members 5 mounted to the H-shaped steel pile 2, and the liquefaction around the H-shaped steel pile 2 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an embankment, a building,
The present invention relates to an H-shaped steel pile having a liquefaction-suppressing function, which is used for structural foundations in the field of civil engineering and construction such as bridges and tanks.

[0002]

2. Description of the Related Art Piles used as structural foundations can be classified into steel piles, concrete piles, composite piles, etc. Among them, steel piles are further classified into steel pipe piles and H-shaped steel piles. It is used according to.

Further, as a countermeasure against liquefaction for the ground which may be liquefied, a large number of openings are provided in a predetermined section of a grooved steel material such as a channel steel, and a filter for preventing intrusion of earth and sand is attached to the openings. There is a liquefaction countermeasure method in which a drainage member is attached to a steel pipe pile or steel sheet pile (Japanese Patent Laid-Open No. 22571/1990).
No. 0, JP-A-2-225712, etc.), and is applied to the ground where liquefaction is expected to occur.

[0004]

Problems to be solved by liquefaction when an H-shaped steel pile is used as a structural foundation have the following problems.

[0005] Even if liquefaction countermeasures are taken for the surrounding ground of the structure, it is difficult to avoid transmission of excess pore water pressure from the surrounding ground to the ground below the structure.

In the case of liquefaction, if the surrounding ground resistance cannot be taken into account, a necessary resistance is required, so that a large number of steel piles are generally required, which is difficult in terms of construction period and cost.

In some cases, the method may be used in combination with a ground improvement method by injecting a chemical solution or the like, but there are difficulties in terms of work period and cost.

[0008] The present invention has been made to solve the above-mentioned problems, and a drainage member is provided on an H-shaped steel pile as a foundation pile to effectively prevent liquefaction of the ground around the pile during an earthquake. This enables the economic design of piles and the improvement of workability.

[0009]

According to a first aspect of the present invention, an H-shaped steel pile having a liquefaction-inhibiting function is provided at least in a predetermined section located in the ground where liquefaction may occur. A large number of openings provided with filters for preventing liquefaction, and a drainage member for preventing liquefaction forming a drainage channel inside is attached along the longitudinal direction of the flange and / or web of the H-shaped steel pile. It is characterized by the following.

[0010] It is sufficient that at least a part of the drainage member is attached to the flange or the web of the H-shaped steel pile.

[0011] Excess pore water during an earthquake passes through a drainage member attached to the web surface and / or the flange surface of the H-shaped steel pile, and from the liquefied layer with increased pressure to the ground surface or near the ground surface. By discharging to the crushed stone layer, liquefaction of the ground around the H-shaped steel pile is suppressed.

Therefore, the ground resistance around the H-shaped steel pile can be taken into consideration even at the time of liquefaction, which is an economical design for designing the H-shaped steel pile.

[0013] Further, in the construction, an H-shaped steel pile attached with a drainage member and having a liquefaction suppressing function can be driven in the same manner as a conventional H-shaped steel pile, so that a special construction method, construction equipment and the like are required. It is unnecessary, the workability is good, and the construction period can be shortened.

According to a second aspect of the present invention, in the H-shaped steel pile having the liquefaction-suppressing function according to the first aspect, the drainage member attaches both ends of a groove-shaped cross section to a flange or a web of the H-shaped steel pile. In, a flange-shaped member that forms a drainage channel between the flange or the web surface of the H-shaped steel pile, and along a longitudinal direction, at least a predetermined section located in the ground where liquefaction is likely to occur, This is limited to the case where a large number of openings provided with filters for preventing intrusion of earth and sand are provided.

As the groove member, in addition to a general groove steel,
Various members molded or processed into a U-shaped cross section or other groove shapes can be used.

According to a third aspect of the present invention, in the H-shaped steel pile having the liquefaction suppressing function according to the first aspect, the drainage member is a member having a hollow cross section attached to a flange or a web of the H-shaped steel pile. Along the longitudinal direction, at least for a predetermined section located in the ground where liquefaction is likely to occur, the case where a large number of openings provided with filters for preventing infiltration of earth and sand are provided is limited. Things.

As the drainage member, a member having a hollow section such as a circle, an ellipse, or a square, which can form a drainage channel by itself, is used.

The H-shaped steel pile having the liquefaction inhibiting function according to claim 4 of the present application has a filter for preventing infiltration of earth and sand at least in a predetermined section located in the ground where liquefaction may occur. With a number of openings with
A liquefaction-preventing drainage member having a drainage channel formed inside is installed near an H-shaped steel pile as a foundation pile.

