In-situ cast steel sheet concrete shaft lining construction method for drilling

Abstract

The application discloses a cast-in-situ steel plate concrete shaft lining construction method for drilling well by a drilling method, and is characterized in self-up-to-down and section support construction, before high support construction of an n-th support section, mud in the n-th support section is first pumped out of a to-be-constructed wellbore, and the mud composition which has not been pumped out below the n-th support section is kept relatively stable; n is a positive integer; after the mud in the n-th support section is pumped out of the to-be-constructed wellbore, an oil cylinder support hanging plate and an arc-shaped steel plate piece which constitutes a wellbore inner ring steel plate cylinder are respectively placed into the to-be-constructed wellbore, and the arc-shaped steel plate piece is assembled into the wellbore inner ring steel plate cylinder in the to-be-constructed wellbore. The method provided by the application uses a steel plate to replace a formwork used in a concrete pouring operation of a wellbore intermediate layer, and directly uses a disc surface of a hydraulic oil cylinder support hanging plate as a bottom formwork, so that the operation procedure is simple, and the wellbore construction by using the method provided by the application can save material and time costs and reduce construction costs.

Description

Technical Field

[0001] This invention relates to the field of vertical shaft construction technology. Specifically, it relates to a method for constructing cast-in-place steel plate concrete well walls for drilling wells. Background Technology

[0002] Drilling is a mechanized well-sinking method that uses vertical shaft drilling rigs as the main equipment. First, drill bits are used to break up the formation, while simultaneously using drilling mud for air-lift reverse circulation to remove slag and maintain the wellbore wall. Once the wellbore has reached the designed diameter and depth, the drill bit and drill pipe are lifted from the wellbore to the surface. Then, using the buoyancy of the drilling mud, the prefabricated wellbore wall floats and sinks within the mud-filled wellbore. Figure 4 As shown. After the well wall is lowered to the bottom of the well, backfilling and cementing are carried out to finally form a well structure that meets the engineering requirements.

[0003] However, traditional vertical shaft drilling methods employ the floating and sinking of prefabricated well walls, which presents several challenges, including difficulty in floating, sinking, and high risk of instability. Specifically, firstly, due to geological conditions and wellbore safety requirements, prefabricated well walls are often thick and heavy, making it difficult for them to float in the drilling mud. Secondly, as the wellbore sinking depth increases, the volume of displaced drilling mud also increases. Due to the buoyancy of the drilling mud, the floating prefabricated well wall has difficulty sinking, even if its internal space is filled with counterweight water. Thirdly, as the well depth and drilling diameter increase, the overall vertical instability risk of the floating and sinking well wall increases, and correcting the floating well wall's deviation becomes very difficult.

[0004] Cast-in-place concrete construction of the well wall is one way to solve the above problems. For example, the method provided in CN115182734A discloses a hydraulic sliding formwork for lining the wall of a vertical shaft. The inner and outer formwork used during wall lining are connected to a lifting platform via hydraulic cylinders. In use, the hydraulic cylinders press the formwork firmly against the well wall, and technicians inject concrete grout between the inner and outer formworks. After each section of grouting is completed, the hydraulic cylinders retract the formwork, and then the lifting platform lowers the hydraulic cylinders and formwork together to the next section. However, this method lowers the formwork and lifting platform together, which places high demands on the stability of the suspension system during construction. Furthermore, because the formwork and hydraulic cylinders are fixedly connected, if the hydraulic cylinders malfunction and cannot retract the formwork, the lowering process cannot proceed normally, and it is difficult to successfully raise the shaft. In addition, repairing or replacing the hydraulic cylinders requires dismantling the formwork, which is inconvenient. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide a method for constructing cast-in-place steel plate concrete well walls for drilling wells. The method involves casting in-place concrete for the well wall, and the lowering of the well wall steel plate and the lowering of the hoisting platform are carried out separately. Furthermore, the well wall steel plate is supported by the support shoes of the hydraulic cylinder hoisting platform, making the operation more convenient.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] The construction method for cast-in-place steel plate concrete wellbore in drilling well sinking involves top-down, segmented support construction. Before constructing the support for the nth high support segment, the mud within the nth high support segment is extracted from the wellbore to be constructed, while maintaining the relatively stable composition of the mud not yet extracted below the nth high support segment; n is a positive integer. The stable mud will provide temporary support for the unsupported wellbore. During construction, as long as there is no mud within the currently constructed support segment, normal construction can proceed. If all the mud in the wellbore is extracted at once, it can easily lead to problems such as spalling of the unsupported wellbore.

[0008] The above-described method for constructing cast-in-place steel plate concrete well walls for drilling wells involves using a mud pipe to extract mud from the wellbore to be constructed. One end of the mud pipe is submerged below the mud level within the wellbore, while the other end extends outwards towards the wellhead and branches into two pipes. Each branch pipe is connected to a mud pump. A first valve is installed on the first branch pipe, and a second valve is installed on the second branch pipe. The parameters of the mud in the wellbore are maintained by the mixer and the mud pipe, ensuring the stability of the surrounding rock in the mud-submerged section of the wellbore. The mixer is located outside the lumen of the mud pipe and submerged below the mud level within the wellbore. The mixer is connected to a compressed air pump via an air duct.

[0009] When the mud is extracted from the well shaft to be constructed, the compressed air pump and the first valve are turned off, and the second valve is opened. Under the action of the mud pump connected to the second branch pipeline, the mud is extracted from the well shaft to be constructed through the second branch pipeline.

