A construction method and system for non-destructive breaking of a pile head of a cast-in-place pile in a complex stratum

Abstract

This invention relates to a method and system for non-destructive demolition of pile heads in complex strata, relating to the field of cast-in-place piles. The method includes: acquiring soil parameters; analyzing soil parameters to determine a flow coefficient; selecting a minimum reference grouting volume based on the flow coefficient and acquiring pile images; identifying the pile driving depth from the pile images; matching grouting points based on the pile driving depth and determining the grouting depth based on the grouting points; determining the grouting volume at each point by combining the grouting depth and the reference grouting volume, and matching a consolidation reference duration based on the grouting volume at each point; matching a depth coefficient based on the flow coefficient and the grouting depth, and matching a consolidation coefficient based on the depth coefficient; determining a consolidation adjustment duration by combining the consolidation reference duration and the consolidation coefficient; and updating the pre-grouting command in response to the grouting volume at each point and the consolidation adjustment duration. This application improves the safety of cast-in-place pile construction and reduces surface deformation after pile extraction.

Description

Technical Field

[0001] This invention relates to the field of cast-in-place piles, and in particular to a method and system for non-destructive demolition of the pile head of cast-in-place piles in complex strata. Background Technology

[0002] A cast-in-place pile is a type of pile formed by drilling a hole at the pile location on the construction site, inserting a steel cage, and then pouring concrete.

[0003] In existing technologies, SMW (Self-Mixed Mixing) piles are widely used as retaining structures in foundation pit engineering. Generally, a triaxial or biaxial mixing drilling rig is first used to forcibly mix cement slurry with the original foundation soil to form a continuous overlapping cement-soil mixture. Then, before the cement-soil initially sets, core materials such as H-beams are inserted into the mixing wall to form a composite retaining structure with high strength and good water-stopping performance. After the internal structure of the foundation pit is completed, a vibratory hammer or hydraulic extraction equipment is used to liquefy the soil around the pile, thereby temporarily reducing the frictional resistance between the soil and the steel section, and then the steel section is pulled out from the cement-soil wall for recovery. The gaps left after the steel section is pulled out need to be filled with grout to control surface settlement and deformation of the surrounding environment.

[0004] When the soil in the project site is soft soil such as silt, due to the characteristics of silty soil such as high water content, high void ratio, strong fluidity and low strength, the hole formed after the steel is pulled out will be quickly closed under the action of soil lateral pressure. This makes it difficult for the subsequent grouting pipe to be inserted to the predetermined depth. The grout cannot be effectively injected into the hole and form a uniform solidified body before the soil closes, which will cause large-scale displacement of the soil towards the hole, resulting in surface subsidence and cracking, and posing a safety hazard to nearby roads, pipelines and buildings. Summary of the Invention

[0005] To improve the safety of cast-in-place pile construction and reduce surface deformation after pile extraction, this invention provides a method and system for non-destructive removal of the pile head in complex strata.

[0006] In a first aspect, the present invention provides a method for non-destructive removal of pile heads in complex strata, employing the following technical solution: A method for non-destructive demolition of pile heads in complex strata includes: Step 100: Collect soil parameters; Step 101: Analyze the soil parameters to determine the flow coefficient; Step 102: Select the minimum reference grouting volume based on the flow coefficient and acquire pile images; Step 103: Identify the pile driving depth from the pile image; Step 104: Match the grouting points according to the pile driving depth, and determine the grouting depth based on the grouting points; Step 105: Determine the grouting volume at the point by combining the grouting depth and the reference grouting volume, and match the consolidation reference time according to the grouting volume at the point; Step 106: Match the depth coefficient with the flow coefficient and the grouting depth, and match the consolidation coefficient with the depth coefficient; Step 107: Determine the consolidation adjustment time by combining the consolidation reference time and the consolidation coefficient; Step 108: In response to the grouting volume and consolidation adjustment time at the said location, a pre-grouting command is generated and sent.

[0007] By adopting the above technical solution, soil parameters are collected and soil fluidity is quantified to determine the flow coefficient. Based on this, the minimum benchmark grouting volume is selected, and the grouting volume at each point is determined in conjunction with the pile driving depth. At the same time, the consolidation benchmark time is matched according to the grouting volume at each point. The flow coefficient and grouting depth are introduced to obtain the depth coefficient and consolidation coefficient, and the consolidation adjustment time is dynamically determined. In this way, grouting is performed in advance before pile extraction and the soil is allowed to consolidate with grout, reducing the surface deformation after pile extraction and improving the safety of cast-in-place pile construction.

[0008] Optional, also includes: Step 109: Identify the pile position from the pile image based on the consolidation adjustment time; Step 110: Determine the number of piles by counting their locations; Step 111: Match the number of interval piles according to the number of piles, and select the initial position from the pile positions according to the consolidation adjustment time; Step 112: Select candidate locations from the pile positions based on the number of interval piles and the initial position; Step 113: Determine the nearest position based on the candidate positions and consolidation adjustment time, and generate the pull-out sequence by combining the nearest position and the initial position; Step 114: In response to the generated and sent pile jumping command in the jumping sequence.

[0009] By adopting the above technical solution, the location and number of piles can be identified after the grout has solidified, the number of interval piles can be matched and the extraction sequence can be generated, so that the piles can be extracted in sequence according to the solidification progress. This improves the efficiency of pile extraction while reducing the disturbance to the soil during the extraction process, thereby improving the safety of cast-in-place pile construction.

