CN116695800B - A method for detecting and predicting the horizontal bearing capacity of offshore wind power piles - Google Patents

Abstract

The invention relates to a detection and prediction method for horizontal bearing capacity of an offshore wind power pile, which comprises the following steps: s1, setting a model box and determining a model pile; s2, setting a pile installation position and a horizontal plastic deformation zone, and setting a measuring line and a measuring point; s3, filling test soil into the model box; setting a CPTU measurement system and a CPTU penetration system; s4, installing a model pile, and setting a deformation measuring mechanism; s5, estimating the ultimate horizontal bearing capacity F of the model pile _max Setting a horizontal force load F ₁ ~F _M Sequentially applying F to the model piles ₁ ~F _M And CPTU testing is performed at the measurement point of one line until F _X+1 When the pile displacement is overlarge, F is obtained ₁ ~F _X CPTU measurement data and pile body deformation after soil for lower test is disturbed; s6, obtaining F ₁ ~F _X P-y of model pile under horizontal force load of each level _（z） Curve to obtain p-y suitable for rigid pile failure mode _（z） A curve; s7, according to the p-y suitable for the damage mode of the rigid piles _（z） And (3) calculating the horizontal bearing capacity of the offshore wind turbine pile by combining the curves with the related specifications.

Description

A method for detecting and predicting the horizontal bearing capacity of offshore wind power piles

Technical field

The invention relates to the field of geotechnical engineering, and in particular to a method for detecting and predicting the horizontal bearing capacity of offshore wind power piles.

Background technique

Under the development trend of developing and utilizing green energy, offshore wind power, as a clean energy source, has irreplaceable advantages such as high energy efficiency and small occupation of land resources, and is developing rapidly around the world. Offshore wind turbines often use large-diameter rigid pile foundations. Compared with onshore pile foundations, offshore wind turbine pile foundations bear greater wind and wave loads in the horizontal direction. Horizontal bearing capacity is a key factor affecting the safety of offshore wind turbine pile foundations.

Currently, common methods for evaluating the horizontal bearing capacity of offshore wind power pile foundations include theoretical methods based on foundation parameters, design methods, and on-site horizontal pile push load tests. Theoretical methods include using the hole expansion theory to estimate the soil resistance distribution around the pile and then calculate the horizontal bearing capacity of the pile. However, the hole expansion theory requires such factors as the undrained shear strength, Poisson's ratio, and modulus of the soil in the plastic zone around the pile. Calculation parameters such as these are difficult to obtain directly and are mostly determined by empirical formulas, resulting in low reliability of theoretical calculation results; the design method is mainly based on the horizontal bearing capacity-displacement curve recommended in the API specification and based on the experimental results of small-diameter flexible pile push piles. (i.e., p-y curve) to calculate the bearing capacity, but offshore wind power piles are rigid piles. This p-y curve does not match the failure mode of rigid piles, and the design calculation results are inaccurate. However, the on-site horizontal push pile load test of offshore wind power pile foundations is limited by equipment and cost. The test piles used are quite different from the actual pile foundations, and the cost is high. Especially for large-diameter piles, the push pile load test is more difficult to use.

Cone penetration test (CPT) is an important in-situ testing technology in the field of geotechnical engineering. It is currently mainly used for soil layer division, site liquefaction identification, physical and mechanical parameter estimation of foundation soil layers, and foundation bearing capacity. Assessment, pile foundation bearing capacity estimation, etc. Among them, piezocone penetration test (CPTU) has become an important reference for the design parameters of offshore wind power pile foundation engineering. It has the advantages of intuitiveness, speed and data continuity, and can directly obtain the soil layer around the pile foundation on site. The cone tip resistance, side wall friction and other indicators directly reflect the physical and mechanical properties of the soil around the pile.