As the material of the drainage member, a metal material such as steel or a synthetic resin material can be used. The cross-sectional shape is generally a circular or square pipe shape, but there is no particular limitation as long as a drainage channel can be formed inside.

Further, in the vicinity of the H-shaped steel pile referred to here, H
There are a case where it is in contact with the shaped steel pile and a case where it is separated from the H-shaped steel pile. It is necessary to be able to expect the ground resistance around the H-shaped steel pile at the time of liquefaction even if it is separated from the H-shaped steel pile. It is desirable to stay within the range that can be suppressed.

Also in this case, as in the case of the H-shaped steel pile according to the first aspect, excessive pore water during the earthquake passes through the drainage member made of steel or synthetic resin, and is discharged from the liquefied layer where the pressure is increased. The liquefaction of the ground around the H-shaped steel pile is suppressed by being discharged to the crushed stone layer on or near the ground surface,
Even during liquefaction, the ground resistance around the H-shaped steel pile can be considered.

[0022]

FIG. 1 shows an embodiment in which an H-shaped steel pile having a liquefaction inhibiting function according to the present invention is applied to a pier foundation such as an embankment or a bridge.

In this example, as shown in FIG. 1 (a), it is assumed that a foundation 1 supported by H-shaped steel piles 2 is constructed in a landfill ground divided by a sheet pile 7. During,
Reference numeral 3 denotes a ground (liquefied ground) that is likely to be liquefied and consists of a loosely saturated sand ground.

FIG. 1 (b) shows a horizontal section of the H-shaped steel pile 2 portion. The drainage member 5a made of a channel steel is provided on the web and flange of the H-shaped steel 6 constituting the H-shaped steel pile 2. Is attached by welding or the like, and a drainage space for dissipating excess pore water pressure in the liquefied ground 3 during an earthquake is formed between the web and the flange.

Although not shown, the section of the drainage member 5a located on the liquefied ground 3 is disclosed in
Similarly to the drainage member described in JP-A-25710 and JP-A-2-225712, a large number of openings provided with filters for preventing intrusion of earth and sand are formed. Also, in this example, the upper end of the drainage member 5a is located at the top of the pile head for drainage treatment crushed stone layer 4.
Extending to

When an earthquake occurs, the excess pore water pressure in the liquefied ground 3 rises, but the excess pore water in the liquefied ground 3 is discharged from the opening of the drain member 5 a attached to the H-shaped steel pile 2. 5a flows into the pile, and the crushed stone layer 4 for drainage treatment at the pile head
The rise in excess pore water pressure is suppressed by being drained to the water.

FIGS. 2 (a) to 2 (d) show a horizontal section of an H-shaped steel pile portion according to the first and second embodiments.

In the example of FIG. 1 (b), the drainage member 5a is attached to both sides and both flanges of the web of the H-section steel 6, whereas FIG. 2 (a) shows the case where only one side of the web is used.
Fig. 2 (b) shows the case where only two flanges are attached.
Fig. 2 (d) shows the case where the mounting is performed only on the web, and Fig. 2 (d) shows the case where the mounting is performed only on the web.

FIGS. 3 (a) to 3 (e) show a horizontal section of an H-shaped steel pile portion according to an embodiment corresponding to claim 3.
In these examples, a drain member 5c made of a synthetic resin or synthetic fiber having an opening and having a filter in a tube having an elliptical horizontal section is used.

In the example of FIG. 3 (a), the drainage members 5c are attached to both flanges of the H-section steel 6 and both surfaces of the web.

FIG. 3 (b) shows that the drainage member 5c is
Fig. 3 (c) shows the case where it is mounted on only one flange, Fig. 3 (d) shows the case where it is mounted on only one flange, and Fig. 3 (e) shows the case where it is mounted only on the web. Is the case.

FIGS. 4 (a) to 4 (h) and FIGS. 5 (i) to 5 (l) show a horizontal section of an H-shaped steel pile portion according to an embodiment corresponding to the fourth aspect. As the drainage member 5b, a pipe made of synthetic resin, synthetic fiber, or the like having an opening and provided with a filter is used.

In the example shown in FIG. 4A, the drainage member 5b is provided so as to be in contact with both flange surfaces of the H-section steel 6. In this case, the drainage member 5b may or may not be fixed to the flange surface.

