CN113484916A

CN113484916A - Pore pressure observation device for recognizing seabed interface based on natural potential method and working method

Info

Publication number: CN113484916A
Application number: CN202110814070.0A
Authority: CN
Inventors: 刘晓磊; 李星宇; 余和雨; 范智涵; 李伟甲; 陆杨
Original assignee: Ocean University of China
Current assignee: Ocean University of China
Priority date: 2021-07-19
Filing date: 2021-07-19
Publication date: 2021-10-08

Abstract

The invention provides a pore pressure observation device for identifying a seabed interface based on a natural potential method and a working method thereof, wherein the pore pressure observation device comprises a pore water pressure observation system, a seabed interface identification system, an acquisition and power supply system and a support and injection system. The attitude sensor is used for acquiring elevation change data of a seabed interface caused by seabed erosion or siltation, and the attitude sensor is used for correcting the problem that the probe rod cannot reach the preset penetration depth due to inclination, so that the problem of high penetration difficulty of the pore pressure probe rod is solved.

Description

Pore pressure observation device for recognizing seabed interface based on natural potential method and working method

Technical Field

The invention relates to the technical field of seabed pressure observation, in particular to a pore pressure observation device for identifying a seabed interface based on a natural potential method.

Background

Pore water pressure (hereinafter referred to as pore pressure) refers to the pressure of groundwater in soil or rock, and the pressure acts between particles or pores and is divided into static pore pressure and super-static pore pressure. Under the cyclic load of waves, the pore pressure in seabed sediments can be changed dynamically continuously, effective stress is reduced due to pore pressure accumulation, the seabed is liquefied, geological disasters such as seabed deformation and seabed landslide are further induced, and accidents such as unstable collapse of an offshore oil platform, seabed pipeline breakage and the like can be caused. And the pore pressure device is adopted for in-situ observation, so that the truest and most reliable data can be obtained theoretically, and the pore pressure device is used for researching a pore pressure accumulation mechanism in the silty seabed of the yellow river estuary under an extreme storm condition, thereby providing scientific guidance for offshore engineering facility construction, ocean resource development and the like.

At present, pore pressure data measured by pore pressure sensors in pore pressure observation devices at home and abroad are mostly regarded as the pore pressure at a fixed depth from a seabed interface, and influence caused by seabed erosion and deposition is not considered. The multifunctional in-situ observation probe rod for the submarine sediment mainly comprises a multifunctional observation probe rod, wherein multiple parameters are acquired through a static sounding probe, a resistivity measurement module, a pore pressure sensor and the like, and pore pressure data are rarely corrected due to the change of a seabed interface. The change of the seabed interface can cause the difference between the depth of the preset pore pressure sensor and the actual depth to be large, and great errors are caused when the specific scientific problems such as seabed liquefaction depth and the like are researched through pore pressure data.

Disclosure of Invention

Aiming at the technical vacancy of correcting the influence of seabed erosion and siltation, the invention designs the pore pressure observation device for identifying the seabed interface based on the natural potential method.

In order to make up for the defects of the prior art, the invention provides a pore pressure observation device for identifying a seabed interface based on a natural potential method and a working method.

The invention is realized by the following technical scheme: a pore pressure observation device for identifying a seabed interface based on a natural potential method comprises a pore water pressure observation system, a seabed interface identification system, an acquisition and power supply system and a supporting and injection system, and is characterized in that the pore water pressure observation system comprises a pore pressure probe rod, a water inlet hole, a connecting piece, a screw, a permeable stone, a water pressure transmission channel, a pore water pressure sensor, a data transmission and power supply line and a cable channel; the hole pressure probe rod is provided with three sections, water inlet holes are arranged at intervals of 0.5m on the hole pressure probe rod, the water inlet holes penetrate through the wall of the hole pressure probe rod and are communicated with the water pressure transmission channel, permeable stones are embedded in the water inlet holes and are used for pore water to permeate into the water pressure transmission channel, the water pressure transmission channel is fixed in the hole pressure probe rod in a T shape, the vertical section is connected with the water inlet holes through the permeable stones above, the horizontal section is fixed in the rod through the upper wall of the water pressure transmission channel, the lower wall of the water pressure transmission channel and a connecting piece, the upper wall of the water pressure transmission channel is fixed on the rod wall through screws, the left end of the horizontal section is connected with the connecting piece, and a pore water pressure sensor is embedded between the upper wall of the water pressure transmission channel and the lower wall of the water pressure transmission channel and is connected with the right end of the horizontal section of the water pressure transmission channel; a cable channel is reserved in the hole pressure probe rod, the data transmission and power supply line is assembled in the cable channel, the data transmission and power supply line is connected with the right end of the pore water pressure sensor, 8 pore water pressure observation systems are arranged, 6 of the pore water pressure observation systems are positioned in the hole pressure probe rod, the other two pore water pressure observation systems are arranged in the potential rod, and the installation modes are the same;

