JPS5918826A - Excavation by dredger - Google Patents

Abstract

PURPOSE:To prevent the pollution of the water area of excavation site by a method in which excavating dredging work is performed by means of a dredger having a cage housing a solid coagulant in the neighborhood of the tip of the ladder of the dredger. CONSTITUTION:A cage 3 is provided at the tip of the ladder 2 of a pump ship 1, and a solid coagulant is packed into the cage. The tip of the ladder 2 is brought down to the bottom to be excavated in water and sludge is sucked up while swingingly moving the ladder 2 bilaterally, where the coagulant is dissolved during the excavation period with the swinging movement of the ladder 2 to coagulate sludge particles in the nearby area. As the coagulant used, anionic ones, e.g., aluminium sulfate, etc., cationic ones, e.g., water-soluble anilinic resin hydrochloride, etc., nonionic ones, e.g., water-soluble urea resin, etc., and amphoteric ones, e.g., gelatin, etc., may be used. Dredging work can thus be performed without generating the pollution of the water area in and around the dredging area.

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, excavation using a pump ship or a grab ship has the disadvantage that pollutants from the excavated area are stirred up and contaminate nearby water bodies. In order to avoid such a phenomenon, construction work was carried out by surrounding the excavation and dredging area with a girder or oil fence. However, neither method was satisfactory.

The present inventor has completed the present invention as a result of various efforts to solve these conventional drawbacks.

That is, the present invention provides a dredger near the tip of the rudder and/or
Alternatively, there is a method of excavating and dredging using a dredger equipped with a grab bucket section containing a solid coagulant.

Next, the method of the present invention will be specifically explained.

FIG. 1 is a schematic diagram of a pump ship, where 1 is a pump ship, 2 is a rudder, and 3 is a part. When excavating and dredging with a pump ship, the tip of the rudder is lowered to the bottom of the water being excavated, and the rudder 2 is sucked up while swinging from side to side. At this time, in the present invention, a member 3 is provided near the tip of the ladder 2, and a solid flocculant is filled therein. In this way, the part 3 containing the solid flocculant is attached to the vicinity of the tip of the ladder 2, and the flocculant is dissolved by the swing of the ladder 2 during excavation, and the contaminant particles in the vicinity are enlarged. Can be aggregated. Cage body 3/' attached to ladder 2
As shown in Fig. 2, for example, a cylindrical shape made of iron rod 4 is used to fix the cylindrical shape of the net, and the lid 5 can be opened and closed to conveniently store the flocculant. It is set in. Connection IK!: 6, 6' for attaching to the rudder 2 is provided on the (iJl1 side) of the front body 3.

It is preferable that the flocculant 74y stored in the cage 3 be stored in a mesh-like bag 7, for example, as shown in FIG.

The flocculants used include aluminum borate, ferrous sulfate, ferric sulfate, ferric chloride, polygammaluminium chloride,
Saw machine flocculants such as polyaluminum sulfate, anionic flocculants such as sodium alginate and sodium polyacrylate, cationic flocculants such as water-soluble aniline resin hydrochloride, polyvinylpyridine hydrochloride, water-soluble urea resin,
Examples include nonionic flocculants such as polyacrylamide, amphoteric flocculants such as gelatin, and the like. For example, when these flocculants are used in combination with an anionic flocculant and a cationic flocculant, the force is 1, or the force of the above two and a nonionic flocculant is 3p4.
Use the same combination! It is preferable to use a type A flocculant together.

Note that a solid flocculant obtained by mixing an inorganic flocculant and a cationic or nonionic organic flocculant may be used.

In addition, as another method, if a front body 3 as shown in FIG. 2 is attached to the outside or inside of the frame part or bucket shell part of the grab bucket 9 provided in the grab ship 8, the same effect as in the pump ship described above can be obtained. Since pollutants from the excavation tIj can be aggregated, they do not pollute the water area in the excavation area.

[Brief explanation of the drawing]

Figure 1 is a state diagram showing the state of excavation by a pump ship, Figure 2
The figure is a perspective view of the front body, FIG. 3 is a front view of the bag filled with solid flocculant, and FIG. 4 is a state diagram showing the excavation state with a grab vessel. Patent applicant Nippon Solid Co., Ltd.

Claims (1)

[Claims] An excavation method characterized by excavating and dredging using a dredger equipped with a part containing a solid flocculant near the tip of the dredger's rudder and/or in the rub bucket part of the dredger.