[0010] During the support construction, the second valve is closed, and the first valve and the compressed air pump are opened. Fresh mud is pumped into the shaft to be constructed by the mud pump connected to the first branch pipeline. The compressed air pump sequentially pumps high-pressure air into the shaft through the air duct and the compressed air hole on the mixer, causing the mud to tumble and flow within the shaft. The high-pressure air introduced into the shaft by the mixer agitates the mud, maintaining stable parameters such as density, viscosity, water loss, mud cake thickness, and pH. Maintaining stable mud density and other parameters is beneficial for maintaining the stability of the surrounding rock below the mud surface. Since the mixer is located outside the mud pipe cavity, the high-pressure air discharged from the mixer is less likely to directly enter the mud pipe cavity, interfering with the flow of fresh mud into the shaft. Simultaneously, the pipe wall of the mud pipe does not restrict the movement of air bubbles formed by the high-pressure air, which facilitates thorough mixing of the mud by the air bubbles.

[0011] The above-described method for constructing cast-in-place steel plate concrete wellbore for drilling well sinking involves circulating the mud in a mud circulation loop under the action of a mud pipe and a mixer, thereby maintaining the parameter properties of the mud in the wellbore to be constructed. The mud circulation loop includes a first mud pipe, a mud pool, a second mud pipe, and the wellbore to be constructed, which are connected end to end and fluidly connected. The mud inlet of the first mud pipe and the mud outlet of the second mud pipe are submerged below the mud level in the wellbore to be constructed. A circulation switch is installed on the pipeline of the second mud pipe. The mixer is located in the lower part of the cavity of the first mud pipe and below the mud level. The mixer is fluidly connected to a compressed air pump through an air duct.

[0012] When the circulation switch is closed, the compressed air pump pumps high-pressure air into the first mud pipe through the air duct and the compressed air hole on the mixer in sequence, so that the mud in the well shaft to be constructed flows into the mud pool through the first mud pipe and is retained in the mud pool.

[0013] When the circulation switch is turned on, the compressed air pump pumps high-pressure air sequentially through the air duct and the compressed air port on the mixer into the first mud pipe. This causes the mud in the wellbore to flow sequentially through the first mud pipe, the mud pool, and the second mud pipe, returning from the mud outlet of the second mud pipe to the wellbore and re-entering the mud inlet of the first mud pipe. Continuous mud circulation keeps the mud composition stable, prevents mud settling, and maintains stable mud density, viscosity, water loss, mud cake thickness, and pH. Maintaining stable mud density and other parameters helps maintain the stability of the surrounding rock below the mud level.

[0014] The above-described method for constructing cast-in-place steel plate concrete well walls for drilling wells involves extracting the mud from the nth support section of the wellbore to be constructed, placing the hydraulic cylinder support plate and the arc-shaped steel plates forming the inner ring steel plate cylinder of the wellbore into the wellbore, and assembling the arc-shaped steel plates into the inner ring steel plate cylinder within the wellbore. A support cylinder is installed on the hydraulic cylinder support plate, and a support shoe is fixedly connected to the free end of the support cylinder. The hydraulic cylinder support plate is tightened against the wellbore through the support shoe. The support plate surface on the upper surface of the hydraulic cylinder support plate serves as the support surface for the inner ring steel plate cylinder of the wellbore, and the bottom end of the grouting annular space between the inner ring steel plate cylinder and the wellbore is sealed. After anchoring the inner ring steel plate cylinder to the wellbore, concrete grouting is performed into the grouting annular space. The support shoe will tighten the well wall, which helps to prevent the hydraulic cylinder support plate from shaking or shifting in the well shaft to be constructed. When the steel plate cylinder of the well wall is placed on the support plate, its weight will be transmitted to the support shoe below the support plate. While the support shoe provides support for the steel plate cylinder of the well wall, the support plate above the support shoe also acts as a bottom formwork when the well wall concrete is poured.

[0015] The above-mentioned method for constructing cast-in-place steel plate concrete well walls for drilling wells includes a mud pipe channel at the center of the support platform, through which the mud pipe and the ventilation duct pass; in step B, one support section is 3-4m high, and the support construction includes the following steps:

[0016] Step A: Carry out construction preparation work; install the derrick and hoisting equipment at the wellhead, and prepare construction materials;

[0017] Step B: Use the mud pipe to pump out the mud from the wellbore until the mud level drops by a height greater than that of one support section.

[0018] Step C: Using the lifting equipment, lower the hydraulic cylinder support plate into the wellbore until the upper surface of the support shoe is coplanar with the virtual plane of the high and low ends of the support section, then stop lowering the hydraulic cylinder support plate; activate the support cylinder installed on the outer ring surface of the hydraulic cylinder support plate ring beam, the support cylinder drives the support shoe to extend towards the well wall and tighten it; the mud pipe passes through the mud pipe channel on the hydraulic cylinder support plate, so that the mud pipe does not need to be pulled out of the wellbore when lowering the hydraulic cylinder support plate, and the mixer connected to the mud pipe can continuously mix the mud;

[0019] Step D: The arc-shaped steel plates that make up the inner ring steel plate cylinder of the well wall are lowered into the well to be constructed. Adjacent arc-shaped steel plates that make up the inner ring steel plate cylinder of the well wall are fixed and sealed together to obtain the inner ring steel plate cylinder of the well wall. The inner ring steel plate cylinder of the well wall is placed on the support plate above the support shoe. Then, the inner ring steel plate cylinder of the well wall is fixed relative to the well wall with anchor rods. One end of the anchor rod extends into the surrounding rock of the well wall, and the other end is equipped with an anchor rod tray. The anchor rod tray abuts against the surface of the inner ring steel plate cylinder of the well wall away from the well wall. Using anchor rods for anchoring helps to firmly fix the inner ring steel plate cylinder of the well wall to the well wall and prevents the inner ring steel plate cylinder of the well wall from falling off after the hydraulic cylinder support plate is lowered.

