A kind of expansion stirrer for drilling holes in underwater thick fine sand layer and drilling method using the expansion stirrer

Abstract

The present invention relates to an expander for drilling underwater thick fine sand layer and a drilling method using the expander. The expander includes a pipe body, a drill bit, a cutting and stirring rack and a slurry conveying system. The pipe body includes an outer pipe and an inner pipe. The upper end of the outer pipe is detachably connected to the drill rod. The outer wall of the drill rod and the outer wall of the outer pipe are both provided with spiral blades. The lower part of the outer pipe is fitted with an inner pipe, and the lower end of the inner pipe is detachably connected with a drill bit; the cutting and stirring rack is circumferentially arranged outside the pipe body. The drilling method is as follows: according to the properties and thickness of the fine sand layer within the drilling range, the expansion elevation range and the wall thickness are determined, and then the size of the expander is determined; the expander is used for expansion and stirring, and the slurry flowing out of the expander is solidified after being stirred with the soil body, and the modified fine sand mortar mixture in the borehole is sent to the outside of the hole, and finally a hole is formed. By using the expander and the drilling method of the present invention, a slurry soil solidification layer with a thickness of 5 to 20 cm is formed on the hole wall as a drilling wall protection ring, which provides a guarantee for the self-stabilization of the hole wall.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction, and in particular relates to an expander for drilling holes in an underwater thick powdery sand layer and a drilling method using the expander. Background Art

[0002] The fine sand layer has no bonding strength, and its self-stabilization mainly depends on the embedding and biting between soil particles. Therefore, the wall stability of the underwater fine sand layer drilling hole is poor, which is easy to cause the bottom sediment to exceed the limit, and sometimes become a waste hole. When the fine sand layer is rich in high-pressure water, it is more difficult to make a hole. During the construction of a certain project with equal diameter long piles (pile length of more than 40m), high-pressure water (more than 7m of pressure head) and thick fine sand layer (top plate is about 15m from the ground, thickness 4-6m) were encountered. 10 minutes after the hole was made, the bottom sediment was measured to be more than 3m. Although measures such as adjusting the wall protection mud, changing the hole making method (first high-pressure rotary spraying and then hole making) and changing the construction team (with rich experience in underwater fine sand layer hole making and a lot of engineering practice experience) were taken, the problem of thick sediment was still not solved. After many demonstrations, the steel casing wall protection hole was finally used for success, but it paid an extra economic cost of nearly 10 million yuan.

[0003] When drilling in thick silty sand layers underwater, especially when there is high pressure water, the hole wall is unstable and the quality of drilling is often not guaranteed. Therefore, how to control the stability of the hole wall in such underwater, especially high pressure silty sand layers is the key to drilling. Summary of the invention

[0004] The present invention provides an expander and agitator for drilling holes in thick silt and fine sand layers underwater and a drilling method using the expander and agitator to solve the problem that the hole wall stability is poor and the sediment at the bottom of the hole is easily exceeded when drilling holes in thick silt and fine sand layers underwater. The expander and agitator of the present invention injects slurry into the hole wall and stirs it, so that a slurry solidified layer with a thickness of 5 to 20 cm is formed on the hole wall as a drilling wall protection ring, which provides a guarantee for the self-stabilization of the hole wall.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides an underwater thick fine sand layer hole expansion and agitation device, comprising a pipe body, a drill bit, a cutting and stirring frame and a slurry delivery system, wherein the pipe body comprises an outer pipe and an inner pipe, the upper end of the outer pipe is detachably connected to a double-tube drill pipe with a core pipe, the outer wall of the drill pipe and the outer wall of the outer pipe are both provided with spiral blades, the lower part of the outer pipe is fitted with an inner pipe, and the lower end of the inner pipe is detachably connected to a drill bit;

[0007] The cutting and stirring racks are arranged in a circumferential array outside the tube body, and include an upper cutting plate and a lower cutting plate hinged to the lower end of the upper cutting plate, wherein the upper end of the upper cutting plate is hinged to the outer tube, and the lower end of the lower cutting plate is hinged to the inner tube;

[0008] The slurry conveying system includes a core tube, a slurry delivery channel, an upper through tube and a bottom through tube. The core tube is fixedly arranged at the upper part of the outer tube. The slurry delivery channel includes a drill bit channel, an inner tube channel and plate channels located in the upper cutting plate and the lower cutting plate. The upper through tube receives slurry from between the drill pipe core tube and the inner wall of the drill pipe and passes through the outer tube wall to communicate with the plate channel located in the upper cutting plate. The bottom of the core tube is connected to the bottom of the core tube, the bottom through tube is connected to the drill bit channel, the drill bit channel is connected to the inner tube channel, and the inner tube channel is connected to the plate channel located in the lower cutting plate through a connecting pipe. A slurry outlet hole is provided on one side of the upper cutting plate and the lower cutting plate near the hinge of the upper cutting plate and the lower cutting plate, and the slurry outlet hole is connected to the plate channel.

[0009] Furthermore, the inner wall of the outer tube is provided with a plurality of guide grooves, and the outer wall of the inner tube is provided with protrusions at positions corresponding to the guide grooves. The guide grooves and the protrusions match and enable the outer tube and the inner tube to slide relative to each other.

[0010] Furthermore, the width of the spiral blades arranged on the outer tube wall increases from bottom to top. This arrangement realizes the gradual peeling of the protective layer on one side of the hole of the wall guard ring when the expander moves downward, which is equivalent to leaving time for the formation of the wall guard ring and the strengthening of its strength, while allowing all spiral blades to share the workload of cutting the slurry-soil mixture in the hole, and further reducing the surrounding pressure for the expansion and stirring of the expander. The double-liquid slurry-soil solidification process begins with the initial setting of the slurry-soil mixture, and then its strength gradually increases over time.

[0011] The upper end of the outer tube is threadedly connected to the drill rod, the core tube is threadedly connected to the core tube of the drill rod to receive slurry from the core tube of the drill rod, and the lower end of the inner tube is threadedly connected to a drill bit.

