Reconstruction method of three-dimensional shape of ultra-deep high-pressure jet grouting piles in coastal soft soil foundation

Abstract

The present invention relates to the field of soft foundation treatment engineering, and provides a method for reconstructing the three-dimensional form of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations. Based on the theory of submerged free turbulent jet and the theory of soil destruction, a quantitative correlation mathematical model between the three-dimensional form of high-pressure jet grouting piles and the high-pressure jet grouting construction process parameters and the physical and mechanical property parameters of the soil is constructed; the values ​​of the high-pressure jet grouting construction process parameters in actual engineering applications are obtained, and the values ​​of the physical and mechanical property parameters of the soil corresponding to the high-pressure jet grouting reinforcement depth range in the actual engineering site are obtained; based on the Matlab image processing framework, a three-dimensional numerical reconstruction algorithm is developed to realize the reconstruction of the three-dimensional form of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations. The present invention can accurately reflect the changing characteristics of the pile body form with the burial depth, and can intuitively reconstruct the three-dimensional real form of the high-pressure jet grouting piles, and has the advantages of high intelligence, low cost, convenience and speed.

Description

Technical Field

[0001] The invention relates to the field of soft foundation treatment engineering, and in particular to a method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on a coastal soft soil foundation. Background Art

[0002] In coastal soft soil areas, the poor engineering properties of soft soil lead to problems such as insufficient bearing capacity, differential settlement or excessive cumulative deformation. In order to improve the bearing capacity of coastal soft soil foundations and reduce the probability of engineering disasters such as foundation pit collapse, embankment instability, building (structure) tilting, and road cracking, high-pressure rotary jet grouting technology is often used in engineering practice to reinforce the foundation. In foundation treatment projects using high-pressure rotary jet technology, the morphology of high-pressure rotary jet piles is one of the most important physical and mechanical parameters for quantitatively evaluating the reinforcement effect, regulating and optimizing the design parameters of the rotary jet process, and calculating the bearing capacity of high-pressure rotary jet piles and high-pressure rotary jet pile composite foundations.

[0003] At present, a variety of methods for predicting the morphology of high-pressure jet grouting piles have been proposed based on model tests, field tests, turbulent jet theoretical analysis, etc. These methods can be mainly divided into three categories: empirical methods, semi-empirical and semi-theoretical methods, and artificial intelligence methods. However, the above methods can only roughly predict the average diameter of the high-pressure jet grouting piles within the entire pile length, but cannot give the real three-dimensional morphology of the ultra-deep high-pressure jet grouting piles that change significantly along the depth. In engineering practice, the current prediction of the morphology of high-pressure jet grouting piles is heavily dependent on similar engineering experience or empirical models, resulting in large deviations in the prediction results and high uncertainty, which not only increases the risk of instability, damage, excessive deformation, and high environmental impact effects of the reinforcement project, but also increases the cost of the project. Therefore, the study of intelligent methods for reconstructing the three-dimensional morphology of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations has important engineering application value. Summary of the invention

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on a coastal soft soil foundation, the reconstruction method comprising:

[0006] (1) Based on literature research and field engineering experience, the key parameters affecting the three-dimensional morphology of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations are divided into high-pressure jet grouting construction process parameters and soil physical and mechanical property parameters;

[0007] (2) Based on the theory of submerged free turbulent jet and soil failure theory, a quantitative mathematical model is constructed to correlate the three-dimensional morphology of high-pressure jet grouting piles with the process parameters of high-pressure jet grouting and the physical and mechanical properties of soil.

[0008] (3) Obtaining the values ​​of high-pressure jet grouting construction process parameters in actual engineering applications can be obtained from the ultra-deep high-pressure jet grouting foundation treatment construction plan for coastal soft soil foundation;

[0009] (4) Obtain the values ​​of soil physical and mechanical property parameters corresponding to the depth range of high-pressure jet grouting reinforcement at the actual engineering site;

[0010] (5) Based on the quantitative correlation mathematical model and related parameters, Matlab program programming calculation is carried out to obtain a text file format file for storing data pairs of the high-pressure jet grouting pile diameter changing with the burial depth;

[0011] (6) Based on the Matlab image processing framework, a three-dimensional numerical reconstruction algorithm was developed to achieve the reconstruction of the three-dimensional shape of ultra-deep high-pressure jet grouting piles in coastal soft soil foundations.