[0020] Step E: Concrete is poured into the grouting annular space between the inner steel plate cylinder and the well wall through the well wall pouring holes provided on the inner steel plate cylinder. The concrete is then vibrated through the well wall pouring vibration holes provided on the inner steel plate cylinder. After the concrete has dried, the support cylinder drives the support shoe away from the well wall. Concrete vibration helps prevent air bubbles from existing in the intermediate concrete layer after grouting, thus preventing a decrease in the strength of the intermediate concrete layer.

[0021] Step F: Repeat steps B through E until the wellbore construction is complete.

[0022] In the above-mentioned method for constructing cast-in-place steel plate concrete well walls for drilling wells, in step E, the grouting annular space is the annular space between the inner steel plate cylinder of the well wall and the well wall.

[0023] In the above-described method for constructing cast-in-place steel plate concrete well walls for drilling wells, in step C, when the surrounding rock of the well casing is a weak rock layer or an extra-thick soil layer, after the support shoe tightens the well wall and before lowering the arc-shaped steel plate sheet that makes up the inner ring steel plate cylinder of the well wall into the well casing to be constructed, the following steps are performed:

[0024] The arc-shaped steel plates that make up the outer ring steel plate cylinder of the well wall are placed into the well cylinder to be constructed. The adjacent arc-shaped steel plates that make up the outer ring steel plate cylinder of the well wall are fixed and sealed together to obtain the outer ring steel plate cylinder of the well wall. The outer ring steel plate cylinder of the well wall is placed on the support hanging plate above the support shoe.

[0025] After obtaining the outer ring steel plate cylinder of the well wall, grout is injected into the space between the outer ring steel plate cylinder and the well wall using the back filling hole provided on the outer ring steel plate cylinder of the well wall until grout overflows from the back filling return hole provided on the outer ring steel plate cylinder of the well wall. Then the back filling return hole is sealed, and grout is added through the back filling hole. After the grouting is completed, the back filling hole is sealed.

[0026] In step D, the inner ring steel plate cylinder of the well wall is coaxially placed in the inner cavity of the outer ring steel plate cylinder of the well wall. The outer diameter of the inner ring steel plate cylinder is smaller than the inner diameter of the outer ring steel plate cylinder. One end of the anchor rod extends into the surrounding rock of the well wall, passing through the inner ring steel plate cylinder and the outer ring steel plate cylinder in sequence, and then extends into the surrounding rock of the well wall. When the surrounding rock of the well wall is a weak rock layer or an extra-thick soil layer, using both the inner and outer ring steel plate cylinders to support the well wall is beneficial to improving the overall strength and stability of the well wall. Backfilling with grout helps to firmly fix the outer ring steel plate cylinder and the well wall, preventing the outer ring steel plate cylinder from slipping and also preventing gaps between the outer ring steel plate cylinder and the well wall, which would affect the quality and stability of the well wall.

[0027] In step E, the grouting annular space is the annular space between the inner steel plate cylinder of the well wall and the outer steel plate cylinder of the well wall.

[0028] In the above-mentioned construction method for cast-in-place steel plate concrete well walls for drilling well sinking, in step B, one of the support sections is 3-4m high, and the mud pipe and the mixer are used to maintain the parameter performance of the mud in the wellbore.

[0029] In the above-mentioned construction method for cast-in-place steel plate concrete well walls for drilling wells, in step C, the hydraulic cylinder support platform is connected to the bottom of the lower plate of the double-layer working platform by a lifting wire rope. The working platform is lowered into the wellbore along with the hydraulic cylinder support platform by the lifting equipment. When fixing and sealing the arc-shaped steel plate, the construction personnel use the working platform for operation.

[0030] The aforementioned method for constructing cast-in-place steel plate concrete well walls for drilling wells involves a ring beam with a circular structure. A structural beam is fixedly installed in the air within the inner ring of the ring beam to prevent deformation. The structural beam comprises two rectangular frames intersecting in a cross shape, with each frame's four corners fixedly connected to the inner ring surface of the ring beam. When the hydraulic cylinder support platform is lowered, the distance between the lower surface of the hydraulic cylinder support platform and the mud surface is 1–1.2 m. This distance ensures smooth support construction while minimizing the length of the unsupported well wall above the mud surface, ensuring that the vast majority of the unsupported well wall is protected by the mud, thus preventing large-scale collapse of the unsupported well wall.

[0031] In the above-described method for constructing cast-in-place steel plate concrete well walls for drilling wells, the anchor bolts are respectively arranged on both sides of the steel plate connection joint between two adjacent support sections, and are adjacent to the steel plate connection joint; within one support section, the anchor bolts are arranged in two or more parallel circles along the circumference of the well wall. Arranging one circle of anchor bolts adjacent to each side of the steel plate connection joint helps ensure the firmness of the fixation between the inner and outer rings of the steel plate cylinder and the well wall.

[0032] The technical solution of the present invention achieves the following beneficial technical effects:

[0033] 1. This invention utilizes the advantages of unmanned drilling in traditional shaft sinking methods, proposing a shaft wall construction method that uses a suspended platform for cast-in-place steel plate concrete support in the upper part of the shaft and unremoved mud for surrounding rock protection in the lower part of the shaft. This method ensures the stability of the unsupported section of the shaft wall while avoiding the problems of "not being able to float," "not being able to sink," and "high risk of instability" that occur in traditional shaft sinking methods where precast shaft walls float and sink.

[0034] 2. The wellbore construction method for drilling wells proposed in this invention ensures the safety of cast-in-place steel plate concrete wellbore construction by using anchor bolts, hydraulic cylinder-supported lifting platforms, and lifting wire ropes for joint support. Simultaneously, steel plates replace the formwork used for pouring the intermediate layer of concrete in the wellbore, and the surface of the hydraulic cylinder-supported lifting platform directly serves as the bottom formwork, simplifying the operation process. Compared to the original precast steel plate concrete wellbore using floating and sinking methods, the thickness of the cast-in-place steel plate concrete wellbore for drilling wells proposed in this invention can be significantly reduced, saving material costs and lowering construction expenses.

