A method for calculating the sinking resistance of a suction cylinder

Abstract

The application relates to a suction cylinder sinking resistance calculation method and relates to the technical field of suction cylinder foundation construction, which comprises the following steps: calculating the clay content index of a clay-sand mixed soil layer by using a pore pressure static sounding test structure; calculating the upper limit value of the side resistance coefficient of the suction cylinder, the lower limit value of the side resistance coefficient of the suction cylinder, the upper limit value of the end resistance coefficient of the suction cylinder and the lower limit value of the end resistance coefficient of the suction cylinder according to the clay content index; and calculating the first sinking resistance based on the above resistance coefficients and by using a formula. The application establishes a suction cylinder sinking resistance calculation method for the clay-sand mixed soil layer, clearly defines the quantitative relationship between the clay content index of the clay-sand mixed soil layer and the sinking resistance coefficient (including the end resistance coefficient and the side resistance coefficient), solves the problem that the calculation parameters of the suction cylinder sinking resistance in the clay-sand mixed soil layer are not clear in the existing norms, and improves the accuracy of the sinking resistance calculation result.

Description

Technical Field

[0001] This application relates to the field of suction cylinder foundation construction technology, and in particular to a method for calculating the penetration resistance of a suction cylinder when it penetrates a clay-sand mixed soil layer. Background Technology

[0002] Currently, suction cylinder foundations have become a popular type of offshore wind turbine foundation. The sinking resistance is a prerequisite for determining the size of the suction cylinder foundation during the design phase and controlling the sinking negative pressure value during the sinking phase.

[0003] The calculation of the penetration resistance of suction cylinders often refers to the existing DNVGL-RP-C212 standard. However, the existing standard does not clearly specify the method for determining the penetration resistance coefficient of clay-sand mixed soil layers, which leads to a large uncertainty in the calculation results of the penetration resistance of suction cylinders in mixed soil layers.

[0004] Developing a method for calculating the penetration resistance of suction cylinders in clay-sand mixed soil layers is one of the important issues that needs to be addressed for the widespread application of suction cylinder foundations in offshore wind power. Summary of the Invention

[0005] This application provides a method for calculating the penetration resistance of suction cylinders in mixed soil layers. It can obtain the penetration resistance coefficient of clay-sand mixed soil layers based on the cone tip resistance and sidewall friction obtained by CPTu (piezocone penetration test), thereby improving the reliability of the penetration resistance calculation results.

[0006] On the one hand, a method for calculating the penetration resistance of a suction cylinder is provided, applicable to the calculation of penetration resistance when a suction cylinder penetrates in a clay-sand mixed soil layer; including:

[0007] Step S1: Obtain the cone tip resistance, sidewall friction resistance, and excess pore water pressure at different soil depths using static cone penetration tests. Calculate the clay content index based on these three parameters.

[0008] Step S2: Calculate the upper limit of the side resistance coefficient, the lower limit of the side resistance coefficient, the upper limit of the end resistance coefficient, and the lower limit of the end resistance coefficient of the suction cylinder based on the particle content index.

[0009] Step S3: Calculate the first penetration resistance of the suction cylinder based on the cone tip resistance, side resistance coefficient, and end resistance coefficient.

[0010] In some embodiments, in step S3, the first penetration resistance of the suction cylinder is calculated using the following formula:

[0011]

[0012] in,

[0013] R1 represents the first penetration resistance of the suction cylinder;

[0014] K p This represents the end resistance coefficient of the suction cylinder in the clay-sand mixture layer;

[0015] d represents the penetration depth of the suction cylinder in the clay-sand mixture layer;

[0016] A p This indicates the cross-sectional area of ​​the suction cylinder's end.

[0017] q c Indicates the resistance at the tip of the cone;

[0018] A s This represents the sum of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer;

[0019] K f This represents the lateral resistance coefficient of the suction cylinder in a clay-sand mixture layer;

[0020] S t This represents the sensitivity coefficient of the clay-sand mixture layer.

