Water and soil loss prevention rotary excavating pile construction method for karst cave dense area

Abstract

The invention discloses a rotary excavating pile construction method for a karst cave dense area capable of preventing water and soil loss. According to the real-time monitoring system, the sensor is installed on the drill bit, various data such as the drill bit position, the drilling speed and the hole wall stability in the drilling process are collected in real time, and real-time feedback is provided for construction. By means of the system, constructors can know the drilling state in time, drilling parameters are adjusted in real time through data analysis, and the drilling process is optimized. By means of real-time monitoring and adjusting, the construction efficiency is improved, risks caused by geological condition changes are greatly reduced, and the safety of the construction process and the drilling accuracy are guaranteed. According to the self-adaptive slurry injection system, the flow and pressure of slurry can be automatically adjusted according to real-time monitoring data, especially when a karst cave or an easily-collapsed hole section is encountered, the system can automatically increase the slurry injection amount so as to maintain the stability of a hole wall, the construction efficiency is improved, and the construction cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of rotary pile construction, and in particular relates to a rotary pile construction method in a karst cave-dense area to prevent soil loss. Background Art

[0002] With the rapid development of infrastructure construction, rotary pile construction technology has been widely used in various construction projects. However, when constructing rotary piles in areas with dense karst caves, traditional construction methods face many challenges, such as poor hole wall stability, high construction safety risks, and low construction efficiency. Existing technical means have certain limitations in dealing with these challenges, especially in preventing soil erosion and ensuring the quality of pile foundations.

[0003] Traditional drilling construction methods usually use a single-diameter drill bit to drill holes. This method is prone to accidents such as hole collapse and hole deviation when encountering caves or complex geological conditions, affecting construction safety and pile foundation quality. In addition, existing mud injection systems often rely on manual operation, making it difficult to accurately control the flow and pressure of the mud, and thus unable to effectively maintain the stability of the hole wall. Summary of the invention

[0004] The purpose of the present invention is to provide a method for constructing rotary piles in a cave-dense area to prevent soil loss in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: a method for constructing rotary piles in a cave-dense area to prevent soil erosion, the method comprising the following steps:

[0006] S1: Carry out preliminary investigation and preparation work, conduct geological survey of the construction area, understand the distribution, size, depth and groundwater flow of karst caves, collect relevant information, and formulate construction plans and safety measures;

[0007] S2: Clear weeds, debris and loose soil in the construction area. Level the site to ensure stable operation of construction equipment;

[0008] S3: Transport the rotary drilling rig, mud pump and excavator construction equipment to the site. Debug the equipment to ensure normal operation;

[0009] S4: Lay out a temporary drainage system and set up drainage ditches around the construction area to prevent rainwater and groundwater from flowing into the construction area. Install a temporary drainage pump to ensure smooth drainage;

[0010] S5: Position the construction piles. According to the design drawings, use the total station measuring equipment to accurately position the piles. Mark the piles to ensure the pile positions are accurate.

[0011] S6: Conduct multi-stage drilling construction, set up a real-time monitoring system and an adaptive mud injection system, and introduce air lift reverse circulation technology to inject compressed air into the hole to form a gas-liquid two-phase flow, effectively remove the sediment at the bottom of the hole and improve the hole cleaning efficiency;

[0012] S7: After drilling, use a boremeter to check the hole diameter and hole shape to ensure that they meet the design requirements. Trim unqualified holes until they are qualified;

[0013] S8: Use a mud pump to pump out the mud in the hole and remove the sediment at the bottom of the hole. Ensure that the thickness of the sediment at the bottom of the hole is less than the specification requirements;

[0014] S9: Make the steel cage according to the design requirements. Use a crane to lift the steel cage into the hole and ensure that the position of the steel cage is accurate;

[0015] S10: Use the conduit method to pour concrete to ensure that the concrete fills the entire pile hole. During the concrete pouring process, strictly control the pouring speed and height;

[0016] S11: After the concrete pouring is completed, the pile body is inspected for quality to ensure that it meets the design requirements. The piles are maintained and accepted after the strength reaches the design requirements. After the construction is completed, the temporary drainage system is dismantled and the landform is restored.

[0017] In a preferred embodiment, in step S1, geological survey shall be conducted by using geological radar and geophysical exploration technology, the survey range shall cover at least 500 meters around the construction area, and the survey depth shall be at least twice the design depth of the pile foundation, i.e. if the design depth of the pile foundation is 30 meters, the survey depth shall be at least 60 meters. The survey report shall include the distribution, size, depth, groundwater flow rate and chemical composition analysis of the caves.

