A real-time monitoring method for offshore gravel pile construction

Abstract

The present invention discloses a real-time monitoring method for the construction of offshore gravel piles, which is based on a PLC monitoring system. The PLC monitoring system includes a GPS positioning system, a radar rangefinder, a weighing sensor, an encoder, and a main controller. The real-time monitoring method for the construction of offshore gravel piles according to the present invention comprises the following steps: Step 1, input various parameters of the gravel pile into the display screen of the main controller first; Step 2, when the pile pipe is vibrated and inserted into the soil layer to a certain depth, add two measuring hoppers of gravel into the pile pipe; Step 3, continue to vibrate and insert the pile pipe to the designed bottom elevation under the pressure-maintaining state; Step 4, perform end treatment; Step 5, lift the pile pipe. When the height of the gravel in the pile pipe is less than 3 - 5 m, immediately stop lifting the pile pipe and add the remaining gravel into the pile pipe, and then lift the pile pipe; Step 6, compare the bottom elevation of the pile pipe with the designed pile top elevation of the gravel pile to determine whether to back-drive the pile pipe. The present invention can effectively control the pile-forming quality of the gravel pile.

Description

Technical Field

[0001] The present invention relates to a real-time monitoring method for the construction of offshore gravel piles. Background Art

[0002] A gravel pile is a composite foundation reinforcement pile mainly made of gravel (pebble). Gravel piles and sand piles are collectively referred to as granular piles or coarse-grained soil piles abroad. The so-called granular pile refers to a pile without cohesive strength. A composite foundation composed of granular piles such as gravel columns or gravel piles and the soil between the piles can also be called a granular pile composite foundation. Gravel piles, sand piles, muck piles and other composite foundations widely used at home and abroad are all granular pile composite foundations.

[0003] The quality of vibroflotation gravel piles should mainly be based on the principle of full compaction of the pile body, which is closely related to the progress of hole formation, the amount of filling material, and the vibration retention time. Only under a certain amount of filling material can a certain compacting current be achieved. A certain vibration retention time is also required to vibrate and compact the filling material into a pile.

[0004] The existing construction of vibroflotation gravel piles mainly relies on manual judgment by operators. Due to the differences in operators' experience, proficiency, and operation skills, there is a lack of a scientific quantitative evaluation standard for the quality of formed piles. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a real-time monitoring method for the construction of offshore gravel piles, which can correctly guide the construction of gravel piles and effectively control the quality of formed gravel piles.

[0006] The purpose of the present invention is achieved as follows: A real-time monitoring method for the construction of offshore gravel piles, based on a PLC monitoring system, the PLC monitoring system includes a GPS positioning system, a radar rangefinder, a weighing sensor, an encoder, and a main controller;

[0007] The GPS positioning system is arranged on the top of the cab of the gravel pile construction ship. The GPS positioning system is used to determine the position, direction, and attitude of the gravel pile construction ship in the engineering coordinate system, so as to determine the position of the gravel pile;

[0008] The radar rangefinder is arranged in the feed hopper on the top of the pile pipe. The radar rangefinder is used to measure the height of the material level in the pile pipe in real time;

[0009] The weighing sensor is arranged below the metering hopper of the gravel pile construction ship; the weighing sensor is used to measure the weight of the gravel material added into the pile pipe each time;

[0010] The encoder is installed on the servo motor of the pile hoisting winch of the gravel pile construction ship. The encoder is used to measure and control the bottom elevation of the pile pipe in real time during the sinking process and the lifting process of the pile pipe;

[0011] The main controller is arranged in the cab of the gravel pile construction ship, and the main controller is respectively connected to the encoder, the weighing sensor and the radar rangefinder by signals;

[0012] The real-time monitoring method includes the following steps:

[0013] Step 1: First, set the parameters of the gravel pile in the display screen of the main controller, including the inner diameter d1 of the pile pipe, the diameter d2 of the gravel pile, the top elevation h1 of the gravel pile and the bottom elevation h2 of the gravel pile;

