JPS60129679A - Sea bottom soil survey apparatus - Google Patents

Abstract

PURPOSE:To stably survey the surface layer of the sea bottom with high resolving power by an ultrasonic wave and to make it possible to simultaneously surveying soil and the surface hardness of the sea bottom in connection with each other, by loading an ultrasonic transmitting receiving apparatus and a survey plow to a sea bottom slider. CONSTITUTION:A survey plow 5 revolvable by a hydraulic operation apparatus 3 and an ultrasonic transmitting receiving apparatus 7 are loaded to a sea bottom slider 1 forming a sleigh body. The sea bottom slider is slid along the sea bottom and an ultrasonic wave of 15-20kHz is emitted to the surface layer part of the sea bottom from the ultrasonic transmitting receiving apparatus 7 while the reflected wave is received by said apparatus 7 to send electric signal information to a tugboat. In addition, the survey plow 5 is thrusted into the surface layer part of the sea bottom and allowed to advance while plows soil to survey the hardness of the sea bottom and, if there is an obstacle, the survey plow 5 is avoided therefrom by hydraulic revolving action. Therefore, the soil of the surface layer part can be surveyed with high resolving power because an ultrasonic wave is directly transmitted to and reflected from the surface layer part of the sea bottom and the change in soil and surface hardness can be simultaneously surveyed in connection with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical field to which the invention pertains The present invention relates to a seabed soil surveying device that surveys the soil of the seabed while sliding on the seabed.

(b) Conventional technology and its problems When burying submarine cables, it is necessary to conduct a survey of the seabed soil in advance.

Conventional seabed soil investigation methods involve emitting high-frequency ultrasonic waves toward the surface of the seabed from an ultrasonic transducer attached to a research vessel floating on the sea, or from an ultrasonic transducer towed underwater by a research vessel. The submarine soil was investigated by receiving the reflected waves from the seabed surface, and then the hardness of the seabed surface was investigated by towing a submarine glider equipped with a survey plow and being towed by a ship.

However, the conventional method described above has the following problems. In other words: 1) The ultrasonic transmitter/receiver is located far from the seabed, and high-frequency ultrasonic waves are likely to be attenuated in the seawater during propagation. It was difficult to survey the surface layer with high resolution, and because the distance to the seabed was not constant, it was difficult to conduct stable surveys.

2) The seabed soil survey using ultrasonic waves and the hardness survey of the seabed surface using a survey plow had to be conducted separately, which was inefficient and at the same time made it difficult to properly correlate the two.

(c) Purpose of the Invention The present invention has been made in view of the above-mentioned conventional circumstances, and makes it possible to investigate the surface layer of the seabed with high resolution and stably using ultrasonic waves, and to investigate changes in the soil quality of the surface layer of the seabed. The purpose of the present invention is to provide a seabed soil investigation device that enables investigation by associating seabed surface hardness investigation with seafloor surface hardness investigation.

(d) Structure of the Invention The submarine soil surveying apparatus according to the present invention is equipped with an ultrasonic transducer with a frequency of 15 to 20 KH2 for surveying the submarine soil on a submarine sliding body equipped with a plow.

This allows ultrasonic waves to be emitted directly from close range to the seabed surface, resulting in almost no attenuation in the seawater, making it possible to investigate the soil quality of the seabed surface with high resolution using high-frequency ultrasound waves. At the same time, it is possible to conduct a survey of the hardness of the seabed surface using a survey plow while also responding to a soil survey of the seabed surface layer using ultrasonic waves.

(e) Embodiments of the invention Preferred embodiments of the invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a submarine soil investigation device according to the present invention. - In Figure 1, 1 is the main body of the submarine gliding body, which is equipped with the following devices for seabed investigation.

2 is a signal processing device that operates each onboard device based on signal commands from the tugboat, and conversely communicates the operating status of each device to the tugboat.

3 is a hydraulic pump unit that supplies hydraulic oil to each hydraulic operating device.

4 is a ground running meter that detects the distance traveled by the submarine sliding body.

3-5 is a survey plow that excavates the seabed surface and examines its hardness.The details will be described later.

6 is a mud sampling device that collects sample mud from the seabed.

7 is an ultrasonic wave transmitter/receiver for investigating the soil quality of the surface layer of the seabed, and the details will be described later.

1O is an underwater television device for monitoring the conditions on the seabed of submarine soil survey equipment.

11 is a balance weight to maintain the weight balance of the entire submarine soil survey device.

Reference numeral 12 denotes a tow point moving device for moving the hanging point to maintain and maintain the device in a horizontal state when installing the submarine soil survey device on the seabed or removing it from the seabed.

15 is a compass that detects the relative orientation between the tugboat and the submarine soil survey device.

'16 is an inclinometer for detecting longitudinal and lateral inclinations on the seabed of submarine soil survey equipment.

'17 is a grounding detector that confirms the grounding of submarine soil survey equipment to the ocean floor.

'18 is a hydraulic valve unit i for controlling each hydraulically operated device.
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4- 19 is a hydraulic accumulator for pressure adjustment of the hydraulic operating circuit.

23 is a towing fitting that connects the submarine soil survey device to the CAT cable described later.

