JPH05263584A - Shield tunneling machine - Google Patents

Abstract

PURPOSE:To grasp definitely the properties of earth and sand filled up and pressurized in a cutter chamber during shielding operation, carry out proper shield control and build transverse pits swiftly during earth pressure shield excavation in any natural ground. CONSTITUTION:A bulkhead 12 is installed to the front of a shield cylinder where a cutter chamber 6 is installed by way of this bulkhead. To the front of the cutter chamber is installed a drill 3. An earth discharge device 8 is connected to the rear side of the cutter chamber. In a shield machine designed as described above, a density/humidity measuring instrument 21a which measures the density and or the moisture content, is installed to the bulkhead and or an excavator or the like by using a radio isotope(RI) and directly measures the density and or the humidity content of the earth and sand in the cutter chamber. This detected value helps an operator to estimate and grasp the properties of the earth and sand so that stabilized excavation may be carried out by controlling the above measurement.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield machine used when constructing a tunnel in the ground, more specifically, excavated earth and sand taken into a face chamber by using a radioisotope. The present invention relates to a shield machine that measures the density and water content of a slab and controls excavation. In a conventional earth pressure type shield, earth pressure management, additive injection management, earth removal management and the like are mutually effective as excavation control methods for maintaining stable face and maintaining stable excavation. It is related and done. In other words, there is earth pressure management as a direct method of stabilizing the face, excavating sediment,
Alternatively, a mixture of excavated soil and additives is filled in the face of the face and the screw conveyor, and the thrust of the shield jack generates pressure in the face of the face to counteract the earth pressure and groundwater pressure of the ground that acts on the face. To control the face. In this case, the pressure in the face chamber is constantly measured by an earth pressure gauge provided in the face chamber, and the detected pressure value is within a range of a lower limit value in which ground collapse does not occur and an upper limit value in which ground uplift does not occur. The excavation control is performed by adjusting the propulsion speed of the shield jack and the rotation of the screw conveyor so as to maintain a static earth pressure that does not cause the ground deformation. At this time, it is a necessary condition that the excavated earth and sand filled and pressurized in the face chamber and the screw conveyor have appropriate plastic fluidity and lower water permeability. As this excavation control, conventionally, the control width of the resistance torque value of the rotary cutter provided in the shield machine is set, and in order to keep it at a constant value, additives are appropriately injected into the excavated earth and sand and they are mechanically kneaded. Soil properties are converted to the above soil properties. The conversion effect is confirmed by observing the soil removal properties such as the measurement of the rotary cutter torque value, the soil slump value, and the water content ratio, and the excavation management is performed while the results are fielded back to the excavation. However, it is possible to check the soil resistance conversion effect by kneading the excavated earth and sand or the mixture of the excavated earth and additive with the additive in the face face chamber by the kneading resistance torque value. However, the detected rotary cutter torque value is the sum of the cutting resistance torque and the kneading resistance torque.Because the cutting resistance torque changes depending on the excavation soil quality, excavation speed, etc., an accurate kneading resistance torque value can be detected. However, it was not enough to confirm the kneading effect. As described above, the method of confirming the kneading effect by the rotary cutter resistance torque is indirect, and it is difficult to constantly and accurately grasp the properties of the kneaded earth and sand. Superfluidity, etc. could not be sensed until the soil was actually discharged, and there was a risk of blockage in the soil discharge device or eruption of sediment from the soil discharge port. In addition, it is more difficult to uniformly manage the excavated kneaded soil in the case of complicated alternating excavation where the stratum of the excavated ground changes drastically, and there is a problem that spouting from the soil discharge device is likely to occur especially under high water pressure. It was The present invention has been proposed in view of the above, and an object of the present invention is to excavate earth pressure type shields by excavating earth and sand filled with pressure in a face chamber during excavation in any ground. The purpose of the present invention is to provide a shield machine that enables accurate grasping of properties and appropriate excavation management, and that can quickly build a lateral pit. In order to achieve the above-mentioned object, the present invention is, in short, provided with a partition wall in the front part of the shield cylinder, and a face chamber is provided through the partition wall, and a face chamber is provided in front of the face chamber. In a shield machine in which a drilling tool is installed in the ground and a soil discharging device is connected to the rear of the face chamber, the density and / or the water content is measured using a radioisotope (RI) for the partition wall and / or the drilling tool.・ A moisture meter is installed to directly measure the density and / or water content of the sediment in the face chamber, and the detected value is used to estimate and grasp the property of the sediment, and to manage this to perform stable excavation. It is a summary. In the cutting chamber and the soil discharging device, the excavated earth or the earth mixed with the additive and the excavated earth is converted into so-called "mud" having proper plastic fluidity and impermeable property. And is filled under pressure. In general, the fluidity of earth and sand depends on its water content, and the higher the water content, the easier it is for it to flow. Therefore, in order to maintain the property of the excavated earth and sand filled in the face chamber and the earth removing device uniformly and to maintain a stable excavation, the present invention has the density of the excavated earth and sand in the face chamber as described above. / Or measure the water content and manage the excavation of the shield machine so as to keep this measured value constant. For example, when it is eruptive superfluid sand, it is possible to know it in the face chamber. Is possible,
Since there is a sufficient time before soil removal, it is possible to take measures such as promptly reducing the amount of additive injection before the accident occurs. Embodiment 1 FIGS. 1A and 1B are a front view and a vertical sectional view of an earth pressure type shield machine 1 showing a first embodiment of the present invention.
Thus, the shield machine 1 in this embodiment excavates the face 4 of the excavation portion with the excavator 3 which can rotate in the forward and reverse directions on the front surface of the shield outer cylinder 2 having a substantially cylindrical shape, and shields the excavated earth and sand 5. The face 4 was filled in the front of the outer cylinder 2, and the face 4 was held mainly by the mixture of the excavated sand 5 and the additive injected from the inside by the well-known means. The earth excavation 7 is excavated while being discharged to the outside through an earth discharging device 8 such as a screw conveyor or a belt conveyor. The structure of the excavator 3 is a general structure including a cutter spoke, an excavation bit, a copy cutter, a fish tail, etc.
Further, for example, stirring tools 18a and 18b are provided behind the excavation tool 3. In addition, it goes without saying that the agitator can be provided so as to project on the outer circumference of the rotary shaft 11. In the figure, 9 is a radial cutter spoke which constitutes the excavator 3, and 10 is an excavation bit attached to the front part of the cutter spoke 9 of the excavator 3, which is connected to the substantially central portion of the cutter spoke 9. The tip of the rotary shaft 11 is connected, and the rotary shaft 11 is axially supported by a bearing provided in the partition wall 12. Further, an excavation tool drive motor 13 provided behind the partition wall 12 is connected to the rotary shaft 11 via a gear mechanism, whereby the excavation tool 3 is driven, and the screw conveyor 8 is a screw conveyor that drives the excavation tool 3. The motor 14 is attached. The segment 15 is constructed in a substantially cylindrical shape as the excavation proceeds, and a gap such as the backfill material 16 is filled in the gap between the ground G and the segment 15. However, in this embodiment, in order to directly measure the soil quality of the excavated soil taken in the face chamber 6 and the mixture with the additive, the density of the sand is placed at a good position of the partition wall 12. Density / moisture meter 21 for measuring water content
a is provided to the front, that is, facing the face of the face 6 and the cutter / spoke 9 that is a component of the excavator 3 is provided with a density / water content measuring device 21b rearward, that is, to the face of the face 6 ing. It should be noted that the density / moisture measuring device 21b provided on the cutter spoke 9 is located on the outer peripheral side, and the excavator 3 rotates once so that the soil quality of the entire excavated soil in the face chamber 6 can be measured. It has become. Also,
A cable 22 is connected to the density / water content measurement 21a, 21b for taking out the obtained data signal to the outside and processing the data by a device including a subsequent electronic circuit. FIG. 2A shows a partition wall in the embodiment of the present invention.
The detection capsule 23 of the density / moisture measuring instrument 21a provided in 12 is extended and detected in a longitudinal section, and FIG. 2B shows the detection capsule 23 housed in a shielding box 24. That is, the density
The front part of the shielding box 24 having a hollow inside which constitutes the moisture measuring device 21a is attached to the opening of the partition wall 12, and the detection capsule 23 can be freely retracted from the front side of the shielding box 24 to the face chamber 6 side. ing. Reference numeral 26 in the drawing denotes a jack provided in the shielding box 24 and connected to the detection capsule 23, and the detection capsule 23 can be freely expanded and contracted through this jack 26, and at the time of detection, as shown in (a), It is in a state of extending and projecting to the side of the face chamber 6 and can be fixed at that position. In this case, a fixed stirrer 18c having a bottomed cylindrical shape and protruding toward the front side of the face chamber 6 is provided at the front part of the partition wall 12.
The detection capsule 23 projects into the hollow portion of c and is configured so as to prevent the detection capsule 23 from being damaged by the earth and sand in the face chamber 6 and causing an accident. When not detected, the detection capsule 23 can be housed in the shielding box 24 by retracting the jack 26 as shown in (b).
In this way, the detection capsule 23 can be freely moved in and out of the shielding box 24. The density / moisture detector 21a provided with the detection capsule 23 uses a radioisotope RI (radioisotope) which is a well-known technique. A radiation source 25 is provided inside the detection capsule 23 and a shielding box is provided. A detector 29 for measuring the radiation dose from the radiation source 25, a standard body 28, and the like are provided in front of the inside of 24. Further, the detector 29 is connected to the arithmetic unit 30 and the display 31 via cables 22 and 32. Source 25
For this, a radioactive substance that emits radiation, for example, cobalt 60 (Co · 60) for density measurement, californium 252 (cf-252) for water content measurement, etc., is used in a stainless steel cylindrical container. In operation, as shown in FIGS. 2 (a) and 2 (c), the radiation R radiated from the radiation source 25 passes through the detection capsule 23 and the earth and sand 5 in the face chamber 6 to the detector. It is possible to measure the density and the amount of water in the earth and sand 5 in the face chamber 6 by irradiating 29 and measuring the amount of radiation transmitted at this time. Detector
The radiation dose detected at 29 is converted into an electric signal and input to the arithmetic unit 30 via the cable 22, and after being calculated, the display signal is input to the display unit 31 via the cable 32,
Density and / or water content is displayed. The moisture content W is W = ρw / (ρt −ρw) ×, where ρt (g / cm ³ ) is the wet density of the soil and ρw (g / cm ³ ) is the water content.
Calculated as 100 (%). In this way, the density and moisture detector 21a can always measure the density and / or the water content of the earth and sand 5 filled in the face chamber 6, whereby the excavated earth and sand 5 can be measured. It is possible to confirm the "mud" conversion effect and kneading effect. For example, if there are large variations in the detected values of the density / water content detectors 21a provided on the partition wall 12, it is determined that the kneading is insufficient, and the sand with a low density or a high water content has excessive fluidity, There is a possibility of eruption from the soil discharge port 17 of the conveyor 8. in this case,
By temporarily stopping the excavation and soil removal and performing sufficient kneading,
It is possible to make the properties of the earth and sand in the face chamber 6 uniform and prevent the eruption from the earth discharge port 17 in advance. In addition, the density ρc and the water content Wc of the earth and sand 5 in the face chamber 6 during stable excavation
Is within a certain range between the limit value that causes excessive rotation cutter torque or blockage in the soil discharging device and the limit value that causes ejection from the soil discharge port 17, and keep the detection value constant within this range. By performing the excavation management so as to keep the soil 5 at all times, the soil 5 becomes a mud having a uniform property and stable excavation can be performed. The radioactive isotope has a property that the radiation dose attenuates with the passage of time. Cobalt 60 above
(Co-60) and Californium 252 (Cf-252) have a relatively short half-life, and in order to ensure the accuracy of the measured value, the attenuation degree of the radiation source 25 is measured for a certain period, for example, once a week. Needs to be calibrated. Next, the calibration method shown in FIG. 2B will be described. The radiation source 25 in the detection capsule 23 is housed in a shield box 24 by a jack 26, the radiation R is applied to a standard body 28, passes through the standard body 28, and enters a detector 29. The value detected there was compared with the value obtained by measuring the amount of radiation passing through the standard body 28 in advance, and the
After confirming the radiation attenuation of 25, the arithmetic unit 30 is corrected. The standard body 28 is formed of a substance which is physically and chemically stable and hardly deteriorates over time, such as acrylic or glass. Moreover, if the total dose of the radiation source 25 is a low level of 100 microcuries or less, it is not subject to legal regulation and no special handling qualification is required. Figure 2 (c) shows the density of the cutter spoke 9
FIG. 6 is a vertical cross-sectional view of a state in which the moisture measuring instrument 21b detects, and this density / moisture measuring instrument 21b is also configured in the same manner as described above, and is detected in the hollow portion of the fixed stirring tool 18C projecting behind the cutter spoke 9. The capsule 23 is freely retractable via the jack 26, and the density and water content of the earth and sand 5 in the face chamber 6 can be measured. In the above embodiment, the density / moisture measuring device is used.
Although the case where 21a and 21b are respectively provided on the partition wall 12 side and the excavation tool 3 side has been shown, it is also possible to set the hollow shaft at another place, for example, the rotary shaft 11, and set it in that portion. Alternatively, the configuration may be provided in only one place. In addition, the measurement is not limited to both the density and the water content of the earth and sand 5, and either one can be measured and the excavation management can be performed based on that. FIG. 3 shows an example of the excavation flow chart of the present invention. In the figure, symbol S / J is a shield jack, S / C is a screw conveyor, Wc is a water content ratio of soil in the face chamber, and Wmin is The lower limit value of Wc, Wmax is the upper limit value of Wc, and We is the water content ratio of the earth and sand in the face chamber during the actual excavation. In the present invention, it is possible to confirm by the water content ratio that the property of the earth and sand in the face chamber 6 is detected, and the content of the additive is appropriately adjusted so as to be in a certain range (control width) in which the water content ratio is in a stable excavation state. By performing injection management, the earth and sand 5
The mud has a uniform property at all times, and stable excavation management can be performed without excessive cutter torque, blockage in the soil discharging device, or ejection from the soil discharging port 17. During the control of the water content ratio, the setting as shown by the following inequalities and the setting with a margin within the value predicting the occlusion or jetting allow more stable excavation control. Although the above-mentioned excavation management flow is an example in which it is managed by the water content ratio, the same effect can be obtained by managing it by the density, and both may be managed as a reference. As described above, if the properties of the earth and sand in the face chamber 6 are measured and managed, even if an obstruction or eruption is predicted during the excavation, the earth and sand will be in the form of the face chamber 6.
Since it does not reach the inside of the soil unloading device and these phenomena can be detected earlier, early preventive measures can be taken. As described above, according to the present invention, the density and / or water content of earth and sand in the face chamber of a shield machine that holds a face by excavated soil or a mixture of excavated soil and additives. Since a density / water content measuring device was installed to measure the density and / or water content of the excavated earth and sand in the face chamber, the detected values clearly identify the properties of the mud in the face chamber and the earth removing device. Even at large depths where complicated alternation and soil investigation are difficult, by uniformly controlling the density and / or water content of the soil in the face chamber, the excavation management becomes easier and the characteristics of the mud can be determined by the detected values in the face chamber. Since it is observed, it is possible to detect signs such as eruptions and blockages earlier, and respond accordingly, so that troubles can be prevented in advance and smooth excavation can be performed. , Is effective. [0024]

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] (a) and (b) are respectively a front view and a vertical sectional view of a shield machine showing a first embodiment of the present invention. 2 (a), (b) and (c) are cross-sectional views of a density / water content measuring device. FIG. 3 shows an example of an excavation management flow chart of the present invention. [Explanation of symbols] 1 shield machine 2 shield outer cylinder 3 excavation tool 4 cutting face 5 excavation earth and sand 6 cutting face chamber 7 excavation 8 excavation device 9 cutter spoke 10 excavation bit 11 rotating shaft 12 partition wall 13 excavation tool drive motor 14 screw conveyor motor 15 Segment 16 Backing material 17 Soil outlet 18a Stirrer 18c Fixed stirrer 21a Density / moisture analyzer 22 Cable 12 Detection capsule 24 Shielding box 25 Source 26 Jack 28 Standard body 29 Detector 30 Computing device 31 Display 32 Cable

Claims (1)

Claim: What is claimed is: 1. A shield is provided with a partition wall at the front portion thereof, a face chamber is provided through the partition wall, an excavation tool is provided in front of the face chamber, and a cutting tool is provided behind the face chamber. In a shield machine to which an earth discharging device is connected, a density / moisture measuring device for measuring the density and / or water content of the soil in the face chamber is provided on the partition wall and / or excavator. 2. The density / water content measuring device is a measuring device using a radioisotope (RI), which measures the density and / or water content of the earth and sand in the face chamber and keeps the measured values constant to eliminate the waste. The shield machine according to claim 1, further comprising a system for uniformly controlling soil properties and controlling excavation.