Karst area pile foundation construction drilling machine and construction method thereof

Abstract

The invention provides a karst area pile foundation construction drilling machine and a construction method thereof, and belongs to the technical field of pile foundation construction.An outer pile casing is buried in the preset pile bottom position of a karst ground to be constructed, then the drilling machine is used for conducting pile foundation construction based on the outer pile casing, and a cushion layer is poured after pile foundation construction is completed; through reasonable construction procedure arrangement and multiple measures and technical means of presetting the pile bottom, the outer pile casing and the cushion layer, the problems of hole forming difficulty, hole collapse risk, slurry leakage, drill jamming and the like are well solved, and the technical effects of improving the construction efficiency and the pile forming quality and ensuring the bearing capacity and the structural stability of a pile foundation are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation construction, and more specifically, to a pile foundation construction drill rig and its construction method in karst areas. Background Art

[0002] Karst areas refer to special geomorphic forms formed by the long-term dissolution of soluble rocks such as limestone and dolomite by corrosive water. Due to the reduction of rock strength and the enhancement of permeability, problems such as insufficient foundation bearing capacity, collapse of the underlying karst cave roof, ground subsidence, and uneven foundation settlement often occur in karst areas. When constructing bridge pile foundations in karst areas, the stress on the hole wall of the drill hole is uneven, which easily leads to problems such as hole deviation, hole collapse, drill sticking, drill burying, mud leakage, and concrete loss. In addition, the existence of karst caves significantly increases the uncertainty of pile foundation construction, posing great challenges to the construction.

[0003] In the prior art, backfilling, manual hole digging, or vibrating full casing pile foundation construction equipment is usually used for construction. However, the above methods still have the following disadvantages: 1) During the pouring of pile foundation concrete, due to the existence of karst caves, the concrete pressure may cause the failure of the retaining wall structure, resulting in concrete leakage or loss; 2) It is difficult to control the construction quality; 3) The construction period is prolonged; and the construction cost is significantly increased.

[0004] Therefore, there is an urgent need for a high-efficiency pile foundation construction method in karst areas. Summary of the Invention

[0005] The purpose of the present invention is to provide a pile foundation construction drill rig and its construction method in karst areas to solve at least one technical problem existing in the prior art.

[0006] The present invention protects a pile foundation construction method in karst areas. The method includes conducting an investigation of pile foundation data on the karst area to be constructed to obtain the depth and diameter of the pile to be made;

[0007] According to the depth and diameter of the pile to be made, an outer casing is buried at the preset pile bottom position on the karst ground to be constructed;

[0008] Using a drill rig to carry out pile foundation construction based on the outer casing; wherein, the drill rig is provided with a crawler-type mobile wheel set;

[0009] After the pile foundation construction is completed, the foundation pit of the bearing platform is excavated to expose the pile head;

[0010] Chisel the pile head until the pile head steel bars are exposed, and lap the pile head steel bars with the bearing platform steel bars;

[0011] Pour a cushion layer at the bottom of the foundation pit of the bearing platform;

[0012] Bind the lapped pile head steel bars and the bearing platform steel bars on the cushion layer.

[0013] Pour the bearing platform concrete by the screw conveyor pump pouring method.

[0014] Further, the preferred method is that the cushion layer is a C25 plain concrete cushion layer; the thickness of the cushion layer is 15 - 25 cm.

[0015] Further, the preferred method is that after the step of chiseling the pile head until the pile head steel bars are exposed, a pile head steel bar pretreatment step is further included; wherein, the pile head steel bar pretreatment includes grinding, straightening and rust removal operations.

[0016] Further, the preferred method is that the outer casing includes a buried section and a protection section; the buried section is buried in the ground of the karst area; the protection section is exposed outside the ground of the karst area; the protection section provides a construction space for the drill bit of the drill rig.

[0017] Further, the preferred method is that the height of the protection section is 50 - 100 cm.