[0012] Furthermore, in step (1), the high-pressure jet spraying construction process parameters include the jetting fluid flow rate, the number of nozzles, the nozzle diameter, the cement slurry water-cement ratio, the drilling and spraying rod rotation speed, the drilling and spraying rod diameter, the drilling and spraying rod lifting speed and the drilling and spraying rod lifting interval;

[0013] The physical and mechanical properties of soil include the proportion of fine soil particles with a particle size less than 0.075 mm, the average particle size of soil particles and the undrained shear strength of soil.

[0014] Furthermore, in step (2), the construction process of the quantitative correlation mathematical model is as follows:

[0015] (2-1) Establish a coordinate system with the center of the pile top as the origin of the coordinate system, the vertical direction of the pile as the vertical axis of the coordinate system, represented by z, with vertical downward as positive, and the horizontal direction of the pile as the horizontal axis of the coordinate system, represented by D jgc express;

[0016] (2-2) A theoretical relationship between the diameter of a high-pressure jet-jetted pile at any buried depth below the ground and the limit distance of soil erosion by high-speed jet flow is established. The theoretical relationship is expressed as formula ①:

[0017] D jgc (z) = d dp +2δ rf X lim (z) ①

[0018] Where: z is the vertical distance between the calculation point and the ground surface; D jgc (z) is the diameter of the high-pressure jet-jet pile at a depth z below the ground surface; d dp is the diameter of the drill rod; δ rf is the correction factor considering the actual working conditions; X lim (z) is the limit distance of soil erosion by high-speed jet at a depth z below the ground surface;

[0019] (2-3) Establish a theoretical relationship between the limit distance of high-speed jet erosion of soil at a depth z below the ground surface and the high-pressure jet grouting construction process parameters and soil physical and mechanical property parameters;

[0020] According to the theory of submerged free turbulent jet, after the high-speed jet is ejected from the nozzle of the drill spray rod, its speed decays linearly in the main section. When the high-speed jet speed decays to the minimum speed corresponding to the destruction of the soil, the distance of the high-speed jet erosion of the soil reaches the limit. Based on the high-pressure water jet test data and the empirical formula for calculating the critical destruction speed of the soil, the theoretical relationship between the limit distance of the high-speed jet erosion of the soil at a depth z below the surface and the high-pressure rotary spraying construction process parameters and the physical and mechanical properties of the soil can be obtained as shown in formula ②:

[0021]

[0022] Where: X lim (z) is the limit distance of high-speed jet erosion of soil at a depth z below the ground surface; Q is the jet flow rate; n is the number of nozzles; d0 is the nozzle diameter; M c (z) is the proportion of fine soil particles with a particle size less than 0.075 mm at the burial depth z; D 50 (z) is the average particle size of soil particles at the burial depth z; c u (z) is the undrained shear strength of the soil at the burial depth z; ρ w is the density of water, generally taken as 1000kg / m 3 ρ c is the density of cement, generally taken as 3150kg / m 3 ; η is the water-cement ratio of cement paste; μ w is the apparent viscosity of water, generally taken as 0.001Pa·s; p atm It is the standard atmospheric pressure value, and its value is 101.325kPa;

[0023] (2-4) Establish a theoretical relationship between the actual working condition correction coefficient and the high-pressure rotary grouting construction process parameters; Considering that in the actual high-pressure rotary grouting foundation treatment project, due to the upward movement and rotation of the nozzle, the duration of the high-speed jet ejected from the nozzle on the soil at a certain buried depth is limited, so the actual pile shape must be less than the limit distance of the high-speed jet erosion of the soil. Based on the regression analysis of the indoor model test data, the theoretical relationship between the actual working condition correction coefficient and the high-pressure rotary grouting construction process parameters is obtained, as shown in formula ③:

[0024]

[0025] Where: R s is the rotation speed of the drill rod; d dp is the diameter of the drill rod; vs is the lifting speed of the drill spray rod; n is the number of nozzles; ΔS t The lifting interval of the drilling and spraying rod is usually 5cm in engineering;

[0026] (2-5) Substituting formulas ② and ③ into formula ①, we can obtain the expression of the quantitative correlation mathematical model between the three-dimensional morphology of high-pressure jet grouting piles and the high-pressure jet grouting construction process parameters and the physical and mechanical properties of the soil.

