A method for drilling into a topsoil layer by a geological drilling rig

Abstract

The application discloses a geological drilling machine drilling topsoil layer construction method, which adopts a dry drilling construction method combining dry drilling and wet drilling in the geological drilling machine rotary drilling construction; the geological drilling machine drilling topsoil layer construction method is suitable for strata including sedimentary soil layers and backfill soil layers; drilling construction is performed by submerging drilling tools in a drilling hole with cooling water; the cooling water can cool and lubricate the drilling tools; the drilling hole internal circulation is performed by mud pumps to extract cooling water; the method can avoid serious flushing of the hole wall by the flushing liquid, makes the hole wall more stable, reduces the hole collapse phenomenon, ensures the drilling engineering quality and use function, avoids the flushing liquid in circulation from washing the topsoil layer core, makes the core integrity good, and increases the core taking rate; there is no core loosening or loss phenomenon; the working time of the mud pump is reduced, the equipment diesel oil consumption or electric power loss is reduced, the drilling construction cost is saved, the construction process is clean and environmentally friendly, and good social and economic benefits are generated.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and in particular to a method for drilling topsoil layers using a geological drilling rig. Background Technology

[0002] Geological drilling is a technique that uses geological drilling rigs to drill holes and extract core samples to obtain information about the geological conditions of underground soil and rocks. Geological drilling is mainly used in mineral resource exploration, geological data investigation, groundwater resource exploration, and environmental geology. By drilling, geological drilling can obtain information about underground soil, rocks, and hydrogeology, facilitating a better understanding of strata thickness, underground geological structures, rock properties, groundwater levels, and mineral resources. Geological drilling is currently an important geological exploration technique for investigating underground strata, and it has significant application value in the study of groundwater resources, mineral resources, geological structures, and the geological environment, making it a crucial means of geological exploration. Through geological drilling, the properties of underground soil, rock strata, and hydrology can be understood, including thickness, composition, occurrence, strike, properties, distribution, depth, and aquifers, providing important scientific research basis for geological exploration; and providing crucial information for geological exploration, environmental geological investigation, mineral resource development, and engineering construction geological surveys. At the same time, geological drilling can also obtain information on mineral resources, such as the distribution, reserves, and quality of mineral deposits, providing technical support for the development of mineral resources.

[0003] Geological drilling is mainly divided into two types: core drilling and non-core drilling. Core drilling, also known as solid core drilling, involves drilling a hole using a geological drilling rig, extracting rock cores during the process, and obtaining core samples. Geologists then further analyze the cores to obtain information such as lithology, stratigraphic structure, and geological age. The working principle of core drilling is rotary drilling, where drilling relies on the rotational motion of the drill bit to cut into the rock strata, shearing and breaking the rock to form a hole.

[0004] Core drilling is a type of wet reverse circulation drilling. During wet reverse circulation drilling, cooling water erodes the topsoil core, causing it to be damaged and resulting in poor core integrity and low core recovery rate. Non-core drilling is a type of dry drilling. During dry drilling, issues such as drill bit jamming and drill bit blockage are prone to occur, and the borehole wall is eroded, leading to borehole collapse. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for drilling topsoil layers using a geological drilling rig. This method employs a "dry drilling" technique, combining dry and wet drilling methods found in rotary drilling. By utilizing a drilling operator for "dry drilling," the severe erosion of the borehole wall by flushing fluid is avoided, resulting in a more stable borehole wall, reduced borehole collapse, and ensured drilling quality and functionality. Furthermore, it avoids the erosion of the topsoil core by circulating flushing fluid, ensuring good core integrity, high core recovery rate, and no loose or missing core samples.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for drilling topsoil layers using a geological drilling rig, comprising a dry drilling method combining dry and wet drilling techniques in rotary drilling operations; including the following steps:

[0008] S1. Preparations before starting the drilling rig;

[0009] S2. Start the power unit 1, engage the clutch, and place the transfer case handle in the winch position to start the winch. Use the winch to lower the drill bit first, then the drill rod, to prepare to start drilling.