the seabed interface recognition system comprises a potential rod, an annular solid reference electrode and an attitude sensor; the potential rod is connected with the top of the hole pressure probe rod through a threaded tightening sleeve, a plurality of annular solid reference electrodes are embedded in the surface of the potential rod at equal intervals, an internal cavity of the potential rod is a cable channel, so that data transmission and power supply lines can conveniently connect the annular solid reference electrodes with the data acquisition and power supply cabin, and the attitude sensor is fixed at the upper left part inside the data acquisition and power supply cabin;

the acquisition and power supply system comprises a data acquisition and power supply cabin, a battery pack, a high-precision voltmeter, a data acquisition instrument, a circuit board, a data storage card, an external port, a watertight connector female head and a watertight connector male head; the data acquisition and power supply cabin is internally provided with a battery pack, a high-precision voltmeter, a data acquisition instrument, a circuit board, a data storage card and an external port, the lower end of the data acquisition and power supply cabin is connected with the top end of a potential rod, the battery pack is arranged in the data acquisition and power supply cabin, the high-precision voltmeter and the circuit board are positioned right above the inside of the data acquisition and power supply cabin and are connected with an annular solid reference electrode through a data transmission and power supply line, the high-precision voltmeter and a pore water pressure sensor are both connected with the data acquisition instrument fixed on the upper left side of the high-precision voltmeter and the pore water pressure sensor, and the obtained data are stored in the data storage card in the data acquisition instrument; the top of the data acquisition and power supply cabin is provided with an external port, each section of probe rod is connected by a water tight seal plug, the upper and lower ends of the potential rod and the pore pressure probe rod are respectively made into a watertight plug female head and a watertight plug male head, and the three sections of pore pressure probe rods can be replaced at will;

the supporting and penetrating system comprises a conical tip, a limiting nut, a threaded tightening sleeve, a waterproof gasket, external threads, a drill bit connecting rod, a power transmission wing, a displacement sensor, a barrier strip, a barrier wing and internal threads; the awl point is located the most terminal of device, junction between every section probe rod, the body of rod is inside to be connected by the watertight connector, waterproof packing ring is located the public head department of watertight connector, it is fixed that the outside is tightly overlapped with the screw thread, its inside built-in screw thread that sets up, hole pressure probe rod surface sets up external screw thread, fasten two sections probe rods through the mode of rotation, set up stop nut on the body of rod of screw thread tight cover top, the top design of collection and power supply cabin is the embedding pattern that matches with the drill bit, the drill bit bottom is the drill bit connecting rod, four power transmission wings of surface design at the drill bit connecting rod, can imbed the top of collection and power supply cabin, it supports power transmission wing to be equipped with the fender wing at the inside cabin top of collection and power supply cabin, the right-hand member of fender wing is equipped with the displacement of blend stop limit power transmission wing, the right-hand member of power transmission wing is equipped with displacement sensor and judges the position of power transmission wing.

Preferably, the hole pressure probe rod is 1m long in each section.

Preferably, the potential bar has a length of 2 m.

Preferably, the surface of the potential rod is embedded with a plurality of annular solid reference electrodes at equal intervals, and the distance between every two annular solid reference electrodes is 1 cm.

Furthermore, the annular solid reference electrode is made of a titanium alloy and is made into an annular framework.

Furthermore, the surface of the annular solid reference electrode is coated with 0.1mm-1mm of graphene material, and the thickness of the annular solid reference electrode is 2 mm.