[0021] In some embodiments, the method further includes:

[0022] Step S4: Calculate the shear strength of the contact surface between the suction cylinder and the clay-sand mixture based on the sidewall friction.

[0023] Step S5: Calculate the second penetration resistance of the suction cylinder using the following formula:

[0024]

[0025] in,

[0026] R2 represents the second sinking resistance of the suction cylinder;

[0027] K p This represents the end resistance coefficient of the suction cylinder in the clay-sand mixture layer;

[0028] d represents the penetration depth of the suction cylinder in the clay-sand mixture layer;

[0029] A p This indicates the cross-sectional area of ​​the suction cylinder's end.

[0030] q c Indicates the resistance at the tip of the cone;

[0031] A s This represents the sum of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer;

[0032] τ represents the shear strength of the contact surface between the inner and outer walls of the suction cylinder and the clay-sand mixture layer;

[0033] S t This represents the sensitivity coefficient of the clay-sand mixture layer.

[0034] Step S6: Substitute the upper limit values ​​of the side resistance coefficient and the end resistance coefficient into the formula in step S3 to calculate the upper limit value of the first penetration resistance. Substitute the lower limit values ​​of the side resistance coefficient and the end resistance coefficient into the formula in step S3 to calculate the lower limit value of the first penetration resistance. Substitute both the upper limit value of the end resistance coefficient and the lower limit value of the end resistance coefficient into the formula in step S5 to calculate the second penetration resistance value. Determine whether the second penetration resistance value exceeds the range formed by the upper limit value of the first penetration resistance and the lower limit value of the first penetration resistance. If yes, the calculation result of step S3 is incorrect; if no, the calculation result of step S3 is correct.

[0035] In some embodiments, in step S4, the shear strength of the contact surface between the suction cylinder and the clay-sand mixture layer is calculated using the following formula:

[0036]

[0037] in,

[0038] τ represents the shear strength of the contact surface between the inner and outer walls of the suction cylinder and the clay-sand mixture layer;

[0039] f s This represents the frictional resistance of the sidewall.

[0040] In some embodiments, step S1 includes:

[0041] Step S11: Obtain the cone tip resistance, sidewall friction, and excess pore water pressure at different soil depths using a static cone penetration test.

[0042] Step S12: Calculate the cone tip resistance coefficient and friction ratio coefficient based on the cone tip resistance, sidewall friction resistance, and excess pore water pressure.

[0043] Step S13: Calculate the classification index of the clay-sand mixed soil layer based on the cone tip resistance coefficient and the friction ratio coefficient;

[0044] Step S14: Calculate the clay content index of the clay-sand mixed soil layer based on the classification index.

[0045] In some embodiments, in step S12, the cone tip resistance coefficient and friction ratio coefficient are calculated using the following formulas:

[0046]

[0047] in,

[0048] Q t Indicates the cone tip drag coefficient;

[0049] q c Indicates the resistance at the tip of the cone;

[0050] u represents excess pore water pressure;

[0051] 'a' represents the ratio of the upper and lower cross-sectional areas of the probe.

[0052] σ v0 This represents the self-weight stress corresponding to the soil depth.

[0053] This represents the effective self-weight stress corresponding to the calculated soil layer depth.

[0054] F r Indicates the friction ratio coefficient;

[0055] f s This represents the frictional resistance of the sidewall.

[0056] In some embodiments, in step S13, the classification index of the clay-sand mixed soil layer is calculated using the following formula:

[0057]

[0058] in,

[0059] I c The classification index represents the clay-sand mixed soil layer;

[0060] Q t Indicates the cone tip drag coefficient;

[0061] F r Indicates the friction ratio coefficient;

[0062] In step S14, the clay content index of the clay-sand mixed soil layer is calculated using the following formula:

[0063] FC = 1.31I c 3.76 -3.12 (%)

[0064] in,

[0065] FC represents the clay content index of clay-sand mixed soil layers;

[0066] I c This represents the classification index of clay-sand mixed soil layers.