[0010] S3. Before drilling, cooling water is supplied through a high-pressure hose of a mud pump. The cooling water flows from the drill bit into the borehole, filling the core tube and submerging the drill bit. The rotary head is driven to drive the active drill rod. The active drill rod drives the drill rod and drill bit in the hole to rotate, so that the drill bit can quickly cut into the soil layer of the surface soil layer for dry drilling.

[0011] S4. When the drilling tool has been working for a period of time and the drilling length is close to the core tube length, or the drilling tool is ready to be pulled out, the drilling tool needs to be pulled out and the core is taken out of the core tube. Pulling out the drilling tool requires taking out all the drill rods and drilling tools out of the borehole in sequence.

[0012] S5. Core samples are taken using a core sampling tool. During the core sampling process, the mud pump is connected to the drill pipe connector of the drill bit. Cooling water is injected through the mud pump to fill the drill bit space. The water pressure is used to squeeze the soil core in the drill bit, causing the topsoil core to fall out of the core tube.

[0013] S6. Core samples taken from the core tube are placed parallel to each other in the core box, and the number of cycles is clearly marked. The core samples are clearly marked, including the borehole number, cycle number, box number, total number of boxes, borehole top elevation, and location on the engineering structure. The core samples are sorted, packed, and numbered in sequence.

[0014] S7. When groundwater is first encountered in all boreholes, the water level is measured. Combined with regional hydrological data, the burial status and variation range of groundwater at the site are investigated, and the hydrogeological conditions of the site are analyzed.

[0015] S8. Proceed to the next dry drilling operation; during drilling operations, each cycle from drilling down to core extraction is called a cycle.

[0016] Furthermore, the preparatory work before starting the drilling rig in step S1 includes: checking the oil and diesel levels of the drilling rig's diesel power unit 1, the lubricating oil level of the gearbox, and checking that all connecting parts are securely installed; during drilling rig commissioning, all rotating parts operate normally, and the switches start flexibly and reliably.

[0017] Furthermore, the process of operating the drill string using a winch in step S2 is as follows: when the winch lifts the drill string, release the brake and tighten the release brake; when lowering the drill string, release the lifting brake and partially or completely release the brake; when braking the drill string, release the lifting brake and operate the brake handle to gradually brake the drum; finally, tighten the connection between the drill rod connector and the active drill rod connector of the entire drill string set, lock the mechanical chuck, and prepare to start drilling.

[0018] Furthermore, in step S3, the high-pressure hose of the mud pump is connected to a water tap to supply cooling water, which can cool the drilling tools and lubricate them.

[0019] Furthermore, in step S3, when it is necessary to change the drilling speed during dry drilling, the clutch must be disengaged first to stop the drill bit from rotating, then the corresponding speed gear is adjusted through the gearbox, and finally the clutch is engaged to continue drilling.

[0020] Furthermore, in step S5, the core sampling tool is a carbide drill bit with a core tube, a head, and a drill rod connector.

[0021] Furthermore, in step S5, during the core extraction process, the core extraction rate of the fill layer is not less than 80%, and the core extraction rate of the soil layer is not less than 90%.

[0022] Furthermore, in step S7, the water level of all boreholes is measured when groundwater is first encountered, and the borehole water level is observed 24 hours after the borehole is closed.

[0023] Furthermore, in order to ensure the quality requirements of the drilling process, the drilling rig is used to measure the inclination every 5m during the drilling process, and the inclination of the hole cannot exceed 3º within every 100m.

[0024] The beneficial effects of this invention are:

[0025] This geological drilling rig employs a dry drilling method combining dry and wet techniques, similar to rotary drilling in geological drilling. The drilling fluid used for flushing the topsoil layer is cooling water, which cools the drill bit and tools and provides lubrication. Dry drilling requires less cooling water; the supply only needs to fill the core tube and submerge the drill tools. Furthermore, the cooling water does not require lubricating media, making the process clean and environmentally friendly. Dry drilling avoids erosion of the topsoil core by cooling water, preventing damage and ensuring good core integrity and high core recovery rate. With dry drilling, the operator can control the rig according to the specific site conditions, ensuring smooth drilling and providing excellent operability and safety while also improving drilling efficiency. Because the operator manually operates the rig, issues like drill bit jamming and blockage are less likely to occur. Dry drilling also eliminates the need for the mud pump to continuously circulate cooling water within the hole, saving on drilling costs.