A working method of a pore pressure observation device for identifying a seabed interface based on a natural potential method is characterized by comprising the following steps:

s1: the device is placed on the seabed by a shipborne drilling machine, before the device is placed on the seabed, a probe rod is sleeved into a protective cylinder on a ship, the shipborne drilling machine is connected with the top of a collecting and power supplying cabin through a drill bit connecting rod, a drill bit is embedded into a top cover along a matched notch and then rotates clockwise until the drill bit is blocked by a blocking strip, a power transmission wing is just positioned under the blocking wing, and the blocking wing can support the probe rod to convey the probe rod to the seabed;

s2: after the device is placed into the seabed, the drill bit is rotated clockwise, the power transmission wing of the drill bit drives the rod body to vertically and downwards drill, the drill stops after the drill reaches the depth of 4m, 4m of the rod body penetrates into the seabed, 1m of the rod body is left above the seabed, the annular solid reference electrode of the potential rod occupies about half of the two media of water and soil, the water inlet hole of the pore water pressure sensor is provided with one piece of water positioned above the seabed and used for acquiring hydrostatic pressure, and the rest seven pieces of water are positioned inside the seabed and used for observing the pore pressures at different depths;

s3: after the probe rod is penetrated, the drill bit is rotated anticlockwise, the power transmission wing of the drill bit collides with the barrier strip after rotating for a wing width distance, at the moment, the drill bit does not slide relative to the probe rod, and the upper part of the power transmission wing is not blocked by the barrier wing completely; meanwhile, the displacement sensor is extruded, a signal lamp connected with the displacement sensor on the ship flickers, and the drill bit can be lifted up to be separated from the probe rod for recycling;

s4: after the drill bit is recovered, a diver enters water to check the posture of the probe rod, and if no abnormality exists, the floating ball is bound on the top of the probe rod to position, so that the drill bit is convenient to recover in the later period.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) the method for determining the seabed interface by combining the natural potential and the attitude sensor solves the problem that the subsequent pore pressure data processing is influenced because the position of the pore water pressure sensor buried in the seabed away from the seabed cannot be accurately obtained due to the large elevation change of the seabed interface caused by the erosion and deposition of the seabed under extreme sea conditions. The attitude sensor is used for acquiring elevation change data of a seabed interface caused by seabed erosion or siltation, and the attitude sensor is used for correcting the problem that the preset penetration depth cannot be reached due to the inclination of the probe rod.

(2) The invention combines the principle of offshore drilling, solves the problem of high difficulty in penetration of the hole pressure probe rod, often needs to additionally process a special penetration platform for the penetration of the hole pressure probe rod in the past, greatly increases the cost and causes the difficulty of transportation, can realize penetration and recovery only by specially processing a local drill bit and the top of the collection cabin, saves the cost and is convenient to use and transport.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1: the probe rod forms a front view;

FIG. 2: a cross-sectional view of a pore water pressure observation system;

FIG. 3: a seabed interface identification system schematic diagram;

FIG. 4: a schematic diagram of a collection and power supply system;

FIG. 5: a front view and a cross-sectional view of the rod connector;

FIG. 6: a drill bit attachment schematic;

FIG. 7: in the context of a work flow diagram,

wherein, the corresponding relationship between the reference numbers and the components in fig. 1 to fig. 6 is:

101: bore pressure probe, 102: inlet opening, 103: a connector, 104: screw, 105: permeable stone, 106: hydraulic pressure transmission passage, 107: pore water pressure sensor, 108: data transmission and supply line, 109: cable channel, 110: upper wall of water pressure transmission passage, 111: a lower wall of the water pressure transmission channel;

201: potential bar, 202: annular solid reference electrode, 203: an attitude sensor;

301: data acquisition and power supply cabin, 302: battery pack, 303: high-precision voltmeter, 304: data acquisition instrument, 305: circuit board, 306: data storage card, 307: external port, 308: watertight connector, 309: female water-tight connector, 310: a watertight connector male;

401, cone tip, 402: limit nut, 403: thread tightening sleeve, 404: waterproof gasket, 405: external thread, 406: drill connecting rod, 407: power transmission wing, 408: displacement sensor, 409: barrier strip, 410: a wing; 411: and a thread is arranged inside.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced otherwise than as specifically described herein, and thus the scope of the present invention is not limited by the specific embodiments disclosed below.

