JP2001288753A - Press-in open caisson method making use of press jack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press-in open caisson method making use of versatile press jacks. SOLUTION: A vertical tension bar is mounted to a part on the ground of an undeground anchor placed in the ground of the outside of a hollow cylindrical caisson, a reaction force base for getting press-in reaction force is placed on the tension bar, a plurality of press jacks are set in a vertical posture between the upper end face of the caisson and reaction force base, and the caisson is directly and vertically pressed in the ground by driving of the press jacks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-fitting open caisson method in which a hollow cylindrical caisson previously manufactured on the ground is forcibly pressed vertically into the ground by a press-fitting jack while excavating and discharging the inside. It belongs to the technical field, and particularly relates to a press-fit open caisson method using a general-purpose press jack.

[0002]

2. Description of the Related Art Conventionally, a hollow cylindrical caisson is used as a means for supporting a viaduct of a viaduct or an elevated road and constructing a foundation for transmitting a load of a superstructure to the ground, while excavating and discharging the inside of the hollow caisson. The caisson method of forcibly pressing vertically into the ground to reach the support layer is known and widely practiced.

The caisson method is roughly classified into a pneumatic caisson method using air and an open caisson method using underwater excavation.

The resistance of the caisson to press-fitting includes the penetration resistance of the cutting edge, the frictional resistance of the outer periphery of the caisson, and the buoyancy due to groundwater and the like. If the caisson does not sink by its own weight, a method of applying a load by weighting steel, etc., or a method of installing a ground anchor in the ground at the outer peripheral position of the caisson and applying a load with a jack as a reaction force and pressing it in Etc. are known. The press-fitting open caisson method of the present invention belongs to the latter method.

In a conventional general press-fitting method, as shown in a conceptual diagram in FIG. 9, a tension bar 2 is vertically mounted on a ground portion of an underground anchor 1 and a center hole jack 3 for applying a reaction force to the tension bar 2 is used. And a load transmitting member 6 is installed between the gantry 4 to which the center hole jack 3 pushes downward and the upper end surface of the caisson 5, and indirectly transmits the output (load) of the center hole jack 3 to the caisson 5. And press-fitted.

[0006]

The conventional press-fitting open caisson method shown in FIG. 9 uses a center hole jack 3. The center hole jack is used for a press jack used in a shield method or the like. There is a disadvantage that it is somewhat expensive because it lacks versatility in comparison.

In addition, the center hole jack 3 takes a lot of time and labor to change the arrangement after the caisson 5 of one lot has penetrated, and the output (load) of the center hole jack 3
Is indirectly transmitted to the caisson 5 to perform press-fitting, so that there is a problem that it is difficult to control the press-fitting accuracy (vertical accuracy) and attitude of the caisson 5.

Therefore, an object of the present invention is to use a versatile and relatively inexpensive press jack as a press-fitting jack, and to apply a press-fitting load directly to the caisson. An object of the present invention is to provide a press-fitting open caisson method using a press jack, which is improved so that (tilt, displacement) and attitude control can be easily performed.

[0009]

As a means for solving the above-mentioned problems, a press-fitting open caisson method using a press jack according to the first aspect of the present invention comprises a hollow cylindrical caisson having a hollow cylindrical caisson. In a press-fitting open caisson construction method in which excavation and forcible insertion into the ground vertically with a press-fitting jack while excavating, a vertical tension bar is attached to the ground portion of the underground anchor installed in the ground outside the caisson, A reaction table for taking a reaction force of press-fitting is installed in the tension bar, a plurality of press jacks are installed in a vertical position between the upper end surface of the caisson and the reaction table, and the caisson is directly grounded by driving the press jack. It is characterized by being vertically pressed into the inside.

According to a second aspect of the present invention, in the press-fitting open caisson method using the press jack according to the first aspect, a plurality of inclinometers are installed in two horizontal directions of the caisson, and the measured values are transmitted to the control panel. Inputting, installing a plurality of press jacks in the circumferential direction of the caisson, performing drive control on the control panel, disposing a spreader between the press jack and the upper end surface of the caisson, the press jack and the spreader are free By connecting with a joint, the press jack is driven through the control panel based on the measured value of the inclinometer, and the caisson is vertically pressed into the ground by automatic control or manual control that keeps the upper end of the caisson horizontal. I do.