[0026] In summary, this geological drilling method for drilling topsoil layers is safe and practical, solving the problems of low drilling efficiency, avoiding drill bit jamming, and preventing drill bit burning in topsoil geological drilling, thus generating good social and economic benefits. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart of the construction method for drilling topsoil with this geological drilling rig;

[0029] Figure 2 This is a schematic diagram of the side structure of the drilling rig;

[0030] Figure 3 This is a schematic diagram of the front of the drilling rig.

[0031] Figure 4 This is a schematic diagram of the drill pipe structure;

[0032] Figure 5 This is a structural diagram of the drilling tool;

[0033] Figure 1—In the diagram, 1—Power unit, 2—Frame slide rail, 3—Clutch, 4—Gearbox, 5—Winder, 6—Vertical shaft, 7—Mechanical chuck, 8—Active drill rod, 9—Swivel, 10—Heavy crane, 11—Drill tool hauler, 12—Drill tower, 13—Rotator, 14—Transfer box, 15—Transfer box handle, 16—Wire rope, 17—Overflow valve pressure regulating handle, 18—Drill rig movement reversing valve handle, 19—Vertical shaft lifting reversing valve handle, 20—Gearbox handle, 21—Orifice plate, 22—Drill rod, 23—Drill tool, 24—Drill rod connector, 25—Head, 26—Core tube, 27—Drill bit. Detailed Implementation

[0034] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] In response to the problems of cooling water eroding the topsoil core during wet forward and reverse circulation drilling, resulting in poor core integrity, low core recovery rate, and issues such as drill bit jamming, drill bit blockage, and borehole collapse caused by erosion of the borehole wall, this embodiment provides a geological drilling rig drilling method for topsoil layers.

[0036] like Figure 1 As shown, the drilling method for the geological drilling rig to penetrate the topsoil layer includes the following steps:

[0037] S1 construction preparation: such as Figure 2 As shown in Figure 5, before starting the drilling rig, the operator should check the oil and diesel fuel levels in the diesel engine 1 and the lubricating oil level in the gearbox 4, and ensure that all connections are securely fastened. Only after confirming everything is normal can the rig be started. During rig commissioning, all rotating parts must operate normally, and the switches must start flexibly and reliably. The drilling rig should run unloaded for ten minutes to confirm normal operation and no problems before drilling operations can commence.

[0038] S2 Drilling Down: (e.g., ...) Figure 2As shown in Figure 5, start the power unit 1, engage the clutch 3, and power is transmitted to the gearbox 4 and transfer case 14. Place the transfer case handle 15 in the hoisting position to enable the winch 5 to operate. The left handle of the winch 5 is the lifting brake, and the right handle is the braking brake. First, lower the drill string 23. Operate the right handle of the winch 5 to lower the wire rope 16. Under gravity, the wire rope 16 drives the overhead crane 10 to rotate. The overhead crane 10 is positioned on top of the drilling rig 12. Lower the drill string traction device 11 and use it to secure the drill string 23. Operate the left handle of the winch 5 to wind up the wire rope 16, lifting the drill string 23 so that it is vertical and aligned with the borehole opening. Operate the right handle of the winch 5 to lower the drill string 23 into the borehole. Use a fork to secure the drill string 23 to the borehole opening plate 21. Release the traction device 11. 1. The drill string jack 11 engages the drill rod 22. The left handle of the winch 5 is operated to lift the drill rod 22 and lower it to the threaded position of the drill string connector 28. After connecting the threads of the drill string connector, the threads of the drill rod connector 24 are tightened with the fork. The right handle of the winch 5 is operated to lift the drill rod 22 and the drill string 23. After removing the fork, the right handle of the winch 5 is operated to lower the entire drill string 23 into the borehole. During the lowering process, the drill rod 22 is continuously added until the length of the entire drill string 23 is close to the borehole depth and the drill bit 27 is close to the bottom of the hole. The addition of the drill rod 22 is then stopped. Operate the drilling rig to move the reversing valve handle 18 upwards, and at the same time operate the overflow valve pressure regulating handle 17 to move the drilling rig through the frame slide 2. When the drilling rig moves to the head position, align the active drill rod 8 with the drill rod 22 joint in the borehole, connect and tighten the drill rod joint 24 of the complete set of drilling tools 23 with the active drill rod 8 joint, lock the mechanical chuck 7, and prepare to start drilling.