In the existing technology, due to the complex offshore environment and limitations of loading equipment, it is often difficult to conduct in-situ horizontal bearing capacity tests for offshore wind power pile foundations. The data obtained are also difficult to analyze due to too many influencing factors. It is difficult to accurately obtain the horizontal bearing capacity performance of offshore wind power pile foundations

Contents of the invention

In view of the shortcomings of the prior art mentioned above, the technical problem to be solved by the present invention is to provide a method for detecting and predicting the horizontal bearing capacity of offshore wind power piles, which can conveniently, accurately and systematically evaluate the level of rigid pile foundations by adopting a model test method. Carrying capacity.

In order to achieve the above objectives, the present invention provides a method for detecting and predicting the horizontal bearing capacity of offshore wind power piles, which includes the following steps:

S1. Set up the model box, design the model test similarity ratio according to the prototype working conditions, and determine the size of the model pile, including the diameter D of the model pile.

S2. Set a pile installation position in the model box, set a horizontal plastic deformation zone in front of the pile installation position, and set N measuring lines passing through the center of the pile installation position in front of the pile installation position. Set a At least one measuring point, the measuring point is located in the horizontal plastic deformation zone, and the distance H ₁ between the center of the measuring point closest to the pile installation position and the center of the pile installation position is 1D~1.5D.

S3. Fill the model box with test soil in accordance with the specified requirements; set up the CPTU measurement system and CPTU penetration system.

S4. Install the model pile at the pile installation position. The model pile is inserted into the test soil. The model pile is equipped with a deformation measuring mechanism for detecting the deformation of the pile body.

S5. Estimate the ultimate horizontal bearing capacity F _max of the model pile. According to the size of F _max , set M level horizontal loads from small to large and record them as F ₁ ~ F _M respectively, N ≥ M, F _M ≥ F _max ; use classification The loading method is to apply forward horizontal force loads F ₁ to F _M to the model piles in sequence. After each load is applied and stabilized, the CPTU probe of the CPTU measurement system is used to conduct a CPTU test at the measurement point of a measurement line. When _{the horizontal} force load _F The measured ultimate horizontal bearing capacity of the model pile is recorded as F _measured ; the CPTU measurement data after the test soil was disturbed under each horizontal force load F _{1 ~ F} The deformation of the pile body of the model pile under F _X.

S6. _{According to the magnitude of the horizontal force load at each level from F 1 to F} The total pile side soil resistance p and the horizontal displacement y _(z) of the model pile at each depth z are combined with the total pile side soil resistance p and the horizontal displacement y _(z) to obtain the py _(z) curve of the model pile, so that Obtain the py _(z) curve suitable for the failure mode of rigid piles.

S7. Based on the obtained py _(z) curve suitable for the failure mode of rigid piles and combined with relevant specifications, calculate the horizontal bearing capacity of offshore wind power piles.

Further, in the step S1, the prototype working condition is the large-diameter steel pipe pile foundation of the offshore wind turbine, and it is the rigid pile deformation and failure mode.

Further, in step S2, the horizontal plastic deformation zone is obtained based on the prediction of the failure mode of the rigid pile.

Further, in step S2, the straight line passing through the center of the pile installation position and along the front-to-back direction is the horizontal load positioning line, the angles between adjacent survey lines are equal, and the N survey lines are symmetrically distributed with respect to the horizontal load positioning line.

Further, in step S2, each measuring line is provided with measuring points at 5.5D and 10.5D from the center of the pile installation position.

Further, in step S3, the test soil is prepared according to the geotechnical test method standard GB/T 50123-2019, and the filling soil is evenly dense and fully saturated.

Further, in step S4, the deformation measurement mechanism includes strain gauges arranged on both sides of the model pile, or distributed optical fiber sensors arranged on both sides of the model pile.

Further, the step S6 also includes: calculating the pile body bending moment distribution of the model pile according to the pile body deformation measured by the deformation measuring mechanism, determining the inverse bending point of the model pile, and observing the deformation and failure mode of the model pile.

