A drilling and sampling device and method for large high-fill site investigation

Abstract

The application discloses a drilling and sampling device and method for large high-filled site investigation. The sampling device comprises a drill rod joint, a double-layer drilling fluid return joint, a double-layer coring pipe and a drill bit which are sequentially connected. A drill rod interface, a liquid distribution chamber, a jet channel and a negative suction chamber which are mutually connected are sequentially arranged in the drill rod joint from top to bottom. The double-layer coring pipe comprises an outer core pipe and an inner core pipe. The double-layer drilling fluid return joint comprises an outer sleeve connected with the outer shell of the drill rod joint, a support seat fixed at the lower end of the outer sleeve, an inner sleeve connected with the support seat and a hollow connecting rod arranged in the inner sleeve. The application realizes the functions of consistent drilling fluid flow direction with sample entering direction of the core pipe, small sample disturbance caused by the drilling fluid, relative static state of the core pipe and the sample, sample not easy to fall off when the drill is pulled out and portable sample withdrawing operation in the core pipe, so as to reduce sample disturbance and improve coring rate when sampling in deep filled soil layer.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering investigation technology, and in particular to a drilling and sampling device and sampling method for large-scale high-fill site investigation. Background Technology

[0002] In geotechnical engineering exploration, drilling with positive circulation of drilling fluid and sampling with single-layer straight-tube sampling drills are commonly used. This method is most suitable for cohesive soil layers and less weathered rock layers. It has a high core recovery rate and minimal sample disturbance, which helps technicians to accurately identify the strata. The sample test data is consistent with the actual strata conditions. However, in sandy soil layers, gravelly soil layers, and strongly weathered rock layers, the core recovery rate of this method will decrease significantly and the disturbance will increase. Even worse, in plain fill and miscellaneous fill layers with poor backfilling technology and poor soil quality, due to the common problems of underconsolidation, poor soil density, and poor cohesion, when using positive circulation drilling with a single-layer straight tube drill for sampling, most of the soil entering the core tube is dispersed by the drilling fluid during the drilling process and circulated to the surface with the drilling fluid. The few soil samples that remain in the core tube will fall off during the drilling process, resulting in an extremely low core recovery rate when drilling in fill layers. In addition, the drilling fluid flushing inside the core tube, as well as the hammering or water pressure removal of the sample after drilling, seriously damages the integrity of the sample and causes significant soil disturbance. Especially in high embankment areas, the deep fill layer reduces the quality of sampling, making it difficult to distinguish the composition of the sample and accurately determine its location in the strata. This seriously affects the evaluation of the engineering characteristics of the fill layer by technical personnel, thus leaving hidden dangers for the construction of projects in high embankment areas and even causing serious economic losses to the owners. Summary of the Invention

[0003] To address the problems existing in the above-mentioned background technology, this invention proposes a drilling sampling device and sampling method for large-scale high-fill site exploration. The sampling device can achieve the following functions: the drilling fluid flow direction is consistent with the direction of sample entering the core tube; the drilling fluid causes little disturbance to the sample; the core tube and the sample are relatively stationary; the sample is not easy to fall off when the core tube is full and the sample removal operation inside the core tube is portable. In this way, the device can reduce sample disturbance and improve the core recovery rate when sampling deep fill layers.

[0004] To achieve the above-mentioned technical objectives, the present invention provides a drilling and sampling device for large-scale high-fill site exploration. The drilling and sampling device includes a drill pipe joint, a double-layer drilling fluid return joint, a double-layer core tube, and a drill bit connected in sequence. The drill pipe joint is provided with a drill pipe interface, a fluid distribution chamber, a jet channel, and a negative suction chamber connected in sequence from top to bottom. Multiple jet channels are provided and distributed at the bottom of the fluid distribution chamber. Each jet channel connects the fluid distribution chamber and the negative suction chamber, and the aperture of each jet channel gradually decreases from the fluid distribution chamber to the negative suction chamber.

[0005] The double-layer core tube includes an outer core tube and an inner core tube, with a return fluid cavity formed between the outer core tube and the inner core tube. The drill bit is installed at the end of the outer core tube, and multiple first return fluid ports leading to the return fluid cavity are opened at the position of the drill bit near the end of the inner core tube.

[0006] The double-layer drilling fluid return connector includes an outer casing connected to the drill pipe connector housing, a support base fixed to the lower end of the outer casing, an inner casing connected to the support base, and a hollow connecting rod placed inside the inner casing. The lower end of the outer casing is connected to the outer core tube. A blowout chamber communicating with the negative suction chamber is provided between the inner and outer casings, and multiple fluid outlets are opened in the lower part of the outer casing wall. The hollow connecting rod is rotatably connected to the inner casing through a bearing assembly, and the upper end of the hollow connecting rod is rotatably connected to the bottom of the drill pipe connector. The lower end extends out of the support base and is fixedly connected to the inner core tube of the double-layer coring tube. The upper part of the connecting rod cavity inside the hollow connecting rod communicates with the negative suction chamber, and the lower part communicates with the return fluid chamber.