[0039] S3 drilling: The advance per pass in the soil layer should not exceed 1m. For example... Figure 2As shown in Figure 5, before drilling, connect the high-pressure hose of the mud pump to the water tap 9, tighten the threads, and start the mud pump to supply cooling water through the water tap 9. The cooling water is supplied to the drill rod 22 from inside the active drill rod 8, flows from inside the drill rod 22 to the drill string 23, from the drill string 23 to the drill bit 27, and from the drill bit 27 to the borehole. The cooling water fills the core tube 26 and submerges the drill string 23. Then, turn off the mud pump to stop supplying cooling water. The cooling water serves to cool and lubricate the drill string 23. Engage the clutch 3, and power is transmitted to the gearbox 4, then to the transfer case 14. Operate the transfer case handle 15 to the rotary position. The drive rotary head 13 drives the active drill rod 8, which in turn drives the drill rod 22 and drill string 23 in the hole to rotate. The pressure regulating handle 17 of the overflow valve is operated to increase the hydraulic pressure in the hydraulic system. Simultaneously, the vertical shaft feed control valve handle 21 is operated downwards, causing the vertical shaft 6 of the drilling rig to move downwards, driving the drill rod 22 and drill string 23 downwards, allowing the drill bit 27 to quickly cut into the topsoil layer. When the drill bit 27 encounters difficulty in cutting into the soil layer or the load on the power unit 1 increases, the vertical shaft feed control valve handle 21 is operated upwards, causing the vertical shaft 6 of the drilling rig to move upwards, driving the drill rod 22 and drill string 23 upwards. The active drill rod 8 moves upwards by 20-50 cm, moving the movable drill string 23 upwards. The movable drill string 23 allows cooling water in the borehole to enter the bottom of the borehole, cooling the drill bit 27 and providing lubrication. Simultaneously, it allows the power unit 1 to return to normal load operation. Next, operate the vertical spindle feed control valve handle 21 downwards, causing the drilling rig vertical spindle 6 to move downwards, driving the drill rod 22 and drill string 23 downwards, allowing the drill bit 27 to quickly cut into the soil layer for dry drilling. During the dry drilling process, repeatedly operate the vertical spindle feed control valve handle 21 up and down; moving the drill string 23 upwards and downwards to cut into the strata. As the drill string 23 continues to drill, the hole depth increases, and the drill rod 22 extends downwards continuously. When the remaining length on the rig reaches zero, it is necessary to add a short drill rod 22 to increase the total length of the drill rod 22.

[0040] During drilling, if it is necessary to change the drilling rig speed, first disengage clutch 3 to stop the drill bit 23 from rotating, then move the gearbox handle 20 to the corresponding low-speed gear. After adjusting the drilling rig speed, engage clutch 3 to continue drilling. When performing rotary drilling, to change the drilling rig speed, clutch 3 must be disengaged first, and then the gearbox handle 20 must be moved to change the speed.