According to a third aspect of the present invention, in the press-fitting open caisson method using the press jack according to the first aspect, a downward reaction force receiver is provided on the tension bar at a constant pitch, and the tension plate is provided on the reaction force table. Go down the bar,
A self-aligning holder that automatically takes a reaction force to the reaction force receiver by an automatic centering action and a gravitational action is provided, and the automatic rearrangement is performed according to the contraction operation of the press jack.

[0012]

FIG. 1 conceptually shows an embodiment of a press-fitting open caisson method using a press jack according to the first to third aspects of the present invention.

The hollow cylindrical caisson 5 is pressed directly by the press jack 10 and forcedly pressed into the ground vertically while excavating and discharging the inside of the caisson 5 with a clamshell bucket (not shown). The press jack 10 is mounted below the reaction table 4 via a support frame 14. The output of the press jack 10 takes a reaction force on the reaction force table 4 and is transmitted directly to the caisson 5 through the spreader 15. The press jack 10 is used for a usual shield method, has versatility, and can be obtained at low cost. The caisson 5 is made of reinforced concrete as an example and has an outer diameter of 6
m, a hollow cylindrical shape having an inner diameter of about 4.5 m, and a length of about 5 m or more in the axial direction.

When press-fitting for one lot of the caisson 5 is completed, the press jack 10 is moved to the support frame 14,
And with the spreader 15 once. And
The main bar 13 is stretched for binding, concrete is cast and joined to the next upper caisson, and the upper and lower caissons are integrated and sequentially press-fitted.

A specific embodiment thereof is shown in FIGS.

At the position outside the caisson 5 and corresponding to the four corners of the rectangle in FIG. 4 which approximately overlaps the circular caisson 5, the underground anchor 1 is installed vertically and deep enough into the ground. A vertical tension bar 2 is attached.

The reaction bar (main girder) 4, 4 for taking a press-fit reaction force by the self-aligning holder 11 is installed on the tension bar 2. That is, one reaction force table 4
It is installed so that both ends are supported by two right and left tension bars 2, 2. The two reaction tables 4, 4 are respectively superposed on the circular caisson 5 with an equal overlapping margin, and are arranged in parallel. As shown in FIG. 6, each reaction table 4 has a hollow box-shaped cross-sectional structure to reduce the weight. The two reaction tables 4 are mutually connected by a connecting member 17 and integrated.

A support frame 14 in the form of a polygonal ring is attached under the two reaction bases 4 and 4 and overlaps the upper end surface of the circular caisson 5 as a whole. The cylinder head of the jack 10 is fixed and installed in a vertically downward posture. The spreader 15 mounted on the upper end face of the caisson 5 and the rod of each press jack 10 are connected by a universal joint 16. Therefore, press jack 10 and caisson 5
Even if the relationship with the upper end surface is not vertical and the inclination is slightly larger or smaller, the press-fitting can be performed without any trouble. Spreader 1
Numeral 5 is for evenly distributing the load of each press jack 10, and is placed on the upper end surface of the caisson 5 avoiding the arrangement of the main reinforcement 13, as shown in FIG.

The arrangement of the plurality of press jacks 10 will be further described.

4 and 5, the press jacks 10 each of which is a set of four are arranged side by side in an arrangement close to each other for each set, and the press-fit jacks 10 of each set are two reaction forces. It is installed at four positions just below the stands 4, 4, with the upper end surfaces of the circular caisson 5 being substantially equally distributed. That is, each set of press jacks 10
A reaction force is applied to the reaction force table 4 immediately above, and the caisson 5 immediately below is directly pressed and pressed. Moreover, since the arrangement is on a horizontal secondary plane (X, Y plane), by driving all the press jacks 10 at the same time, the entire circumference of the caisson 5 can be evenly vertically pressed into the ground. If necessary, any group of press jacks is stopped, and the press jack group at the opposite position is driven, so that only a portion of the caisson 5 is press-fitted preferentially, and the inclination of the caisson is reduced. Adjustment of displacement and control of posture can be performed.

For this reason, as shown in FIG. 4, a total of four inclinometers 18 are installed at quadrant (horizontal X-axis and Y-axis directions) positions on the upper end surface of the circular caisson 5, and the measured values are measured. Is input to the control panel 19. The control panel 19 uses a personal computer. The control panel 19 is also supplied with a measurement value of a sensor 20 for measuring a rod speed and a stroke of each press jack 10, a measurement value of an encoder 21 for continuously measuring the press-fit depth (press-fit amount) of the caisson 5, and the like. .