[0012] Furthermore, the upper cutting plate and the lower cutting plate are both plate-shaped structures, and a cutting edge is provided on the side of the upper cutting plate and the lower cutting plate opposite to the slurry outlet hole, and the cutting edge of the upper cutting plate and the cutting edge of the lower cutting plate are located on the same side.

[0013] Furthermore, the upper part of the core tube is fixedly connected to the inner wall of the outer tube through a plurality of connecting plates, and the lower part of the core tube is fixedly connected to the inner wall of the outer tube through an inner partition; one end of the upper through tube is fixedly arranged in the inner partition, and the top ends of the two are flush.

[0014] Furthermore, the inner tube is provided with a plurality of positioning hoops, which are used to control the downward progress of the outer tube to adjust the maximum opening degree of the cutting and stirring frame. When the outer tube slides down and contacts the positioning hoops, the positioning hoops will prevent the outer tube from sliding down, and the cutting and stirring frame reaches the maximum opening degree.

[0015] Furthermore, the drill bit is an ultra-short tapered drill bit with a "Y" or "X" cross-section or an ultra-short spiral blade drill bit with a short thread pitch. When the drill bit is an ultra-short tapered drill bit, the cone head angle is 60 to 150°. When the soil is hard and dense, the cone head angle takes a small value, and when the soil is slightly harder and denser, the cone head angle takes a large value. The selection requirements of the drill bit are: it must be able to drill in, but not drill in too fast, so that the soil around the borehole can be fully stirred and a solidification ring can be formed to lay the foundation for the borehole wall protection.

[0016] Furthermore, the outer tube is provided with two overflow holes symmetrically in radial direction, the overflow holes are located below the inner partition, and a sealing sheet made of rubber is provided outside the overflow holes, the sealing sheet is embedded in the outer tube, the outer surface of the sealing sheet is flush with or slightly concave with the outer wall of the outer tube, and one end of the sealing sheet is fixedly connected to the outer tube. The setting of the overflow hole is used to adjust the fluid migration and pressure difference inside and outside the tube when the expander is working, so as to reduce adverse effects.

[0017] The lengths of the inner tube and the outer tube of the expander of the present invention are determined according to the expansion bottom size and the expansion range diameter. It can be processed into multiple series of sizes, and the inner tube and the outer tube are assembled according to the expansion range in engineering applications. At the same time, the expansion range of the expander can be further adjusted with the help of a positioning hoop. Assume that the diameter of the drill hole is a, the diameter of the expansion range is b, and the outer diameter of the outer tube is d. Affected by the hinge of the upper cutting plate and the lower cutting plate, the inner tube and the outer tube will not be completely in contact in the vertical direction, and there is a minimum spacing c. Therefore, the effective length of the upper / lower cutting plate (the length from the slurry hole to the outer tube wall or the inner tube wall) is

[0018] Upper / lower cutting plate length =

[0019] The upper cutting plate and the lower cutting plate can also be of different lengths, in which case the effective heights of the inner tube and the outer tube can be significantly different. If the existing upper / lower cutting plate length exceeds the length calculated above, it is necessary to add several positioning hoops (pre-processed) to increase the c value.

[0020] The second aspect of the present invention provides a method for drilling a hole in a thick silty sand layer underwater, which is specifically:

[0021] First, determine the expansion elevation range and wall thickness based on the properties and thickness of the fine sand layer within the borehole range, and then determine the size of the expander; use the expander to expand and solidify the periphery of the borehole, and the slurry flowing out of the expander under pressure is mixed with the loosened soil and quickly begins to solidify, forming a mortar wall ring with a certain strength and thickness around the borehole. At the same time, the spiral blades of the drill rod connected to the expander deliver the modified fine mortar mixture (low-strength slurry-soil solidification body) in the borehole to the outside of the hole, and finally form a hole.

[0022] The above-mentioned underwater thick fine sand layer hole forming method specifically comprises the following steps:

[0023] Step 1: Calculate the size of the expansion range and the top and bottom elevations based on the properties of the fine sand and the thickness of the proposed retaining wall.

[0024] Step 2: Determine the size of the expander, including the height and diameter of the outer and inner tubes, the cone angle of the drill bit, and the size of the cutting and stirring frame. The diameters of the inner and outer tubes are usually selected based on the principle that the outer envelope diameter of the expander is 1 / 3 to 2 / 3 of the borehole diameter when the cutting and stirring frame is closed. The lengths of the upper and lower cutting plates of the cutting and stirring frame are selected based on the principle that the slurry outlet reaches the outer boundary of the expansion and stirring range when the cutting and stirring frame is fully opened. The cone angle of the drill bit is selected based on the principle that the drill bit does not produce a large downward drilling behavior when the cutting and stirring frame is opened to the designed opening. The height of the inner and outer tubes is selected according to the length of the upper and lower cutting plates. If the upper and lower cutting plates of the existing cutting and stirring frame are too long, the requirements can be met by adding positioning hoops.

[0025] Step 3: Select the matching drill pipe, choose a double-tube drill pipe with a core tube, and the outer wall of the drill pipe is equipped with spiral blades.

[0026] Step 4: Slurry preparation: Determine the curing strength and thickness of the retaining ring according to geological conditions and engineering requirements, and then prepare a slurry with a matching initial setting time and strength. When using double slurry, determine the reasonable initial setting time of each single slurry and the mixture of the two slurries.

[0027] Step 5: Drill a straight hole to the upper elevation of the expansion range according to the specifications, and maintain a reasonable height of the wall slurry in the hole.

[0028] Step 6: Use an expander to expand and drain the straight hole described in step 5 until it reaches the designed expansion drilling bottom elevation, so that a protective wall ring with a thickness of 5 to 20 cm is formed on the hole wall.

[0029] Step 7: After the expansion and drilling work is completed, stop the slurry delivery and lift the expander to form a hole. After the hole is formed, the slurry wall ring is still retained and the borehole wall is stable.

[0030] Step 8: If the designed borehole needs to be extended downward and the soil conditions are good, use a conventional drill bit with a drill pipe to drill to the designed bottom elevation using mud wall protection, remove the drill, and drill the hole.