[0027] Furthermore, the specific acquisition steps of step (4) are:

[0028] Firstly, the depth range of high-pressure rotary grouting reinforcement at the project site is obtained from the construction plan for ultra-deep high-pressure rotary grouting foundation treatment of coastal soft soil foundation. Then, the values ​​of the physical and mechanical properties of the soil corresponding to the burial depth of 0.1m at every high-pressure rotary grouting reinforcement depth at the project site are read from the geotechnical engineering investigation report.

[0029] Furthermore, the specific steps of step (5) are:

[0030] The first step is to set the calculation depth interval Δz to 0.1m at the beginning of the program, that is, the diameter of the high-pressure jet grouting pile is calculated every 0.1m along the depth direction;

[0031] The second step is to determine the total number of calculations N, which is related to the high-pressure jet grouting reinforcement depth l jgc , the calculation depth interval Δz is related, that is, N = l jgc / △z+1;

[0032] The third step is to set the initial value of the given burial depth z and the calculation ordinal number i to 0, that is, z = 0, i = 0;

[0033] Step 4: Add 1 to the value of the calculated ordinal number i, i=i+1;

[0034] Step 5: Input three high pressure jet spraying process parameters M c (z), D 50 (z), c u (z), at this time the value of z is zero, which corresponds to the physical and mechanical properties of the soil at the surface;

[0035] Step 6: Input eight high pressure jet spraying process parameters Q, n, d0, η, R s d dp 、v s , ΔS t ;

[0036] Step 7: Use formula ③ to calculate the correction factor δ considering the actual working conditions rf ;

[0037] Step 8: Use formula ② to calculate the limit distance X of soil erosion by high-speed jet flow at depth z below the ground surface. lim (z);

[0038] Step 9: Use formula ① to calculate the diameter D of the high-pressure jet grouting pile jgc (z);

[0039] Step 10, output (z,D jgc (z)) to a TXT file;

[0040] Step 11: Determine whether the calculation sequence number i is not greater than the total number of calculations N. If the result is true, set z = z + Δz.

[0041] Step 12: Repeat steps 4 to 11. If the result is false, the operation ends.

[0042] Furthermore, the specific steps of step (6) are:

[0043] The first step is to read the data in a text file format file for storing data pairs of high-pressure jet grouting pile diameters changing with burial depths;

[0044] The second step is to set the read data into an N×2 matrix;

[0045] The third step is to extract the buried depth z value and its corresponding high-pressure jet grouting pile radius, i.e. D jgc (z) / 2;

[0046] Step 4: Generate the parametric equation of the circle;

[0047] Step 5: Calculate the x and y coordinates of each point in the circle;

[0048] Step 6: Draw a three-dimensional cylinder;

[0049] Step 7: Draw the top round cap;

[0050] Step 8: Draw the bottom round cover;

[0051] Step 9: Add lighting effects;

[0052] Step 10. Set the file name and output the image.

[0053] The present invention has the following beneficial effects:

[0054] (1) The quantitative correlation mathematical model established by the present invention fully considers the influence of high-pressure jet grouting construction process parameters and soil physical and mechanical property parameters on the three-dimensional morphology of ultra-deep high-pressure jet grouting piles in coastal soft soil foundation, and its prediction results are more reasonable and reliable than traditional empirical methods;

[0055] (2) The three-dimensional morphology intelligent reconstruction method of the present invention can intelligently and efficiently dynamically display the true three-dimensional morphology of ultra-deep high-pressure rotary jet grouting piles that change with the burial depth. The process from data input to result display has a high degree of intelligence. The displayed three-dimensional morphology image ecological image can provide support for the design and construction optimization of high-pressure rotary jet grouting foundation treatment projects in coastal soft soil areas.

[0056] (3) The present invention can accurately reflect the changing characteristics of the pile body shape with the burial depth, and can intuitively reconstruct the three-dimensional true shape of the high-pressure rotary jet pile, and has the advantages of high intelligence, low cost, convenience and speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a flow chart of the three-dimensional morphology intelligent reconstruction method of the present invention.

