JPH07102881A - Shield excavation method by using bubble and jelly - Google Patents

Abstract

PURPOSE:To improve the permeability to a facing by using a silicic acid type paste obtained by crushing a silicic acid type water jelly having a specific wt.% of including rate of silicon dioxide, and bubbles or a foaming agent, as a pouring material of a shield excavation method. CONSTITUTION:A shield type excavator 1 under the ground, and a pouring material feeding plant 2 on the ground are connected to a pouring line 3 through a compression pump 4, and a feeding port 8 of the pouring material is provided on the face plate 7 having the facing cutter 6 of the shield type excavator 1. Then, an earth pressure chamber 9 is provided at the near side of the facing cutter 7, a ribbon screw 10 is provided linking to the earth pressure chamber 9, a sand plug zone 12 is formed at the rear side, and the excavation muck mixed with the pouring material is filled in the earth pressure chamber 9. Then, minute particles produced by crushing a silicic acid type water jelly having about 1 to 60wt.% of including rate of silicon dioxide; a silicic acid type paste mainly of a liquid having a liquidity provided among the minute particles; and bubbles or a foaming agent; are used as a pouring material. And such a pouring material is delivered and poured to the facing through the pouring line 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a soil layer excavation method using a shield type excavator. The shield excavation method using bubbles and jelly of the present invention is used for a tunnel excavation method for preventing collapse of an excavation portion and having a water blocking effect.

[0002]

2. Description of the Related Art The mud pressure shield method is generally used for excavating a soil layer while press-fitting a slurry containing bentonite or clay as a main component, that is, an aqueous slurry as an injection material into a face to excavate a soil layer. ing. Compared with the conventional non-injection earth pressure type shield construction method, the effect is to compensate for the lack of fine grains in the ground, and by replacing it with face groundwater, the excavable target is from viscous ground to sand ground, and Has the great advantage that it can be expanded to gravel ground.

Further, as a pouring material, shaving cream-like air bubbles are injected instead of the slurry, and a bubble shield excavation method of advancing while improving the fluidity of excavated earth and sand by the bearing effect, and a high molecular water absorbent are injected. Therefore, a method of improving the water stoppage of excavated sediment and advancing is adopted.

However, when the mud pressure shield construction method is applied to the ground such as sand, gravel, and cobblestone rich in groundwater, and the injection material is made of bentonite and a slurry containing clay as a main component, the following problems occur. There is a point. That is, in the mud earth pressure shield construction method of injecting slurry, when excavating sand ground with high groundwater pressure and abundant sand or gravel ground with a gravel rate of 70% or more, due to the soil particle composition of the excavated sand, the cutting torque The rotation of the cutter is interrupted due to an abnormal rise in the soil, and the fluidity required from the earth pressure chamber for excavated soil to the soil discharge mechanism such as the screw conveyor or ribbon screw is lacking, groundwater is ejected, and counter earth pressure is generated. It often causes defects.

As measures against these, sand rich in groundwater,
For the ground such as gravel and cobblestone layers, a bubble-slurry shield excavation method has been proposed in which bubbles are mixed into sludge and injected into a face (Japanese Patent Publication No. 5-42560).

The shield excavation methods described above can maintain a stable excavation to some extent by being used appropriately according to the target ground. However, in any shield excavation method, bentonite added as an injection material, bubbles, or a polymer water-absorbing agent is mixed into the excavated shear, that is, the soil finally discharged to the outside of the mine, so that it is possible to reduce pollution. In some cases, soil removal treatment measures were necessary.

Therefore, the inventors of the present application have developed and previously proposed a shield excavation method using an injection material containing no sludge, air bubbles, polymeric water-absorbing agent, etc. (JP-A-4-343997). It is an excavation method that uses siliceous jelly (SiO ₂ ) as an injecting material, and there is no problem of soil pollution, and if it is injected and penetrated between the soil particles of the face and gravel, when the cutter acts, The internal friction of the ground is reduced to reduce excavation resistance, and the fluidity from the face to the kneading mechanism in the earth pressure chamber is improved. In addition, it is possible to push back the face ground water to the ground side of the face. Furthermore, by injecting it into the earth pressure chamber as needed, a counter earth pressure is generated in the earth pressure chamber to suppress the earth face pressure and groundwater pressure to stabilize the face and to discharge the earth pressure chamber to the outside of the mine. The liquidity of
It was possible to maintain stable excavation as good as sludge and bubbles.