[0031] Furthermore, step 6 specifically includes:

[0032] Step 61: lower the expander to the bottom of the straight hole in step 5 (i.e., the upper elevation of the expansion range), and open the cutting stirring frame to contact the hole wall;

[0033] Step 62: Start the slurry transportation, spin the expander through the drill pipe, the expander outer tube moves downward, the cutting and stirring frame spins and cuts the soil on the hole wall, and the two slurries are transported along the slurry transportation system and flow out from the slurry outlet holes in the upper cutting plate and the lower cutting plate under pressure, enter the loosened soil, and further mix with the soil in the subsequent stirring of the cutting and stirring frame and quickly set, forming a relatively hard slurry-soil complex. At the same time, the cutting and stirring frame further opens and cuts and stirs the soil to form a slurry-soil mixture. At this stage, due to the influence of the resistance of the soil at the bottom of the hole, the downward resistance of the drill bit is greater than the cutting and stirring resistance, and the spinning effect of the drill pipe on the expander is mainly to gradually open the cutting and stirring frame to the designed maximum opening.

[0034] Step 63: When the cutting and mixing frame is gradually opened to the maximum, the drill pipe pressure is increased, and the drill bit is drilled downward. At the same time, the cutting and mixing frame is rotary-cutting the soil around the hole at the maximum opening degree, and the slurry continuously flows out from the slurry outlet hole under pressure and mixes with the loosened soil to form a slurry-soil mixture.

[0035] Step 64: The expander continues to move downward until it reaches the designed expansion drilling bottom elevation.

[0036] Further, when forming a hole in thick fine sand under diving conditions, the spiral blade size of the drill pipe is suitable with the borehole diameter, for realizing full soil discharge. In step 64, the lower end of the expansion stirrer is drilled into the bottom quick self-made retaining ring at the same time, and the spiral blade of the upper drill pipe is fully discharged.

[0037] Furthermore, when drilling in thick fine sand under high pressure water conditions, the starting elevation of the expansion and stirring in step 1 is selected above the lowest elevation where no sudden surge occurs at the bottom of the hole, and the sudden surge safety factor is 1.05, that is, the sum of the pressure of the wall slurry in the hole and the deadweight of the soil layer between the top of the fine sand layer and the starting elevation of the expansion and stirring is greater than 1.05 times the pressure of the pressure head. The spiral blade of the matching drill pipe selected in step 3 is 20 to 50 cm smaller than the diameter of the borehole, which is used to achieve partial soil discharge, reduce stirring resistance, and provide a 10 to 25 cm protective layer for the designed wall retaining ring to promote its formation of a qualified wall retaining ring under high pressure water conditions. In step 64, while the lower end of the expansion and stirring device is drilling, the lower part quickly makes a self-made wall retaining ring, and the residual soil in the hole outside the upper drill pipe provides a 10 to 25 cm protective layer for the wall retaining ring, which can promote its formation of a qualified wall retaining ring under high pressure water conditions. Step 7 also includes lifting the expander and then delivering the filling slurry. When the expander is slowly lifted up and leaves the expansion zone, the slurry delivery is stopped, the expander continues to be lifted up to the hole mouth and moved away from the hole position, and then replaced with a conventional drill bit with a drill pipe, using a mud wall protection method to drill through the slurry-soil combination within the hole range of the high-pressure silt fine sand layer, and drill down to the designed hole bottom elevation position, and then lift the drill to form a hole.

[0038] The present invention has the following beneficial effects:

[0039] 1. The expander of the present invention is used to spray slurry into the periphery of the designed aperture and stir the slurry. The slurry and fine sand are mixed, and the slurry-soil mixture outside the borehole wall is left to form a 5-20 cm thick wall protection ring, which ensures the self-stabilization of the borehole wall. The slurry infiltrates into the hole and is easy to form a slurry-soil solidified body with low bonding strength. The low bonding strength slurry-soil mixture is divided by the spiral blades on the outer tube and the drill rod and transported toward the hole mouth, which reduces the soil confining pressure in the stirring area, and also reduces the resistance of the expander to rotate and stir.

[0040] 2. When the spiral blades on the drill pipe are equal to the size of the borehole, the spiral blades of the drill pipe play a role in full soil discharge. The lower end is drilled and the retaining ring is quickly made, and the upper drill pipe is fully drained. When the fine sand layer is rich in high-pressure water, the size of the spiral blades on the drill pipe is 20 to 50 cm smaller than the diameter of the borehole, and is equal to the size of the spiral blades at the top of the outer tube. This structure adds a 10 to 25 cm protective layer to the retaining ring on one side of the borehole, which enhances the formation of a high-quality retaining ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The structure of the expansion and stirring device for drilling holes in thick and fine sand layers underwater according to the present invention is shown in FIG. Figure 1 .

[0042] Figure 2 The structure of the expansion and stirring device for drilling holes in thick and fine sand layers underwater according to the present invention is shown in FIG. Figure 2 .

[0043] Figure 3 The present invention is a schematic structural diagram of an underwater expander for drilling holes in thick silt and fine sand layers when the cutting and stirring frame is opened to the designed maximum opening.

[0044] Figure 4 The present invention is a schematic diagram of the three-dimensional structure of an expander for drilling holes in a thick and fine sand layer underwater.

[0045] Figure 5 The present invention is a schematic structural diagram of an upper cutting plate and a lower cutting plate of an expander for drilling holes in a thick underwater fine sand layer.

[0046] Figure 6 The present invention is a schematic diagram of the structure of an outer tube, an inner tube and an upper through tube in an expander for drilling holes in a thick underwater fine sand layer.

[0047] Figure 7 It is a schematic diagram of the straight hole in step 5 of Example 2 of a method for drilling a hole in a thick silt and fine sand layer underwater according to the present invention.

[0048] Figure 8 This is a schematic diagram of a straight hole placed under the expander in step 61 of Example 2 of an underwater thick fine sand layer drilling method of the present invention.

[0049] Fig. 9This is a schematic diagram of the downward expansion and stirring of the expander in step 63 of Example 2 of an underwater thick fine sand layer hole-forming method of the present invention.