[0010] Optionally, a secondary grouting method may also be included, wherein the secondary grouting method includes: Step 200: Determine the pile extraction sequence based on the pile body jump extraction command; Step 201: Determine the pile extraction depth according to the pile extraction sequence; Step 202: Determine the pile extraction speed according to the pile extraction depth; Step 203: Generate a pile extraction control curve based on the pile extraction speed, and determine the extraction volume based on the pile extraction control curve; Step 204: Determine the filling rate curve based on the extracted volume; Step 205: Update the pile jumping command by combining the pile extraction control curve and the filling rate curve.

[0011] By adopting the above technical solution, during the pile extraction process, the pile extraction speed is determined according to the pile extraction depth and a pile extraction control curve is generated. Then, the filling rate curve of the grout is derived from the extracted volume, so as to realize the linkage between the pile extraction speed and the grouting speed, improve the matching between the hole volume and the grouting volume, and thus improve the safety of the cast-in-place pile construction.

[0012] Optionally, the secondary grouting method further includes: Step 206: Determine the volume difference based on the extracted volume, and read the difference rate from the filling rate curve; Step 207: Determine the filling time by combining the volume difference value and the difference rate; Step 208: Match the lag duration according to the filling duration; Step 209: Generate a grouting pipe recovery curve by combining the lag time and the pile extraction control curve; Step 210: In response to the grouting pipe recovery curve update pile body pull-out command.

[0013] By adopting the above technical solution, the volume difference and difference rate are calculated from the extracted volume, the filling time is determined and the lag time is matched, thereby reducing the situation of insufficient filling due to premature recovery or burying of the grouting pipe due to late recovery, coordinating the time difference between pile extraction and grouting pipe recovery, and thus improving the safety of cast-in-place pile construction.

[0014] Optionally, the secondary grouting method further includes: Step 211: Determine the filling volume based on the filling rate curve; Step 212: Determine the filling depth by comparing the filling volume and the pile extraction depth; Step 213: Retrieve the pre-grouting volume based on the filling depth; Step 214: Combine the pre-grouting volume and depth coefficient to determine the consolidation time, and compare the filling depth and pile extraction control curve to determine the idle time; Step 215: Calculate the difference between the consolidation time and the idle time, and define it as the remaining time; Step 216: Determine the grouting coefficient based on the remaining time; Step 217: Update the filling rate curve in response to the grouting coefficient.

[0015] By adopting the above technical solution, the filling depth of the grout is determined by comparing the filling volume and the extraction volume, and the consolidation time for the soil to remain stable is calculated in combination with the pre-injected grout volume. Thus, the idle time of the soil after pile extraction that has not been filled with grout is calculated. Then, the remaining time for the soil to remain stable is obtained by comparing the consolidation time and the idle time, and the filling rate curve is updated. This allows for dynamic optimization of grouting parameters and reduces the situation of soil displacement caused by failure to inject grout in time.

[0016] Optionally, a nozzle protection method may also be included, the nozzle protection method comprising: Step 300: Determine the extrusion ratio by combining the remaining time and consolidation time; Step 301: Determine the extrusion pressure based on the extrusion ratio, pre-grouting volume, and depth coefficient; Step 302: Match the anti-clogging flow rate according to the extrusion pressure; Step 303: Update the filling rate curve in response to the anti-blocking flow rate.

[0017] By adopting the above technical solution, the compression ratio is calculated by combining the remaining time and consolidation time, thereby determining the compression pressure of the soil on the grouting pipe, and then matching a suitable anti-clogging flow velocity, thus converting the degree of soil compression into a velocity constraint, forcing the grouting speed to be no less than the anti-clogging flow velocity, and actively preventing nozzle blockage.

[0018] Optionally, the nozzle protection method further includes: Step 304: Extract the recovery rate based on the grouting pipe recovery curve, and determine the friction coefficient according to the pre-grouting amount; Step 305: Determine the recovery pressure based on the recovery rate and friction coefficient; Step 306: Update the extrusion pressure in response to the recovery pressure; Step 307: When the extrusion pressure is greater than the preset damage threshold, determine the upper limit of the rate by combining the friction coefficient and the preset damage threshold; Step 308: Update the grouting pipe recovery curve in response to the rate limit.

[0019] By adopting the above technical solution, the friction coefficient and recovery pressure are determined by extracting the recovery rate and the pre-grouting volume. When the extrusion pressure exceeds the threshold, the upper limit of the rate is calculated and the recovery curve is updated. This reduces the situation where the pressure on the nozzle is too high due to the excessive recovery speed of the grouting pipe, which could lead to nozzle damage and improve the safety of cast-in-place pile construction.

[0020] Optionally, the nozzle protection method further includes: Step 309: When the consolidation time is less than the preset recycling threshold, retrieve the protection depth based on the consolidation time; Step 310: Match the protection speed according to the protection depth; Step 311: Determine the protection interval according to the protection speed; Step 312: Generate a nozzle protection curve by combining the protection speed and protection interval; Step 313: In response to the nozzle protection curve update pile jump command.

[0021] By adopting the above technical solution, when the soil consolidation degree is too low and the grouting pipe does not have enough time for grouting, the protection depth, protection speed and protection interval are retrieved to generate a nozzle protection curve, thereby providing a graded speed and intermittent withdrawal strategy, reducing the situation where the grouting pipe is buried by the soil, and at the same time reducing the situation where the nozzle is damaged due to excessive grouting pipe recovery speed, thus improving the safety of cast-in-place pile construction.

