JPH10121463A - Steel pipe concrete well foundation set on slant land and its construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a well foundation set on a slant land where a proportion of temporary work quantity to occupy to occupy in overall work is reduced and its construction method by narrowing a working space, eliminating retaining construction and reducing excavated sediment quantity, etc. SOLUTION: This steel pipe concrete well foundation and its construction method are about a pier foundation to be set on a slant land 17, and a steel made well 24 is constructed as a wall body by inserting steel pipes 20 with couplers in a large number of excavated vertical holes 18 arranged and excavated in a circular or square shape, filling a mortar or concrete grout material 30 in their periphery and connecting the couplers of the steel pipes 20 with the couplers with each other by intermediate coupler members. A top end height 23 of this well body is made a retaining wall 36 by making a valley side of the slant land a foundation top end height 33b and making a crest side of the sland land a height stop top end height 33a against slant earth pressure. Top plate concrete 26a making a foundation top plate 26 is filled in an excavated part where sediment in the upper pier is excavated from a lower end 37 of the foundation top plate 26 to be constituted in the well body, and this top plate concrete 26a and a combined reinforcement 38 are firmly combined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a well foundation installed on a slope for a pier foundation, for example, and a method of constructing the same.

[0002]

2. Description of the Related Art Conventionally, as a method of constructing a large-diameter foundation installed on a slope, a hole is generally excavated by manpower or a machine while protecting a hole wall with earth retaining material. There is a deep foundation method of placing concrete.
As an advantage of the deep foundation method, large drilling equipment and driving equipment are not required in spite of installing large-diameter piles, so construction on slopes such as mountainous areas is also possible.

FIGS. 15 and 16 show a vertical sectional view and a plan view of a conventional deep foundation. As shown in each figure, when the deep foundation work is performed on the slope, the slope ground 1 is leveled to secure the work space 2, and then the mountain side 3 and the side 4
An earth retaining wall 6 made of a steel sheet pile 5 or the like is installed in the vehicle. Thereafter, excavation of the entire cross section of the diameter of the vertical hole 7 (about 3 to 15 m) for constructing a foundation inside the earth retaining wall 6 is performed by a human power or an excavator 8 to a predetermined depth (about 10 to 30 m). Do
An earth retaining lining by a segment 10 is formed on an upper side of the hole wall of the vertical hole 7 with excavation.

[0004]

According to the conventional method of excavating a pit by a deep foundation work, as described above, a pit 7 having a predetermined diameter is excavated to a predetermined depth at a time, as shown in FIG. The storage space 11 for the hole wall protection segment 10, the storage space 12 for the rebar for the deep foundation work, the equipment storage space 15, the work space 14 for installing the crawler crane 13 and the like are arranged around the pit 7 for excavating. . 9 is a dump truck, and 16 is a temporary house.

[0005] For the reasons described above, the amount of excavated earth and sand in the vertical hole 7 and the amount of earth and sand for leveling to secure a work space outside the hole are extremely large, and the work is required to level the slope land to secure the work space. It is necessary to install the retaining wall 6 described above, and to cut the slope into a gentle slope of 45 ° or less over a wide area including the periphery of the shaft 7, thereby reducing the amount of temporary construction work. There was a problem that the proportion of the total construction volume was large.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a well base and a method for constructing the same which are installed on a slope with a minimum amount of temporary construction work.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a steel pipe concrete well pipe foundation installed on a slope according to the present invention is a well pipe foundation installed on a slope, and is arranged in a circle or a square. Insert a steel pipe with a joint into a number of excavated holes, fill grout material of mortar or concrete around it, and connect the joints of the steel pipe with a joint with a joint material to construct a well body as a wall body Then, the top end height of the well body, the lower side of the slope as the base top height, the upper side of the slope as a high stop ceiling against the slope earth pressure, and this as a retaining wall, in the well body Excavating the earth and sand in the well above the bottom from the lower end of the foundation top plate to be constructed and filling the excavated part with top plate concrete forming the foundation top plate,
It is characterized in that the top plate concrete and the binder provided on the well body are firmly connected.