Further, in step S6, the total pile side soil resistance p is calculated as follows: through the pile side soil resistance calculation formula established based on the hole expansion theory, first calculate the pile side soil resistance p (z, y) at each depth z ), , , , , , , where y is the horizontal displacement of the model pile at the calculation point, converted by the deformation of the pile body of the model pile; μ is the friction coefficient between the pile and soil; σ ₀ is the static soil pressure at the calculation point; C _u is the inconsistency of the soil at the calculation point. Drainage shear strength; r ₀ is the radius of the model pile; K is the lateral soil stress coefficient at the calculation point; γ is the saturated weight of the soil around the pile; E is the deformation modulus of the soil at the calculation point; ν is the soil at the calculation point The Poisson's ratio _of Total pile side soil resistance , z _max is the depth of penetration of the model pile into the soil.

Further, step S6 also includes: detecting and predicting the horizontal bearing capacity of offshore wind power piles based on the rigid pile failure mode through comparative analysis of the total pile side soil resistance calculation results and the measured ultimate horizontal bearing capacity of the model pile.

As mentioned above, the detection and prediction method related to the present invention has the following beneficial effects:

1) Through the theoretical design simulation test of the rigid pile failure mode, the horizontal bearing capacity of the simulated pile under graded load is used to detect and predict the horizontal bearing capacity of the actual prototype pile foundation. Compared with the field test method, the cost is low and the influencing factors can be It can conveniently, accurately and systematically detect and predict the horizontal bearing capacity of pile foundations, avoiding the difficulty of on-site testing at sea. According to the large diameter rigid pile design model, based on the total pile side soil resistance calculated through measured CPTU data and the measured pile body horizontal displacement, the accurate relationship between the total pile side soil resistance p and the pile body horizontal displacement y _(z) can be obtained, that is py _(z) curve, thereby improving the prediction accuracy of the horizontal bearing capacity of large-diameter rigid piles for offshore wind power. Combined with relevant specifications, the horizontal bearing capacity of offshore wind power piles can be calculated.

2) Combining experimental test data with theoretical calculations, it is possible to determine the position of the pile foundation's stress inflection point, the resistance distribution of the pile side soil, and the pile foundation's ultimate bearing capacity, etc., and to fully evaluate the deformation and damage of the pile foundation under the action of horizontal force loads. process for research.

3) CPTU data has high accuracy and large quantity, which can directly reflect the properties of the soil and facilitate the detection and prediction of the horizontal bearing capacity of pile foundations.

Description of the drawings

Figure 1 is a schematic flow chart of the method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to the present invention.

Figure 2 is a schematic diagram of measuring lines and measuring points in the present invention.

Figure 3 is a schematic diagram of measuring at a measuring point of a certain measuring line in the present invention.

Detailed ways

The implementation of the present invention is described below with specific embodiments. Those familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to coordinate with the content disclosed in the specification and are for the understanding and reading of those familiar with this technology. They are not used to limit the conditions for the implementation of the present invention. Therefore, it has no technical substantive significance. Any structural modifications, changes in proportions or adjustments in size shall still fall within the scope of the invention disclosed without affecting the efficacy and purpose of the invention. Within the scope of technical content. At the same time, terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for convenience of description and are not used to limit the scope of the present invention. , changes or adjustments in their relative relationships, provided there is no substantial change in the technical content, shall also be deemed to be within the scope of the present invention.

Referring to Figures 1 to 3, the present invention provides a method for detecting and predicting the horizontal bearing capacity of offshore wind power piles, which includes the following steps:

S1. Set up the model box, and determine the size of the model pile 1, including the diameter D of the model pile 1, based on the similarity ratio of the prototype working condition design model test. Among them, the large-diameter steel pipe pile foundation of offshore wind turbines showing the deformation and failure mode of rigid piles is used as the prototype working condition, and model pile 1 is a rigid pile. The size of the model box can be selected according to the actual situation.

