JPH10205267A - Ground excavating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability by obtaining a mean bit load, in which the return speed of bit load is maximized, from a measured bit load and feeding back the mean bit load to excavation trust. SOLUTION: One tip of a suspension wire 3 for an excavator 1 is wound on a reel 4, and the other tip is connected to a plunger 6 for a hydraulic cylinder 5. The suspension wire 3 is delivered at the time of the execution of works, and the excavator 1 is penetrated into a ground, and the ground is excavated. Bit load L in the excavation direction working an a bit part 1a is varied in a wave shape in a short period. A mean bit load, in which the return speed of load L is maximized, is used as optimum bit load at that time, and the actual bit load of the excavator 1 is controlled so as to reach optimum bit load. The cylinder 5 is hydraulically controlled and plunger load is changed, the tension T of the wire 3 is altered and bit load is controlled. Accordingly, optimum excavation conditions corresponding to geology can be set at a real time, and excavation can be controlled easily because excavation depends upon a single factor, and the burden of an operator can be lightened largely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of excavating a ground in which the excavation which has been conventionally performed by relying on the intuition of an operator is performed based on specific drilling data which can be easily obtained, thereby improving the excavation efficiency. About.

[0002]

2. Description of the Related Art Conventionally, in trench excavation in the underground diaphragm wall method, tunnel shaft, large diameter excavation in foundation pile construction of a large bridge, etc., an operator visually observes changes in indicators such as bit load, rotational torque and the like. While observing, he operated based on his intuition based on his experience.

On the other hand, due to recent advances in measurement technology and computer hardware, drilling data such as drilling torque, bit rotation speed, and bit thrust are measured during test excavation, and analysis is performed based on these drilling data. There is a technique that accurately grasps ground properties by using the information of the ground properties, and determines an optimum rotation torque, a bit load, and the like for each stratum based on the information on the ground properties to realize efficient excavation.

[0004]

However, the former method of excavating by relying on the operator's intuition has problems that the excavation efficiency is greatly influenced by the experience of the operator and that the operator is burdened with fatigue. In addition, when the hanging load of the excavator is insufficient due to an operation error, there is a problem that the excavator is tilted and the excavation accuracy is reduced.

[0005] On the other hand, in the case of a method in which ground properties are grasped by the latter preliminary survey and excavation conditions are set based on these data, it is necessary to attach various sensors to the excavator itself, and the excavator is remodeled. In addition, there is a problem that it takes a lot of trouble and time, and there is a problem that analysis and operation become complicated due to control of many excavation parameters. Furthermore, since the sampling number of test excavation cannot usually be large, the actual geology often differs from the survey result, and in reality, excavation is often not performed under optimal excavation conditions. Furthermore, even if the optimum bit load is determined from the sampling data, for example, since the actual operation depends on the operator's operation, the own weight of the excavator is excessively deposited on the excavation surface due to an operation error as in the former case. In some cases, the load of the excavator may be insufficient, and the excavator may be tilted to reduce excavation accuracy.

Accordingly, a main object of the present invention is to determine the optimum excavation conditions in real time based on easily obtained drilling information during excavation by an excavator, thereby reducing the burden on the operator and the ground properties at that time. It is an object of the present invention to provide a ground excavation method which realizes efficient excavation in accordance with the conditions.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention measures a bit load acting in the direction of excavation during excavation of ground by an excavator, and based on the bit load measurement, measures a bit load. An average bit load that maximizes the return speed of the drill bit is determined as an optimum bit load, and the drilling thrust is feedback-controlled so that the actual bit load becomes the optimum bit load.

In the present invention, the average bit load that maximizes the return speed of the bit load is determined as the optimum bit load based on the actually measured bit load, and this is fed back to the excavation thrust. The bit load is a digging thrust acting on the digging surface in the digging direction, but since the digging conditions are set based only on this single factor, real-time control is possible, and every digging time It is possible to set the best excavation conditions.

The "optimum bit weight" is a bit weight L
Is a numerical value defined as an average bit load L _O that maximizes the return speed −dL / dt of the above. More specifically, the return speed -dL / dt of the bit load L is a numerical value defined as a gradient θ when the bit load L decreases in a waveform diagram of the bit load, as shown in FIG. , Given in response to an arbitrary average bit weight _Lmi . Therefore, the average bit load L _O that maximizes the return speed of the bit load is represented graphically as shown in FIG.
The horizontal axis as the average bit weight L _mi, the average bit weight corresponding to the maximum value of the return rate -dL / dt bit load when plotted as a return rate -dL / dt bit load on the vertical axis. The actual bit load can be measured indirectly by measuring the hydraulic pressure of a hydraulic operating source that generally gives excavation thrust, but a bit thrust sensor provided in an excavation unit of an excavator may be used. It is also possible to measure directly.