[0007] A further technical solution of the present invention: The inner core tube is provided with a core sample clamping mechanism, which includes at least two clamping plates disposed at the port of the inner core tube, a limiting ring sleeved outside the clamping plates, and a baffle placed in the inner cavity of the inner core tube. The middle part of each clamping plate is rotatably installed at the port of the inner core tube via a rotating shaft, and the part of the clamping plate above the rotating shaft is connected to the inner core tube by a spring. The limiting ring is sleeved at the connection between the clamping plate and the inner core tube. A baffle sliding cavity is provided at the upper part of the inner core tube. The baffle is slidably placed in the sliding cavity and is connected to the limiting ring by a connecting rope extending from the inner core tube. When the baffle moves up along the baffle sliding cavity to the top surface of the inner core tube under the push of the core sample, the limiting ring disengages from the clamping plate, and the handle end of the clamping plate opens under the action of the spring, clamping the core sample tightly.

[0008] The preferred technical solution of the present invention is that the jet channel is distributed in a ring on the bottom surface of the liquid separation chamber and is inclined outward from the liquid separation chamber to the negative suction chamber.

[0009] The preferred technical solution of the present invention is as follows: the part of the hollow connecting rod that extends into the outer core tube is provided with a flared threaded interface and is threadedly connected to the inner core tube. Multiple second return ports are provided in the part of the hollow connecting rod located between the outer core tube and the inner core tube. The multiple second return ports are distributed in a ring on the hollow connecting rod, and the return cavity is connected to the connecting rod cavity through the second return ports.

[0010] The preferred technical solution of the present invention is as follows: the upper end of the outer casing is threadedly connected to the outer wall of the drill pipe joint, the lower end is threadedly connected to the upper end of the outer core tube, the drill bit is threadedly connected to the lower end of the outer core tube, and the first return fluid port is distributed in a ring on the edge of the inner ring of the drill bit to form a gear-shaped return fluid port.

[0011] The preferred technical solution of the present invention is as follows: the bearing assembly includes a first bearing, a nut, and a second bearing. The nut is fixedly sleeved on the middle part of the hollow connecting rod. The first bearing and the second bearing are respectively disposed at both ends of the nut and fixed on the hollow connecting rod. A washer is provided between each bearing and the nut. The inner sleeve is rotatably sleeved on the outside of the bearing assembly.

[0012] The preferred technical solution of the present invention is as follows: the inner core tube is a semi-closed inner tube, and a through hole communicating with the return fluid cavity is opened on its top surface. The through hole is inclined upward from the inner cavity of the inner core tube toward the return fluid cavity; the number of clamping pieces is even, symmetrically distributed at the bottom of the two halves of the inner core tube, each clamping piece is an arc-shaped clamping piece, and its clamping surface is provided with a leather layer. At least two clamping pieces are combined to form a cylindrical structure that matches the inner core tube.

[0013] The preferred technical solution of the present invention is as follows: the diameter of the baffle sliding cavity is smaller than the diameter of the inner core tube; a perforation is provided on the inner core tube wall at the lower part of the baffle sliding cavity; multiple rope guide holes are provided on the outer wall of the inner core tube; the connecting rope extends out of the inner core tube through the perforation and extends along the rope guide holes to the lower part of the inner core tube to connect with the limiting ring; multiple air and water permeable holes are provided on the baffle.

[0014] To achieve the above-mentioned technical objectives, the present invention also provides a drilling and sampling method for large-scale high-fill site exploration, characterized in that: the sampling method uses the aforementioned drilling and sampling device for large-scale high-fill site exploration for sampling, and the specific steps are as follows:

[0015] (1) After the drilling location is marked on site, the drilling rig is moved to the borehole opening for positioning. The vertical correction of the drilling rig and the placement of equipment are completed, and drilling fluid is prepared to complete the preparatory work.

[0016] (2) After the drilling and sampling device for large high embankment site survey is assembled, it is connected to the active drill rod of the drilling machine through the drill rod joint for drilling and sampling.

[0017] (3) During the drilling process, drilling fluid is pumped into the active drill pipe and the drilling sampling device by the mud pump. The drilling fluid flows into the distribution chamber of the drill pipe joint through the active drill pipe, and then enters the negative suction chamber through multiple jet channels. It flows through the outlet at the bottom of the jet chamber to the annular gap between the borehole wall and the outer tube of the drilling sampling device. The drilling fluid flows down along the gap to the outside of the drill bit, and flows into the return fluid chamber between the outer core tube and the inner core tube through the first return fluid port arranged in gears at the bottom of the drill bit. It then flows up along the return fluid chamber to the connecting rod cavity of the hollow connecting rod. The drilling fluid entering the connecting rod cavity is sucked into the negative suction chamber, and then flows from the negative suction chamber through the jet chamber to the annular gap between the borehole wall and the outer tube of the drilling sampling device to carry out the drilling fluid circulation process.

