JP3948641B2 - Automatic control method for mud pressure shield drilling - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a mud pressure shield excavation method in which an additive is added to the face when the ground is shielded, and the earth excavated from the face and the excavated earth mixed with the additive are discharged to the outside of the well. The present invention relates to an automatic control method.
[0002]
[Prior art]
Conventionally, as an automatic control method for shield excavation of the ground, for example, an automatic control method for muddy water pressure shield excavation is known. In this automatic control method, the excavated earth and sand are fluidly transported by slurry, and automatic excavation with respect to a set value is mainly performed with excavation and soil removal being automated. Furthermore, the automatic direction control of this excavation method automatically measures the position of the shield excavator, selects a jack pattern by fuzzy reasoning, etc., and automatically propels the jack. Also, the automatic excavation management of this excavation method is to centrally manage the excavation state by converting the automatic survey results and the data of the excavation state and transmitting them to the center.
[0003]
As another shield tunnel automatic control method, for example, an automatic operation control method (Japanese Patent Laid-Open No. 6-73978) of an earth pressure shield machine is known. This automatic operation control method inputs various measurement data necessary for shield excavation such as earth pressure, shield jack speed and stroke, earthing screw rotation speed and rotation load, cutter rotation speed and rotation load into a computer, and inputs them. Multivariate analysis of the measured data is performed to calculate the management numerical value of the required control items of the shield machine, and this numerical value is output as a management value signal to the operating device of the shield machine to automatically start the operation of the shield machine At the same time, the standard deviation value of each control item is calculated from the analysis result, the control width of each control item is set, and a control signal is transmitted so that the control machine is operated within the control width to automatically operate the shield machine. It is intended to be controlled.
[0004]
[Problems to be solved by the invention]
However, the automatic control method of the muddy water pressure shield excavation is subject to automation of excavation and earth removal, and automatic excavation with respect to the set value is the main, changing the set value corresponding to various grounds and excavating I could not do it.
[0005]
On the other hand, the automatic operation control method for earth pressure shield machines is automated mainly for pressure (load) management in the rotation of cutters and screws, opening and closing of the earth discharge gate, etc., but it corresponds to the stability of the ground. No automatic control has been implemented to increase the excavation speed actively for automatic excavation. This is due to the fact that there are many constructions under difficult ground conditions and the complexity of excavation work.
[0006]
It is an object of the present invention to enable automatic excavation by actively increasing the excavation speed in accordance with the stability of the ground in addition to aiming to stabilize the face and reduce the mechanical load in the mud pressure shield excavation automatic control method. It is a thing.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention digs by adding an additive to the face when shield excavating the ground, and excavates the earth and sand excavated from the face and the additive to mix the excavated earth and sand of the face. In an automatic control method for mud pressure shield excavation that accumulates later and discharges the excavated earth and sand while maintaining the earth pressure, when the ground is stable, the earth pressure is kept within a predetermined pressure range. Then, the excavation speed is positively increased, and when the ground is unstable, the excavation speed is adjusted so that the earth pressure falls within a predetermined pressure range.
[0008]
By adding an additive to the face, the ground is prevented from collapsing and a water stop effect is brought about. Furthermore, the additive penetrates between the soil particles and gravel of the face regardless of the presence or absence of cobblestone or the like due to its fluidity, and reduces the internal friction of the ground and reduces the excavation resistance when the cutter acts. When the ground is stable, the excavation speed can be positively increased by keeping the earth pressure within a predetermined pressure range. When the ground is unstable, the earth pressure is within a predetermined pressure range, so that the earth can be safely and stably digging at the optimum digging speed at this time.
[0009]
Further, in the mud pressure shield drilling automatic control method, the additive material includes fine particles generated by crushing siliceous aqueous jelly having a silicon dioxide content of 1 to 60% by weight, and between these fine particles. It is a siliceous paste whose main component is a liquid that intervenes and has fluidity throughout.
[0010]
By using the siliceous paste as an additive, in addition to the action of the automatic control method of the mud pressure shield excavation, the water stoppage of the face and the water retention of the excavated earth and sand are further improved, and the gravel ratio and water content ratio of the ground are improved. Even if fluctuates, it remains almost unchanged. As described above, the water stoppage of the face is improved, thereby reliably preventing fear of water erupting from the face. By improving the water retention capacity of the excavated earth and sand, the excavated earth and sand becomes a very coherent property. Therefore, the present mud pressure shield excavation automatic control method can cope with various soils, improves the excavation efficiency and reduces the cost. In addition, the problem of soil pollution is eliminated. Furthermore, stable fluidity of the excavated sediment is obtained, the passage resistance passing through the addition line to the face is reduced, and the passage resistance in the pumping pipe for pumping the excavated sediment out of the mine is reduced to discharge the excavated sediment. To make it easier.