[0018] In a preferred embodiment, in step S2, the ground slope should be controlled within 1%, and for large equipment operation areas, the slope should be controlled within 0.5%. When removing weeds and debris, the thickness of the loose soil layer shall not exceed 0.5 meters, and compaction is required, and the compaction degree should reach more than 90%.

[0019] In step S3, the commissioning of the construction equipment should include that the verticality deviation of the drill pipe of the rotary drilling rig does not exceed 0.5%, the pressure of the mud pump should be within the range of 1.5-3.0MPa, and the flow rate should be within the range of 200-400L / min. The bucket capacity of the excavator should be selected according to the earthwork volume. For a small excavator, the bucket capacity is 0.5 cubic meters.

[0020] In a preferred embodiment, in step S4, the drainage ditch of the temporary drainage system should be designed to withstand a rainfall of 50 mm within 24 hours, and the depth of the drainage ditch should be 0.6 m and the width should be 0.4 m. The drainage capacity of the temporary drainage pump should be at least 150 cubic meters per hour, and a backup pump should be provided.

[0021] In step S5, when the construction pile position is located, the accuracy of the total station should reach ±2 mm. The pile position mark should be made of a material that is not easy to fade, and the mark diameter should not be less than 0.2 meters.

[0022] In a preferred embodiment, in step S6, the multi-stage drilling construction specifically includes:

[0023] Phase 1: Initial exploratory drilling

[0024] Equipment preparation: Select a suitable rotary drilling rig and install a small diameter drill bit. Ensure that the mud pump and mud circulation system are working properly.

[0025] Drilling operation: Start the rotary drilling rig and start preliminary drilling at the set drilling speed. During the drilling process, the hole conditions are monitored in real time, including the stability of the hole wall and the mud return conditions.

[0026] Cave detection: When drilling reaches the designed depth or encounters an abnormal situation, stop drilling. Use the sensor carried by the drill bit or the in-hole TV camera system to detect the specific location and size of the cave.

[0027] Data recording: record the location, size, and shape data of the cave to provide reference for subsequent construction.

[0028] Phase 2: Main drilling operations

[0029] Replace drill bit: After the cave is detected and corresponding measures are taken, the small diameter drill bit is removed and replaced with a large diameter drill bit to prepare for the main drilling operation.

[0030] Adjust drilling parameters: adjust drilling speed, mud flow and pressure parameters according to geological conditions and design requirements.

[0031] Continue drilling: Start drilling with new parameters to ensure that the hole wall is stable and avoid hole collapse. During the drilling process, regularly check the hole diameter and verticality to ensure the quality of the drilling.

[0032] Hole cleaning: After drilling to the designed depth, hole cleaning is performed to ensure that the thickness of the sediment at the bottom of the hole meets the design requirements;

[0033] The small diameter drill bit should be 150-250mm in diameter, and diamond drill bit or carbide drill bit should be selected to adapt to different geological conditions. When the small diameter drill bit is used for preliminary detection, the drilling speed should not be too fast, and is generally controlled at 0.5-1.0 m / min.

[0034] The diameter of the large diameter drill bit is 600-1200mm. The large diameter drill bit uses a spiral drill bit or an impact drill bit to adapt to different geological conditions. The drilling speed of the large diameter drill bit is controlled at 1.0-2.0 meters per minute.

[0035] In a preferred embodiment, in step S6, the real-time monitoring system includes:

[0036] A.Sensor module:

[0037] Drill position sensor: Use GPS or gyro sensors to accurately measure the three-dimensional position of the drill head.

[0038] Drilling speed sensor: Monitor the rotation speed and feed speed of the drill bit through an encoder or speed sensor.

[0039] Hole wall stability sensor: including hole wall pressure sensor and hole wall displacement sensor, used to monitor the stability state of the hole wall.

[0040] B. Data acquisition and transmission module:

[0041] Data acquisition unit: converts the analog signals collected by the sensor into digital signals and performs preliminary processing.

[0042] Wireless transmission device: Use wireless communication technology to transmit data to the ground monitoring center in real time.

[0043] C. Data processing and analysis module:

[0044] Central processing unit: receives and processes data from the data acquisition unit and performs real-time analysis.

[0045] Data analysis software: used to analyze drilling data, including data visualization, trend analysis, and anomaly detection.

[0046] D. Control and adjustment module:

[0047] Parameter adjustment unit: Automatically or manually adjust drilling parameters, drill speed, feed speed, and mud flow rate according to data analysis results.