Further, in the method for constructing a steel tubular concrete well tube foundation according to the present invention, a crane is arranged in a work space in which a slope is leveled to make it flat, and the crane is placed on a flat ground on the upper side of the work space. The excavator suspended by installing in, excavating a plurality of pits to form a circular or square well cylinder side by penetrating the upper side of the slope with this excavator,
A steel pipe with a joint is erected in each of the well-side pits to form a high ceiling height, and the surrounding area is grouted to form an earth retaining wall, and then penetrate the lower side of the slope ground. Excavating a plurality of pits forming the circular or square well tube side valley side, building a steel pipe with a joint in each of the lower side pits, grouting the periphery thereof, and inside the joint part of the steel pipe with a joint. By excavating the joints and connecting the joints with intermediate joints, and grouting the intermediate joints to form a steel well, and excavating the upper part of the well to construct a foundation top plate I do.

According to the present invention, among the steel pipes with joints inserted into a large number of pits excavated side by side in a circular or square shape on a slope, the height of the steel pipe with joints inserted into the pit on the mountain side is increased. The top of the well is used as the retaining wall, and the well is used as a retaining wall to construct a well body.The upper part of the well body is excavated to construct the foundation top plate, so the crane for hanging the excavator is placed inside the well body. By doing so, the working space can be narrowed.

In other words, according to the present invention, in excavation on a slope, a space for installing a full-rotation type excavator and a space for installing a crawler crane only need to be secured, and each space does not need to be at the same height position. Therefore, it is not necessary to make the flat ground of all the Izutsu foundations that are adjusted to the lowest height. The work space required for the construction of the Izutsu foundation is reduced by reducing the volume.

Further, according to the present invention, the valley side of the slope can be created by using the continuous wall of the steel pipe with the joint having the ceiling top installed on the mountain side of the slope as the earth retaining wall.
For example, in the present invention shown in FIGS. 1 to 14, the amount of soil to be moved to leveling to secure a work space is reduced as compared with the conventional example shown in FIGS. 15 and 16. In other words, when constructing an Izutsu foundation with the same outer diameter on a slope with the same slope, FIG.
In the conventional example shown in FIG. 16 and FIG. 16, the dimension L in the inclined direction of the working space is 35 m and the dimension W in the lateral direction is 30 m. On the other hand, in the present invention, as shown in FIG. dimension L ₁ of the inclined direction 18m, dimension W ₁ in the transverse direction is 20 m. The two are compared and expressed by a mathematical formula: 20/30 × 18/35 × (18 tan30 / 35 tan3
0) = 18%, and the present invention requires only 18% of the movement amount of the conventional leveling, and furthermore, the work space area is reduced by about 50%. In addition, the amount of excavated soil can be reduced to about 35% of the conventional amount.

Further, since the earth retaining wall is deeply embedded and has a large sectional rigidity of the steel pipe, the earth retaining wall has a sufficient resistance against earth pressure, and does not require a support work, an upset, a stay, and the like.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show an installation state of a steel pipe concrete well pipe foundation installed on a slope 17 by the method of the present invention, and a steel well pipe 24 constituting the well pipe foundation.
Is inserted through the slope ground 17 to a predetermined depth of the ground in the ground 25, and the depth of the deep ground is determined when the upper ground on the upper side of the installation position of the steel well tube 24, that is, the mountain side 35 slides. The depth is set to a sufficient rooting force so that the well tube does not tilt in the sliding direction due to the acting horizontal force. Further, a lower end portion of a concrete pier 27 is integrally formed with a foundation top plate 26 cast at an upper portion in a steel well tube 24. For example, a road bridge 29 is erected above the concrete pier 27 via a plurality of bridges 28 made of H-shaped steel.