[0014] The main controller calculates the pile length H of the gravel pile according to formula (1):

[0015] H = h1 - h2 (1)

[0016] In formula (1), h1 is the top elevation of the gravel pile, and h2 is the bottom elevation of the gravel pile;

[0017] The main controller calculates the weight V0 of the theoretical gravel used for the gravel pile according to formula (2);

[0018] V0 = π × d2 2 / 4 × H (2)

[0019] In formula (2), d2 is the diameter of the gravel pile, that is, the inner diameter of the pile tip expansion section of the pile pipe;

[0020] The main controller calculates the weight V3 of the gravel loaded in the metering hopper according to formula (3):

[0021] V3 = M / ρ (3)

[0022] In formula (3), M is the mass of the gravel loaded in the metering hopper, and ρ is the loose density of the gravel;

[0023] The main controller calculates the number of hoppers X of the metering hopper required for the gravel added into the pile pipe during the pile forming process according to formula (4):

[0024] X = V0 / V3 (4)

[0025] If X is a non-integer, manually control the weight of the gravel in the metering hopper;

[0026] The main controller calculates the volume V4 per meter of the inner cavity of the pile pipe according to formula (5):

[0027] V4 = π × d1 2 / 4 (5)

[0028] In formula (5), d1 is the inner diameter of the pile pipe;

[0029] The main controller calculates the height h3 formed by the gravel of each metering hopper in the pile pipe according to formula (6):

[0030] h3 = V4 / V3 (6)

[0031] Step 2: First, close the upper and lower guide doors of the pile pipe and sink it by using the self-weight of the pile pipe. When the bottom of the pile pipe approaches the mud surface, turn on the pressurizing equipment to pressurize the inside of the pile pipe to drain the water inside the pile pipe. Monitor the water surface height inside the pile pipe through a radar rangefinder until the water surface height inside the pile pipe is 1 - 2 m, then stop pressurizing and continue to sink the pipe under the pressure-maintaining state. When the pile pipe cannot sink, turn on the vibrating hammer to vibrate and sink the pile pipe. When the pile pipe penetrates into the soil layer by 1 - 2 m, open the upper guide door to decompress and release air, and transport the crushed stone materials through the mutual cooperation of the belt conveyor and the lifting bucket and the metering bucket. The crushed stone materials are transported to the feeding hopper at the top of the pile pipe in batches, and two metering buckets of crushed stone materials are added to the pile pipe from the feeding hopper.

[0032] Step 3: Close the upper guide door, pressurize the inside of the pile pipe again, and then continue to vibrate and set the pile pipe to the designed pile bottom elevation under the pressure-maintaining state. During the process of sinking the pile pipe, the elevation GL of the bottom of the pile pipe is monitored in real time by the encoder installed on the servo motor of the pile hoisting winch.

[0033] Step 4: After the pile pipe vibrates and sinks to the designed bottom elevation, perform end treatment, that is, lift the pile pipe while maintaining a certain pressure inside the pipe to keep the top elevation of the crushed stone column inside the pile pipe unchanged, discharge the mud column that enters from the bottom of the pile pipe during the process of vibrating and setting the pile pipe outside the pile pipe, and then vibrate and sink the pile pipe to the designed bottom elevation again while keeping the pressure inside the pile pipe unchanged.

[0034] Step 5: Turn on the pile hoisting winch to lift the pile pipe so that the crushed stone materials inside the pile pipe are discharged from the bottom of the pile pipe. During the process of lifting the pile pipe, monitor the height SL of the crushed stone material level inside the pile pipe through the radar rangefinder installed in the feeding hopper at the top of the pile pipe, and automatically track the height of the remaining crushed stone materials inside the pile pipe. When the height of the crushed stone materials inside the pile pipe is less than 3 - 5 m, immediately stop lifting the pile pipe and add the remaining crushed stone materials to the pile pipe, and then lift the pile pipe again. During the process of lifting the pile pipe, monitor the change of the elevation GL of the bottom of the pile pipe through the encoder installed on the servo motor of the pile hoisting winch. The main controller calculates the weight V1 of the crushed stone materials discharged from the pile pipe when the pile pipe is lifted by a certain height according to the change of the height SL of the crushed stone material level inside the pile pipe and formula (7):