[0035] 3. Compared with the existing vertical hydraulic slipform method, the method provided in this invention lowers the inner and outer ring steel plate cylinders of the well wall and the hydraulic cylinder support plate separately. This can effectively prevent the hydraulic cylinder support plate from getting stuck in the well and unable to move when the support cylinder fails. Moreover, when the usage time is the same, the total time for the support cylinder to support the template in this invention is shorter, which is beneficial to extending the service life of the hydraulic cylinder.

[0036] 4. During support construction, the mud in the wellbore protects the well wall below the support section height. Furthermore, under the influence of the mud pipe and mixer and their specific positional relationship in this invention, the mud in the wellbore can maintain stable properties and is not prone to settling, thus providing good protection for the well wall. Attached Figure Description

[0037] Figure 1 A cross-sectional view of the well shaft during the construction process of cast-in-place steel plate concrete in an embodiment of the present invention;

[0038] Figure 2Schematic diagram of the working state of the working platform and the hydraulic cylinder support platform in the embodiment of the present invention;

[0039] Figure 3 A schematic diagram of the hydraulic cylinder support hanging plate structure in an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the traditional precast well wall sinking construction method in the background art of this invention;

[0041] Figure 5 A schematic diagram of the mixer structure in an embodiment of the present invention;

[0042] Figure 6 Schematic diagram a of the working principle of the mud pipe and mixer in this embodiment of the invention;

[0043] Figure 7 Schematic diagram b of the working principle of the mud pipe and mixer in this embodiment of the invention;

[0044] Figure 8 Schematic diagram c showing the working principle of the mud pipe and mixer in this embodiment of the invention.

[0045] The reference numerals in the diagram are as follows: 1-Lifting wire rope; 2-Working platform; 3-Hydraulic cylinder support platform; 301-Support shoe; 302-Supporting hydraulic cylinder; 303-Hydraulic cylinder support platform control platform; 304-Supporting platform surface; 305-Ring beam; 306-Structural beam; 307-Mud pipe channel; 4-Inner ring steel plate cylinder of well wall; 5-Outer ring steel plate cylinder of well wall; 6-Intermediate concrete layer; 7-Anchor bolt; 8-Steel plate joint; 9-Backfilling hole; 10- 11-Backfilling return hole; 12-Wall wall pouring vibration hole; 13-Wall wall pouring hole; 14-Mud pipe; 1401-First mud pipe; 1402-Second mud pipe; 15-Mixer; 1501-Compressed air hole; 16-Mud; 1601-Mud surface; 17-Surrounding rock of wellbore; 18-Air duct; 19-Mud pit; 20-Circulation switch; 22-First valve; 23-Second valve; 24-Compressed air pump. Detailed Implementation

[0046] Example 1

[0047] In this embodiment, the inner ring steel plate cylinder 4 and the outer ring steel plate cylinder 5 of the well wall are used to replace the inner and outer formwork used in traditional well wall support construction, respectively, for well wall support construction. Specifically, the following steps are included:

[0048] (1) Prepare for well wall construction. After the vertical shaft drilling rig reaches the designed well depth, the drill bit, drill rod and other drilling tools are lifted from the well to the surface. The well is only filled with mud. Remove the vertical shaft drilling rig equipment at the wellhead and build a ground derrick, stabilizing vehicle and other lifting equipment for well wall construction at the wellhead. Prepare the lifting platform, tools and other well wall construction materials.

[0049] (2) Perform mud pumping. For example... Figure 1 As shown, during mud pumping, the mud pipe 14 is inserted below the mud surface 1601 inside the wellbore to pump the mud 16 to the surface for treatment. The mud level drop height for each pumping operation must be greater than the height of the first support section. The mud 16 itself provides support for the wellbore wall; if all the mud 16 is pumped out at once, problems such as spalling may occur in the wellbore. The support section height should ideally be 3-4 meters. If the surrounding rock 17 of the wellbore is relatively firm, the height of the first support section can be appropriately increased.

[0050] In this embodiment, one end of the mud pipe 14 is submerged below the mud surface 1601 in the wellbore to be constructed, and the other end is located outside the wellhead and extends into two branch pipes. Each branch pipe is connected to a mud pump. A first valve 22 is installed on the first branch pipe, and a second valve 23 is installed on the second branch pipe. The mixer is located outside the cavity of the mud pipe 14 and submerged below the mud surface 1601 in the wellbore to be constructed. The mixer 15 is fluidly connected to the compressed air pump 24 through the air duct 18. When the mud is extracted from the wellbore to be constructed, the compressed air pump 24 and the first valve 22 are turned off, and the second valve 23 is opened. The mud 16 is extracted from the wellbore to be constructed through the second branch pipe by the mud pump connected to the second branch pipe.

[0051] During the support construction process, mud 16 is needed to maintain the stability of the unsupported section of the wellbore. This requires the mud's parameters to remain stable and to form a relatively stable mud cake on the wellbore wall in the mud-submerged section. The mud's parameters include density, viscosity, water loss, mud cake thickness, and pH. Depending on the different formation lithology conditions, technicians can set the values ​​of the mud parameters that need to be maintained.

[0052] The parameters and properties of the mud 16 are mainly maintained by the mixer 15 and the mud pipe 14. During the support construction, the mud pipe is used to add a small amount of fresh mud to the wellbore to adjust the parameters and properties of the mud, while the main function of the mixer 15 is to stir the mud, stabilize the mud composition, and prevent the mud from settling.