[0048] Alarm system: When abnormal data is detected, an alarm is triggered to notify the operator to take appropriate measures.

[0049] The data collected by the sensor module is transmitted to the data acquisition unit via wired or wireless means.

[0050] The data acquisition unit encodes and preliminarily processes the sensor data to ensure the accuracy and integrity of the data.

[0051] The processed data is sent to the central processing unit in real time via a wireless transmission device.

[0052] The central processing unit uses data analysis software to conduct in-depth analysis of the data and extract useful information.

[0053] The data analysis results are transmitted to the parameter adjustment unit to guide the adjustment of drilling parameters.

[0054] If the data analysis software detects a potential risk, it notifies the operator through an alarm system and recommends or automatically executes appropriate adjustment measures.

[0055] The parameter adjustment unit sends the adjustment instructions to the drilling rig control system to achieve real-time control of the drilling process.

[0056] The interaction between the alarm system and the operator ensures that timely measures can be taken in emergency situations.

[0057] In a preferred embodiment, in step S6, the adaptive mud injection system collects data in the drilling process in real time through sensors installed on the drill bit and the hole wall. The collected data is transmitted to the central processing unit and processed and analyzed using data analysis software. According to the analysis results, the system automatically adjusts the flow rate and pressure of the mud pump;

[0058] The formula for calculating the mud demand is: Q = K × A × H × (1 + Δ);

[0059] in:

[0060] Q is the required mud flow rate (L / min). K is the flow coefficient, which is determined according to geological conditions and borehole diameter. A is the cross-sectional area of ​​the borehole (m 2 ). H is the drilling depth (m). Δ is the safety factor used to consider the additional mud demand.

[0061] The mud pressure adjustment calculation formula is: Padjust = Pbase + ΔP; where Padjust is the adjusted mud pressure (bar). Pbase is the base mud pressure, which is preset according to geological conditions and drilling depth. ΔP is the pressure adjustment amount (bar).

[0062] In a preferred embodiment, in step S7, when the aperture and hole shape are checked using a porosimeter, the allowable deviation of the aperture should be ±50 mm, and the deviation of the hole shape should not exceed 1% of the designed aperture. When trimming unqualified holes, a special drill bit or brush should be used to trim the hole wall, and the deviation of the trimmed aperture should not exceed ±20 mm.

[0063] In a preferred embodiment, in step S8, when the mud in the hole is pumped out, the flow rate of the mud pump should be at least 300 cubic meters per hour, and the thickness of the sediment at the bottom of the hole should be less than 50 mm. The slurry pumping operation should be completed within 1 hour before concrete pouring.

[0064] In a preferred embodiment, in step S9, when making the steel cage, the diameter of the steel bar is 25 mm, the spacing is 200 mm, and the welding length should not be less than 8 times the diameter of the steel bar. When hoisting the steel cage, the tonnage of the crane used should be at least 25 tons to ensure smooth hoisting;

[0065] In the step S10, when pouring concrete, the conduit method should ensure that the free fall height of the concrete does not exceed 2 meters, the pouring speed of the concrete should be controlled at 2-4 cubic meters per minute, and the slump should be between 180-220 mm.

[0066] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0067] 1. In the present invention, the multi-stage drilling construction uses a small-diameter drill bit for preliminary detection first, and then replaces it with a large-diameter drill bit for the main drilling operation, which effectively improves the safety and efficiency of the construction. This method can accurately detect the specific location and size of the cave, avoid the risk of cave collapse encountered by direct large-diameter drilling, and reduce the uncertainty and potential safety hazards in construction. At the same time, this phased construction method can also better control the drilling quality, ensure the stability and bearing capacity of the pile foundation, thereby improving the quality of the entire pile foundation project.

[0068] 2. In the present invention, the real-time monitoring system collects various data in the drilling process, such as drill bit position, drilling speed, hole wall stability, etc., in real time by installing sensors on the drill bit, providing real-time feedback for construction. This system enables construction personnel to understand the drilling status in a timely manner, adjust drilling parameters in real time through data analysis, and optimize the drilling process. Such real-time monitoring and adjustment not only improves construction efficiency, but also greatly reduces the risks caused by changes in geological conditions, ensuring the safety of the construction process and the accuracy of drilling. The adaptive mud injection system can automatically adjust the flow and pressure of the mud according to the real-time monitoring data, especially when encountering caves or easy-to-collapse hole sections, the system will automatically increase the amount of mud injection to maintain the stability of the hole wall. The application of this system significantly improves the control level of hole wall stability during drilling and reduces construction accidents caused by unstable hole walls. At the same time, automated mud injection reduces manual intervention, improves construction efficiency, and reduces construction costs.