24 is a submarine with a built-in power transmission circuit and electric signal transmission circuit □
This is a C'AT cable for towing soil survey equipment.

The ultrasonic transducer 7 above is installed at a height of about 50 cm from the bottom of the main body at the center of the front part of the main body 1, and has a directivity width of about 20 degrees toward the seabed surface and a frequency range of 15 to 20 +-12. It emits ultrasonic waves, and at the same time receives reflected waves from the seabed surface, transmits them to the tugboat as electrical signal information, and displays them on a shipboard operation console (not shown).

By mounting the ultrasonic transducer on the submarine sliding body in this way, the attenuation caused by the propagation of ultrasonic waves through seawater is almost eliminated, making it possible to set the frequency as high as 15 to 20 KH2. The measurement resolution can be increased. By using the above frequency, it is possible to investigate up to 5 meters below the seabed with a resolution of approximately 30C1Il or less.

FIG. 2 is a side view showing the structure and operation of the research vessel 5 attached to the rear of the seabed soil investigation apparatus according to the present invention. The investigation shelf main body 25 is pivotally connected to a hinge bin 29 at the end of a plow lever 28 which rotates around a fulcrum 27 by a hydraulic cylinder 26 for investigation plowing. It can be raised and lowered, and takes the position shown by the solid line in Figure 2 during seabed excavation. The research shelf body 25 is also rotatable about the hinge bin 29 by actuation of a protective hydraulic cylinder 30. Survey shelf body 25 when excavating the seabed
The drag force F applied to the cutting edge generates a rotational moment around the hinge bin 29 and applies a pressing load to the protective hydraulic cylinder 30. The support part 31 of the protective hydraulic cylinder 30 is configured to be movable in the axial direction of the protective hydraulic cylinder, and is mounted on the plow lever 28 via a load cell 32 to the fixed block 3.
It is facing 3. When a pressing load is applied to the protective hydraulic cylinder 30 due to the drag force F exerted on the bridge body 25, the protective hydraulic cylinder pushes the load cell 32, and the load cell 3
2 detects the pressing force. The detected pressing force is transmitted to the tugboat, and a control device on the tugboat calculates it and monitors the drag force F. When the drag force F on the cutting edge of the research shelf body increases abnormally and exceeds the set value due to collision with an obstacle on the seabed, the oil pressure inside the protective hydraulic cylinder 3O rises and the person installed in the hydraulic circuit A relief valve (not shown) opens, the piston of the protective hydraulic cylinder 30 retreats, and the hydraulic fluid returns to the hydraulic pump units 1-3. As a result, the investigation shelf main body 25 can be rotated to the position 25a shown by the dashed line in FIG. 2, and overload can be avoided. After the investigation shelf body 25 rotates to avoid overload, the investigation plow lifting hydraulic cylinder 26 is operated to raise the investigation shelf body 25, and the piston of the protective hydraulic cylinder 30 is extended, as shown in FIG. It is possible to take a posture 25b indicated by a chain line. Subsequently, the investigation shelf body 25 is lowered again to the seabed excavation position by the hydraulic cylinder 26, so that excavation can be restarted. By providing a relief valve in the hydraulic circuit of the protective hydraulic cylinder 3O in this way, even if the survey shelf body collides with a submarine obstacle, the survey shelf body can avoid the submarine obstacle regardless of the operation of the hydraulic pressure i. I can do it.

7- (F) Effects of the Invention As described above, the submarine soil survey device according to the present invention is equipped with an ultrasonic transducer with a frequency of 15 to 20 KHz for surveying the submarine soil on a submarine sliding body equipped with a survey vessel. . As a result, high-frequency ultrasound waves are emitted directly to the seabed surface without propagating through the seawater, and reflected waves from the seabed surface can also be received almost directly, allowing for high-resolution and stable investigation of the soil quality of the seabed surface. At the same time, it is possible to simultaneously and directly correlate changes in the soil quality of the seabed surface with changes in the hardness of the seabed surface. Therefore, surveys that were conventionally carried out in two batches can be conducted simultaneously, and the hardness can be investigated using a research vessel only when a change in seabed soil quality is detected by ultrasonic surveys, improving the efficiency of surveys. can do.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a submarine soil survey device according to the present invention;
The figure is a side view showing the configuration and operation of a research vessel attached to a seabed soil investigation device according to the present invention. 5... Research vessel 7... Ultrasonic transducer 8-

Claims (4)

[Claims] (1) Frequency 15 to 20 for seabed soil investigation, )-1
A seabed soil surveying device for surveying seabed soil while sliding on the seabed, characterized in that the ultrasonic transducer of item 2 is mounted on a seabed sliding body equipped with a survey spade. (2) The submarine soil investigation device according to claim 1, wherein the survey plow is equipped with an escape mechanism for dealing with submarine obstacles. (3) The seabed soil type according to claim 2, wherein the relief mechanism comprises a hydraulic cylinder equipped with a relief valve in a hydraulic circuit for rotating the survey plow around the support bin. Investigation equipment. (4) The survey plow is provided at the rear of the submarine sliding body, and the ultrasonic transducer is mounted at the front of the submarine sliding body. Seabed soil survey equipment.・