[0035] V1 = π×d1 2 (SL1 - SL2) / 4 (7)

[0036] In formula (7), d1 is the inner diameter of the pile pipe, SL1 is the height of the crushed stone material level inside the pile pipe before lifting the pile pipe, and SL2 is the height of the crushed stone material level inside the pile pipe after lifting the pile pipe by a certain height.

[0037] The main controller calculates the theoretical weight V2 of the crushed stone materials after lifting the pile pipe by a certain height according to the change of the elevation GL of the bottom of the pile pipe and formula (8):

[0038] V2 = π × d2 2 (GL2 - GL1) / 4 (8)

[0039] In formula (8), d2 is the pile diameter of the gravel pile, GL2 is the pile bottom elevation after lifting the pile pipe by a certain height, and GL1 is the pile bottom elevation before lifting the pile pipe;

[0040] The main controller also calculates the lifting rate SL' of the pile pipe according to formula (9):

[0041] SL' = V2 / V1 (9)

[0042] When SL' > 1, the lifting rate of the pile pipe needs to be slowed down. When SL' < 1, the lifting rate of the pile pipe needs to be increased;

[0043] Step six, the main controller compares the pile bottom elevation GL with the pile top elevation h1 input in step one, calculates the difference Δh = h1 - GL, calculates the difference Δh1 = SL - GL according to the height SL of the gravel material level in the pile pipe measured by the radar rangefinder, and then calculates the gravel quantity in the pile pipe = (π × d1 2 / 4 × Δh1) and calculates the required gravel quantity for pile formation according to the difference Δh = (π × d2 2 / 4 × Δh), then calculates the ratio of the gravel quantity in the pile pipe to the gravel quantity used for pile formation = (π × d1 2 / 4 × Δh1) / (π × d2 2 / 4 × Δh). If the ratio is greater than 1, the pile pipe needs to be pulled out above the pile top elevation h1 and then the pile pipe is driven down again to make the pile bottom elevation GL equal to the designed pile top elevation h1, and finally make the top elevation of the gravel pile consistent with the designed top elevation.

[0044] The real-time monitoring method for offshore gravel pile construction of the present invention has the following characteristics:

[0045] Based on the PLC monitoring system combined with the shipborne GPS system to monitor various states of offshore gravel pile construction. For the element data such as the material level in the pipe that is difficult to collect by traditional methods, a radar rangefinder is used for measurement. Through the feedback of the gravel material level, the pile formation quality of the gravel pile and the subsequent additional gravel quantity are judged. Through the lowering and lifting of the pile pipe during the construction process, data such as the pile bottom elevation, the height of the gravel surface in the pile pipe, and the length of the formed gravel pile can be intuitively reflected, enabling the operator to understand the situation of the formed gravel pile in real time, correctly guiding the construction of the gravel pile, and effectively controlling the pile formation quality of the gravel pile. Brief Description of the Drawings

[0046] Figure 1 is the flow chart of the real-time monitoring method for offshore gravel pile construction of the present invention;

[0047] Figure 2 It is a schematic diagram of the layout positions of each sensor in the PLC monitoring system adopted in the real-time monitoring method for offshore gravel pile construction of the present invention;

[0048] Figure 3 It is a schematic diagram of the principle for calculating the theoretical sand discharge amount and the measured sand discharge amount in step five of the real-time monitoring method for offshore gravel pile construction of the present invention. Specific embodiments

[0049] The present invention will be further described below in conjunction with the accompanying drawings.

