JPH0339515A - Soil improvement method employing sand pile construction barge - Google Patents

Abstract

PURPOSE:To improve efficiency in executing work by a method wherein a tamper is installed to the outer periphery at the lower end of a hollow pipe of a sand pile construction barge, gravels or the like are dispersed through the hollow pipe to the seabed subsoil and the gravels or the like are leveled and compacted by vibration produced by a vibro pile hammer installed to the head of the hollow pipe. CONSTITUTION:As sands are supplied to the inside of a hollow pipe 4 for sand pile construction that is erected on the side of a sand pile construction barge, compaction is applied thereto with a vibro pile hammer 2 and a sand pile is constructed thereby in the seabed subsoil 16. After drawing up the hollow pipe 4 and installing a tamper 5 thereto at its lower end, materials for mound construction such as sands, gravels, crushed stones or the like are discharged through the hollow pipe 4 to the place where the subsoil is strengthened with the sand pile. Then, by operation of the vibro pile hammer 2, vibration is applied to the tamper 5 for compacting the mound construction materials, and the mound is constructed thereby.

Description

[Detailed Description of the Invention] (a) Technical field The present invention relates to a method for improving seabed soil, and more specifically, it involves not only sand piles, but also sand pile construction vessels that are used to create mounds and compact and level them. It provides a highly efficient method for performing tasks.

(b) Prior Art In 2007, from the standpoint of advanced utilization of marine rooms, port structures tend to be deployed offshore, with greater depth and larger scale, and their construction conditions are becoming increasingly severe. The conventional work carried out by divers has many problems in terms of efficiency, safety, economy, etc., and there is a desire for the development of various underwater working machines and effective construction methods.

Generally, when building port structures on soft ground, sand piles are built in advance on the seabed to strengthen the soft ground, and mounds are created to distribute the load.

In this case, the mound was compacted by hanging concrete blocks, weights, etc. on a crane ship and letting them fall naturally.
1@Energy is significantly reduced due to water resistance, buoyancy, and water cushion when landing on the bottom, and furthermore, positional deviation occurs, making it impossible to obtain sufficient effects.

In addition, a compaction method for soft ground has been proposed, as disclosed in Japanese Patent Application Laid-Open No. 58-26109, but this method involves exposing one end of the rondo above the sea surface and hitting it with a hammer installed on a crane ship or the like. This is a method of compacting soft ground on the ocean floor by applying vibrations, and it is extremely inefficient as the compaction material must be transported and put in separately.

(C) Disclosure of the Invention In view of the above-mentioned conventional problems, the present invention provides a method for constructing sand piles by using a sand pile construction vessel and introducing necessary materials through a hollow pipe for sand pile construction. This paper proposes a ground improvement method that allows the construction of mounds, their compaction, and leveling work to be carried out continuously using the same machine, and that allows for highly efficient and highly accurate construction.

The first feature of the construction method of the present invention is that it uses a work boat, which has conventionally been used extensively for sand pile construction, to compact and level the seabed soil at the lower end of the hollow pipe for sand pile construction. A tamper (tamping plate) is removably attached, and a compacting and leveling material 4 is introduced into the hollow tube from a hopper provided at the E section of the hollow tube, and discharged and distributed from the lower end of the hollow tube to the seabed. The purpose of this method is to tighten and level the leveling material using the vibration of a vibrohammer attached to the hollow tube head.

The second feature is that this sand pile construction ship deposits regular sand piles into the soft ground on the seabed, and then creates a strong mound on top of the cane ground. A tamper for compacting and leveling the mound is attached to the lower end of the hollow tube, and mound-creating, compacting and leveling material is introduced into the hollow tube from the hopper attached to the 4th part of the hollow tube. The contents are discharged onto the ground from the lower end of the tube to create a mound, and the mound is compacted and leveled by vibrations of a vibrohammer attached to the head of the hollow tube.

Next, one embodiment of the method of the present invention will be explained using drawings.

(D) Embodiment Figure 1 shows an example of the entire apparatus for carrying out the method of the present invention, in which a sand pile construction ship 1 has a sand pile construction hollow pipe 4 with a hopper 3 installed on the top. The hollow tube 4 is suspended along the upright leader 6, and the hollow tube 4 is suspended above the ship.
Along with the winch 7 and wire rope 8 for raising and lowering the sand and 79. Belt conveyor 10. It is equipped with conveyance devices such as a ground hopper 11 and a packet 12.

A vibrohammer 2 is attached to the head of the hollow tube 4 described in E. The hollow tube 4 is suspended from a wire rope 8 via a pulley 13, and is configured to be raised and lowered by the drive of a winch 7. ing.

Then, a tamper 5 (protruding plate) is provided on the outer periphery of the lower end of the hollow tube 4.
is removably attached.

