JPH0118205B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground improvement method for improving relatively shallow and soft ground such as bedrock at the bottom of a dry ivy pond or clay embankment.

Conventionally, various construction methods such as the cement mixing method, sand drain method, etc. have been adopted as methods for improving soft ground. It is difficult to mix, and when using the sand drain method, it takes a long time for the water to be completely drained and the ground to be strengthened. Other soft ground that requires improvement include the sludge layer at the bottom of a dry ivy pond and a clay embankment layer, and the thickness of this layer is often within 1 to 2 meters. There was no suitable construction method that could efficiently and uniformly improve such relatively shallow soft ground within a short period of time.

The purpose of this invention is to provide a ground improvement method that can uniformly improve relatively shallow soft ground within a short time and day with high efficiency.

The method of the present invention is to support a device in which a discharge pipe is provided near the vibrating body of a vibrating ground compaction machine with a crane, and discharge the soil consolidation agent and air into the soil from the discharge pipe while the vibrating body is discharged from the vibrating body. The method is characterized by comprising a step of sinking the device into the soil by vibration, and a step of gradually lifting the device while vibrating the vibrating body after stopping discharge from its discharge pipe.

The vibratory ground compaction machine used in this invention has one or more vibrating bodies that house a vibration prime mover and an eccentric weight rotatably driven by the prime mover in a vertically elongated envelope, and is chained by a crane. Alternatively, a configuration in which the device is supported via a wire rope is optimal in terms of ease of position change operation. Both the consolidation agent and air, and only air, can be pumped through the hose to the discharge pipe provided in the vibrating ground compaction machine. A suitable consolidation agent to be used is, for example, Sumitomo Cement Co., Ltd.'s cement-based soil improver "Taflock", which can effectively consolidate even organic soils. The amount to be used is determined by a consolidation test on soil samples taken in advance.

In this invention, in the step of submerging the vibrating body into the soil while discharging the compacting agent and air, the compacting agent is added into the soil together with the air and vibration is applied at the same time, so the presence of the air causes the soil to loosen. It is stirred to create fluidity and a caking agent is mixed in.
Then, in the process of stopping the discharge and gradually raising the vibrating body, air is ejected to the ground side and the ground is compacted. Each of the above steps is repeated at different positions over the entire area of the ground to be improved, and the ground improvement work is completed.

The soil that has been constructed in this manner will develop high strength within a few days due to the solidification effect of the soil consolidation agent, and no compaction is required after construction.

Therefore, according to the present invention, it is possible to mix a consolidation agent, stir, and compact the ground that is soft enough that it is not necessary to use an auger, such as sludge at the bottom of a dried-up pond or clay embankment. can be done all at once,
Ground improvement can be carried out uniformly and efficiently within a short period of time.

Examples of the present invention will be described below. Figure 1 shows an example of equipment used in the construction method of the present invention, in which 1 is a vibrating ground compaction machine, 2 is a discharge pipe, 3 is a wire rope, 4 is a crane truck, and 5 is a compaction agent supply and compression machine. This is an air and power supply device. As shown in Fig. 2, the soil compaction machine 1 has three vibrating bodies 10 each having an electric motor and an eccentric weight attached to its rotating shaft housed in a vertically elongated envelope, mounted on a heavy frame 11. The envelope vibrates as the motor rotates. 12 in the figure is an electric wire. Two discharge pipes 2 are supported on the frame 11. A check valve 2a is provided at the lower end of the discharge pipe 2, and a hose 13 connected to the supply device 5 is connected to the upper end so that both solidifying agent and air can be discharged from the discharge pipe 2. It's summery. A suitable position of the frame 11 is supported by a boom 15 via a wire rope 14, and the compaction machine 1 provided with a discharge pipe 2 can be raised and lowered at a desired position on the crane vehicle 4 side. In the figure, 15 is a wire rope joint.

During construction, the vibrating body 10 is constantly vibrated, and the compaction machine with a discharge pipe is first lowered into the ground to be constructed while discharging solidifying agent and air from the discharge pipe 2, and the soil is loosened by its own weight and vibration. Submerge it to the specified depth. Next, while the air is still in the lowered state, stop discharging the air and gradually pull it out, the air is forced out to the ground surface, the soil is compacted, and the compactor with the discharge pipe is pulled out to the ground surface. The construction of that part is completed.
By changing the position of this lowering and raising operation little by little,
Perform this on the entire ground area to be improved.

In the above embodiment, the compaction machine with a discharge pipe is lowered once and then raised to finish the construction of that part. In some cases, the mixture may not be sufficiently mixed. In such a case, it is advisable to insert a process in which only air is discharged from the discharge pipe 2 after one descent, and a step of raising and lowering the discharge pipe 2 from 1 to 3 times as necessary.

Furthermore, in the apparatus in which the vibrating ground compaction machine used in the above embodiment is provided with a discharge pipe, the vibrating body 10 is
Although there are two discharge pipes 2 in this case, there is no problem in increasing or decreasing the number as appropriate.For example, devices 41, 42, 43, and 44 having the configurations shown in FIGS. 4 to 7 may be used. be able to. In the same figure, 41a, 42
a, 43a, and 44a each indicate a frame, and the third
Parts equivalent to those in the figure are indicated by the same reference numerals.

[Brief explanation of drawings]

Fig. 1 is a schematic side view of a device used in an embodiment of the present invention, Fig. 2 is a partially enlarged view of Fig. 1, Fig. 3 is a plan view corresponding to Fig. 2, and Figs. 4 and 5. , 6 and 7 are schematic plan views of a vibratory soil compaction machine equipped with a discharge pipe, respectively, which can be used in the method of the present invention. 1... Vibratory ground compaction machine, 2... Discharge pipe, 3
...wire rope, 4...crane truck, 10...
Vibrating body, 11... Frame, 12... Electric wire, 13
...Hose, 14...Wire rope.

Claims (1)

[Claims] 1. A device with a discharge pipe installed near the vibrating body of a vibrating ground compaction machine is supported by a crane, and soil compacting agent and air are discharged into the soil from the discharge pipe, and the vibration of the vibrating body causes the soil to flow into the soil. A soft ground improvement method comprising a step of sinking the device, and a step of gradually lifting the device while vibrating the vibrating body by stopping discharge from its discharge pipe.