[0011]
Furthermore, in any one of the above mud pressure shield excavation automatic control methods, the addition of the additive is performed so that the ratio (addition rate) of the additive to the excavated earth and sand becomes a preset value. . It is easy to control the amount of additive material in addition to the action of any of the above mud pressure shield drilling automatic control methods by determining the addition rate to the optimum value for the excavated sediment and adding it at that ratio And the excavation speed can be maintained at a high value.
[0012]
And in one of the previous mud pressure shield drilling automatic control methods, the addition of the additive is to adjust the ratio (addition rate) of the additive to the excavated earth and sand to improve the drilling speed. It is. When the quality of the ground changes, by adjusting the addition rate to match the quality of the ground, in addition to the action of any of the previous mud pressure shield drilling automatic control method, it corresponds to various ground The excavation speed can be increased.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of an automatic control method for mud pressure shield excavation according to the present invention will be described in detail based on the drawings.
[0014]
FIG. 3 is a cross-sectional view of a principal part showing an optimum shield machine together with the ground for applying the mud pressure shield machine automatic control method according to the present invention. The mud pressure shield digging is carried out by adding an additive that prevents the ground 63 from collapsing and also has a water stop effect to the face 62 of the shield machine 51 that shields the underground ground 63 and excavates from the face 62. The excavated sediment 60 is discharged out of the mine. The additive material is added to the face 62. At this time, the earth and sand excavated from the face 62 are mixed, and the excavated earth and sand 60 in which the earth and the additive are mixed is discharged by being pumped to the outside as it is.
[0015]
The additive is supplied from a ground additive supply plant (not shown) to the face 62 through a long addition line (not shown) by a pump. A relay pump is provided in the addition line as necessary.
[0016]
The surface plate 53 provided with the face cutter 52 of the shield machine 51 is provided with a plurality of additive addition ports. An earth pressure chamber 55 is provided on the rear side of the face plate 53 (on the side opposite to the face ground), and an earth pressure gauge 57 is installed in the earth pressure chamber 55. A ribbon screw 56 is provided continuously with the earth pressure chamber 55, and a rear part of the ribbon screw 56 is a sand plug zone 58. Reference numeral 59 denotes a discharge gate. The earth pressure chamber 55 is filled with excavated earth and sand 60 excavated from the face 62 and mixed with the additive. The excavated earth and sand 60 includes a large amount of cobblestone 61, but a belt conveyor (not shown) connected to the earth discharging gate 59 and an underground hopper (not shown) provided on the lower side. And it is discharged to a ground hopper outside the mine via a pressure feed pipe by a pressure feed pump.
[0017]
In the mud pressure shield drilling, siliceous paste is used as an additive. As the siliceous paste, for example, those disclosed in Japanese Patent Application Laid-Open No. 9-88475 previously disclosed by the present applicant can be suitably used. This siliceous paste uses a siliceous aqueous jelly having a silicon dioxide (SiO ₂ ) content of about 1 to 60% by weight. However, the siliceous paste is not used as it is, but fine particles produced by crushing, and these fine particles It is mainly composed of a liquid that is interposed between particles and has fluidity as a whole.
[0018]
The particle size of the fine particles formed by crushing the siliceous water-based jelly is changed according to the soil quality of the ground to be excavated. It can respond to. When the main particle is more than 300 μm, the fluidity is lowered, and therefore, it is preferable that the particle size of the fine particles is mainly about 300 μm or less. When the content of SiO ₂ is outside the range of about 1 to 60% by weight, the siliceous aqueous jelly is not easily formed into a siliceous paste having the above properties, so the content of SiO ₂ is about 1 Within the range of ˜60 wt%, preferably 3˜30 wt%.
[0019]
Further, the siliceous paste can be defined from the viscosity value without defining from the particle size of the fine particles. The viscosity is about 50 cps to 1 million cps. By using this paste, the same action as described above can be obtained. Siliceous paste in this viscosity range exhibits thixotropic properties. Here, the viscosity is measured at a temperature of 20 ° C. with a B-type viscometer at a rotor speed of 12 rpm.