[0008]

However, as a method of injecting the injection material into the face of the tunnel, it is general to send the material from the injectant supply plant installed on the ground to the face of the underground tunnel through a long introduction pipe. When siliceous jelly is used as an injection material, this jelly is an agar-like gel, and therefore the passage resistance of the introduction tube is extremely large. Therefore, there is a case where the supply to the face cannot be performed stably, and there is a problem that a considerably large-scale supply plant must be prepared for reliable delivery.

Further, even if the siliceous jelly is sent to the face, if boulders or the like are present near the supply port of the face cutter, the permeation resistance to the face rapidly increases and immediately flows back to the earth pressure chamber side. However, there is a problem in that it is difficult to maintain stable penetration of siliceous jelly into the face.

It is an object of the first invention of the present application to provide a shield excavation method capable of stably permeating siliceous jelly as an injection material into a face regardless of the presence of cobblestones.

A second object of the present invention is to supply siliceous jelly as an injecting material to the cutting face through the introduction tube with a small resistance and stably, and to stably provide the cutting face regardless of the presence of cobblestones. It is intended to provide a shield excavation method capable of infiltrating into the ground and thus greatly improving the workability.

[0012]

In order to achieve the above object, a shield excavation method according to the first invention of the present application is directed to a rotating face cutter portion, an earth pressure chamber, an agitating means for agitating soil in the earth pressure chamber, and an earth pressure. A shield for excavating a soil layer while operating a shield machine having an ejecting means for ejecting indoor soil and an injecting material introducing means for injecting the injecting material into the face, while injecting the injecting material into the face. A method of excavation, characterized in that a siliceous aqueous jelly and a bubble or foaming agent are used as the injection material.

Further, the shield excavation method according to the second invention of the present application is the method of the first invention, wherein the siliceous aqueous jelly which is a component of the injection material is a siliceous aqueous jelly having a silicon dioxide content of about 1 to 60% by weight. It is characterized by being used after being modified into a siliceous paste containing fine particles produced by crushing and a liquid interposed between these fine particles and having fluidity throughout as a main component.

[0014]

According to the first aspect of the invention, not only the siliceous aqueous jelly but also the foam or the foaming agent is used as the injecting material. Therefore, the fluidity of the siliceous aqueous jelly is caused by the inclusion of the foam or the foaming agent. As a result, the siliceous aqueous jelly injected into the face can be stably permeated into the face regardless of the presence of boulders. When this air bubble or foaming agent is mixed with the siliceous aqueous jelly in advance and sent from the siliceous aqueous jelly supply plant on the ground to the face through the introduction line, the passage resistance in that line is also reduced because of the presence of bubbles, so it is stable. Then, it becomes possible to supply it to the face.

The second invention of the present application does not use the siliceous aqueous jelly, which is one component of the injection material, as it is, but the fine particles produced by crushing and the fluidity throughout the particles by interposing between the fine particles. It uses a siliceous paste whose main component is a holding liquid. The siliceous paste formed in this way rarely returns to the original jelly due to the binding of fine particles to each other, and the whole is in a suspension state, unlike the state of jelly, it flows like muddy water. There is a nature. Here, the particle size of the fine particles depends on the soil quality of the target ground to be excavated, and further changes corresponding to the purpose of the present invention of reducing the passage resistance of the introduction pipe and improving the permeability to the face,
It can be applied to any ground as long as it has a particle size of about 300 μm or less. Due to the fluidity of the siliceous paste, the passage resistance of the introduction pipe is significantly reduced, and it becomes possible to stably supply the paste to the face. When air bubbles are mixed with siliceous paste in advance and sent from the above-mentioned injection material supply plant to the cutting face through the introduction line, the passage resistance in that line is further reduced by the presence of the bubbles, so it is more stably supplied to the cutting face. It becomes possible to do. Further, due to the fluidity of the siliceous paste and the inclusion of air bubbles, the paste and air bubbles easily permeate the face regardless of the presence of cobblestones or the like. Since the permeation of air bubbles gives a bearing effect to the face, mechanical load such as cutter pressure is reduced, and thereby the excavation speed can be increased. That is, the workability is significantly improved.

The particle size of the particles produced by the above crushing is 300 μ
When the particle size is mainly m or more, the above-mentioned fluidity is deteriorated, so it is preferable that the particle size of the fine particles is mainly about 300 μm or less. In addition, the content of SiO ₂ is about 1 to
Becomes out of the range of 60 wt%, it is hard becomes siliceous paste the properties even by crushing the jelly, SiO ₂
Content in the range of about 1 to 60% by weight, preferably 3 to
30% by weight.