Next, as an example of the method of the present invention, the steps of creating a sand pile, building a mound, and compacting and leveling the sand pile will be explained with reference to FIG.

First, using this sand pile building vessel 1, sand piles (sand compaction piles) are built into a predetermined soft seabed ground 16 by a normal method using a vibro hammer 2 or the like on the head while supplying sand into the hollow v4. 17 (Figure 3 (a))
.

Next, a mound 18 is constructed at a place where the ground has been strengthened by the sand piles 17 using the sand pile construction ship l. Medium in this case? Once the tube 4 is pulled out, the tamper 5 described above is attached to the lower end thereof by bolting or the like.

Materials for mound construction such as sand, gravel, crushed stone etc. should be placed on sand piles 17 first.
Once stocked in the sand bin 9 used during construction, it is transported to the ground hopper 11 by a belt conveyor 10, raised and lowered by a winch 15, transferred to a hecket 12 at a predetermined time, and thrown into the hopper 3 above the hollow tube 4. Ru. The material in the hollow W4 is discharged and scattered from the lower end of the hollow tube 4 to form the original shape of the mound 18 (FIG. 3 (b)).

At this time, use the vibrohammer 2 listed in L to shake it.
The creation of the mound 18 and its compaction may be performed simultaneously with the tamper 5 using the ribs.

Finally, the mound 18 is compacted and leveled using the Pablo hammer 2 (Fig. 3 (B) to (C)). At this time, the tamper 5 is attached to the lower end of the hollow tube 4 for the first time. You can.

During this compaction work, the mound 18 can be compacted more firmly by repeating the hoisting and unwinding operations of the hollow tube 4 to increase the compacting force by the tamper 5. In addition, when leveling the mound 18, the hollow tube 4 is pulled up to a predetermined level in order to adjust the height of the mound 18. We will compensate by replenishing building materials and vibrating the vibrohammer 2.

In addition, in this example, an example was explained in which a mound is constructed at a place where sand piles are to be constructed, assuming that the ground ai is good. However, although it is not necessary to construct sand piles, sand, etc.
Of course, the method of the present invention using the sand pile construction vessel can also be applied to places where it is necessary to perform compaction and leveling work using gravel or the like.

Also, 1 to compact the built mound slope;
It is also possible to attach the tamper 5 to the lower end of the hollow tube 4 so as to be inclined to match the angle of the slope, or to use a tamper whose angle matches the slope.

(E) Effects of the Invention The present invention can be achieved as described above by simply attaching a tamper to the lower end of the hollow pipe for sand pile construction installed on a sand pile construction ship, and then using the material supply device of the ship or the vibrohammer. etc., can be used as is, and the ship's construction management equipment is a depth gauge that measures the vertical movement of the hollow tube, a sand level meter that measures the height of the material inside the hollow tube, and a 2t111 ship positioning system. etc. can be used to perform highly accurate quality control of improved ground.

Moreover, with the method of the present invention, not only sand pile construction but also mound construction, compaction and leveling work can be carried out efficiently using the same sand pile construction ship, so the turning costs of the work ship and the hardware costs are reduced. It has many advantages such as being extremely economical as it becomes unnecessary.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of the entire apparatus for carrying out the method of the present invention. Figure 2 is an explanatory diagram showing the procedure for compaction and leveling in the method of the present invention. Figures 1w43 (a) to (c) are It is an explanatory diagram of the case where sand piles and mounds are created by the invention method. Code explanation 1-Sand a acid lead 2-Vibrohammer 3-Hopper
4-Hollow pipe for sand pile construction 5-Tamper 6-Leader 7-Winch 8-Wire rope 9-Sand bin lO-Belt conveyor 11
-Ground hopper 12-Packet t3-Pulley 14
-Wire rope 15-Winch 16-Seafloor ground 1
7-Sand pile 18-Mound

Claims (2)

[Claims] (1) A tamper is removably attached to the outer periphery of the lower end of a hollow pipe for sand pile construction on a sand pile construction ship, and compacted and leveled materials such as sand, gravel, crushed stone, etc. are supplied into the hollow pipe from the hopper at the top of the hollow pipe. A ground improvement method using a sand pile construction vessel, which is characterized by discharging and dispersing the material from the lower end of a hollow pipe onto the seabed ground, and compacting and leveling the material by vibration of a vibrohammer installed at the head of the hollow pipe. (2) After sand piles are constructed on the soft ground of the seabed by a sand pile construction ship, when creating a mound at the location where the sand piles will be constructed, a tamper is removably attached to the outer periphery of the lower end of the hollow pipe for sand pile construction. A mound is built by supplying mound creation and compaction leveling material into the hollow tube from a hopper at the top of the hollow tube and discharging it from the lower end of the hollow tube, and a vibrohammer that equips the head of the hollow tube with the mound. A ground improvement method using a sand pile construction vessel that is characterized by compaction and leveling.