The operation of each press jack 10 is executed as shown in the flowchart of FIG. The operation is automatically or manually controlled through the control panel 19 in the operation room.

That is, when the X-axis inclinometer 18x installed on the orthogonal X and Y axes on the caisson 5 has a positive value and the Y-axis inclinometer 18y has a negative value, the presses labeled in FIG. This is a state in which the jack has been press-fitted, in other words, a state in which the caisson is inclined in the direction of.
Therefore, in the case of automatic operation, automatic control is started at the stage when the inclination exceeds the set amount of inclination, and the press jack performs the following operation (operation of following the sinking of the caisson 5 without pushing force). Become. On the other hand, the press jack continues the pressurizing operation. As a result, when the inclination amount recovers to the set value (allowable value), all the press jacks shift to the pressurizing operation again. When the press jack 10 is near the maximum stroke (for example, 1000
mm), all the press jacks 10 are automatically stopped, and the process shifts to a refilling process.

Next, the self-aligning holder 11 in which the reaction table 4 applies a reaction force to the tension bar 2 will be described.

First, as shown in each figure, the tension bar 2 is provided with a reaction force receiving member having a construction in which a downward reaction force can be obtained by reinforcing the upper side of the flange with a conical reinforcing material 2b at a constant pitch in the vertical direction. 2a are provided over the entire length. On the other hand, the tension bar 2 is transmitted to the upper end of the hole 4a through which the tension bar 2 penetrates in the vertical direction in the reaction force table 4 and automatically reacts with the reaction force receiver 2a by the self-centering action and the gravity action. A self-aligning holder 11 for taking a force is provided.

That is, the base ring 11 is provided above the reaction table 4.
b is fixed by welding or the like, and the reaction
a throat portion 11 having a diameter slightly larger than the outer diameter of a
a, a self-aligning action and effect is achieved by the sliding action of the reaction force receiver 2a of the tension bar 2 passing through the throat portion 11a (see FIG. 7B). The throat section 11a
The lower outer side of the hold claw 11d is attached to a bracket 11c protruding outward from the upper side of the bracket 11c by a pin 11e so as to be tiltable.

The holding claw 11d is a steel block obtained by dividing an annular body surrounding the outer periphery of the tension bar 2 into a plurality (for example, four equal parts) in the radial direction.
d is configured to be tiltable about the pin 11e in the radial direction of the tension bar 2. Moreover, since the position of the pin 11e is located considerably outside the position of the center of gravity of the hold claw 11d, each hold claw 11d is always subjected to an inward moment action that falls down toward the tension bar 2.

Accordingly, when the above-described press jack 10 advances the downward pressurizing operation (caisson press-fitting) within the range of its effective stroke, and advances up to one pitch or a plurality of pitches of the reaction force receiver 2a of the tension bar 2, A contraction operation is performed to change the force receiver 2a. At this time, the upper frame such as the reaction table 4 is lowered by its own weight. Along with this, the self-aligning holder 11 having the above configuration first opens outward to a position where each of the holding claws 11d can descend along the outer diameter of the corresponding reaction force receiver 2a of the tension bar 2 as shown in FIG. 7A. We pass without trouble. That is, the hold claw 11d is
During the operation of the contraction stroke of the press-fit jack 10, the press-fit jack 10 passes through the position of each reaction force receiver 2a while repeating rattling and opening and closing operations.

When the press jack 10 reaches the limit of the contraction stroke, as shown in FIGS. 7B and 7C, each of the hold claws 1 released from the restraint by passing through the position of the reaction force receiver 2a.
1d operates so as to equally fall from all directions to the tension bar 2 by the inward moment action, and finally strikes under the reaction force receiver 2a to obtain a reaction force as shown in FIG. 7C. , And achieve the automatic rearrangement. Thereafter, when the press jack 10 resumes the pressing operation of pressing the caisson 5 downward, the relationship between the hold claw 11d, the tension bar 2, and the reaction force receiver 2a becomes more complete, and the reaction force of the caisson press-fitting is reduced. Secured.

[0030]

[Effects of the present invention] The press-fitting open caisson method using the press jack according to the first to third aspects of the present invention uses a versatile and inexpensive press jack as the press-fit jack, so that it is easy to obtain. This greatly contributes to a reduction in equipment costs.