[0053] Maintaining the performance parameters of the mud slurry needs to be synchronized with the support construction process. During the support construction, the second valve 23 needs to be closed, and the first valve 22 and the compressed air pump 24 need to be opened. Fresh mud slurry is pumped into the shaft to be constructed by the mud slurry pump connected to the first branch pipeline. The compressed air pump 24 pumps high-pressure air into the shaft to be constructed through the air duct 18 and the compressed air hole 1501 on the mixer 15. The high-pressure air will blow bubbles into the mud slurry 16 in the shaft to be constructed. These bubbles will move in the mud slurry 16, causing the mud slurry 16 to tumble and flow in the shaft to be constructed, which plays a role in agitating the mud slurry. In this embodiment, the air duct 8 is located outside the cavity of the mud slurry pipe 14, such as Figure 7 As shown. In some other embodiments, the duct 8 may also be located within the cavity of the slurry pipe 14 to save space in the slurry pipe channel 307, such as... Figure 8 As shown. When the air duct 8 is located outside the cavity of the mud pipe 14, it is preferable to place the mixer 15 in the middle or below the mud to allow the mixer 15 to function better.

[0054] (3) Lowering the hoisting platform. After the mud level drops and exposes the height of one support section, the hoisting platform is lowered as a whole. The hoisting platform includes a working hoisting platform 2 and a hydraulic cylinder support hoisting platform 3. The working hoisting platform 2 is a double-layered platform, with its upper and lower surfaces connected by a lifting wire rope 1, used to carry construction materials and personnel. The hydraulic cylinder support hoisting platform 3 is connected to the working hoisting platform 2 by the lifting wire rope 1. When the hoisting platform is lowered into the wellbore, the upper surface of the working hoisting platform 2 is suspended from the lifting equipment at the wellhead by the lifting wire rope 1, the lower surface of the working hoisting platform 2 is suspended below the upper surface, and the hydraulic cylinder support hoisting platform 3 is suspended below the lower surface of the working hoisting platform 2. When lowering the working hoisting platform 2 and the hydraulic cylinder support hoisting platform 3, the lifting equipment releases the lifting wire rope 1, allowing the working hoisting platform 2 and the hydraulic cylinder support hoisting platform 3 to gradually descend.

[0055] The hydraulic cylinder support plate 3 has a disc-shaped structure, including a ring beam 305 and a structural beam 306 installed in the air within the ring beam 305. The structural beam 306 includes two rectangular frames intersecting in a cross shape to support the ring beam 305 and prevent deformation. When lowered into the well, the upper surface of the hydraulic cylinder support plate 3 has a support plate surface 304, and at the center of the support plate surface 304 is a mud pipe channel 307 for the mud pipe 14 to pass through. After passing through the mud pipe channel 307, the mud pipe 14 passes through the center of the structural beam 306 and extends below the mud surface 1601. In this way, the raising or lowering of the hydraulic cylinder support plate 3 in the wellbore will not affect the operation of the mud pipe 14 and the mixer 15, enabling continuous mud pumping and lowering of the plate.

[0056] When the hydraulic cylinder support platform 3 is lowered to the designated position, the technicians activate the support cylinder 302 installed on the outer ring surface of the ring beam 305 via the hydraulic cylinder support platform control platform 303 mounted on the support platform surface 304. The free end of the support cylinder 302 is connected to a support shoe 301. Under hydraulic pressure, the support shoe 301 extends towards the well wall and tightens the surrounding rock of the wellbore. Figure 1 and Figure 2 As shown, at this time, the upper surface of the support shoe 301 and the virtual plane at the high and low ends of this support section are coplanar, and the distance between the mud slurry surface 1601 and the lower surface of the hydraulic cylinder support plate 3 is about 1m.

[0057] (4) Assembly and backfilling grouting of the outer ring steel plate cylinder 5 of the well wall. The outer ring steel plate cylinder 5 of the well wall is composed of multiple arc-shaped steel plates. First, the arc-shaped steel plates that make up the outer ring steel plate cylinder 5 of the well wall are lowered using the hoisting wire rope 1. Then, the construction personnel assemble and weld the adjacent arc-shaped steel plates that make up the outer ring steel plate cylinder 5 of the well wall on the working platform 2. The assembled outer ring steel plate cylinder 5 of the well wall is placed on the support plate surface 304 above the support shoe 301 of the hydraulic cylinder support plate 3. Figure 3 As shown. During the construction of the second and subsequent support sections of the well wall, it is also necessary to weld each of the arc-shaped steel plates forming the outer ring steel plate cylinder 5 of the well wall in this section to its adjacent upper part, forming the arc-shaped steel plate cylinder 5 of the previous section of the well wall. The outer ring steel plate cylinder 5 of the well wall has pre-processed backfilling holes 9 and backfilling grout return holes 10. After the assembly and welding of the outer ring steel plate cylinder 5, construction personnel stand on the work platform 2 and use the backfilling holes 9 on the outer ring steel plate cylinder 5 to perform backfilling grouting using cement slurry or cement mortar. Figure 2 As shown. After the grout overflows from the backfill return hole 10, the backfill return hole 10 is sealed. Then, grouting is added through the backfill hole 9 to ensure that the backfill material 11 is compacted. Finally, the backfill hole 9 is sealed.

[0058] (5) Assembly of the inner steel plate 4 of the well wall. The inner ring steel plate cylinder 4 of the well wall is composed of multiple arc-shaped steel plates. First, the arc-shaped steel plates that make up the inner ring steel plate cylinder 4 of the well wall are lowered using the hoisting wire rope 1. Then, the construction workers assemble and weld the adjacent arc-shaped steel plates that make up the inner ring steel plate cylinder 4 on the working platform 2. The assembled inner ring steel plate cylinder 4 of the well wall is placed on the support platform 304 above the support shoe 301 of the hydraulic cylinder support platform 3, and is coaxial with the outer ring steel plate cylinder 5 of the well wall. Figure 3 As shown; when constructing the well wall of the second and subsequent support sections, it is also necessary to weld each of the arc-shaped steel plates that make up the inner ring steel plate cylinder 4 of the well wall in this section to the arc-shaped steel plates that are adjacent to each other on the upper part of the section and make up the inner ring steel plate cylinder 4 of the well wall in the previous section.