[0058] Figure 2 Schematic diagram of the rectangular coordinate system in the quantitative association mathematical model.

[0059] Figure 3 This is a statistical diagram of the values ​​of the second type of key influencing parameters obtained in the embodiment.

[0060] Figure 4 This is a screenshot of the code snippet of the algorithm for intelligent reconstruction of the three-dimensional shape of ultra-deep high-pressure jet grouting piles in coastal soft soil foundations.

[0061] Figure 5 The three-dimensional shape of high-pressure jet-jet piles obtained by the method of the present invention is a certain coastal soft soil foundation treatment project.

[0062] Figure 6 The paper compares the predicted values ​​of the three-dimensional reconstruction method of high-pressure jet grouting pile morphology with the actual measured values ​​on site. DETAILED DESCRIPTION

[0063] The specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. It should be pointed out that the embodiments are only specific explanations of the invention and should not be regarded as limitations of the invention. The purpose of the embodiments is to enable those skilled in the art to better understand and reproduce the technical solutions of the present invention. The protection scope of the present invention shall still be based on the scope defined by the claims.

[0064] This embodiment is a single-tube high-pressure rotary grouting foundation reinforcement construction in a platform construction project for a vehicle depot on a coastal soft soil foundation, and illustrates in detail the detailed application and implementation process of the present invention.

[0065] like Figure 1 As shown, the present invention provides a method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on coastal soft soil foundation, comprising the following steps:

[0066] S1. Based on literature research and field engineering experience, the key parameters affecting the three-dimensional morphology of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations are classified; specifically, the key influencing parameters of the three-dimensional morphology of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations can be summarized into two categories: one is the high-pressure jet grouting construction process parameters (i.e., the first type of key influencing parameters), and the other is the soil physical and mechanical properties parameters (i.e., the second type of key influencing parameters); the first type of key influencing parameters mainly include the injection fluid flow rate, the number of nozzles, the nozzle diameter, the cement slurry water-cement ratio, the drilling and spraying rod rotation speed, the drilling and spraying rod diameter, the drilling and spraying rod lifting speed, and the drilling and spraying rod lifting interval; the second type of key influencing parameters mainly include the proportion of fine soil particles with a particle size less than 0.075 mm, the average particle size of soil particles, and the undrained shear strength of the soil;

[0067] S2, based on the theory of submerged free turbulent jet, soil failure theory and related empirical formulas, a quantitative correlation mathematical model between the three-dimensional morphology of high-pressure jet grouting piles and the first and second key influencing parameters is constructed;

[0068] The first step is to establish a rectangular coordinate system, such as Figure 2 As shown;

[0069] The second step is to establish a theoretical relationship between the diameter of the high-pressure jet-jet pile at any buried depth below the ground and the limit distance of the soil eroded by the high-speed jet, as shown in formula ①;

[0070] The third step is to establish the theoretical relationship between the limit distance of high-speed jet erosion of soil at the buried depth z below the surface and the first type of key influencing parameters and the second type of key influencing parameters, as shown in formula ②;

[0071] The fourth step is to establish a theoretical relationship between the actual working condition correction coefficient and the first type of key influencing parameters, as shown in formula ③;

[0072] Step 5: Substituting formulas ② and ③ into formula ①, the expression of the quantitative correlation mathematical model between the three-dimensional form of high-pressure jet grouting piles and the first type of key influencing parameters and the second type of key influencing parameters can be obtained;

[0073] S3, to obtain the value of the first type of key influencing parameters in actual engineering applications; according to the single-tube high-pressure jet grouting foundation reinforcement construction plan in the construction of a platform on the upper cover of a coastal soft soil foundation vehicle depot, Q = 2.5 × 10 -3 m 3 / s, n = 2, d0 = 1.6 mm, η = 1.25, R s =20rpm, d dp =60mm,v s =6.6mm / s, △S t =5cm;