[0022] Secondly, this application provides a non-destructive demolition system for pile heads in complex strata, employing the following technical solution: A non-destructive demolition system for pile heads in complex strata includes: The acquisition module is used to acquire soil parameters and pile images; The memory is used to store the program for the non-destructive demolition method of the pile head of any of the above-mentioned complex strata cast-in-place piles; The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0023] By adopting the above technical solution, soil parameters are collected and soil fluidity is quantified to determine the flow coefficient. Based on this, the minimum benchmark grouting volume is selected, and the grouting volume at each point is determined in conjunction with the pile driving depth. At the same time, the consolidation benchmark time is matched according to the grouting volume at each point. The flow coefficient and grouting depth are introduced to obtain the depth coefficient and consolidation coefficient, and the consolidation adjustment time is dynamically determined. In this way, grouting is performed in advance before pile extraction and the soil is allowed to consolidate with grout, reducing the surface deformation after pile extraction and improving the safety of cast-in-place pile construction.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. Collect soil parameters and quantify soil fluidity to determine the flow coefficient. Based on this, select the minimum benchmark grouting volume and determine the grouting volume at each point in conjunction with the pile driving depth. At the same time, match the consolidation benchmark time according to the grouting volume at each point. Introduce the flow coefficient and grouting depth to obtain the depth coefficient and consolidation coefficient. Dynamically determine the consolidation adjustment time, so as to pre-grout before pile extraction and wait for the grout to consolidate the soil, reduce the surface deformation after pile extraction, and improve the safety of cast-in-place pile construction. 2. After the grout has solidified, the location and number of piles are identified, the number of interval piles is matched, and a jump-extraction sequence is generated. Thus, the piles are extracted sequentially according to the consolidation progress, which improves the efficiency of pile extraction while reducing the disturbance to the soil during the extraction process, thereby improving the safety of cast-in-place pile construction. 3. During the pile extraction process, the extraction speed is determined based on the extraction depth, and a pile extraction control curve is generated. Then, the filling rate curve of the grout is derived from the extracted volume, so as to realize the linkage between the extraction speed and the grouting speed, improve the matching between the hole volume and the grouting volume, and thus improve the safety of the cast-in-place pile construction. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a non-destructive demolition method for pile heads in complex strata. Figure 2 This is a flowchart of a construction method for non-destructive removal of pile heads in complex strata. Figure 3 This is a flowchart of the secondary grouting method.

[0026] The locations indicated by the numbers in the attached diagrams are as follows: 1. Protected target; 2. Pile body; 3. Grouting pipe; 4. Nozzle; 5. Consolidated soil. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] Reference Figure 1 A method for non-destructive demolition of pile heads in complex strata, comprising: Step 100: Collect soil parameters.

[0029] Soil parameters refer to a set of data reflecting the physical and mechanical properties of the strata in the area to be constructed, including but not limited to moisture content, shear strength, pore water pressure, and depth confining pressure. The data collection methods can include on-site drilling and sampling combined with indoor geotechnical tests, or in-situ testing equipment (such as a static cone penetrometer) to directly obtain continuous profile parameters. In this embodiment, before the construction of the pile foundation, an exploration point is set up every 20m along the edge of the foundation pit. A thin-walled soil sampler is used to collect undisturbed soil samples and measure various parameters as soil parameters. The method of collecting soil parameters is selected by the staff according to the actual situation.

[0030] Step 101: Analyze the soil parameters to determine the flow coefficient.

[0031] The flow coefficient is a dimensionless index that characterizes the tendency of surface soil to become fluid. The higher the water content, the lower the shear strength, the greater the pore water pressure, and the smaller the depth confining pressure, the larger the flow coefficient. This indicates that the soil is more fluid and has a poorer self-stabilizing ability. The flow coefficient corresponding to the soil parameters can be found in the flow coefficient table. The flow coefficient table is a data table that records different soil parameters and their corresponding flow coefficients.

[0032] The process involves pre-collecting soil moisture content, shear strength, pore water pressure, and depth confining pressure, and then performing dimensionless normalization on multiple sets of parameters. The normalized moisture content, shear strength, pore water pressure, and depth confining pressure are then coupled to obtain the flow coefficient. Finally, the original moisture content, shear strength, pore water pressure, and depth confining pressure, along with the corresponding flow coefficient, are used as a set of data to fill into the flow coefficient table. A complete flow coefficient table is then formed using interpolation. The data tables mentioned below are constructed following the same steps.

[0033] Step 102: Select the minimum reference grouting volume based on the flow coefficient and acquire pile images.

[0034] The reference grouting volume refers to the minimum grouting volume required per unit pile length under the current flow coefficient conditions. The larger the flow coefficient, the larger the reference grouting volume. The reference grouting volume corresponding to the flow coefficient can be found in the reference grouting table, which is a data table that records different flow coefficients and their corresponding reference grouting volumes.

[0035] A pile image refers to a picture of a pile 2 driven into the soil and exposed outside the soil. The pile 2 is driven into one side of the protected target 1 to form a retaining structure. The pile image can be obtained by taking a picture of the pile arrangement from a high place using an industrial camera or a drone. The method of acquiring the pile image is selected by the staff according to the actual situation.

[0036] Step 103: Identify the pile driving depth from the pile image.

[0037] The pile driving depth refers to the distance from the ground surface to the bottom of each pile. Image recognition technology can be used to mark the coordinates of the top of each pile (the highest point of the pile body 2 exposed outside the soil), and then the pile length data in the construction record can be read. Finally, the difference between the pile length data and the pile top coordinates is calculated as the pile driving depth.