[0050] Fig.10 This is a schematic diagram of step 64 of Example 2 of an underwater thick fine sand layer drilling method of the present invention after reaching the designed expansion and stirring drilling bottom elevation.

[0051] Fig.11 This is a schematic diagram of a method for drilling a hole in an underwater thick fine sand layer after drilling in Example 2 of the present invention.

[0052] Fig.12 This is a schematic diagram of the downward extension of the drilling in Example 2 of a method for forming a hole in an underwater thick silt and fine sand layer according to the present invention.

[0053] Fig.13 Schematic diagram of the straight hole in step 5 of embodiment 3 of the method for forming a hole in a thick silt-fine sand layer underwater according to the present invention.

[0054] Fig.14 This is a schematic diagram of a straight hole placed under the expander in step 61 of Example 3 of an underwater hole-forming method for thick fine sand layer of the present invention.

[0055] Fig.15 This is a schematic diagram of the downward expansion and stirring of the expander in step 63 of Example 3 of an underwater thick fine sand layer hole forming method of the present invention.

[0056] Fig.16 This is a schematic diagram of step 64 of Example 3 of an underwater thick fine sand layer drilling method of the present invention after reaching the designed expansion and stirring drilling bottom elevation.

[0057] Fig.17 This is a schematic diagram of a method for drilling a hole in a thick silt-fine sand layer underwater after drilling in Example 3 of the present invention.

[0058] Fig.18 It is a schematic diagram of the downward extension of the drilling of Example 3 of the underwater thick fine sand layer drilling method of the present invention.

[0059] In the accompanying drawings, 1 is a drill bit, 2 is an outer tube, 3 is an inner tube, 4 is an upper cutting plate, 5 is a lower cutting plate, 6 is a core tube, 7 is a bottom through tube, 8 is a drill bit channel, 9 is an inner tube channel, 10 is a plate inner channel, 11 is a connecting pipe, 12 is a slurry outlet hole, 13 is a protrusion, 14 is a cutting edge, 15 is a connecting plate, 16 is an inner partition plate, 17 is a positioning hoop, 18 is a wall protection ring, 19 is a slurry-soil mixture, 20 is a sealing plate, 21 is an overflow hole, 22 is fine sand, 23 is wall protection mud, 24 is a conventional drilling tool with a drill pipe, 25 is an upper through tube, and 26 is a spiral blade. DETAILED DESCRIPTION

[0060] The present invention is described in detail below through specific embodiments, but the protection scope of the present invention is not limited to the following embodiments, and any technical solutions that can be thought of by any technician in the field based on the present invention and combined with the common knowledge in the field belong to the protection scope of the present invention.

[0061] Example 1

[0062] like Figures 1 to 6 As shown, an underwater thick fine sand layer hole expansion stirrer includes a pipe body, a drill bit 1, a cutting stirring frame and a slurry conveying system, the pipe body includes an outer pipe 2 and an inner pipe 3, the outer pipe 2 is a steel pipe, the inner diameter is 20-40cm, the wall thickness is 3-5cm, and the length is 50-100cm, the upper end of the outer pipe 2 is threadedly connected with a double-tube drill pipe with a core pipe, the outer wall of the drill pipe and the outer wall of the outer pipe 2 are both provided with spiral blades 26, the lower part of the outer pipe 2 is fitted with the inner pipe 3, specifically, the inner wall of the outer pipe 2 is provided with a plurality of guide grooves, and the outer wall of the inner pipe 3 is provided with protrusions 13 at positions corresponding to the guide grooves, the guide grooves and the protrusions 13 match and can make the outer pipe 2 and the inner pipe 3 slide against each other. The inner pipe 3 is a steel pipe, the outer diameter is the same as the inner diameter of the outer pipe 2, the wall thickness is 2-4cm, and the length is 40-90cm. The outer tube 2 is radially symmetrically provided with two overflow holes 21, the overflow holes 21 have a diameter of 0.8 to 1.2 cm and are located below the inner partition 16, and a sealing piece 20 made of rubber is provided on the outside of the overflow hole 21. The sealing piece 20 is embedded in the outer tube 2, and the outer surface of the sealing piece 20 is flush with or slightly concave with the outer wall of the outer tube 2, and one end of the sealing piece 20 is fixedly connected to the outer tube 2.

[0063] The lower end of the inner tube 3 is threadedly connected with a drill bit 1, and the drill bit 1 is an ultra-short tapered drill bit with a "Y" or "X" cross section or an ultra-short spiral blade drill bit with a short thread pitch. When the drill bit 1 is an ultra-short tapered drill bit, the cone head angle is 60 to 150 degrees. In order to prevent the drill bit 1 from falling off due to back drilling, a bolt can be set to connect the drill bit to the inner tube 3.

[0064] The inner tube 3 is also sleeved with a plurality of positioning hoops 17, which are circular rings with a height of 3 cm to 15 cm, and are used to control the downward progress of the outer tube 2 to adjust the maximum opening degree of the cutting and stirring frame.

[0065] The cutting and stirring racks are arrayed circumferentially outside the tube body, and there are usually 2 or 4 cutting and stirring racks arrayed outside the tube body. The cutting and stirring racks include an upper cutting plate 4 and a lower cutting plate 5 hinged to the lower end of the upper cutting plate 4, the upper end of the upper cutting plate 4 is hinged to the outer tube 2, and the lower end of the lower cutting plate 5 is hinged to the inner tube 3; the upper cutting plate 4 and the lower cutting plate 5 are both plate-shaped structures, and are both made of high-strength steel plates with a thickness of 1.5 to 3 cm. The upper cutting plate 4 and the lower cutting plate 5 are provided with a cutting edge 14 on one side of the rotation direction and a slurry outlet hole 12 on the other side.

