Protection system for soft soil layer used in geotechnical engineering investigation and construction method thereof

Abstract

The present application relates to the technical field of geotechnical engineering investigation, in particular to a soft soil layer protection system for geotechnical engineering investigation and a building method thereof, which comprises a building pipe, a separation plug, a plug scraping edge, an inflatable air ring, a separation inner shell, a slurry outlet notch and a pressing scraping ring, the building pipe is in a cylindrical pipe shape and has openings at the upper and lower ends, the lower end of the building pipe is provided with the separation plug, the outer surface of the separation plug is fixedly provided with the plug scraping edge, the surface of the plug scraping edge is embeddedly provided with the inflatable air ring, the inside of the building pipe is fixedly provided with the separation inner shell, the surface of the building pipe is provided with the slurry outlet notch, and the slurry outlet notch is located above the separation inner shell; the soft soil layer protection system for geotechnical engineering investigation can avoid the falling of concrete slurry into the bottom of the investigation hole during the building of the protection system, thereby reducing the risk of the investigation hole being blocked.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering investigation technology, specifically to a soft soil layer protection system and its construction method for geotechnical engineering investigation. Background Technology

[0002] Geotechnical engineering investigation refers to the activity of investigating, analyzing, and evaluating the geological, environmental characteristics, and geotechnical engineering conditions of a construction site according to the requirements of a construction project, and preparing investigation documents. During geotechnical engineering investigation, it is necessary to drill exploration holes for sampling. When drilling exploration holes in some soft soil layers, the problem of hole collapse is prone to occur. Therefore, a protective system is needed. For example, Chinese patent application CN214993933U discloses a device for preventing hole collapse in soft soil layers for geotechnical engineering investigation, which describes that: the inner wall of the bottom of the second support is provided with... The hydraulic cylinder has a support three on the bottom outer wall of the second support, and a hollow cylinder on the bottom outer wall of the third support. The hollow cylinder has two or more rectangular holes on its outer circumference. A sliding column is slidably connected to the inner circumference of the hollow cylinder. The outer circumference of the sliding column is threaded with two or more limit plugs. The outer walls of the two or more limit plugs are slidably connected to the inner walls of the two or more rectangular holes. The output end of the hydraulic cylinder has a hollow column, and the bottom end of the hollow column has a discharge rack, which is located on the top outer wall of the sliding column.

[0003] For example, as described in the aforementioned patent document, the existing technology uses the aforementioned equipment to build a protective system. However, in actual operation, there is a risk that mud will flow to the bottom of the exploration hole, causing the bottom of the exploration hole to be blocked by mud. Furthermore, when the soil layer is too soft, the mud-built system may loosen and fall. Summary of the Invention

[0004] The purpose of this invention is to provide a soft soil layer protection system and its construction method for geotechnical engineering investigation, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a soft soil layer protection system for geotechnical engineering investigation, comprising a construction pipe, a separating plug, a plug scraper, an expansion ring, a separating inner shell, a slurry outlet, and a pressure-holding scraper ring. The construction pipe is cylindrical and open at both ends. A separating plug is raised and lowered at the lower end of the construction pipe. A plug scraper is fixedly installed on the outer surface of the separating plug. An expansion ring is embedded in the surface of the plug scraper. A separating inner shell is fixedly installed inside the construction pipe. A slurry outlet is opened through the surface of the construction pipe and is located above the separating inner shell. A pressure-holding scraper ring is sleeved on the outside of the construction pipe. A piston drive structure is provided inside the separating plug, which can control the expansion of the expansion ring. A pressure groove mechanism with telescopic function is provided above the separating plug.

[0006] The outer side of the inner shell is provided with a mud drive mechanism with impact drive function.