The structure of the steel well 24 will be further described. A large number of pits 18 are excavated through the slope 17 so as to be arranged in a circle at regular intervals, and a steel pipe 20 with a joint is inserted into each pit 18. And the jointed steel pipe 20
Is disposed so as to be located in the circumferential direction of the planned construction position of the well pipe, and a hardening grout material 30 such as mortar or concrete is provided between the hole wall of the vertical hole 18 and the steel pipe 20 with the joint. Is filled.
In addition, as shown in an enlarged view in FIG. 3, the adjacent pits 18 are skipped by one element as a preliminary erection to prevent the excavation pits from bending, and then the overlapped excavation is performed at the intermediate portion to form a continuous column 31. After being built, opposed slit pipe joints 22 in adjacent jointed steel pipes 20
In the meantime, an intermediate hole 32 is formed to form a space, and the grout material in the slit pipe joint 22 is excavated and removed, or a lid is previously attached to the slit portion, and the slit pipe joint is formed. The grout into the interior 22 is prevented and the lid is removed when the intermediate hole 32 is drilled. Next, after inserting the intermediate joint member 23 over each slit pipe joint 22, a hardening grout material is injected and filled into the intermediate hole 32 and the slit pipe joint 22.

Further, as a characteristic configuration of the embodiment of the present invention, the top height 33 of the steel well tube 24 is set to the valley side 3 of the slope ground 17.
4 is defined as a base crown height 33b, and the mountain side 35 of the slope ground 17 is defined as a high stop crown height 33a against slope earth pressure. The upper part is a retaining wall 36. Further, the earth and sand in the well above the base plate 26 to be constructed in the steel well 24 is excavated from the lower end 37 of the base well 26, and the excavated portion is filled with the top plate concrete 26a and cast. The base top plate 26 is firmly connected to a connecting bar (dive) 38 protruding from the main body 21.

Next, an example of carrying out the method of the present invention to build a steel tube concrete well foundation on a slope will be described. First,
As shown in FIGS. 5 and 6, in order to install a below-described all-turn type excavator 19 for the construction of the mountain side 35 on the slope ground 17,
And, for installation of the crawler crane 13 described below,
First and second work spaces 39 and 40 are provided in the mountain side 35 and the valley side 34 of the sloped land 17 in a stepwise manner by step cutting, and a horizontal land 41 is provided as necessary. That is, the first
And the second work spaces 39 and 40 are a work space for installing the full-rotation type excavator 19 and a work space for installing the crawler crane 16, respectively. Work spaces need not be at the same height.

Therefore, it is not necessary to make the ground on which the entire well of the well is to be built on a flat ground in accordance with the lowest height position among the portions of the slope ground 17 where the well is to be built. The first, upper and lower two steps such as step cutting
The second working spaces 39 and 40 can be sufficiently prepared by forming the second working spaces 39 and 40, and do not require earth retaining work as in the case of making a flat space with a large space for the entire well tube foundation, and reduce the amount of soil leveled. (The specific figures for reduction of excavated soil volume are described above).

Next, as shown in FIGS. 7 and 8, the crawler crane 13 is installed in the second work space 40, and the full-rotation type excavator 19 is installed in the first work space 39. The full-turn type excavator 19 is suspended by a suspension rope 41 of the crawler crane 13 via a crown 42. The excavator 19 excavates the pit 18. In the figure, reference numeral 44 denotes a club hammer. The pit 18 at this time
As shown in FIG. 8, a plurality of excavations are made on the circumferential line (C) constituting the plane circular well cylinder and over a predetermined angle range of the mountain side 35.

At this time, the construction order of the vertical hole 18 is as shown in FIG. 8, and the figure shown by the symbol a shows the figure in which the steel pipe 20 with the joint is completely installed in the vertical hole 18, and the figure shown by the symbol B is The preceding laying planned position is shown, and the figure indicated by the symbol C indicates the lap laying planned position.

When excavating the vertical hole 18, the vertical hole 2 is formed in the ground of the slope ground 17 by using an excavation method that does not use muddy water, for example, an excavator with a casing. If the excavation method using muddy water is adopted in the sloping ground 17 where the ground is fragile, the water that escapes from the hole may accumulate on the slope and induce a landslide. Is preferred.

