CN116695800B - Detection and prediction method for horizontal bearing capacity of offshore wind power pile - Google Patents
Detection and prediction method for horizontal bearing capacity of offshore wind power pile Download PDFInfo
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- E—FIXED CONSTRUCTIONS
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- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
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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
Technical Field
The invention relates to the field of geotechnical engineering, in particular to a detection and prediction method for horizontal bearing capacity of an offshore wind power pile.
Background
Under the development trend of developing and utilizing green energy, offshore wind power is taken as a clean energy source, has the irreplaceable advantages of high energy benefit, small occupied land resources and the like, and is rapidly developed worldwide. The offshore wind turbine often adopts a large-diameter rigid pile foundation, and compared with a land pile foundation, the offshore wind pile foundation bears larger wind and wave load in the horizontal direction, and the horizontal bearing capacity is a key factor affecting the safety of the offshore wind pile foundation.
At present, common methods for evaluating the horizontal bearing capacity of the offshore wind power pile foundation comprise a theoretical method based on foundation parameters, a design method, a field horizontal pile pushing load test and the like. The theoretical method adopts a hole expansion theory to estimate the pile surrounding soil resistance distribution so as to calculate the horizontal bearing capacity of the pile body, but because calculation parameters such as the non-drainage shear strength, the poisson ratio, the modulus and the like of the soil body in a pile surrounding plastic region required in the hole expansion theory are difficult to directly obtain, most of the calculation parameters are determined by an empirical formula, so that the reliability of theoretical calculation results is lower; the design method is mainly based on a horizontal bearing capacity-displacement curve (namely a p-y curve) formed by fitting the small-diameter flexible pile pushing experimental results recommended in the API specification to calculate the bearing capacity, but the offshore wind power pile is a rigid pile, the p-y curve is inconsistent with a rigid pile damage mode, and the design calculation result is inaccurate. The on-site horizontal pile pushing load test of the offshore wind power pile foundation is limited by equipment and cost, the adopted test pile has larger phase difference with an actual pile foundation, the cost is high, and the pile pushing load test is more difficult to use particularly when the pile is of a large diameter.
Static cone penetration test (cone penetration test, CPT) is an important in-situ test technology in the field of geotechnical engineering, and is mainly used for soil layer division, field liquefaction discrimination, foundation soil layer physical mechanical parameter estimation, foundation bearing capacity assessment, pile foundation bearing capacity estimation and the like at present. The pore-pressure static cone penetration test (piezocone penetration test, CPTU) has become an important reference basis for engineering design parameters of the offshore wind power pile foundation, has the advantages of intuitiveness, rapidness, data continuity and the like, can directly obtain indexes such as cone tip resistance, side wall friction resistance and the like of soil layers around the pile foundation on site, and intuitively reflects physical and mechanical properties of soil around the pile.
In the prior art, due to the limitation of loading equipment in a complex offshore environment, the in-situ test of the horizontal bearing capacity test for the offshore wind power pile foundation site is often difficult, the acquired data are difficult to analyze due to excessive influence factors, and the horizontal bearing capacity performance of the offshore wind power pile foundation is difficult to accurately obtain
Disclosure of Invention
In view of the shortcomings of the prior art, the technical problem to be solved by the invention is to provide a method for detecting and predicting the horizontal bearing capacity of an offshore wind power pile, and the horizontal bearing capacity condition of a rigid pile foundation can be conveniently, accurately and systematically estimated by adopting a model test mode.
In order to achieve the above purpose, the invention provides a method for detecting and predicting the horizontal bearing capacity of an offshore wind power pile, which comprises the following steps:
s1, setting a model box, and determining the size of the model pile according to the similarity ratio of a model test designed by the prototype working condition, wherein the size comprises the diameter D of the model pile.
S2, arranging a pile installation position in the model box, arranging a horizontal plastic deformation zone in front of the pile installation position, arranging N measuring lines passing through the center of the pile installation position in front of the pile installation position, arranging at least one measuring point on each measuring line, wherein the measuring point is positioned in the horizontal plastic deformation zone, and the distance H between the center of the measuring point closest to the pile installation position and the center of the pile installation position 1 1D to 1.5D.
S3, filling test soil into the model box according to the specified requirement; setting a CPTU measurement system and a CPTU penetration system.
And S4, installing a model pile at the pile installation position, inserting the model pile into the test soil, and arranging a deformation measuring mechanism for detecting the deformation of the pile body on the model pile.
