JP2019007132A - Construction method of steel pipe sheet pile well foundation - Google Patents

Abstract

To provide a construction method of steel pipe sheet pile well foundation allowing appropriate filling of mortar in a joint for connecting adjacent steel pipe sheet piles.SOLUTION: In a construction method of steel pipe sheet pile well foundation in which joints 2 of adjacent steel pipe sheet piles 1 are fitted to each other and multiple steel pipe sheet piles 1 are placed into the ground G of a water bottom G1, and closedly combined to form the foundation, a scouring state of the ground G placed with the multiple steel pipe sheet piles 1 is surveyed, and at least one of a countermeasure of precedent improvement of a ground area where the scouring is expected, and a countermeasure of filling a grout leakage preventive material 4 to the scoured recessed part M of a scoured area to cover the joint 2 exposed by scouring, is performed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a construction method for a steel pipe sheet pile well foundation.

  Conventionally, steel pipe sheet pile well foundations are often used as the basic form of large bridges in rivers and the sea (see, for example, Patent Document 1 and Patent Document 2).

  When constructing this steel pipe sheet pile canopy foundation, a steel pipe sheet pile is cast, soil and sand in the joint are washed and mortar filled, bottom concrete is cast, and drainage in the pipe is performed. And a frame is constructed while ensuring a dry environment inside a steel pipe sheet pile well that functions as a temporary cutoff under the surface of the water.

  In addition, when filling mortar in a joint that connects adjacent steel pipe sheet piles, a grout jacket is used above the ground surface, whereas the ground is used as a substitute for the formwork below the ground surface.

JP 2001-214457 A JP 55-114715 A

  However, as shown in FIG. 3 (a), FIG. 3 (b), and FIG. 3 (c), the ground G outside the steel pipe sheet pile 1 is scoured during mortar filling in the joint 2 that connects the adjacent steel pipe sheet piles 1 to each other. (Scouring recess M).

  In this case, since the joint 2 of the scouring recess M is not covered by the ground G, the grout P injected into the inside of the joint 2 leaks from the gap of the joint 2 and the mortar unfilled place in the joint 2 Can be done. Moreover, when the mortar unfilled part is made in the joint 2, the integration of the steel pipe sheet pile 1 by the joint 2 may be insufficient, or water leakage may occur from the unfilled part during drainage in the well, and drainage may be difficult. .

  In view of the above circumstances, an object of the present invention is to provide a method for constructing a steel pipe sheet pile well foundation that enables mortar filling of a joint that connects adjacent steel pipe sheet piles.

  In order to achieve the above object, the present invention provides the following means.

  The steel pipe sheet pile cantilever foundation construction method of the present invention is a steel pipe sheet pile canopy foundation construction method in which a plurality of steel pipe sheet piles are placed on the bottom of the water bottom while fitting the joints of adjacent steel pipe sheet piles together. In this case, the scouring state of the ground where the plurality of steel pipe sheet piles are placed is explored, and the ground area where scouring is predicted is improved in advance, and the scouring recess in the area where scouring occurs, At least one of the measures of disposing a grout leakage prevention material so as to cover the steel pipe sheet pile exposed by the above is taken.

  Moreover, in the construction method of the steel pipe sheet pile well foundation of the present invention, the grout leakage preventing material is configured by filling a box or bag with a filling material, and the grout leakage preventing material is disposed in the scouring recess. It is desirable to arrange a plurality of them.

  In the construction method of the steel pipe sheet pile well foundation of the present invention, the condition of the outer periphery ground is confirmed by ultrasonic survey etc. before filling the mortar inside the joint, and measures according to the size of the scouring can be put in the steel pipe sheet pile. By taking measures as needed from the completed location, delay to the process can be suppressed.

  In addition to ensuring mortar fillability, it is also effective in scouring prevention measures, so the design ground surface can be secured.

  Therefore, according to the construction method of the steel pipe sheet pile cantilever foundation of the present invention, it becomes possible to suitably fill the mortar inside the joint connecting adjacent steel pipe sheet piles, making it possible to construct a steel pipe sheet pile well foundation. Become.

It is a figure which shows the construction method of the steel pipe sheet pile well foundation in one Embodiment of this invention. It is a figure which shows the construction method of the steel pipe sheet pile well foundation in one Embodiment of this invention. (A) is a top view which shows a steel pipe sheet pile well foundation, (b) is a figure which shows the state which the grout material leaked from the joint of the part in which scouring occurred while it is a longitudinal section which shows a steel pipe sheet pile well foundation Yes, (c) is an enlarged view of the S part of (a), showing the state in which the grout material has leaked from the joint where the scouring has occurred.

  Hereinafter, with reference to FIG.1 and FIG.2 (FIG. 3), the construction method of the steel pipe sheet pile well foundation which concerns on one Embodiment of this invention is demonstrated.

