JPH0215693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of driving steel pipe piles into hard ground at sea. Conventionally, the method of driving steel pipe piles into the ground, which cannot be driven only by percussive pile driving machines such as normal vibrohammers and diesel pile hammers, is the so-called method of installing steel pipe piles into holes previously excavated with an excavator. Pre-boring method A method in which a device to loosen the ground, such as a high-pressure water jet, is installed at the tip of the pile, and the pile is driven while loosening the ground.The pile is driven to a depth that can be driven with a pile driver, and then a boring machine, etc., is inserted into the steel pipe. , a method was used in which the ground inside the pile was dug further below the tip of the pile, and then the steel pipe pile was driven in again.However, in the method of , a hole larger than the pile was dug, and after the steel pipe was installed, mortar was injected. This requires a lot of time and expense, and there are also problems with the retention of the pore walls when a deposited layer is on top. In addition, it is difficult to apply the method to hard rock, and the hole below the tip of the pile is usually smaller than the diameter of the pile.
It was difficult to drive into hard rock, and the piles could not be integrated with the surrounding ground, so they had the disadvantage that much could not be expected from the pulling force of the piles. None of these methods can be said to be satisfactory, and this tendency is particularly noticeable when the diameter and length of the steel pipe pile increases. time·
It was always difficult. The present invention improves the above-mentioned drawbacks, and uses a rodless hole-expanding excavator with a driving part of the drilling bit installed at the tip to perform excavation at the tip of the pile. This is a steel pipe pile driving method and a pushing device that basically consists of pushing with a pushing device, and reduces the construction period and cost especially for large-diameter long piles where the diameter and length of the steel pipe pile are large. below,
Embodiments of the present invention will be described based on the drawings. FIG. 1 shows an example of a construction method in which a steel pipe pile 2 is driven as a diagonal pile using a ship scaffolding 1. In the case of normal ground in Fig. 1, since it is rare for the ground to start out as hard, first, steel pipe pile 2 is driven into sedimentary layer A with a hammer. Next, after setting the pile pushing device 3 at the bedrock B, the rodless rotary hole expanding type excavator 4 is placed inside the steel pipe pile 2 and excavation is started. At this time, a diameter suitable for expanding the hole is selected according to the bedrock layer B, and after excavation is performed to 2 to 3 times the diameter of the normal pile, the steel pipe pile 2 is pushed downward by the pile pushing device 3 set at the top. This operation is repeated and when a predetermined depth is reached, the excavator 4 is hoisted up and removed. Next, if necessary, final piling is performed using an impact type pile driver (not shown) or the like. Thereafter, a hardening agent such as mortar is injected from the tip of the steel pipe pile 2 to integrate it with the ground.
Fig. 2 shows a rodless rotary hole-expanding excavator 4 used in the present invention, in which a submersible motor 7 is built into the driving device of the excavator bit 6, and a suspension wire 8 of the excavator 4 and a carrier are connected to the upper part. tire cable 9, excavation shear discharge hose 10, braking cable 1
The diameter is the smallest when the center axis 13 of the excavator and the excavator bit axis 12 are closest to each other, and the diameter is the farthest apart. The maximum diameter is when the diameter is 150%. Furthermore, in order to accurately excavate the lower end of the ground from the steel pipe pile 2, even when the pile is inclined, for example, a plurality of guides 14 are provided at the upper drive part of the excavation bit 6, or further above it if necessary. It is arranged along the inner circumference of the steel pipe pile 2. On the ship's scaffolding 1 that holds the excavator 4, equipment such as the excavator body and hoses are hung, a crane 5 for the hoisting place, a cable reel for winding in other cables, a power source, and an excavation shear processing device are installed. will be installed. Next, the pile pushing device 3 of the present invention will be explained. In FIGS. 3 to 5, the mast 15, the boom 16, and the steel pipe tilting cylinders 17 provided on both outer sides of the boom 16 hold the push-in portion 18 vertically or inclinedly.

The pile pushing part 18 is an openable/closable hydraulic chuck 1 with a variable inner diameter that firmly grips the outer periphery of the steel pipe pile 2.
Guide 20 is an opening/closing type with variable inner diameter like 9.
and a steel pipe pushing cylinder 21 rotatably attached to the tip of the boom 16. The driving angle of the steel pipe pile 2 is set using the steel pipe tilting cylinder 17, the steel pipe pile 2 is erected along the opening/closing type hydraulic chuck 19 and the opening/closing type guide 20, and the excavator 4 is set at the tip of the steel pipe pile 2. As the steel pipe is excavated, the steel pipe pushing cylinder 21 is operated,
Continuously push in steel pipe pipe 2. In addition, the openable/closable guide 20 can also be used for holding when adding two steel pipe pipes. The mast 15 is attached to the ship's scaffolding 1, and an appropriate number (in this embodiment, one cylinder is shown) of mast holding cylinders 22 are provided at an angle to the cylinder part of the mast 15, and the mast 15 and the mast holding cylinder 22 are installed at an angle. 22 is provided with an absorbing device such as an accumulator 23, so that the vibration of the ship scaffolding 1 is not transmitted to the pile pushing part 18. An auxiliary cylinder 24 provided in the pile pushing part 18 is used for positioning the steel pipe pile 2 and finely adjusting the angle. The steel pipe pile driving method and the driving device according to the present invention, which have the above-described configuration and construction procedure, have the following advantages.