S5, estimating the ultimate horizontal bearing capacity F of the model pile max According to F max Setting M-level horizontal loads from small to large and respectively denoted as F 1 ~F M ，N≥M，F M ≥F max The method comprises the steps of carrying out a first treatment on the surface of the Sequentially applying forward horizontal force loads F to the model piles in sequence by adopting a staged loading mode 1 ~F M After each load application and stabilization, CPTU testing is performed at the measurement point of one line using the CPTU probe of the CPTU measurement system until a horizontal force load F is applied X+1 When the pile displacement is overlarge, X+1 is less than or equal to M, the horizontal force load F X+1 The actual limit horizontal bearing capacity of the model pile is exceeded, and the horizontal force is loaded F X The actual measurement limit horizontal bearing capacity of the model pile is marked as F Actual measurement The method comprises the steps of carrying out a first treatment on the surface of the Obtaining each horizontal force load F 1 ~F X CPTU measurement data after disturbance of soil for lower test, and obtain horizontal force load F of each stage through deformation measuring mechanism 1 ~F X Pile body deformation of the model pile below.
S6, according to F 1 ~F X Each level of horizontal force load and corresponding CPTU measurement data and deformation of the model pile to obtain F 1 ~F X Under the action of horizontal force loads of all levels, the total pile side soil resistance p of the corresponding model pile side soil and the horizontal displacement y of the model pile at each depth z （z） Combining the total pile side soil resistance p and the horizontal displacement y （z） Fitting to obtain p-y of model pile （z） Curve to obtain p-y suitable for rigid pile failure mode （z） A curve.
S7, according to the obtained p-y suitable for the rigid pile failure mode （z） And (3) calculating the horizontal bearing capacity of the offshore wind turbine pile by combining the curves with the related specifications.
Further, in the step S1, the prototype working condition is a large-diameter steel pipe pile foundation of the offshore wind turbine, and is a rigid pile deformation failure mode.
Further, in the step S2, the horizontal plastic deformation zone is predicted according to the rigid pile-based failure mode.
Further, in step S2, the straight line passing through the center of the pile installation position and along the front-rear direction is a horizontal load positioning line, the included angles between adjacent measuring lines are equal, and the N measuring lines are symmetrically distributed about the horizontal load positioning line.
Further, in the step S2, each measuring line is provided with a measuring point at a distance of 5.5D and 10.5D from the pile-mounting position center, respectively.
Further, in the step S3, test soil is prepared according to the geotechnical test method standard GB/T50123-2019, and the filled soil is uniform and compact and fully saturated.
Further, in the step S4, the deformation measuring mechanism includes strain gauges disposed on the front and rear sides of the model pile, or includes distributed optical fiber sensors disposed on the front and rear sides of the model pile.
Further, the step S6 further includes: and calculating pile body bending moment distribution conditions of the model pile according to the pile body deformation measured by the deformation measuring mechanism, judging the reverse bending point of the model pile, and observing the deformation damage mode of the model pile.
Further, in the step S6, the total pile side soil resistance p is calculated by: pile side soil resistance p (z, y) at each depth z is calculated and obtained through a pile side soil resistance calculation formula established based on a cavity expansion theory,，，，，，wherein y is the horizontal displacement of the model pile at the calculation point, and the deformation of the pile body of the model pile is converted; mu is the friction coefficient between piles and soil;σ 0 the static soil pressure of the point is calculated; c (C) u The non-drainage shear strength of the point soil body is calculated; r is (r) 0 Is the radius of the model pile; k is the lateral soil stress coefficient of the calculated point; gamma is the saturation severity of soil around the pile; e is the deformation modulus of the calculated point soil body; v is the poisson ratio of the soil mass of the calculation point; mu, C u K, E and v are calculated from CPTU measurement data of the measurement point closest to the pile installation site; the total pile side soil resistance of the model pile can be obtained along the depth integral according to the pile side soil resistance distribution condition at each depth,z max Is the depth of the model pile.
Further, the step S6 further includes: and detecting and predicting the horizontal bearing capacity of the offshore wind turbine pile based on the rigid pile failure mode through the comparison analysis of the total pile side soil resistance calculation result and the actual measurement limit horizontal bearing capacity of the model pile.