[0067] In some embodiments, in step S2, the upper limit of the side resistance coefficient of the suction cylinder in the clay-sand mixture layer is calculated using the following formula:

[0068]

[0069] in,

[0070] K f.max This indicates the upper limit of the side resistance coefficient of the suction cylinder in the clay-sand mixture layer;

[0071] FC represents the clay content index of clay-sand mixed soil layers.

[0072] In some embodiments, in step S2, the lower limit of the side resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula:

[0073]

[0074] in,

[0075] K f.min This represents the lower limit of the side resistance coefficient of the suction cylinder in the clay-sand mixed soil layer;

[0076] FC represents the clay content index of clay-sand mixed soil layers.

[0077] In some embodiments, in step S2, the upper limit of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is 0.6;

[0078] In step S2, the lower limit of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula:

[0079]

[0080] in,

[0081] K p.min This represents the lower limit of the end resistance coefficient of the suction cylinder in the clay-sand mixture layer;

[0082] FC represents the clay content index of clay-sand mixed soil layers.

[0083] The beneficial effects of the technical solution provided in this application include:

[0084] This invention establishes a method for calculating the penetration resistance of suction cylinders in clay-sand mixed soil layers. It can obtain the penetration resistance coefficient of clay-sand mixed soil layers based on cone tip resistance and sidewall friction, and then calculate the penetration resistance based on the penetration resistance coefficient. It clarifies the quantitative relationship between the clay content index and the penetration resistance coefficient of clay-sand mixed soil layers, and solves the problem of unclear calculation parameters for suction cylinder penetration resistance in clay-sand mixed soil layers in the existing DNVGL-RP-C212 specification.

[0085] The first and second penetration resistances are calculated using the cone tip resistance and the side wall friction resistance. The value of the first penetration resistance is more affected by the cone tip resistance, while the value of the second penetration resistance is more affected by the side wall friction resistance. The first and second penetration resistances are cross-checked to improve the reliability of the first penetration resistance. Attached Figure Description

[0086] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0087] Figure 1 This is a flowchart of the method for calculating the penetration resistance of the suction cylinder in an embodiment of the present invention.

[0088] Figure 2 This is a flowchart of step S1 in an embodiment of the present invention.

[0089] Figure 3 The results of the static cone penetration test at the construction site of the suction cylinder in this embodiment of the invention are shown.

[0090] Figure 4 This is a comparison of the first and second penetration resistances with the measured values ​​in the embodiments of the present invention. Detailed Implementation

[0091] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0092] This application provides a method for calculating the penetration resistance of a suction cylinder, applicable to the calculation of penetration resistance when a suction cylinder penetrates a clay-sand mixed soil layer. The method includes calculating the clay content index of the clay-sand mixed soil layer using the test results of a pore pressure static cone penetration test, calculating the upper limit value, lower limit value, upper limit value, and lower limit value of the side resistance coefficient of the suction cylinder based on the clay content index, and calculating the first penetration resistance based on the above resistance coefficients and using a formula.

[0093] In this embodiment, the present invention establishes a method for calculating the penetration resistance of suction cylinders in clay-sand mixed soil layers, clarifies the quantitative relationship between the clay content index of clay-sand mixed soil layers and the penetration resistance coefficients (including end resistance coefficients and side resistance coefficients), and solves the problem of unclear calculation parameters for suction cylinder penetration resistance in clay-sand mixed soil layers in the existing DNVGL-RP-C212 specification.

[0094] Specifically, such as Figure 1 As shown, the calculation method for the penetration resistance of the suction cylinder includes:

[0095] Step S1: Obtain the cone tip resistance, sidewall friction, and excess pore water pressure at different soil depths using static cone penetration tests (CPTu). Calculate the clay content based on these three parameters. Specifically, different soil depths correspond to different cone tip resistance, sidewall friction, and excess pore water pressure. Collect CPTu test data at the suction cylinder construction site, with a set of data collected every 0.1–0.5 m below the seabed (riverbed) surface. The data includes the cone tip resistance, sidewall friction, and excess pore water pressure obtained from the static cone penetration tests.

