JP3168501B2 - Shielding method for Dotan layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield method for a soil layer, and more particularly, to a soil shield method for excavating a soil layer using a mechanical shield machine equipped with a rotary cutter and discharging and transferring the excavated earth and sand. The present invention relates to a layer shielding method.

[0002]

2. Description of the Related Art Recently, a mud pressure type shield method and a muddy water type shield method have been developed as a kind of shield method preferable for excavation of a sand layer, a fine sand layer, a gravel layer and the like. FIGS. 1 and 2 show an example of a conventional mud pressure shield machine. FIG.
1 is a schematic explanatory view showing an example of equipment of a mud pressure shield machine to which a mud pressure shield method is applied, and FIG. 2 is an enlarged view of a main part of the mud pressure shield machine of FIG. The mud pressure shield machine 1 includes a kind of closed shield machine, open shield machine, etc., and injects a slurry as a drilling liquid in order to impart water impermeability and fluidity to excavated earth and sand. The construction method is applied, and the chamber 2 is formed behind the partition wall 11 provided with a cutting face or cutter 15 driven by a motor 16 on the front surface. The chamber 2 includes a stirring blade 14 for kneading the excavated earth and sand excavated by the cutter 15 and the slurry, a screw conveyor 13 driven by a motor 17 for sending the kneaded material, that is, the mud, out of the chamber 2.

In the mud pressure shield machine 1, when the excavated earth in the chamber 2 is positively pressurized by the pressurizing means, the earth pressure of the earth itself or the earth pressure due to the excavated earth may be applied. is there. The chamber 2 is provided with a slurry inlet 12 for injecting the slurry. This slurry is sent from the dispersion liquid storage tank 6 by a slurry pumping pump 19 through a slurry flow 9 to an injection pump 10 provided in the pit. Further, the amount of the slurry fed to the infusion pump 10 is adjusted by the control valve 20 via the slurry flow 9 and is injected into the chamber 2 from the slurry inlet 12. If necessary, water can be mixed, diluted and injected from the water injection pipe 7. On the other hand, the excavated earth and sand excavated by the cutter 15 is mixed with the slurry injected into the chamber 2 by the stirring blade 14, and is preferably discharged from the chamber 2; Made in mud which is preferred for processability.

[0004] The mud filled in the chamber 2 is thrust generated by the operation of the shield jack 22 to generate the mud.
A mud pressure is generated in the mud in the inside, the mud pressure is made to oppose the earth pressure and the water pressure acting on the cutter 15, and the mud pressure shield machine 1 is excavated and discharged. The mud generated by mixing the excavated earth and sand with the mud is supplied to the screw conveyor 1 disposed in the housing 23 forming a part of the chamber 2.
3 a belt conveyor 3 provided outside the chamber 2
And transported to the pit by a scrap steel wheel 21 or the like, and then carried out to the mud hopper 5 outside the mine through the excavated sediment flow 4, and the mud is transported from the mud hopper 5 to a predetermined place by the dump truck 8 or the like. Left. In the drawing, reference numeral 18 denotes a case jack.

FIG. 3 shows an example of a conventional muddy water shield machine. FIG. 3 is an enlarged view of a main part of a muddy shield machine to which the muddy shield method is applied. A sealed mechanical shield machine 1a in which a chamber 2a is formed by providing a partition 11a behind a rotary cutter 15a driven by a drive motor 16b, and feeds muddy water as a drilling liquid to the chamber 2a. A mud pipe 24 and a mud pipe 25 for discharging mud are connected, and muddy water corresponding to the underground water pressure is sent to the chamber 2a and pressurized, thereby stabilizing the face.

[0006] The earth and sand excavated by the cutter 15a is taken into the chamber 2a, mixed with muddy water fed from a mud pipe 24 by a stirring blade 14a driven by a driving motor 14b, and discharged by a mud pump. After being fluid-transported through the mud pipe 25 by the 28 and sent to the outside, it is separated into earth and sand 30 and muddy water 31 by a processing facility 29 such as a vibrating screen. The separated muddy water 31 is circulated to the adjusting tank 26 and adjusted to the required muddy viscosity, concentration and specific gravity.
For recirculation through the mud pipe 24 for use. 2b
Is a manhole for entering the chamber 2a, 22a is a shield jack, and 32 is a water injection pipe. Excess mud is dewatered by a dehydrator.

[0007] When shield excavation of the ground using the above-mentioned mud pressure shield method or muddy water shield method, a conventional method is used to avoid the problem that the excavated soil has poor fluidity and the excavated soil is clogged in a chamber or a screw conveyor. In general, a dispersant comprising a polyanionic water-soluble polymer such as CMC, polycarboxylic acid, naphthalenesulfonic acid / formaldehyde condensate in muddy water or slurry containing fine soil particle dispersion liquid such as bentonite There is a method of adding muddy water, mud, etc. to which is added.