Further, the siliceous paste in the second invention may be defined not by the particle size of the fine particles but by the value of clay. That is, a siliceous paste having a viscosity of about 50 cps to 1,000,000 cps has excellent fluidity, and the same effect can be obtained by using this paste. Here, the viscosity is measured at a temperature of 20 ° C. and a B-type viscometer at a rotor speed of 12 rpm. The siliceous paste in this viscosity range exhibits thixotropic properties.

[0018]

EXAMPLES The siliceous aqueous jelly used in the first invention of the present application can be easily obtained by a known method. Examples thereof include a method of adding various acids and salts such as sulfuric acid, hydrochloric acid, acetic acid, citric acid, sodium chloride and magnesium sulfate to an aqueous solution of a water-soluble silicate such as water glass. Further, a method of gelling an aqueous solution of silicic acid or an oligomer thereof obtained by decationizing an aqueous solution of a water-soluble silicate such as water glass, or a method of gelling a silica aqueous sol by a known method, etc. Can be mentioned.

The bubbles forming one component of the injection material are obtained by a known method such as mixing a gas with an aqueous solution containing a foaming agent, and have a shaving cream shape. In this case, the amount of the foaming agent added is 0.01 with respect to 100 parts by weight of water.
-50 parts by weight is standard. As the type of foaming agent,
Protein type foaming agents, higher fatty acid salts, anionic surfactants such as alkyl sulfates and alkyl sulfonates,
Nonionic surfactants such as polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, sorbitan fatty acid ester, higher amine halogenate,
Cationic surfactants such as quaternary ammonium salts, commercially available concrete AE agents such as Winsole, trade name, and Bozoris No 303A.

When the foaming agent is added directly to the siliceous aqueous jelly, the standard amount of the foaming agent is 0.01 to 50 parts by weight based on 100 parts by weight of the siliceous aqueous jelly.

The siliceous paste according to the second invention of the present application is obtained by crushing the siliceous aqueous jelly as described above by applying a physical external force sufficient to cause destruction of the jelly. Crushing to produce such fine particles can be carried out by applying strong stirring such as a homogenizer to the jelly at room temperature. As a general guideline, this vigorous stirring should be continued until the particles become fine particles mainly having a particle size of about 300 μm or less. Alternatively, it may be continued until the viscosity of the obtained paste shows about 50 cps to 1,000,000 cps.

As the liquid constituting the siliceous paste according to the present invention, water or an aqueous solution or an aqueous dispersion to which an inorganic component or an organic component is appropriately added is used as long as the object of the present invention is achieved. By the way, the siliceous aqueous jelly itself contains water, and if the jelly is crushed as it is, a part of the water taken in the jelly is released. Depending on the type of siliceous aqueous jelly, it is possible to give the paste the required fluidity only with the released water, ie without adding further liquid. The liquid is added when the amount of water released to the outside by crushing is not sufficient. This liquid such as water
The fine particles are interposed so as to prevent their recombination, whereby a stable fluidity of the paste can be obtained.

As long as the object of the present invention is achieved, the siliceous paste of the present invention comprises, in addition to the above-mentioned finely divided jelly particles,
It may also contain optional components such as sludge, water absorbent polymer, water-soluble polymer and the like. Inclusion of such optional components,
A method of mixing the paste and this optional component, in the crushing step of the jelly, a method of adding this optional component to the jelly before crushing and then crushing the jelly, or a method of adding this optional component during crushing of the jelly. Can be done by

Next, a shield excavation method according to the present invention will be described with reference to FIGS. An underground shield machine 1 and a ground injection material supply plant 2 are connected by a long injection line 3. The supply plant 2 is connected to an injection line 3 via a pressure feed pump 4. The injection line 3 may be provided with a relay pump 5 if necessary.
The face plate 7 of the shield machine 1 having the face cutter 6 is provided with a plurality of injection material supply ports 8. An earth pressure chamber 9 is provided on the front side of the face plate 7, and a ribbon screw 10 is provided in series with the earth pressure chamber 9. An earth pressure gauge 11 is provided in the earth pressure chamber 9. The rear part of the ribbon screw 10 is a sand plug zone 12,
Reference numeral 13 indicates an earth discharging gate. The earth pressure chamber 9 is filled with an excavation shear 14 excavated from a face and mixed with an injection material. The excavated shear 14 shows a large amount of boulders 15. 22 is a belt conveyor.