[0066] The slurry conveying system includes a core tube 6, a slurry conveying channel, an upper through tube 25 and a bottom through tube 7. The core tube 6 is fixedly arranged at the upper part of the outer tube 2 and is coaxial with the outer tube 2. Specifically, the upper part of the core tube 6 is fixedly connected to the inner wall of the outer tube 2 through a plurality of connecting pieces 15, and the lower part of the core tube 6 is fixedly connected to the inner wall of the outer tube 2 through an inner partition 16. The upper end of the core tube 6 is threadedly connected to the core tube of the drill pipe to receive the slurry from the core tube of the drill pipe. The slurry delivery channel includes a drill bit channel 8, an inner tube channel 9 and an inner plate channel 10 located in the upper cutting plate 4 and the lower cutting plate 5. The upper through pipe 25 receives the slurry from between the drill pipe core tube and the inner wall of the drill pipe and passes through the outer tube 2 to communicate with the inner plate channel 10 located in the upper cutting plate 4. Specifically, one end of the upper through pipe 25 is threadedly connected to the inner partition plate 16, and is embedded in a preset hole groove in the outer tube 2, and ensures that the upper through pipe 25 is not affected when the inner tube 3 and the outer tube 2 are fitted together. The upper through pipe 25 passes through the wall of the outer tube 2 and is connected to the inner plate channel 10 in the upper cutting plate 4. The bottom of the core tube 6 is connected to a bottom through-tube 7, which is connected to a drill hole 8, which is connected to an inner tube hole 9, which is connected to an inner plate hole 10 located in the lower cutting plate 5 through a connecting tube 11; a slurry outlet hole 12 is provided on one side of the upper cutting plate 4 and the lower cutting plate 5 near the hinge of the upper cutting plate 4 and the lower cutting plate 5, and the slurry outlet hole 12 is connected to the inner plate hole 10, and there are 2 to 3 slurry outlet holes 12 on the upper cutting plate 4 and the lower cutting plate 5, and the slurry finally enters the soil from here and mixes with the soil under the stirring of the cutting and stirring frame. The above-mentioned drill hole 8 is in a ⊥ shape, which receives the slurry from the bottom through-tube 7, and is transported to the inner plate hole 10 of the lower cutting plate 5 through the inner tube hole 9 in the inner tube 3, and then flows out under pressure at the slurry outlet hole 12 of the lower cutting plate 5. When two cutting and stirring racks are arranged outside the tube body, the upper cutting plates 4 and the lower cutting plates 5 of the two cutting and stirring racks are both provided with plate channels 10. When four cutting and stirring racks are arranged, only the plate channels 10 in the upper cutting plates 4 of the two symmetrical cutting and stirring racks are connected with the upper through pipe 25, and the adjacent cutting and stirring racks have only the bottom through pipe 7 and the plate channels 10 of the lower cutting plate 5 connected, and the upper cutting plates 4 and the lower cutting plates 5 that do not pass the slurry are not provided with plate channels 10 and are both solid plates.

[0067] The assembly steps of the above-mentioned expander are as follows:

[0068] Step 1: Prepare the outer tube 2, the inner tube 3, the drill bit 1, the positioning hoop 17, the rigid and flexible pipelines, and the connecting parts, and check whether there are any quality problems or hidden dangers.

[0069] Step 2: Install the upper through pipe 25 and pass the upper through pipe 25 through the outer pipe 2; install the bottom through pipe 7.

[0070] Step 3: insert the positioning hoop 17 outside the inner tube 3, insert the inner tube 3 into the outer tube 2; and make the bottom through tube 7 pass out from the bottom of the inner tube 3.

[0071] Step 4: Connect the upper through pipe 25 to the inner channel 10 in the upper cutting plate 4, and hinge the upper cutting plate 4 on the hinge seat of the outer tube 2 wall, and tightly plug the upper through pipe 25 into the inner channel 10 of the plate.

[0072] Step 5: Connect the bottom through tube 7 to the ⊥-shaped drill hole 8 on the drill bit 1, and then connect the drill bit 1 to the lower end of the inner tube 3. The bottom through tube 7 in the tube body will be stored in the outer tube 2 and the inner tube 3 in a spiral manner (similar to a spring).

[0073] Step 6: Use a rigid-flexible pipeline (i.e., connecting pipe 11) to connect the inner tube channel 9 with the plate channel 10 in the lower cutting plate 5, and at the same time hinge the lower cutting plate 5 on the hinge seat of the inner tube 3, and tightly plug the rigid-flexible pipeline into the plate channel 10 of the lower cutting plate 5.

[0074] Step 7: Hinged the upper cutting plate 4 and the lower cutting plate 5. At this point, the expander is assembled. Move the expander according to the working mode of the expander, and check until it is confirmed that the expander is working normally (pay special attention to the connection state of the upper through pipe 25 and the inner plate channel 10 of the upper cutting plate 4, and the state of the connecting pipe between the inner pipe channel 9 and the inner plate channel 10 of the lower cutting plate 5). Check and confirm that the pipe connection is firm and unobstructed by water.

[0075] When in use, the expander is placed at the bottom of the straight hole, the drill bit 1 is blocked by the soil at the bottom of the hole and stops moving downward, the cutting and stirring frame opens and touches the hole wall. The slurry delivery is started, the drill rod is spun, the outer tube 2 of the expander moves downward along the inner tube 3 that fits with it, the cutting and stirring frame spun the soil at the hole wall, the slurry is transported along the slurry delivery system and flows out from the slurry outlet holes 12 of the upper cutting plate 4 and the lower cutting plate 5 under pressure, and enters the loosened soil body. In the stirring of the cutting and stirring frame immediately following, the slurry and the soil body are further mixed and quickly initially solidified and solidified, and the cutting and stirring frame further opens. At this stage, due to the resistance of the soil at the bottom of the hole, the downward resistance of the drill bit 1 is greater than the cutting and stirring resistance, and the spinning effect of the drill rod on the expander is mainly to gradually open the cutting and stirring frame to the designed opening (the drill bit 1 rotates under pressure, which will also produce a certain amount of downward drilling. The larger the cone angle of the drill bit 1, the denser the soil at the bottom of the hole, and the smaller the amount of downward drilling). When the cutting and stirring frame is gradually opened to the maximum, the pressure of the drill rod is increased, and the drill bit 1 drills downward. At the same time, the cutting and stirring frame cuts the soil around the hole at the maximum opening, and continuously discharges slurry from the slurry outlet hole to mix the loose soil. After the double slurry is mixed with the loose soil, it quickly sets initially, thereby forming a hard ring layer with a certain bonding strength and good integrity around the borehole. As the drill bit 1 moves downward, the hard ring layer is in a relatively static state under the lateral support of the outer tube 2 and the drill rod, and its strength is further improved with time, playing the role of protecting the borehole wall, which is called the slurry soil wall protection ring 18. The slurry in the borehole is relatively small, and it is stirred and cut by the outer tube 2 and the spiral blades 26 on the drill rod, and finally forms a low bonding strength slurry soil mixture 19. The slurry soil mixture 19 is divided by the outer tube 2 and the spiral blades 26 on the drill rod, and transported toward the hole mouth, which reduces the soil confining pressure in the mixing area, and also reduces the resistance of the agitator to rotate and stir.