[0050] Please refer to Figures 1 to 3 , the real-time monitoring method for offshore gravel pile construction of the present invention is based on a PLC monitoring system, and the PLC monitoring system includes a GPS positioning system, a radar rangefinder, a weighing sensor, an encoder, and a main controller; wherein,

[0051] The GPS positioning system 200 is arranged on the top of the cab 100 of the gravel pile construction ship. The GPS positioning system 200 is used to determine the position, direction, and attitude of the gravel pile construction ship in the engineering coordinate system, so as to determine the position of the gravel pile;

[0052] The radar rangefinder is arranged in the feed hopper 301 on the top of the pile pipe 300. The radar rangefinder is used to measure the height of the material level surface in the pile pipe 300 in real time;

[0053] The weighing sensor is arranged below the metering hopper 101 of the gravel pile construction ship; the weighing sensor is used to measure the weight of the gravel material added into the pile pipe 300 each time;

[0054] The encoder is installed on the servo motor of the pile hoisting winch 102 of the gravel pile construction ship. The encoder is used to measure and control the pile bottom elevation of the pile pipe 300 during the sinking process and the pile pipe 300 during the lifting process in real time;

[0055] The main controller is arranged in the cab 100 of the gravel pile construction ship, and the main controller is respectively connected to the encoder, the weighing sensor, and the radar rangefinder in signal.

[0056] The real-time monitoring method for offshore gravel pile construction of the present invention, the real-time monitoring method includes the following steps:

[0057] Step 1, first set the parameters of the gravel pile in the display screen of the main controller, including the inner diameter d1 of the pile pipe, the diameter d2 of the gravel pile, the top elevation h1 of the gravel pile, and the bottom elevation h2 of the gravel pile;

[0058] The main controller calculates the pile length H of the gravel pile according to formula (1):

[0059] H = h1 - h2 (1)

[0060] In formula (1), h1 is the top elevation of the gravel pile, and h2 is the bottom elevation of the gravel pile;

[0061] The main controller calculates the weight V0 of the theoretical gravel used for the gravel pile according to formula (2);

[0062] V0 = π×d2 2 / 4×H (2)

[0063] In formula (2), d2 is the diameter of the gravel pile, which is also the inner diameter of the tip expansion section of the pile pipe;

[0064] The main controller calculates the weight V3 of the gravel loaded in the metering hopper according to formula (3):

[0065] V3 = M / ρ (3)

[0066] In formula (3), M is the mass of the gravel loaded in the metering hopper, and ρ is the loose density of the gravel;

[0067] The main controller calculates the number of hoppers X of the metering hopper required for the gravel added to the pile pipe during the pile forming process according to formula (4):

[0068] X = V0 / V3 (4)

[0069] If X is a non-integer, manually control the weight of the gravel in the metering hopper;

[0070] The main controller calculates the volume V4 per meter of the inner cavity of the pile pipe according to formula (5):

[0071] V4 = π×d1 2 / 4 (5)

[0072] In formula (5), d1 is the inner diameter of the pile pipe;

[0073] The main controller calculates the height h3 formed by each metering hopper of gravel in the pile pipe according to formula (6):

[0074] h3 = V4 / V3 (6)

[0075] Step 2: First, close the upper guide door 302 and the lower guide door 303 of the pile pipe 300, and sink the pile pipe by using the self-weight of the pile pipe 300. When the bottom of the pile pipe 300 approaches the mud surface, start the pressurizing equipment to pressurize the inside of the pile pipe 300 to drain the water in the pile pipe 300. Monitor the water surface height inside the pile pipe 300 through a radar rangefinder until the water surface height inside the pile pipe 300 is 1 - 2 m, then stop pressurizing and continue to sink the pipe under the pressure-maintaining state. When the pile pipe cannot sink, start the vibratory hammer 304 to vibrate and sink the pile pipe 300. When the pile pipe 300 penetrates into the soil layer by a depth of 1 - 2 m, open the upper guide door 302 to relieve pressure and release gas, and convey the crushed stone materials through the mutual cooperation of the belt conveyor, the lifting bucket and the metering hopper 101. The crushed stone materials are conveyed to the feed hopper 301 at the top of the pile pipe 300 in batches, and two metering hoppers of crushed stone materials are added into the pile pipe 300 from the feed hopper 301, about 6 - 10 m 3 ;