[0018] (4) When the sample in the inner core tube is placed in the position of the baffle, push the baffle to move upward in the sliding cavity. During the movement of the baffle, the limiting ring moves upward and disengages from the clamping plate. The clamping plate clamps the sample under the action of the spring. Turn off the mud pump to stop the drilling fluid circulation. Use the drilling rig winch to lift the drill and complete the drilling sampling process.

[0019] A further technical solution of the present invention: The inner core tube is a core tube composed of two half tubes joined together. After the drill is lifted in step (4), the outer core tube is first unscrewed from the sampling drill tool and the exposed inner core tube is removed. Then the inner tube is unscrewed from the connecting rod and removed. After the limiting ring is removed, the two half tubes of the inner core tube can be separated, and the sample is taken out and placed from the half tube.

[0020] In this invention, the drilling fluid circulation path inside the sampling drill bit is as follows: it flows downward from the drill pipe joint of the sampling drill bit into the sampling device's distribution chamber, jet channel, negative suction chamber, and spray chamber; it flows out through the outer pipe nozzle to the gap between the borehole wall and the outer pipe annulus; it flows downward along this gap to the outside of the drill bit; it flows through the bottom of the borehole and the gear-shaped nozzle inside the drill bit to the gap between the inner and outer pipe annulus; it flows upward along this gap to the connecting rod nozzle; it enters the connecting rod cavity and is then sucked upward into the negative suction chamber; from the negative suction chamber, it flows through the spray chamber to the gap between the borehole wall and the outer pipe annulus; thus, the drilling fluid at the bottom of the borehole mainly flows downward through the borehole wall and the outer pipe annulus, and upward through the gap between the inner and outer pipe annulus, avoiding the sample in the inner pipe being scoured by the drilling fluid and disturbed by the fluid.

[0021] The present invention employs multiple jet channels with progressively smaller diameters. This increases the flow velocity of the drilling fluid from the distribution chamber to the negative suction chamber, creating a high-speed fluid. The jet principle is achieved through these jet channels.

[0022] A low-pressure zone forms near high-speed fluid, causing the surrounding normal-pressure zone liquid to flow towards the low-pressure area. In this invention, the connecting rod cavity is the normal-pressure zone, and the drilling fluid returning through the connecting rod cavity is drawn upward by the negative suction chamber.

[0023] A circulation is formed. The present invention has a jet chamber below the negative suction chamber, which can decelerate the high-speed fluid. The reduced-speed drilling fluid flows into the gap between the borehole wall and the outer pipe through the outlet, ensuring that the drilling fluid entering the gap between the borehole wall and the outer pipe is at a low speed and will not scour the borehole wall.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) In this invention, the drilling fluid is partially reverse-circulated within the sampling drill bit range at the bottom of the hole, and then flows upward along the gap between the hole wall to the mud pit at the top of the hole. At the bottom of the hole, the drilling fluid mainly flows downward between the hole wall and the outer annulus space, and flows upward between the inner and outer annulus spaces. In this invention, the drilling fluid flows in the same direction as the sample enters the core tube at the bottom of the hole, and the drilling fluid mostly flows in the gap between the inner and outer annulus spaces. Less drilling fluid flows into the core tube, which reduces the hydraulic disturbance of the drilling fluid to the sample.

[0026] (2) After the sample fills the inner tube, the baffle is pushed upward and the limiting ring moves upward until it separates from the clamping plate. Under the action of the spring, the upper end of the clamping plate rotates outward and the lower end rotates inward, and the bottom of the sample is clamped. At the same time, the inner surface of the clamping plate is provided with a leather layer. The leather increases the friction between the sample and the sample, further preventing the sample from falling off and ensuring that the sample is fixed in the inner tube and does not easily fall off during the drilling process.

[0027] (3) The present invention achieves dual-tube single-action through bearing assembly. The drill rod drives the outer core tube and drill bit of the sampling device to rotate and drill. The inner core tube and the sample entering it remain relatively stationary, avoiding sample disturbance caused by the relative movement of the sample and the core tube.

[0028] (4) The inner core tube of the present invention is set as a semi-closed inner tube, which avoids the secondary disturbance to the sample caused by traditional hammering or water pressure to remove the sample. The inner tube is directly split into two halves, which makes it easier to remove the sample from the inner tube with less disturbance. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the exploration and sampling device of the present invention;

[0030] Figure 2 for Figure 1 Sectional view of AA in the middle;

[0031] Figure 3 for Figure 1 Cross-sectional view of the middle section (BB);

[0032] Figure 4 for Figure 1 CC section view;

[0033] Figure 5 for Figure 1 Enlarged schematic diagram of the drill bit section;

[0034] Figure 6 for Figure 1 Enlarged schematic diagram of section D in the middle;

[0035] Figure 7 This is a schematic diagram of drilling fluid circulation in this invention;

[0036] Figure 8This is an overall schematic diagram of the clamping state of the clamping piece in this invention;

[0037] Figure 9 This is an enlarged schematic diagram of the drill bit portion in the clamping state of the clamping plate in this invention;

[0038] Figure 10 A cross-sectional view of the second return port portion of the hollow connecting rod of the present invention.

