JPS6140837B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention is related to the earlier applications (Japanese Patent Application No. 54-103893 (Japanese Unexamined Patent Application No. 56-28999) and Japanese Patent Application No. 54-111426 (Japanese Unexamined Patent Application No. 56-34898). The present invention relates to a face control method for a shield excavator that automatically controls the face ground on the front side of the cutter of a muddy water shield excavator so as to always stabilize it. In the shield tunneling machine, as shown in Fig. 1, muddy water is fed into the cutter chamber b by the muddy water pipe a of the fluid transport system, and the muddy water is discharged from the cutter room b through the muddy water pipe c. The face is stabilized using mud water pressure, but in this case, the mud water pressure, which is sent into cutter chamber b and contains excavated soil (sludge), is used to counteract the earth pressure of the face ground and (groundwater pressure). In order to stabilize the face by increasing the resistance (resistance), accurate stability management of the face is necessary.Therefore, conventionally, a mud water density meter d and a mud water flow rate system e are connected to the mud water pipe a, and the mud water flow rate system e is connected to the mud water pipe a. A wastewater density meter f and a wastewater flowmeter g are attached to the water pipe e, and the signals detected by these are converted into a calculator (not shown).
This calculator calculates the amount of dry sand by removing water from the water-containing excavation depth, and this calculated dry sand amount is determined in advance by comparing it with the theoretical dry sand amount calculated by soil sampling. It is checked whether the amount of excavated dry sand is within the established control standard values. However, the soil sampling described above is only
Because the survey is only carried out at 50 to 60 m intervals at the ground points near the shield excavator, the water content ratio, true specific gravity, layer boundaries, etc. that are the basis for calculating the amount of dry sand do not represent the true geology. Therefore, it is difficult to say that the actual amount of dry sand is equivalent to the actual ground mass, and for the reasons mentioned above, it is inaccurate due to large errors.
There is a drawback that accurate and stable management of the face cannot be performed. In addition, we have developed a method for stably managing the face by removing the intermediate feed/sludge water density meters d and f in Figure 1 and adding a shield jack I's propulsion speed detector. There is also a method of calculating the theoretical excavation volume value by multiplication, and controlling the value obtained by subtracting the flow rate measured by the slurry water flow meter e from the flow rate measured by the mud discharge flow meter g to become the theoretical excavation volume. However, with this method, even if the rock face collapses due to mud water pressure fluctuations in the cutter chamber b, there is no means to detect this, so no countermeasures can be taken. It is impossible to reliably stabilize the face all the time. In addition, as mentioned above, due to the mud water pressure fluctuation in the cutter room, the mud water pressure inside the room may leak to the face ground side, or groundwater may permeate into the cutter room, causing a large error in the excavation volume deviation flow rate value. It is also impossible to obtain accurate face stability from this point. [Purpose and Summary of the Invention] This invention was made as a result of intensive research in order to solve the above-mentioned various problems all at once, and its purpose is to enable the shield excavator to directly detect and measure the actual earth pressure of the face ground. The detected actual earth pressure is accurately corrected and compared with the earth pressure that stabilizes the face earth.The propulsion speed of the shield jack is controlled by the signal that is calculated, and the mud water pressure in the cutter chamber is adjusted to the earth pressure that stabilizes the face earth. The present invention proposes a face control method for a shield excavator that can reliably stabilize the ground in front of the face at all times by controlling the flow rate of feed and mud removal water to sufficiently counter the earth pressure and water pressure. [Embodiment] A preferred embodiment of the present invention will be described below based on the drawings from FIG. 2 onwards. First, in Fig. 2 showing a muddy water sealed type shield excavator, 1 is a shield frame, 2 is a cutter, 3 is a cutter chamber,