[0069] 3. In the present invention, the air lift reverse circulation technology effectively extracts the sediment and waste mud at the bottom of the hole out of the hole by forming a negative pressure in the borehole, thereby improving the efficiency and quality of hole cleaning. This technology not only reduces the thickness of the sediment at the bottom of the hole and ensures the quality of concrete pouring, but also shortens the construction period due to its efficient hole cleaning ability. In addition, the air lift reverse circulation technology can also reduce the impact of mud on the environment because it reduces the amount of mud used and processed, which is beneficial to environmental protection and construction sustainability. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0071] Example:

[0072] A method for constructing rotary excavation piles in a cave-dense area to prevent soil erosion, the method comprising the following steps:

[0073] S1: Carry out preliminary investigation and preparation work, conduct geological survey of the construction area, understand the distribution, size, depth and groundwater flow of karst caves, collect relevant information, and formulate construction plans and safety measures;

[0074] S2: Clear weeds, debris and loose soil in the construction area. Level the site to ensure stable operation of construction equipment;

[0075] S3: Transport construction equipment such as rotary drilling rigs, mud pumps, excavators, etc. to the site. Debug the equipment to ensure normal operation;

[0076] S4: Lay out a temporary drainage system and set up drainage ditches around the construction area to prevent rainwater and groundwater from flowing into the construction area. Install a temporary drainage pump to ensure smooth drainage;

[0077] S5: Position the construction piles. According to the design drawings, use total stations and other measuring equipment to accurately position the piles. Mark the piles to ensure that the piles are positioned accurately.

[0078] S6: Conduct multi-stage drilling construction, set up a real-time monitoring system and an adaptive mud injection system, and introduce air lift reverse circulation technology to inject compressed air into the hole to form a gas-liquid two-phase flow, effectively remove the sediment at the bottom of the hole and improve the hole cleaning efficiency;

[0079] S7: After drilling, use a boremeter to check the hole diameter and hole shape to ensure that they meet the design requirements. Trim unqualified holes until they are qualified;

[0080] S8: Use a mud pump to pump out the mud in the hole and remove the sediment at the bottom of the hole. Ensure that the thickness of the sediment at the bottom of the hole is less than the specification requirements;

[0081] S9: Make the steel cage according to the design requirements. Use a crane to lift the steel cage into the hole and ensure that the position of the steel cage is accurate;

[0082] S10: Use the conduit method to pour concrete to ensure that the concrete fills the entire pile hole. During the concrete pouring process, strictly control the pouring speed and height;

[0083] S11: After the concrete pouring is completed, the pile body is inspected for quality to ensure that it meets the design requirements. The piles are maintained and accepted after the strength reaches the design requirements. After the construction is completed, the temporary drainage system is dismantled and the landform is restored.

[0084] In step S1, geological survey shall use geological radar, geophysical exploration and other technologies, the survey range shall cover at least 500 meters around the construction area, and the survey depth shall be at least twice the design depth of the pile foundation, that is, if the design depth of the pile foundation is 30 meters, the survey depth shall be at least 60 meters. The survey report shall include the distribution, size, depth, groundwater flow rate (the flow rate shall not exceed 0.5 m / s) of the caves and the chemical composition analysis of the groundwater.

[0085] In step S2, the ground slope should be controlled within 1%, and for large equipment operation areas, the slope should be controlled within 0.5%. When removing weeds and debris, the thickness of the loose soil layer shall not exceed 0.5 meters, and compaction is required, and the compaction degree should reach more than 90%.

[0086] In step S3, the commissioning of the construction equipment should include that the verticality deviation of the drill pipe of the rotary drilling rig does not exceed 0.5%, the pressure of the mud pump should be within the range of 1.5-3.0MPa, and the flow rate should be within the range of 200-400L / min. The bucket capacity of the excavator should be selected according to the earthwork volume. For a small excavator, the bucket capacity is 0.5 cubic meters.

[0087] In step S4, the drainage ditch of the temporary drainage system should be designed to withstand a rainfall of 50 mm within 24 hours, with a depth of 0.6 m and a width of 0.4 m. The drainage capacity of the temporary drainage pump should be at least 150 cubic meters per hour, and a backup pump should be provided.

[0088] In step S5, when the construction pile position is located, the accuracy of the total station should reach ±2 mm. The pile position mark should use a material that is not easy to fade, such as paint or a special pile position marking nail, and the marking diameter should not be less than 0.2 meters.