[0038] Step 104: Match the grouting points according to the pile driving depth, and determine the grouting depth based on the grouting points.

[0039] Grouting point refers to the location of nozzle 4 on grouting pipe 3. Nozzles 4 are evenly distributed on grouting pipe 3. When grouting pipe 3 is driven into the soil layer with pile body 2, nozzles 4 are evenly distributed in the vertical direction of the soil layer. The lowest grouting point is the pile bottom. Other grouting points are automatically calculated based on the position of the pile bottom and the spacing of nozzles 4. The calculation method for grouting points is selected by the staff according to the actual situation.

[0040] Grouting depth refers to the soil depth where nozzle 4 is located, that is, the distance between the grouting point and the ground surface. The method for determining the grouting depth is selected by the staff based on the actual situation.

[0041] Step 105: Determine the grouting volume at the point by combining the grouting depth and the reference grouting volume, and match the consolidation reference time according to the grouting volume at the point.

[0042] The grouting volume at a point refers to the volume of grout required to be injected at the grouting depth by the nozzle 4. The grout refers to the material used to fill the holes. Generally, cement-water glass double-liquid grout is used as the grout. The larger the grouting depth and the reference grouting volume, the larger the grouting volume at the point. The grouting volume at the point corresponding to the grouting depth and the reference grouting volume can be found in the grouting correspondence table. The grouting correspondence table is a data table that records different grouting depths and reference grouting volumes and their corresponding grouting volumes at points.

[0043] Consolidation reference time refers to the minimum time required for grout and soil to fully mix and solidify to form consolidated soil under standard conditions. The larger the grouting volume at a point, the longer the consolidation reference time. The consolidation reference time corresponding to the grouting volume at a point can be found in the consolidation reference time table. The consolidation reference time table is a data table that records different grouting volumes at points and their corresponding consolidation reference times.

[0044] Step 106: Match the depth coefficient with the flow coefficient and the grouting depth, and match the consolidation coefficient with the depth coefficient.

[0045] The depth coefficient refers to the flow coefficient of the same soil at different depths. The smaller the flow coefficient, the larger the grouting depth, and the smaller the depth coefficient. The flow coefficient and the depth coefficient corresponding to the grouting depth can be found in the depth correspondence table. The depth correspondence table is a data table that records different flow coefficients and grouting depths and their corresponding depth coefficients.

[0046] The consolidation coefficient is a numerical value that characterizes the degree of influence of the depth coefficient on the consolidation reference time. The larger the depth coefficient, the easier the soil is to flow, and the more difficult it is for the grout and soil layer to form a stable consolidated soil. The larger the consolidation coefficient, the more likely it is to be found in the consolidation correspondence table. The consolidation correspondence table is a data table that records different depth coefficients and their corresponding consolidation coefficients.

[0047] Step 107: Determine the consolidation adjustment time by combining the consolidation reference time and the consolidation coefficient.

[0048] Consolidation adjustment time refers to the minimum time required for the grout to fully mix and solidify with the soil to form consolidated soil. It can be calculated as the product of the consolidation reference time and the consolidation coefficient.

[0049] Step 108: In response to the grouting volume and consolidation adjustment time at the said location, a pre-grouting command is generated and sent.

[0050] The pre-grouting command is a control signal sent to the nozzle 4. The pre-grouting command controls the electric valve of the nozzle 4 at the corresponding grouting point to open according to the grouting volume at the point, and waits for the consolidation adjustment time after grouting to form a stable consolidated soil body 5. The method of generating the pre-grouting command is selected by the staff according to the actual situation.

[0051] Soil parameters are collected and soil fluidity is quantified to determine the flow coefficient. Based on this, the minimum benchmark grouting volume is selected, and the grouting volume at each point is determined in conjunction with the pile driving depth. At the same time, the consolidation benchmark time is matched according to the grouting volume at each point. The flow coefficient and grouting depth are introduced to obtain the depth coefficient and consolidation coefficient. The consolidation adjustment time is dynamically determined, so that grouting is performed in advance before pile extraction and the soil is allowed to consolidate with grout. This reduces the surface deformation after pile extraction and improves the safety of cast-in-place pile construction.

[0052] A method for non-destructive demolition of pile heads in complex strata also includes: Step 109: Identify the pile position from the pile image based on the consolidation adjustment time.

[0053] The location of a pile refers to the coordinates of each construction pile. The location of a pile can be identified through image recognition technology. The method for identifying the location of a pile is common knowledge to those in the field.

[0054] Step 110: Count the locations of the piles to determine the number of piles.

[0055] The number of piles refers to the total number of piles in the construction method. The number of pile locations can be counted as the number of piles. Whenever a pile of a certain construction method is extracted, the number of piles is updated in a timely manner.

[0056] Step 111: Match the number of interval piles according to the number of piles, and select the initial position from the pile positions according to the consolidation adjustment time.

[0057] The number of interval piles refers to the minimum number of intervals required to avoid affecting the soil containing other piles when extracting a pile. The larger the number of piles, the larger the number of interval piles. The number of interval piles corresponding to the number of piles can be found in the interval correspondence table. The interval correspondence table is a data table that records different numbers of piles and their corresponding number of interval piles.

[0058] The initial position refers to the position where the pile is first extracted, that is, the position where the grout first solidifies. The pile position corresponding to the shortest consolidation adjustment time can be selected as the initial position.

[0059] Step 112: Select candidate positions from the pile positions by combining the number of interval piles and the initial position.