[0041] S4 Drilling: (e.g., ...) Figure 2As shown in Figure 5, after drilling with drill string 23 for a period of time, when the drilling footage approaches the length of the core tube 26 or reaches the drilling rig lifting requirement, drill string 23 needs to be extracted to remove the core from the core tube 26. Drilling requires sequentially removing all drill rods 22 and drill string 23 from the borehole. When the core extraction requirement is met, disengage clutch 3 to stop drill string 23 from rotating. Operate the vertical spindle feed control valve handle 21 upwards, causing the drilling rig vertical spindle 6 to move upwards, driving drill rods 22 and drill string 23 upwards. The maximum upward stroke is 50cm. Operate winch 5 to lift the drive drill rod 8, release mechanical chuck 7, and operate the vertical spindle feed control valve handle 21 downwards. The drilling rig vertical spindle 6 moves downwards until mechanical chuck 7 reaches the drilling rig head, stopping the downward movement. Move mechanical chuck 7 to lock the drive drill rod 8, and operate the vertical spindle feed control valve handle 21 upwards. The vertical shaft 6 of the drilling rig moves upward, driving the drill rod 22 and drill string 23 upward. The vertical shaft 6 is moved up and down repeatedly until the connector 28 of the active drill rod 8 protrudes from the borehole, reaching approximately 10cm above the borehole opening plate 21. The vertical shaft 6 is then stopped from moving upward. The winch 5 is used to lift the active drill rod 8, and the mechanical chuck 7 is released. The winch 5 is used to lift the active drill rod 8 and drill string 23, and the connector 24 of the drill rod is held in place by a fork. The winch 5 is then used to lower the entire drill string 23 until the fork contacts the borehole opening plate 21. A disassembly tool is used to hold the connector of the active drill rod 8 in place by a fork. The fork is manually moved to loosen the threads of the connector of the active drill rod 8, thus separating the connection between the active drill rod 8 and the drill rod 22. Operate the drilling rig movement reversing valve handle 18 downwards, and simultaneously operate the overflow valve pressure regulating handle 17 to move the drilling rig through the frame slide rail 2, moving the drilling rig to the tail position, aligning the overhead crane 10 and the drill string 23 in a straight line. Release the drill string traction device 11, operate the right handle of the winch 5 to lower the drill string traction device 11, and when the drill string traction device 11 reaches the drill rod connector 24 position, stop lowering the drill string traction device 11, and use the drill string traction device 11 to hold the drill rod connector. Hand 24, operate the left handle of winch 5 to wind the wire rope 16, lifting the entire drill string 23 in the hole until the second drill rod connector 24 reaches above the borehole plate 21. Tighten the right handle of winch 5 while simultaneously releasing the left handle, so that the entire drill string 23 is lifted into the air by winch 5. Use a fork to hold the drill rod connector 24, and operate the right handle of winch 5 to lower the entire drill string 23, placing the fork on the borehole plate 21. Use a disassembly tool to hold the drive drill rod 8 connector, manually move the fork, and loosen the threads of the drive drill rod 8 connector, thus separating the connection between the two drill rod connectors 24.The entire drill string 23 below the orifice plate 21 is suspended by a fork. The removed drill rod 22 is lifted and suspended by the winch 5. The right handle of the winch 5 is released to lower the drill string retrieval device 11 and the drill rod 22. One end of the drill rod 22 is lowered by the winch 5, while the other end is manually held and moved to the placement area. The shackle of the drill string retrieval device 11 is released, and the left handle of the winch 5 is used to lift the drill string retrieval device 11 to the position of the orifice plate 21. The drill rod 22 is then secured by the drill string retrieval device 11. The left handle of the winch 5 is then used to lift the drill string retrieval device 11. This process of retrieving the drill rod 22 is repeated until the drill rod 22 and the drill string 23 are removed from the borehole.

[0042] During drill string lifting, to ensure the normal operation of the drilling rig, the drilling rig operator must work closely with the personnel at the borehole to maintain a smooth lifting process and prevent the core from falling out of the core tube 26. When a speed change is required during the extraction of drill string 23, the drum of the winch 5 should be braked first, and then the clutch 3 should be disengaged to engage the gear and change speed.

[0043] S5 Core Sampling: Throughout the drilling process into the topsoil layer, dry drilling is employed within the borehole section. Core samples are retrieved when the drilling reaches the required level. For example... Figure 2 As shown in Figure 5, the carbide drill bit 27, along with the core tube 26, head 25, and drill pipe connector 24, forms a drill string 23, which serves as a core extraction tool. During core extraction, the threads of the mud pump inlet pipe connector are connected to the threads of the drill pipe connector 24 of the drill string 23, and the threads are tightened with pipe wrenches. The mud pump is started, and cooling water is injected into the drill pipe connector 24 of the drill string 23. The cooling water fills the space of the drill string 23, and the water pressure squeezes the soil core in the drill string 23, causing the topsoil core to detach from the core tube 26. This facilitates rapid core extraction while ensuring the integrity of the core and minimizing disturbance. The core recovery rate for the fill layer is no less than 80%, and the core recovery rate for the soil layer is no less than 90%.