Then, as shown in FIGS. 9 and 10, the pit 1 extends over a predetermined angular range on the mountain side 35 at the position where the well is to be constructed.
A vertical hole 18 to be erected in advance is excavated at intervals corresponding to this, and a steel pipe 20 with a joint is inserted into the vertical hole 18 and then hardened between the hole wall of the vertical hole 18 and the steel pipe 20 with a joint. The grout material 30 is injected and filled. Next, a pit 18 to be wrapped is excavated in the middle of the pit 18 to be preceded, and a steel pipe 20 with a joint is inserted into the pit 18 in the same manner as described above.
Then, the hardening grout material 30 is injected and filled between the hole wall of the vertical hole 18 and the steel pipe 20 with the joint.

Next, the hardening grout material 30 in the slit pipe joint 22 on the opposite side of the adjacent steel pipe 20 with a joint is connected to a rotary impact tool having a cross bit (FIG. 1).
Drilling with the percussion drill 45) shown in 1
The inside of the slit pipe joint 22 is defined as a space. (Also, as described above, attach the lid along the slit,
There is also a method of preventing penetration of the curable grout material 30. Then, the lid may be broken by the guide member. Next, an adjacent slit pipe joint 22 is inserted by an excavator having a guide member inserted into the slit pipe joint 22 on the opposite side of the adjacent jointed steel pipe 20.
A space is formed by drilling an intermediate hole 32 that is close to and adjacent to the vertical hole 18 and forms a space.
After the flange-side portion of the intermediate joint member 23 made of I-shaped steel is inserted into each of the slit pipe joints 22, the inside of the intermediate hole 32 and the slit pipe joint 22 are inserted.
The curable grout material inside is filled and filled (see FIG. 3). Through the above-mentioned construction work, as shown in FIG.
Of the steel pipe continuous wall with a joint having a high end and a top end height of 33b, and the upper part thereof is used as a retaining wall 36.
A work space for the construction of the valley-side well body will be secured inside the building.

Next, as shown in FIG. 11 and FIG.
Construction of a steel well tube on the valley side over the predetermined angle of 4 is performed. The crown height 33 of the valley-side steel well is a base crown height 33a, and is provided at a position lower than the high stop crown height 33b constituting the retaining wall 36.

In this manner, as shown in FIGS. 11 and 12, the crawler crane 13 and the full-rotation type excavator 19 suspended from the crawler crane 13 on the sloped land 17 allow the base crown height 33a to be increased.
Then, a steel well 24 made of a steel pipe 20 with a joint having a high stop 33b is built. If the length of the steel pipe 20 with one joint is shorter than the length of the well tube to be built, the steel pipe 20 with the joint is inserted into the pit while being welded together, and then the wall of the pit 18 and the joint are connected. Steel pipe 20
Is filled with a curable grout material 30 to fill the column 31
To build.

Next, as shown in FIGS. 13 and 14, the upper part of the steel well 24 is excavated to a predetermined depth L using the excavator 43, and the steel pipe 20 with the joint exposed to the inside of the well after excavation is excavated. Then, a plurality of connecting bars 38 are welded to the surface of the excavated portion (see FIG. 4).
To form a base top plate 26 by integrating with the steel pipe 20 with a joint. Thereafter, a concrete pier 27 is constructed on the foundation top plate 26 via a reinforcing bar (not shown) planted on the foundation top plate 26. In addition, after Izutsu foundation construction,
The jointed steel pipe 20 used as the earth retaining wall 36 of the steel well tube 24 may be cut. Moreover, the connection structure between the steel pipes 20 with joints may use another known method.