[0060] Candidate locations refer to the locations of piles in which the soil is not affected after the initial pile 2 is pulled out. Pile locations that are a number of piles away from the initial location can be selected as candidate locations. The selection method for candidate locations is determined by the staff based on the actual situation.

[0061] Step 113: Determine the nearest position based on the candidate position and the consolidation adjustment time, and generate the pull-out sequence by combining the nearest position and the initial position.

[0062] The nearest position refers to the closest candidate position where the grout has solidified. The nearest position can be selected from the candidate positions that have been waiting for consolidation and adjustment time after grouting.

[0063] The pull-out sequence refers to the order in which the pile 2 at the initial position and the nearest position are pulled out in sequence. Steps 111 to 113 can be repeated by updating the nearest position to the initial position until the number of piles is 0. The obtained initial position and the nearest position are arranged in chronological order as the pull-out sequence.

[0064] Step 114: In response to the generated and sent pile jumping command in the jumping sequence.

[0065] The pile jumping and pulling command refers to the command to pull out pile 2 in sequence using static pile pulling equipment such as jacks. The method for generating the pile jumping and pulling command is selected by the staff according to the actual situation.

[0066] Once the grout has solidified, the location and number of piles are identified, the number of interval piles is matched, and a jump extraction sequence is generated. Thus, piles are extracted sequentially according to the solidification progress, which improves the efficiency of pile extraction while reducing the disturbance to the soil during the extraction process, thereby improving the safety of cast-in-place pile construction.

[0067] Reference Figure 2 Secondary grouting methods include: Step 200: Determine the pile extraction sequence based on the pile body jumping extraction command.

[0068] The pile extraction sequence refers to the sequence number of pile body 2 being extracted at this time. The order of the extracted pile body 2 in the jump extraction sequence can be used as the pile extraction sequence.

[0069] Step 201: Determine the pile extraction depth according to the pile extraction sequence.

[0070] The pile extraction depth refers to the driving depth of pile body 2 corresponding to the pile extraction sequence, which can be automatically retrieved by the system.

[0071] Step 202: Determine the pile extraction speed according to the pile extraction depth.

[0072] The pile extraction speed refers to the initial speed value of the pile extraction. The greater the pile extraction depth, the greater the pile extraction speed is used. The pile extraction speed corresponding to the pile extraction depth can be found in the pile extraction correspondence table, which is a data table that records different pile extraction depths and their corresponding pile extraction speeds.

[0073] Step 203: Generate a pile extraction control curve based on the pile extraction speed, and determine the extraction volume based on the pile extraction control curve.

[0074] The pile extraction control curve refers to the curve showing the pile extraction speed over time. It is generally achieved through segmented speed control, i.e., starting with a low speed, then a medium speed, and finally extracting the pile completely at a low speed. The initial low speed is the extraction speed. The corresponding mid-range and final speeds can be found in the pile extraction control table. The pile extraction speed, mid-range speed, and final speed are then combined to form a smooth curve over time, which serves as the pile extraction control curve. The pile extraction control table is a data table that records different pile extraction speeds and their corresponding mid-range and final speeds.

[0075] The extraction volume refers to the total volume of pile 2 pulled out from the hole. It can be calculated by integrating the pile extraction control curve and multiplying it by the cross-sectional area of ​​the steel section.

[0076] Step 204: Determine the filling rate curve based on the extracted volume.

[0077] The filling rate curve refers to the curve of the grout velocity output from the grouting pipe 3 changing with time. The larger the extraction volume, the greater the filling rate. The filling rate corresponding to different extraction volumes can be found in the filling rate table. Finally, the smooth curve formed by the filling rate and time is used as the filling rate curve.

[0078] While the pile body 2 is being pulled out, grout is injected into the hole formed by the pulled-out pile body 2 through the grouting pipe 3, thereby performing secondary grouting.

[0079] Step 205: Update the pile jumping command by combining the pile extraction control curve and the filling rate curve.

[0080] During the pile extraction process, the extraction speed is determined based on the extraction depth and a pile extraction control curve is generated. Then, the grout filling rate curve is derived from the extracted volume, realizing the linkage between the extraction and grouting speeds, improving the matching between the borehole volume and the grouting volume, and thus improving the safety of cast-in-place pile construction.

[0081] Secondary grouting methods also include: Step 206: Determine the volume difference based on the extracted volume, and read the difference rate from the filling rate curve.

[0082] The volume difference refers to the difference in the volume extracted at adjacent time points. The calculation method for the volume difference is selected by the staff based on the actual situation.

[0083] The difference rate refers to the filling rate corresponding to the volume difference. The filling rate at the corresponding time point can be read from the filling rate curve as the difference rate.

[0084] Step 207: Determine the filling time by combining the volume difference and the difference rate.

[0085] Filling time refers to the minimum time required to fill the hole of volume difference according to the difference rate, that is, the quotient of volume difference and difference rate is used as filling time.

[0086] Step 208: Match the lag duration according to the filling duration.

[0087] The lag time refers to the time required for the grouting pipe 3 to move after the pile body 2 has moved. The longer the filling time, the longer the lag time. The filling time can be directly used as the lag time, or the lag time corresponding to the filling time can be found from the lag time correspondence table. The lag time correspondence table is a data table that records different filling times and their corresponding lag times.

[0088] Step 209: Generate the grouting pipe recovery curve by combining the lag time and the pile extraction control curve.