The following describes a pore pressure observation device for identifying a seabed interface based on a natural potential method according to an embodiment of the present invention with reference to fig. 1 to 3.

As shown in fig. 1 and 2, the invention provides a pore pressure observation device for identifying a seabed interface based on a natural potential method, which comprises a pore water pressure observation system, a seabed interface identification system, an acquisition and power supply system and a support and penetration system, and is characterized in that the pore water pressure observation system comprises a pore pressure probe 101, a water inlet 102, a connecting piece 103, a screw 104, a permeable stone 105, a water pressure transmission channel 106, a pore water pressure sensor 107, a data transmission and power supply line 108 and a cable channel 109; the hole pressure probe rod 101 is provided with three sections, the hole pressure probe rod 101 is provided with water inlet holes 102 every 0.5m, the water inlet holes 102 penetrate through the rod wall of the hole pressure probe rod 101 and are communicated with a water pressure transmission channel 106, a permeable stone 105 is embedded in the water inlet holes 102 and is used for pore water to permeate into the water pressure transmission channel 106, the water pressure transmission channel 106 is fixed in the hole pressure probe rod 101 in a T shape, the vertical section is connected with the water inlet holes 102 through the permeable stone 105 above, the horizontal section is fixed in the rod through the upper water pressure transmission channel wall 110, the lower water pressure transmission channel wall 111 and a connecting piece 103, the upper water pressure transmission channel wall 110 is fixed on the rod wall through a screw 104, the left end of the horizontal section is connected with the connecting piece 103, and a pore water pressure sensor 107 is embedded between the upper water pressure transmission channel wall 110 and the lower water pressure transmission channel wall 111 and is connected with the right end of the horizontal section of the water pressure transmission channel 106; a cable channel 109 is reserved in the pore pressure probe 101, a data transmission and power supply line 108 is assembled in the cable channel 109, and the data transmission and power supply line 108 is connected with the right end of the pore water pressure sensor 107 for supplying power and transmitting data; the number of the pore water pressure observation systems is 8, 6 of the pore water pressure observation systems are positioned in the pore pressure probe rod 101, and the other two pore water pressure observation systems are arranged in the potential rod 201 in the same installation mode;

the seabed interface recognition system comprises a potential rod 201, an annular solid reference electrode 202 and an attitude sensor 203; the potential rod 201 is connected with the top of the pore pressure probe rod 101 through a threaded tightening sleeve 403, a plurality of annular solid reference electrodes 202 are embedded in the surface of the potential rod at equal intervals, a cavity in the potential rod 201 is a cable channel 109, so that the data transmission and power supply line 108 can conveniently connect each annular solid reference electrode 202 with the data acquisition and power supply cabin 301, and the attitude sensor 203 is fixed at the upper left in the data acquisition and power supply cabin 301;

the acquisition and power supply system comprises a data acquisition and power supply cabin 301, a battery pack 302, a high-precision voltmeter 303, a data acquisition instrument 304, a circuit board 305, a data storage card 306, an external port 307, a watertight connector 308, a watertight connector female head 309 and a watertight connector male head 310; the data acquisition and power supply cabin 301 is internally provided with a battery pack 302, a high-precision voltmeter 303, a data acquisition instrument 304, a circuit board 305, a data storage card 306 and an external port 307, the lower end of the data acquisition and power supply cabin 301 is connected with the top end of the potential rod 201, and the battery pack 302 is arranged in the data acquisition and power supply cabin 301 and used for supplying power to all power consumption components of the probe rod; the high-precision voltmeter 303 and the circuit board 305 are positioned right above the inside of the data acquisition and power supply cabin 301, are connected with the annular solid reference electrode 202 through the data transmission and power supply line 108 and are respectively used for acquiring data and controlling a switch; the high-precision voltmeter 303 and the pore water pressure sensor 107 are both connected with a data acquisition instrument 304 fixed on the upper left of the high-precision voltmeter 303 and the pore water pressure sensor, and the obtained data is stored in a data storage card 306 in the data acquisition instrument 304; the top of the data acquisition and power supply cabin 301 is provided with an external port 307 which can be connected with external equipment for parameter setting and data transmission; the upper end and the lower end of the potential rod 201 and the upper end and the lower end of the hole pressure probe rod 101 are respectively made into a watertight connector female head 309 and a watertight connector male head 310, and the three sections of the hole pressure probe rods 101 can be replaced at will;