[0039] In the diagram: 1—Drill pipe joint, 2—Inner casing, 3—Outer casing, 4—Connecting rod cavity, 5—Hollow connecting rod, 6—Outer core tube, 7—Inner core tube, 8—Drill bit, 9—Drill pipe interface, 10—Distribution chamber, 11—Jet channel, 12—Negative suction chamber, 13—First bearing, 14—Nut, 15—Washer, 16—Spray chamber, 17—Second bearing, 18—Outlet, 19—Support base, 20—Second return port, 21—Through hole, 22—Baffle, 23—Connecting rope, 24—Rope guide hole, 25—Limiting shackle, 26—Spring, 28—Clamping piece, 29—Leather layer, 30—Return chamber, 31—First return port, 32—Sliding chamber. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments. Figures 1 to 10 All accompanying drawings are simplified versions of embodiments and are intended only to clearly and concisely illustrate the embodiments of the present invention. The technical solutions shown in the drawings below are specific solutions of embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0042] The drilling and sampling device for large-scale high-fill site exploration provided in Example 1, such as Figures 1 to 6As shown, the drilling sampling device includes a drill pipe joint 1, a double-layer drilling fluid return joint, a double-layer core tube, and a drill bit 8 connected in sequence. The drill pipe joint 1 is provided with a drill pipe interface 9, a fluid distribution chamber 10, a jet channel 11, and a negative suction chamber 12 connected to each other from top to bottom. There are multiple jet channels 11, which are distributed in a ring on the bottom surface of the fluid distribution chamber 10. Each jet channel 11 connects the fluid distribution chamber 10 and the negative suction chamber 12, and is inclined outward from the fluid distribution chamber 1 to the negative suction chamber. The aperture of each jet channel 11 gradually decreases from the fluid distribution chamber 10 to the negative suction chamber 12. The double-layer core tube includes an outer core tube 6 and an inner core tube 7. A return fluid cavity 30 is formed between the outer core tube 6 and the inner core tube 7. The drill bit 8 is threaded to the end of the outer core tube 6, and multiple first return fluid ports 31 leading to the return fluid cavity 30 are opened at the position of the drill bit 8 near the end of the inner core tube 7. The first return fluid ports 31 are distributed in a ring on the inner ring edge of the drill bit 8 to form a gear-shaped return fluid port.

[0043] The drilling and sampling device for large-scale high-fill site exploration provided in Example 1, such as Figures 1 to 6 As shown, the double-layer drilling fluid return connector includes an outer casing 3 threadedly connected to the outer shell of the drill pipe connector 1, a support base 19 fixed to the lower end of the outer casing 3, an inner casing 2 connected to the support base 19, and a hollow connecting rod 5 placed inside the inner casing 2. The lower end of the outer casing 3 is threadedly connected to the outer core tube 6. A blowout chamber 16 communicating with the negative suction chamber 12 is provided between the inner casing 2 and the outer casing 3, and multiple fluid outlets 18 are opened at the lower part of the outer casing 3, such as... Figure 10 As shown, multiple liquid outlets 18 are arranged in a ring on the wall of the hollow connecting rod 5. The hollow connecting rod 5 is rotatably connected to the inner sleeve 2 via a bearing assembly. The upper end of the hollow connecting rod 5 is rotatably connected to the bottom of the drill pipe joint 1, and the lower end extends out of the support base 19 and is fixedly connected to the inner core tube 7 of the double-layer coring tube. The upper part of the connecting rod cavity 4 inside the hollow connecting rod 5 is connected to the negative suction chamber 12, and the lower part is connected to the return liquid chamber 30. The part of the hollow connecting rod 5 that extends into the outer core tube 6 is provided with a flared threaded interface and is threadedly connected to the inner core tube 7. Multiple second return liquid ports 20 are opened in the part of the hollow connecting rod 5 located between the outer core tube 6 and the inner core tube 7. The multiple second return liquid ports 20 are arranged in a ring on the hollow connecting rod 5, and the return liquid chamber 30 is connected to the connecting rod cavity 4 through the second return liquid ports 20. The bearing assembly includes a first bearing 13, a nut 14, and a second bearing 17. The nut 14 is fixedly sleeved on the middle part of the hollow connecting rod 5. The first bearing 13 and the second bearing 17 are respectively disposed at both ends of the nut 14 and fixed on the hollow connecting rod 5. A washer 15 is provided between each bearing and the nut 14. The inner sleeve 2 is rotatably sleeved on the outside of the bearing assembly.