4 is a bulkhead of the cutter chamber, 5 is a cutter support frame, 6 is a shield jack, and 7 is a segment. Inside the cutter chamber 3, there are a mud water pipe ₈ having a mud water pump P1 and leading to the mud water tank _T1 , and a mud drain pipe ₉ having a mud water pump P2 and leading to the mud water tank _T2 . Each of them is connected. The above is a normal configuration of this type of shield excavator, and the cutter 2 is equipped with the means 10 for detecting the earth pressure of the face ground S. This earth pressure detection means 10 is a ground penetrating jack equipped with a telescopic rod 11a that is mounted across the center of the cutter 2 and the bulkhead 4, projects from the front of the cutter 2, and penetrates into the face ground S. 1
1 and a penetrator housed in the cylinder of the jack 11 in order to detect the penetration force of the telescopic rod 11a against the face ground S, that is, the earth pressure resistance that the telescopic rod 11a receives when penetrating, as the actual earth pressure of the face ground S. The main part is composed of an input detector 12 (see FIG. 3), and is provided with a jack penetration amount detector 13. Further, as shown in FIG. 2, the shield excavator is equipped with a pressure detector 14 for detecting mud water pressure in the cutter chamber 3, and an excavation speed detector 15 for detecting the propulsion speed of the shield jack 6. . Each of the detectors 12 to 15 is connected to a face control device shown in FIG. 3, and the related configuration will be described below. First, the output of the penetration amount detector 13 of the ground penetration jack 11 in the earth pressure detection means 10 is connected to the input of the jack penetration speed calculator 16, and the jack penetration speed calculator 16 and the soil quality setting device 17 are connected to each other. Each output section is connected to an input section of a face stable earth pressure calculator (hereinafter abbreviated as earth pressure calculator) 18. Here, the type of soil (for example, gravel, sand, shield, etc.) is set in the soil quality setting device 17, and a soil quality signal corresponding to the soil quality being excavated is output. This earth pressure calculator 18 is the jack penetration amount detector 1
3, and based on each output signal value from the jack penetration speed calculator 16 which calculates the jack penetration speed from the penetration amount outputted from now on, and the soil quality setting device 17, calculate the stable earth pressure at the face that stabilizes the face ground mountain S. The output side is connected to the manual face earth pressure setting device (hereinafter referred to as the manual earth pressure setting device) 1 via the changeover switch SW ₁ .
9 and the face earth pressure comparison calculator 20. Here, the earth pressure calculator 18 is set with a calculation formula for stability of face earth pressure by soil type obtained by experimentally correcting the face stability theory corresponding to the earth pressure at the face, and here the stable earth pressure at the face is calculated. calculate. Specifically, an empirical formula organized based on a large amount of data measured in the past for each type of soil is set in the earth pressure calculator 18. In the embodiment of the present invention, the earth pressure detection means 10 has a well-known Dutch cone shape as a standard, but in this case, the detection is generally performed based on the cone tip angle, cone bottom area, penetration speed, etc. The penetration force must be calculated by correcting the actual measured value to a Dutch cone shape. This calculation is based on a large amount of experimental data on the penetration force of the Dutch Dutch cone for each type of soil. and,
Using these data and determining the soil quality and penetration force, it is possible to check whether the face is stable. By the way, in the above earth pressure detection means,
Data other than the penetration speed, such as the cone tip angle, are determined at the time of manufacture and can be corrected in advance, but the penetration speed cannot be corrected in advance because it changes depending on the soil quality or shield digging speed. Here, a typical example of the above experimental formula that is set is when the soil type is a gravel layer (this soil type information is stored in the soil type setting device 17).