[0076] When the spiral blade 26 on the drill rod is equal to the size of the drill hole, the spiral blade 26 of the drill rod plays a role of full soil discharge. Thus, the lower end of the expander is drilled and the self-made retaining ring 18 is quickly made, and the upper spiral drill rod is fully discharged. This method is called a method of drilling a hole once with a self-made retaining ring 18.

[0077] When the fine sand layer 22 is rich in high-pressure water, the water pressure fluctuations in the borehole are large and complex, and it is difficult to form a qualified retaining ring 18 by the homemade retaining ring 18 drilling method. At this time, the spiral blades 26 on the drill rod should be 20 to 50 cm smaller than the borehole diameter, and the size is comparable to the spiral blades 26 at the top of the outer tube 2. This structure adds a 10 to 25 cm protective layer to the retaining ring 18 on one side of the borehole, which enhances the formation of a high-quality retaining ring 18. Then the expansion stirrer is reversed and replaced with conveying filling slurry. The cutting and stirring frame is gradually retracted, and the orifice on the expansion stirrer is raised. Then a conventional drill 24 with a drill rod is used to drill the hole. Since the fine sand 22 in the hole range has become a low-bonding strength slurry-soil mixture 19, that is, the underwater fine sand 22 has been modified, the conventional drill 24 with a drill rod can be used to drain the soil and drill. This hole-forming method is a homemade slurry-soil retaining wall hole-forming method.

[0078] Example 2

[0079] The method of drilling holes in thick fine sand under diving conditions (a method of drilling holes once with a homemade retaining ring) includes the following steps:

[0080] Step 1: Calculate the size of the expansion range and the top and bottom elevations according to the properties of the fine sand 22 and the thickness of the wall retaining ring 18 to be set.

[0081] Step 2: Determine the size of the expander, including the height and diameter of the outer tube 2 and the inner tube 3, the cone angle of the drill bit 1, and the size of the cutting and stirring frame. The diameters of the inner tube 3 and the outer tube 2 are usually selected based on the principle that the outer envelope diameter of the expander is 1 / 3 to 2 / 3 of the borehole diameter when the cutting and stirring frame is closed, the lengths of the upper cutting plate 4 and the lower cutting plate 5 of the cutting and stirring frame are selected based on the principle that the slurry outlet 12 reaches the outer boundary of the expansion and stirring range when the cutting and stirring frame is fully opened, the cone angle of the drill bit 1 is selected based on the principle that the drill bit 1 does not produce a large downward drilling behavior when the cutting and stirring frame is opened to the designed opening, and the heights of the inner tube 3 and the outer tube 2 are selected based on the lengths of the upper cutting plate 4 and the lower cutting plate 5. If the upper cutting plate 4 and the lower cutting plate 5 of the existing cutting and stirring frame are too long, the requirements can be met by adding a positioning hoop 17.

[0082] Step 3: Select a matching drill rod, a double-tube drill rod with a core tube is selected, and a spiral blade 26 is provided on the outer wall of the drill rod. The size of the spiral blade 26 of the drill rod is equivalent to the diameter of the drill hole, which is used to achieve full soil discharge.

[0083] Step 4: Slurry preparation: According to the geological conditions and engineering requirements, the curing strength and thickness of the retaining ring 18 are comprehensively determined, and then the slurry with the corresponding initial setting time and strength is prepared. When using double slurry, the reasonable initial setting time of each single slurry and the two slurries after mixing should be determined. Cement slurry and water glass are usually used.

[0084] Step 5: Drill a straight hole to the upper elevation of the expansion range according to the specification requirements, and maintain a reasonable height of the wall slurry 23 in the hole, such as Figure 7 shown.

[0085] Step 6: Use an expander to expand and fully drain the straight hole in step 5 until the designed expansion and drilling bottom elevation is reached, so that a wall protection ring 18 with a thickness of 5 to 20 cm is formed on the hole wall. This step specifically includes:

[0086] Step 61: Lower the expander to the bottom of the straight hole in step 5 (i.e., the upper elevation of the expansion range), and cut the stirring frame to open and contact the hole wall, such as Figure 8 shown.

[0087] Step 62: Start the slurry transportation, spin the expander and stirrer through the drill pipe, the outer tube 2 of the expander and stirrer moves downward, the cutting and stirring frame peels and cuts the soil on the hole wall, and the two slurries are transported through their respective paths (the water glass is transported through the core tube 6, the bottom through tube 7, the drill hole 8, the inner tube hole 9 and the plate inner hole 10 of the lower cutting plate 5 in sequence, and the cement slurry is transported through the upper through tube 25 and the plate inner hole 10 of the upper cutting plate 4 in sequence) and flow out from the slurry outlet holes 12 in the upper cutting plate 4 and the lower cutting plate 5 respectively under pressure, enter the peeled and loosened soil, and further mix with the soil in the subsequent stirring of the cutting and stirring frame and quickly set, forming a relatively hard slurry-soil complex, while the cutting and stirring frame further opens and cuts and stirs the soil to form a slurry-soil mixture 19. At this stage, due to the influence of the resistance of the soil at the bottom of the hole, the downward resistance of the drill bit 1 is greater than the cutting and stirring resistance, and the spinning effect of the drill pipe on the expander and stirrer is mainly to gradually open the cutting and stirring frame to the designed maximum opening.