[0089] In step S6, the multi-stage drilling construction specifically includes:

[0090] Phase 1: Initial exploratory drilling

[0091] Equipment preparation: Select a suitable rotary drilling rig and install a small diameter drill bit. Ensure that the mud pump and mud circulation system are working properly.

[0092] Drilling operation: Start the rotary drilling rig and start preliminary drilling at the set drilling speed. During the drilling process, the hole conditions are monitored in real time, including hole wall stability, mud return conditions, etc.

[0093] Cave detection: When drilling reaches the designed depth or encounters an abnormal situation, stop drilling. Use the sensor carried by the drill bit or the in-hole TV camera system to detect the specific location and size of the cave.

[0094] Data recording: record the location, size, shape and other data of the cave to provide reference for subsequent construction.

[0095] Phase 2: Main drilling operations

[0096] Replace the drill bit: After the cave is detected and corresponding measures are taken (such as filling, reinforcement, etc.), the small-diameter drill bit is removed and replaced with a large-diameter drill bit to prepare for the main drilling operation.

[0097] Adjust drilling parameters: adjust drilling speed, mud flow and pressure and other parameters according to geological conditions and design requirements.

[0098] Continue drilling: Start drilling with new parameters to ensure that the hole wall is stable and avoid hole collapse. During the drilling process, regularly check the hole diameter and verticality to ensure the quality of the drilling.

[0099] Hole cleaning: After drilling to the designed depth, hole cleaning is performed to ensure that the thickness of the sediment at the bottom of the hole meets the design requirements;

[0100] The small diameter drill bit should be 150-250mm in diameter, and diamond drill bit or carbide drill bit should be selected to adapt to different geological conditions. When the small diameter drill bit is used for preliminary detection, the drilling speed should not be too fast, and is generally controlled at 0.5-1.0 m / min.

[0101] The diameter of the large diameter drill bit is 600-1200mm. The large diameter drill bit uses a spiral drill bit or an impact drill bit to adapt to different geological conditions. The drilling speed of the large diameter drill bit is controlled at 1.0-2.0 m / min

[0102] In step S6, the real-time monitoring system includes:

[0103] A.Sensor module:

[0104] Drill position sensor: Usually uses GPS or gyro sensor to accurately measure the three-dimensional position of the drill head.

[0105] Drilling speed sensor: Monitor the rotation speed and feed speed of the drill bit through an encoder or speed sensor.

[0106] Hole wall stability sensor: including hole wall pressure sensor, hole wall displacement sensor, etc., used to monitor the stability state of the hole wall.

[0107] Other sensors: such as temperature sensors, humidity sensors, mud property sensors, etc., are used to monitor the drilling environment.

[0108] B. Data acquisition and transmission module:

[0109] Data acquisition unit: converts the analog signals collected by the sensor into digital signals and performs preliminary processing.

[0110] Wireless transmission device: Use wireless communication technology (such as Wi-Fi, Bluetooth, 4G / 5G networks, etc.) to transmit data to the ground monitoring center in real time.

[0111] C. Data processing and analysis module:

[0112] Central processing unit: receives and processes data from the data acquisition unit and performs real-time analysis.

[0113] Data analysis software: used to analyze drilling data, including data visualization, trend analysis, anomaly detection, etc.

[0114] D. Control and adjustment module:

[0115] Parameter adjustment unit: Automatically or manually adjust drilling parameters such as drill speed, feed speed, mud flow, etc. according to data analysis results.

[0116] Alarm system: When abnormal data is detected, an alarm is triggered to notify the operator to take appropriate measures.

[0117] The data collected by the sensor module is transmitted to the data acquisition unit via wired or wireless means.

[0118] The data acquisition unit encodes and preliminarily processes the sensor data to ensure the accuracy and integrity of the data.

[0119] The processed data is sent to the central processing unit in real time via a wireless transmission device.

[0120] The central processing unit uses data analysis software to conduct in-depth analysis of the data and extract useful information.

[0121] The data analysis results are transmitted to the parameter adjustment unit to guide the adjustment of drilling parameters.

[0122] If the data analysis software detects a potential risk, it notifies the operator through an alarm system and recommends or automatically executes appropriate adjustment measures.

[0123] The parameter adjustment unit sends the adjustment instructions to the drilling rig control system to achieve real-time control of the drilling process.

[0124] The interaction between the alarm system and the operator ensures that timely measures can be taken in emergency situations.