As described above, the detection and prediction method according to the present invention has the following advantages:
1) The horizontal bearing capacity condition of the actual prototype pile foundation is detected and predicted by using the horizontal bearing capacity condition of the simulation pile under the classified load through the rigid pile failure mode theoretical design simulation test, compared with the mode of the field test, the method has the advantages of low cost and controllable influence factors, can conveniently, accurately and systematically detect and predict the horizontal bearing capacity of the pile foundation, and avoids the difficulty of the field test at sea. According to the design model of the large-diameter rigid pile, based on the total pile side soil resistance calculated by actually measured CPTU data and the actual measured horizontal displacement of the pile body, the accurate total pile side soil resistance p and the accurate horizontal displacement y of the pile body can be obtained （z） The relation of (a), i.e. p-y （z） And the curve is used for further improving the prediction precision of the horizontal bearing capacity of the offshore wind power large-diameter rigid pile, and then combining with related specifications, so that the horizontal bearing capacity of the offshore wind power pile can be calculated.
2) The test data are combined with theoretical calculation, so that the positions of stressed reverse bending points of the pile foundations, the resistance distribution of soil at the pile sides, the ultimate bearing capacity of the pile foundations and the like can be judged, and the whole deformation and damage process of the pile foundations under the action of horizontal force load can be studied.
3) CPTU data accuracy is high, and is large in quantity, the property of soil can be directly reflected, and the horizontal bearing capacity of the pile foundation can be conveniently detected and predicted.
Drawings
FIG. 1 is a flow chart of a method for detecting and predicting the horizontal bearing capacity of an offshore wind pile.
FIG. 2 is a schematic diagram of the measuring lines and measuring points in the present invention.
Fig. 3 is a schematic diagram of the present invention when measuring at a measuring point of a certain measuring line.
Detailed Description
Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present invention, which is described by the following specific examples.
It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the invention, are included in the spirit and scope of the invention which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper", "lower", "left", "right", "middle", etc. are used herein for convenience of description, but are not to be construed as limiting the scope of the invention, and the relative changes or modifications are not to be construed as essential to the scope of the invention.
Referring to fig. 1 to 3, the invention provides a method for detecting and predicting horizontal bearing capacity of an offshore wind power pile, which comprises the following steps:
s1, setting a model box, and determining the size of the model pile 1 according to the similarity ratio of a model test designed by a prototype working condition, wherein the size comprises the diameter D of the model pile 1. The large-diameter steel pipe pile foundation of the offshore wind turbine, which presents a rigid pile deformation and damage mode, is used as a prototype working condition, and the model pile 1 is a rigid pile. The size of the model box can be selected to be proper according to practical situations.
S2, arranging a pile mounting position for mounting a model pile 1 in a model box, arranging a horizontal plastic deformation zone in front of the pile mounting position, arranging N measuring lines 2 passing through the center of the pile mounting position in front of the pile mounting position, wherein the measuring lines 2 pass through the horizontal plastic deformation zone, each measuring line 2 is provided with at least one measuring point 3, the measuring points 3 are positioned in the horizontal plastic deformation zone, and the measuring point 3 closest to the pile mounting position is closest to the model pile 1 at the position of the pile mounting position as far as possible, and the distance H between the center of the model pile and the center of the pile mounting position 1 Meets 1D to 1.5D. The pile mounting position is located at a proper position of the model box, preferably at a middle position in the left-right direction of the model box. The horizontal plastic deformation region is a region where the model pile 1 installed at the pile installation site is subjected to forward horizontal force loading force F, and the pile side soil is plastically deformed.
In this embodiment, the horizontal plastic deformation zone is a sector zone with its center located at the center of the pile installation site, that is, on the central axis of the installed model pile 1, which is predicted based on the rigid pile failure mode and the size of the model pile 1. Of course, the horizontal plastic deformation zone may also be determined using any suitable method known in the art.
Referring to fig. 2, in the present embodiment, preferably, the number n=5 of the measuring lines 2, the included angles between the adjacent measuring lines 2 are equal, the straight line passing through the center of the pile installation position and along the front-rear direction is a horizontal load positioning line, and the horizontal plastic deformation area is symmetrical about the horizontal load positioning line. Preferably, 5 lines 2 are symmetrically distributed about the horizontal load positioning line, that is, one line 2 coincides with the horizontal load positioning line, the line 2 is denoted as L5, two sides of the horizontal load positioning line are respectively provided with two measurements, the two outermost lines 2 are respectively denoted as L1 and L2, the included angle between the two lines 2, namely L1 and L2, is 120 ° near two radial edges of the sector-shaped horizontal plastic deformation region, the L3 line 2 is between the two lines 2, namely L1 and L5, the L4 line 2 is between the two lines 2, namely L2 and L5, and the included angle between the adjacent lines 2 is 30 °.