[0044] The method of local reverse circulation of drilling fluid at the bottom of the well in this invention is as follows: Figure 7As shown, drilling fluid flows from the drill pipe into the upper liquid distribution chamber 10 of the sampling device, and then flows at high speed into the jet chamber 16 through the liquid distribution channel 11. The high-speed fluid passes through the negative suction chamber 12, which generates negative pressure. The drilling fluid flows out from the outlet hole 18 on the outer tube side wall of the jet chamber 16 and flows to the bottom of the hole at the drill bit 8 under its own weight. The drilling fluid enters the return chamber 30 between the inner core tube 7 and the outer core tube 6 through the first return port 31 at the bottom of the drill bit 8, and then flows upward into the inner cavity 4 of the connecting rod. The inner cavity 4 of the connecting rod is connected to the negative suction chamber 12. Under the action of negative pressure, the drilling fluid is sucked into the negative suction chamber 12, and then flows into the pressure chamber 16 and finally flows out, forming a local reverse circulation of drilling fluid around the sampling device.

[0045] In this invention, the double-layer drilling fluid return connector consists of an inner casing 2 and an outer casing 3. The double-layer coring tube includes an outer core tube 6 and an inner core tube 7. A hollow connecting rod 5 is provided inside the inner casing 2, and the hollow connecting rod 5 is fixedly connected to the inner core tube 7. The outer core tube 6 is threadedly connected to the outer casing 3. A bearing assembly is provided between the inner core tube 7 and the hollow connecting rod 5. The bearing assembly enables the double tubes to move independently. The drill pipe drives the outer core tube 6 and the drill bit 8 of the sampling device to rotate and drill. The inner core tube 7 and the sample inside it remain relatively stationary to avoid sample disturbance caused by relative movement between the sample and the coring tube. After the drilling is completed and the drill string is pulled up, the outer core tube 6 and the inner core tube 7 are unscrewed in sequence. The inner tube, which is a semi-closed tube, can be opened by first axially shifting and then radially separating. The sample can be easily taken out from the semi-closed tube, avoiding secondary disturbance to the sample caused by conventional hammering or water pressure. The sample is then loaded into the sampler or placed in the sample box as required, and the drill string is lowered again for the next drilling step.

[0046] The drilling and sampling device for large-scale high-fill site exploration provided in Example 1, such as Figure 1 , Figures 5 to 9As shown, the inner core tube 7 is provided with a core sample clamping mechanism. The core sample clamping mechanism includes at least two clamping pieces 28 disposed at the port of the inner core tube 7, a limiting ring 25 sleeved outside the clamping pieces 28, and a baffle 22 placed in the inner cavity of the inner core tube 7. The inner core tube 7 is a semi-closed inner tube with a through hole 21 on its top surface that communicates with the return fluid chamber 30. The through hole 21 is inclined upward from the inner cavity of the inner core tube 7 toward the return fluid chamber 30. The circulating drilling fluid in the return fluid chamber 30 also flows upward, preventing the liquid in the return fluid chamber 30 from entering the inner core tube 7. The number of clamping pieces 28 is even, and they are symmetrically distributed at the bottom of the two halves of the inner core tube 7. The middle part of each clamping piece 28 is rotatably mounted on the port of the inner core tube 7 via a rotating shaft 27, and the part of the clamping piece 28 above the rotating shaft is connected to the inner core tube 7 by a spring 26. Each clamping piece 28 is an arc-shaped clamping piece, and its clamping surface is provided with a leather layer 29. At least two clamping pieces 28 are combined to form a cylindrical structure that matches the inner core tube 7. The limiting ring 25 is sleeved on the connection between the clamping piece 28 and the inner core tube 7; a baffle sliding cavity 32 is provided on the upper part of the inner core tube 7, the baffle 22 is slidably placed in the sliding cavity 32, and is connected to the limiting ring 25 by the connecting rope 23 extending out of the inner core tube 7, and when the baffle 22 moves up along the baffle sliding cavity 32 to the top surface of the inner core tube 7 under the push of the core sample, the limiting ring 25 disengages from the clamping piece 28, and the handle end of the clamping piece 28 opens under the action of the spring 26, and the clamping end clamps the core sample. The diameter of the baffle sliding cavity 32 is smaller than the diameter of the inner core tube 7. A perforation is provided on the inner core tube wall at the lower part of the baffle sliding cavity 32. Multiple rope guide holes 24 are provided on the outer wall of the inner core tube 7. The connecting rope 23 extends out of the inner core tube 7 through the perforation and extends along the rope guide hole 24 to the lower part of the inner core tube 7 to connect with the limiting ring 25. Multiple air and water permeable holes are provided on the baffle 22.