[0020]
The siliceous aqueous jelly used in the present embodiment is obtained by adding various acids and salts such as sulfuric acid, hydrochloric acid, acetic acid, citric acid, sodium chloride, magnesium sulfate to an aqueous solution of water-soluble silicate such as water glass. It is done.
[0021]
As the liquid constituting the siliceous paste, water or an aqueous solution or 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. The siliceous aqueous jelly itself contains water. If the jelly is crushed as it is, a part of the water taken into the jelly is released to the outside. Some types of siliceous aqueous jelly can give the paste the necessary fluidity with only the freed water, ie, no additional liquid. When the amount of water released to the outside by crushing is not enough, the liquid is added. The liquid such as water is interposed between the fine particles so as to prevent the recombination thereof, whereby a stable fluidity of the paste can be obtained.
[0022]
Further, the siliceous paste may contain an optional component such as a slurry, a polymer water-absorbing agent, a water-soluble polymer and the like in addition to the crushed fine particles.
[0023]
Moreover, you may use what was further submitted by this applicant etc. as a siliceous paste (Japanese Patent Application No. 8-268159, filed on October 9, 1996). This siliceous paste, like the siliceous paste, flows between the fine particles produced by crushing siliceous aqueous jelly having a silicon dioxide content of 1 to 60% by weight, and flows between these fine particles. And a polyacrylic acid salt having a molecular weight of 2 million to 30 million added thereto and 0.01 to 10 kg / m ³ .
[0024]
As the polyacrylate, sodium polyacrylate, potassium polyacrylate, and ammonium polyacrylate are suitable. Particularly preferred is sodium polyacrylate. The polyacrylate may be a copolymer of sodium acrylate or the like and acrylamide or the like. Moreover, if the molecular weight of polyacrylate is usually 2 million to 30 million, it can cope with almost all ground. In particular, the range of 5 million to 20 million is stable in terms of effect. The addition amount of the polyacrylate to the siliceous paste may be 0.01 to 10 kg / m ³ for achieving the above object. Further 0.3~2kg / m ³ ranges purposes achieve good, particularly the range of 0.5~1kg / m ³ is stable.
[0025]
The performance of the siliceous paste is improved by adding 0.01 to 10 kg of polyacrylate having a molecular weight of 2 million to 30 million per 1000 liters of the siliceous paste. In other words, the water resistance of the face and the water retention of the excavated earth and sand are improved as compared with the case where no polyacrylate is added. Moreover, it remains stable even if the ground gravel rate and water content change. Thus, since the water retention of excavated earth and sand improves, this excavated earth and sand becomes a very good property. Such a property improvement can surely prevent water from being ejected from the face. As a result, for example, siliceous paste used in sand layers and gravel layers with a gravel rate of 70% or less should be used for excavation of gravel layers mixed with cobbles with a gravel rate of 70% or more by adding the polyacrylate. Is possible. In particular, even if the amount of polyacrylate added is increased or decreased, the water retention is almost unchanged and stable.
[0026]
Therefore, by using this polyacrylate-added siliceous paste as an additive, the moisture content and gravel ratio of the ground for shield excavation, that is, the ground such as sand, gravel, and cobblestone layers rich in groundwater. Even if there is a large fluctuation, etc., the excavation can be continued as it is without replacing with a siliceous paste having other performance, so that the excavation efficiency can be improved and the cost can be reduced.
[0027]
By the way, the automatic control method of the mud pressure shield excavation according to the present embodiment uses the previous siliceous paste as an additive in the mud pressure shield excavation described with reference to FIG. 3, and the ground 63 to be excavated is stable. In such a case, the earth pressure in the earth pressure chamber 55 is kept within a predetermined pressure range to actively increase the excavation speed, and when the ground 63 is unstable, the earth pressure is set within a predetermined pressure range. Adjust the excavation speed to fit. Further, the additive is added so that the ratio of the additive to the excavated earth and sand (addition rate) becomes a preset value, or the ratio of the additive to the excavated earth and sand (addition) The rate is adjusted to improve the excavation speed.
[0028]
By using siliceous paste as an additive, it penetrates between the soil particles and gravel of the face regardless of the presence or absence of cobblestone, etc. due to its fluidity, reducing the internal friction of the ground when the cutter acts and digging Reduce resistance. When the ground is stable, the earth pressure is kept in a predetermined pressure range and the excavation speed is positively increased. When the ground is unstable, the earth pressure is kept within a predetermined pressure range. Therefore, it is possible to dig at the optimum digging speed at this time stably and stably.