the supporting and penetrating system comprises a conical tip 401, a limiting nut 402, a threaded tightening sleeve 403, a waterproof gasket 404, external threads 405, a drill bit connecting rod 406, power transmission wings 407, a displacement sensor 408, a barrier strip 409, barrier wings 410 and internal threads 411; the conical tip 401 is positioned at the tail end of the device, so that the penetration resistance is reduced, and the equipment can be conveniently penetrated; at the joint between each section of the detecting rod, the inner part of the rod body is connected by a watertight connector 308, a waterproof gasket 404 is positioned at the male head 310 of the watertight connector and is used for protecting the connection of the watertight connector 308 and preventing damage, the outer part of the rod body is fixed by a threaded tightening sleeve 403, an internal thread 411 is arranged in the rod body, an external thread 405 is arranged on the surface of the hole pressing detecting rod 101, the two sections of the detecting rods are fastened in a rotating mode, and a limit nut 402 is arranged on the rod body above the threaded tightening sleeve 403 to prevent the threaded tightening sleeve 403 from sliding; the top of the collection and power supply cabin 301 is designed to be an embedded type matched with a drill, the bottom end of the drill is a drill connecting rod 406, four power transmission wings 407 are designed on the surface of the drill connecting rod 406 and can be embedded into the top of the collection and power supply cabin 301, the probe rod is penetrated into the seabed in a drilling mode, a blocking wing 410 is arranged inside the cabin top of the collection and power supply cabin 301 to support the power transmission wings 407, a blocking strip 409 is arranged at the right end of the blocking wing 410 to limit the displacement of the power transmission wings 407, and a displacement sensor 408 is arranged at the right end of the power transmission wings 407 to judge the position of the power transmission wings 407.

Preferably, the hole pressure probe 101 is 1m long and can be separated from each other.

Preferably, the potential bar 201 is 2m in length.

Preferably, the surface of the potential rod 201 is embedded with a plurality of annular solid reference electrodes 202 at equal intervals, and the interval between every two annular solid reference electrodes 202 is 1 cm.

Further, the annular solid reference electrode 202 is made of a titanium alloy and is made into an annular framework.

Further, the surface of the annular solid reference electrode 202 is coated with 0.1mm-1mm of graphene material, and the thickness of the annular solid reference electrode 202 is 2 mm.

s1: the device is placed on the seabed by a shipborne drilling machine, before the device is placed on the seabed, a probe rod is sleeved into a protective cylinder on a ship, the shipborne drilling machine is connected with the top of the acquisition and power supply cabin 301 through a drill bit connecting rod 406, a drill bit is embedded into a top cover along a matched gap and then rotates clockwise until the drill bit is blocked by a barrier 409, a power transmission wing 407 is just positioned under the barrier wing, and at the moment, the barrier wing 410 can support the probe rod to convey the probe rod to the seabed;

s2: after the device is placed into the seabed, the drill bit is rotated clockwise, the power transmission wing 407 of the drill bit drives the rod body to vertically drill downwards, the drill stops after the drill reaches the depth of 4m, so that 4m of the rod body penetrates into the seabed, 1m of the rod body is left above the seabed, the annular solid reference electrode 202 of the potential rod 201 occupies about half of the two media of water and soil, the water inlet hole 102 of the pore water pressure sensor 107 is provided with one water positioned above the seabed and used for acquiring hydrostatic pressure, and the rest seven water inlet holes are positioned inside the seabed and used for observing hole pressures at different depths;

s3: after the probe rod is completely penetrated, the drill bit is rotated in the counterclockwise direction, the power transmission wing 407 of the drill bit collides with the barrier 409 after rotating for a wing width distance, at the moment, the drill bit does not slide relative to the probe rod, and the part above the power transmission wing 407 is not blocked by the barrier 410; meanwhile, the displacement sensor 408 is extruded, a signal lamp connected with the displacement sensor on the ship flickers, and the drill bit can be separated from the probe rod by lifting up at the moment for recycling;