[0047] The inner core tube 7 of this invention is provided with a clamping mechanism, which is controlled by a baffle 22 disposed inside the inner core tube 7. The baffle 22 can move within the sliding cavity 32 at the upper part of the inner core tube 7. The baffle 22 is connected to a limiting ring 25 outside the inner core tube 7 via a rope limited in the rope guide hole 24. The limiting ring 25 is sleeved on the upper end of the clamping piece 28 and contains a compressed spring 26. The clamping piece 28 is connected to the inner core tube 7 by a pivot at its middle end, and leather is embedded inside the lower end of the clamping piece 28. Figure 8 and Figure 9 As shown, after the sample fills the core tube, the baffle 22 moves upward, causing the limiting ring 25 to move upward and loosen from the clamping plate 28. The action of the spring 26 causes the clamping plate 28 to move outward from the upper end and inward from the lower end around the rotating shaft. The inner diameter shrinks and clamps the sample. The leather layer 29 on the inner side of the clamping plate 28 further increases the friction force on the contact surface with the sample, thereby preventing the sample from falling off during the drilling process.

[0048] The drilling fluid circulation method of this invention is full-hole positive circulation + bottom-hole local reverse circulation. The circulation path is as follows: the mud is drawn into the drill pipe from the mud pit by the mud pump, flows downward from the drill pipe into the sampling device's distribution chamber 10, jet channel 11, negative suction chamber 12 and blown-in chamber 16, flows out through the outlet 18 to the outer annular space of the borehole wall, flows downward along this gap to the outside of the drill bit 8, flows through the bottom of the borehole and the first return port 31 on the inside of the drill bit 8 to the return chamber 30, flows upward along the return chamber 30 to the position of the second return port 20 at the lower part of the hollow connecting rod 5, enters the connecting rod cavity 4, and is then drawn upward to the negative suction chamber 12. From the negative suction chamber 12, it flows through the blown-in chamber 16 to the outer annular space of the borehole wall, flows upward along the gap of the borehole wall and out of the borehole to the mud pit. Drilling fluid enters the borehole from the drill pipe downwards and flows upwards through the gap between the drill pipe and the borehole wall, ensuring that the borehole sidewall does not collapse due to the drilling fluid flowing downwards. At the bottom of the borehole, the drilling fluid enters the return fluid chamber 30 from the outside of the drill bit and flows upwards into the inner cavity 4 of the connecting rod and the negative suction chamber 12. The direction of the drilling fluid flow is consistent with the direction of the sample entering the core tube, avoiding contact between the sample and the drilling fluid, which would cause the sample to be scattered and severely disturbed.

[0049] Example 2 is a series of detailed site surveys for a capacity replacement and upgrading project. The project site is a mountainous backfill area, including both fill and excavation areas. The site contains multiple elevation platforms. The fill thickness in the fill areas is mostly 10-30m, with some high fill areas reaching 40-50m. To accurately determine the geological distribution and improve drilling efficiency in the fill areas, the large-scale high fill site survey drilling and sampling device from Example 1 was used for survey drilling and sampling during the detailed survey fieldwork. The specific steps are as follows:

[0050] (1) During the exploration operation, after the borehole design is determined and the borehole is laid out according to the borehole coordinates, the drilling rig is moved to the borehole opening for positioning, the vertical correction of the drilling rig and the placement of equipment are completed, and drilling fluid is prepared to complete the preparatory work.

[0051] (2) After assembling the drilling and sampling device for large high embankment site survey, the double-layer core tube is selected with a large diameter short rod and connected to the active drill rod of the drilling machine through the drill rod joint for drilling and sampling.

[0052] (3) During the drilling process, drilling fluid is pumped into the active drill pipe and the drilling sampling device by the mud pump. The drilling fluid flows into the distribution chamber of the drill pipe joint through the active drill pipe, and then enters the negative suction chamber through multiple jet channels. It flows through the outlet at the bottom of the jet chamber to the annular gap between the borehole wall and the outer tube of the drilling sampling device. The drilling fluid flows down along the gap to the outside of the drill bit, and flows into the return fluid chamber between the outer core tube and the inner core tube through the first return fluid port arranged in gears at the bottom of the drill bit. It then flows up along the return fluid chamber to the connecting rod cavity of the hollow connecting rod. The drilling fluid entering the connecting rod cavity is sucked into the negative suction chamber, and then flows from the negative suction chamber through the jet chamber to the annular gap between the borehole wall and the outer tube of the drilling sampling device to carry out the drilling fluid circulation process.

[0053] (4) When the sample in the inner core tube is placed in the position of the baffle, push the baffle to move upward in the sliding cavity. During the movement of the baffle, the limiting ring moves upward and disengages from the clamping plate. The clamping plate clamps the sample under the action of the spring. Turn off the mud pump to stop the drilling fluid circulation. Use the drilling rig winch to lift the drill and complete the drilling sampling process.