[0089] The grouting pipe recovery curve refers to the curve of the rising speed of the grouting pipe 3 changing with time. The grouting pipe 3 initially rises synchronously with the pile body 2, and when the extraction speed of the pile body 2 fluctuates, it does not rise synchronously with the speed of the pile body 2 according to the grouting situation. The curve formed by delaying the lag time of each speed fluctuation point in the pile extraction control curve can be used as the grouting pipe recovery curve.

[0090] Step 210: In response to the grouting pipe recovery curve update pile body pull-out command.

[0091] The volume difference and rate of difference are calculated from the extracted volume to determine the filling time and match the lag time, thereby reducing the situation of insufficient filling due to premature recovery or burying of grouting pipe 3 due to late recovery. The time difference between pile extraction and grouting pipe 3 recovery is coordinated, thereby improving the safety of cast-in-place pile construction.

[0092] Secondary grouting methods also include: Step 211: Determine the filling volume based on the filling rate curve.

[0093] The filling volume refers to the total volume of grout that has been output from grouting pipe 3. The filling volume can be calculated by integrating the filling rate curve.

[0094] Step 212: Determine the filling depth by comparing the filling volume and the pile extraction depth.

[0095] The filling depth refers to the distance between the grout surface in the hole and the ground surface. It can be calculated by dividing the filling volume by the cross-sectional area of ​​the steel section, and then the difference between the pile extraction depth and the filling height is used as the filling depth.

[0096] Step 213: Retrieve the pre-injection volume based on the filling depth.

[0097] Pre-grouting volume refers to the grouting volume at the point corresponding to the filling depth. The nearest grouting points on both sides of the vertical direction of the filling depth and their corresponding grouting volumes can be retrieved. The distance between the filling depth and the grouting point is then calculated as the grouting distance. The grouting volume at the point is then calculated by weighting the grouting distance as the pre-grouting volume. The calculation method for the pre-grouting volume is selected by the staff according to the actual situation.

[0098] Step 214: Combine the pre-grouting volume and depth coefficient to determine the consolidation time, and compare the filling depth and pile extraction control curve to determine the idle time.

[0099] Consolidation time refers to the maximum duration for which consolidated soil 5 can remain stable. The larger the pre-grouting volume and the smaller the depth coefficient, the longer the consolidation time. The consolidation time corresponding to the pre-grouting volume and depth coefficient can be found in the consolidation time table. The consolidation time table is a data table that records different pre-grouting volumes and depth coefficients and their corresponding consolidation times.

[0100] The vacancy period refers to the time during which the soil layer in the hole is not filled with grout after the pile body 2 is pulled out. The corresponding pull-out time can be found from the pile pull-out control curve according to the filling depth, and then the time from the pull-out time to this moment can be calculated as the vacancy period.

[0101] Step 215: Calculate the difference between the consolidation time and the idle time, and define it as the remaining time.

[0102] The remaining duration refers to the maximum duration for which the consolidated soil 5 can remain stable.

[0103] Step 216: Determine the grouting coefficient based on the remaining time.

[0104] The grouting coefficient is a coefficient that corrects the filling speed according to the remaining time. The smaller the remaining time, the larger the grouting coefficient. The grouting coefficient corresponding to the remaining time can be found in the grouting coefficient table. Then, the product of the grouting coefficient and the original filling rate is calculated as the new filling rate and the filling rate curve is updated. The grouting coefficient table is a data table that records different remaining times and their corresponding grouting coefficients.

[0105] Step 217: Update the filling rate curve in response to the grouting coefficient.

[0106] The filling depth of the grout is determined by comparing the filling volume and the extraction volume. The consolidation time for the soil to remain stable is calculated by combining the pre-injected grout volume. The idle time of the soil after pile extraction that is not filled with grout is then calculated. The remaining time for the soil to remain stable is obtained by comparing the consolidation time and the idle time, and the filling rate curve is updated. This allows for dynamic optimization of grouting parameters and reduces the occurrence of soil displacement caused by failure to inject grout in a timely manner.

[0107] Sprayer head protection methods include: Step 300: Determine the extrusion ratio by combining the remaining time and the consolidation time.

[0108] The compression ratio is a value used to show the compression of the soil on the grouting pipe 3. It can be calculated as the quotient of the remaining time and the consolidation time. The smaller the compression ratio, the more the soil tends to flow.

[0109] Step 301: Determine the extrusion pressure based on the extrusion ratio, pre-grouting volume, and depth coefficient.

[0110] The squeezing pressure refers to the squeezing value of the soil on the grouting pipe 3. The smaller the squeezing ratio, the smaller the pre-grouting volume, and the larger the depth coefficient, the greater the squeezing pressure. The squeezing pressure corresponding to the squeezing ratio, pre-grouting volume, and depth coefficient can be found in the squeezing pressure table. The squeezing pressure table is a data table that records different squeezing ratios, pre-grouting volumes, and depth coefficients and their corresponding squeezing pressures.

[0111] Step 302: Match the anti-clogging flow rate according to the extrusion pressure.

[0112] The anti-clogging flow rate refers to the minimum slurry flow rate required for the nozzle 4 to avoid being blocked by the soil. The higher the extrusion pressure, the higher the anti-clogging flow rate. The anti-clogging flow rate corresponding to the extrusion pressure can be found in the anti-clogging correspondence table. When the filling rate is lower than the anti-clogging flow rate, the anti-clogging flow rate is used as the new filling rate. The anti-clogging correspondence table is a data table that records different extrusion pressures and their corresponding anti-clogging flow rates.

[0113] Step 303: Update the filling rate curve in response to the anti-blocking flow rate.