[0096] Step S2: Calculate the upper limit, lower limit, upper limit, and lower limit of the side resistance coefficient, and the end resistance coefficient, based on the particle content index. Specifically, the upper limit, lower limit, upper limit, and lower limit of the side resistance coefficient can be calculated using formulas or set manually according to actual needs.

[0097] Step S3: Calculate the first penetration resistance of the suction cylinder using the following formula:

[0098]

[0099] Where R1 represents the first penetration resistance of the suction cylinder, K p A represents the end resistance coefficient of the suction cylinder in the clay-sand mixture layer, d represents the penetration depth of the suction cylinder in the clay-sand mixture layer, and A represents the penetration depth of the suction cylinder in the clay-sand mixture layer. p q represents the cross-sectional area of ​​the suction cylinder. c A represents the cone tip resistance. sK represents the sum of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer. f S represents the lateral resistance coefficient of the suction cylinder in a clay-sand mixture. t denoted by , where z represents the sensitivity coefficient of the clay-sand mixture layer, and z represents the coordinate axis along the depth direction of the clay-sand mixture layer.

[0100] Specifically, the penetration resistance of the suction cylinder is divided into two parts: end resistance and side resistance. The side resistance is the result of integrating the shear strength of the cylinder wall-foundation soil contact surface along the depth direction. This can simplify the calculation by dividing the cylinder wall into segments every 0.1 to 0.5 m along the depth direction. The side resistance coefficient in each segment can be represented by the calculated value at a certain depth. By accumulating the side resistance of each segment and the end resistance at the current depth, the penetration side resistance of the suction cylinder can be obtained.

[0101] This represents the cone tip resistance corresponding to the elevation of the bottom opening when the suction cylinder penetrates to a certain depth. This represents the sum of sidewall frictional forces within the depth range of 0 to d. This represents the sidewall friction resistance of the suction cylinder at different depths z.

[0102] Both the end resistance coefficient and the side resistance coefficient are calculated from the results of the pore pressure static cone penetration test, namely the cone tip resistance, sidewall friction, and excess pore water pressure. Since the formula in step S3 uses... As a coefficient, the value of the first penetration resistance is more affected by the cone tip resistance.

[0103] In a preferred embodiment, the method for calculating the penetration resistance of the suction cylinder further includes calculating a second penetration resistance using the cone tip resistance and the side wall friction resistance. The second penetration resistance is more affected by the side wall friction resistance. The first penetration resistance and the second penetration resistance are cross-checked to improve the reliability of the first penetration resistance.

[0104] Specifically, such as Figure 1 As shown, the method for calculating the penetration resistance of the suction cylinder further includes:

[0105] Step S4: Calculate the shear strength of the contact surface between the suction cylinder and the clay-sand mixture based on the sidewall friction resistance.

[0106] Step S5: Calculate the second penetration resistance of the suction cylinder using the following formula:

[0107]

[0108] Where R2 represents the second penetration resistance of the suction cylinder, K p A represents the end resistance coefficient of the suction cylinder in the clay-sand mixture layer, d represents the penetration depth of the suction cylinder in the clay-sand mixture layer, and A represents the penetration depth of the suction cylinder in the clay-sand mixture layer. pq represents the cross-sectional area of ​​the suction cylinder. c A represents the cone tip resistance. s S represents the sum of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer, τ represents the shear strength of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer, and S represents the shear strength of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer. t This represents the sensitivity coefficient of the clay-sand mixture layer.