Referring to FIG. 2, preferably, in the present embodiment, three measurement points are provided on each of the measurement lines 23, corresponding to any one of the measuring lines 2 with the number Li, wherein three measuring points 3 are respectively marked as P i-1 、P i-2 And P i-3 ， P i-1 The measuring point 3 is closest to the center of the pile installation position, P i-1 、P i-2 And P i-3 The distance distribution between the centers of the three measuring points 3 and the center of the pile installation position is H 1 、H 2 And H 3 ， H 1 1.5D, H 2 And H 3 5.5D and 10.5D, respectively.
S3, filling test soil in a model box according to the specified requirement, specifically, preparing the test soil according to the geotechnical test method standard GB/T50123-2019, uniformly compacting the filled soil, and fully saturating the filled soil to ensure that the test soil can simulate the soil foundation of an actual offshore wind turbine pile. The CPTU measuring system and the CPTU penetrating system are arranged, wherein the CPTU measuring system is provided with a CPTU probe 4, and preferably, the CPTU measuring system further comprises a positioning mechanism, the CPTU probe 4 can be driven to move above each measuring point 3 under the control of a computer through the positioning mechanism, and the CPTU penetrating system can penetrate the CPTU probe 4 downwards into filling test soil. Both the CPTU measurement system and the CPTU penetration system may employ existing configurations.
Preferably, in this step, the CPTU probe 4 of the CPTU measurement system is penetrated into the soil for test and measured by the CPTU penetration system, so as to obtain the CPTU reference parameter of the soil for test when the pile foundation disturbance is not passed, wherein the CPTU reference parameter comprises three indexes of cone tip resistance, sidewall friction resistance and pore water pressure, and the variation curve of each index along with the penetration depth can be obtained in the penetration measurement process of the CPTU probe 4. The measurement of the CPTU reference parameter may be performed before driving the model pile 1, or may be performed after driving the model pile 1, and the measured position is required to satisfy a distance requirement, and the distance between the position and the center of the pile installation position is required to be greater than 10.5D, which is not affected by the driving of the model pile 1. And (3) measuring at a position far away from the pile installation position, penetrating the CPTU probe 4 to a certain depth through a CPTU penetrating system, and completing one-time measurement, wherein measured data acquired by the CPTU probe 4 are recorded as CPTU reference parameters.
And S4, installing a model pile 1 at a pile installation position, inserting the model pile 1 into test soil, and arranging a deformation measuring mechanism for detecting the deformation of the pile body on the model pile 1. The deformation measuring mechanism can adopt strain gages, the strain gages are arranged on the front side and the rear side of the model pile 1, and the deformation of the pile body is determined through the strain gages on the two sides. The deformation measuring mechanism can also adopt distributed optical fiber sensors, the distributed optical fiber sensors are arranged on the front side and the rear side of the model pile 1, and the deformation of the pile body is determined through the distributed optical fiber sensors on the two sides.
S5, estimating the ultimate horizontal bearing capacity F of the model pile max According to F max Setting M-level horizontal loads from small to large and respectively denoted as F 1 ~F M ，N≥M，F M ≥F max Wherein the interval difference of the horizontal force loads of two adjacent stages can be calculated according to F max Setting the size and the condition of the model pile 1; the model piles 1 are sequentially applied with forward horizontal force loads F by adopting a staged loading mode 1 ~F M Horizontal force load is applied to the proper position of the model pile 1 above the surface of the soil for test, and after each load application and stabilization, CPTU test is performed at the measurement point 3 of one test line 2 by using a CPTU measurement system and a CPTU penetration system (the load is kept during the test until the X+1st level horizontal load F is applied) X+1 When the pile displacement is overlarge, X+1 is less than or equal to M, the pile displacement is that the horizontal displacement of the model pile 1 on the soil surface under the horizontal force load exceeds the maximum value of the design requirement, and the specification of the technical specification of water transport engineering foundation experiment detection (JTS 237-2017) can be referred to, and the horizontal load F is described at the moment X+1 When the actual limit horizontal bearing capacity of the model pile 1 is exceeded, loading the X-th level horizontal force F X The actual measurement limit horizontal bearing capacity of the model pile is marked as F Actual measurement ，F Actual measurement =F X . Simultaneously obtaining each horizontal force load F 1 ~F X CPTU measurement data after disturbance of soil for lower test, and obtain horizontal force load F of each stage through deformation measuring mechanism 1 ~F M Pile body deformation amount of the model pile 1 below.