However, according to the Dotan layer [illustration of civil terminology encyclopedia (published first edition on March 31, 1969, editor of the editorial dictionary for civil terms, Nikkan Kogyo Shimbun Publishing Office) Soil that shows great resistance to excavation is collectively called. In Japan, the Tertiary stratum corresponds to this.
In the case of large structures, piles are driven into this layer. ], The presence of consolidation clay with a low water content, such as muddy water or mud as conventionally used drilling fluid, is inadequate, and because soil is strongly sticky, frictional resistance with the cutter is large. In general, the excavation speed is about 20 mm / min as a standard, whereas the soil velocity falls to 5 mm / min in the clay layer. There is a problem that a lot of troubles occur, such as the excavated earth and sand adhering to the inside, reducing the chamber capacity and increasing the torque of the cutter.

The torque of the cutter during excavation is normally about 100 kgf / cm ² by hydraulic pressure of a hydraulic motor, and about 15 kg.
If it exceeds 0 kg weight / cm ² , it becomes dangerous area,
It stops at kg weight / cm ² . When the cutter stops, a person enters the sealed chamber from the manhole and cleans it. However, there is a problem that the shield machine stops for about one week for cleaning.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to reduce the cutter torque even when the clay collides with the soil layer, and to prevent the excavated earth and sand from adhering in the chamber. The shield for the soil layer that improves the fluidity of the excavated earth and sand, excavates the soil layer at a normal excavation speed with a mechanical shield machine equipped with a rotary cutter, and can easily discharge and transfer the excavated earth and sand It is to provide a construction method.

[0011]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems, and as a result, have solved the above problems by adding a surfactant to conventionally used muddy water or mud as drilling liquid. It has been found that the present invention can be performed and the present invention has been accomplished.

According to a first aspect of the present invention, there is provided an excavated earth and sand.
Depending on the ratio of
This is a shielding method for a clay layer, comprising adding an active agent in an amount of 20 g / m ³ or more .

According to a second aspect of the present invention, in the method for shielding a clay layer of the first aspect, the aerial surface tension of the drilling liquid is 35 dyne / cm or less.

[0014]

According to a third aspect of the present invention, in the shielding method for a clay layer of the first aspect, the main component of the surfactant is a nonionic surfactant having an HLB of 6 to 10. .

According to a fourth aspect of the present invention, in the method for shielding a clay layer of the first aspect, a drilling liquid containing a surfactant and a polyvalent anionic water-soluble polymer is injected into a cutter chamber. It is characterized by doing.

The invention according to claim 5 of the present invention is characterized in that, in the shield method for the earthen layer according to claim 1, the drilling liquid is muddy water in a muddy water shield method.

According to a sixth aspect of the present invention, there is provided the shield method for the clay layer according to the first aspect, wherein the drilling liquid is a slurry in a mud pressure shield method.

[0019]

According to the present invention, since the drilling liquid containing a surfactant well penetrates into the soil and easily deflocculates, and reduces the tackiness of the soil, Cutter torque can be reduced even if it hits the soil layer, excavated earth does not adhere to the chamber, and the fluidity of the earth excavated is improved. The excavated earth and sand can be easily discharged and transferred.

The type of the surfactant used in the present invention is not particularly limited. However, anionic surfactants have high foaming properties, and cationic surfactants are not preferred because they react with the dispersant and aggregate the excavated earth and sand. The surfactant used in the present invention is preferably a nonionic surfactant having both a hydrophilic group and a lipophilic group in the molecule, or a surfactant mainly containing this nonionic surfactant. Specifically, for example, polyoxyethylene octyl phenol, polyoxypropylene stearate, sorbitan monolaurate and the like have low foaming properties and are desirable.

The method of adding the drilling liquid containing a surfactant and the place of addition are not particularly limited. A simple device for adding a drilling liquid containing a surfactant to the chamber may be used alone, or a polyvalent anionic water-soluble material such as CMC, polycarboxylic acid, naphthalenesulfonic acid / formaldehyde condensate, etc. A surfactant may be mixed with muddy water or slurry to which a dispersant composed of a polymer has been added, and then added into the chamber by a conventional muddy water or slurry adding device. Polycarboxylic acids are preferred as dispersants because of their low toxicity. Mud or mud to be injected into the chamber has a funnel viscosity of 23
It is preferable to add and disperse a dispersant such as polycarboxylic acid so that the time is about seconds.

According to the second aspect of the present invention, the drilling liquid containing a surfactant permeates and deflocculates the soil more easily, and further reduces the adhesiveness of the soil. Can be further reduced, and the excavated earth and sand do not adhere to the chamber. When the aerial surface tension of the drilling liquid is 35 dyne / cm or more, the aerial surface tension of the drilling liquid is 35 dy because the drilling liquid does not penetrate into the soil layer.
ne / cm or less, preferably 30 dyne / cm or less,
More preferably, it is 29 dyne / cm or less.