There is a formula: qc=4N (relationship between qc value and N value of Dutch cone). Here, qc is penetration force (referring to face earth pressure) [Kg/cm ² ], and N is a value measured by the standard penetration test method specified in JIS A 12191961. The N value is boring data during a geological survey, and is input into the earth pressure calculator 18 in advance. By the way, these are all data on vertical penetration to the ground surface, and when penetrating almost horizontally to the ground surface as in the present invention, the experimental results are affected by the earth's gravity, groundwater pressure, and penetration speed. Formula qc=
Not necessarily 4N. Therefore, it is necessary to input the penetration amount and penetration speed, that is, introduce the formula qc = 4N + α, and correct the above experimental formula qc = 4N using α. It was also found that when the ground penetration speed exceeds a certain limit, it has no effect on the correction of α. Here, the unit of α is [Kg/cm ² ] like the qc value. This α is a correction value obtained from a comparative experiment between horizontal penetration and vertical penetration under the same soil quality and under the same conditions. Therefore, qc=4N is corrected using this α to calculate the appropriate face stable earth pressure. In addition, the input section of the face earth pressure comparison calculator 20 includes:
The output part of the actually measured earth pressure correction calculator 29 connected to the jack penetrating force detector 12 is connected thereto. The output side of the face earth pressure comparison calculator 20 is a face pressure calculator 21 to which a groundwater level setting device 22 is connected.
And, shield jack 6 with stable earth pressure maintained at the face.
It is connected to each input side of a control speed calculator 25 that calculates a propulsion speed control value so that the vehicle is propelled. The output sides of the face pressure calculator 21 and the pressure detector 14 in the cutter chamber 3 described above are connected to the input part of the face pressure comparison calculator 23, and the output sides of each of the ratio operational amplifiers 24 and 32 are connected to the input part of the face pressure comparison calculator 23. It is connected to each input part of the variable motors M ₁ and M ₂ for driving the sending/discharging mud water pumps P ₁ and P ₂ through. On the other hand, the output side of the control speed calculator 25 is connected to the input part of the comparison calculator 27. Here, in the case of the control speed calculator 25, the jerk propulsion speed corresponding to the optimum earth pressure in front of the face is determined in advance, and based on the optimum earth pressure value in front of the face which is the output from the face earth pressure comparison calculator 20, The corresponding jack propulsion speed is calculated. That is, the control speed calculator 25 uses the cylindrical body of the shield propulsion machine as a penetration jack, and when comparing this with a standard Dutch Dutch cone, corrections are made based on the penetration shape, such as the cone tip angle, cone bottom area, and penetration speed. The calculated speed is set. Therefore, if the soil quality signal of the soil quality setting device 17 and the penetration speed of the earth pressure detection means 10 are arbitrarily determined, the setting of the jacking propulsion speed of the control speed calculator 25 can be performed using the soil quality signal of the soil quality setting device 17 and the soil pressure detection means 10. The correction speed corresponding to the penetration speed of 10 is also centrally determined. Therefore, the jack propulsion speed signal of the control speed calculator 25 is artificially set in advance using the data of the soil quality setting device 17 and the data of the earth pressure detecting means 10. On the other hand, the signals from the earth pressure calculator 18 and the measured earth pressure calculator 29 are input to the face earth pressure comparison calculator 20, which uses the signal from the earth pressure calculator 18 as a reference to calculate the actually measured corrected earth pressure. Vessel 29
The deviation (±△q) from the earth pressure calculator 18 is calculated, and a value of “signal value ±△q from the earth pressure calculator 18” is calculated. This calculated value is sent to the control speed calculator 25
If the set signal is input to , the set signal set here will be amplified and output. still,
In this case, of course, P, PI, or PID control is included. And this control speed calculator 2
