JPS582284B2 - How to improve sludge ground - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvement of sludge ground.

In order to build roads, etc. on reclaimed ground made of water-containing mud, that is, sludge, which accumulates on the bottoms of ports, rivers, etc., it must be improved to have the required bearing capacity.

One of the conventional improvement methods involves laying a sheet on soft ground and mounding it on top of the sheet.

However, in extremely soft ground such as sludge, it is difficult to fill the sheet with soil, and in order to do so, the sludge must be exposed for a long time to dry. In the end, it would take a long time to improve the sludge ground.

The purpose of the present invention is to eliminate the drawbacks of the conventional methods, and in particular to improve the stability of sludge ground and the bearing capacity of the soil without using sheets.

The ground improvement method according to the present invention consists of placing hardenable improved soil, which has a smaller unit weight than sludge, in a layer on top of sludge ground, and the improved soil is mixed with a hardening agent or a hardening agent and lightweight timber. Consists of sludge.

According to the present invention, since the specific gravity of the improved soil is smaller than the specific gravity of the sludge, the improved soil does not sink into the sludge ground, but is placed in layers on the sludge ground, which is extremely soft. A layered hardened area is formed at the top of the ground.

Therefore, the weight of the embankment or structure provided as necessary on the hardened area is evenly transmitted to the entire area of the sludge ground via the hardened area.

This is extremely advantageous in uniformly consolidating the sludge ground.

The features of the invention will become clearer from the following description of the illustrated embodiments.

The illustrated example relates to the creation of new ground by pumping sludge from the bottom of a body of water delimited by an embankment.

As shown in FIG. 1, the sludge 12 collected by the dredging vessel 10 is discharged into the inner area of the embankment through the feed pipe 14.
accumulate.

Immediately, on the sludge ground 16 created by accumulating sludge to a predetermined level, improved soil 18 made of sludge mixed with a hardening agent is spread to cover the entire surface of the sludge ground 16 (see Figure 2). ).

In the illustrated example, the thickness of the curing agent-containing sludge or improved soil 18 is about 1 m.

The curing agent is mixed into the sludge in a mixing plant 20 connected to a feed pipe 14 extending from the dredger.

The improved soil 18 made of sludge mixed with a hardening agent is deposited in layers on the sludge ground 16 and hardens.

As shown in FIG. 3, a mound 24 is placed on the hardened improved soil layer 22, if necessary.

At this time, the improved soil made of hardened mud has lost its softness and can adequately support workers and earth-filling machines.
This soil filling work can be performed in the same way as on normal ground.

The embankment is optional, and can be removed by appropriately selecting the thickness of the improved soil layer 22.

In another embodiment of the present invention, the mixing plant 20 may use amended soil in which a curing agent and lightweight material barbs, such as Styrofoam, are incorporated into the sludge.

The unit weight of the improved soil can be further reduced by incorporating lightweight wood thorns.

The improved soil consisting of the sludge mixed with the hardening agent or the sludge mixed with the hardening agent and lightweight material must be smaller than the unit weight of the sludge of the ground 16.

As long as this condition is satisfied, the hardening improved soil discharged from the feed pipe 14 will not sink into the sludge ground 16.

Therefore, the curing agent must be selected appropriately so that the improved soil satisfies the above conditions.

In carrying out the present invention, a cement-based solidifying agent, a lime-based solidifying agent, and an asphalt-based solidifying agent can be used as the hardening agent.

According to the present invention, even if the reclaimed soil or ground is liquid like sludge, construction for reclamation or ground improvement can be performed immediately.

In addition, extremely soft mud like sludge can be used as reclaimed soil, making it possible to expand the range of its use.

[Brief explanation of the drawing]

Figures 1 and 2.3 are diagrams sequentially showing each step of the sludge ground improvement method according to the present invention. 12...Hedoro, 14...Hedoro feed pipe, 16...Hedoro ground, 18...Hardenable improved soil, 20...・・・Curing agent mixing plant,
22...improved soil layer.

Claims (1)

[Scope of Claims] 1. Improved soil made of sludge mixed with a hardening agent and having a unit weight smaller than the sludge of the ground is layered over the entire surface of the sludge deposited in an embankment. A sludge ground improvement method characterized by placing. 2. The method for improving sludge ground according to claim 1, wherein the hardening agent is a cement-based, lime-based, or asphalt-based hardening agent. 3. On top of the sludge deposited in the embankment, improve soil consisting of sludge mixed with a curing agent and a lightweight material phase, which has a smaller unit weight than the sludge on the ground, is layered to cover the entire surface of the ground. A sludge ground improvement method characterized by placing. 4. The ground improvement method according to claim 3, wherein the lightweight material phase is styrofoam.