JPS60144420A - Jet piling work - Google Patents

Abstract

PURPOSE:To exactly and easily remove slime by a method in which when a steel tubular pile is driven while excavating the ground by high-pressure jet water, broken rocks formed in driving the pile are discharged with water through a suction hose inserted into the pile. CONSTITUTION:A jet pump 5 and a sand pump 7 are actuated to operate a vibro-hammer 3, and high-pressure jet water is jetted from a nozzle at the tip of a water jet pipe 2 toward the tip portion of a steel tubular pile 1 to excavate the ground E. The pile 1 is then driven. Rocks broken by the actions of high- pressure jet water and the striking of the pile 1 are sucked and discharged with water through a suction hose 6. During the period, the pile 1 can be driven to a given depth.

Description

[Detailed description of the invention] (Industrial application field) The present invention uses high-pressure jet water and a vibrating pile driver in combination,
This relates to the jet pile construction method, in which steel pipe piles are driven into hard ground beneath the water surface.

(Prior Art) Recently, a jet pile method using a combination of high-pressure jet water and a vibrating pile driver has been known as a construction method for driving steel pipe piles into hard ground such as bedrock.

In the conventional jet pile construction method, high-pressure jet water is injected from a predetermined number of water jet piles attached to a steel pipe pile at the tip of the steel pipe pile to excavate and crush hard ground, while the steel pipe pile is driven into the hard ground by a vibrating pile driver. I was typing.

By the way, when driving steel pipe piles into bedrock etc. using the jet pile method, the jet water is used to drive the piles with an arsenal effect, so there is a slight gap between the steel pipe piles and the bedrock, so it is difficult to expect much resistance to pull them out from the bedrock. I couldn't.

Therefore, if pull-out resistance is expected, cement milk or mortar must be injected into the gap between the steel pipe pile and the bedrock to firmly fix the steel pipe pile to the cement milk layer or mortar layer.

However, near the tip of the steel pipe pile, there is a slime made of crushed rock and water that was crushed by the impact force of the pile itself and the jet pressure of jet water, and this creates the desired cement milk layer or mortar layer. There was a problem that it could not be formed. Currently, slime is removed by using jet water for driving piles, but with this method, the jet water rises through the two gaps between the steel pipe pile and the rock, inside and outside the steel pipe pile, so the rising water flow itself It is said that the flow velocity becomes low, making it difficult to ensure slime removal, and that if a large amount of high-pressure jet water is injected to increase the flow velocity, the force of the vibrating pile driver will be reduced by the action of the reverse jet force. There was a problem.

(Object of the Invention) The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a jet pile construction method that can reliably and easily remove slime made of p1 crushed rock and water.

(Structure of the Invention) In order to achieve the above object, the method of the present invention injects high-pressure jet water at the tip of the steel pipe pile from a predetermined number of water jet pipes attached to the steel pipe pile to excavate the hard ground beneath the water surface and excavate sandstone. In the jet pile construction method, in which steel pipe piles are driven into MiJ hard ground using a vibrating pile driver, crushed rock generated by driving the steel pipe piles along with water is passed through a suction hose inserted into the steel pipe pile when driving the steel pipe piles. It is characterized by discharging.

(Example) An embodiment of the construction method of the present invention will be described below with reference to the drawings.

In carrying out the construction method of the present invention, first, as shown in FIG. 1, a water jet pipe 2, a vibrohammer 3 as a vibrating pile driver, and a suction hose 6 are attached to a steel pipe pile 1, as shown in FIG.

The water jet pipe 2 is placed along the outer wall surface of the steel pipe pile 1.
The tip thereof is positioned near the tip of the steel pipe pile 1 and attached so that it can be pulled out and removed. Preferably, several water jet pipes 2 are installed at intervals in the circumferential direction of the steel pipe pile 1 as shown in the illustrated example. Each water jet pipe 2 is connected to a high pressure hose 4 via a flexible high pressure hose 4 so that a jet of water can be ejected from a nozzle at the tip at a pressure and water volume sufficient to drill sandstone through hard ground and reduce back jet action. It is connected to a water pressure jet pump 5. Note that the water jet pipe 2 may be installed along the inner wall of the steel pipe pile 1.

The vibrohammer 3 is detachably attached to the upper end of the steel pipe pile 1 and transmits vibrations generated by the vibrohammer 3 itself to the steel pipe pile 1 that is driven into hard ground.

This vibrohammer 3 is suspended from a crane on a ship, which is not shown.

The suction hose 6 is a flexible hose, and as shown in FIG. 2, when driving the steel pipe pile 1, it is inserted from the upper end opening of the steel pipe pile 1 so that its tip reaches near the surface of the hard ground E below the water surface. The base end thereof is connected to a suction sand pump 7 located on a ship (not shown).