[0018] In the second aspect, the present invention also protects a drill rig for pile foundation construction in karst areas, which is applied to the pile foundation construction steps of the above-mentioned pile foundation construction method in karst areas; the drill rig includes a drill bit, an operation platform for providing power to the drill bit, a moving wheel set arranged below the operation platform, and a support assembly for connecting the operation platform and the drill bit;

[0019] The support assembly includes a support arm, a suspension rope, a winch, a first guide wheel and a second guide wheel; wherein, the support arm is movably arranged on the operation platform, the first guide wheel is arranged in the middle of the support arm, and the second guide wheel is arranged at the top of the support arm; the suspension rope is led out from the winch, sequentially bypasses the first guide wheel and the second guide wheel, and is connected to the drill bit at the end of the suspension rope;

[0020] A slewing bearing is arranged between the operation platform and the moving wheel set, and the moving wheel set is of a crawler structure.

[0021] Further, the preferred structure is that a third guide wheel is arranged at the connection between the end of the suspension rope and the drill bit, and the third guide wheel is a fixed pulley.

[0022] Further, the preferred structure is that the number of the third guide wheels arranged is at least two.

[0023] Further, the preferred structure is that the support arm is movably connected to the operation platform through an electric push rod and a movable bearing.

[0024] Further, a preferred structure is that the drill bit is a certain type of drill bit; wherein, the upper and lower ends of the drill bit are set as frustum shapes; the middle section of the drill bit is cylindrical.

[0025] As described above, for the karst area pile foundation construction drill rig and its construction method of the present invention, by burying an outer casing at the preset pile bottom position of the karst ground to be constructed, then using the drill rig to carry out pile foundation construction based on the outer casing, and pouring a cushion after the pile foundation construction is completed; through multiple measures of preset pile bottom, outer casing and cushion, it is possible to prevent the potential risk that the concrete pressure may cause the failure of the retaining structure and lead to concrete leakage or loss during the pouring of pile foundation concrete due to the existence of karst caves; on the premise of ensuring the quality control of pile foundation construction in karst areas, by strictly controlling the depth and diameter of pile making, and using an outer casing that does not need to be recovered for pile foundation construction, the technical effects of shortening the construction period and reducing the construction cost are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] By referring to the following description in conjunction with the drawings and the content of the claims, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easier to understand. In the drawings:

[0027] Figure 1 is a flow chart of a karst area pile foundation construction method according to an embodiment of the present invention.

[0028] Figure 2 is a structural diagram of a drill rig for karst area pile foundation construction according to an embodiment of the present invention.

[0029] Wherein, 1, operation platform; 2, mobile wheel set; 3, drill bit; 4, support arm; 5, first guide wheel; 6, second guide wheel; 7, suspension rope. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is obvious that these embodiments can also be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form for the purpose of facilitating the description of one or more embodiments.

[0031] It should be understood that the terms "horizontal", "vertical", "upper", "lower", "top", "middle", "length", "inner", "bottom", etc. indicating orientation or position relationships are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0032] Unless otherwise clearly stipulated and defined, terms such as "installation", "connection", "attachment", "fixation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or capable of communicating with each other; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Embodiment 1

[0034] The following will describe each embodiment of the present invention in detail with reference to the accompanying drawings.

[0035] Figure 1 It is a schematic flow chart of a pile foundation construction method in karst areas according to an embodiment of the present invention.

[0036] The present invention protects a pile foundation construction method in karst areas, as Figure 1 shown, the method includes the following steps.

[0037] S110. Conduct an investigation of pile foundation data for the karst area to be constructed, and obtain the depth and diameter of the pile.