[0125] In step S6, the adaptive mud injection system collects data in real time during the drilling process through sensors installed on the drill bit and the hole wall. The collected data is transmitted to the central processing unit and processed and analyzed using data analysis software. Based on the analysis results, the system automatically adjusts the flow and pressure of the mud pump;

[0126] The formula for calculating the mud demand is: Q = K × A × H × (1 + Δ);

[0127] in:

[0128] Q is the required mud flow rate (L / min). K is the flow coefficient, which is determined according to geological conditions and borehole diameter. A is the cross-sectional area of ​​the borehole (m 2 ). H is the drilling depth (m). Δ is the safety factor used to consider the additional mud demand.

[0129] The mud pressure adjustment calculation formula is: Padjust = Pbase + ΔP; where Padjust is the adjusted mud pressure (bar). Pbase is the base mud pressure, which is preset according to geological conditions and drilling depth. ΔP is the pressure adjustment amount (bar).

[0130] In step S7, when the aperture and hole shape are checked using a pore gauge, the allowable deviation of the aperture should be ±50 mm, and the deviation of the hole shape should not exceed 1% of the designed aperture. When trimming unqualified holes, a special drill or brush should be used to trim the hole wall, and the deviation of the trimmed aperture should not exceed ±20 mm.

[0131] In step S8, when the mud in the hole is pumped out, the flow rate of the mud pump should be at least 300 cubic meters per hour, and the thickness of the sediment at the bottom of the hole should be less than 50 mm. The slurry pumping operation should be completed within 1 hour before concrete pouring.

[0132] In step S9, when making the steel cage, the diameter of the steel bar is 25 mm, the spacing is 200 mm, and the welding length should not be less than 8 times the diameter of the steel bar. When hoisting the steel cage, the tonnage of the crane used should be at least 25 tons to ensure smooth hoisting;

[0133] In step S10, when pouring concrete, the conduit method should ensure that the free fall height of the concrete does not exceed 2 meters, the pouring speed of the concrete should be controlled at 2-4 cubic meters per minute, and the slump should be between 180-220 mm.

[0134] In the present invention, the multi-stage drilling construction uses a small-diameter drill bit for preliminary detection first, and then replaces it with a large-diameter drill bit for the main drilling operation, which effectively improves the safety and efficiency of the construction. This method can accurately detect the specific location and size of the cave, avoid the risk of cave collapse encountered by direct large-diameter drilling, and reduce the uncertainty and potential safety hazards in the construction. At the same time, this staged construction method can also better control the drilling quality, ensure the stability and bearing capacity of the pile foundation, thereby improving the quality of the entire pile foundation project.

[0135] In the present invention, the real-time monitoring system collects various data in the drilling process, such as drill bit position, drilling speed, hole wall stability, etc., in real time by installing sensors on the drill bit, providing real-time feedback for construction. This system enables construction personnel to understand the drilling status in time, adjust drilling parameters in real time through data analysis, and optimize the drilling process. Such real-time monitoring and adjustment not only improves construction efficiency, but also greatly reduces the risks caused by changes in geological conditions, ensuring the safety of the construction process and the accuracy of drilling. The adaptive mud injection system can automatically adjust the flow and pressure of the mud according to the real-time monitoring data, especially when encountering a cave or a hole section that is prone to collapse, the system will automatically increase the amount of mud injection to maintain the stability of the hole wall. The application of this system significantly improves the control level of the hole wall stability during the drilling process and reduces construction accidents caused by the instability of the hole wall. At the same time, automated mud injection reduces manual intervention, improves construction efficiency, and reduces construction costs.

[0136] In the present invention, the air lift reverse circulation technology effectively extracts the sediment and waste mud at the bottom of the hole out of the hole by forming a negative pressure in the borehole, thereby improving the efficiency and quality of hole cleaning. This technology not only reduces the thickness of the sediment at the bottom of the hole and ensures the quality of concrete pouring, but also shortens the construction period due to its efficient hole cleaning ability. In addition, the air lift reverse circulation technology can also reduce the impact of mud on the environment because it reduces the amount of mud used and processed, which is beneficial to environmental protection and construction sustainability.