[0076] Step 3: Close the upper guide door, and pressurize the inside of the pile pipe again to assist in the compaction and effective feeding of the crushed stone materials inside the pile pipe. Then continue to vibrate and drive the pile pipe to the designed pile bottom elevation under the pressure-maintaining state. During the process of sinking the pile pipe, the pile bottom elevation GL is monitored in real time by the encoder installed on the servo motor of the pile hoisting winch

[0077] Step 4: After the pile pipe is vibrated and sunk to the designed bottom elevation, carry out end treatment, that is, lift the pile pipe while maintaining a certain pressure inside the pipe to keep the top elevation of the crushed stone column inside the pile pipe unchanged, and discharge the mud column that enters from the bottom of the pile pipe during the process of vibrating and driving the pile pipe outside the pile pipe. Then, while keeping the pressure inside the pile pipe unchanged, vibrate and sink the pile pipe to the designed bottom elevation again

[0078] Step 5: Start the pile hoisting winch and lift the pile pipe at a constant speed of 1.0 - 2.0 m / min to discharge the crushed stone materials inside the pile pipe from the bottom of the pile pipe, so that the crushed stone materials remain in the soil layer. During the process of lifting the pile pipe, monitor the height SL of the crushed stone material level inside the pile pipe through the radar rangefinder installed in the feed hopper at the top of the pile pipe, automatically track the height of the remaining crushed stone materials inside the pile pipe, and ensure that the height of the crushed stone materials inside the pile pipe is not less than 3 - 5 m to prevent the soft soil outside the pile pipe from backfilling under the action of water pressure and soil pressure during the process of exhausting gas and adding crushed stone, resulting in the crushed stone pile being sandwiched with mud. When the height of the crushed stone materials inside the pile pipe is less than 3 - 5 m, immediately stop lifting the pile pipe and add the remaining crushed stone materials into the pile pipe, and then lift the pile pipe again. During the process of lifting the pile pipe, monitor the change of the pile bottom elevation GL through the encoder installed on the servo motor of the pile hoisting winch. The main controller calculates the weight V1 of the crushed stone materials discharged from the pile pipe when the pile pipe is lifted by a certain height according to the change of the high level SL of the crushed stone material level inside the pile pipe and formula (7):

[0079] V1 = π × d1 2 (SL1 - SL2) / 4 (7)

[0080] In formula (7), d1 is the inner diameter of the pile pipe, SL1 is the height of the crushed stone material level in the pile pipe before lifting the pile pipe, and SL2 is the height of the crushed stone material level in the pile pipe after lifting the pile pipe by a certain height (see Figure 2 );

[0081] The main controller calculates the theoretical weight V2 of the crushed stone material after lifting the pile pipe by a certain height according to the change of the pile pipe bottom elevation GL and formula (8):

[0082] V2 = π×d2 2 (GL2 - GL1) / 4 (8)

[0083] In formula (8), d2 is the pile diameter of the crushed stone pile, GL2 is the pile bottom elevation after lifting the pile pipe by a certain height, and GL1 is the pile bottom elevation before lifting the pile pipe;

[0084] The main controller also calculates the lifting rate SL' of the pile pipe according to formula (9):

[0085] SL' = V2 / V1 (9)

[0086] When SL' > 1, the lifting rate of the pile pipe needs to be slowed down. When SL' < 1, the lifting rate of the pile pipe needs to be accelerated;

[0087] Step six, the main controller compares the pile pipe bottom elevation GL with the pile top elevation h1 input in step one, calculates the difference △h = h1 - GL, calculates the difference △h1 = SL - GL according to the height SL of the crushed stone material level measured by the radar rangefinder, then calculates the amount of crushed stone in the pile pipe = (π×d1 2 / 4×△h1) and calculates the amount of crushed stone required for pile formation = (π×d2 2 / 4×△h), then calculates the ratio of the amount of crushed stone in the pile pipe to the amount of crushed stone used for pile formation = (π×d1 2 / 4×△h1) / (π×d2 2 / 4×△h). If the ratio is greater than 1, the pile pipe needs to be pulled out above the pile top elevation h1 and then the pile pipe is driven down again to make the pile pipe bottom elevation GL equal to the designed pile top elevation h1, and finally make the top elevation of the crushed stone pile consistent with the designed top elevation.