[0109] Step S6: Substitute the upper limit values ​​of the side resistance coefficient and the end resistance coefficient into the formula in step S3 to calculate the upper limit value of the first penetration resistance. Substitute the lower limit values ​​of the side resistance coefficient and the end resistance coefficient into the formula in step S3 to calculate the lower limit value of the first penetration resistance. Substitute both the lower limit values ​​of the side resistance coefficient and the lower limit values ​​of the end resistance coefficient into the formula in step S5 to calculate the second penetration resistance value. Determine whether the second penetration resistance value exceeds the range formed by the upper limit value and the lower limit value of the first penetration resistance. If yes, the calculation result of step S3 is incorrect; if no, the calculation result of step S3 is correct.

[0110] Specifically, when the lower limit value R of the first penetration resistance is met... 1.min ≤Second penetration resistance R2≤Upper limit of first penetration resistance R 1.max If the result of the first sinking resistance calculated in step S3 is correct and reasonable, it can be used to guide the formulation of the suction cylinder sinking scheme; otherwise, the rationality of the algorithm should be checked.

[0111] In this embodiment, the end resistance coefficient and the side resistance coefficient are both calculated from the results of the pore pressure static penetration test, namely the cone tip resistance, the side wall friction resistance, and the excess pore water pressure. The shear strength is calculated from the side wall friction resistance. Since the formula in step S5 uses τ(z) as a coefficient, the value of the second penetration resistance is more affected by the side wall friction resistance.

[0112] The first and second penetration resistances are calculated using the cone tip resistance and the side wall friction resistance. The value of the first penetration resistance is more affected by the cone tip resistance, while the value of the second penetration resistance is more affected by the side wall friction resistance. The first and second penetration resistances are cross-checked to improve the reliability of the first penetration resistance.

[0113] In a preferred embodiment, in step S4, the shear strength of the contact surface between the suction cylinder and the clay-sand mixture layer is calculated using the following formula:

[0114]

[0115] Where τ represents the shear strength of the contact surface between the inner and outer walls of the suction cylinder and the clay-sand mixture layer, f s This represents the frictional resistance of the sidewall.

[0116] In this embodiment, the shear strength is calculated from the sidewall friction. In addition, τ(z) is used as a coefficient in the formula of step S5. Therefore, the second penetration resistance calculated in step S5 is more affected by the sidewall friction. That is, the second penetration resistance calculated in step S5 is mainly calculated from the sidewall friction. The second penetration resistance mainly calculated from the sidewall friction is compared with the first penetration resistance mainly calculated from the cone tip resistance to achieve mutual verification between the two, thereby improving the accuracy and reliability of the penetration resistance calculation results.

[0117] In a preferred embodiment, such as Figure 2 As shown, step S1 includes:

[0118] Step S11: Obtain the cone tip resistance, sidewall friction, and excess pore water pressure at different soil depths using a static cone penetration test.

[0119] Step S12: Calculate the cone tip resistance coefficient and friction ratio coefficient based on the cone tip resistance, sidewall friction resistance, and excess pore water pressure.

[0120] Step S13: Calculate the classification index of the clay-sand mixed soil layer based on the cone tip resistance coefficient and the friction ratio coefficient.

[0121] Step S14: Calculate the clay content index of the clay-sand mixed soil layer based on the classification index.

[0122] Furthermore, in step S12, the cone tip resistance coefficient and friction ratio coefficient are calculated using the following formulas:

[0123]

[0124] Among them, Q t q represents the cone tip drag coefficient. t =q c +u(1-a)(Formula 1), q c The cone tip resistance is represented by σ, u represents excess pore water pressure, a represents the ratio of the upper and lower cross-sectional areas of the probe, and σ represents the lower cross-sectional area of ​​the probe. v0 This indicates the calculation of the self-weight stress corresponding to the soil depth. F represents the effective self-weight stress corresponding to the calculated soil depth. r f represents the friction ratio coefficient. s This represents the frictional resistance of the sidewall.