[0137] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0138] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing rotary piles in a cave-dense area to prevent soil erosion. Features: The method comprises the following steps: S1: Carry out preliminary investigation and preparation work, conduct geological survey of the construction area, understand the distribution, size, depth and groundwater flow of karst caves, collect relevant information, and formulate construction plans and safety measures; S2: Clear weeds, debris and loose soil in the construction area; level the site to ensure stable operation of construction equipment; S3: Transport the rotary drilling rig, mud pump and excavator construction equipment to the site; debug the equipment to ensure normal operation of the equipment; S4: Lay out a temporary drainage system and set up drainage ditches around the construction area to prevent rainwater and groundwater from flowing into the construction area; install temporary drainage pumps to ensure smooth drainage; S5: Position the construction piles. According to the design drawings, use the total station measuring equipment to accurately position the piles. Mark the piles to ensure the piles are accurate. S6: Conduct multi-stage drilling construction, set up a real-time monitoring system and an adaptive mud injection system, and introduce air lift reverse circulation technology to inject compressed air into the hole to form a gas-liquid two-phase flow, effectively remove the sediment at the bottom of the hole and improve the hole cleaning efficiency; S7: After drilling is completed, use a boremeter to check the hole diameter and hole shape to ensure that they meet the design requirements; trim unqualified holes until they are qualified; S8: Use a mud pump to pump out the mud in the hole and remove the sediment at the bottom of the hole; ensure that the thickness of the sediment at the bottom of the hole is less than the specification requirements; S9: Make the steel cage according to the design requirements; use a crane to lift the steel cage into the hole to ensure the correct position of the steel cage; S10: Use the conduit method to pour concrete to ensure that the concrete fills the entire pile hole; during the concrete pouring process, strictly control the pouring speed and height; S11: After the concrete pouring is completed, the pile body is inspected for quality to ensure that it meets the design requirements. The piles are maintained and accepted after the strength reaches the design requirements. After the construction is completed, the temporary drainage system is dismantled and the landform is restored.

2. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In step S1, geological survey shall use geological radar and geophysical exploration technology, the survey range shall cover at least 500 meters around the construction area, and the survey depth shall be at least twice the design depth of the pile foundation, that is, if the design depth of the pile foundation is 30 meters, the survey depth shall be at least 60 meters; the survey report shall include the distribution, size, depth, groundwater flow rate and chemical composition analysis of the caves.

3. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In step S2, the ground slope should be controlled within 1%, and for large equipment operation areas, the slope should be controlled within 0.5%; when removing weeds and debris, the thickness of the loose soil layer shall not exceed 0.5 meters, and compaction is required, and the compaction degree should reach more than 90%; In step S3, the debugging of the construction equipment should include that the verticality deviation of the drill pipe of the rotary drilling rig should not exceed 0.5%, the pressure of the mud pump should be within the range of 1.5-3.0MPa, and the flow rate should be within the range of 200-400L / min; the bucket capacity of the excavator should be selected according to the amount of earthwork, and for a small excavator, the bucket capacity is 0.5 cubic meters.

4. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In step S4, the drainage ditch of the temporary drainage system should be designed to withstand a rainfall of 50 mm within 24 hours, and the depth of the drainage ditch should be 0.6 m and the width should be 0.4 m; the drainage capacity of the temporary drainage pump should be at least 150 cubic meters per hour, and a backup pump should be provided; In step S5, when locating the construction pile position, the accuracy of the total station should reach ±2 mm; the pile position mark should use a material that is not easy to fade, and the mark diameter should not be less than 0.2 meters.

5. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In step S6, the multi-stage drilling construction specifically includes: Phase 1: Initial exploratory drilling Equipment preparation: select a suitable rotary drilling rig and install a small diameter drill bit; ensure that the mud pump and mud circulation system are working properly; Drilling operation: Start the rotary drilling rig and start preliminary drilling at the set drilling speed; during the drilling process, monitor the situation in the hole in real time, including the stability of the hole wall and the mud return situation; Cave detection: When drilling reaches the designed depth or encounters an abnormal situation, stop drilling; use the sensor carried by the drill bit or the in-hole TV camera system to detect the specific location and size of the cave; Data recording: record the location, size, and shape of the cave to provide reference for subsequent construction; Phase 2: Main drilling operations Replace the drill bit: After detecting the cave and taking corresponding measures, withdraw the small-diameter drill bit; replace it with a large-diameter drill bit and prepare for the main drilling operation; Adjust drilling parameters: adjust drilling speed, mud flow and pressure parameters according to geological conditions and design requirements; Continue drilling: Start drilling with new parameters to ensure that the hole wall is stable and avoid hole collapse; during the drilling process, regularly check the hole diameter and verticality to ensure the quality of the drilling; Hole cleaning: After drilling to the designed depth, hole cleaning is performed to ensure that the thickness of the sediment at the bottom of the hole meets the design requirements; The small diameter drill bit should be 150-250mm in diameter, and diamond drill bit or carbide drill bit should be selected to adapt to different geological conditions. When the small diameter drill bit is used for preliminary detection, the drilling speed should not be too fast, and it is generally controlled at 0.5-1.0 m / min. The diameter of the large diameter drill bit is 600-1200mm; the large diameter drill bit uses a spiral drill bit or an impact drill bit to adapt to different geological conditions; the drilling speed of the large diameter drill bit is controlled at 1.0-2.0 m / min.