Example 1 A siliceous aqueous jelly and bubbles were used as an injection material. The bubbles were generated as described above, and a bubble introduction line (not shown) was communicated with the tip of the injection line 3 and the front portion of the earth pressure chamber 9 to mix the bubbles with the siliceous aqueous jelly. The target ground was a gravel layer containing boulders with a gravel rate of 70% or more. The mixing ratio of air bubbles was approximately 1: 1 by volume ratio with respect to the siliceous aqueous jelly. The bubble-containing siliceous aqueous jelly injected into the face of a gravel layer mixed with boulders with a high gravel ratio penetrated into the face steadily regardless of the presence of boulders.

When the siliceous aqueous jelly and the generated bubbles are mixed in the injecting material supply plant 2 and sent to the face through the injection line 3, the passage resistance in the line 3 becomes small, and the stable supply is achieved accordingly. I was able to.

Example 2 A siliceous aqueous jelly and a foaming agent were used as injection materials. The foaming agent was premixed with the siliceous aqueous jelly in the injection material supply plant 2 and sent to the face through the injection line 3. The sand layer and gravel with a gravel rate of 70% or less were used as the target ground. The ratio of the foaming agent was such that the mixing ratio of bubbles generated by foaming by the face was 5 to 10%. The foaming agent-containing siliceous aqueous jelly injected into the face of a sand layer and gravel having a gravel rate of 70% or less causes the foaming agent to immediately foam to generate bubbles. Stable and stable penetration of the face regardless of the presence or absence. still,
The foaming agent may be mixed in the jelly just before the face as in Example 1.

Example 3 As the injection material, the siliceous paste obtained by crushing siliceous aqueous jelly and bubbles were used. As the siliceous paste, the following pastes A, B and C were used for each board. Then, the bubbles were generated as described above, and the bubble introduction line (not shown) was made to communicate with the tip of the injection line 3 and the front portion of the earth pressure chamber 9 to mix the bubbles into the siliceous paste. The volume ratio of air bubbles is approximately 1: 1 as a standard with respect to the siliceous paste. Adjust the amount of air bubbles to increase when the ground is rich in groundwater, and increase the paste when the ground is high in boulders. It was adjusted. As a result, first, due to the fluidity of the pastes A, B, and C, the passage resistance of the injection line 3 was significantly reduced, and the long line 3 from the ground to the face could be stably fed with low resistance.
Further, the bubble-containing siliceous paste injected into the face of each plate penetrated into the face very stably regardless of the presence of boulders due to the fluidity of bubbles and paste, and the workability was greatly improved. Comparing the required time when excavating only the paste A with a cutter having a diameter of 2 m and when excavating the paste A and bubbles with respect to the ground having a gravel rate of 70% or more, 35 minutes for the paste A alone. Although it took 20 minutes for the paste A + air bubbles, the workability was obviously improved. Further, when the mechanical loads of the same two were compared, when the paste A alone was set to 1, it was 0.86 for the paste A + bubbles.

When the siliceous paste and air bubbles were mixed in advance in the injection material supply plant 2 and sent to the face through the injection line 3, the passage resistance in the line 3 was further reduced by the air bubbles, and a more stable supply was possible. It was

Example 4 As the injection material, the siliceous paste obtained by crushing siliceous aqueous jelly and the foaming agent were used. As the siliceous paste, the following pastes A, B and C were used for each board as in Example 3. The foaming agent is mixed in advance with the siliceous paste in the injection material supply plant 2 and the injection line 3
Sent to Kirito. The ratio of the foaming agent is such that the mixing ratio of air bubbles generated by foaming by the face becomes 5 to 10%, and if the ground has a lot of groundwater, it is adjusted to increase the air bubble ratio. Adjusted to increase the paste. As a result, the flow resistance of each of the pastes A, B, and C is substantially the same as in Example 3, and the passage resistance of the injection line 3 is greatly reduced, so that the long line 3 from the ground to the face can be stably fed with low resistance. I was able to. In addition, the foaming agent-containing siliceous paste injected into the face of each plate is
Since the foaming agent immediately foamed to generate bubbles, the siliceous paste stably penetrated into the face regardless of the presence of boulders due to the fluidity of the bubbles and the paste. The foaming agent may be mixed in the paste just before the cutting face as in Example 3.

Paste A The following paste A was prepared for a cobblestone-mixed gravel layer having a gravel rate of 70% or more. 15 to 30 weight of sol of SiO ₂ is used as a main material, 140 liter of this main material is mixed with 439 liter of water, and 44 liter of 5% by volume H ₂ SO ₄ is added as an auxiliary material to the mixture, and further mixed. As a hardening material, 47 liters of a solution prepared by diluting No. 3 water glass to 40% was added and mixed to obtain 670 liters of siliceous jelly. Add 330 liters of water to this and stir vigorously to make the jelly particle size 300μ.
The particles were subdivided into fine particles of m or less to obtain 1000 liters of siliceous paste as a whole.