[0007] The piston drive structure includes a piston chamber, a piston retaining ring, a piston disc, a piston hydraulic rod, an interlocking channel, and a gas ring inlet. The piston chamber is located on the lower surface of the release seat plug. A piston retaining ring is fixedly installed on the inner wall surface of the piston chamber near the lower part. A piston disc is installed inside the piston chamber, above the piston retaining ring, and the outer surface of the piston disc is in sealing contact with the inner wall surface of the piston chamber. A piston hydraulic rod is installed above the piston disc, and the piston hydraulic rod drives the piston disc to move up and down. An interlocking channel is provided inside the release seat plug. A gas ring inlet is connected to the outer surface of the expansion gas ring. The piston chamber is connected to the gas ring inlet through the interlocking channel.

[0008] The grooving mechanism includes a central rod seat, a hydraulic crossbar, and a grooving frame. The central rod seat is fixedly installed on the upper surface of the separation seat plug. A hydraulic crossbar is fixedly installed on the surface of the central rod seat. The hydraulic crossbar is perpendicular to the axis of the erected pipe. A grooving frame is fixedly installed at the end of the telescopic shaft of the hydraulic crossbar.

[0009] The grooving frame is internally equipped with a grooving roller, and a grooving insert is fixedly mounted on the surface of the grooving roller. A positioning vertical plate is fixedly mounted on the lower surface of the grooving frame. A track rod is fixedly mounted on the surface of the central rod seat. A rod end seat is fixedly mounted on the end of the track rod away from the central rod seat. The rod end seat is fixedly installed on the upper surface of the separation seat plug. The track rod passes through the positioning vertical plate.

[0010] The mud driving mechanism includes a one-way clamp, a conical ring stop, a separator, and a piston driving ring. The one-way clamp is fixedly installed on the outer surface of the inner separator shell. The conical ring stop is conical and elastic. The inner side of the conical ring stop is fixedly installed with the one-way clamp, and the outer side is in contact with the inner wall surface of the construction pipe. The separator shell is installed above the one-way clamp on the outer side of the inner separator shell. The piston driving ring is fixedly installed on the lower edge of the separator and is in sealed contact with the inner wall surface of the construction pipe.

[0011] A slurry inlet pipe is provided through the lower surface of the piston drive ring. A one-way plug is provided to seal the lower end of the slurry inlet pipe. An outer tension spring is provided between the one-way plug and the lower surface of the piston drive ring. A connecting spring is provided between the upper surface of the inner separator shell and the inner surface of the separator shroud. An electromagnet module is fixedly provided on the upper surface of the inner separator shell. The electromagnet module is magnetically attracted to the separator shroud.

[0012] A scraping ring is fixedly installed on the outer surface of the constructed pipe. A lifting installation ring is fixedly installed near the upper end of the outer surface of the constructed pipe. An end seat connecting plate is fixedly installed on the upper surface of the central rod seat. An insertion seat sleeve is fixedly installed on the upper surface of the end seat connecting plate. A seat plug hydraulic cylinder is fixedly installed inside the partition inner shell. The telescopic shaft of the seat plug hydraulic cylinder is inserted and fixed inside the insertion seat sleeve.

[0013] The upper surface of the inner shell of the partition is provided with a through hole for wiring, and the upper surface of the partition cover is provided with an external wiring pipe. The external wiring pipe is provided with a protective outer pipe.

[0014] A method for constructing a soft soil layer protection system for geotechnical engineering investigation, comprising the following steps:

[0015] Step 1: Insert the pipeline into the exploration hole in the soft soil layer, and use grooved inserts to groove the inner wall surface of the exploration hole;

[0016] Step 2: First, the hydraulic crossbar retracts, causing the pressure groove insert to retract. Then, the seat plug hydraulic cylinder retracts, causing the separating seat plug to seal the lower end of the pipeline.

[0017] Step 3: The piston hydraulic rod contracts, causing the expansion ring to expand and seal the area below the gap between the construction pipe and the exploration hole;

[0018] Step 4: Inject mud through the upper opening of the constructed pipe. The mud is discharged through the discharge trough with impact and gradually rises in the gap between the constructed pipe and the exploration hole.