The jack propulsion speed signal obtained in step 5 ultimately controls the propulsion drive pump _P3 , as will be described later. On the other hand, the input part of this comparison calculator 27 is also connected to the output side of the shield jack propulsion speed calculator 31, which allows the propulsion detector 15 of the shield jack 6 to calculate the shield jack propulsion from the shield jack propulsion amount. The output section of the comparator 27 is connected via a servo amplifier 28 to a variable pump _P3 for driving the shield jack propulsion. Further, the output parts of the penetration speed calculator 16 and the shield jack speed calculator 31 of the ground penetrating jack 11 are also connected to the input part of the speed ratio calculator 30. Here, the speed ratio calculator 30 calculates, for example, penetration speed+propulsion speed of the excavator/penetration speed. In other words, the actual earth pressure obtained by the penetration force detector 12 is small in addition to the penetration speed, but it is affected by the propulsion speed of the shield excavator, so for example, the ratio as a correction factor shown in the above formula is calculated. be. The output side of this speed ratio calculator 30 is connected to the actually measured earth pressure correction calculator 29 via a changeover switch _SW2 . Here, in the case of the actually measured earth pressure correction calculator 29,
As mentioned above, since the actual earth pressure obtained by the penetration force detector 12 is affected by the propulsion speed of the excavator (the propulsion speed is added to the penetration speed), it is necessary to remove the influence of the propulsion speed. Therefore, the computation unit 29 calculates the corrected earth pressure shown in the following formula. Corrected earth pressure = Actual earth pressure × Penetration speed + Propulsion speed / Penetration speed Note that the changeover switch SW ₁ on the earth pressure calculator 18 side and the changeover switch SW ₂ on the speed ratio calculator 30 side are configured to be interlocked, and the switching When the switch SW ₁ is in the connection position between the earth pressure calculator 18 and the face earth pressure comparison calculator 20, the other changeover switch SW ₂ is closed, and the changeover switch SW ₁ is in the connection position with the manual earth pressure setting device 19. When the switch is switched, the other switch SW ₂ is opened. Next, a method for controlling the face of a shield tunneling machine based on the above configuration will be described. First, jack for ground penetration 1
By extending and operating the cutter 1 with hydraulic pressure, the telescopic rod 11a is projected forward of the cutter 2 and penetrates into the face ground S. In this state, each of the feed/drainage pumps P ₁ and P ₂ is operated, the cutter 2 is rotationally driven, and the variable hydraulic pump P ₃ for driving the shield jack propulsion is started. Eventually, the muddy water in the muddy water tank _T1 is sent into the cutter chamber 3 from the muddy water pipe 8, and while filling this chamber, it is transferred to the muddy water tank through the muddy water pipe 9.
Shield excavation work begins with muddy water circulating inside _T2 . At this time, the changeover switch SW ₁ in FIG.
SW ₂ is closed. Then, at the same time as the start of the shield excavation work,
The output signal of the penetration amount detector 13 of the ground penetration jack 11 enters the penetration speed calculator 16, and this output signal and the soil quality setting device 18 are input. Therefore, this earth pressure calculator 18 calculates the penetration speed calculation value signal of the jack 11 calculated by the penetration speed calculator 16 based on the penetration amount detection value signal of the jack 11 by the penetration amount detector 13, From the soil quality signal of the face ground pile S preset in the soil quality setting device 17, a face stable earth pressure value at which the face ground pile S is stabilized is calculated, and the calculated value signal is compared with the face earth pressure via the switch _SW1 . It is transmitted to the arithmetic unit 20. The calculator 20 also contains the actual earth pressure of the face ground S detected by the penetration force detector 12 of the jack 11 for ground penetration, together with the stable earth pressure signal from the earth pressure calculator 18. A signal is also input, but if this actual earth pressure signal is directly input, the face stable earth pressure and the actual earth pressure will not be equal. Therefore, the jack penetration speed calculator 16 also transmits the calculated penetration speed signal of the jack 11 to the speed ratio calculator 30, and the jack penetration speed calculator 16 also transmits the calculated value signal of the jack 11 to the speed ratio calculator 30. Propulsion speed calculator 3 based on the actual propulsion amount of 6.
The calculated propulsion speed signal of the shield jack 11 calculated by No. 1 is also input. The speed ratio calculator 30 stores the initial speed of the ground penetration jack 11 when penetrating the ground, calculates the ratio between the penetration speed and the actual propulsion speed of the shield jack 6, and calculates the result. is transmitted to the actually measured earth pressure correction calculator 29. The actually measured earth pressure correction calculator 29 calculates the penetration speed of the ground penetration jack 11 and the shield jack 6.
The actual earth pressure detected by the penetration force detector 12 is corrected based on the ratio with the propulsion speed, and the corrected earth pressure signal is sent to the above-mentioned face earth pressure comparison calculator 20.