In FIG. 1, numeral 8 is a power supply cable for pipe Rohan-3.

As shown in Figure 1, in order to drive the steel pipe pile 1 with each member attached into the hard ground below the water surface, first position it, and in this state start the jet pump 5 and sand pump 7 to start the vibronomer 3. and start driving the steel pipe pile 1.

During driving, as shown in FIG. 2, high-pressure jet water is injected from the nozzles at the ends of a plurality of water jet pipes 2 at the ends of the steel pipe piles 1 to excavate the hard ground E below the water surface. At the same time, the vibrations caused by the vibro-numer 3 are transmitted to the steel pipe pile 1, and the tip of the steel pipe pile 1 enters the hard ground E by striking sandstone. Moreover, the rock crushed by the impact of the steel pipe pile 1 and the action of high-pressure jet water is sucked and discharged together with water by the suction hose B in the steel pipe pile 1 whose tip is located near the surface of the hard ground E. .

To explain the mechanism for discharging crushed rock in detail, when the water inside the steel pipe 1 is sucked by the suction hose B, the water level inside the steel pipe pile 1 decreases, creating a water level difference between the outside and inside of the steel pipe pile 1. Due to the water level difference, the water (seawater) outside the steel pipe pile 1 is combined with jet water and forms a rapid flow in one direction from the outside to the inside of the steel pipe pile 1 as shown by the arrow in Figure 2. At this time, the crushed rock is caught in the rushing water in one direction and is carried to the surface of the hard ground 8 inside the steel pipe pile 1, where it is easily discharged through the suction hose 6.

Driving is performed while sucking and discharging the crushed rock in this way, and the steel pipe pile 1 is driven to a predetermined depth.

When driving is completed, the jet water jet from the water jet pipe 2 is stopped, and the vibrating action of the bipronometer 6 is also stopped. Thereafter, as shown in FIG. 5, the steel pipe pile 1 is pulled out a little, cement milk or mortar is injected into the hole in the hard ground E created by driving the steel pipe pile 10, and a cement milk layer or mortar layer 9 is placed in this hole. form,
Next, as shown in FIG. 4, the steel pipe pile 1 is coated with a cement milk layer or a mortar layer by the action of a vibrohammer 3. The inside was re-concrete and a complete grafting process was performed.

After the above steps, the bipronominal 5 is removed, and the water jet pipe 2 is pulled out and removed.

Thereby, the steel pipe pile 1 can be erected in the hard ground E below the water surface.

In the method of the present invention, a sand pump 7 of a size that can be inserted into the steel pipe pile 1 is attached to the tip of the suction hose 6 to remove insects from crushed rock when driving into the steel pipe pile 1. The suction and discharge action by the suction hose 6 may be further increased.

(Effects of the Invention) As explained above, according to the construction method of the present invention, when a steel pipe pile is driven into hard ground below the water surface using high-pressure jet water and vibration, the crushed rock generated during driving is removed from the steel pipe pile. The suction action of the suction hose inserted into the pile allows it to be easily removed by entraining it in the unidirectional rapid water flowing from the outer wall to the inner wall of the steel pipe pile. Therefore, in the construction method of the present invention, a mortar layer spanning the cement milk layer can be easily and reliably formed in the gap between the steel pipe pile and the bedrock after driving, and the tip of the steel pipe pile is embedded in the cement milk layer or the mortar layer. It can be firmly erected in hard ground beneath the water surface with high pull-out resistance.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the steel pipe pile used in the method of the present invention, Figure 2 is an elevation view showing the steel pipe pile in Figure 1 being driven into hard ground below water, and Figure 3 is after driving is completed. FIG. 4 is an elevational view showing a state in which a cement milk layer is formed on the tip side of a steel pipe pile, and FIG. 4 is an elevational view showing a state in which the steel pipe pile is erected in hard ground below the water surface. 1... Steel pipe pile 2... Water jet pipe 3... Vibro hammer (vibrating pile driver) 6... Suction hose 9... Cement milk layer or mortar layer E... Hard ground patent under water surface Applicant: Toyo Kensetsu Co., Ltd. Agent: Patent attorney: Yumi Kaede (Ooka or one person)

Claims (1)

[Claims] (1) High-pressure jet water is injected from a predetermined number of water jet pipes attached to the steel pipe pile at the tip of the steel pipe pile to excavate and crush the hard ground below the water surface, and the steel pipe pile is driven into the hard ground by a vibrating pile driver. A jet pile construction method in which crushed rock produced by driving a steel pipe pile is discharged together with water through a suction hose inserted into the steel pipe pile.