[0038] In the specific implementation process, before pile foundation construction in karst areas, a comprehensive geological investigation must be carried out to obtain accurate geological data. This includes information such as karst caves, soil caves, and groundwater levels. Through means such as drilling and geophysical exploration, key data such as the depth and diameter of the pile are obtained, providing a basis for subsequent pile foundation design and construction. According to the investigation results, optimize the pile foundation design to ensure that the pile foundation can effectively avoid karst caves or penetrate weak strata, improving the stability and bearing capacity of the pile foundation. In addition, in addition to investigation and design, preparations for steel bars, concrete, and drilling rigs should also be made before construction.

[0039] S120. According to the depth and diameter of the pile, bury an outer casing at the preset pile bottom position on the karst ground to be constructed. That is, after the investigation and design are completed, pile foundation construction is carried out. According to the depth and diameter of the pile, bury an outer casing at the preset pile position on the karst ground to ensure that the outer casing penetrates the upper weak strata. The main function of the outer casing is to stabilize the hole wall, prevent cave-ins, and provide a stable environment for subsequent pile foundation construction. The burial depth and diameter of the outer casing need to be adjusted according to the depth and diameter of the pile to ensure that the outer casing can effectively protect the pile hole, prevent cave-ins, diameter expansion, and slurry leakage.

[0040] The outer casing includes a buried section and a protection section; the buried section is buried in the ground of the karst area; the protection section is exposed above the ground of the karst area; the protection section provides a construction space for the drill bit of the drilling rig. The height of the protection section is 50 - 100 cm.

[0041] S130. Use the drilling rig to carry out pile foundation construction based on the outer casing; wherein, the drilling rig is provided with a crawler-type mobile wheel set.

[0042] Align the drilling rig precisely with the designed position to ensure the verticality and accuracy of the borehole. Use the drilling rig to carry out pile foundation construction according to the designed depth and diameter. During the drilling process, pay attention to the construction techniques when passing through karst caves, such as repeatedly impacting with a small stroke of the impact drill and plugging with slurry filling when slurry leakage occurs. It should be noted that for the drill bit of the drilling rig used for pile foundation construction in karst areas, a higher flexibility is required. Therefore, the drill bit connected by the guide wheel set, support arm, and suspension rope of the present invention is used for construction. In addition, the mobile wheel set of the drilling rig should be set as a crawler structure.

[0043] Generally speaking, by conducting an investigation of the pile foundation data of the karst area to be constructed, obtaining the depth and diameter of the pile making, burying the outer casing to the preset pile bottom position on the karst ground, and using the drilling rig to carry out pile foundation construction according to the depth and diameter of the pile making, the problems of difficult hole formation and poor hole formation quality existing in traditional mechanical construction methods such as impact drills or rotary drills can be effectively avoided, and the construction efficiency and pile formation quality can be improved.

[0044] S140. After the pile foundation construction is completed, excavate the cap foundation pit and expose the pile head. Among them, excavating the cap foundation pit provides a working surface for the subsequent cap construction. Care should be taken during the foundation pit excavation to avoid damaging the pile foundation.

[0045] In a specific embodiment of the present invention, after the step of chiseling the pile head until the pile head steel bars are exposed, a pile head steel bar pretreatment step is further included; wherein, the pile head steel bar pretreatment includes grinding, straightening, and rust removal operations. Through the treatment of grinding and straightening the steel bars, it is convenient for the later installation of the bagged pile; by removing rust, the phenomenon of steel bar corrosion and oxidation is slowed down, thereby prolonging the service life of the steel bars. That is to say, by excavating the cap foundation pit, exposing the pile head, chiseling the pile head until the pile head steel bars are exposed, and lapping the pile head steel bars with the cap steel bars, the bearing capacity and structural stability of the pile foundation can be ensured, and the risk of uneven settlement, which affects the stability of the building, can be avoided.

[0046] S150. Chisel the pile head until the pile head steel bars are exposed, and lap the pile head steel bars with the cap steel bars.

