JPS648134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for automatically creating sand bag pillars in an underwater pack drain construction method for creating sand bag pillars in soft ground such as the seabed.

Conventionally, the sand drain method using sand pillars has been widely adopted as a construction method for improving soft ground such as the seabed.

However, as the length of the sand pillar increases, problems arise during construction, such as sand cutting in the sand pillar, making it discontinuous or becoming thinner. Not only did it have a large diameter and required a large amount of sand, but the drain effect was unstable and its reliability was questionable.

Therefore, when a casing is driven into soft ground such as the seabed and a sand bag is dropped into the casing, the water below the sand bag inside the casing is discharged through a drain pipe by a pump.
The sandbag is deposited in soft ground such as the seabed, and the sandbag is deposited into the casing while adjusting the drainage amount to form a sandbag column, and then the casing etc. are removed leaving only the sandbag column. The invention of Japanese Patent Publication No. 16604/1983 regarding the construction method and equipment for forming pillars has been made, and it has been put to practical use as one of the effective construction methods for underwater pack drain construction.

However, in the above-mentioned conventional underwater pack drain construction method, the drain surface of each sand bag pillar, that is, the position of the sand surface inside the sand bag, is visually observed while supplying sand and water into the sand bag. In addition to adjusting the amount of water, the amount of water that has been filled in the casing beforehand is also controlled by the worker, and the problem is that high-speed sand bag pillar construction requires the skill of the worker and the need for a large number of workers. It was hot.

Therefore, the present invention solves the above-mentioned conventional problems,
The purpose is to improve the economic efficiency by speeding up the construction of sandbag pillars, save the labor required for the construction of sandbag pillars, that is, drains, and create more uniform drains. It is.

That is, in the automatic sand bag pillar construction method of the present invention, a casing is driven into soft ground such as the seabed, and water filled in the casing is discharged through a drain pipe, while the sand and water in the casing are poured into the sand. An underwater pack drain construction method in which a sand bag pillar is created by lowering the bag into the casing, and the casing etc. are removed leaving only the sand bag pillar in place in soft ground such as the seabed. Detects the position of the sand surface in the sand bag, and determines the amount of sand and water to be introduced into the sand bag and the drainage pipe from inside the casing so that the sand surface is always within a predetermined range. A feature of this method is that sandbag pillars can be created at any speed by controlling the amount of water discharged.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is an overall layout diagram of a sand bag pillar creation device to which the sand bag pillar automatic creation method in the underwater pack drain construction method of the present invention is applied; This figure is an enlarged side sectional view of the vicinity of the sand surface detection device shown in FIG. 1, and FIG. 3 is a plan view of the detector shown in FIG. 2.

First, in the sand bag pillar forming device shown in Fig.
Water W is present in the casing 2 in the state where it is driven. A sand bag 3 with a bottom is lowered into the casing 2 from a sand bag cassette 4, and is controlled by a supply sand amount adjusting device 8 via a primary sand hopper 5, a belt conveyor 6, and a secondary hopper 7. A fixed amount of sand S is supplied to the chute 10 by the feeder 9, and in this chute 10, a fixed amount of water supplied as indicated by the arrow W by the supply water amount adjusting device 11 is mixed into the sand S. The wet sand S is introduced into the sand bag 3 through the sand bag 12.

As described above, the sand bag 3 into which wet sand S containing water W is introduced from the tertiary hopper 12 descends inside the casing 2 as an underwater pack P, but the water W filled in the casing 2 in advance , is gradually discharged from the discharge port 14A to the outside of the casing 2 via a drain pipe 14 having a discharge water amount adjustment device 13,
In response, the underwater pack P becomes a sandbag column and descends inside the casing 2.

In addition, a sand surface detection device 16 is provided near the sand surface creation section 15 in the upper part of the casing 2, and the water W separated from the sand S in this section is collected in a separated water receiver 17 and then discharged from the discharge port 17A. are doing.