According to the third aspect of the present invention, the surface tension of the drilling liquid in the air can be reduced to 35 dyne / cm or less. If the amount of the surfactant is 20 g / m ³ or less with respect to the drilling liquid, the air surface tension of the drilling liquid cannot be reduced to 35 dyne / cm or less. Specifically, for example, when the ratio of the excavating liquid in the mixture of the excavated soil and the excavating liquid is small (for example, when the ratio of the excavating liquid / the excavated soil is about 10 to 25% by volume), the surface activity is increased. The amount of the agent added is about 200-500g for the drilling liquid.
/ M ³ , when the ratio of the drilling liquid in the mixture of the drilled soil and the drilling liquid is large (for example, when the ratio of the drilling liquid / the drilled soil is about 30 to 50% by volume), The amount of addition is about 50 to 200 g / m ^{3 based} on the drilling liquid. Although the addition amount of the surfactant may be large, economical efficiency is deteriorated.

A nonionic surfactant having an HLB of 6 to 10,
Non-ionic surfactants of HLB 7 to 9 are preferred because they have low foaming properties and high permeability to the clay layer.

According to the present invention, the surfactant has a function of penetrating the soil well and making it easy to dig out, while the polyvalent anionic water-soluble polymer is digged. It has the effect of lowering the viscosity of earth and sand, making it easier to pulverize.By using both together, the cutter torque can be further reduced even if it hits the earthen layer, and the excavated earth and sand will adhere to the chamber. Disappears,
By improving the fluidity of the excavated earth and sand, the earthen layer is excavated at a normal excavation speed, and the excavated earth and sand can be more easily discharged and transferred.

The shield method for the clay layer of the present invention can be used in a shield method such as a muddy water shield method or a mud pressure shield method. In the mud pressure shield method, it is preferable to add a surfactant to the slurry as the drilling liquid, and in the muddy shield method, it is preferable to add the surfactant to the slurry as the drilling liquid.

[0027]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. (Example 1) In the mud pressure shield method shown in FIGS. 1 and 2, together with bentonite in a dispersion liquid storage tank 6, a polycarboxylic acid [trade name; Syntol B, manufactured by Hymo Co., Ltd., specific gravity 1.25] ± 0.05, external appearance: yellow, colorless, transparent liquid], ⁴ to 6K per m3 of mud discharged
g When preparing the added slurry, at the same time, a surfactant containing polyoxyethylene octylphenol as a main component as a nonionic surfactant [trade name: Sintol A, manufactured by Hymo Corporation, specific gravity 1.05 ± 0.05] appearance; colorless transparent liquid], against mud 1 m ³ for discharging 0.05-0.1
The slurry was adjusted by adding Kg. The slurry is sent from the dispersion liquid storage tank 6 to the injection pump 10 provided in the pit via the slurry flow 9 by the slurry pressure pump 19, and the amount of the slurry is adjusted by the control valve 20 via the slurry flow 9 to control the injection amount of the slurry. 12 into chamber 2.

The excavation speed when excavating the soil layer with the cutter 15 is about 20 mm / min as usual, and the torque of the cutter during excavation is about 100 mm as usual by the hydraulic pressure of the hydraulic motor.
kg weight / cm ² . The excavated earth and sand of the Dotan layer excavated by the cutter 15 is mixed with the above-mentioned slurry injected into the chamber 2 by the stirring blade 14, and is discharged from the chamber 2 in a preferable state, that is, a suitable fluidity and water impermeability. It was possible to obtain a mud having the same, that is, a mud which is preferable for waterproofness and residual soil treatment. There were no troubles such as the excavated earth and sand adhering to the inside of the chamber, which reduced the capacity of the chamber and hindered the discharge of earth.

(Example 2) In the muddy water shield method shown in FIG. 3, polycarboxylic acid [trade name; Sintol B, manufactured by Himo Co., Ltd., specific gravity of 1.
25 ± 0.05, appearance; yellow, colorless, transparent liquid] and ² to 4 kg of muddy water added to 1 m3 of discharged muddy water, at the same time, the main component is polyoxyethylene octylphenol, a nonionic surfactant. Surfactant [trade name; Syntol A, manufactured by Hymo Co., Ltd., specific gravity 1.05 ±
0.05, appearance: colorless transparent liquid]
Muddy water was prepared by adding 0.05 to 0.1 kg to ³ . The muddy water was supplied into the chamber 2a through the mud pipe 24 by the mud pump 27. The excavated earth and sand excavated from the clay layer by the cutter 15a is taken into the chamber 2a, and mixed with the above-mentioned muddy water sent from the muddy pipe 24 by the stirring blade 14a driven by the driving motor 14b to discharge the mud. Pump 28 for fluid transport through mud pipe 25,
Sent to the outside. Synthol B was added to the mud after the sedimentation to adjust the funnel viscosity to 23 seconds.