In the present embodiment, in particular, upon application of any horizontal force load F i When i is not less than 1 and not more than X, the Li is selected on the Li measuring line 2P i-1 、P i-2 And P i-3 The three measuring points 3 are used for measuring, the CPTU probe 4 penetrates into the test soil at the measuring points 3 to obtain CPTU measurement data, the CPTU measurement data comprise three indexes of cone tip resistance, side wall friction resistance and pore water pressure, and in the penetrating measurement process of the CPTU probe 4, the change curve of each index along with the penetrating depth can be obtained. In the penetration measurement process, when the data measured by the CPTU probe 4 is not changed or has a small change but the change condition is within a specified range, the lower soil layer is not changed, namely the plastic deformation depth of the pile side soil is exceeded, and the penetration of the CPTU probe 4 is stopped. Preferably, the data measured by the CPTU probe 4 may also be compared with the CPTU reference parameters in step S3 to determine the condition of the soil layer, to determine the plastic deformation depth therein, and to determine whether to stop the penetration. CPTU probe 4 at P i-1 The penetration depth at the measuring point 3 is at least about 70% of the penetration depth of the model pile 1. Finally obtain the load F to horizontal force i Corresponding CPTU measurement data and obtaining a horizontal force load F through a deformation measurement mechanism i Corresponding pile body deformation.
S6, according to F 1 ~F X The level force load of each level, CPTU measurement data corresponding to the level force load and the deformation of the model pile 1 are obtained to obtain F 1 ~F X Under the action of horizontal force loads of all levels, the total pile side soil resistance p of the corresponding pile side soil of the model pile 1 and the horizontal displacement y of the model pile 1 at each depth z （z） Combining the total pile side soil resistance p and the horizontal displacement y （z） Fitting the p-y of the model pile 1 （z） Curve to obtain p-y suitable for rigid pile failure mode （z） A curve. Meanwhile, the stress buckling point positions of the model piles 1 under the action of horizontal force loads of all levels can be obtained.
In this step, specifically, the manner of obtaining the stress buckling point position is: and according to the pile body deformation measured by the deformation measuring mechanism, calculating the pile body bending moment distribution condition of the model pile 1, judging the reverse bending point of the model pile 1, and observing the deformation damage mode of the model pile 1.
In this step, by hole-based expansionA pile side soil resistance calculation formula established by the tension theory is used for calculating and obtaining pile side soil resistance p (z, y) at each depth z,，，，，，wherein y is the horizontal displacement of the model pile 1 at the depth z of the soil, and μ is the coefficient of friction between the piles, σ, calculated by the deformation of the pile body of the model pile 1 0 To calculate the stationary earth pressure of the point C u To calculate the non-drainage shear strength of the point soil mass, r 0 Is the radius of the model pile 1; k is the lateral soil stress coefficient of the calculated point, gamma is the saturation weight of the soil body around the pile, E is the deformation modulus of the soil body of the calculated point, and v is the Poisson's ratio of the soil body of the calculated point. The relevant parameters of the test soil, namely mu, cu, K, E and v, are according to P nearest to the pile installation position i-1 CPTU measurement data for measurement Point 3 and associated specifications, in particular Cu, K and E are determined by P i-1 CPTU measurement data of the measurement point 3 are calculated by referring to a corresponding recommended calculation formula in Cone cone penetration test technical Specification (TCCES 1-2017). μ is selected according to CPTU measurement data and tangent values of pile-soil friction angles recommended by Table 6.4.3-1 design parameters in the working stress design method of recommended practice for offshore fixed platform planning, design and construction (SY/T10030-2018) of the offshore wind platform design Specification. Poisson's ratio v can be selected by the recommended value of 10.2.5 part in geotechnical engineering investigation Specification (GB 50021-2001, 2009). R is R p2 For the radius of the sector of horizontal plastic deformation zone actually produced in the body after horizontal displacement of the pile, the measurement points 3 can be variedCPTU measurement data estimation. By the pile side soil resistance calculation formula established based on the hole expansion theory, the pile side soil resistance distribution condition of the model pile 1 at each depth under the action of horizontal force load can be obtained, and the total pile side soil resistance of the model pile 1 can be obtained along the depth integral，z max Is the penetration depth of the model pile 1. The total pile side soil resistance of the model pile 1 is the theoretical calculated value of the horizontal bearing capacity of the model pile 1. And, by horizontal force loading F X (i.e. measured ultimate horizontal bearing capacity F of model pile 1) Actual measurement ) Calculation result of total pile side soil resistance p and actual measurement limit horizontal bearing capacity F of model pile 1 Actual measurement And (3) performing comparative analysis to verify whether the obtained theoretical calculation value of the horizontal bearing capacity (total pile side soil resistance p) is reasonable.