[0088] The above embodiments are only for illustrating the present invention, rather than limiting the present invention. Those skilled in the relevant technical fields can also make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by each claim.

Claims

1. A real-time monitoring method for offshore gravel pile construction, based on a PLC monitoring system. The PLC monitoring system includes a GPS positioning system, a radar rangefinder, a weighing sensor, an encoder, and a main controller; The GPS positioning system is installed on the top of the cab of the gravel pile construction ship. The GPS positioning system is used to determine the position, direction, and attitude of the gravel pile construction ship in the engineering coordinate system, so as to determine the position of the gravel pile; The radar rangefinder is installed in the feed hopper at the top of the pile pipe. The radar rangefinder is used to measure the height of the material level in the pile pipe in real time; The weighing sensor is installed below the measuring hopper of the gravel pile construction ship; the weighing sensor is used to measure the weight of the gravel material added into the pile pipe each time; The encoder is installed on the servo motor of the pile hoisting winch of the gravel pile construction ship. The encoder is used to measure and control the bottom elevation of the pile pipe during the sinking process and the lifting process of the pile pipe in real time; The main controller is installed in the cab of the gravel pile construction ship. The main controller is respectively connected to the encoder, the weighing sensor, and the radar rangefinder by signals; It is characterized in that, The real-time monitoring method includes the following steps: Step 1, first set the parameters of the gravel pile in the display screen of the main controller, including the inner diameter d1 of the pile pipe, the diameter d2 of the gravel pile, the top elevation h1 of the gravel pile, and the bottom elevation h2 of the gravel pile; The main controller calculates the pile length H of the gravel pile according to formula (1): H = h1 - h2 (1) In formula (1), h1 is the top elevation of the gravel pile, and h2 is the bottom elevation of the gravel pile; The main controller calculates the theoretical weight V0 of the gravel material used for the gravel pile according to formula (2); V0 = π×d2 2 / 4×H (2) In formula (2), d2 is the pile diameter of the gravel pile, that is, the inner diameter of the pile tip expansion section of the pile pipe; The main controller calculates the weight V3 of the gravel material loaded in the measuring hopper according to formula (3): V3 = M / ρ (3) In formula (3), M is the mass of the gravel material loaded in the measuring hopper, and ρ is the loose density of the gravel material; The main controller calculates the number of hoppers X of the measuring hopper required for the gravel material added into the pile pipe during the pile forming process according to formula (4): X = V0 / V3 (4) If X is a non-integer, manually control the weight of the gravel material in the measuring hopper; The main controller calculates the volume V4 per meter of the inner cavity of the pile pipe according to formula (5): V4 = π × d1 2 / 4 (5) In formula (5), d1 is the inner diameter of the pile pipe; The main controller calculates the height h3 formed by each measuring hopper of the gravel material in the pile pipe according to formula (6): h3 = V4 / V3 (6) Step 2, first close the upper and lower guide doors of the pile pipe and sink it by using the self-weight of the pile pipe; when the bottom of the pile pipe is close to the mud surface, turn on the pressurizing equipment, pressurize the pile pipe to discharge the water in the pile pipe, and monitor the water surface height in the pile pipe through the radar rangefinder until the water surface height in the pile pipe is 1 - 2m, stop pressurizing, and continue to sink the pipe in the pressure holding state; when the pile pipe cannot sink, turn on the vibrating hammer to vibrate and sink the pile pipe. When the pile pipe enters the soil layer to a depth of 1 - 2m, open the upper guide door to relieve pressure and release gas, and transport the gravel material through the cooperation of the belt conveyor and the lifting hopper and the