The excavation speed when excavating the soil layer with the cutter 15a is about 20 mm / min as usual, and the torque of the cutter during excavation is about 1 mm as usual by the hydraulic pressure of the hydraulic motor.
The weight was 00 kg / cm ² . The excavated earth and sand of the earthen layer excavated by the cutter 15a is mixed with the above-mentioned muddy water injected into the chamber 2a by the stirring blade 14a, and the chamber 2a
To a state suitable for discharge, that is, muddy water having appropriate fluidity. There was no trouble such as the excavated earth and sand adhering to the inside of the chamber 2a to reduce the capacity of the chamber or to hinder the discharge of the earth.

[0031]

EFFECTS OF THE INVENTION According to the shield method for the clay layer of claim 1 of the present invention, a drilling liquid containing a surfactant well penetrates into the clay and is easily peptized, and reduces the adhesiveness of the clay. Therefore, the cutter torque can be reduced even if it hits the soil layer, the excavated earth and sand will not adhere to the chamber, and the fluidity of the excavated earth will be improved, so that the earthen layer can be moved at the normal excavation speed. Excavation allows the excavated earth and sand to be easily discharged and transferred.

According to the method of claim 2, the drilling liquid containing a surfactant penetrates and peptizes the soil well and further reduces the adhesiveness of the soil. The torque can be further reduced, and the excavated earth and sand do not adhere to the chamber.

The amount of the surfactant to be added is 2
By setting it to 0 g / m ³ or more, the air surface tension of the drilling liquid can be made 35 dyne / cm or less. Although the addition amount of the surfactant may be large, economical efficiency is deteriorated.

The nonionic surfactants having an HLB of 6 to 10 are preferred because they have low foaming properties and high permeability to the clay layer.

According to the fifth aspect of the present invention, the surfactant is well penetrated into the soil by the soil method, and the polyvalent anionic water-soluble polymer reduces the viscosity of the excavated earth and sand. Therefore, the excavated earth and sand can be easily peptized by using both together. Therefore, the cutter torque can be further reduced even if it hits the soil layer, the excavated earth and sand will not adhere to the chamber, the fluidity of the earth and sand will be further improved, and the earthen layer will be excavated at a normal speed. And the excavated earth and sand can be more easily discharged and transferred.

The shield method for a clay layer of the present invention can be used in a shield method such as a muddy water shield method or a mud pressure shield method. In the mud pressure shield construction method, it is preferable to add a surfactant and a dispersant to the slurry for drilling, and to add the surfactant and dispersant to the slurry for drilling in the slurry shield method. .

The shield method for the clay layer of the present invention can use a conventional shield machine, is simple in construction, is economical, and has a great effect, and therefore has high industrial utility value.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of equipment of a mud pressure type shield machine to which a shield method for a clay layer according to the present invention is applied.

FIG. 2 is an enlarged view of a main part of the mud pressure shield machine of FIG.

FIG. 3 is an enlarged view of a main part of a muddy water shield machine to which the shield method for a clay layer according to the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mud pressure shield machine 1a Mud shield machine 2, 2a Chamber 2b Manhole 3 Belt conveyor 4 Excavated sediment flow 6 Dispersion liquid storage tank 7, 32 Water injection pipe 8 Dump truck 9 Sludge flow 10 Pump 11, 11a Partition wall 12 Sludge inlet 13 Screw conveyor 14, 14a Stirring blade 15, 15a Cutter 23 Housing (part of chamber) 24 Mud feed tube 25 Mud drain tube 26 Adjustment tank 29 Treatment equipment 30 Sediment 31 Muddy water

Claims (6)

(57) [Claims] 1. According to the ratio of excavated earth and sand to excavating liquid
And a surfactant for adding a surfactant to the drilling liquid in an amount of 20 g / m < ³ > or more . 2. The aerial surface tension of the drilling liquid is 35 dyne.
/ Cm or less, the shielding method for a clay layer of claim 1 characterized by the above-mentioned. 3. The method according to claim 1 , wherein the main component of the surfactant is HLB 6 to 10.
2. A non-ionic surfactant.
Shielding method for soil layer described in 4. 4. A surfactant and a polyvalent anionic water-soluble compound.
Inject drilling fluid containing polymer into the cutter chamber
The seal for the clay layer of claim 1, wherein
Do construction method. 5. The method according to claim 5, wherein the drilling liquid is used in a muddy water shield method.
It is muddy water, for Dotan layer of Claim 1 characterized by the above-mentioned.
Shield construction method. 6. The method according to claim 6, wherein the drilling liquid is used in a mud pressure shield method.
The muddy layer according to claim 1, wherein the muddy layer is mud.
Shield method.