[0019] Step 5: After the mud has initially solidified, control the expansion ring to contract, then move the pipe upwards and pull it out. Use the seated plug scraper to scrape the inner wall of the mud construction system.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The soft soil layer protection system for geotechnical engineering investigation of the present invention can prevent concrete slurry from flowing into the bottom of the exploration hole during the construction of the protection system, thereby reducing the risk of the exploration hole being blocked.

[0022] The groove-pressing mechanism allows for real-time groove pressing of the inner wall of the exploration borehole when the pipe is inserted. This ensures that the slurry adheres to the grooved inner wall of the exploration borehole during the construction of the concrete protection system, improving the stability of the protection system and reducing the risk of the slurry protection body collapsing when the soil is too soft. Furthermore, the groove pressing process is carried out simultaneously with the insertion of the pipe, resulting in high construction efficiency.

[0023] The specially designed mud drive mechanism makes operation more convenient. Simply pour atmospheric pressure mud into the construction pipeline, eliminating the need for external mud injection and pressurization equipment and improving equipment portability. At the same time, when the mud drive mechanism drives the mud to flow out of the discharge trough, it creates an impact wave. This impact wave of the mud allows for a deeper fit between the mud and the groove on the inner wall of the exploration hole, reducing the problem of empty grooves. Furthermore, the lifting and lowering impact of the separator can churn and impact the mud inside the construction pipeline, making the mud more uniformly mixed and preventing mud sedimentation and stratification. Attached Figure Description

[0024] Figure 1 This is a three-dimensional half-sectional schematic diagram of the overall structure of the present invention.

[0025] Figure 2 for Figure 1 Enlarged schematic diagram of region A in the middle.

[0026] Figure 3 for Figure 2 Enlarged schematic diagram of region B in the middle.

[0027] Figure 4 This is a three-dimensional half-section front view of the overall structure of the present invention.

[0028] Figure 5 for Figure 4 Enlarged schematic diagram of region C in the middle.

[0029] Figure 6 This is a schematic diagram of the structure of the present invention.

[0030] Figure 7 This is a structural schematic diagram of the present invention from another angle.

[0031] Figure 8 This is a three-dimensional half-sectional view of the present invention near the front.

[0032] Figure 9 for Figure 8 Enlarged schematic diagram of region D in the middle.

[0033] Figure 10 This is a three-dimensional half-section front view of the present invention near the front.

[0034] Figure 11 for Figure 10 Enlarged schematic diagram of region E in the middle.

[0035] In the diagram: 1. Pipeline installation; 2. Separating the plug; 3. Plug scraper; 4. Expansion ring; 5. Inner shell separator; 6. Slurry outlet; 7. Pressing scraper ring; 201. Piston chamber; 202. Piston retaining ring; 203. Piston disc; 204. Piston hydraulic rod; 205. Interactive cavity; 206. Air ring inlet; 207. Center rod seat; 208. Hydraulic crossbar; 209. Grooving frame; 210. Grooving roller; 211. Grooving insert; 212. Positioning vertical plate; 213. Track guide rod; 214. 501. Smooth pole end seat; 502. One-way clamping edge; 503. Conical ring stopper; 504. Separating cover; 505. Piston drive ring; 506. Grout inlet pipe; 507. One-way plug; 508. Outer tension spring; 509. Connecting spring; 501. Electromagnet module; 101. Scraper ring stopper; 102. Lifting and mounting ring; 215. End seat connecting plate; 216. Inserted seat sleeve; 217. Seat plug hydraulic cylinder; 510. Cable routing through hole; 511. Cable routing external connecting pipe; 512. Protective outer pipe; 8. Soft soil layer. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figures 1 to 11 This invention provides a technical solution: a soft soil layer protection system for geotechnical engineering investigation, comprising a construction pipe 1, a separation plug 2, a plug scraper 3, an expansion ring 4, a partition inner shell 5, a slurry outlet 6, and a pressure-holding scraper ring 7. The construction pipe 1 is a cylindrical tube with openings at both the top and bottom. The separation plug 2 is raised and lowered at the lower end of the construction pipe 1. The plug scraper 3 is fixedly installed on the outer surface of the separation plug 2. The expansion ring 4 is embedded in the surface of the plug scraper 3. The partition inner shell 5 is fixedly installed inside the construction pipe 1. The slurry outlet 6 is opened through the surface of the construction pipe 1 and is located above the partition inner shell 5. The pressure-holding scraper ring 7 is sleeved on the outside of the construction pipe 1. The separation plug 2 has a piston drive structure inside, which can control the expansion ring 4 to expand or contract. A pressure groove mechanism with telescopic function is provided above the separation plug 2.

