JPS6361354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the improvement of additives for earth pressure shields that are injected and kneaded into cut earth and sand to counteract the earth pressure and water pressure of the face.

[Conventional technology]

As is well known, the earth pressure shield construction method uses a pressure pump to send additives from the ground through piping into the cutter chumper inside the shield, and injects and mixes this into the earth and sand cut by the cutter head. This is a method to stabilize the face by changing the properties of the soil and ensuring its fluidity and water-stopping properties.

By the way, most of the additives used in this type of construction method have been mainly clay and the like, which require a relatively large amount of water per unit. Although these additives can be relatively effective in terms of fluidizing the earth and sand in the shield chamber, reducing cutter torque, reducing the pumping pressure during additive material transfer, and preventing blowouts,
When the earth pressure and water pressure at the face have been completely resisted and the soil is discharged outside the chamber, the soil becomes muddy because it contains a large amount of water, which is not desirable from the viewpoint of the characteristics of the discharged soil. It wasn't something.

[Problem that the invention seeks to solve]

Therefore, conventionally, there has been no additive that can simultaneously and fully satisfy both of these contradictory and contradictory properties. Rather, the reality is that a large amount of water is used to ensure the properties necessary for original shield control.For example, in the case of additive materials, when the required water amount is reduced during the transfer stage, the pumping resistance is Due to the increase in the amount of water, forced water flow measures such as blowing water in midway through the process were sometimes taken.

Therefore, in the past, the soil was usually turned into muddy water, which had to be reprocessed separately to improve its quality, which was a significant factor in increasing costs.

Therefore, the purpose of this invention is to sufficiently and well ensure the plastic fluidization function for cut soil, which is extremely important in the shield method, and to reduce the pumping resistance, which is originally contradictory. The aim is to provide an unprecedented and completely innovative additive that can simultaneously and fully satisfy both requirements for improving the quality of residual soil.

[Means for solving problems]

In order to achieve the above object, the present invention consists of an additive material consisting of a blend of mineral slag, a foaming agent, and water.

In other words, in this invention, when mineral slag is added with a foaming agent, it becomes a paste even in a significantly smaller amount of water than before, and this paste compensates for the fine particles in the soil, resulting in almost the same level of plasticity as before. It was discovered that this method imparts fluidity to cut earth and sand.

In addition, this invention focuses on the fact that ore slag itself has the property of gradually self-hardening over a long period of time, and by utilizing this property, it promotes transformation into high-quality waste soil. It was designed to let you do so. Therefore, as mentioned above, the amount of water required to be mixed is extremely small, and together with this, an unprecedented improvement in the quality of the discharged soil has been achieved.

Furthermore, this invention employs a configuration in which air is mixed into the slag slag paste by adding a foaming agent to form a so-called slag air paste, thereby reducing the pumping pressure at the transfer stage as much as possible. .

By the way, various foaming agents can be used, but animal protein, which sucks in external air, is particularly suitable. For example, Glufoam (product name: Sun Orient Chemical) and Monocrete (product name: Daiichi Kasei)
Alternatively, Escort (product name: Manor) and Formics (product name: Hamano Industries) can be used. It goes without saying that the foaming agent is not limited to animal proteins, and other substances such as certain surfactants may also be used.

Regarding the mixing ratio of each component of the additive, for example, if you mix 300 kg of slag with 150 kg of water and 4 kg of foaming agent, the additive will contain 75%/ ^m3 of air. There is no problem as long as the blending amount and blending ratio are determined appropriately depending on the geology, site conditions, etc., such as the amount of fine particles inside.

〔Effect of the invention〕

As described above, this invention addresses the stabilization of the face by using a paste of ore slag, and improves the quality of soil removal by utilizing the unique attributes of ore slag. This issue was addressed by incorporating air into the additive. In addition, since the amount of water required per unit of ore slag itself is significantly smaller than that of conventional clay, the quality of soil removal is further improved in this respect as well.

Therefore, it was originally thought that this type of construction method could not handle the conflicting and contradictory issues of stabilizing the face and improving the quality of the soil removed, as well as reducing the pressure of pumping additives and improving the quality of the soil removed. It was possible to satisfy both simultaneously and satisfactorily, making it an unprecedented and innovative additive.

Therefore, unlike in the past, there is no need for reprocessing methods that are required to improve the quality of waste soil, and the quality improves naturally by simply discharging it as waste soil, making it easier to work with as well as economically. It turned out to be extremely good.

Furthermore, the additive material according to the present invention, like the conventional ones, also has characteristics particularly required for earth pressure shield construction methods, such as reduction of cutter torque and prevention of blowouts, and is compatible with the technology. We have been able to provide an additive material for earth pressure system shields that greatly contributes to the field.

Claims (1)

[Claims] 1. An additive for earth pressure shielding that is injected and kneaded into cut earth and sand to counter the earth pressure and water pressure of the face, characterized in that the additive is composed of a mixture of ore slag, a foaming agent, and water. Additive material for earth pressure shield.