[0047] S160. Pour a cushion layer at the bottom of the foundation pit of the bearing platform. The function of the cushion layer is to provide a solid and flat working surface for the construction of the bearing platform and has a certain function of preventing water drainage. After the cushion layer reaches the design strength, the binding of the steel bars of the subsequent bearing platform and the erection of the formwork can be carried out. It should be noted that the plain concrete cushion layer has excellent durability and wear resistance, can withstand high-intensity pressure and wear, and is not prone to breakage and cracks after long-term use. The material cost of the plain concrete cushion layer is relatively low, so the overall cost is relatively economical. Its color is natural, with a texture similar to that of stone, and it is beautiful and generous. The plain concrete cushion layer not only provides the beauty of the ground, but also has functions such as moisture-proof, mildew-proof, insect-proof, and dust-proof. In a specific embodiment of the present invention, the cushion layer adopts a C25 plain concrete cushion layer; the thickness of the cushion layer is 15-25 cm.

[0048] Generally speaking, by pouring a plain concrete cushion layer at the bottom of the foundation pit of the bearing platform, binding the lapped pile head steel bars and the bearing platform steel bars on the cushion layer, and pouring the bearing platform concrete, the connection reliability between the pile foundation and the bearing platform can be improved, and the stability of the overall structure can be enhanced.

[0049] S170. Bind the lapped pile head steel bars and the bearing platform steel bars on the cushion layer.

[0050] S180. Pour the bearing platform concrete by the spiral conveyor pump pouring method. Since the bearing platform is large in volume and heavy in mass, it belongs to mass concrete, so the prevention of cracks needs to be considered during concrete pouring. Use the spiral conveyor pump to transport the concrete from the mixer truck to the construction site and pour it through an adjustable spray port. This method of the spiral conveyor pump pouring method can realize continuous pouring of concrete and improve construction efficiency, but attention needs to be paid to the uniformity and fluidity of the concrete to avoid blockage or uneven pouring. After pouring is completed, curing is required to ensure that the concrete reaches the design strength.

[0051] The pile foundation construction drill and its construction method in the karst area of the present invention bury the outer casing at the preset pile bottom position of the karst ground to be constructed, then use the drill to carry out pile foundation construction based on the outer casing, and pour the cushion layer after the pile foundation construction is completed; through multiple measures such as the preset pile bottom, outer casing and cushion layer, it eliminates the potential hazard that the concrete pressure may cause the failure of the retaining structure and lead to concrete leakage or loss during the pile foundation concrete pouring process due to the existence of karst caves; on the premise of ensuring the quality control of the pile foundation construction in the karst area, by using the non-recoverable outer casing for pile foundation construction, the technical effects of shortening the construction period and reducing the construction cost are achieved. Through reasonable construction process arrangement and technical means, problems such as difficult hole formation, risk of hole collapse, slurry leakage, and sticking of the drill can be better solved, the construction efficiency and pile forming quality can be improved, and the bearing capacity and structural stability of the pile foundation can be ensured.

[0052] Embodiment 2

[0053] Figure 2 is a schematic structural diagram of a drilling rig for pile foundation construction in karst areas of the present invention. As Figure 2 shown, the present invention also protects a drilling rig for pile foundation construction in karst areas, which is applied to the pile foundation construction steps of the above-mentioned pile foundation construction method in karst areas; the drilling rig includes a drill bit 3, an operation platform 1 for providing power to the drill bit 3, a moving wheel set 2 arranged below the operation platform 1, and a support assembly for connecting the operation platform 1 and the drill bit 3; the support assembly includes a support arm 4, a suspension rope 7, a winch, a first guide pulley 5 and a second guide pulley 6; wherein, the support arm 4 is movably arranged on the operation platform 1, the first guide pulley 5 is arranged in the middle of the support arm 4, and the second guide pulley 6 is arranged at the top of the support arm 4; the suspension rope 7 is led out from the winch, successively bypasses the first guide pulley 5 and the second guide pulley 6, and is connected to the drill bit 3 at the end of the suspension rope 7; a slewing bearing is arranged between the operation platform 1 and the moving wheel set 2, and the moving wheel set 2 is of a crawler structure.