[0054] (5) After the drill is lifted in step (4), first unscrew the outer core tube from the sampling drill bit and remove the exposed inner core tube. Then unscrew the inner core tube 7 from the connecting rod. After the limiting clasp is removed, the two halves of the inner core tube can be separated. Take out the sample from the half tube and place it.

[0055] (6) Replace the sampling drill bit with a double-layer core tube with a thinner diameter long rod, connect the drill rod and then connect the active drill rod; repeat the above steps, drill down, lift the drill, take samples, connect the drill rod and gradually drill down to penetrate the backfill layer until the designed hole depth; disassemble the drill rod and drill bit and store them in the drilling machine, and move the drilling machine to the subsequent hole for drilling and sampling.

[0056] After sampling was completed and the drilling rig was moved, on-site technicians cataloged and delineated the fill layers based on the soil cores retrieved during drilling. The application of this sampling tool significantly reduced soil core disturbance, resulting in more complete samples and a marked improvement in the accuracy of fill layer delineation. Furthermore, the samples were marked according to borehole number and sampling depth, then collected and promptly sent to the geotechnical laboratory for geotechnical testing. Because the fill layers were obtained as undisturbed, the tests provided a solid basis for obtaining relevant parameters, including fill layer cohesion, internal friction angle, side friction resistance, and bearing capacity characteristic values.

[0057] The above description is merely one embodiment of the present invention, and while it is detailed and specific, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A drilling and sampling device for large-scale high-fill site exploration, characterized in that: The drilling sampling device includes a drill pipe joint (1), a double-layer drilling fluid return joint, a double-layer core tube and a drill bit (8) connected in sequence. The drill pipe joint (1) is provided with a drill pipe interface (9), a liquid distribution chamber (10), a jet channel (11) and a negative suction chamber (12) connected in sequence from top to bottom. There are multiple jet channels (11) distributed at the bottom of the liquid distribution chamber (10). Each jet channel (11) is connected to the liquid distribution chamber (10) and the negative suction chamber (12). The diameter of each jet channel (11) gradually decreases from the liquid distribution chamber (10) to the negative suction chamber (12). The double-layer core tube includes an outer core tube (6) and an inner core tube (7). A return fluid cavity (30) is formed between the outer core tube (6) and the inner core tube (7). The drill bit (8) is installed at the end of the outer core tube (6), and multiple first return fluid ports (31) leading to the return fluid cavity (30) are opened at the position of the drill bit (8) near the end of the inner core tube (7). The double-layer drilling fluid return joint includes an outer casing (3) connected to the outer shell of the drill pipe joint (1), a support base (19) fixed to the lower end of the outer casing (3), an inner casing (2) connected to the support base (19), and a hollow connecting rod (5) placed inside the inner casing (2). The lower end of the outer casing (3) is connected to the outer core tube (6). A blowout chamber (16) communicating with the negative suction chamber (12) is provided between the inner casing (2) and the outer casing (3). ), and multiple liquid outlets (18) are provided at the lower part of the outer sleeve (3); the hollow connecting rod (5) and the inner sleeve (2) are rotatably connected by a bearing assembly, and the upper end of the hollow connecting rod (5) is rotatably connected to the bottom of the drill pipe joint (1), and the lower end extends out of the support base (19) and is fixedly connected to the inner core tube (7) of the double-layer core tube. The upper part of the connecting rod cavity (4) in the hollow connecting rod (5) is connected to the negative suction chamber (12), and the lower part is connected to the return liquid chamber (30); The inner core tube (7) is provided with a core sample clamping mechanism, which includes at least two clamping pieces (28) disposed at the port of the inner core tube (7), a limiting ring (25) sleeved on the clamping pieces (28), and a baffle (22) placed in the inner cavity of the inner core tube (7). The middle part of each clamping piece (28) is rotatably mounted on the port of the inner core tube (7) via a rotating shaft (27), and the part of the clamping piece (28) above the rotating shaft is connected to the inner core tube (7) by a spring (26). The limiting ring (25) is sleeved on the clamping piece (28). 8) Connection with the inner core tube (7); A baffle sliding cavity (32) is provided on the upper part of the inner core tube (7). The baffle (22) is slidably placed in the baffle sliding cavity (32) and connected to the limiting ring (25) by the connecting rope (23) extending out of the inner core tube (7). When the baffle (22) moves up along the baffle sliding cavity (32) to the top surface of the inner core tube (7) under the push of the core sample, the limiting ring (25) disengages from the clamping piece (28). The handle end of the clamping piece (28) opens under the action of the spring (26) and the clamping end clamps the core sample. Multiple second return ports (20) are provided in the part of the hollow connecting rod (5) between the outer core tube (6) and the inner core tube (7). The multiple second return ports (20) are distributed in a ring on the hollow connecting rod (5). The return cavity (30) is connected to the connecting rod cavity (4) through the second return ports (20). The inner core tube (7) is a semi-closed inner tube. A through hole (21) communicating with the return cavity (30) is provided on its top surface. The through hole (21) is inclined upward from the inner cavity of the inner core tube (7) toward the return cavity (30).