6. A method for constructing rotary piles in a cave-dense area to prevent soil loss as claimed in claim 1, Features: In step S6, the real-time monitoring system includes: A.Sensor module: Drill position sensor: Use GPS or gyro sensor to accurately measure the three-dimensional position of the drill bit; Drilling speed sensor: monitors the rotation speed and feed speed of the drill bit through an encoder or speed sensor; Hole wall stability sensor: including hole wall pressure sensor and hole wall displacement sensor, used to monitor the stability of the hole wall; B. Data acquisition and transmission module: Data acquisition unit: converts the analog signals collected by the sensor into digital signals and performs preliminary processing; Wireless transmission device: uses wireless communication technology to transmit data to the ground monitoring center in real time; C. Data processing and analysis module: Central processing unit: receives and processes data from the data acquisition unit and performs real-time analysis; Data analysis software: used to analyze drilling data, including data visualization, trend analysis, and anomaly detection; D. Control and adjustment module: Parameter adjustment unit: automatically or manually adjust drilling parameters, drill speed, feed speed, and mud flow rate according to data analysis results; Alarm system: When abnormal data is detected, an alarm is triggered to notify the operator to take appropriate measures; The data collected by the sensor module is transmitted to the data acquisition unit via wired or wireless means; The data acquisition unit encodes and preliminarily processes the sensor data to ensure the accuracy and integrity of the data; The processed data is sent to the central processing unit in real time via a wireless transmission device; The central processing unit uses data analysis software to conduct in-depth analysis of the data and extract useful information; The data analysis results are transmitted to the parameter adjustment unit to guide the adjustment of drilling parameters; If the data analysis software detects a potential risk, it will notify the operator through an alarm system and recommend or automatically execute appropriate adjustment measures; The parameter adjustment unit sends the adjustment instructions to the drilling rig control system to achieve real-time control of the drilling process; The interaction between the alarm system and the operator ensures that timely measures can be taken in emergency situations.

7. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In step S6, the adaptive mud injection system collects data in the drilling process in real time through sensors installed on the drill bit and the hole wall; transmits the collected data to the central processing unit, and uses data analysis software to process and analyze it; according to the analysis results, the system automatically adjusts the flow rate and pressure of the mud pump; The formula for calculating the mud demand is: Q = K × A × H × (1 + Δ); in: Q is the required mud flow rate (L / min); K is the flow coefficient, which is determined according to geological conditions and borehole diameter; A is the cross-sectional area of ​​the borehole (m 2 ); H is the drilling depth (m); Δ is the safety factor used to consider the additional mud demand; The mud pressure adjustment calculation formula is: Padjust = Pbase + ΔP; where Padjust is the adjusted mud pressure (bar); Pbase is the baseline mud pressure, which is preset according to geological conditions and drilling depth; ΔP is the pressure adjustment amount (bar).

8. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In step S7, when the aperture and hole shape are checked using a porosimeter, the allowable deviation of the aperture should be ±50 mm, and the deviation of the hole shape should not exceed 1% of the designed aperture; when trimming unqualified holes, a special drill bit or brush should be used to trim the hole wall, and the aperture deviation after trimming should not exceed ±20 mm.

9. A method for constructing rotary piles in a cave-dense area to prevent soil loss as claimed in claim 1, Features: In step S8, when the mud in the hole is pumped out, the flow rate of the mud pump should be at least 300 cubic meters per hour, and the thickness of the sediment at the bottom of the hole should be less than 50 mm; the slurry pumping operation should be completed within 1 hour before concrete pouring.

10. A method for constructing rotary piles in a cave-dense area to prevent soil erosion as claimed in claim 1, Features: In the step S9, when making the steel cage, the diameter of the steel bar is 25 mm, the spacing is 200 mm, and the welding length should not be less than 8 times the diameter of the steel bar; when hoisting the steel cage, the tonnage of the crane used should be at least 25 tons to ensure smooth hoisting; In the step S10, when pouring concrete, the conduit method should ensure that the free fall height of the concrete does not exceed 2 meters, the pouring speed of the concrete should be controlled at 2-4 cubic meters per minute, and the slump should be between 180-220 mm.