S7, according to the obtained p-y suitable for the rigid pile failure mode （z） And (3) calculating the horizontal bearing capacity of the offshore wind turbine pile by combining the curves with the related specifications. In particular, when it is desired to predict the horizontal bearing capacity of a certain offshore wind power pile, p-y according to the resulting rigid pile failure mode （z） Curves, each depth corresponding to a p-y （z） And (3) combining the method in related specifications such as an API RP 2A WSD or a recommended method working stress design method (SY/T10030-2018) for planning, designing and constructing an offshore fixed platform, taking the maximum horizontal displacement of the pile at the soil surface as an initial condition, and carrying out iterative calculation to obtain the total lateral soil resistance of the rigid pile when the maximum horizontal displacement is reached at the soil surface, wherein the total lateral soil resistance is the horizontal bearing capacity of the offshore wind power pile.
And converting the horizontal bearing capacity of the model pile 1 according to the model test similarity ratio (such as similarity ratio N=50, model pile bearing capacity of 10 kN, prototype pile bearing capacity=10×50≡2=25000 kN) through the horizontal bearing capacity theoretical calculation value of the model pile 1, namely, obtaining the horizontal bearing capacity condition of the offshore wind power prototype pile based on the rigid pile failure mode.
Through F 1 ~F X Horizontal force loading at each levelThe stress reverse bending point position of the corresponding model pile 1 and the total pile side soil resistance p of the pile side soil under the action can also obtain the change condition of the stress reverse bending point position and the total pile side soil resistance p of the pile side soil when the horizontal force load gradually increases to the maximum bearing capacity.
From the above, the detection test method of the invention has the following beneficial effects:
1) The horizontal bearing capacity condition of the actual prototype pile foundation is detected and predicted by using the horizontal force load condition of the simulation pile under the classified load through the theoretical design simulation test of the rigid pile failure mode, compared with the mode of the field test, the method has the advantages of low cost and controllable influence factors, can conveniently, accurately and systematically detect and predict the horizontal bearing capacity of the pile foundation, and avoids the difficulty of the field test at sea. According to the design model of the large-diameter rigid pile, based on the total pile side soil resistance calculated by actually measured CPTU data and the actually measured pile body horizontal displacement, the accurate total pile side soil resistance p-pile body horizontal displacement y can be obtained （z） The prediction precision of the horizontal bearing capacity of the offshore wind power large-diameter rigid pile is further improved, and the horizontal bearing capacity of the offshore wind power pile can be calculated by combining the related specifications.
2) The test data are combined with theoretical calculation, so that the positions of stressed reverse bending points of the pile foundations, the resistance distribution of soil at the pile sides, the ultimate bearing capacity of the pile foundations and the like can be judged, and the whole deformation and damage process of the pile foundations under the action of horizontal force load can be studied.
3) CPTU data accuracy is high, and is large in quantity, the property of soil can be directly reflected, and the horizontal bearing capacity of the pile foundation can be conveniently detected and predicted.