[0029]
Furthermore, the additive of siliceous paste improves the water stoppage of the face 62 and the water retention of the excavated earth and sand 60, prevents the ground 63 from collapsing and brings about a waterstop effect. Moreover, even if the gravel rate and water content ratio of the ground 63 fluctuate, the stability remains almost unchanged. As described above, the water stoppage of the face 62 is improved, so that fear of water squirting from the face 62 is surely prevented. By improving the water retention capacity of the excavated earth and sand 60, the excavated earth and sand becomes a very well-organized property. Therefore, the present mud pressure shield excavation automatic control method can cope with various soils, improves the excavation efficiency and reduces the cost. In addition, the problem of soil pollution is eliminated. Furthermore, stable fluidity of the excavated sediment is obtained, the passage resistance passing through the addition line to the face is reduced, and the passage resistance in the pumping pipe for pumping the excavated sediment out of the mine is reduced to discharge the excavated sediment. To make it easier.
[0030]
By determining the addition rate to an optimum value for the excavated earth and sand and adding it at that ratio, the amount of the additive can be easily controlled, and the excavation speed can be maintained at a high value. And when the quality of the ground changes, the excavation speed can be increased corresponding to various grounds by adjusting the addition rate according to the quality of the ground.
[0031]
Here, the types of ground include silt layers, sand layers, and gravel layers, but the stability can be roughly determined by the uniformity coefficient Uc. In general, soil with Uc of 4 to 5 or less can be said to be ground with poor particle size distribution and low stability, and soil with 10 or more can be said to have good particle size distribution and high stability. The uniformity coefficient Uc is a value defined by Uc = D ₆₀ / D ₁₀ with particle diameters D ₆₀ and D ₁₀ (effective diameters) corresponding to the passing mass percentage of 60% and 10% of the particle size accumulation curve, respectively. Yes (soil test method-2nd revised edition-edited by Japan Society for Geotechnical Engineering).
[0032]
In addition, the ground where it is difficult to stabilize the face (large disintegration) has the following characteristics.
[0033]
(1) Fine particle content (particle size of about 0.074 mm) is 10% or less ( ² ) Water permeability coefficient k = (1/10 ² ) cm / sec or more ( ³ ) Water pressure 0.5 to 0.7 kgf / cm ² or more This mud pressure shield digging automatic control method can be applied to the ground where it has been difficult to stabilize the face as described above and a wide ground up to about 60% gravel rate, especially the sand layer is the uniformity coefficient Uc It is possible to target those having a uniform grain size of less than 10, which can cope with changes in soil conditions of various types of ground and minimize the change factors.
[0034]
Furthermore, in the automatic control method of the mud pressure shield excavation, the addition of siliceous paste to the face 62 is added from the addition line so that the earth pressure falls within a predetermined pressure range, and the amount added is effective for the ground. It is performed using the porosity or the porosity as a guide, and adjusted so that the excavated soil 60 is improved into a plasticized soil in a uniformly mixed state. Predetermined pressure range earth pressure, i.e. the range of management soil pressure is, for example, ^{1.5kgf / cm 2 ~2.0kgf / cm 2} . When the management earth pressure is less than 1.5 kgf / cm ² , the pressure is too low, the water stoppage is inferior, and the ground may be collapsed. When the earth pressure exceeds 2.0 kgf / cm ² , the pressure is too high, which is uneconomical such as unnecessary failure of the apparatus and increase in equipment cost.
[0035]
The addition rate of the siliceous paste is set to a preset value, but is set in a range of 5 to 40% by volume with respect to earth and sand to be excavated, and a range of 10 to 30% by volume is particularly preferable. When the addition rate is less than 5% by volume, the water stoppage of the face and the water retention capacity of the excavated sediment are inferior, and the passage resistance in the addition line to the face and the pressure resistance of the excavated sediment to the outside of the pit are large. Makes adding and discharging difficult. When the addition rate exceeds 30% by volume, the water stoppage of the face begins to be inferior and the fluidity of the excavated earth tends to be high, but when the addition rate exceeds 40% by volume, the amount of additive However, the water stoppage of the face is inferior, and the fluidity of the excavated earth is too high, making it difficult to handle due to leakage or the like, and there are many additives and it is uneconomical.