[0074] S4, obtain the values ​​of the second type of key influencing parameters corresponding to the depth range of high-pressure rotary grouting reinforcement at the actual engineering site; first, obtain the high-pressure rotary grouting reinforcement depth range of 8m at the engineering site from the single-tube high-pressure rotary grouting foundation reinforcement construction plan in the construction project of a platform on the upper cover of a coastal soft soil vehicle depot, and then read the values ​​of the second type of key influencing parameters corresponding to the depth range of high-pressure rotary grouting reinforcement at the engineering site every 0.1m of burial depth from the geotechnical engineering survey report, such as Figure 3 As shown;

[0075] S5, based on the above quantitative correlation mathematical model and related parameters, Matlab program programming calculation is carried out to obtain a text file format file for storing data pairs of high-pressure jet grouting pile diameter changes with burial depth; the specific steps are as follows:

[0076] The first step is to set the calculation depth interval Δz to 0.1m at the beginning of the program, that is, the diameter of the high-pressure jet grouting pile is calculated every 0.1m along the depth direction;

[0077] The second step is to determine the total number of calculations.

[0078] The third step is to set the initial value of the given burial depth z and the calculation ordinal number i to 0, that is, z = 0, i = 0;

[0079] Step 4: Add 1 to the value of the calculated ordinal number i, i=i+1;

[0080] Step 5: Input three first-class key influencing parameters M c (z) z＝0 =85%, D 50 (z) z＝0 =0.023mm, c u (z) z＝0 =39.78 kPa, at which point the value of z is zero, corresponding to the physical and mechanical properties of the soil at the surface;

[0081] Step 6: Input eight first-class key influencing parameters Q = 2.5 × 10 -3 m 3 / s, n = 2, d0 = 1.6 mm, η = 1.25, R s =20rpm, d dp =60mm,v s =6.6mm / s, △S t =5cm;

[0082] Step 7: Use formula ③ to calculate the correction coefficient δ considering the actual working conditions rf =0.16;

[0083] Step 8: Use formula ② to calculate the limit distance X of high-speed jet erosion of soil at depth z = 0 below the surface. lim (z) z＝0 =2.36m;

[0084] Step 9: Use formula ① to calculate the diameter D of the high-pressure jet grouting pile jgc (z) z＝0 =0.81m;

[0085] Step 10. Output (0,0.81) to TXT file;

[0086] Step 11: Determine that the calculation coefficient i=1 is not greater than the total number of calculations N=81, then let z=z+Δz=0.1m,

[0087] Step 12: Repeat steps 4 to 11 until the operation ends when i>N.

[0088] S6, based on the Matlab image processing framework, develop a 3D numerical reconstruction algorithm (partial code snippet as Figure 4 As shown in the figure, the intelligent reconstruction of the three-dimensional shape of ultra-deep high-pressure jet grouting piles in coastal soft soil foundation is realized; the code architecture of the developed three-dimensional numerical reconstruction algorithm is as follows:

[0089] The first step is to read the data in a text file format file for storing data pairs of high-pressure jet grouting pile diameters changing with burial depths;

[0090] The second step is to set the read data into a 81×2 matrix;

[0091] The third step is to extract the buried depth z value and its corresponding high-pressure jet grouting pile radius (i.e. D jgc (z) / 2);

[0092] Step 4: Generate the parametric equation of the circle;

[0093] Step 5: Calculate the x and y coordinates of each point in the circle;

[0094] Step 6: Draw a three-dimensional cylinder;

[0095] Step 7: Draw the top round cap;

[0096] Step 8: Draw the bottom round cover;

[0097] Step 9: Add lighting effects;

[0098] Step 10, set the file name and output the image, such as Figure 5 shown. Figure 5The three-dimensional morphology of high-pressure jet grouting piles in a platform construction project for the development of a vehicle depot on a soft soil foundation on the coast obtained by the intelligent reconstruction method of the present invention is compared with the three-dimensional morphology of the piles measured on site. Figure 6 As shown, from Figure 6 It can be clearly seen that the predicted value of the reconstruction method of the present invention is basically consistent with the actual measured value on site. The accuracy of the intelligent reconstruction method of the three-dimensional morphology of ultra-deep high-pressure rotary jet grouting piles in coastal soft soil foundation of the present invention is relatively reliable. It can also intelligently and efficiently dynamically display the real three-dimensional morphology of ultra-deep high-pressure rotary jet grouting piles that change with the burial depth. The process from data input to result display has a high degree of intelligence. The displayed three-dimensional morphological image ecological image can provide support for the design and construction optimization of high-pressure rotary jet grouting foundation treatment projects in coastal soft soil areas.