[0054] By adopting a crawler-type moving wheel set for the drilling rig of the present invention, it is suitable for the complex ground conditions in karst areas, and during use, the position of the drill bit can be accurately and flexibly adjusted according to actual needs through the support assembly, so that the drilling rig of the present invention is particularly suitable for karst areas. Among them, the operation platform is the main body of the drilling rig and plays a role of fixing and supporting the drilling rig. The moving wheel set is the moving module of the drilling rig, which facilitates the user to drive the device to a designated position at the construction site. The support assembly is used to install the drill bit on the operation platform and adjust the position of the drill bit according to actual needs, so that the device is suitable for different environments, further reflecting the practicality of the device. Among them, in order to make the drill bit more suitable for karst areas, the drill bit is a ground type drill bit; wherein, the upper and lower ends of the drill bit are set as frustum shapes; the middle section of the drill bit is cylindrical. Or rather, the drill bit can also adopt other existing structures in the art; including a drill bit body and a driving motor, which are used for the construction process of the pile foundation, and this means is common knowledge in the art and will not be specifically limited here. By arranging a slewing bearing between the operation platform 1 and the moving wheel set 2, a rotating structure is formed. The operation platform adjusts its angle under the action of the slewing bearing, so as to adjust the direction of the drill bit according to actual needs. The support arm 4 is movably connected to the operation platform 1 through an electric push rod and a movable bearing.

[0055] In a specific implementation process, the first guide wheel 5 can be installed on one side of the support arm 4; the second guide wheel 6 is installed on the top of the support arm 4; the lifting rope 7 is wound around the first guide wheel 5 and the second winding wheel 6 in sequence, and the end of the lifting rope 7 is connected to the top of the drill bit 3. A third guide wheel is provided at the connection between the end of the lifting rope and the drill bit, and the third guide wheel is a fixed pulley. The number of the third guide wheels is at least two. The movably arranged support arm 4, in combination with the design of the first guide wheel and the second guide wheel, facilitates the user to adjust the drill bit to a specified height through the lifting rope. The design of multiple fixed pulleys forms a fixed pulley system. The fixed pulley system can increase the effect of force by distributing multiple pulleys. In addition, the fixed pulley reduces friction through rolling friction, making it easier for the drill bit to move.

[0056] The process of pile foundation construction by the above-mentioned drilling rig for pile foundation construction in karst areas is as follows: First, the operator enters the interior of the operation platform 1, and under the action of the moving wheel set 2, moves the device to a specified position at the construction site. When the drilling rig moves to the specified position, the operator adjusts the direction of the operation platform 1 according to the environment and specific requirements of the construction site to ensure that the equipment is in the best working state. Next, the drill bit 3 is adjusted to a specified position through the movably arranged support arm 4 to ensure that the drill bit 3 is aligned with the accurate position of the pile foundation construction. After the position of the drill bit 3 is adjusted, the lifting rope 7 is slowly lowered through the first guide wheel 5 and the second guide wheel 6, and the drill bit 3 is adjusted to a specified height by using the lifting rope 7 to ensure that the drill bit 3 can accurately reach the designed pile bottom position. Finally, when the drill bit 3 is adjusted to the specified height, the drive source on the drill bit 3 is started to make the drill bit 3 rotate and start the pile foundation construction. During the drilling process, the drilling parameters are adjusted in a timely manner according to the geological conditions and construction requirements to ensure the stability and accuracy of the pile foundation construction. This device realizes flexible on-site movement through the moving wheel set, and the direction of the operation platform can be adjusted according to the construction site environment to ensure the adaptability and stability of the equipment. Through the movable design of the support arm, the drill bit can be accurately aligned with the construction position. By using the cooperation of the guide wheel and the lifting rope, the height of the drill bit can be accurately adjusted to ensure the accuracy of the construction. After starting the drive source of the drill bit, the drill bit rotates and drills to complete the pile foundation construction. The whole process is logically clear and easy to operate, which can effectively improve the construction efficiency and quality.