S2. Set a pile installation position for installing the model pile 1 in the model box. A horizontal plastic deformation zone is provided in front of the pile installation position, and N measuring lines 2 passing through the center of the pile installation position are set in front of the pile installation position. The measuring line 2 passes through the horizontal plastic deformation zone, and at least one measuring point 3 is set on each measuring line 2. The measuring point 3 is located in the horizontal plastic deformation zone, and the measuring point 3 closest to the pile installation position is as close as possible to the pile. The distance _H1 between the center of the model pile 1 at the installation position and the center of the pile installation position satisfies 1D~1.5D. The pile installation position is at a suitable position of the model box, preferably at the middle position in the left and right directions of the model box. The horizontal plastic deformation zone is the area where plastic deformation of the soil on the side of the pile occurs when the model pile 1 installed at the pile installation position is subjected to a forward horizontal force load F.

In this embodiment, the horizontal plastic deformation zone can be predetermined based on the rigid pile failure mode and the size of the model pile 1. The horizontal plastic deformation zone is a fan-shaped area, and its center is located at the center of the pile installation position, that is, located at the installed model. on the central axis of pile 1. Of course, the horizontal plastic deformation zone can also be determined using existing appropriate methods.

Referring to Figure 2, preferably, in this embodiment, the number of survey lines 2 is N=5, the angles between adjacent survey lines 2 are equal, and the straight line passing through the center of the pile installation position and along the front and back direction is the horizontal load positioning line. The horizontal plastic deformation zone is symmetrical about the horizontal load positioning line. Preferably, the five measuring lines 2 are symmetrically distributed about the horizontal load positioning line, that is, one measuring line 2 coincides with the horizontal load positioning line, and the measuring line 2 is marked as L5. Two measurements are set on both sides of the horizontal load positioning line. The two outer measuring lines 2 are respectively recorded as L1 and L2, which are respectively close to the two radial sides of the sector-shaped horizontal plastic deformation zone. The angle between the two measuring lines 2 of L1 and L2 is 120°, and L1 and L5 The two survey lines 2 are L3 survey line 2, and the two survey lines 2 of L2 and L5 are L4 survey line 2. The angle between adjacent survey lines 2 is 30°.

Referring to Figure 2, preferably, in this embodiment, each measuring line 2 is provided with three measuring points 3, corresponding to any measuring line 2 numbered Li, and the three measuring points 3 on it are respectively marked as P _i-1 , P _i-2 and P _i-3 , P _i-1 measuring point 3 is closest to the center of the pile installation position, and the centers of the three measuring points 3 of P _i-1 , P _i-2 and P _i-3 are The distance distribution of the pile installation centers is H ₁ , H ₂ and H ₃ , H ₁ is 1.5D, H ₂ and H ₃ are 5.5D and 10.5D respectively.

S3. Fill the model box with test soil according to the specified requirements. Specifically, prepare the test soil according to the geotechnical test method standard GB/T50123-2019. The filling soil should be evenly dense and fully saturated to ensure that the test soil can simulate the actual offshore wind power piles. Soil foundation. Set up a CPTU measurement system and a CPTU penetration system. The CPTU measurement system has a CPTU probe 4. Preferably, the CPTU measurement system also includes a positioning mechanism, which can drive the CPTU probe 4 to move above each measurement point 3 through the positioning mechanism under computer control. The CPTU penetration system can penetrate the CPTU probe 4 downward into the filled test soil. Both the CPTU measurement system and the CPTU penetration system can adopt existing structures.

Preferably, in this step, the CPTU probe 4 of the CPTU measurement system is penetrated into the test soil through the CPTU penetration system and measured to obtain the CPTU benchmark parameters of the test soil without pile foundation disturbance. The CPTU benchmark parameters include the cone For the three indicators of tip resistance, side wall friction and pore water pressure, during the penetration measurement process of CPTU probe 4, the change curve of each indicator with penetration depth can be obtained. Among them, the measurement of the CPTU benchmark parameters can be before the model pile 1 is driven, or after the model pile 1 is driven, and the measured position after that must meet the distance requirements. The distance is greater than 10.5D and is not affected by the driving of model pile 1. The measurement is carried out at a position far away from the pile installation position, and the CPTU probe 4 is penetrated to a certain depth through the CPTU penetration system to complete a measurement. The measurement data obtained by the CPTU probe 4 is recorded as the CPTU benchmark parameter.