[0099] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0100] It should be noted that the technical features not described in detail in the present invention can be implemented by any existing technology.

Claims

1. A method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on coastal soft soil foundation, characterized in that: The reconstruction method comprises: (1) Based on literature research and field engineering experience, the key parameters affecting the three-dimensional morphology of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations are divided into high-pressure jet grouting construction process parameters and soil physical and mechanical property parameters; (2) Based on the theory of submerged free turbulent jet and soil failure theory, a quantitative mathematical model is constructed to correlate the three-dimensional morphology of high-pressure jet grouting piles with the process parameters of high-pressure jet grouting and the physical and mechanical properties of soil. (3) Obtain the values ​​of high-pressure jet grouting construction process parameters in actual engineering applications; (4) Obtain the values ​​of soil physical and mechanical property parameters corresponding to the depth range of high-pressure jet grouting reinforcement at the actual engineering site; (5) Based on the quantitative correlation mathematical model and related parameters, Matlab program programming calculation is carried out to obtain a text file format file for storing data pairs of the high-pressure jet grouting pile diameter changing with the burial depth; (6) Based on the Matlab image processing framework, a three-dimensional numerical reconstruction algorithm was developed to achieve the three-dimensional shape reconstruction of ultra-deep high-pressure jet grouting piles on coastal soft soil foundations; In step (2), the construction process of the quantitative correlation mathematical model is as follows: (2-1) Establish a coordinate system with the center of the pile top as the origin of the coordinate system, the vertical direction of the pile as the vertical axis of the coordinate system, represented by z, with vertical downward as positive, and the horizontal direction of the pile as the horizontal axis of the coordinate system, represented by D jgc express; (2-2) A theoretical relationship between the diameter of a high-pressure jet-jetted pile at any buried depth below the ground and the limit distance of soil erosion by high-speed jet flow is established. The theoretical relationship is expressed as formula ①: D jgc (z)=d dp +2δ rf X lim (z) ① Where: z is the vertical distance between the calculation point and the ground surface; D jgc (z) is the diameter of the high-pressure jet-jet pile at a depth z below the ground surface; d dp is the diameter of the drill rod; δ rf is the correction factor considering the actual working conditions; X lim (z) is the limit distance of soil erosion by high-speed jet at a depth z below the ground surface; (2-3) Establish a theoretical relationship between the limit distance of high-speed jet erosion of soil at a depth z below the ground surface and the high-pressure jet grouting construction process parameters and soil physical and mechanical property parameters; According to the theory of submerged free turbulent jet, after the high-speed jet is ejected from the nozzle of the drill spray rod, its speed decays linearly in the main section. When the high-speed jet speed decays to the minimum speed corresponding to the destruction of the soil, the distance of the high-speed jet erosion of the soil reaches the limit. Based on the high-pressure water jet test data and the empirical formula for calculating the critical destruction speed of the soil, the theoretical relationship between the limit distance of the high-speed jet erosion of the soil at a depth z below the surface and the high-pressure rotary spraying construction process parameters and the physical and mechanical properties of the soil can be obtained as shown in formula ②: Where: X lim (z) is the limit distance of high-speed jet erosion of soil at a depth z below the ground surface; Q is the jet flow rate; n is the number of nozzles; d0 is the nozzle diameter; M c (z) is the proportion of fine soil particles with a particle size less than 0.075 mm at the burial depth z; D 50 (z) is the average particle size of soil particles at the burial depth z; c u (z) is the undrained shear strength of the soil at the burial depth z; ρ w is the density of water; ρ c is the cement density; η is the water-cement ratio of cement paste; μ w is the apparent viscosity of water; p atm is the standard atmospheric pressure value; (2-4) Establish a theoretical relationship between the actual working condition correction coefficient and the high-pressure rotary grouting construction process parameters; Considering that in the actual high-pressure rotary grouting foundation treatment project, due to the upward movement and rotation of the nozzle, the duration of the high-speed jet ejected from the nozzle on the soil at a certain buried depth is limited, so the actual pile shape must be less than the limit distance of the high-speed jet erosion of the soil. Based on the regression analysis of the indoor model test data, the theoretical relationship between the actual working condition correction coefficient and the high-pressure rotary grouting construction process parameters is obtained, as shown in formula ③: Where: R s is the rotation speed of the drill rod; d dp is the diameter of the drill rod; v s is the lifting speed of the drill spray rod; n is the number of nozzles; ΔS t Lifting intervals for drilling and spraying booms; (2-5) Substituting formulas ② and ③ into formula ①, we can obtain the expression of the quantitative correlation mathematical model between the three-dimensional morphology of high-pressure jet grouting piles and the high-pressure jet grouting construction process parameters and the physical and mechanical properties of the soil.