[0036]
FIG. 1 is a schematic diagram illustrating an embodiment of an automatic control method for mud pressure shield excavation according to the present invention. Automatic control of mud pressure shield digging starts from start 1 and measures the cutter pressure of the shield digging machine at cutter pressure 2. If the cutter pressure is high in the cutter pressure determination 3, the additive is added in additive additive 4, and the cutter pressure is measured again. If the cutter pressure is appropriate in the cutter pressure determination 3, the additive is added so as to have a preset addition rate, for example, 15% by volume, with the additive addition 5.
[0037]
Next, the process proceeds to additive pressure judgment 6 for the additive. When the addition pressure of the additive is not within the specified pressure range, the addition pressure is adjusted by the addition pressure increase / decrease 7 and the addition pressure is determined again. When the addition pressure is within the specified pressure range, the process proceeds to the next earth pressure determination 8. When the earth pressure determination 8 is not within the predetermined pressure range, the earth pressure determination is performed again by performing screw rotation speed control, additive material adjustment, and the like. When the earth pressure is in a predetermined pressure range, the process proceeds to the next screw rotation determination 10. If the screw rotation speed is not within the specified range, the amount of additive is adjusted by the additive adjustment 11 and the screw rotation determination 10 is performed again. The range from the cutter pressure measurement 2 to the screw rotation determination 10 corresponds to the operation preparation operation.
[0038]
Next, when the screw rotation speed is within a specified range, the process proceeds to the gate opening 12 to adjust the opening degree of the earth discharging gate 59. Next, the jack speed is adjusted by the jack propulsion 13. After the jack speed is adjusted, the jack speed is adjusted by the jack speed adjustment 15 so that the jack pressure falls within a specified range in the jack pressure determination 14. After adjusting the jack speed, the earth pressure in the earth pressure chamber 55 is adjusted by adjusting the amount of the additive and the screw rotation speed in the earth pressure adjustment 16. The range from the gate opening 12 to the jack pressure determination 14 described above corresponds to the operation immediately before the operation.
[0039]
If the jack pressure is within a specified range, the end determination is made with the excavation stroke 17. If the excavation stroke does not reach the specified value, the operation is continued and the earth pressure control system 18 is shifted to. The earth pressure control method 18 automatically or automatically selects the speed improving type or the face stable type according to the stability of the ground, and automatically controls each type.
[0040]
The speed-enhanced control is selected when the ground is stable and actively increases the excavation speed by keeping the earth pressure within a predetermined pressure range. At this time, when the earth pressure is low, the excavation speed is increased, and when the earth pressure is high, the excavation speed is maintained to increase the amount of soil discharged. For this purpose, the screw rotation speed, the earthing gate opening degree, etc. are adjusted. When the screw speed, earthing gate opening, etc. are the limits, the excavation speed is reduced.
[0041]
Face stable control is selected when the ground is unstable, and the excavation speed is adjusted so that the earth pressure falls within a predetermined pressure range. At this time, the excavation speed is maintained when the earth pressure is small, and the excavation speed is decreased when the earth pressure is large. At this time, the screw rotation speed, the earthing gate opening degree, etc. are adjusted.
[0042]
While controlling by the earth pressure control system 18, the cutter pressure is checked while adjusting the screw speed, the jack pressure while adjusting the jack speed, and the addition rate by adjusting the number of rotations of the screw by the operation code 19. The propulsion stroke end determination 17 is performed again.
[0043]
When it is determined in the propulsion stroke end determination 17 that the propulsion stroke has reached a predetermined value, the operation shifts to an operation end operation 20 where jack off, earth pressure check (additive adjustment, propulsion adjustment), gate off , Screw off, cutter off and additive material off are performed, and the propulsion end 21 is set. Next, the segment assembly 22 assembles a segment for the next excavation and returns to start 1 again. The range from the propulsion stroke end determination 17 to the operation end operation 20 corresponds to the operation in operation.
[0044]
In addition, the mud pressure shield excavation automatic control method of the present embodiment has a constant monitoring function associated with equipment protection. Normally, the excavation operator constantly monitors the excavator so that it does not overload each device of the shield excavator. With regard to mechanical overload, each shield machine can detect an overload abnormality independently. In this system, the overload occurrence of each device is managed by a predetermined management value, and the cause of the overload occurrence is deleted. Specifically, the following monitoring is performed.