S4. Install the model pile 1 at the pile installation position. The model pile 1 is inserted into the test soil. The model pile 1 is provided with a deformation measuring mechanism for detecting the deformation of the pile body. The deformation measurement mechanism can use strain gauges, and strain gauges are provided on both front and rear sides of the model pile 1, and the deformation amount of the pile body is determined through the strain gauges on both sides. The deformation measurement mechanism can also use distributed optical fiber sensors. Distributed optical fiber sensors are installed on both front and rear sides of the model pile 1. The deformation amount of the pile body is determined through the distributed optical fiber sensors on both sides.

S5. Estimate the ultimate horizontal bearing capacity F _max of the model pile. According to the size of F _max , set M level horizontal loads from small to large and record them as F ₁ ~F _M respectively, N≥M, F _M ≥F _max , where The interval difference between two adjacent levels of horizontal force load can be set according to the size of F _max and the condition of model pile 1; using a graded loading method, forward horizontal force loads F ₁ ~ F _M are sequentially applied to model pile 1 in sequence, and the horizontal force is The force load acts on the appropriate part of the model pile 1 above the surface of the test soil. After each load is applied and stabilized, the CPTU measurement system and the CPTU penetration system are used to conduct the CPTU test at measurement point 3 of a measurement line 2 (during the test The load is maintained) until the X+1 horizontal load F is applied. When X ₊ 1, the phenomenon of excessive pile displacement occurs. The horizontal displacement of the surface exceeds the maximum value required by the design. For details, please refer to the specification "Technical Regulations for Experimental Testing of Water Transportation Engineering Foundations (JTS237-2017)". At this time, it means that the horizontal load F _X+1 has exceeded the actual limit of model pile 1 For _the horizontal bearing capacity _, the X _- level horizontal force load _F At _the same time, the CPTU measurement data after the test soil was disturbed under each horizontal force load F _{1 ~ F} .

In this embodiment, specifically, when any horizontal force load F _i is applied, 1≤i≤X, three Pi _-1 , Pi _-2 and Pi _-3 on the Li measurement line 2 are selected. Measure at measuring point 3. The CPTU probe 4 penetrates into the test soil at measuring point 3 to obtain CPTU measurement data. The CPTU measurement data includes three indicators: cone tip resistance, side wall friction resistance and pore water pressure. The CPTU probe 4. During the penetration measurement process, the variation curve of each indicator with penetration depth can be obtained. Moreover, during the penetration measurement process of CPTU probe 4, when the data measured by CPTU probe 4 no longer changes, or there is a slight change but the change is within the specified range, it is said that the underlying soil layer no longer changes, that is, it exceeds If the depth of plastic deformation of the soil on the side of the pile is found, the penetration of CPTU probe 4 will be stopped. Preferably, the data measured by the CPTU probe 4 can also be compared with the CPTU reference parameters in step S3 to determine the condition of the soil layer, determine the depth of plastic deformation there, and determine whether to stop penetration. The penetration depth of CPTU probe 4 at P _i-1 measurement point 3 is at least approximately 70% of the depth of model pile 1 in the soil. Finally, the CPTU measurement data corresponding to the horizontal force load F _i is obtained, and the pile deformation corresponding to the horizontal force load F _i is obtained through the deformation measurement mechanism.