[0088] Step 63: When the cutting and stirring frame is gradually opened to the maximum, the drill pipe pressure is increased, and the drill bit 1 is drilled downward. At the same time, the cutting and stirring frame is cut with the maximum opening degree around the hole. The slurry is continuously discharged from the slurry outlet hole 12 and mixed with the loosened soil to form a slurry-soil mixture 19. Fig. 9 shown.

[0089] Step 64: The expander continues to move downward until it reaches the designed expansion drilling bottom elevation. Fig.10 As shown. Since the spiral blade 26 on the drill rod is comparable to the borehole size, the drill rod plays a full soil discharge role. At this time, the lower end of the expansion stirrer drills in while the lower part quickly makes the retaining ring 18, and the spiral blade 26 of the upper drill rod fully discharges soil.

[0090] Step 7: After the expansion and drilling work is completed, stop the slurry delivery, lift the expansion and drilling tool, such as Fig.11 After the hole is formed, the wall protection ring 18 is still retained, and the hole wall is stable.

[0091] Step 8: If the designed borehole needs to be extended downward and the soil conditions are good, a conventional drill 24 with a drill rod is used to drill to the designed bottom elevation position in a mud wall protection manner, and the drill is removed to form a hole. Fig.12 shown.

[0092] Example 3

[0093] The method for forming holes in thick fine sand under high pressure water bearing conditions (self-made slurry soil wall forming method) includes the following steps:

[0094] like Figures 13 to 18 As shown,

[0095] The steps of this embodiment are basically the same as those of embodiment 2, and the similarities are not repeated here. The difference is that:

[0096] The starting elevation of the expansion and stirring in step 1 is selected above the lowest elevation where no sudden surge occurs at the bottom of the hole, and the sudden surge safety factor is 1.05, that is, the sum of the pressure of the wall protection mud 23 in the hole and the deadweight of the soil layer between the top of the fine sand layer 22 and the starting elevation of the expansion and stirring is greater than 1.05 times the pressure of the pressure head.

[0097] The spiral blade 26 of the matching drill rod selected in step 3 is 20 to 50 cm smaller than the borehole diameter, and is used to achieve partial soil discharge and reduce stirring resistance.

[0098] In step 64, while the lower end of the expander is drilling, a self-made retaining ring 18 is quickly formed at the lower part, and the residual soil in the hole outside the upper spiral drill rod provides a 10-25 cm protective layer for the retaining ring 18, which can promote it to form a qualified retaining ring 18 under high pressure water conditions.

[0099] After the expander is lifted up in step 7, the filling slurry with low strength is conveyed instead. As the expander is slowly lifted up, the cutting and stirring frame stirs and gathers during the reverse rotation, and the original slurry remaining in the tube just reinforces the bottom of the expansion range. Afterwards, with the arrival of the filling slurry, the filling slurry will fill the space left by the expansion and stirring device, thereby maintaining the stability of the expansion area, especially the stability of the high-strength ring layer on the periphery. When the expander is slowly lifted up and leaves the expansion area, the slurry delivery is stopped, and the expander continues to be lifted up to the hole mouth and moves away from the hole position. Then replace it with a conventional drilling tool 24 with a drill rod, adopt a mud wall protection method, drill through the slurry-soil combination in the hole range of the high-pressure gouache fine sand layer 22, and drill down to the designed hole bottom elevation position, and then lift the drill to form a hole.

[0100] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structure, features and principles of the patent scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A method for drilling holes in a thick, fine sand layer underwater, characterized in that: A hole is formed by using an underwater thick fine sand layer drilling expander, the expander comprising a pipe body, a drill bit (1), a cutting and stirring frame and a slurry conveying system, the pipe body comprising an outer pipe (2) and an inner pipe (3), the upper end of the outer pipe (2) being detachably connected to a double-tube drill rod with a core pipe, the outer wall of the drill rod and the outer wall of the outer pipe (2) being provided with spiral blades (26), the lower part of the outer pipe (2) being fitted with an inner pipe (3), the lower end of the inner pipe (3) being detachably connected to a drill bit (1); The cutting and stirring frames are arranged in a circumferential array outside the tube body, and comprise an upper cutting plate (4) and a lower cutting plate (5) hinged to the lower end of the upper cutting plate (4); the upper end of the upper cutting plate (4) is hinged to the outer tube (2), and the lower end of the lower cutting plate (5) is hinged to the inner tube (3); The slurry delivery system comprises a core tube (6), a slurry delivery channel, an upper through tube (25) and a bottom through tube (7); the core tube (6) is fixedly arranged at the upper portion of the outer tube (2); the slurry delivery channel comprises a drill bit channel (8), an inner tube channel (9) and an inner plate channel (10) located in the upper cutting plate (4) and the lower cutting plate (5); the upper through tube (25) receives slurry from between the core tube of the drill pipe and the inner wall of the drill pipe and passes through the wall of the outer tube (2) and the inner plate channel (10) located in the upper cutting plate (4). ), the bottom of the core tube (6) is connected to a bottom through-tube (7), the bottom through-tube (7) is connected to a drill hole (8), the drill hole (8) is connected to an inner tube hole (9), the inner tube hole (9) is connected to an inner plate hole (10) located in a lower cutting plate (5) through a connecting pipe (11); a slurry outlet hole (12) is provided on one side of the upper cutting plate (4) and the lower cutting plate (5) near a hinged joint of the upper cutting plate (4) and the lower cutting plate (5); The method comprises the following steps: Step 1: Calculate the size of the expansion and mixing range and the top and bottom elevations according to the properties of the fine sand (22) and the thickness of the wall retaining ring (18) to be set; Step 2: Determine the size of the expander, including the height and diameter of the outer tube (2) and the inner tube (3), the cone angle of the drill bit (1) and the size of the cutting and stirring frame; select the diameters of the inner tube (3) and the outer tube (2) based on the principle that the outer envelope diameter of the expander is 1 / 3 to 2 / 3 of the borehole diameter when the cutting and stirring frame is closed; select the lengths of the upper cutting plate (4) and the lower cutting plate (5) of the cutting and stirring frame based on the principle that the slurry outlet hole (12) reaches the outer boundary of the expansion and stirring range when the cutting and stirring frame is fully opened; select the cone angle of the drill bit (1) based on the principle that the drill bit does not produce a large downward drilling behavior when the cutting and stirring frame is opened to the designed opening; and select the heights of the inner tube (3) and the outer tube (2) based on the lengths of the upper cutting plate (4) and the lower cutting plate (5); Step 3: Select a matching drill pipe, a double-tube drill pipe with a core pipe, and a spiral blade (26) is provided on the outer wall of the drill pipe; Step 4: slurry preparation: comprehensively determine the curing strength and thickness of the retaining ring (18) according to geological conditions and engineering requirements, and then prepare a slurry with a matching initial setting time and strength; Step 5: Drill a straight hole to the upper elevation of the expansion range according to the specification requirements, and maintain a reasonable height of the wall protection mud (23) in the hole; Step 6: Use an expander to expand and drain the vertical hole in step 5 until the designed expansion drilling bottom elevation is reached, so that a protective wall ring (18) with a thickness of 5 to 20 cm is formed on the hole wall; Step 7: After the expansion and drilling work is completed, stop the slurry delivery and lift the expansion and agitator to form a hole; Step 8: If the designed borehole needs to be extended downward and the soil conditions are good, a conventional drilling tool (24) with a drill pipe is used to drill to the designed hole bottom elevation position in a mud wall protection manner, and the drill is removed to complete the hole.