  As shown in FIG. 1 (and FIG. 3), the present embodiment is used as a foundation for a large bridge on a river or the sea, and a plurality of steel pipe sheet piles 1 are fitted while fitting joints 2 of adjacent steel pipe sheet piles 1 together. The present invention relates to a construction method of a steel pipe sheet pile well foundation A which is placed on a ground G board at the bottom of the water and combined in a closed shape.

  In the construction method of the steel pipe sheet pile well foundation A of the present embodiment, first, a plurality of steel pipe sheet piles 1 are continuously arranged side by side so as to be placed in the underwater ground G and to form an annular space. At this time, the joint 2 is fitted, and a plurality of steel pipe sheet piles 1 are installed while connecting adjacent steel pipe sheet piles 1 to each other.

  Furthermore, while the inside of the joint 2 which connects adjacent steel pipe sheet piles 1 is wash | cleaned, earth and sand etc. are removed, and the mortar (grouting material P) is filled in the joint 2, and watertightness is ensured. At this time, the joint portion above the ground surface (water bottom surface) G1 is filled with mortar while preventing leakage using a grout jacket, and the joint portion below the ground surface G1 uses the ground G as a substitute for the formwork. Fill with mortar.

  Next, underwater concrete is constructed at the bottom of the internal space formed by juxtaposing a plurality of steel pipe sheet piles 1 to construct the bottom base concrete, and the water in the well is drained.

  And a frame is constructed while ensuring a dry environment inside a steel pipe sheet pile well that functions as a temporary cutoff under the surface of the water.

  On the other hand, if scouring occurs in the surrounding ground G of the steel pipe sheet pile well foundation A, the ground G as a substitute for the formwork disappears, and there is a risk of leakage when the joint 2 is filled with mortar. In addition, although the part where the scouring has occurred in the ground G may be filled with mortar using a grout jacket, the scouring may occur locally or suddenly, and cannot be handled by changing to the grout jacket. There are many cases.

  On the other hand, in the construction method of the steel pipe sheet pile canopy foundation A of this embodiment, as shown in FIG. 1, the ground G where scouring is expected is improved in advance by a chemical injection method, a high-pressure injection method, etc. As shown in FIG. 2, a grout leakage prevention material 4 is installed in the scouring recess M of the ground G so as to cover the joint 2 of the steel sheet pile 1 exposed by scouring. Then, a measure that replaces the formwork is selectively used.

  In addition, the grout leakage prevention material 4 is installed and used as a substitute for the formwork. The grout leakage prevention material 4 is filled with a filling material inside a box or bag (for example, a ton pack or a filter unit). It is preferable that a plurality of the grout leakage preventing materials 4 are stacked and disposed in the scouring recess M.

At this time, in this embodiment, after finishing the steel pipe sheet pile driving, the scouring condition of the outer peripheral ground G is investigated / confirmed by ultrasonic exploration or the like. I do.
If the scouring is already large, a grout leakage prevention material 4 such as a ton pack as a substitute for the ground G is installed as a leakage prevention.

  Therefore, in the construction method of the steel pipe sheet pile canopy foundation A of this embodiment, the state of the outer peripheral ground G is investigated / confirmed by ultrasonic exploration before filling the mortar, and measures are taken according to the size of the scour. By taking measures from time to time from the point where the placement of the process has been completed, delay to the process can be suppressed.

  In addition to ensuring mortar fillability, it is also effective in scouring prevention measures, so the design ground surface can be secured.

  Therefore, according to the construction method of the steel pipe sheet pile canopy foundation A of the present embodiment, the inside of the joint 2 connecting adjacent steel pipe sheet piles 1 can be suitably filled with mortar.

  As mentioned above, although one Embodiment of the construction method of the steel pipe sheet pile well foundation based on this invention was described, this invention is not limited to said one Embodiment, It can change suitably in the range which does not deviate from the meaning. .

DESCRIPTION OF SYMBOLS 1 Steel pipe sheet pile 2 Joint 3 Ground improvement part 4 Grout leak prevention material A Steel pipe sheet pile well foundation G Ground G1 Water bottom M Scouring recessed part P Mortar (grouting material)

Claims (2)

In the construction method of the steel pipe sheet pile well foundation, which is formed by combining multiple steel pipe sheet piles on the bottom of the water bottom while fitting the joints of adjacent steel pipe sheet piles together,
Exploring the scouring condition of the ground where the plurality of steel pipe sheet piles are laid, measures to advance the ground area where scouring is predicted, and the scouring recess in the area where scouring occurs, exposed by scouring A construction method for a steel pipe sheet pile well foundation characterized by taking at least one of the measures for disposing a grout leakage preventing material so as to cover the joint. In the construction method of the steel pipe sheet pile well foundation according to claim 1,
The steel pipe sheet pile foundation is characterized in that the grout leakage preventing material is configured by filling a box or bag body with a filler, and a plurality of the grout leakage preventing materials are stacked in the scouring recess. Construction method.

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