In the description of the present invention, the terms "plurality" or "a plurality" refer to two or more, and unless otherwise specifically limited, the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention; the terms "connected," "mounted," "secured," and the like are to be construed broadly and include, for example, fixed connections, removable connections, or integral connections; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pore pressure observation device for identifying a seabed interface based on a natural potential method comprises a pore water pressure observation system, a seabed interface identification system, an acquisition and power supply system and a supporting and injection system, and is characterized in that the pore water pressure observation system comprises a pore pressure probe rod (101), a water inlet (102), a connecting piece (103), a screw (104), a permeable stone (105), a water pressure transmission channel (106), a pore water pressure sensor (107), a data transmission and power supply line (108) and a cable channel (109); the hole pressure probe rod (101) is provided with three sections, the hole pressure probe rod (101) is provided with a water inlet hole (102) at the position of 0.5m every other, the water inlet hole (102) penetrates through the rod wall of the hole pressure probe rod (101) and is communicated with a water pressure transmission channel (106), a permeable stone (105) is embedded in the water inlet hole (102), the water pressure transmission channel (106) is fixed in the hole pressure probe rod (101) in a T shape, the vertical section is connected with the water inlet hole (102) through the permeable stone (105) above, the horizontal section passes through the upper wall (110) of the water pressure transmission channel, the lower wall (111) of the water pressure transmission channel and the connecting piece (103) are fixed in the rod, the upper wall (110) of the water pressure transmission channel is fixed on the rod wall by a screw (104), the left end of the horizontal section is connected with the connecting piece (103), and the pore water pressure sensor (107) is embedded between the upper wall (110) of the water pressure transmission channel and the lower wall (111) of the water pressure transmission channel and is connected with the right end of the horizontal section of the water pressure transmission channel (106); a cable channel (109) is reserved in the pore pressure probe rod (101), the data transmission and power supply line (108) is assembled in the cable channel (109), the data transmission and power supply line (108) is connected with the right end of the pore water pressure sensor (107), 8 pore water pressure observation systems are arranged, 6 of the pore pressure probe rod are arranged in the pore pressure probe rod (101), and the rest two pore pressure observation systems are arranged in the potential rod (201) in the same installation mode;

the seabed interface recognition system comprises a potential rod (201), an annular solid reference electrode (202) and an attitude sensor (203); the potential rod (201) is connected with the top of the hole pressure probe rod (101) through a threaded tightening sleeve (403), a plurality of annular solid reference electrodes (202) are embedded in the surface of the potential rod at equal intervals, a cable channel (109) is arranged in the cavity inside the potential rod (201), so that data transmission and power supply lines (108) can conveniently connect the annular solid reference electrodes (202) with the data acquisition and power supply cabin (301), and the attitude sensor (203) is fixed at the upper left inside the data acquisition and power supply cabin (301);

the acquisition and power supply system comprises a data acquisition and power supply cabin (301), a battery pack (302), a high-precision voltmeter (303), a data acquisition instrument (304), a circuit board (305), a data storage card (306), an external port (307), a watertight connector (308), a watertight connector female head (309) and a watertight connector male head (310); the high-precision voltmeter (303) and the circuit board (305) are positioned right above the inside of the data acquisition and power supply cabin (301) and are connected with the annular solid reference electrode (202) through a data transmission and power supply line (108), the high-precision voltmeter (303) and the pore water pressure sensor (107) are both connected with the data acquisition instrument (304) fixed on the upper left side of the high-precision voltmeter (303), and the obtained data are stored in the data storage card (306) inside the data acquisition instrument (304); the top of the data acquisition and power supply cabin (301) is provided with an external port (307), each section of probe rod is connected with a water tight joint plug-in (308), the upper end and the lower end of the potential rod (201) and the pore pressure probe rod (101) are respectively made into a watertight connector female head (309) and a watertight connector male head (310), and the three sections of the pore pressure probe rod (101) can be replaced at will;