[0059] (6) Anchor Bolt Construction. After the inner and outer ring steel plate cylinders of the well wall are assembled, anchor bolt construction is carried out on the working platform 2. Anchor bolts 7 pass through the inner and outer ring steel plate cylinders of the well wall in sequence and are anchored in the surrounding rock 17 of the well wall. The anchor bolt tray is pressed against the side of the inner ring steel plate cylinder 4 away from the well wall. Anchor bolts 7 can be arranged in two or more rings within one support section, such as... Figure 3 As shown, at least one ring of anchor bolts should be arranged on each side of the steel plate connection joint 8 between adjacent high steel plates. The number of anchor bolts in each ring should be determined by comprehensive calculation based on the overall weight of a section of the well wall, the bearing capacity of the hydraulic cylinder support plate 3, and the lifting force of the lifting wire rope 1. The main function of the anchor bolts 7 is to prevent the well wall or hydraulic cylinder support plate 3 from falling into the mud when the weight of a section of the well wall is too large and the bearing capacity of the hydraulic cylinder support plate 3 is insufficient. At the same time, it can improve the safety factor of the lifting wire rope 1.

[0060] (7) Well wall pouring operation. For example... Figure 3 As shown, after the inner and outer ring steel plate cylinders of the well wall are assembled and the anchor bolts are installed, the inner and outer ring steel plate cylinders of the well wall become the side templates for the well wall pouring. A grouting annular space is formed between the inner and outer ring steel plate cylinders of the well wall. The support plate surface 304 of the hydraulic cylinder support plate 3 serves as the bottom template for the well wall pouring, sealing the bottom end of the grouting annular space. Then, the well wall concrete pouring pipe is lowered, and the well wall is poured through the well wall pouring hole 13 reserved on the inner ring steel plate cylinder 4. The concrete is vibrated through the well wall pouring vibration hole 12 reserved on the inner ring steel plate cylinder 4 to ensure the compactness of the concrete pouring. After the concrete dries, the intermediate concrete layer 6 is formed. At this time, the free end of the support hydraulic cylinder 302 is retracted, driving the support shoe 301 away from the well wall.

[0061] (8) Repeat steps (2) to (7) until the construction of the cast-in-place steel plate concrete well wall for the entire drilling method well sinking is completed.

[0062] In this embodiment, both the inner ring steel plate cylinder 4 and the outer ring steel plate cylinder 5 are used during well wall support construction. In other embodiments, depending on the geological and engineering conditions, only the inner ring steel plate cylinder 4 can be used, and the above step (4) can be omitted. In this case, a grouting annular space is formed between the inner ring steel plate cylinder 4 and the well wall. Especially when the surrounding rock 17 of the well is relatively solid, using only the inner ring steel plate cylinder 4 can achieve the same support effect as using both the inner ring steel plate cylinder 4 and the outer ring steel plate cylinder 5. In addition, in this embodiment, adjacent arc-shaped steel plates are connected by welding. In other embodiments, adjacent arc-shaped steel plates can also be connected by bolts, rivets, etc., as long as the connection is firm and there is no grout leakage at the steel plate connection seam 8.

[0063] Example 2

[0064] In this embodiment, the wellbore support construction steps are the same as in Embodiment 1. The main difference lies in the mud pumping method and the means of maintaining mud parameters and performance during the support construction process.

[0065] like Figure 6 As shown, in this embodiment, the mud pipe 14 includes a first mud pipe 1401 and a second mud pipe 1402. The mud inlet of the first mud pipe 1401 and the mud outlet of the second mud pipe 1402 are submerged below the mud surface 1601 in the well shaft to be constructed. The first mud pipe 1401, the mud pool 19, the second mud pipe 1402 and the well shaft to be constructed are connected end to end and fluid is connected to form a mud circulation loop. The mixer 15 is located in the lower part of the cavity of the first mud pipe 1401 and below the mud surface 1601. The mixer 15 is fluidly connected to the compressed air pump 24 through the air duct 18. A circulation switch 20 is installed on the pipeline of the second mud pipe.

[0066] like Figure 5 As shown, the mixer 15 is the outlet of compressed air (high-pressure air), which is made of a section of steel pipe with the bottom closed. Many compressed air holes 1501 are drilled on its pipe wall. After a large amount of high-pressure air is ejected from the compressed air holes 1501, it is quickly dispersed into the mud 16 in the first mud pipe 1401. This causes the mud 16 in the first mud pipe 1401 above the mixer 15 to surge upward along the pipe cavity of the first mud pipe 1401, so that a pressure difference is generated at the mud inlet at the top and bottom of the first mud pipe 1401. The mud 16 in the well shaft to be constructed continuously enters the first mud pipe 1401.

[0067] When it is necessary to pump out the mud, the circulation switch 20 should be turned off. At this time, the mud 16 in the shaft to be constructed flows into the mud pool 19 through the first mud pipe 1401 and remains in the mud pool 19. It will not return to the shaft to be constructed. The mud 16 can be manually removed from the mud pool 19.

[0068] When mud pumping is not required, the circulation switch 20 should be opened. At this time, the mixer and mud circulation loop maintain the stability of the mud composition and prevent mud settling. Because when the circulation switch 20 is open, the mud that entered the mud tank 19 will flow back into the wellbore to be constructed and re-enter the mud inlet of the first mud pipe 1401, continuously circulating in the mud circulation loop. In this way, no additional mud stirring is required, and the mud parameters can remain stable, making sedimentation less likely. Stable mud parameters are beneficial for maintaining the stability of the wellbore wall in the mud-submerged section.