Next, a first ground excavation method embodying the above method is to support one end of a wire rope suspending an excavator with a plunger of a cylinder and to provide a hydraulic oil path to be supplied to the cylinder. Install an oil pressure gauge inside to measure the actual bit load, determine the average bit load that maximizes the return speed of the bit load based on this actually measured bit load as the optimal bit load, the actual bit load is the optimal bit load and Thus, the hydraulic pressure of the cylinder is feedback-controlled.

In a second ground excavation method, a hydraulic indicator is provided in a hydraulic oil path of a hydraulic drive source for applying excavation thrust, and movement of an indicator needle of the hydraulic indicator is monitored by a camera. The return speed of the bit load is determined from the moving speed of the hydraulic pointer by image processing of a video, and the average bit load that maximizes the return speed of the bit load is determined as the optimum bit load. The feedback control of the hydraulic pressure of the hydraulic operation source is performed so that

[0012] The two ground excavation methods are considered as specific methods for automating the ground excavation method according to claim 1. According to these ground excavation methods,
An operation which conventionally relied on an operator operation can be easily automated under the above-mentioned optimum bit load control.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram of the case where the present invention is applied to trench excavation in the underground diaphragm wall method. The excavator 1 includes a suspension wire 3 of a crawler crane 2.
The excavator 1 is penetrated into the ground by the unwinding of the hanging wire 3, and a trench for constructing an underground continuous wall is excavated. The number of windings of the suspension wire 3 around the excavator 1 is four, and one end of the suspension wire 3 is wound on a reel 4 provided in the crawler crane 2, and the other end is on the crawler crane 2. It is connected to the plunger 6 of the installed hydraulic cylinder 5.

Therefore, the underwater weight of the excavator 1 is W (t
f) Assuming that the wire tension acting on the hanging wire 3 is T (tf), the bit load L (tf) in the excavation direction acting on the bit portion 1a of the excavator 1 is given by the following equation (1). Is represented by L (tf) = W−4T (1) During the excavation of the ground, the bit load L (tf) is changed into a wave shape in a relatively short period, for example, as shown in FIG. At this time, the return speed of the bit load-dL / dt (the ratio of the change amount dL of the bit load to the minute time dt when the bit load decreases) is defined by the following equation (2). −dL / dt = tan θ (2) That is, the return speed of the bit load −dL / dt is as shown in FIG.
Is a numerical value defined as a gradient θ when the bit weight L decreases, and is given in correspondence with an arbitrary average bit weight _Lmi .

In the present invention, by paying attention to the return speed -dL / dt of the bit weight, as shown in FIG. 4, the average bit weight L _mi to maximize the return speed -dL / dt of the bit weight particularly by defining the optimal bit loading L _O, actual bit weight in excavator 1 performs pressure feedback control so that the optimal bit loading L _O. Specifically, the plunger load in the hydraulic cylinder 5 is equal to the tension T of the suspension wire 3, and the tension T of the suspension wire 3 can be changed by changing the plunger load. The bit load is controlled by the hydraulic control of.

The structure of the hydraulic cylinder 5 supporting the other end of the hanging wire 3 and the hydraulic oil supply system thereof is as follows.
As shown in FIG. 2, the hydraulic cylinder 5 is arranged in a vertical direction, the other end of the suspension wire 3 is fixed to the tip of the plunger 6, and the operation between the hydraulic cylinder 5 and the hydraulic oil storage tank 13 is performed. Oil pressure sensor 11 in the middle of the oil path
, A relief valve 12 is provided, and a hydraulic oil supply passage 14 is formed across the relief valve 12 from the hydraulic oil storage tank 13, and a pump is provided in the middle of the hydraulic oil supply passage 14. The hydraulic pressure data measured by the hydraulic pressure sensor 11 is input to a computer 17 where it is analyzed. Then, in the computer 17, the return speed of the bit load-dL
When the average bit load that maximizes / dt, that is, the optimum bit load L _O is calculated, a command is issued to the relief valve 12 so that the actual bit load of the excavator 1 becomes the optimum bit load L _O. And the valve opening is adjusted. At the same time, a limit value may be set for the actually measured bit load, and if a bit load exceeding this limit value is detected, it may be set so as to take precedence over all controls to avoid an abnormality.

