JP2886356B2 - Vibration compaction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for compacting a ground which is liable to be liquefied by vibrations, such as a saturated loose sand ground or a sandy ground having a high fine particle content. It is related to the method of construction.

[0002]

2. Description of the Related Art Conventionally, vibration compaction methods such as rod compaction method, vibro flotation method, direct power compaction method, vibro flotting method, etc. have been used to compact the ground by vibrating a vibrating rod while vibrating a saturated sand ground. The method of hardening is known.

[0003] However, in any of the above-mentioned construction methods, since the loose sand ground is directly vibrated, excessive pore water pressure is generated by the same mechanism as at the time of the earthquake, and it is inevitable that the rod periphery becomes muddy (liquefied). .

[0004] As a result, there is a problem that the vibration energy is rapidly attenuated in the vicinity of the vibration rod, and the compaction effect is greatly reduced.

Further, when the target sand ground contains fine grains, the vibration energy is more greatly attenuated, and there is a problem that the compaction effect by the vibration rod method is extremely low.

Conventionally, a large number of drain pipes are driven into the deep part of the soft ground, and then a plurality of sand compaction piles are driven into the shallow part of the surrounding ground by a vibro composer method, and the ground is integrated by the volume of the sand compaction pile. Along with the compression, the deep part of the ground is compressed by the land subsidence due to the impact or vibration at the time of pile driving, and the water contained in the soft ground flows out to the drain pipe along the pressure gradient and is discharged by the compression force. ,
There is also known a compaction method in which groundwater is reduced by the water compaction effect.

However, in this method, since the ground is compressed by discharging water by compressing the ground to lower the groundwater and compacting by the water-tightening effect, almost no excessive pore water pressure is generated, and sufficient tightening is not performed. No hardening effect is obtained.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a vibration compaction method using a vibrating rod, in which a vibrating rod is liquefied due to the generation of excessive pore water pressure, and vibration energy is rapidly attenuated near the vibrating rod. An object of the present invention is to solve the problem that the compacting effect is significantly reduced.

[0009]

According to the present invention, in order to solve the above-mentioned conventional problems, a plurality of suction pipes 2 are arranged close to a vibrating rod 1 and the vibrating rod 1 is connected to a vibrator. 4, press-fitting is performed integrally with the water-suction and squirt pipe 2 while causing vertical vibration or shear vibration, and while jetting a water jet from the water-sucking portion 2 'of the water-suction and squirt pipe 2, the ground is compacted, and the vibration is applied to the ground. The present invention proposes a vibration compaction method in which the excess pore water pressure generated in the above is eliminated by the suction and fountain pipe 2.

According to the present invention, a plurality of drainage pipes are arranged close to each other around the vibrating rod 1, and the vibrating rod 1 is press-fitted integrally with the drainage pipe 3 while being vibrated vertically or sheared by the vibrator 4. Another object of the present invention is to provide a vibration compaction method in which the ground is compacted and, at the same time, excess pore water pressure generated in the ground by the vibration is eliminated by the drain pipe 3.

[0011]

The vibrating rod 1 is press-fitted into the ground together with the suction / fountain pipe 2 or the drain pipe 3 while being vibrated vertically or sheared by the vibrator 4.

At this time, when the water-suction and squirt pipe 2 is used, a water pump is connected to the water-suction and squirt pipe 2, and the resistance of press-fitting is reduced by the vibration of the vibrating rod 1 and the jet of a water jet from the water-sucking section 2 ′ of the suction-squirt pipe 2. The water suction and squirt pipe 2 can be easily press-fitted integrally with the water squirt and water squirt pipe 2, and the water suction part 2 'of the suction and squirt water pipe 2 is prevented from being clogged.

Excess pore water generated by vibration of the vibrating rod 1 during compaction by vibration is absorbed by the suction and squirt water pipe 2 or the drain pipe 3.
The liquid is forcibly or spontaneously discharged to the ground surface through the fins to prevent liquefaction around the vibrating rod 1, and the vibration energy of the vibrating rod 1 is effectively transmitted to the ground so that the vibration compaction is reliably performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of suction and discharge pipes 2 or drain pipes 3 are arranged near a vibrating rod 1 in the vicinity thereof, and a vibrator 4 is installed at the head thereof.