I am sending it to Therefore, the comparison calculator 20 is similar to the earth pressure calculator 1.
The stable earth pressure at the face calculated in step 8 is compared with the actually measured corrected earth pressure corrected by the actually measured earth pressure correction calculator 29, and the resulting optimal earth pressure signal in front of the face is sent to the face pressure calculator 21. send to That is, the face earth pressure comparison calculator 20 takes the stable earth pressure value of the face, which is the output of the earth pressure calculator 15, as positive, and uses the corrected earth pressure value, which is the output of the measured earth pressure correction calculator 29, as a feedback signal to calculate these values. Compare each value, and if there is a deviation as a result of the comparison, earth pressure calculator 1
The deviation is corrected to the signal from 8 to calculate the optimal earth pressure in front of the face, and this is output. Writing this concretely into a formula looks like this: Output of face earth pressure comparison calculator 20 = earth pressure calculator 18 + (earth pressure calculator 18 - actually measured earth pressure correction calculator 29) Here, the value of (earth pressure calculator 18 - actually measured earth pressure correction calculator 29) will vary by ±△q depending on the condition of the ground. Therefore, the face earth pressure comparison calculator 20
The output has the following three cases. Output of the earth pressure calculator 18 Output of the earth pressure calculator 18 +△q Output of the earth pressure calculator 18 -△q Here, the optimum earth pressure in front of the face is defined as the above deviation in the stable earth pressure value at the face. This refers to the value taken into consideration. The face pressure calculator 21 calculates the optimal earth pressure in front of the face,
Based on the groundwater pressure (face water pressure) set in advance by the groundwater level setting device 22, an appropriate mud water pressure to keep the rock face _S1 stable is calculated and set. The resulting mud water pressure setting signal is sent to the face pressure comparison calculator 2.
3 to the ratio operational amplifiers 24, 32,
These ratio operational amplifiers can be used to drive pump motors.
It is converted into a rotation speed control command signal for M ₁ and M ₂ , amplified, and input to each motor M ₁ and M ₂ . In this way, the motors M ₁ and M ₂ operate according to the rotational speed control command signal and drive the feed and mud water pumps P ₁ and P ₂ , so that the discharge pressure of these pumps is maintained at the same level as that in the cutter chamber 3. The muddy water pressure is controlled to be equivalent to the muddy water setting pressure determined by the face pressure calculator 21. In this case, whether or not the muddy water pressure in the cutter chamber 3 is actually equivalent to the muddy water setting pressure is determined by the pressure detector 14 detecting the muddy water pressure in the cutter chamber 3 and sending a signal to the face pressure comparison calculator 23. The calculator 23 compares and calculates the mud water pressure setting signal from the face pressure calculator 21 with the actual mud water pressure measurement signal in the cutter chamber 3 detected by the pressure detector 14 as described above. be done. If there is a deviation between the actual mud water pressure in the cutter chamber 3 and the mud water set pressure, a deviation signal is sent from the face pressure comparison calculator 23 to each of the ratio operational amplifiers 24 and 32 in order to correct the deviation. As a result, the rotational speed of each motor M ₁ and M ₂ is corrected and controlled by the deviation. Simultaneously with the automatic control of the rotational speed of the motors M ₁ and M ₂ as described above, the control speed calculator 25 of the shield jack control system maintains stable earth pressure at the face based on the signal from the earth pressure comparison calculator 20. The optimum propulsion control speed of the shield jack 6 is calculated, and the resulting signal is passed through the comparator 27 and the servo amplifier 28 as a control signal for the variable hydraulic pump P ₃ for driving the shield jack propulsion, respectively. ₃ to control this. At this time, the comparison calculation unit 27 compares the actual propulsion speed calculated by the propulsion speed calculation unit 31 based on the measured propulsion amount of the shield jack 6 detected by the propulsion amount detector 15 and the control speed calculation unit 25. A comparison calculation is made to determine whether or not the calculated control speed is equivalent. As a result, if there is a deviation between the actual propulsion speed and the control speed,
By correcting the signal from the control speed calculator 25, the comparison calculator 27 sends a deviation speed correction signal to the variable hydraulic pump _P3 via the servo amplifier 28 to automatically control the correction. Also,
The propulsion speed of the shield jack 6 is controlled so as to maintain the front earth pressure of the face mountain S in a stable state at all times. As described above, during shield excavation, the mud water pressure applied from inside the cutter chamber 3 to the face surface is transmitted so that it is equivalent to the mud water pressure setting command signal from the face pressure calculator 21, and the variable motor for driving the mud water pump is sent.