In addition, since each press jack directly applies a press-fit load to the caisson, the press-fit accuracy (tilt, displacement) and attitude of the caisson can be easily and reliably controlled as individual control of each press jack, and accuracy and quality can be improved. The excellent press-fitting open caisson method is economical.

[Brief description of the drawings]

FIG. 1 is a partial view conceptually showing an embodiment of a press-fitting open caisson method according to the first aspect of the present invention.

FIG. 2 is an elevation view showing an embodiment of the present invention.

FIG. 3 is a perspective view showing a relationship between a press jack, a caisson, and a support frame.

FIG. 4 is a plan view of FIG. 2;

FIG. 5 is a view taken along line AA of FIG. 2;

FIG. 6 is a side view of FIG. 2;

FIGS. 7A to 7C are explanatory diagrams of the operation of the self-aligning holder.

FIG. 8 is a flowchart of control.

FIG. 9 is a partial view conceptually showing an embodiment of a conventional press-fit open caisson method.

[Explanation of symbols]

 5 Caisson 10 Press jack 1 Underground anchor 2 Tension bar 4 Reaction table 18 Inclinometer 19 Control panel 15 Spreader 16 Universal joint 11 Self-aligning holder

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 000105497 Kokudo Koki Co., Ltd. 4036-1 Nakatsu, Aikawa-cho, Aiko-gun, Kanagawa (72) Inventor Yukio Kitamura 1-18-22 Nishiki, Naka-ku, Nagoya-shi, Aichi Prefecture (72) Inventor Satoshi Kamiya 1-18-18 Nishiki, Naka-ku, Nagoya City, Aichi Prefecture Incorporated Company Takenaka Civil Engineering Nagoya Branch (72) No. 18-22, Takenaka Civil Engineering Nagoya Branch (72) Inventor Tsuguo Yamamoto 18-18, Nishiki, Naka-ku, Nagoya-shi, Aichi Prefecture No. 18-22 Takenaka Civil Engineering Nagoya Branch (72) Inventor Katsumi Inayoshi Aichi 1-18-18 Nishiki, Naka-ku, Nagoya-shi, Japan Inside Takenaka Civil Engineering Nagoya Branch (72) Inventor Shoji Oda 1-19-24 Nishiki, Naka-ku, Nagoya-shi, Aichi Shiraishi Name (72) Inventor Kiyoyoshi Suzuki 66-1 Minagawa, Chichi-shi, Aichi Pref.Hiroshin Construction Co., Ltd. (72) Inventor Teruo Ariga 4036-1 Nakatsu, Aikawa-cho, Aiko-gun, Kanagawa Kokudo Koki Co., Ltd. F-term (reference) 2D046 CA12 DA03

Claims (3)

[Claims] (1) A hollow cylindrical caisson is excavated therein.
In a press-fitting open caisson method of forcibly pressing vertically into the ground with a press-in jack while discharging earth, a vertical tension bar is attached to a ground portion of an underground anchor installed in the ground outside the caisson, A reaction table for taking the reaction force of press-fitting is installed, a plurality of press jacks are installed in a vertical position between the upper end surface of the caisson and the reaction table, and the caisson is directly driven into the ground by driving the press jack. Press-fitting open caisson method using a press jack, characterized by vertical press-fitting. 2. A plurality of inclinometers are installed in two horizontal axis directions of a caisson, and the measured values are input to a control panel. A plurality of press jacks are installed in a circumferential direction of the caisson, and drive control of the control jack is performed by the control panel. A spreader is arranged between the press jack and the upper end surface of the caisson, the press jack and the spreader are connected by a universal joint, and the press jack is driven through the control panel based on the measured value of the inclinometer. 2. The press-fitting open caisson method using a press jack according to claim 1, wherein the caisson is vertically pressed into the ground by automatic control or manual control for keeping the upper end surface of the caisson horizontal. 3. A tension bar is provided with a downward reaction force receiver at a constant pitch, and is transmitted to the reaction force table through the tension bar. The reaction force is automatically applied to the reaction force receiver by an automatic centering action and a gravitational action. 2. The press-fitting open caisson method using a press jack according to claim 1, wherein a self-aligning holder is provided, and automatic re-arrangement is performed in accordance with a contraction operation of the press jack.