[0069] Compared to the technical solution in Example 1 where the mixer 15 is placed outside the mud pipe 14, the technical solution in this embodiment, where the mixer 15 is placed inside the mud pipe, is more effective in stabilizing the wellbore. This is because, when the mixer 15 is placed inside the mud pipe, the air bubbles formed by the high-pressure air discharged from the mixer 15 are confined within the first mud pipe 1401, preventing impact and disturbance to the mud cake adhering to the well wall, and making it less likely for the mud cake to fall off. Therefore, it can better maintain the stability of the surrounding rock of the wellbore in the mud-submerged section. In addition, in this embodiment, the mud circulates continuously inside the wellbore to be constructed and outside the wellhead under the action of pressure difference and gravity, so the mud 16 in this embodiment is more uniform than that in Example 1.

[0070] When the mixer 15 is placed inside the cavity of the mud pipe 14, the high-pressure air discharged from it will cause the mud inside the cavity to surge upwards. Furthermore, the air discharged through the mixer 15 is difficult to escape from the lower end of the mud pipe cavity, thus failing to agitate the mud. Therefore, under conditions where there is no mud circulation loop (such as in Example 1), care should be taken not to place the mixer 15 inside the mud pipe cavity, especially not in the middle of the mud pipe cavity.

[0071] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for constructing cast-in-place steel plate concrete well walls for well sinking using drilling methods, characterized in that, The support construction proceeds from top to bottom in segments. Before constructing the support of the nth support segment, the mud (16) inside the nth support segment is first extracted from the well shaft to be constructed, and the composition of the mud (16) that has not yet been extracted below the nth support segment remains relatively stable; n is a positive integer. The mud (16) is extracted from the wellbore to be constructed using a mud pipe (14); one end of the mud pipe (14) is submerged below the mud surface (1601) in the wellbore to be constructed, and the other end of the mud pipe (14) extends out of the wellhead and extends into two branch pipes, each of which is connected to a mud pump. A first valve (22) is installed on the first branch pipe, and a second valve (23) is installed on the second branch pipe; the parameters of the mud (16) in the wellbore to be constructed are maintained by the action of the mixer (15) and the mud pipe (14) so ​​that the surrounding rock (17) of the wellbore submerged by the mud (16) remains stable; the mixer is located outside the cavity of the mud pipe (14) and submerged below the mud surface (1601) in the wellbore to be constructed, and the mixer (15) is fluidly connected to the compressed air pump (24) through the air pipe (18); When the mud (16) is extracted from the well shaft to be constructed, the compressed air pump (24) and the first valve (22) are turned off, and the second valve (23) is opened. Under the action of the mud pump connected to the second branch pipeline, the mud (16) is extracted from the well shaft to be constructed through the second branch pipeline. During the support construction process, the second valve (23) is closed, the first valve (22) and the compressed air pump (24) are opened, and fresh mud is pumped into the shaft to be constructed by the mud pump connected to the first branch pipeline. The compressed air pump (24) pumps high-pressure air into the shaft to be constructed through the air duct (18) and the air pressure hole (1501) on the mixer (15) in sequence, so that the mud (16) rolls and flows in the shaft to be constructed. After the mud (16) in the nth support section is extracted from the well shaft to be constructed, the hydraulic cylinder support plate (3) and the arc-shaped steel plates that make up the inner ring steel plate cylinder (4) of the well wall are respectively placed into the well shaft to be constructed, and the arc-shaped steel plates are assembled into the inner ring steel plate cylinder (4) of the well wall in the well shaft to be constructed; a support cylinder (302) is installed on the hydraulic cylinder support plate (3), and a support shoe (302) is fixedly connected to the free end of the support cylinder (302). 01), the hydraulic cylinder support plate (3) is supported by the support shoe (301) to tighten the well wall. The support plate surface (304) on the upper surface of the hydraulic cylinder support plate (3) serves as the support surface of the inner ring steel plate cylinder (4) of the well wall and seals the bottom end of the grouting annular space between the inner ring steel plate cylinder (4) of the well wall and the well wall. After the inner ring steel plate cylinder (4) of the well wall is anchored to the well wall, concrete grouting is performed in the grouting annular space.

2. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 1, characterized in that, The mud (16) circulates in the mud circulation loop under the action of the mud pipe (14) and the mixer (15) to maintain the parameter performance of the mud (16) in the wellbore to be constructed and to keep the surrounding rock (17) of the wellbore submerged by the mud (16) stable; the mud circulation loop includes a first mud pipe (1401), a mud pool (19), a second mud pipe (1402), and the wellbore to be constructed, which are connected end to end and have fluid conduction in sequence; the first The mud inlet of a mud pipe (1401) and the mud outlet of a second mud pipe (1402) are submerged below the mud surface (1601) in the well shaft to be constructed. A circulation switch (20) is installed on the pipeline of the second mud pipe. The mixer (15) is located in the lower part of the cavity of the first mud pipe (1401) and below the mud surface (1601). The mixer (15) is fluidly connected to the compressed air pump (24) through the air duct (18). When the circulation switch (20) is closed, the compressed air pump (24) pumps high-pressure air into the first mud pipe (1401) through the air duct (18) and the air pressure hole (1501) on the mixer (15) in sequence, so that the mud (16) in the well shaft to be constructed flows into the mud pool (19) through the first mud pipe (1401) and is stored in the mud pool (19); When the circulation switch (20) is turned on, the compressed air pump (24) pumps high-pressure air into the first mud pipe (1401) through the air duct (18) and the compressed air hole (1501) on the mixer (15) in sequence, so that the mud (16) in the well shaft to be constructed flows through the first mud pipe (1401), the mud pool (19) and the second mud pipe (1402) in sequence, flows back from the mud outlet of the second mud pipe (1402) to the well shaft to be constructed, and re-enters the mud inlet of the first mud pipe (1401).

3. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 1, characterized in that, A mud pipe channel (307) is provided at the center of the support platform (304), through which the mud pipe (14) and the air duct (18) pass; in step B, the height of one of the support sections is 3 to 4 m, and the support construction includes the following steps: Step A: Carry out construction preparation work; install the derrick and hoisting equipment at the wellhead, and prepare construction materials; Step B: Use the mud pipe (14) to pump out the mud (16) in the wellbore until the mud level (1601) drops by a height greater than that of a support section; Step C: Use the lifting equipment to lower the hydraulic cylinder support plate (3) into the wellbore until the upper surface of the support shoe (301) is coplanar with the virtual plane of the high and low ends of the support section, and stop lowering the hydraulic cylinder support plate (3); start the support cylinder (302) installed on the outer ring surface of the ring beam (305) of the hydraulic cylinder support plate (3), and the support cylinder (302) drives the support shoe (301) to extend towards the well wall and tighten the well wall; Step D: The arc-shaped steel plates that make up the inner ring steel plate cylinder (4) of the well wall are placed into the well to be constructed. The adjacent arc-shaped steel plates that make up the inner ring steel plate cylinder (4) of the well wall are fixed and sealed together to obtain the inner ring steel plate cylinder (4). The inner ring steel plate cylinder (4) of the well wall is placed on the support plate (304) above the support shoe (301). Then, the inner ring steel plate cylinder (4) of the well wall is fixed relative to the well wall with the anchor rod (7). One end of the anchor rod (7) extends into the surrounding rock (17) of the well wall, and the other end is equipped with an anchor rod tray. The anchor rod tray abuts against the surface of the inner ring steel plate cylinder (4) away from the well wall. Step E: Concrete is poured into the grouting annular space between the inner ring steel plate cylinder (4) and the well wall through the well wall pouring hole (13) set on the inner ring steel plate cylinder (4) of the well wall, and the concrete is vibrated through the well wall pouring vibration hole (12) set on the inner ring steel plate cylinder (4) of the well wall. After the concrete dries, the support cylinder (302) drives the support shoe (301) away from the well wall. Step F: Repeat steps B through E until the wellbore construction is complete.

4. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 3, characterized in that, In step E, the grouting annular space is the annular space between the inner steel plate cylinder (4) of the well wall and the well wall.

5. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 3, characterized in that, In step C, when the surrounding rock (17) of the well casing is a weak rock layer or an extra-thick soil layer, after the support shoe (301) tightens the well wall, and before the arc-shaped steel plate that makes up the inner ring steel plate cylinder (4) of the well wall is lowered into the well casing to be constructed, the following steps are performed: Step C-1: Place the arc-shaped steel plates that make up the outer ring steel plate cylinder (5) of the well wall into the well cylinder to be constructed, and fix and seal the adjacent arc-shaped steel plates that make up the outer ring steel plate cylinder (5) of the well wall together to obtain the outer ring steel plate cylinder (5). The outer ring steel plate cylinder (5) of the well wall is placed on the support hanging plate (304) above the support shoe (301). Step C-2: After obtaining the outer ring steel plate cylinder (5) of the well wall, use the back filling hole (9) set on the outer ring steel plate cylinder (5) of the well wall to perform back filling grouting between the outer ring steel plate cylinder (5) and the well wall until the grout overflows from the back filling return hole (10) set on the outer ring steel plate cylinder (5) of the well wall, then seal the back filling return hole (10), and replenish the grout through the back filling hole (9). After the grouting is completed, seal the back filling hole (9). In step D, the inner ring steel plate cylinder (4) of the well wall is coaxially placed in the inner cavity of the outer ring steel plate cylinder (5) of the well wall. The outer diameter of the inner ring steel plate cylinder (4) of the well wall is smaller than the inner diameter of the outer ring steel plate cylinder (5) of the well wall. The end of the anchor rod (7) that extends into the surrounding rock (17) of the well wall passes through the inner ring steel plate cylinder (4) and the outer ring steel plate cylinder (5) of the well wall in sequence, and then extends into the surrounding rock (17) of the well wall. In step E, the grouting annular space is the annular space between the inner ring steel plate cylinder (4) of the well wall and the outer ring steel plate cylinder (5) of the well wall.

6. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 3, characterized in that, In step C, the hydraulic cylinder support plate (3) is connected to the bottom of the lower plate of the double-layer working plate (2) by the lifting wire rope (1). The working plate (2) is lowered into the well shaft together with the hydraulic cylinder support plate (3) by the lifting equipment. When fixing and sealing the arc-shaped steel plate, the construction personnel use the working plate (2) to operate.

7. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 3, characterized in that, The ring beam (305) is a circular structure. A structural beam (306) is fixedly installed in the air on the inner ring of the ring beam (305). The structural beam (306) is used to prevent the ring beam (305) from deforming. The structural beam (306) includes two rectangular frames. The two rectangular frames intersect in a cross shape. The four corners of each rectangular frame are fixedly connected to the inner ring surface of the ring beam (305). When the lowering of the hydraulic cylinder support plate (3) is stopped, the distance between the lower surface of the hydraulic cylinder support plate (3) and the mud surface (1601) is 1 to 1.2 m.

8. The method for constructing cast-in-place steel plate concrete well walls for drilling well sinking according to claim 3, characterized in that, The anchor bolts (7) are respectively arranged on both sides of the steel plate connection joint (8) between two adjacent support sections and are adjacent to the steel plate connection joint (8); within one support section, the anchor bolts (7) are arranged in two or more circles parallel to the circumference of the well wall.

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