At the same time as M ₁ and M ₂ are controlled, the propulsion speed of the shield jack 6 is also controlled as described above, so that the face ground mountain S is moved in the cutter chamber 3 against the actual earth pressure and groundwater pressure. It is always maintained in a stable state by mud water pressure. In addition, in this embodiment, during shield excavation, the penetration amount of the jack 11 for ground penetration into the face ground mountain S, that is, the penetration distance, is constant and is variable in order to keep the actual earth pressure detected by the penetration force detector 12 constant. It is also possible to control motors M ₁ , M ₂ and variable hydraulic pump P ₃ . In this case, it is only necessary to switch the changeover switch SW ₁ to the manual earth pressure setting device 19 side, so that the signal from the earth pressure calculator 18 is not inputted as a feedback signal to the face earth pressure comparison calculator 20, and this calculation is performed. Vessel 2
0 is input with a face stabilizing earth pressure signal preset in the manual earth pressure setting device 19 as the earth pressure at which the face is stabilized depending on the soil quality. Therefore, the other changeover switch _SW2 , which is interlocked with the changeover switch _SW1 , is open and the signal from the speed ratio calculator 30 is cut off. Also, the manual earth pressure setting device 19
These are controlled by sending signals from the variable motors M ₁ and M ₂ and the variable hydraulic pump P ₃ . The above is a method for controlling the face stability of a shield excavation machine. When stabilizing the face when shield excavation is stopped, the earth pressure detection means 10 is penetrated into the face ground S and only the mud water pump P ₁ is operated. Only the pump discharge may be controlled using the control system shown in FIG. 3 in the same manner as in the case of shield excavation described above. That is, when shield excavation is stopped, while the earth pressure detection means 10 once penetrates the earth pressure ground S, only the pump _P1 is turned on so that the outputs of the earth pressure calculator 18 and the measured earth pressure correction calculator 29 are equal. With this, mud water pressure is applied to the cutter chamber 3. Then, when the pressures become equal, the pump _P1 is stopped and the pressure at this time is set in the face pressure calculator 21. In such a state, the face pressure calculator 21 controls the pump _P1 by starting and stopping so that the pressure is always at the set pressure. In this way, the face can be stabilized because the initial state can always be maintained. Since the mud water pressure in the cutter chamber 3 is controlled to oppose the earth pressure and groundwater pressure in front of the face, the face can be stabilized even when shield excavation is stopped. In this case, since the slurry water pump _P2 is stopped, an appropriate gate valve should be provided in the slurry water pipe 9 to prevent the muddy water in the cutter chamber 3 from leaking into the waste mud water tank _T2 . Of course. Note that the earth pressure detection means 10 in the above embodiment is not necessarily limited to a jack structure, but may be of any structure as long as it can penetrate into the face earth S, and therefore, the mounting position can be set arbitrarily. good. Furthermore, it is sufficient to set the actual earth pressure data in the manual earth pressure setting device 19, and the means for collecting the actual earth pressure data may have substantially the same configuration as the earth pressure detecting means 10, as shown in FIG. 4, for example. It is sufficient to read the values displayed on the penetration force indicator 10b and the penetration speed meter 10c by protruding another data jack 10a radially outward of the shield frame 1 and penetrating the undisturbed ground. The actual measured value data may be set in the manual earth pressure setting 19, and the face may be controlled as described in the above embodiment. That is, the penetration force indicator 10b and the penetration speed meter 1