2. The method for drilling holes in a thick underwater fine sand layer according to claim 1, characterized in that: Step 6 specifically includes: Step 61: lower the expander to the bottom of the straight hole in step 5, and cut the stirring frame to open and contact the hole wall; Step 62: start the slurry transportation, spin the expander and stirrer through the drill pipe, the outer tube of the expander and stirrer moves downward, the cutting and stirring frame spins and cuts the soil on the hole wall, the two slurries are transported along the slurry transportation system and flow out from the slurry outlet holes (12) in the upper cutting plate (4) and the lower cutting plate (5) under pressure, enter the loosened soil, and are further mixed with the soil during the subsequent stirring of the cutting and stirring frame and quickly set to form a relatively hard slurry-soil complex. At the same time, the cutting and stirring frame further opens and cuts and stirs the soil to form a slurry-soil mixture (19); Step 63: When the cutting and stirring frame is gradually opened to the maximum, the drill pipe pressure is increased, the drill bit (1) is moved downward, and at the same time, the cutting and stirring frame is used to rotary cut the soil around the hole at the maximum opening, and the slurry is continuously discharged from the slurry outlet hole (12) and mixed with the loosened soil to form a slurry-soil mixture (19); Step 64: The expander continues to move downward until it reaches the designed expansion drilling bottom elevation.

3. The method for drilling holes in a thick underwater fine sand layer according to claim 2, characterized in that: When drilling in thick fine sand (22) under submerged conditions, the size of the spiral blade (26) of the drill rod is equivalent to the diameter of the drill hole, which is used to achieve full soil discharge; in step 64, the lower end of the expander is drilled and the lower self-made retaining ring (18) is quickly formed, and the spiral blade (26) of the upper drill rod fully discharges the soil.

4. The method for drilling holes in a thick underwater fine sand layer according to claim 2, characterized in that: When drilling in thick fine sand (22) under high pressure water conditions, the starting elevation of the expansion and stirring in step 1 is selected to be above the lowest elevation where no sudden surge occurs at the bottom of the hole, and the sudden surge safety factor is 1.05; the spiral blade (26) of the matching drill rod selected in step 3 is 20 to 50 cm smaller than the diameter of the borehole, so as to achieve partial soil discharge; in step 64, while the lower end of the expander and stirrer is drilling, the lower part quickly forms a self-made wall protection ring (18), and the residual soil in the hole outside the upper drill rod provides a 10 to 25 cm protective layer for the wall protection ring (18); step 7 also includes the step of replacing the conveying of filling slurry after the expander and stirrer is lifted up and leaves the expansion and stirring area, stopping the conveying of slurry, and continuing to lift the expander and stirrer to the hole mouth and move away from the hole position, and then replacing it with a conventional drilling tool (24) with a drill rod, adopting a mud wall protection method, drilling through the slurry-soil combination in the hole range of the high pressure water fine sand layer, and drilling down to the designed hole bottom elevation position, and then lifting the drill to form a hole.

5. The method for drilling holes in a thick, fine sand layer underwater according to claim 1, characterized in that: The inner wall of the outer tube (2) is provided with a plurality of guide grooves, and the outer wall of the inner tube (3) is provided with protrusions (13) at positions corresponding to the guide grooves. The guide grooves and the protrusions (13) match each other and enable the outer tube (2) and the inner tube (3) to slide relative to each other.

6. The method for drilling holes in a thick underwater fine sand layer according to claim 1, characterized in that: The upper cutting plate (4) and the lower cutting plate (5) are both plate-shaped structures, and a cutting edge (14) is provided on the side of the upper cutting plate (4) and the lower cutting plate (5) opposite to the pulp outlet hole (12), and the cutting edge (14) of the upper cutting plate (4) and the cutting edge (14) of the lower cutting plate (5) are located on the same side.

7. The method for drilling holes in a thick, fine sand layer underwater according to claim 1, characterized in that: The upper portion of the core tube (6) is fixedly connected to the inner wall of the outer tube (2) via a plurality of connecting plates (15), the lower portion of the core tube (6) is fixedly connected to the inner wall of the outer tube (2) via an inner partition (16), and one end of the upper through tube (25) is fixedly disposed in the inner partition (16).

8. The method for drilling holes in a thick, fine sand layer underwater according to claim 1, characterized in that: The outer shell of the inner tube (3) is provided with a plurality of positioning hoops (17), and the positioning hoops (17) are used to control the downward progress of the outer tube (2) so as to adjust the maximum opening degree of the cutting and stirring frame.

9. The method for drilling holes in a thick, fine-silt underwater sand layer according to claim 1, characterized in that: The drill bit (1) is an ultra-short conical drill bit with a "Y"-shaped or "cross"-shaped cross section, or an ultra-short drill bit with a spiral blade and a short thread pitch.

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