S6. _According to the _{magnitude of the horizontal force load at each level from F 1 to} F The total pile side soil resistance p of the soil and the horizontal displacement y _(z) of the model pile 1 at each depth z are combined with the total pile side soil resistance p and the horizontal displacement y _(z) to fit the py _(z) of the model pile 1 ₎ curve, thereby obtaining the py _(z) curve suitable for the failure mode of rigid piles. At the same time, the position of the force reverse bending point of model pile 1 under the action of horizontal force loads at all levels can also be obtained.

In this step, specifically, the way to obtain the position of the stressed reverse bending point is: based on the deformation of the pile body measured by the deformation measuring mechanism, calculate the bending moment distribution of the pile body of the model pile 1, and determine the reverse bending of the model pile 1 point to observe the deformation and failure mode of model pile 1.

In this step, through the calculation formula of pile side soil resistance established based on hole expansion theory, the pile side soil resistance p (z, y) at each depth z is calculated, , , , , , , where y is the horizontal displacement of model pile 1 at the depth z, converted from the pile deformation of model pile 1, μ is the friction coefficient between pile and soil, σ ₀ is the static earth pressure at the calculation point, and C _u is Calculate the undrained shear strength of the soil at the calculation point, r ₀ is the radius of model pile 1; K is the lateral soil stress coefficient at the calculation point, γ is the saturated weight of the soil around the pile, and E is the deformation modulus of the soil at the calculation point , ν is the Poisson’s ratio of the soil at the calculation point. The relevant parameters μ, Cu, K, E and ν of the test soil are determined based on the CPTU measurement data and relevant specifications of the P _i-1 measurement point 3 closest to the pile installation position. Specifically, Cu, K and E are determined by P _i-1 The CPTU measurement data of measuring point 3 is calculated by referring to the corresponding recommended calculation formula in the "Technical Regulations for Bore Pressure Static Penetration Testing" (TCCES 1-2017). μAccording to CPTU measurement data and the recommended design parameters in Table 6.4.3-1 Pile-Soil in the "Recommended Practice for Planning, Design and Construction of Offshore Fixed Platforms - Working Stress Design Method" (SY/T 10030-2018), the design specification for offshore wind power platforms Selection of tangent value of friction angle. Poisson's ratio ν can be selected through the recommended value in Section 10.2.5 of the "Code for Geotechnical Engineering Investigation" (GB50021-2001, 2009 edition). R _p2 is the radius of the fan-shaped horizontal plastic deformation zone actually produced in the soil after the pile is horizontally displaced, which can be calculated from the CPTU measurement data at different measurement points 3. Through the above calculation formula of pile side soil resistance established based on hole expansion theory, the distribution of pile side soil resistance at each depth of model pile 1 under the action of horizontal force load can be obtained. By integrating along the depth, the total pile side soil resistance of model pile 1 can be obtained. soil resistance , z _max is the penetration depth of model pile 1. The total soil resistance on the pile side of model pile 1 is the theoretically calculated value of the horizontal bearing capacity of model pile 1. _Moreover , by comparing and _analyzing the calculated results of the total _pile side soil resistance p when the horizontal force load F Verify whether the theoretically calculated horizontal bearing capacity value (total pile side soil resistance p) is reasonable.

S7. Based on the obtained py _(z) curve suitable for the failure mode of rigid piles and combined with relevant specifications, calculate the horizontal bearing capacity of offshore wind power piles. Specifically, when it is necessary to predict the horizontal bearing capacity of an offshore wind power pile, according to the obtained py _(z) curve of the rigid pile failure mode, each depth corresponds to a py _(z) curve, combined with "API RP 2A WSD"" or the method in relevant specifications such as "Recommended Practice for Planning, Design and Construction of Offshore Fixed Platforms - Working Stress Design Method" (SY/T 10030-2018), taking the maximum horizontal displacement of the pile at the soil surface allowed by the design as the initial Conditions are calculated iteratively to obtain the total lateral soil resistance of the rigid pile when the soil surface reaches the maximum horizontal displacement. The total lateral soil resistance is the horizontal bearing capacity of the offshore wind power pile.

