JPS6073912A - Dehydration type rod compaction method - Google Patents

Abstract

PURPOSE:To perform efficient compaction of a sandy ground saturated with underground water, by a method wherein ground water around a vibration compacting rod is expelled to a dehydration space formed in the vibration compacting rod. CONSTITUTION:By communicating a dehydration space with the open air, ground water around a hollow tube 1 is caused to naturally flow in th dehydration space by a pressure during vibrating compaction. A shape steel, formed with an H-steel 14, a projection 15, a water permeable pipe 16, and a small pipe 17, is used as a vibration compacting rod. Further, the water permeable pipe 16 forms a dehydration space, and the small pipe 17 leads from the permeable pipe 16 to a position in the vicinity of the top end of the rod to form a pipe for exhaust gas or drainage. This enables a ground around the vibration compacting rod to be expelled the dehydration space, resulting in the possibility to prevent the generation of an excess gap water pressure.

Description

[Detailed description of the invention] The present invention is based on the Rondo method, which is a type of sandy ground vibration compaction method.
This relates to the compaction method.

The Iwayururondo compaction method is a method in which a vibration compaction rondo made of steel pipes, H-beams, etc. is penetrated into the ground, and compaction is performed by vibration while supplying sand, gravel, crushed stone, etc. from the ground surface to the sides of the rondo. This construction method has been widely used in recent years because it is a construction method that is easy to use.However, when this construction method is implemented on sandy ground saturated with groundwater, excessive pore water pressure may be generated. Since the ground water (pore water) between sand particles interferes with the relative movement of sand particles and their tendency to become denser due to the vibrational force applied through the rond, it is necessary to properly release this ground water. If you do that, it should be resolved.

The present invention is an attempt to solve the above-mentioned problems based on this point of view.The present invention is characterized by:
The purpose of this system is to release ground water around the vibratory compaction rond into the dewatering space attached to the vibratory compaction rond.

Hereinafter, the points that the method of the present invention is the same as the conventional method will be omitted, and dewatering will be specifically explained.

Figures 1 to 4 are explanatory diagrams of the case where a hollow tube is used as a vibration compaction rond and the inside thereof is used as a dewatering space. In the figures, 1 is a hollow tube, 2 is an exciter, 3 is a permeable part, 4 is a ground surface, and 5 is a groundwater level (still water level).

Both have a strainer structure, such as by appropriately covering the inner surface with a mesh wire gauze, and are provided at appropriate locations (mainly at the lower end) as part of the hollow tube 1.

Figure 1 shows a case where the dewatering space is communicated with the atmosphere so that ground water around the hollow tube 1 naturally enters the dewatering space under the pressure during vibration compaction). (a),
In (b), when the entire inside of the hollow tube 1 is made into a dehydration space,
(C) is a case where only the lower part of the hollow tube 1 is used as a dehydration space. Since the upper end opening of the hollow tube 1 is usually not sealed, it can be left as it is in (a), but in (b), the upper end opening of the tube 6 is not sealed.
The inside of the hollow tube 1 is communicated with the atmosphere through the. In (C), the pipe 7 is for communicating with the atmosphere.

Figure 2 shows a case where the deaeration space is sealed and the air inside is removed by pump 8 to facilitate the ingress of ground water; (a) in the figure shows a hollow space. When the entire inside of the tube 1 is used as a dehydration space, (b) is a case where only the lower part of the hollow tube 1 is used as a dehydration space! 0, in the case of (b), the space for degassing is smaller than in the case of (a).

In the case of Figures 1 and 2, at an appropriate stage of construction, for example, at the end of one construction job after compaction from a predetermined depth to the ground surface,
The water accumulated in the hollow tube 1 is drained by appropriate means.
If only a small amount of water accumulates during one construction, it is possible to omit draining the water during at least one construction.

FIG. 3 shows a case in which the water accumulated in the hollow tube 1 is discharged by a pump means, as shown in FIG. 3(a).

(b) is the case where the water pump 9 is installed on the ground, (
In case b), the flexible hose 11 is connected to the drain pipe 10, which has a shorter rising length than in case (a), and is connected to the drum 12.
It is wrapped around. Case (C) differs from Φ) in that the pump 13 is installed in the dewatering space; in this case, an appropriate buffer material may be interposed between the pump 13 and the hollow pipe 1. preferable.

Figure 4 shows a case where the groundwater level around the hollow pipe 1 is lowered by actively discharging the water in the dewatering space. It is necessary to choose between gravity drainage and forced drainage using negative pressure (for example, Well Point).

5 and 6 are explanatory diagrams of the case where a shaped steel is used as a vibration compaction iron. In the figures, 14 is an H-shaped steel, 15 is a protrusion, 16 is a permeable pipe, and 17 is a small diameter pipe.

The water permeable pipe 16 has a strainer structure similar to that of the water permeable part 3, and its interior corresponds to the dewatering space in the present invention.

The small diameter pipe 17 extends from the water permeable pipe 16 to near the upper end of the rond, and corresponds to the exhaust pipe 7 or the drain pipe 10.

FIG. 5 shows that when water permeation pipes 16 are installed on both sides of the web at the lower end of a single H-shaped steel that constitutes the rondo, the sixth
The figure shows a case where a common water permeable pipe 16 is attached to the lower end of a rond made up of a plurality of H-shaped steels 14.

The manner of dewatering using these water permeable pipes 16 is the same as that in the case where only the lower part of the hollow pipe 1 is used as the dewatering space, so a description thereof will be omitted.

In the construction method of the present invention, as described above, the ground around the vibration compaction rond is released into the dewatering space, thereby preventing excessive pore water pressure from occurring. Hardening can be performed efficiently.

[Brief explanation of drawings]

Figures 1 to 4 are explanatory diagrams when a hollow tube is used as the vibratory compaction rond, and Figures 5 and 6 are explanatory diagrams when a shaped steel (H type vI4) is used as the vibratory compaction rond. It is. In the figure, 1...Hollow tube, 2...Exciter, 3...Permeable part, 1-Sugae-I-〇 Patent applicant Fudo Construction Co., Ltd. Representative patent attorney Hiroshi Sometani No. 1 Figure (a) (b) (c) Tomi L Figure 3 (a) (b) (c) Figure 4 Figure 5 (CI) (b) Figure 6 (G) (b)

Claims (1)

[Claims] A dewatering rod compaction method characterized by releasing ground water around the vibratory compaction rond into a dewatering space attached to the vibratory compaction rond during the process of compacting sandy ground by the penetration of the vibratory compaction rond. .