[0038] The outer side of the inner shell 5 is equipped with a mud drive mechanism with impact drive function.

[0039] The piston drive structure includes a piston chamber 201, a piston retaining ring 202, a piston disc 203, a piston hydraulic rod 204, an inter-cavity channel 205, and a gas ring inlet 206. The piston chamber 201 is located on the lower surface of the release seat plug 2. The piston retaining ring 202 is fixedly installed on the inner wall surface of the piston chamber 201 near the lower part. The piston disc 203 is installed inside the piston chamber 201, located above the piston retaining ring 202, and the outer surface of the piston disc 203 is in sealing contact with the inner wall surface of the piston chamber 201. The piston hydraulic rod 204 is installed above the piston disc 203, and the piston hydraulic rod 204 drives the piston disc 203 to move up and down. The inter-cavity channel 205 is opened inside the release seat plug 2. The outer surface of the expansion gas ring 4 is connected to the gas ring inlet 206. The piston chamber 201 is connected to the gas ring inlet 206 through the inter-cavity channel 205.

[0040] The grooving mechanism includes a central rod seat 207, a hydraulic crossbar 208, and a grooving frame 209. The central rod seat 207 is fixedly installed on the upper surface of the separation seat plug 2. The hydraulic crossbar 208 is fixedly installed on the surface of the central rod seat 207. The hydraulic crossbar 208 is perpendicular to the axis of the construction pipe 1. The grooving frame 209 is fixedly installed at the end of the telescopic shaft of the hydraulic crossbar 208.

[0041] The grooving frame 209 has a rotatable grooving roller 210 inside, and a grooving insert 211 is fixedly installed on the surface of the grooving roller 210. A positioning vertical plate 212 is fixedly installed on the lower surface of the grooving frame 209. A track rod 213 is fixedly installed on the surface of the center rod seat 207. A rod end seat 214 is fixedly installed at the end of the track rod 213 away from the center rod seat 207. The rod end seat 214 is fixedly installed on the upper surface of the separation seat plug 2. The track rod 213 passes through the positioning vertical plate 212.

[0042] The mud driving mechanism includes a one-way clamping rib 501, a conical ring stop 502, a partition cover 503, and a piston driving ring 504. The one-way clamping rib 501 is fixedly installed on the outer surface of the partition inner shell 5. The conical ring stop 502 is conical and elastic. The inner side of the conical ring stop 502 is fixedly installed with the one-way clamping rib 501, and the outer side is in contact with the inner wall surface of the construction pipe 1. The partition cover 503 is installed on the outer side of the partition inner shell 5 above the one-way clamping rib 501. The piston driving ring 504 is fixedly installed on the lower edge of the partition cover 503. The piston driving ring 504 is in sealed contact with the inner wall surface of the construction pipe 1.

[0043] A slurry inlet pipe 505 is provided through the lower surface of the piston drive ring 504. A one-way plug 506 is provided to seal the lower end of the slurry inlet pipe 505. An outer tension spring 507 is provided between the one-way plug 506 and the lower surface of the piston drive ring 504. A connecting spring 508 is provided between the upper surface of the inner separator shell 5 and the inner surface of the separator shroud 503. An electromagnet module 509 is fixedly provided on the upper surface of the inner separator shell 5. The electromagnet module 509 is magnetically attracted to the separator shroud 503. The electromagnet module 509 is composed of a coil and an iron core. It can generate a strong magnet when energized.