Next, a second example of a device for detecting the return speed of the bit load, as shown in FIG. 5, comprises a maximum value indicating needle 20 indicating the maximum value of the hanging load and a movable needle 21. It comprises a needle oil pressure indicator 19, a camera 22 for monitoring the oil pressure indicator 19, and a computer 23 for image-processing images captured by the camera 22.

Maximum value indicating needle 2 of the two-hand hydraulic indicator 19
Numeral 0 is a subordinate movement caused by the movement of the movable needle 21 and instructs the maximum value to be fixed. Actually, it designates the hydraulic pressure when the excavator 1 is suspended in the excavation groove. Thereafter, when the excavator 1 is brought into contact with the excavation surface, a decrease in the hydraulic pressure corresponding to the bit load occurs, and the movable needle 21 instructs the actual hydraulic value to move. Therefore, the amount corresponding to the opening angle ψ between the maximum value indicating needle 20 and the movable needle 21 is the bit load, and the return speed -dL / dt of the bit load is proportional to the clockwise speed of the movable needle 21. Therefore, the moving state of the movable needle 21 is monitored by the camera 22, and the image captured by the computer 23 is subjected to image processing to determine the return speed of the bit load, and the return speed of the bit load −dL. The average bit load that maximizes / dt is determined as the optimum bit load L _O , and is fed back to the hydraulic pressure of the hydraulic operating source that gives the excavation thrust.
Note that the hydraulic control can be performed by adjusting the tension of the hanging wire 3, that is, adjusting the opening of the relief valve 12, as in the case of the first example.

As another method, a return speed is obtained from a complicated waveform of a change in bit load by fuzzy control in which data of an empirical rule of a skilled operator with respect to the bit load and its fluctuation are obtained. Can be determined as the optimum bit weight.

As described above, the present invention has been described by taking the trench excavator in the underground continuous wall as an example, but the present invention relates to a boring machine such as a boring machine and a large-diameter excavator for a foundation pile. The same can be applied to such a case.

[0021]

As described above in detail, according to the present invention, the "optimum bit load" according to the present invention is determined based on the bit load measurement information, and the excavation thrust is feedback-controlled based on this. As a result, optimum excavation conditions can be set in real time during excavation, and efficient excavation according to the geological properties at the time of excavation is realized.

In addition, since the control is based on a single factor, the control becomes easy, and the automation of the hydraulic operation greatly reduces the burden on the operator.

[Brief description of the drawings]

FIG. 1 is a diagram showing a trench excavation state in an underground diaphragm wall method.

FIG. 2 is a hydraulic control system diagram of bit load control in the method of the present invention.

FIG. 3 is a schematic waveform diagram of an actual bit load.

FIG. 4 is an explanatory diagram of an optimum bit load.

FIG. 5 is an apparatus configuration diagram in a case where a hydraulic indicator is monitored by a camera to measure a return speed of a bit load.

[Explanation of symbols]

Reference Signs List 1 excavator, 2 crawler crane, 3 hanging wire, 4 reel, 5 hydraulic cylinder, 6 plunger, 11 hydraulic sensor, 12 relief valve, 13 hydraulic oil storage tank, 14 hydraulic oil Oil supply path, 17: Computer, 19: Two-hand hydraulic indicator, 20: Maximum value indicating needle, 21
... movable needle, 22 ... camera

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazumi Sakamoto 2-16-2 Minami Kamata, Ota-ku, Tokyo Tone Underground Engineering Co., Ltd.

Claims (3)

[Claims] An excavator measures the bit load acting in the direction of excavation when excavating the ground, and sets an average bit load that maximizes the return speed of the bit load based on the bit load measurement as an optimum bit load. A ground excavation method, wherein the excavation thrust is feedback-controlled so that the actual bit load becomes the optimum bit load. 2. An end of a wire rope suspending an excavator is supported by a plunger of a cylinder, and a hydraulic pressure gauge is installed in a hydraulic oil path supplied to the cylinder to measure an actual bit load. Based on the actually measured bit load, an average bit load that maximizes the return speed of the bit load is determined as an optimum bit load, and the hydraulic pressure of the cylinder is feedback-controlled so that the actual bit load becomes the optimum bit load. And the ground excavation method. 3. An oil pressure indicator is provided in a hydraulic oil path of a hydraulic drive source for applying an excavating thrust, and movement of an indicator needle of the oil pressure indicator is monitored by a camera. The return speed of the bit load is determined from the moving speed of the needle, the average bit load that maximizes the return speed of the bit load is determined as the optimum bit load, and the hydraulic operating source is set so that the actual bit load becomes the optimum bit load. Ground excavation method, wherein the hydraulic pressure of the ground is feedback-controlled.