Next, this sand surface detection device 16 has a plurality of detectors 1, for example, three detectors 1, as shown in FIGS. 2 and 3.
6A, 16B, and 16c. For example, if the diameter of this sandbag pillar is D, a cylindrical member with a slightly smaller diameter d is divided into two, and one end of both members is rotatably connected with a hinge 18. However, by connecting the other end with a spring 19, the two members are kept lightly pressed against each other.

Therefore, when sand S is thrown into the sand bags 3 near these detectors 16A, 16B, and 16c, and the sand surface rises upward, the pressure of the sand S causes the two detectors forming the detectors to The parts are opened outward.

The opening is detected by the sand surface detection device 16.

Here, if the sand bag pillar is not opened beyond the diameter D, it will be detected that the sand S has been filled to this point.

On the other hand, when the sand level falls, the internal pressure disappears and the detectors 16A, 16B, 16C return to the diameter d.

When the diameter returns to d, the return is detected again.

The position of the sand surface is detected by the sand surface detection device 16 as described above, and a signal thereof is sent to the control device 20.

Therefore, by detecting the position of the sand surface by the sand surface detection device 16 and sending the signal to the control device 20, the respective supply amounts of sand S and water W flowing into the sand bag 3 are adjusted to the same amount of supplied sand. At the same time, the amount of water W discharged from the casing 2 through the drain pipe 14 is controlled via the discharge water amount adjusting device 13.

The control device 20, which has the function of automatically performing each of the above-mentioned controls, can control the construction speed of the underwater pack P, that is, the sand bag pillar, created within the casing 2 to an arbitrary speed.

That is, by detecting the sand surface position and adjusting the amount of sand and water supplied and the amount of water discharged through the drain pipe 14 so that the sand surface is always located within a predetermined range, the sand bag Pillars can be built at any speed. Therefore, it is possible to increase the speed of construction, and even in that case, it is possible to create a homogeneous sand bag pillar without sand chips at high speed.

Here, it is also effective to provide a pressure detection device 21 in the drain pipe 14 to detect the pressure of the discharged water, as in this embodiment, and send the detected pressure to the control device 20 to appropriately control the discharged water amount adjustment device 13, etc. It is.

Note that the detector 1 in the sand surface detection device 16
The numbers of 6A, 16B, and 16C are not particularly limited, and the detection method is not limited to this embodiment.

In addition, after the sandbag pillar is formed as described above,
The process of removing the casing 2 leaving only the sandbag column is the same as in the conventional method.

Therefore, if the present invention is applied to the underwater pack drain construction method, it becomes possible to create sandbag pillars of good quality with no sand particles, and the sandbag pillar creation device can be automated by a control device, so unmanned operation is possible. This has the effect of reducing personnel costs.

In particular, the present invention has the advantage that it is possible to construct sand bag pillars at high speed, and even in that case, it is possible to construct drains of good quality and uniformity.

[Brief explanation of drawings]

Figure 1 is an overall layout of a sand bag pillar creation device to which the sand bag pillar automatic creation method in the underwater pack drain construction method of the present invention is applied; Figure 2 is an enlarged side sectional view of the vicinity of the sand surface detection device in Figure 1; FIG. 3 is a plan view of the detector of FIG. 2. DESCRIPTION OF SYMBOLS 1... Soft ground, 2... Casing, 3... Sand bag, 8... Supply sand amount adjustment device, 11... Supply water amount adjustment device, 13... Discharge water amount adjustment device, 14...
Drain pipe, 15...Sand surface creation part, 16...Sand surface detection device, 16A, 16B, 16C...Detector, 20
...Control device, P...Underwater pack, S...Sand, W
……water.

Claims (1)

[Claims] 1. A casing is driven into soft ground such as the seabed, and while the water filling the casing is discharged through a drain pipe, the sand bag containing the sand and water inside the casing is lowered into the casing to form a sand bag pillar. In the underwater pack drain construction method, which creates sandbag pillars in soft ground such as the seabed, the casing etc. are removed leaving only the sandbag pillars. By detecting and controlling the amount of sand and water introduced into the sand bag and the amount of water discharged from the casing through the drain pipe so that the sand surface is always within a predetermined range, A method for automatically creating sandbag pillars in an underwater pack drain construction method, which is characterized by creating sandbag pillars at an arbitrary speed.