The data appearing at 0c is recorded on a digital recorder via an A/D converter, and the data is recorded and set in the data area, ie, memory, of the manual earth pressure setting device 19. Data transfer is recorded as a digital code of 0 and 1 in the area of the manual earth pressure setting device 19 using pulses from a data recorder. [Effects of the Invention] In short, in this invention, the shield excavator itself can directly detect the actual earth pressure of the face ground using the earth pressure detection means that protrudes from the front face of its cutter and penetrates into the face ground. There is no need to perform soil sampling, and since the detected actual earth pressure is corrected by the ratio of the penetration speed of the earth pressure detection means and the shield jack propulsion speed, the corrected actual earth pressure and the face ground are stabilized. The optimum earth pressure for stabilizing the face ground can be accurately calculated from the calculated earth pressure, and the reliability of the calculated optimum earth pressure is not affected by the speed difference between the earth pressure detecting means and the shield jack. There will be no fear whatsoever. In addition, the optimal earth pressure value calculated as described above is converted into a shield jack propulsion speed control signal, and that signal is used to control the shield jack propulsion speed in accordance with the earth pressure of the face ground. As a result, the stable rock face will not be disturbed or collapsed due to the propulsion of the shield jack. In addition, at the same time as controlling the propulsion speed of the shield jack, the flow rate of mud water being fed and drained is controlled so that the mud water pressure in the cutter chamber always opposes the earth pressure and water pressure of the face ground, so according to the method of the present invention, The rock face can be reliably stabilized at all times. Furthermore, even if a collapse of the face earth occurs, the earth pressure detection means constantly detects the earth pressure of the face, so that the collapse of the face can be directly detected.
Therefore, countermeasures can be taken quickly and ground subsidence can be kept to a minimum. In addition, this invention does not require a group of instruments unlike conventional dry sand amount management, deviation flow rate management, etc., so equipment costs can be reduced. At the same time, the behavior of the face can be directly measured and controlled, so it is possible to directly measure and control the behavior of the face. The line can be used simply as a fluid transport system line for earth and sand (excavation waste), and therefore, the earth and sand control of this type of conventional mud water supply and drainage line can be made unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional configuration diagram of a conventional muddy shield tunneling machine, FIG. 2 is a schematic cross-sectional diagram of a muddy shield tunneling machine according to a preferred embodiment of the present invention, and FIG. 3 is a face stability control diagram of the same machine. The system diagram, Figure 4, shows the means for collecting actual earth pressure measurement data. In the figure, 2 is a cutter, 3 is a cutter chamber, 6 is a shield jack, and 10 is an earth pressure detection means.

Claims (1)

[Claims] 1. In the face control method of a shield excavator that stabilizes the face ground by sending muddy water into the cutter chamber, an earth pressure detection means is penetrated into the face ground from the front of the cutter to detect the actual earth pressure of the ground. A corrected earth pressure value is obtained by correcting the actual earth pressure by the ratio of the penetration speed of the earth pressure detection means and the shield jack propulsion speed, and this corrected earth pressure value, the penetration speed of the earth pressure detection means, and the excavation The stable earth pressure value at the face determined based on the soil quality or the stable earth pressure value at the face from a manual earth pressure setting device set with previously measured earth pressure data is compared to find the deviation between these values and this deviation. is added to the stable earth pressure value of the face to obtain the optimum earth pressure value in front of the face, and then this optimum earth pressure value in front of the face is applied to a control system in which the propulsion jacking speed determined by the relationship between the soil quality and the jacking penetration speed is set in advance. The shield jack propulsion speed signal is determined by inputting it to the speed calculator, and that signal is used to control the shield jack propulsion speed in accordance with the earth pressure of the face ground, and also to control the mud water pressure in the cutter chamber. A face control method for a shield excavator, which is characterized by controlling the flow rate of feeding and draining water so as to counter the earth pressure and water pressure of the face ground.