When a ship is used as a scaffold, the driving device is designed to absorb the rocking motion of the ship, making it possible to excavate and push the pile without transmitting the rocking motion of the ship to the pile, increasing the operating rate of driving the pile. By providing three mast holding cylinders, three-dimensional movement can be absorbed.

Since the excavator is rod-less and the steel pipe piles are pushed in sequentially, it is possible to insert the piles into hard ground continuously without having to hoist the excavator or connect the rods, and the speed is faster than before. It is several times faster than the construction method,
This tendency is particularly noticeable when the length of the steel pipe pile becomes longer.

Since the excavator is rod-less, it is easy to set up and retrieve the excavator.

In addition to the method of setting an excavator at the tip of the pile from the beginning and pushing the pile in with the excavation, there is also the method of setting the excavator at the tip of the pile from the beginning and pushing the pile in as the pile is excavated. The excavator can be set up and the pile tip can be used to expand the hole.

By selecting the Rock Bit excavator, it is possible to easily excavate into bedrock with an unconfined compressive strength of several hundred kg/ ^cm2 , and since it is a hole-expanding type, it can be easily excavated without damaging the tip of the pile. It can be planted to a predetermined depth. This tendency is particularly noticeable as the pile diameter increases.

Because the outer periphery, which is difficult to completely reach the tip of the hole, is hardened into the ground by expanding the hole, it can withstand not only the pushing force that acts on the pile but also the pulling force.

A similar effect exists for diagonal gages.

It is obvious that the present invention, which has the above-mentioned advantages, is most advantageous especially in the construction of large diameter, long and diagonal jackets, which are expected to increase in number in the jacket installation work for offshore oil and gas drilling. As the work scaffold according to the present invention, when on water, a pier,
Fixed scaffolding such as jackets, or pontoons,
Floating scaffolding for ships, etc. is required, and floating scaffolding is advantageous because the piling device has a structure that does not transmit the vibration of the ship. In this specification, the explanation has been limited to the driving of steel pipe piles, but the pile material is not limited to steel, and concrete can also be used.

[Brief explanation of drawings]

Figure 1: Example of the steel pipe pile driving method using ship scaffolding, Figure 2: Schematic diagram of the excavator, Figure 3: Detailed view of the pushing device, Figure 4: Overall view of the pile driving part, Figure 5
Figure: Example of applying the pushing device to a diagonal pile 1...Ship scaffolding, 2...Steel pipe pile, 3...Piece pushing device, 4...Rotless rotary hole-expanding excavator, 5
... Crane, 6 ... Excavation bit, 7 ... Underwater motor, 8 ... Hanging wire, 9 ... Captire cable, 10 ... Excavation shear discharge hose, 11 ...
...Brake cable, 12...Drilling bit shaft, 13
... Central axis of the excavator, 14 ... Guide, 15 ...
Mast, 16...Boom, 17...Cylinder for steel pipe tilting, 18...Piece pushing part, 19...Opening/closing hydraulic chuck, 20...Opening/closing guide, 21...
... Cylinder for pushing steel pipes, 22 ... Cylinder for holding mast, 23 ... Accumulator, 24 ...
Auxiliary cylinder, A: Sedimentary layer, B: Rock layer.

Claims (1)

[Scope of Claims] 1. A rotary hole-expanding excavator placed underwater at the lower end of the inside of a steel pipe pile, a hoisting machine of the excavator placed on a floating work scaffold above the steel pipe pile, and a tilting machine placed on the outer periphery of the steel pipe pile. A pile pushing device consisting of a pushing cylinder is used to drive the steel pipe pile vertically or inclined by the excavator and push the steel pipe pile into the ground without transmitting the vibration of the floating work scaffold to the steel pipe pile. The process of repeating the above steps alternately, and the pushing of the steel pipe pile to a predetermined depth is completed,
After the excavator is hoisted up and removed by the hoisting machine, a step of driving a steel pipe pile using a percussion type pile driver, and a step of injecting mortar into the inside and outside of the steel pipe pile from the tip to integrate the steel pipe pile and the ground. A method of driving steel pipe piles. 2. A mast equipped with a cylinder mechanism installed on a floating work scaffold, a mast holding cylinder installed at an angle on the mast, and an absorber installed on the above two types of cylinders to absorb the swinging of the floating work scaffold. a steel pipe pushing cylinder attached to the boom of the mast; an opening/closing hydraulic chuck for grasping the steel pipe pushing cylinder attached to the pushing cylinder; and a steel pipe erected on a concentric axis of the opening/closing hydraulic chuck. and a steel pipe pile driving device, which comprises an opening/closing type guide for replenishing, and a steel pipe pile tilting cylinder arranged between the steel pipe pile pushing cylinder and the mast.