Through the theoretical calculation value of the horizontal bearing capacity of model pile 1, and then according to the model test similarity ratio, the horizontal bearing capacity of model pile 1 is converted (for example, the similarity ratio N=50, the bearing capacity of the model pile is 10 kN, the bearing capacity of the prototype pile = 10×50^2 =25000 kN), that is, the horizontal bearing capacity of the offshore wind power prototype pile based on the rigid pile failure mode can be obtained.

Through the corresponding force reverse bending point position of model pile 1 under the action of horizontal force loads at all levels F ₁ ~ _F Changes in the position of the stress rebending point and the total pile side soil resistance p of the pile side soil.

It can be seen from the above that the detection test method of the present invention has the following beneficial effects:

1) Through the theoretical design simulation test of the rigid pile failure mode, the horizontal force load condition of the simulated pile under graded load is used to detect and predict the horizontal bearing capacity of the actual prototype pile foundation. Compared with the field test method, the cost is low and the influencing factors can be It can conveniently, accurately and systematically detect and predict the horizontal bearing capacity of pile foundations, avoiding the difficulty of on-site testing at sea. According to the large-diameter rigid pile design model, based on the total pile side soil resistance calculated through measured CPTU data and the measured pile shaft horizontal displacement, the accurate relationship between the total pile side soil resistance p-pile shaft horizontal displacement y _(z) can be obtained, and then Improve the prediction accuracy of the horizontal bearing capacity of large-diameter rigid piles for offshore wind power, and then combine it with relevant specifications to calculate the horizontal bearing capacity of offshore wind power piles.

2) Combining experimental test data with theoretical calculations, it is possible to determine the position of the pile foundation's stress inflection point, the resistance distribution of the pile side soil, and the pile foundation's ultimate bearing capacity, etc., and to fully evaluate the deformation and damage of the pile foundation under the action of horizontal force loads. process for research.

3) CPTU data has high accuracy and large quantity, which can directly reflect the properties of the soil and facilitate the detection and prediction of the horizontal bearing capacity of pile foundations.

To sum up, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (8)