[0045]
1) Screw pressure monitoring: When the screw pressure exceeds the control value, the screw speed is reduced to protect the screw power unit.
[0046]
2) Jack pressure monitoring: When the jack pressure (thrust) exceeds the control value, the jack speed is reduced to protect the jack pressure power unit.
[0047]
3) Cutter pressure monitoring: When the cutter pressure (torque) exceeds the control value, increase the amount of additive material or reduce the jack speed to protect the cutter pressure power unit and cutter face plate.
[0048]
Furthermore, the automatic control method for mud pressure shield excavation according to the present embodiment is not limited to earth pressure stability control during excavation, but also automates one-ring excavation work itself for full automation. One-ring excavation work starts from the start of various units, and the initial movement state> Various equipment adjustments until stable excavation> Control during excavation (monitoring)> Digging stop operation by one-ring excavation, all of which are automated (one-button operation) (Sequential control)).
As an object to control,
1) Analog: Jack speed, additive addition and amount, screw rotation speed, gate opening 2) Digital: Start / stop of various power units, jack push / pull / select (extraction direction control), cutter rotation speed / direction, screw rotation Number / Direction, Gate Opening FIG. 2 is a schematic diagram for explaining the face stable control in FIG. When the mud pressure shield digging 30 is performed, it is a diagram showing what problems and phenomena 31 exist for each of the following factors {circle around (1)} to {circle around (5)}, and what countermeasures and examination items 32 are. These problems and phenomena can be applied by solving them with countermeasures and considerations.
[0049]
▲ 1 ▼ Sediment uptake: cobblestone and gravel treatment ▲ 2 Sediment fluidity: excavation to earth removal ③ Sediment water stoppage ▲ 4 ▼ Face stability ▲ 5 ▼ Drilling management: earth pressure, cutter pressure, speed , Propulsion, excavated soil volume, etc. [0050]
【The invention's effect】
According to the mud pressure shield drilling automatic control method of the present invention, in the mud pressure shield drilling automatic control method, the face can be stabilized and the mechanical load can be reduced, and the drilling speed can be positively adjusted according to the stability of the ground. It is possible to dig up and dig up automatically.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining an embodiment of an automatic control method for mud pressure shield excavation according to the present invention.
FIG. 2 is a schematic diagram for explaining the face stable control in FIG. 1;
FIG. 3 is a cross-sectional view of a principal part showing an optimum shield machine together with the ground for applying the mud pressure shield machine automatic control method according to the present invention.

Claims (3)

An additive is added to the face when shield excavating the ground, and the excavated earth and sand mixed with the additive excavated from the face is accumulated in an earth pressure chamber after the face, and the soil is collected . In the automatic control method of mud pressure shield digging that discharges the excavated earth and sand through the discharge gate while maintaining the earth pressure in the pressure chamber ,
The additive mainly includes fine particles produced by crushing siliceous aqueous jelly having a silicon dioxide content of 1 to 60% by weight, and a liquid that is interposed between these fine particles and has fluidity as a whole. It is a siliceous paste as a component,
When the ground is stable, speed-enhancing control is performed, and when the ground is unstable, cutting edge stable control is performed,
The speed-enhanced control increases the excavation speed when the earth pressure is smaller than a predetermined set pressure range so that the earth pressure falls within the set pressure range, and the earth pressure is lower than the set pressure range. When it is large, the excavation speed is maintained as it is, and the amount of earth discharged through the earth discharging gate to the outside of the earth pressure chamber is increased so that the earth pressure is within the set pressure range,
When the earth pressure is smaller than a predetermined set pressure range, the cutting edge stabilization type control maintains the excavation speed and reduces the amount of earth discharged through the earth gate to the outside of the earth pressure chamber. A mud pressure , wherein the earth pressure falls within the set pressure range, and when the earth pressure is larger than the set pressure range, the excavation speed is reduced so that the earth pressure falls within the set pressure range. Automatic control method for shield drilling. According to claim 1, wherein the additive material includes wherein the siliceous paste as a main component, and further molecular weight of 2,000,000 to 30,000,000 of polyacrylate and 0.01 to 10 / m ³ addition Automatic control method of mud pressure shield drilling.   3. The mud pressure shield tunneling according to claim 1, wherein the additive is added so that a ratio (addition rate) of the additive to the excavated earth and sand becomes a preset value. Automatic control method.

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