JPS6191280A - Grout for soil pressure resistant shielding - Google Patents

Abstract

PURPOSE:To provide the titled grout consisting of an aqueous soln. of CMC, alum and a metal salt such as aluminum acetate, which forms cellulose glycolic acid salt in gel form when mixed together and poured into ground, is inexpensive and has high working efficiency. CONSTITUTION:An aqueous soln. of CMC and a metal salt such as alum and aluminum acetate which causes gelation of CMC are sent under pressure through separate pipes and are made to join near the pouring hole of a cutter chamber for mixing and formation of cellulose glycolic acid salt in gel form having a viscosity of 5,000-100,000cp. A soil pressure resistant grout for shielding consisting mainly of the above high-viscosity product is mixed with excavated soil and sand and the mixt. in gel form resists soil pressure and water pressure of working face.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the improvement of additives for earth pressure system 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 involves feeding additive materials from the ground through piping into a cutter chamber inside the shield using a pressure pump, and then injecting and kneading this into the earth and sand cut by a cutter head. This is a method to stabilize the face by changing the properties of the earth and sand, ensuring fluidity and water-stopping properties of the earth and sand.

Therefore, in this type of construction method, the properties of the additive itself play an extremely important role, and while the stability of the face is a matter of course, there are also other factors such as feeding it into the cutter chamber, pouring it into the cut soil, and mixing it. This had a significant impact on the content and scale of equipment and facilities that are essential to the process.

Conventionally, additives have generally been mainly clay, but bentonite, CMC, or water-absorbing polymers have also been used.

[Problem that the invention seeks to solve]

However, although these additives are of course appropriate from the point of view of stability of the face, they are used in extremely large amounts, have a relatively high specific gravity of 1.3 to 1.5, and have a low viscosity. Because it has a relatively high viscosity of 5,000 to 9,000 CP, a special mixer must be used, and the pressure bomb from the ground is also high, and the piping itself is relatively large and nice. However, it is inevitable that the equipment and equipment would inevitably become larger and more complex, which would cause serious problems in terms of workability. Coupled with the fact that the amount of electricity consumed is enormous, it has extremely unfavorable disadvantages from an economic point of view.

Therefore, the purpose of this invention is not only to be able to create mud with a predetermined property necessary for stabilizing the face, but also to significantly improve the work efficiency of the shield construction method, which was unprecedented in the past. The present invention aims to provide a Tonosho-based shielding additive that is economical as well.

[Means for solving problems]

In order to achieve the above object, the present invention employs an additive whose main component is gelled cellulose glycolate, which is produced by the reaction between an aqueous solution of CMC and a metal salt such as alum.

In other words, since conventional additives were press-fitted into the cutter chamber through piping after being adjusted on the ground, the properties of the additives directly affect the content or scale of above-ground and underground equipment or sensitive materials. It was to be decided.

In this respect, the present invention dramatically changes the properties of the additive depending on whether or not it reacts when it is actually injected into the chamber, and before injection, it has properties that are extremely advantageous for achieving the object of the present invention in an unreacted state. After pouring, the clay reacts and becomes mud that is sufficiently applied to stabilize the face and exhibits its original properties.

That is, before injection, the additive material is made up of multiple independent components consisting of an aqueous solution of CMC and a metal salt such as alum, each having properties of relatively low density and low viscosity compared to conventional materials, These reaction products are present in the cutter chamber after being pumped, such as s, ooo
It can be made into an additive material whose main component is a single gel-like cellulose glycolate having an extremely high viscosity of ~100,000 cP.

Therefore, when using this type of additive, for example, an aqueous CMC solution prepared on the ground and a metal salt for gelling are pumped through separate pipes and brought together near the injection port of the chamber. 000 ~100.
A method may be adopted in which a '7' AJ-shaped substance of 000 cP is injected into the tea chamber. It goes without saying that the method of use is not limited to the above-mentioned example and can be adopted as appropriate.

The gel-like cellulose glycol [i] injected into the chamber has a relatively low specific gravity compared to conventional ones, but has a significantly higher viscosity, so it can be applied in a relatively small amount compared to conventional ones. In addition, it is possible to reliably repair points with low specific gravity and build a stable face with 1!7.
There are many things that can be done.

Moreover, since gel-like cellulose glycol FIQ W is stable in alkali, even if it is mixed with backing cement, for example, it will not cause a decrease in viscosity.

By the way, in addition to alum, aluminum acetate, barium chloride, and the like are suitable as a full-strength salt, but in short, any metal salt that can gel CMC can be used.

〔Effect of the invention〕

As described above, this invention employs an additive material whose main component is gelled cellulose glycolate, which is produced by a reaction between a CMC aqueous solution and a metal salt such as alum. At the same time, it has become possible to adopt a method that can separate the unreacted process and the reactive process.

Therefore, in the material adjustment stage such as mixing, it is no longer necessary to prepare a special mixer as in the past, and a regular mixer can be used. It is no longer necessary to use a pressure pump. Furthermore, after the reaction compared to the unreacted state, a gel state with a significantly higher viscosity appears (1!7), which is approximately i/Too~1 compared to the conventionally required human clay.
．． ．． Since it is possible to sufficiently stabilize the face by using a very small amount of about 1500, it has been possible to reduce the amount of additive material and also to reduce the diameter of the pipe size.

In this way, the g9 Ha holiday has achieved five great labor savings compared to the past, so it has improved workability.
Economical efficiency is also improved; in addition to this, labor saving outside the membrane has a large impact on power consumption, so this method has been designed to significantly reduce power consumption. In addition to J5, we wanted to provide this type of construction method with an additive material that was far more economical.

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, and the additive is produced by a reaction between an aqueous solution of CMC and a metal salt such as alum or aluminum acetate. An additive material for earth pressure shielding, which is characterized by containing the produced gel-like cellulose glycolate as its main component.