measuring hopper. The gravel material is transported to the feed hopper at the top of the pile pipe in batches, and two measuring hoppers of gravel material are added into the pile pipe from the feed hopper; Step 3: Close the upper guide door, pressurize the pile pipe again, and then continue to vibrate and set the pile pipe to the designed pile bottom elevation under the pressure-holding state; during the process of sinking the pile pipe, the elevation GL of the pile pipe bottom is monitored in real time by the encoder installed on the servo motor of the pile hoisting winch. Step 4: After the pile pipe is vibrated and sunk to the designed bottom elevation, perform end treatment, that is, lift the pile pipe while maintaining a certain pressure inside the pipe to keep the top elevation of the gravel column inside the pile pipe unchanged, discharge the mud column that entered from the bottom of the pile pipe during the process of vibrating and setting the pile pipe outside the pile pipe, and then vibrate and sink the pile pipe to the designed bottom elevation again while keeping the pressure inside the pile pipe unchanged. Step 5: Start the pile hoisting winch to lift the pile pipe so that the gravel inside the pile pipe is discharged from the bottom of the pile pipe; during the process of lifting the pile pipe, the height SL of the gravel surface inside the pile pipe is monitored by the radar rangefinder installed in the feed hopper at the top of the pile pipe, and the height of the remaining gravel inside the pile pipe is automatically tracked; when the height of the gravel inside the pile pipe is less than 3 - 5 m, immediately stop lifting the pile pipe and add the remaining gravel into the pile pipe, and then lift the pile pipe again; during the process of lifting the pile pipe, the change in the elevation GL of the pile pipe bottom is monitored by the encoder installed on the servo motor of the pile hoisting winch; the main controller calculates the weight V1 of the gravel discharged from the pile pipe when the pile pipe is lifted by a certain height according to the change in the height SL of the gravel surface inside the pile pipe and formula (7): V1 = π × d1 2 (SL1 - SL2) / 4 (7) In formula (7), d1 is the inner diameter of the pile pipe, SL1 is the height of the gravel surface inside the pile pipe before lifting the pile pipe, and SL2 is the height of the gravel surface inside the pile pipe after lifting the pile pipe by a certain height. The main controller calculates the theoretical weight V2 of the gravel after lifting the pile pipe by a certain height according to the change in the elevation GL of the pile pipe bottom and formula (8): V2 = π×d2 2 (GL2 - GL1) / 4 (8) In formula (8), d2 is the pile diameter of the gravel pile, that is, the inner diameter of the pile tip expansion section of the pile pipe; GL2 is the pile bottom elevation after lifting the pile pipe by a certain height, and GL1 is the pile bottom elevation before lifting the pile pipe. The main controller also calculates the lifting rate SL' of the pile pipe according to formula (9): SL' = V2 / V1 (9) When SL' > 1, the lifting rate of the pile pipe should be slowed down; when SL' < 1, the lifting rate of the pile pipe should be accelerated. Step 6: The main controller compares the bottom elevation GL of the pile pipe with the top elevation h1 input in Step 1, calculates the difference Δh = h1 - GL, calculates the difference Δh1 = SL - GL based on the height SL of the crushed stone material level in the pile pipe measured by the radar rangefinder, and then calculates the amount of crushed stone in the pile pipe = (π × d1 2 / 4 × Δh1) and calculates the amount of crushed stone required for pile formation = (π × d2 2 / 4 × Δh), then calculates the ratio of the amount of crushed stone in the pile pipe to the amount of crushed stone used for pile formation = (π × d1 2 / 4 × Δh1) / (π × d2 2 / 4 × Δh). If the ratio is greater than 1, the pile pipe needs to be pulled out above the top elevation h1 of the pile and then the pile pipe is driven down again to make the bottom elevation of the pile pipe equal to the designed top elevation of the pile, so that the top elevation of the final crushed stone pile is consistent with the designed top elevation.

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