2. The drilling and sampling device for large-scale high-fill site exploration according to claim 1, characterized in that: The jet channel (11) is distributed in a ring on the bottom surface of the liquid separation chamber (10) and is inclined outward from the liquid separation chamber (10) to the negative suction chamber.

3. The drilling and sampling device for large-scale high-fill site exploration according to claim 1, characterized in that: The hollow connecting rod (5) has a flared threaded interface in the part that extends into the outer core tube (6) and is threadedly connected to the inner core tube (7).

4. The drilling and sampling device for large-scale high-fill site exploration according to claim 1, characterized in that: The upper end of the outer sleeve (3) is threadedly connected to the outer shell of the drill pipe connector (1), and the lower end is threadedly connected to the upper end of the outer core tube (6). The drill bit (8) is threadedly connected to the lower end of the outer core tube (6). The first return port (31) is distributed in a ring on the inner ring edge of the drill bit (8) to form a gear-shaped return port.

5. A drilling and sampling device for large-scale high-fill site exploration according to claim 1, characterized in that: The bearing assembly includes a first bearing (13), a nut (14), and a second bearing (17). The nut (14) is fixedly sleeved in the middle of the hollow connecting rod (5). The first bearing (13) and the second bearing (17) are respectively set at both ends of the nut (14) and fixed on the hollow connecting rod (5). A washer (15) is provided between each bearing and the nut (14). The inner sleeve (2) is rotatably sleeved on the outside of the bearing assembly.

6. A drilling and sampling device for large-scale high-fill site exploration according to claim 1, characterized in that: The number of clamping pieces (28) is even, and they are symmetrically distributed at the bottom of the two halves of the inner core tube (7). Each clamping piece (28) is an arc-shaped clamping piece with a leather layer (29) on its clamping surface. At least two clamping pieces (28) are combined to form a cylindrical structure that matches the inner core tube (7).

7. A drilling and sampling device for large-scale high-fill site exploration according to claim 1, characterized in that: The diameter of the baffle sliding cavity (32) is smaller than the diameter of the inner core tube (7). A perforation is provided on the inner core tube wall at the lower part of the baffle sliding cavity (32). Multiple rope guide holes (24) are provided on the outer wall of the inner core tube (7). The connecting rope (23) extends out of the inner core tube (7) through the perforation and extends along the rope guide hole (24) to the lower part of the inner core tube (7) to connect with the limiting ring (25). Multiple air and water permeable holes are provided on the baffle (22).

8. A drilling and sampling method for surveying large-scale high-fill sites, characterized in that: The sampling method uses the drilling and sampling device for large-scale high-fill site exploration as described in claim 1, and the specific steps are as follows: (1) After the drilling location is marked on site, the drilling rig is moved to the borehole opening for positioning. The vertical correction of the drilling rig and the placement of equipment are completed, and drilling fluid is prepared to complete the preparatory work. (2) After the drilling and sampling device for large high embankment site survey is assembled, it is connected to the active drill rod of the drilling machine through the drill rod joint for drilling and sampling. (3) During the drilling process, drilling fluid is pumped into the active drill pipe and the drilling sampling device by the mud pump. The drilling fluid flows into the distribution chamber of the drill pipe joint through the active drill pipe, and then enters the negative suction chamber through multiple jet channels. It flows through the outlet at the bottom of the jet chamber to the annular gap between the borehole wall and the outer tube of the drilling sampling device. The drilling fluid flows down along the gap to the outside of the drill bit, and flows into the return fluid chamber between the outer core tube and the inner core tube through the first return fluid port arranged in gears at the bottom of the drill bit. It then flows up along the return fluid chamber to the connecting rod cavity of the hollow connecting rod. The drilling fluid entering the connecting rod cavity is sucked into the negative suction chamber, and then flows from the negative suction chamber through the jet chamber to the annular gap between the borehole wall and the outer tube of the drilling sampling device to carry out the drilling fluid circulation process. (4) When the sample of the inner core tube is placed in the position of the baffle, push the baffle to move upward in the sliding cavity. During the movement of the baffle, the limiting ring moves upward and disengages from the clamping plate. The clamping plate clamps the sample under the action of the spring. Turn off the mud pump to stop the drilling fluid circulation. Use the drilling rig winch to lift the drill and complete the drilling and sampling process.

9. A drilling and sampling method for large-scale high-fill site exploration according to claim 8, characterized in that: The inner core tube is composed of two half tubes joined together. After the drill is lifted in step (4), the outer core tube is first unscrewed from the sampling drill tool and the exposed inner core tube is removed. Then the inner tube is unscrewed from the connecting rod and removed. After the limiting clasp is removed, the two half tubes of the inner core tube can be separated. The sample is taken out from the half tube and placed.

Images