1. A method for detecting and predicting the horizontal bearing capacity of offshore wind power piles, which is characterized by: including the following steps: S1. Set up the model box, and determine the size of the model pile (1) according to the similarity ratio of the model test under the prototype working conditions, including the diameter D of the model pile (1); S2. Set the pile installation position in the model box, set up a horizontal plastic deformation zone in front of the pile installation position, and set N measuring lines (2) passing through the center of the pile installation position in front of the pile installation position. On each measuring line ( 2) At least one measuring point (3) is set up on each of them. The measuring point (3) is located in the horizontal plastic deformation zone, and the distance H ₁ between the center of the measuring point (3) closest to the pile installation position and the center of the pile installation position is 1D. ~1.5D; S3. Fill the model box with test soil in accordance with the specified requirements; set up the CPTU measurement system and CPTU penetration system; S4. Install the model pile (1) at the pile installation position, insert the model pile (1) into the test soil, and have a deformation measuring mechanism on the model pile (1) for detecting the deformation of the pile body; S5. Estimate the ultimate horizontal bearing capacity F _max of the model pile (1). According to the size of F _max , set M level horizontal loads from small to large and record them as F ₁ ~ F _M respectively, N ≥ M, F _M ≥ _{F max} ; Using a graded loading method, forward horizontal force loads F ₁ ~F _M are sequentially applied to the model pile (1) in sequence. After each load is applied and stabilized, the CPTU probe (4) of the CPTU measurement system is used to measure a The CPTU test is performed at the measuring point (3) of line (2) until excessive pile displacement occurs when the horizontal force load F _X+1 is applied. If X ₊ 1≤M, the horizontal force load F For the actual _ultimate horizontal bearing capacity _of pile (1), the horizontal force _{load F} The disturbed CPTU measurement data is used to obtain the pile deformation of the model pile (1) under various levels of horizontal force loads F ₁ ~F _X through the deformation measurement mechanism; S6 _{. According} to the magnitude _{of the horizontal force load at each level from F 1 to} F ) The total pile side soil resistance p of the pile side soil and the horizontal displacement y _(z) of the model pile 1 at each depth z, combined with the total pile side soil resistance p and the horizontal displacement y _(z) , the model pile (1 ) py _(z) curve, thereby obtaining the py _(z) curve suitable for the rigid pile failure mode; the calculation method of the total pile side soil resistance p is: through the pile side soil resistance calculation formula established based on the hole expansion theory, first Calculate the pile side soil resistance p (z, y) at each depth z, , ,/> , ,/> , , where y is the horizontal displacement of the model pile (1) at the calculation point, converted by the pile deformation of the model pile (1); μ is the friction coefficient between the pile and soil; σ ₀ is the static earth pressure at the calculation point; C _u is Calculate the undrained shear strength of the soil at the calculation point; r ₀ is the radius of the model pile (1); K is the lateral soil stress coefficient at the calculation point; γ is the saturated weight of the soil around the pile; E is the deformation of the soil at the calculation point Modulus; ν is the Poisson's ratio of the soil at the calculation point; μ, C _u , K, E and ν are calculated from the CPTU measurement data of the measurement point (3) closest to the pile installation position, where Cu, K and E are calculated by The CPTU measurement data of measuring point (3) is calculated by referring to the corresponding recommended calculation formula in the "Technical Regulations for Bore Pressure Static Penetration Testing". μ is calculated based on the CPTU measurement data and the offshore wind power platform design specification "Offshore Fixed Platform Planning, Design and The recommended design parameters in the "Working Stress Design Method for Construction" recommend the selection of the tangent value of the pile-soil friction angle, and the Poisson's ratio ν is selected through the recommended value in the "Geotechnical Engineering Investigation Code"; through the pile side soil at each depth Resistance distribution, integrating along the depth can obtain the total pile side soil resistance suffered by the model pile (1)/> , z _max is the depth of penetration of model pile (1); S7. Based on the obtained py _(z) curve suitable for the failure mode of rigid piles and combined with relevant specifications, calculate the horizontal bearing capacity of offshore wind power piles. 2. The method for detecting and predicting the horizontal bearing capacity of offshore wind turbine piles according to claim 1, characterized in that: in step S1, the prototype working condition is the large-diameter steel pipe pile foundation of the offshore wind turbine, and the rigid pile is deformed and damaged. model. 3. The method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to claim 1, characterized in that in step S2, the horizontal plastic deformation zone is predetermined based on the rigid pile failure mode. 4. The method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to claim 1, characterized in that: in step S2, a straight line passing through the center of the pile installation position and along the front and rear directions is the horizontal load positioning line, and the adjacent measuring The angles between the lines (2) are equal, and the N measuring lines (2) are symmetrically distributed about the horizontal load positioning line. 5. The method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to claim 1, characterized in that in step S2, each measuring line (2) is 5.5D and 10.5D away from the center of the pile installation position (6). There are measuring points (3) respectively set at D. 6. The method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to claim 1, characterized in that: in the step S3, the test soil is prepared according to the geotechnical test method standard GB/T 50123-2019, and the filling soil is uniform and dense. and fully saturated. 7. The method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to claim 1, characterized in that: in the step S4, the deformation measurement mechanism includes strain gauges arranged on the front and rear sides of the model pile (1), Or it includes distributed optical fiber sensors arranged on the front and rear sides of the model pile (1). 8. The method for detecting and predicting the horizontal bearing capacity of offshore wind power piles according to claim 1, characterized in that step S6 further includes: calculating the model pile (1) according to the deformation amount of the pile body measured by the deformation measuring mechanism. The bending moment distribution of the pile body is determined, the reverse bending point of the model pile (1) is determined, and the deformation and failure mode of the model pile (1) is observed.