FIG. 4 (b) shows a case where the drainage member 5b is provided only on one flange, and FIG. 4 (c) shows a case where the drainage member 5b is provided without directly contacting the vicinity of both flanges. FIG. 4 (e) shows a case where the drainage member 5b is provided without directly contacting the vicinity of one flange, FIG. 4 (f) shows a case where the drainage member 5b is provided so as to contact both sides of the web, and FIG. FIG. 4 (g) shows a case in which the drainage member 5b is provided so as to be in contact with one side of the web.
(h) is a case where the drainage member 5b is provided near one side of the web without directly contacting it.

FIG. 5 (i) shows a case where the drainage member 5b is provided so as to be in contact with both flange surfaces of the H-section steel 6 and both sides of the web, and FIG. This is a case where both flange surfaces and one side of the web are provided in contact with each other.

FIG. 5 (k) shows that the drainage member 5b is
5 (l), the drainage member 5b is provided so as to be in contact with both flange surfaces of the H-section steel 6 when provided so as not to directly contact both sides of the web.
In addition, this is a case where it is provided without directly contacting one side of the web.

[0037]

[Effects of the Invention] As a foundation of structures such as embankments, buildings, bridges, tanks, and the like, an H-shaped steel pile with a liquefaction suppression function for dissipating excess pore water pressure is used to provide a structure in the event of an earthquake. Liquefaction of the lower surface of the object and the surrounding ground can be suppressed, and the stability of the structure during an earthquake can be improved.

Since the liquefaction of the ground around the H-shaped steel pile is suppressed, the ground resistance around the H-shaped steel pile at the time of the earthquake can be taken into consideration, and an economical design becomes possible in designing the H-shaped steel pile. .

When the steel drainage member is mounted so as to be integrated with the H-shaped steel pile, the cross-sectional performance as a steel material is increased, and the lateral flow countermeasures, etc., are higher than when the H-shaped steel pile is used alone. Is also effective.

[Brief description of the drawings]

FIG. 1 shows an embodiment in which the present invention is applied to a pier foundation of a bridge, where (a) is a vertical sectional view, and (b) is H
It is a horizontal sectional view of a shape steel pile part.

2 (a) to 2 (d) are horizontal sectional views of an H-shaped steel pile portion showing an embodiment corresponding to claims 1 and 2 of the present application, respectively.

FIGS. 3 (a) to 3 (e) are horizontal cross-sectional views of an H-shaped steel pile portion showing an embodiment corresponding to claim 3 of the present application.

4 (a) to 4 (h) are horizontal sectional views of an H-shaped steel pile portion showing an embodiment corresponding to claim 4 of the present application.

FIGS. 5 (i) to (l) are horizontal sectional views of an H-shaped steel pile portion showing an embodiment corresponding to claim 4 of the present application.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Foundation, 2 ... H-shaped steel pile, 3 ... Liquefaction ground, 4 ... Crushed layer for wastewater treatment, 5a, 5b, 5c ... Drainage member, 6 ... H-shaped steel, 7 ... Sheet pile

Claims (4)

[Claims] At least a predetermined section located in the ground where liquefaction is likely to occur, a large number of openings provided with filters for preventing infiltration of earth and sand, and a liquid forming a drainage channel inside. A liquefaction-preventing drainage member attached along the longitudinal direction of the flange and / or web of the H-shaped steel pile;
Shaped steel pile. 2. The drainage member comprises a groove-like member which forms a drainage channel between the flange and the web surface by attaching both ends of the groove-shaped cross section to a flange or a web of the H-shaped steel pile. A plurality of openings provided with a filter for preventing infiltration of earth and sand are provided at least in a predetermined section located in the ground where liquefaction is likely to occur along the longitudinal direction. H-shaped steel pile with liquefaction prevention function. 3. The drainage member is a member having a hollow cross section attached to a flange or a web of the H-shaped steel pile, and is located along a longitudinal direction at least in a ground where liquefaction may occur. The H-shaped steel pile according to claim 1, wherein a plurality of openings provided with filters for preventing intrusion of earth and sand are provided in a predetermined section. 4. At least a predetermined section located in the ground where liquefaction is likely to occur, a large number of openings provided with filters for preventing infiltration of earth and sand, and a liquid forming a drainage channel inside. An H-shaped steel pile having a liquefaction inhibiting function, wherein a drainage member for preventing liquefaction is installed near the H-shaped steel pile.