[0026]

As described above, according to the present invention, the following effects can be obtained. In the present invention, small-diameter steel pipe piles are sequentially built in a pit, and a well is constructed for each element. The upper part in the constructed well is an available area. Until the end, it can be used without excavation, and cranes can be installed there. Along with this, it is only necessary to secure a narrow plane space for installing small diameter steel pipe piles, and it is not necessary to level the entire outer diameter of the well base, so leveling of slopes may be stepped, Excavation volume is small. Therefore, in combination with the above, there is an effect that the excavated soil amount is small, the surrounding environment is not impaired, and the influence on the natural environment in the mountainous area is small in a narrow work space. In addition, since the valley side is constructed with steel pipes with joints installed on the mountain side as self-supporting retaining walls, new retaining walls are not required, and the ratio of temporary construction work to the total work volume can be reduced. This has the effect of quickly building the foundation.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing an installation state of a steel pipe well foundation installed on a slope.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 1;

FIG. 5 is an explanatory side view of a first operation step for implementing the method for constructing a steel pipe well foundation according to the present invention on a slope.

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is an explanatory side view of the second operation step.

FIG. 8 is a plan view of FIG. 7;

FIG. 9 is an explanatory side view of the third operation step.

FIG. 10 is a plan view of FIG. 9;

FIG. 11 is an explanatory side view of the fourth operation step.

FIG. 12 is a plan view of FIG.

FIG. 13 is an explanatory side view of the fifth working step.

FIG. 14 is a plan view of FIG.

FIG. 15 is a vertical cross-sectional view showing a state of excavation of a pit on a slope by a conventional deep foundation method.

FIG. 16 is a plan view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slope 2 Work space 3 Mountain side 4 Side 5 Steel sheet pile 6 Retaining wall 7 Vertical hole 8 Excavator 9 Dump truck 10 Segment 11 Segment storage 12 Reinforcement storage 13 Crawler crane 14 Work space 15 Equipment storage 16 Temporary house 17 Slope Reference Signs List 18 vertical hole 19 full-turn excavator 20 steel pipe with joint 21 steel pipe main body 22 slit pipe joint 23 intermediate joint member 24 steel well tube 25 ground 26 foundation top plate 26a top plate concrete 27 bridge pier 28 bridge 29 road bridge 30 grout material 31 pillar body 32 Intermediate hole 33 Top end height 33a High stop top end height 33b Base top end height 34 Valley side 35 Mountain side 36 Earth retaining wall 37 Lower end 38 Joining bar 39 First work space 40 Second work space 41 Hanging rope 42 Crown 43 Excavator 44 Club Hammer 45 Over cut Deployment drill

Claims (2)

[Claims] Claims: 1. A well foundation installed on a slope,
A steel pipe with a joint is inserted into a large number of drilled holes drilled side by side in a circle or a square, grout material of mortar or concrete is filled around the pipe, and the joints of the steel pipe with a joint are connected to each other with a joint material. The top of this well is set as the top of the well, and the lower side of the slope is taken as the base height.
The upper side of the slope is a high stop ceiling against the earth pressure of the slope and this is used as a retaining wall, and the earth and sand in the well above the bottom is excavated from the lower end of the foundation top plate to be formed in the well and the excavated portion is formed. A well foundation installed on a slope, characterized in that the top concrete forming the foundation top plate is filled and the top concrete is firmly bonded to a binder provided on the well body. 2. A crane is provided in a work space where the slope is leveled to be flat, and an excavator suspended by the crane is installed on a flat ground on the upper side of the work space. Excavating a plurality of pits that form a circular or square well cylinder side by penetrating the upper side of the sloped land with a joint so as to remain high in each of the pits on the upper side and form a top end height A steel pipe is erected, grouted around it to form a retaining wall, and then excavated a plurality of pits that penetrate the lower side of the sloped land and form the circular or square well tube valley side portion. A steel pipe with a joint is erected in each of the lower pits, the periphery thereof is grouted, the inside of the joint part of the steel pipe with the joint is excavated, the joint parts are connected with an intermediate joint material, and the intermediate joint material is formed. The well is constructed by grouting, and the upper part of this steel well is excavated. A method of constructing a well foundation installed on a slope characterized by constructing a foundation top plate.