[0044] S6 Core Storage: Cores are stored in standard core boxes, and the placement of cores must meet technical quality requirements. Cores are placed parallel in the core boxes, sequentially from left to right and top to bottom, with the cycle number clearly marked. Mechanical damage to the cores and joints in the cores should be distinguished and identified. Cores are marked with a marker and permanent labels and placed at the end of each core advance. The markings include the borehole number, advance number, box number, total number of boxes, borehole top elevation, and location on the engineering structure. Cores are sorted, packed, and numbered sequentially, ensuring no cores are reversed, and core tags are correctly filled out.

[0045] S7 Hydrogeological Observation: Water level measurement is required upon initial groundwater encounter during drilling, and borehole water level observation should be conducted 24 hours after borehole closure. Combined with regional hydrological data, the burial and variation of groundwater at the site should be investigated, and a site hydrogeological condition analysis should be performed. During drilling, water level should be measured once after drilling is lifted and once before drilling resumes, with an interval of no less than 5 minutes between the two measurements. Hydrogeological observations will be conducted using a trading hydrogeological clock. Observation records should be meticulously maintained after each hydrogeological observation.

[0046] To ensure the quality requirements of the borehole, an inclination measurement is performed every 5 meters of drilling, and the borehole inclination must not exceed 3° within every 100 meters. A borehole inclination measurement record is made after each measurement.

[0047] Fill out the drilling record: After the drill string is lifted and the core is placed, carefully fill out the original shift report. The original shift report must be filled out according to regulations, ensuring that the data is complete, accurate, timely, and neat. The shift report must be carefully checked at the end of the shift, and any errors should be corrected promptly. Before the end of the drilling, carefully check the shift report, and after the end of the drilling, return the shift report to the unit for safekeeping.

[0048] S8 Next Drilling Round: Proceed with the next dry drilling round.

[0049] The drilling method for topsoil layers using this geological drilling rig primarily employs a dry drilling approach that combines dry and wet methods. The wet method provides a suitable amount of cooling water to the borehole. This cooling water does not need to be pumped and circulated throughout the entire drilling process; only a suitable amount needs to be injected into the borehole. Once the core tube 26 is filled with cooling water and the drill bit 23 is submerged, the mud pump is shut off, and the injection of cooling water into the borehole ceases. The cooling water only serves to cool and lubricate the drill bit 27. Compared to traditional drilling, this method eliminates the need for a mud pump to extract cooling water for internal borehole circulation during drilling, preventing the cooling water from eroding the topsoil core. This ensures the core remains intact, resulting in a high core recovery rate. Furthermore, the elimination of the need for a mud pump to extract cooling water for internal borehole circulation saves on drilling costs. The vertical shaft lifting and reversing valve handle 19 controls the drilling of the drill rod 22. During the control process, the overflow valve pressure regulating handle 17 continuously applies pressure, causing the vertical shaft 6 to descend and drive the drill bit 23 to cut the soil layer and drill a hole. For well-cohesive soil layers, backfill soil layers, and stable gravel layers, a combination of dry and wet drilling techniques can be used. Using dry drilling allows operators to control the drilling rig according to the specific site conditions, ensuring smooth drilling, offering excellent operability and safety, while also improving drilling efficiency.