[0057] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to cover all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention. Any reference signs attached to the claims should not be regarded as limiting the claimed rights.

[0058] In addition, it is obvious that the term "comprising" does not exclude other units or steps, and the singular does not exclude the plural. A plurality of units or devices stated in the apparatus claims may also be implemented by one unit or device through software or hardware. The dust removal apparatus and method for a rolling mill according to the present invention have been described by way of example with reference to the accompanying drawings above.

Claims

1. A pile foundation construction method in karst areas, characterized in that, The method includes conducting a survey of pile foundation data for the karst area to be constructed to obtain the depth and diameter of pile making; burying an outer casing at the preset pile bottom position on the karst ground to be constructed according to the depth and diameter of the pile making; performing pile foundation construction using a drilling rig based on the outer casing; wherein, the drilling rig is provided with a crawler mobile wheel set; after the pile foundation construction is completed, excavating the pile cap foundation pit and exposing the pile head; chipping the pile head until the pile head steel bars are exposed, and lapping the pile head steel bars with the pile cap steel bars; pouring a cushion layer at the bottom of the pile cap foundation pit; tying the lapped pile head steel bars and pile cap steel bars on the cushion layer; performing pile cap concrete pouring by the screw conveyor pump pouring method.

2. The karst area pile foundation construction method according to claim 1, wherein the cushion layer is a C25 plain concrete cushion layer; the thickness of the cushion layer is 15 - 25 cm.

3. The pile foundation construction method in karst area according to claim 1, characterized in that, after the step of chipping the pile head until the pile head steel bars are exposed, a pile head steel bar pretreatment step is further included; wherein, the pile head steel bar pretreatment includes grinding, straightening and rust removal operations.

4. The pile foundation construction method in karst area according to claim 1, characterized in that, the outer casing includes a buried section and a protection section; the buried section is buried in the ground of the karst area; the protection section is exposed outside the ground of the karst area; the protection section provides a construction space for the drill bit of the drilling rig.

5. The pile foundation construction method in karst area according to claim 4, characterized in that, the height of the protection section is 50 - 100 cm.

6. A drilling rig for pile foundation construction in karst areas, characterized in that, applied to the pile foundation construction step of the karst area pile foundation construction method according to claim 1; the drilling rig includes a drill bit, an operation platform that provides power for the drill bit, a mobile wheel set arranged below the operation platform, and a support assembly for connecting the operation platform and the drill bit; the support assembly includes a support arm, a suspension rope, a winch, a first guide wheel and a second guide wheel; wherein, the support arm is movably arranged on the operation platform, the first guide wheel is arranged in the middle of the support arm, and the second guide wheel is arranged at the top of the support arm; the suspension rope is led out from the winch, sequentially bypasses the first guide wheel and the second guide wheel, and is connected to the drill bit at the end of the suspension rope; a slewing bearing is arranged between the operation platform and the mobile wheel set, and the mobile wheel set is of a crawler structure.

7. The drilling rig for pile foundation construction in karst areas according to claim 6, characterized in that, a third guide wheel is arranged at the connection between the end of the suspension rope and the drill bit, and the third guide wheel is a fixed pulley.

8. The drill for pile foundation construction in karst areas according to claim 7, characterized in that, the number of the third guide wheels arranged is at least two.

9. The drill for pile foundation construction in karst areas according to claim 6, wherein, the support arm is movably connected to the operation platform through an electric push rod and a movable bearing.

10. The drilling rig for pile foundation construction in karst areas according to claim 6, characterized in that, the drill bit is a ground type drill bit; wherein, the upper and lower ends of the drill bit are set as frustum shapes; the middle section of the drill bit is cylindrical.

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