[0114] The compression ratio is calculated by combining the remaining time and consolidation time, thereby determining the compression pressure of the soil on the grouting pipe 3, and then matching a suitable anti-clogging flow velocity, thus converting the degree of soil compression into a velocity constraint, forcing the grouting speed to be no less than the anti-clogging flow velocity, and actively preventing the nozzle 4 from clogging.

[0115] Other methods for protecting nozzles include: Step 304: Extract the recovery rate based on the grouting pipe recovery curve, and determine the friction coefficient according to the pre-grouting amount.

[0116] The recovery rate refers to the real-time speed at which the grouting pipe 3 rises, and the value at this time can be read from the grouting pipe recovery curve as the recovery rate.

[0117] The friction coefficient refers to the value that shows the friction between the consolidated soil 5 and the nozzle 4. The larger the pre-grouting volume, the fewer the pores in the consolidated soil layer, and the smaller the friction coefficient. The friction coefficient corresponding to the pre-grouting volume can be found in the friction correspondence table, which is a data table that records different pre-grouting volumes and their corresponding friction coefficients.

[0118] Step 305: Determine the recovery pressure by combining the recovery rate and the friction coefficient.

[0119] Recovery pressure refers to the pressure increase caused by friction between the nozzle 4 and the sidewall of the hole as the nozzle 4 rises with the grouting pipe 3. The greater the recovery rate and the friction coefficient, the greater the recovery pressure. The recovery pressure corresponding to the recovery rate and the friction coefficient can be found in the recovery pressure table. The recovery pressure table is a data table that records different recovery rates and friction coefficients and their corresponding recovery pressures.

[0120] Step 306: Update the extrusion pressure in response to the recovery pressure.

[0121] The sum of the recovery pressure and the original extrusion pressure is calculated as the new extrusion pressure.

[0122] Step 307: When the extrusion pressure is greater than the preset damage threshold, determine the upper limit of the rate by combining the friction coefficient and the preset damage threshold.

[0123] The damage threshold refers to the maximum extrusion pressure that the nozzle 4 can withstand while remaining intact. The damage threshold is preset by the staff according to the model of the nozzle 4. If the extrusion pressure exceeds the damage threshold, it means that the nozzle 4 is subjected to excessive pressure during the ascent of the grouting pipe 3, which can easily lead to damage to the nozzle 4. The upper limit of the rate refers to the maximum speed at which the nozzle 4 can rise without damage. The upper limit of the rate corresponding to the friction coefficient and the damage threshold can be found in the recovery pressure table, and the grouting pipe recovery curve can be replaced with the upper limit of the rate to form a new grouting pipe recovery curve.

[0124] Step 308: Update the grouting pipe recovery curve in response to the rate limit.

[0125] The friction coefficient and recovery pressure are determined by the extraction and recovery rate and the pre-grouting volume. When the extrusion pressure exceeds the threshold, the upper limit of the rate is calculated and the recovery curve is updated. This reduces the situation where the pressure on the nozzle 4 is too high due to the excessive recovery speed of the grouting pipe 3, which could lead to damage to the nozzle 4 and improve the safety of the cast-in-place pile construction.

[0126] Other methods for protecting nozzles include: Step 309: When the consolidation time is less than the preset recycling threshold, retrieve the protection depth based on the consolidation time.

[0127] The recovery threshold refers to the minimum consolidation time required for nozzle 4 to fully output grout before soil compression. The recovery threshold is selected by the staff based on the actual situation. A consolidation time less than the recovery threshold indicates that the soil is compressing nozzle 4 too quickly, making it difficult for nozzle 4 to output sufficient grout within a limited time. The protection depth refers to the maximum protection depth when the consolidation time is too short, i.e., the filling depth corresponding to the first consolidation time less than the recovery threshold.

[0128] Step 310: Match the protection speed according to the protection depth.

[0129] The protection speed refers to the speed value used to promptly recover the grouting pipe 3 from the protection depth. The greater the protection depth, the greater the protection speed. The protection speed corresponding to the protection depth can be found in the protection speed table, which is a data table that records different protection depths and their corresponding protection speeds.

[0130] Step 311: Determine the protection interval according to the protection speed.

[0131] The protection interval refers to the intermittent time used to reduce excessive pressure accumulation caused by the continuous rise of the nozzle 4 along the grouting pipe 3. The higher the protection speed, the larger the protection interval is. The protection interval corresponding to the protection speed can be found in the protection interval table, which is a data table that records different protection speeds and their corresponding protection intervals.

[0132] Step 312: Generate a nozzle protection curve by combining the protection speed and protection interval.

[0133] The nozzle protection curve refers to the curve of the rising speed of the grouting pipe 3 changing with time. That is, after each protection interval according to the protection speed, the rising will stop for a preset stop time. The stop time can be 1 second, and the stop time is selected by the staff according to the actual situation.

[0134] Step 313: In response to the nozzle protection curve update pile jump command.

[0135] When the soil consolidation is too low, resulting in insufficient time for grouting through the grouting pipe 3, the protection depth, protection speed, and protection interval are retrieved to generate a protection curve for the nozzle 4. This provides a graded speed and intermittent withdrawal strategy, reducing the possibility of the grouting pipe 3 being buried by the soil. It also reduces the possibility of the nozzle 4 being damaged due to excessive grouting pipe 3 recovery speed, thereby improving the safety of cast-in-place pile construction.