The suction and squirt pipe 2 is connected via a hose 5 to a water supply pump or a water absorption pump, and is switched to a water supply pump or a water absorption pump as needed to pump or discharge water.

FIGS. 1 and 2 show an example in which compaction is performed by a vibrating rod 1 in which a suction and squirt water pipe 2 is disposed. Press into the ground together with 2.

At this time, the suction and injection water pipe 2 is connected to a water pump, press-fitted while jetting a water jet from the water suction part 2 ', and vibrated integrally with the suction and injection water pipe 2 which becomes a resistance to the press-fitting due to the injection of the water jet. In addition to facilitating the press-fitting of the rod 1, the clogging of the water suction part 2 'of the water suction and fountain tube 2 is prevented.

The vibrating rod 1 is press-fitted while vibrating as described above, and the ground is compacted by the vibration. At the same time, the pump is switched to a drainage pump after the press-fitting, and the excess pore water pressure generated in the ground due to the vibration is absorbed by the suction pipe 2. By forcibly removing the vibration, the vibration energy is effectively transmitted to the ground, and the compaction is surely performed without damping the vibration energy.

FIGS. 3 and 4 show an example of the structure of the vibrating rod 1 integrated with the suction and fountain pipe 2. FIG. 3 shows a case in which the vibrator 4 vertically vibrates, and FIG. This shows a case where the vibrating device 4 shears and vibrates the split vibration rod 1.

Next, FIGS. 5 and 6 show an example in which a drainage pipe 3 for natural drainage made of a perforated pipe or the like is arranged on a vibrating rod 1, and FIG. 3 shows a case where the vibrator 4 vertically vibrates. Reference numeral 4 denotes a case in which the vibrator 4 causes shear vibration. The vibrating rod 1 is pressed into the ground while vibrating the vibrator 4 in the same manner as described above.

In this case, by naturally draining excess pore water pressure generated in the ground due to vibration during vibration compaction, the vibration energy is effectively transmitted to the ground as described above, and the vibration energy is attenuated. Compaction can be performed without any problem.

When the vibration rod 1 is press-fitted, it is possible to connect a water supply pump to the drain pipe 3 and press-fit it while jetting a water jet.

[0023]

As described above, according to the present invention, the vibration energy of the vibrating rod is effectively transmitted to the ground by removing the excess pore water pressure during compaction, and the N value after compaction and the strength (resistance) against liquefaction. ) Can be increased.

In addition, since the effective range of compaction is expanded, it is possible to reduce the construction period and construction cost by increasing the compaction work pitch, and if the work is performed at the same pitch as before, the N value will increase. In addition, improvement in earthquake resistance is expected, and it is possible to cope with prevention of liquefaction even in the case of a stronger earthquake.

Further, the effect of vibration compaction is exerted even on a sand ground containing fine particles, and the compaction of the ground, which is difficult with the conventional vibration compaction, becomes possible.

Since the suction pipe and the drain pipe are pressed into the ground integrally with the vibrating rod, the construction can be simplified and the efficiency can be simplified as compared with the case where the drain pipe is pressed separately from the vibrating rod. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a construction state according to the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a construction state according to the present invention.

FIG. 3 is a side view showing one embodiment of a vibrating rod used in the present invention.

FIG. 4 is a side view showing another embodiment of the vibration rod used in the present invention.

FIG. 5 is a side view showing another embodiment of the vibration rod used in the present invention.

FIG. 6 is a side view showing another embodiment of the vibration rod used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration rod 2 Suction and fountain pipe 2 'Water absorption part 3 Drain pipe 4 Vibrator 5 Hose

Claims (2)

(57) [Claims] 1. A plurality of water suction and fountain pipes are arranged close to a vibrating rod, and the vibration rod is integrated with the water and water squirt pipes while causing the vibration rod to vibrate vertically or shear. A vibration compaction method characterized by compacting the ground by injecting water jets while jetting a water jet from the part, and removing the excess pore water pressure generated in the ground by the vibration at the same time by the suction and injection water pipe. 2. A plurality of drain pipes are arranged close to each other around a vibrating rod, and the vibrating rod is press-fitted integrally with the drain pipe while vertically or shear vibrating to compact the ground, A vibration compaction method characterized in that excessive pore water pressure generated in the ground due to vibration is eliminated by the drain pipe.