the supporting and penetrating system comprises a conical tip (401), a limiting nut (402), a threaded tightening sleeve (403), a waterproof gasket (404), external threads (405), a drill bit connecting rod (406), a power transmission wing (407), a displacement sensor (408), a barrier strip (409), a barrier wing (410) and internal threads (411); the cone point (401) is positioned at the tail end of the device, the connecting part between each section of probe rod, the inner part of the rod body is connected by a watertight connector (308), a waterproof gasket (404) is positioned at the male head (310) of the watertight connector, the outer part of the waterproof gasket is fixed by a threaded tightening sleeve (403), an internal thread (411) is arranged in the waterproof gasket, an external thread (405) is arranged on the surface of the hole pressure probe rod (101), two sections of probe rods are fastened by a rotating mode, a limit nut (402) is arranged on the rod body above the threaded tightening sleeve (403), the top of the collection and power supply cabin (301) is designed into an embedded type matched with a drill bit, the bottom end of the drill bit is a drill bit connecting rod (406), four power transmission wings (407) are designed on the surface of the drill bit connecting rod (406) and can be embedded into the top of the collection and power supply cabin (301), and a blocking wing (410) is arranged inside the top of the collection and power supply cabin (301) to support the power transmission wings (407), the right end of the blocking wing (410) is provided with a blocking strip (409) for limiting the displacement of the power transmission wing (407), and the right end of the power transmission wing (407) is provided with a displacement sensor (408) for judging the position of the power transmission wing (407).

2. The pore pressure observation device for identifying the seabed interface based on the natural potential method as claimed in claim 1, wherein the pore pressure probe (101) is 1m long per section.

3. The pore pressure observation device for identifying the seabed interface based on the natural potential method is characterized in that the length of the potential rod (201) is 2 m.

4. The pore pressure observation device for identifying the seabed interface based on the natural potential method is characterized in that a plurality of annular solid reference electrodes (202) are embedded in the surface of the potential rod (201) at equal intervals, and the interval between every two adjacent annular solid reference electrodes (202) is 1 cm.

5. The pore pressure observation device for identifying the seabed interface based on the natural potential method as claimed in claim 1 or 4, wherein the annular solid reference electrode (202) is made of titanium alloy and is made into an annular framework.

6. The pore pressure observation device for identifying the seabed interface based on the natural potential method is characterized in that the surface of the annular solid reference electrode (202) is coated with 0.1-1 mm of graphene material, and the thickness of the annular solid reference electrode (202) is 2 mm.

7. The working method of the pore pressure observation device for identifying the seabed interface based on the natural potential method as claimed in claims 1 to 6, is characterized by comprising the following steps:

s1: the device is placed on the seabed by a shipborne drilling machine, before the device is placed on the seabed, a probe rod is sleeved into a protective cylinder on a ship, the shipborne drilling machine is connected with the top of a collection and power supply cabin (301) through a drill bit connecting rod (406), a drill bit is embedded into a top cover along a matched gap and then rotates clockwise until the drill bit is blocked by a blocking strip (409), a power transmission wing (407) is just positioned under the blocking wing, and at the moment, the blocking wing (410) can support the probe rod to convey the probe rod to the seabed;

s2: after the device is placed into the seabed, the drill bit is rotated clockwise, the power transmission wing (407) of the drill bit drives the rod body to vertically and downwards drill, the drill stops after the rod body drills to the depth of 4m, so that the rod body has the depth of 4m penetrating into the seabed, 1m is left above the seabed, the annular solid reference electrode (202) of the potential rod (201) occupies about half of the two media of water and soil, the water inlet hole (102) of the pore water pressure sensor (107) is provided with one water positioned above the seabed and used for acquiring hydrostatic pressure, and the rest seven water inlet holes are positioned inside the seabed and used for observing pore pressures at different depths;

s3: after the probe rod is penetrated, the drill bit is rotated anticlockwise, the power transmission wing (407) of the drill bit collides with the barrier (409) after rotating for a wing width distance, at the moment, the drill bit does not slide relative to the probe rod, and the upper part of the power transmission wing (407) is not blocked by the barrier wing (410); meanwhile, the displacement sensor (408) is extruded, a signal lamp connected with the displacement sensor on the ship flickers, and the drill bit can be separated from the probe rod by lifting up at the moment for recycling;