Paste B The following paste B was prepared for the sand layer and gravel having a gravel rate of 70% or less. A sol of 15 to 30 weight of SiO ₂ is used as a main material, 105 liters of this main material are mixed with 327 liters of water, and 5 volume% of H ₂ SO ₄ is added as an auxiliary material to the mixture.
35 liters of a solution prepared by diluting No. 3 water glass to 40% was added as a hardening agent and mixed to obtain 500 liters of siliceous jelly. To this, 500 liters of water was added and vigorously stirred, and the jelly was subdivided into fine particles having a particle size of 300 μm or less to obtain 1000 liters of siliceous paste as a whole.

Paste C The following paste C was prepared for the clay soil layer. Water glass as the main material, 60 liters of this main material and water 795
1 liter was mixed with 5% by volume of H ₂ as a hardening material.
Add 145 liters of SO ₄ and mix to add 1 part of siliceous jelly.
000 liters were obtained. This is vigorously stirred, and the jelly is subdivided into fine particles having a particle size of 300 μm or less.
000 liters of siliceous paste was obtained.

[0034]

[Table 1]
Type Specific gravity Viscosity pH Paste A 1.02 800cps 7.0 Paste B 1.01 500cps 7.0 Paste C 1.03 200cps 6.5 Table 1 above shows the characteristics of each paste A to C. The shield method using a siliceous paste as a component of the injection material can be applied to a wide range of grounds from cobblestone gravel layer to sand layer and cohesive soil layer. It is preferable to use each of the pastes A, B and C shown in 1 to 3 as a guide.

The siliceous paste is injected into the face of the face or the earth pressure chamber from the line under the required pressure, and the amount of the injection is determined by taking the effective porosity or the porosity of the ground as a standard. It is adjusted to improve the plasticized soil in a uniformly mixed state of gravel.

[0036]

According to the first invention of the present application, not only the siliceous aqueous jelly but also the bubbles are used as the injecting material. Therefore, the inclusion of the bubbles increases the fluidity of the siliceous aqueous jelly, and the silicic acid injected into the face is The water-soluble jelly can be stably infiltrated into the face regardless of the presence of cobblestones.

According to the second invention of the present application, since the siliceous paste obtained by vigorously stirring the siliceous jelly and having excellent fluidity is used as the injecting material, it can be stably supplied to the face with less resistance through the introduction pipe. You can Further, due to the fluidity of the siliceous paste and the inclusion of air bubbles, it becomes possible to more stably permeate the face regardless of the presence of cobblestones, etc., and the workability can be greatly improved. Therefore, stable excavation can be maintained by the above inventions of the present application.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a shield excavation method according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a front view showing only the left half of the shield machine according to the present invention.

[Explanation of symbols]

 1 shield machine 2 silicic acid paste supply plant 3 injection line 6 cutter 8 inlet 9 earth pressure chamber 14 excavation shear

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Jun Uchida 1 722 Tsuboi-cho, Funabashi-shi, Chiba Central Research Laboratories, Nissan Chemical Industries, Ltd. (72) Masanori Muto 1 722 Tsuboi-cho, Funabashi, Chiba Nissan 1 Central Research Institute, Inc. (72) Inventor Akio Kitagawa 3-7-1 Kandanishikicho, Chiyoda-ku, Tokyo Nissan Chemical Industry Co., Ltd.

Claims (2)

[Claims] 1. A rotating face cutter, an earth pressure chamber, a stirring means for agitating the soil in the earth pressure chamber, a discharging means for discharging the soil in the earth pressure chamber, and an injecting material introducing means for injecting an injecting material into the face. A shield excavation method in which a shield type excavator provided is operated to inject an injecting material into the face, and a soil layer is excavated, wherein a siliceous aqueous jelly and bubbles or a foaming agent are used as the injecting material. A method for excavating a shield using bubbles and jelly, which is characterized in that 2. The siliceous aqueous jelly, which is a component of the injection material, according to claim 1, having a silicon dioxide content of about 1 to 1.
Use by modifying to a siliceous paste containing fine particles produced by crushing 60% by weight siliceous aqueous jelly and a liquid interposed between these fine particles and having fluidity throughout as a main component A method for excavating a shield using bubbles and jelly, characterized by: