JPH0715897U - Ground detection device for shield machine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a rock mass detection device capable of three-dimensionally detecting the condition of rock mass. [Structure] The shield body 1 which is dug into the ground is provided with a boring pipe 5 projecting freely into and out of the ground 18 in front of the ground. Since the probe electrode 6 for detecting is provided, the state of the ground 18 in front of the shield body 1 can be detected over a wide range, so that efficient excavation is possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a front detector for a shield machine, which detects the state of the ground by measuring the resistivity of the ground.

[0002]

[Prior art]

 Conventionally, devices of this type are known, for example, those disclosed in Japanese Patent Publication No. 3-34559 and Japanese Patent Application Laid-Open No. 3-257395. In the former detection device, the energization electrode provided on the skin plate energizes the natural ground to form a potential distribution, and the apparent specific resistance is obtained from this potential distribution and the energized current, and the change in the apparent resistivity is determined. The state of the ground is detected from.

In the latter detection device, an arbitrary pair of electrodes is selected from a plurality of electrodes arranged in a matrix, a power source is connected, and the specific resistance in the ground is obtained based on the output signals of these electrodes. The ground condition is detected based on the obtained change in resistivity.

[0004]

[Problems to be solved by the device]

 However, with the above-mentioned conventional detection device, the detection range was limited to the vicinity of the skin plate and the cutter head, and it could not be used to detect underground obstacles in front of the shield machine. Moreover, since it is detected in two dimensions, it has problems such as difficulty in wide-range detection. The present invention has been made in order to improve such a problem. By detecting the ground three-dimensionally, it is possible to detect the state of the ground over a wide area. It is intended to provide.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a shield body for excavating in the ground with a boring pipe projecting freely into and out of the front ground, and the outer peripheral surface of the boring pipe. In addition, an exploration electrode for three-dimensionally detecting the resistivity distribution of the natural ground is provided.

[0006]

[Action]

 With the above configuration, since the ground condition in front of the shield body can be detected over a wide range, it is possible to efficiently excavate according to the ground condition.

[0007]

【Example】

 An embodiment of the present invention will be described in detail with reference to the drawings. Figure 1 shows a shield machine excavating in the ground. In this figure, 1 is a shield body, 2 is a cutter head rotatably provided in front of the shield body 1, and 3 is an excavated tunnel. The segment for lining the inner wall of the, and 4 shows the ground detection device of this invention. The ground detection device 4 has a boring tube 5 penetrating the cutter head 2 from the shield body 1 and protruding and retracting forward, and an exploration electrode 6 is provided in the middle of the boring tube 5.

As shown in FIGS. 2 and 3, the probe electrode 6 is formed by providing a plurality of electrodes 6b on the outer peripheral surface of a cylindrical insulator 6a at intervals in the axial direction. Is connected to a measuring device 8 shown in FIG. 4 installed in the shield body 1 or the like via a cable 7 wired in the insulator 6. The measuring device 8 has a relay circuit 9 to which the electrode 6b is connected, a relay control circuit 10 for controlling the relay circuit 9, a preamplifier 11 for amplifying a signal from the electrode 6b, a lock-in amplifier 12 for measuring a voltage, From a lock-in amplifier 13 that measures a current, a CPU and a display unit 14 that control the relay control circuit 10 and the lock-in amplifiers 12 and 13, and a constant current source 15 that supplies a constant current to the preamplifier 11 and the lock-in amplifier 13 It is configured.

The operation will be described next. During excavation by the shield machine, the boring pipe 5 is stored in the shield body 1 and pushed forward to a target position when the state of the ground 18 is detected. Then, the specific resistance of the natural ground 18 is measured by the measuring device 8 by the exploration electrode 6 provided in the middle of the boring pipe 5.

Now, for example, when each electrode 6b of the exploration electrode 6 is arranged in a dipole / dipole arrangement as shown in FIG. 5, a current is applied to C ₁ and C ₂ of the electrode 6b, and at that time, the ground 18 is The voltage generated by the flowing current is measured at the other electrodes P ₁ and P ₂ . At this time, the sensitivity of the exploration electrode 6 is within a circle of radius a centered on the QD in the natural ground 18 at a distance (n + 1) a / 2 from the electrode 6b, where a is the distance between the electrodes 6b. , The apparent resistivity value of this region is Pe = πan (n + 1) (n + 2) V / i where V: voltage of P ₁ and P ₂ i: current of C ₁ and C ₂ , and the apparent resistivity of By measuring the change, the state of the ground 18 can be detected.

Similarly, the electrodes C ₁ and C ₂ through which the current flows and the electrodes P ₁ and P ₂ for measuring the voltage are sequentially switched by the relay control circuit 10 that controls the relay circuit 9, and the other positions of the ground 18 are changed. Detect the state of. As a result, the resistivity distribution (pseudo-resistivity cross section) of the ground 18 can be obtained two-dimensionally, and the same measurement as above can be performed while rotating the boring pipe 5 to obtain the results shown in FIGS. It is possible to detect the state of the natural ground 18 in the area 19 indicated by the diagonal lines.

An area 20 in FIGS. 1 and 6 shows a range detected last time. Further, in the above-described embodiment, the case where the electrodes 6b are arranged in one row on the outer peripheral surface of the insulator 6a has been described, but as shown in FIGS. 8 and 9, a plurality of rows are arranged on the outer peripheral surface of the insulator 6a. If arranged, three-dimensional detection is possible without rotating the boring tube 5.

Further, although the electrodes 6b are arranged in the dipole / dipole arrangement in the above-mentioned embodiment, they may be arranged in the manner of a trench or a Schramberger, and the specific resistance distribution output to the measuring device may be a numerical value. Color display or contour line display may be used.

[0014]

[Effect of device]

 As described in detail above, this device projects the boring tube in front of the shield body and measures the resistivity distribution of the ground three-dimensionally by the exploration electrodes provided on this boring tube. Since it is possible to detect the ground condition, the condition of the ground during excavation can be accurately measured over a wide range.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a ground detection device of a shield machine according to an embodiment of the present invention.

FIG. 2 is a side view showing an exploration electrode of a rock mass detection apparatus according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 4 is a block diagram showing a measuring device of a rock mass detecting device according to an embodiment of the present invention.

FIG. 5 is an operation explanatory view of a rock mass detection apparatus according to an embodiment of the present invention.

FIG. 6 is an operation explanatory view of a rock mass detection device according to an embodiment of the present invention.

7 is a cross-sectional view taken along the line YY of FIG.

FIG. 8 is a side view of a probe electrode according to another embodiment of the present invention.

9 is a cross-sectional view taken along the line ZZ of FIG.

[Explanation of symbols]

 1 Shield body 5 Boring tube 6 Exploration electrode 18 Ground

Claims (1)

[Scope of utility model registration request] 1. A shield main body 1 for excavating in the ground is provided with a boring pipe 5 projecting freely into and out of the ground in front of the earth. A ground detection device for a shield machine, which is provided with an exploration electrode 6 for detecting selectively.