In summary, the present invention effectively overcomes the disadvantages of the prior art and has high industrial utility value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (8)
1. A detection and prediction method for the horizontal bearing capacity of an offshore wind power pile is characterized by comprising the following steps of: the method comprises the following steps:
s1, setting a model box, and determining the size of a model pile (1) according to the similarity ratio of a model test designed by a prototype working condition, wherein the size comprises the diameter D of the model pile (1);
s2, setting a pile installation position in a model box, setting a horizontal plastic deformation zone in front of the pile installation position, setting N measuring lines (2) passing through the center of the pile installation position in front of the pile installation position, and setting at least one measuring point (3) on each measuring line (2), wherein the measuring point (3) is positioned in the horizontal plastic deformation zone, and the distance H between the center of the measuring point (3) closest to the pile installation position and the center of the pile installation position 1 1D to 1.5D;
s3, filling test soil into the model box according to the specified requirement; setting a CPTU measurement system and a CPTU penetration system;
s4, installing a model pile (1) at a pile installation position, inserting the model pile (1) into test soil, and arranging a deformation measuring mechanism for detecting the deformation of the pile body on the model pile (1);
s5, estimating the ultimate horizontal bearing capacity F of the model pile (1) max According to F max Setting M-level horizontal loads from small to large and respectively denoted as F 1 ~F M ，N≥M，F M ≥F max The method comprises the steps of carrying out a first treatment on the surface of the The model piles (1) are sequentially applied with forward horizontal force loads F by adopting a staged loading mode 1 ~F M After each application and stabilization of the load, CPTU testing is performed at the measurement point (3) of one of the lines (2) using the CPTU probe (4) of the CPTU measurement system until a horizontal force load F is applied X+1 When the pile displacement is overlarge, X+1 is less than or equal to M, the horizontal force load F X+1 Has exceeded the practical limit horizontal bearing capacity of the model pile (1), and loads the horizontal force F X The actual measurement limit horizontal bearing capacity of the model pile (1) is marked as F Actual measurement The method comprises the steps of carrying out a first treatment on the surface of the Obtaining each horizontal force load F 1 ~F X CPTU measurement data after disturbance of soil for lower test, and obtain horizontal force load F of each stage through deformation measuring mechanism 1 ~F X Pile body deformation of the model pile (1) below;
s6, according to F 1 ~F X The level force load of each level, CPTU measurement data corresponding to the level force load and deformation of the model pile (1) are obtained to obtain F 1 ~F X The total pile side soil resistance p of the corresponding model pile (1) pile side soil under the action of horizontal force load of each level and the horizontal displacement y of the model pile 1 at each depth z （z） Combining the total pile side soil resistance p and the horizontal displacement y （z） Fitting to obtain p-y of the model pile (1) （z） Curve to obtain p-y suitable for rigid pile failure mode （z） A curve; the calculation method of the total pile side soil resistance p comprises the following steps: pile side soil resistance p (z, y) at each depth z is calculated and obtained through a pile side soil resistance calculation formula established based on a cavity expansion theory,，，/>，，/>，wherein y is the horizontal displacement of the model pile (1) of the calculation point, and the deformation of the pile body of the model pile (1) is converted; mu is the friction coefficient between piles and soil; sigma (sigma) 0 The static soil pressure of the point is calculated; c (C) u The non-drainage shear strength of the point soil body is calculated; r is (r) 0 Is the radius of the model pile (1); k is the lateral soil stress coefficient of the calculated point; gamma is soil mass around pileSaturation severity; e is the deformation modulus of the calculated point soil body; v is the poisson ratio of the soil mass of the calculation point; mu, C u The method comprises the steps that K, E and v are calculated by CPTU measurement data of a measurement point (3) closest to a pile installation position, cu, K and E are calculated by the CPTU measurement data of the measurement point (3) according to a corresponding recommended calculation formula in a "hole-pressure static cone penetration test technical rule", mu is selected according to CPTU measurement data and a tangent value of a pile-soil friction angle recommended by design parameters in a "working stress design method of offshore fixed platform planning, design and construction recommended practice" of offshore wind power platform design rule, and Poisson ratio v is selected by a recommended value in a "geotechnical engineering investigation rule"; by the pile side soil resistance distribution at each depth, the total pile side soil resistance suffered by the model pile (1) can be obtained along the depth integral>,z max The depth of the model pile (1) into the soil;
s7, according to the obtained p-y suitable for the rigid pile failure mode （z） And (3) calculating the horizontal bearing capacity of the offshore wind turbine pile by combining the curves with the related specifications.
2. The method for detecting and predicting the horizontal bearing capacity of the offshore wind power pile according to claim 1, wherein the method comprises the following steps: in the step S1, the prototype working condition is a large-diameter steel pipe pile foundation of the offshore wind turbine and is a rigid pile deformation and damage mode.
3. The method for detecting and predicting the horizontal bearing capacity of the offshore wind power pile according to claim 1, wherein the method comprises the following steps: in the step S2, the horizontal plastic deformation zone is predicted according to the rigid pile-based failure mode.
4. The method for detecting and predicting the horizontal bearing capacity of the offshore wind power pile according to claim 1, wherein the method comprises the following steps: in the step S2, the straight line passing through the center of the pile installation position and along the front-rear direction is a horizontal load positioning line, the included angles between the adjacent measuring 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 the offshore wind power pile according to claim 1, wherein the method comprises the following steps: in the step S2, each measuring line (2) is respectively provided with a measuring point (3) at positions 5.5D and 10.5D from the center of the pile installation position (6).