[0044] A scraper ring 101 is fixedly installed on the outer surface of the pipe 1. A lifting installation ring 102 is fixedly installed on the outer surface of the pipe 1 near the upper end. An end seat connecting plate 215 is fixedly installed on the upper surface of the center rod seat 207. An insertion seat sleeve 216 is fixedly installed on the upper surface of the end seat connecting plate 215. A seat plug hydraulic cylinder 217 is fixedly installed inside the inner shell 5. The telescopic shaft of the seat plug hydraulic cylinder 217 is inserted and fixed inside the insertion seat sleeve 216.

[0045] A wiring through hole 510 is provided on the upper surface of the inner shell 5. An external wiring pipe 511 is provided on the upper surface of the partition cover 503. A protective outer pipe 512 is provided on the outside of the external wiring pipe 511. The hydraulic control oil circuits of the piston hydraulic rod 204, hydraulic cross rod 208 and seated piston hydraulic cylinder 217 are arranged through the wiring through hole 510 and extend to the outside of the construction pipe 1 through the external wiring pipe 511 and the protective outer pipe 512. Similarly, the power supply line of the electromagnet module 509 is also connected to the outside through the protective outer pipe 512.

[0046] A method for constructing a soft soil layer protection system for geotechnical engineering investigation, comprising the following steps:

[0047] Step 1: Insert the pipe 1 into the exploration hole in the soft soil layer, and perform groove treatment on the inner wall surface of the exploration hole using the groove insert 211;

[0048] Step 2: First, the hydraulic crossbar 208 retracts, causing the pressure groove insert 211 to retract. Then, the seat plug hydraulic cylinder 217 retracts, causing the separation seat plug 2 to seal the lower end of the construction pipe 1.

[0049] Step 3: The piston hydraulic rod 204 contracts, causing the expansion ring 4 to expand, sealing the area below the gap between the construction pipe 1 and the exploration hole;

[0050] Step 4: Inject mud through the upper opening of the constructed pipe 1. The mud is discharged through the discharge trough 6 with impact and gradually rises in the gap between the constructed pipe 1 and the exploration hole.

[0051] Step 5: After the mud has initially solidified, control the expansion ring 4 to contract, then move the pipe 1 upward and pull it out, and use the seat plug scraper 3 to scrape the inner wall of the mud construction system.

[0052] In use, the present invention is fixedly installed with an external lifting control device through the lifting installation ring 102. First, the hydraulic cylinder 217 of the seat plug is extended, causing the separation seat plug 2 to move down. Then, the hydraulic crossbar 208 is extended, causing the grooving roller 210 to spread and move in all directions, aligning the construction pipe 1 with the exploration hole inside the soft soil layer 8 on the same axis. Then, the construction pipe 1 is moved down. During the downward movement of the construction pipe 1, the grooving roller 210 can groove the inner wall surface of the exploration hole through the grooving insert 211.

[0053] After the pipeline 1 is lowered into place, the hydraulic crossbar 208 retracts, causing the pressure roller 210 to retract. Then, the seated piston hydraulic cylinder 217 retracts, and the separating seated piston 2 moves upward, blocking and sealing the lower end of the pipeline 1. At this time, the piston hydraulic rod 204 retracts, driving the piston disc 203 to move, causing the gas in the piston chamber 201 to be squeezed into the expansion ring 4. The expansion ring 4 expands and seals against the inner wall surface of the exploration hole.

[0054] Concrete slurry is poured into the interior of the construction pipe 1 from above. The electromagnet module 509 is supplied with a pulsed current, generating intermittent magnetic force, which drives the partition sleeve 503 to move back and forth. This causes the piston drive ring 504 to move up and down. During the movement of the piston drive ring 504, it can drive the slurry to flow in one direction by cooperating with the one-way blocking plate 506 and the cone ring blocking plate 502, so that the slurry can be ejected from the slurry outlet 6 in an impact wave pattern. The slurry gradually rises in the gap between the construction pipe 1 and the exploration hole, pushing the pressure scraper ring 7 upward. The pressure scraper ring 7 can flatten the slurry, making the slurry evenly distributed, and can apply slight pressure to the slurry, increasing the penetration depth of the slurry into the inner wall of the exploration hole.