[0136] Based on the same inventive concept, embodiments of the present invention provide a non-destructive demolition system for pile heads in complex strata, comprising: The acquisition module is used to acquire soil parameters and pile images; The memory is used to store the program for the non-destructive demolition method of the pile head of any of the above-mentioned complex strata cast-in-place piles; The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0137] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0138] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for non-destructive demolition of pile heads in complex strata, characterized in that, include: Step 100: Collect soil parameters; Step 101: Analyze the soil parameters to determine the flow coefficient; Step 102: Select the minimum reference grouting volume based on the flow coefficient and acquire pile images; Step 103: Identify the pile driving depth from the pile image; Step 104: Match the grouting points according to the pile driving depth, and determine the grouting depth based on the grouting points; Step 105: Determine the grouting volume at the point by combining the grouting depth and the reference grouting volume, and match the consolidation reference time according to the grouting volume at the point; Step 106: Match the depth coefficient with the flow coefficient and the grouting depth, and match the consolidation coefficient with the depth coefficient; Step 107: Determine the consolidation adjustment time by combining the consolidation reference time and the consolidation coefficient; Step 108: In response to the grouting volume and consolidation adjustment time at the said location, a pre-grouting command is generated and sent.

2. The method for non-destructive demolition of pile heads in complex strata according to claim 1, characterized in that, Also includes: Step 109: Identify the pile position from the pile image based on the consolidation adjustment time; Step 110: Determine the number of piles by counting their locations; Step 111: Match the number of interval piles according to the number of piles, and select the initial position from the pile positions according to the consolidation adjustment time; Step 112: Select candidate locations from the pile positions based on the number of interval piles and the initial position; Step 113: Determine the nearest position based on the candidate positions and consolidation adjustment time, and generate the pull-out sequence by combining the nearest position and the initial position; Step 114: In response to the generated and sent pile pulling command in the order of the pull-out sequence.

3. The method for non-destructive demolition of pile heads in complex strata according to claim 2, characterized in that, It also includes a secondary grouting method, which includes: Step 200: Determine the pile extraction sequence based on the pile body jump extraction command; Step 201: Determine the pile extraction depth according to the pile extraction sequence; Step 202: Determine the pile extraction speed according to the pile extraction depth; Step 203: Generate a pile extraction control curve based on the pile extraction speed, and determine the extraction volume based on the pile extraction control curve; Step 204: Determine the filling rate curve based on the extracted volume; Step 205: Update the pile jumping command by combining the pile extraction control curve and the filling rate curve.

4. The method for non-destructive demolition of pile heads in complex strata according to claim 3, characterized in that, The secondary grouting method further includes: Step 206: Determine the volume difference based on the extracted volume, and read the difference rate from the filling rate curve; Step 207: Determine the filling time by combining the volume difference value and the difference rate; Step 208: Match the lag duration according to the filling duration; Step 209: Generate a grouting pipe recovery curve by combining the lag time and the pile extraction control curve; Step 210: In response to the grouting pipe recovery curve update pile body pull-out command.

5. The method for non-destructive demolition of pile heads in complex strata according to claim 4, characterized in that, The secondary grouting method further includes: Step 211: Determine the filling volume based on the filling rate curve; Step 212: Determine the filling depth by comparing the filling volume and the pile extraction depth; Step 213: Retrieve the pre-grouting volume based on the filling depth; Step 214: Combine the pre-grouting volume and depth coefficient to determine the consolidation time, and compare the filling depth and pile extraction control curve to determine the idle time; Step 215: Calculate the difference between the consolidation time and the idle time, and define it as the remaining time; Step 216: Determine the grouting coefficient based on the remaining time; Step 217: Update the filling rate curve in response to the grouting coefficient.

6. The method for non-destructive demolition of pile heads in complex strata according to claim 5, characterized in that, It also includes a nozzle protection method, the nozzle protection method comprising: Step 300: Determine the extrusion ratio by combining the remaining time and consolidation time; Step 301: Determine the extrusion pressure based on the extrusion ratio, pre-grouting volume, and depth coefficient; Step 302: Match the anti-clogging flow rate according to the extrusion pressure; Step 303: Update the filling rate curve in response to the anti-blocking flow rate.

7. The method for non-destructive demolition of pile heads in complex strata according to claim 6, characterized in that, The nozzle protection method also includes: Step 304: Extract the recovery rate based on the grouting pipe recovery curve, and determine the friction coefficient according to the pre-grouting amount; Step 305: Determine the recovery pressure based on the recovery rate and friction coefficient; Step 306: Update the extrusion pressure in response to the recovery pressure; Step 307: When the extrusion pressure is greater than the preset damage threshold, determine the upper limit of the rate by combining the friction coefficient and the preset damage threshold; Step 308: Update the grouting pipe recovery curve in response to the rate limit.

8. The method for non-destructive demolition of pile heads in complex strata according to claim 7, characterized in that, The nozzle protection method also includes: Step 309: When the consolidation time is less than the preset recycling threshold, retrieve the protection depth based on the consolidation time; Step 310: Match the protection speed according to the protection depth; Step 311: Determine the protection interval according to the protection speed; Step 312: Generate a nozzle protection curve by combining the protection speed and protection interval; Step 313: In response to the nozzle protection curve update pile jump command.

9. A construction system for non-destructive removal of pile heads in complex strata, characterized in that, include: The acquisition module is used to acquire soil parameters and pile images; A memory for storing a program for a non-destructive demolition method for pile heads in complex strata as described in any one of claims 1 to 8; The processor is the unit of memory that allows programs to be loaded and executed by the processor.

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