2. The method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on coastal soft soil foundation according to claim 1 is characterized in that: In step (1), the high-pressure jet spraying construction process parameters include the jetting fluid flow rate, the number of nozzles, the nozzle diameter, the cement slurry water-cement ratio, the drilling and spraying rod rotation speed, the drilling and spraying rod diameter, the drilling and spraying rod lifting speed and the drilling and spraying rod lifting interval; The physical and mechanical properties of soil include the proportion of fine soil particles with a particle size less than 0.075 mm, the average particle size of soil particles and the undrained shear strength of soil.

3. The method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on coastal soft soil foundation according to claim 1 is characterized in that: The specific acquisition steps of step (4) are: Firstly, the depth range of high-pressure rotary grouting reinforcement at the project site is obtained from the construction plan for ultra-deep high-pressure rotary grouting foundation treatment of coastal soft soil foundation. Then, the values ​​of the physical and mechanical properties of the soil corresponding to the burial depth of 0.1m at every high-pressure rotary grouting reinforcement depth at the project site are read from the geotechnical engineering investigation report.

4. The method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on coastal soft soil foundation according to claim 1 is characterized in that: The specific steps of step (5) are: The first step is to set the calculation depth interval Δz to 0.1m at the beginning of the program, that is, the diameter of the high-pressure jet grouting pile is calculated every 0.1m along the depth direction; The second step is to determine the total number of calculations N, which is related to the high-pressure jet grouting reinforcement depth l jgc , the calculation depth interval Δz is related, that is, N = l jgc / △z+1; The third step is to set the initial value of the given burial depth z and the calculation number i to 0, that is, z = 0, i = 0; Step 4: Add 1 to the value of the calculated ordinal number i, i=i+1; Step 5: Input three high pressure jet spraying process parameters M c (z), D 50 (z), c u (z), at this time the value of z is zero, which corresponds to the physical and mechanical properties of the soil at the surface; Step 6: Input eight high pressure jet spraying process parameters Q, n, d0, η, R s ,d dp 、v s , ΔS t ; Step 7: Use formula ③ to calculate the correction factor δ considering the actual working conditions rf ; Step 8: Use formula ② to calculate the limit distance X of soil erosion by high-speed jet flow at depth z below the ground surface. lim (z); Step 9: Use formula ① to calculate the diameter D of the high-pressure jet grouting pile jgc (z); Step 10: Output (z,D jgc (z)) to a TXT file; Step 11: Determine whether the calculation sequence number i is not greater than the total number of calculations N. If the result is true, set z = z + Δz. Step 12: Repeat steps 4 to 11. If the result is false, the operation ends.

5. The method for reconstructing the three-dimensional shape of ultra-deep high-pressure jet grouting piles on coastal soft soil foundation according to claim 1 is characterized in that: The specific steps of step (6) are: The first step is to read the data in a text file format file for storing data pairs of high-pressure jet grouting pile diameters changing with burial depths; The second step is to set the read data into an N×2 matrix; The third step is to extract the buried depth z value and its corresponding high-pressure jet grouting pile radius, i.e. D jgc (z) / 2; Step 4: Generate the parametric equation of the circle; Step 5: Calculate the x and y coordinates of each point in the circle; Step 6: Draw a three-dimensional cylinder; Step 7: Draw the top round cap; Step 8: Draw the bottom round cover; Step 9: Add lighting effects; Step 10. Set the file name and output the image.

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