[0055] Once the pressure scraper ring 7 is flush with the upper surface of the soft soil layer 8, stop the operation of the electromagnet module 509. After standing for a period of time, once the mud has initially solidified and will not flow, control the piston hydraulic rod 204 to extend, causing the expansion ring 4 to be sucked back and collapsed, hiding in the seat plug scraper ridge 3 to avoid wear on the expansion ring 4. Control the construction pipe 1 to move upward. At this time, through the seat plug scraper ridge 3, the inner wall surface of the constructed concrete system can be scraped and repaired to improve flatness and remove excess material.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A soft soil layer protection system for geotechnical engineering investigation, comprising a pipeline (1), a separation plug (2), a plug scraper (3), an expansion air ring (4), a separation inner shell (5), a slurry outlet (6), and a pressure scraper ring (7), characterized in that: The construction pipe (1) is cylindrical and open at both ends. A separation plug (2) is provided at the lower end of the construction pipe (1). A plug scraper (3) is fixedly provided on the outer surface of the separation plug (2). An expansion ring (4) is embedded in the surface of the plug scraper (3). A partition inner shell (5) is fixedly provided inside the construction pipe (1). A slurry outlet (6) is opened through the surface of the construction pipe (1). The slurry outlet (6) is located above the partition inner shell (5). A pressure scraper ring (7) is sleeved on the outside of the construction pipe (1). A piston drive structure is provided inside the separation plug (2). The piston drive structure can control the expansion ring (4) to expand or contract. A pressure groove mechanism with lateral telescopic function is provided above the separation plug (2).

2. The soft soil layer protection system for geotechnical engineering investigation according to claim 1, characterized in that: The outer side of the inner shell (5) is provided with a mud driving mechanism with impact driving function, so that the mud is discharged in an impact manner.

3. The soft soil layer protection system for geotechnical engineering investigation according to claim 2, characterized in that: The piston drive structure includes a piston chamber (201), a piston retaining ring (202), a piston disc (203), a piston hydraulic rod (204), an interactive cavity (205), and a gas ring inlet (206). The piston chamber (201) is located on the lower surface of the release seat plug (2). The piston retaining ring (202) is fixedly disposed on the inner wall surface of the piston chamber (201) near the lower part. The piston disc (203) is disposed inside the piston chamber (201) and is located on the piston retaining ring (202). Above the piston disc (203), the outer surface of the piston disc (203) is in sealed contact with the inner wall surface of the piston chamber (201). A piston hydraulic rod (204) is provided above the piston disc (203). The piston hydraulic rod (204) drives the piston disc (203) to move up and down. An interactive cavity (205) is provided inside the separator plug (2). An air ring plug (206) is provided on the outer surface of the expansion ring (4). The piston chamber (201) is connected to the air ring plug (206) through the interactive cavity (205).

4. The soft soil layer protection system for geotechnical engineering investigation according to claim 3, characterized in that: The grooving mechanism includes a central rod seat (207), a hydraulic crossbar (208), and a grooving frame (209). The central rod seat (207) is fixedly installed on the upper surface of the separation seat plug (2). The hydraulic crossbar (208) is fixedly installed on the surface of the central rod seat (207). The hydraulic crossbar (208) is perpendicular to the axis of the construction pipe (1). The grooving frame (209) is fixedly installed at the end of the telescopic shaft of the hydraulic crossbar (208).