[0050] This geological drilling method for drilling into topsoil layers reduces the risk of drill bit jamming or stalling due to manual operation. The use of dry drilling eliminates the need for the mud pump to continuously circulate cooling water within the borehole, thus saving on drilling costs.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for drilling topsoil layers using a geological drilling rig, characterized in that: The geological drilling rig uses a dry drilling method that combines dry and wet methods in the rotary drilling construction of the geological drilling rig to drill into the topsoil layer. Includes the following steps: S1. Preparations before starting the drilling rig; S2. Start the power unit (1), engage the clutch, and place the transfer case handle in the winch position to enable the winch to work. Use the winch to lower the drill bit first, then the drill rod, to prepare to start drilling. S3. Before drilling, cooling water is supplied through a high-pressure hose of a mud pump. The cooling water flows from the drill bit into the borehole, filling the core tube and submerging the drill string. The cooling water does not need to be pumped out and circulated throughout the drilling process. Only a suitable amount of cooling water needs to be injected into the borehole. When the cooling water fills the core tube and submerges the drill string, the mud pump is turned off, and the injection of cooling water into the borehole is stopped. The cooling water only needs to cool and lubricate the drill bit. During the drilling process, the mud pump does not need to pump out cooling water for internal circulation within the borehole. The rotary head drives the active drill rod, which in turn drives the drill rod and drill string in the hole to rotate, enabling the drill bit to quickly cut into the soil layer and perform dry drilling. S4. When the drilling tool has been working for a period of time and the drilling length is close to the core tube length, or the drilling tool is ready to be pulled out, the drilling tool needs to be pulled out and the core is taken out of the core tube. Pulling out the drilling tool requires taking out all the drill rods and drilling tools out of the borehole in sequence. S5. Core extraction is performed using a core sampling tool. During core extraction, the mud pump inlet is connected to the drill pipe connector of the drill bit. Cooling water is injected through the mud pump to fill the drill bit space. The water pressure is used to squeeze the soil core in the drill bit, causing the topsoil core to detach from the core tube. The core sampling tool in step S5 is a carbide drill bit with a core tube, head, and drill pipe connector. During core extraction in step S5, the core recovery rate of the backfill layer is not less than 80%, and the core recovery rate of the soil layer is not less than 90%. S6. Core samples taken from the core tube are placed parallel to each other in the core box, and the number of cycles is clearly marked. The core samples are clearly marked, including the borehole number, cycle number, box number, total number of boxes, borehole top elevation, and location on the engineering structure. The core samples are sorted, packed, and numbered in sequence. S7. When groundwater is first encountered in all boreholes, the water level is measured. Combined with regional hydrological data, the burial status and variation range of groundwater at the site are investigated, and the hydrogeological conditions of the site are analyzed. S8. Proceed to the next dry drilling operation; during drilling operations, each cycle from drilling down to core extraction is called a cycle.

2. The method for drilling topsoil layers using a geological drilling rig according to claim 1, characterized in that: The preparatory work before starting the drilling rig in step S1 includes: checking the oil and diesel quantity of the drilling rig's diesel power unit (1), the lubricating oil quantity of the gearbox, and checking that all connecting parts are securely installed; during drilling rig commissioning, all rotating parts operate normally, and the switch starts flexibly and reliably.

3. The method for drilling topsoil layers using a geological drilling rig according to claim 1, characterized in that: The process of operating the drill string using a winch in step S2 is as follows: When the winch lifts the drill string, release the brake and tighten the release brake; when lowering the drill string, release the lifting brake and partially or completely release the brake; when braking the drill string, release the lifting brake and operate the brake handle to gradually brake the drum; finally, tighten the connection between the drill rod connector and the active drill rod connector of the entire drill string set, lock the mechanical chuck, and prepare to start drilling.

4. The method for drilling topsoil layers using a geological drilling rig according to claim 1, characterized in that: In step S3, the high-pressure hose of the mud pump is connected to a water tap to supply cooling water, which can cool the drilling tools and lubricate them.

5. The method for drilling topsoil layers using a geological drilling rig according to claim 1, characterized in that: In step S3, when it is necessary to change the drilling speed during dry drilling, the clutch must be disengaged first to stop the drill bit from rotating, then the corresponding speed gear is adjusted through the gearbox, and finally the clutch is engaged to continue drilling.

6. The method for drilling topsoil layers using a geological drilling rig according to claim 1, characterized in that: In step S7, the water level of all boreholes is measured when groundwater is first encountered, and the borehole water level is observed 24 hours after the borehole is closed.

7. The method for drilling topsoil layers using a geological drilling rig according to claim 1, characterized in that: In order to ensure the quality requirements of the drilling process, the drilling rig performs inclination measurement every 5m during the drilling process, and the borehole inclination must not exceed 3m within every 100m. º .

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