6. The method for detecting and predicting the horizontal bearing capacity of the offshore wind power pile according to claim 1, wherein the method comprises the following steps: in the step S3, test soil is prepared according to the geotechnical test method standard GB/T50123-2019, and the filled soil is uniform and compact and fully saturated.
7. The method for detecting and predicting the horizontal bearing capacity of the offshore wind power pile according to claim 1, wherein the method comprises the following steps: in the step S4, the deformation measuring mechanism includes strain gauges disposed on front and rear sides of the model pile (1), or includes distributed optical fiber sensors disposed on front and rear sides of the model pile (1).
8. The method for detecting and predicting the horizontal bearing capacity of the offshore wind power pile according to claim 1, wherein the method comprises the following steps: the step S6 further includes: and calculating pile body bending moment distribution conditions of the model pile (1) according to the pile body deformation measured by the deformation measuring mechanism, judging a reverse bending point of the model pile (1), and observing a deformation damage mode of the model pile (1).
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105002938A (en) * | 2015-07-29 | 2015-10-28 | 浙江大学 | One-dimensional horizontal circulation load loading device and experiment method thereof |
| CN106442937A (en) * | 2016-10-14 | 2017-02-22 | 中交天津港湾工程研究院有限公司 | Novel marine shallow soil feature detection system and evaluation method thereof |
| CN109930635A (en) * | 2019-03-29 | 2019-06-25 | 中国电建集团华东勘测设计研究院有限公司 | The model system and test method of single-pile foundation in a kind of silt soil strata |
| CN110029692A (en) * | 2019-04-24 | 2019-07-19 | 上海应用技术大学 | The method for determining bearing capacity of single pile timeliness in weak soil based on SCPTu probe test value |
| CN114218653A (en) * | 2021-12-20 | 2022-03-22 | 中铁大桥局集团第五工程有限公司 | Method for calculating bearing capacity of suction pile foundation of offshore construction platform |
| CN115559361A (en) * | 2022-09-28 | 2023-01-03 | 东南大学 | Indoor pile foundation model test device and method for multiple horizontal cyclic loading working conditions |
| CN115573397A (en) * | 2022-09-23 | 2023-01-06 | 上海勘测设计研究院有限公司 | Evaluation model design and evaluation method for soil compaction effect of offshore wind power pile foundation soil plug |
-
2023
- 2023-08-01 CN CN202310956016.9A patent/CN116695800B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105002938A (en) * | 2015-07-29 | 2015-10-28 | 浙江大学 | One-dimensional horizontal circulation load loading device and experiment method thereof |
| CN106442937A (en) * | 2016-10-14 | 2017-02-22 | 中交天津港湾工程研究院有限公司 | Novel marine shallow soil feature detection system and evaluation method thereof |
| CN109930635A (en) * | 2019-03-29 | 2019-06-25 | 中国电建集团华东勘测设计研究院有限公司 | The model system and test method of single-pile foundation in a kind of silt soil strata |
| CN110029692A (en) * | 2019-04-24 | 2019-07-19 | 上海应用技术大学 | The method for determining bearing capacity of single pile timeliness in weak soil based on SCPTu probe test value |
| CN114218653A (en) * | 2021-12-20 | 2022-03-22 | 中铁大桥局集团第五工程有限公司 | Method for calculating bearing capacity of suction pile foundation of offshore construction platform |
| CN115573397A (en) * | 2022-09-23 | 2023-01-06 | 上海勘测设计研究院有限公司 | Evaluation model design and evaluation method for soil compaction effect of offshore wind power pile foundation soil plug |
| CN115559361A (en) * | 2022-09-28 | 2023-01-03 | 东南大学 | Indoor pile foundation model test device and method for multiple horizontal cyclic loading working conditions |
Non-Patent Citations (3)
| Title |
|---|
| 基于CPTU 测试太湖软土地层单桩水平承载实用分析及案例研究;李洪江等;岩土工程学报;第40卷(第2期);第378-383页 * |
| 基于CPTU测试p-y曲线法及其在桩基水平承载中的应用;李洪江;刘松玉;童立元;;岩石力学与工程学报(第02期);全文 * |
| 基于CPTU测试的桩基承载力预测新方法;蔡国军;刘松玉;;岩土工程学报(第S2期);全文 * |
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