5. The soft soil layer protection system for geotechnical engineering investigation according to claim 4, characterized in that: The grooving frame (209) is internally rotatably equipped with a grooving roller (210), and a grooving insert (211) is fixedly provided on the surface of the grooving roller (210). A positioning vertical plate (212) is fixedly provided on the lower surface of the grooving frame (209). A track light rod (213) is fixedly provided on the surface of the central rod seat (207). A light rod end seat (214) is fixedly provided at the end of the track light rod (213) away from the central rod seat (207). The light rod end seat (214) is fixedly installed on the upper surface of the separation seat plug (2). The track light rod (213) passes through the positioning vertical plate (212).

6. The soft soil layer protection system for geotechnical engineering investigation according to claim 5, characterized in that: The mud driving mechanism includes a one-way clamp (501), a conical ring flap (502), a separator sleeve (503), and a piston driving ring (504). The one-way clamp (501) is fixedly installed on the outer surface of the inner separator shell (5). The conical ring flap (502) is conical and elastic. The inner side of the conical ring flap (502) is fixedly installed with the one-way clamp (501), and the outer side is in contact with the inner wall surface of the construction pipe (1). The separator sleeve (503) is installed on the outer side of the inner separator shell (5) above the one-way clamp (501). The piston driving ring (504) is fixedly installed on the lower edge of the separator sleeve (503). The piston driving ring (504) is in sealed contact with the inner wall surface of the construction pipe (1).

7. The soft soil layer protection system for geotechnical engineering investigation according to claim 6, characterized in that: A slurry inlet pipe (505) is provided through the lower surface of the piston drive ring (504). A one-way plug (506) is provided to seal the lower end of the slurry inlet pipe (505). An outer tension spring (507) is provided between the one-way plug (506) and the lower surface of the piston drive ring (504). A connecting spring (508) is provided between the upper surface of the inner separator shell (5) and the inner surface of the separator shroud (503). An electromagnet module (509) is fixedly provided on the upper surface of the inner separator shell (5). The electromagnet module (509) is magnetically attracted to the separator shroud (503).

8. The soft soil layer protection system for geotechnical engineering investigation according to claim 7, characterized in that: The outer surface of the construction pipe (1) is fixedly provided with a scraping ring rib (101), and the outer surface of the construction pipe (1) is fixedly provided with a lifting installation ring (102) near the upper end. The upper surface of the center rod seat (207) is fixedly provided with an end seat connecting plate (215), and the upper surface of the end seat connecting plate (215) is fixedly provided with a plug-in seat sleeve (216). The interior of the partition inner shell (5) is fixedly provided with a seat plug hydraulic cylinder (217), and the telescopic shaft of the seat plug hydraulic cylinder (217) is inserted and fixed inside the plug-in seat sleeve (216).

9. The soft soil layer protection system for geotechnical engineering investigation according to claim 8, characterized in that: The upper surface of the inner shell (5) is provided with a through hole (510) for wiring, and the upper surface of the partition cover (503) is provided with an external wiring pipe (511), and the external wiring pipe (511) is provided with a protective outer pipe (512).

10. The method for constructing a soft soil layer protection system for geotechnical engineering investigation according to claim 8 or 9, characterized in that, The method includes the following steps: Step 1: Insert the construction pipe (1) into the exploration hole in the soft soil layer, and perform groove treatment on the inner wall surface of the exploration hole by using the groove insert (211); Step 2: First, the hydraulic crossbar (208) retracts, causing the pressure groove insert (211) to retract. Then, the seat plug hydraulic cylinder (217) retracts, causing the separation seat plug (2) to seal the lower end of the construction pipe (1). Step 3: The piston hydraulic rod (204) contracts, causing the expansion ring (4) to expand, sealing the area below the gap between the construction pipe (1) and the exploration hole; Step 4: Inject mud through the upper opening of the constructed pipe (1), and the mud is discharged through the discharge trough (6) with impact, gradually rising in the gap between the constructed pipe (1) and the exploration hole; Step 5: After the mud has initially solidified, control the expansion ring (4) to shrink, then build the pipe (1) and pull it out. Use the seat plug scraper (3) to scrape the inner wall of the mud construction system.

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