[0125] In step S13, the classification index of the clay-sand mixed soil layer is calculated using the following formula:

[0126]

[0127] Among them, I cQ represents the classification index of clay-sand mixed soil layers. t F represents the cone tip drag coefficient. r This represents the friction ratio coefficient. Based on the classification index, soil layers are divided into three categories: clay, sand, and mixed soil. Soil layers with an index between 2.05 and 2.95 are classified as mixed soil, those less than 2.05 as sand, and those greater than 2.95 as clay.

[0128] In step S14, the clay content index of the clay-sand mixed soil layer is calculated using the following formula:

[0129] FC = 1.31I c 3.76 -3.12 (%) Equation 5

[0130] Wherein, FC represents the clay content index of the clay-sand mixed soil layer, and I c This represents the classification index of clay-sand mixed soil layers.

[0131] In this embodiment, the method of calculating the cone tip resistance coefficient and friction ratio coefficient based on the cone tip resistance, sidewall friction resistance, and excess pore water pressure is a well-known technical solution in the art. Other technical solutions can also be used to obtain the cone tip resistance, sidewall friction resistance, and excess pore water pressure and calculate the cone tip resistance coefficient and friction ratio coefficient.

[0132] In a preferred embodiment, in step S2, the upper limit of the side resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula:

[0133]

[0134] Among them, K f.max FC represents the upper limit of the lateral resistance coefficient of the suction cylinder in the clay-sand mixed soil layer, and FC represents the clay content index of the clay-sand mixed soil layer.

[0135] In step S2, the lower limit of the side resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula:

[0136]

[0137] Among them, K f.min FC represents the lower limit of the lateral resistance coefficient of the suction cylinder in the clay-sand mixed soil layer, and FC represents the clay content index of the clay-sand mixed soil layer.

[0138] In step S2, the upper limit value K of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is... p.max =0.6 (Equation 9).

[0139] In step S2, the lower limit of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula:

[0140]

[0141] Among them, K p.min FC represents the lower limit of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer, and FC represents the clay content index of the clay-sand mixed soil layer.

[0142] In this embodiment, the coefficients in the formula for calculating the drag coefficient are derived from a preset value.

[0143] In one specific embodiment, the suction cylinder penetration resistance calculation method is applied to the suction cylinder penetration resistance and negative pressure assessment of a wind power project. The suction cylinder has an outer diameter of 13.5m, a height of 19.0m, and a wall thickness of 32.0mm. The site consists of layers of silt, silty clay, and clay-silty clay from top to bottom. The CPTu test results within the site area are as follows: Figure 3 As shown. Taking 11.50~12.00m as an example, the penetration resistance is calculated.

[0144] Statistical analysis of CPTu test results, q c =1.576MPa, f s =31.49kPa, u=540.57kPa, the area ratio of the static contact probe is 0.86, and q is calculated. t =q c +u(1-a)=1.652MPa. The normalized cone tip resistance and sidewall friction were calculated using the methods described in Equations 2 and 3, yielding Qt=17.82 and Fr=2.17.

[0145] The soil classification index I is calculated using the method described in Equation 4. c =2.71, and the classification index is between 2.05 and 2.95, indicating that the soil layer is a clay-sand mixture.

[0146] The clay content FC of the mixed soil layer was calculated as 41.0 (%) using the method described in Formula 5.

[0147] The methods described in Equations 6 to 9 are used to calculate the upper and lower limit coefficients of the penetration resistance and end resistance:

[0148]

[0149]

[0150]

[0151] K p.max =0.6.

[0152] As shown in Equation 10, the side resistance and end resistance of the suction cylinder within the depth range of 11.5 to 12.0 m are calculated respectively, and the upper limit value of the end resistance R is obtained. 1b.max =1283.23kN, lower limit of end resistance R 1b.min =733.58kN, the soil sensitivity coefficient is 1.68, and the upper limit of the lateral resistance is R. 1f.max = 888.55kN, the lower limit of the side resistance is R 1f.min =514.32kN.

[0153] The method shown in Equation 11 calculates based on f s The shear strength at the suction cylinder-foundation soil interface was calculated, yielding a shear strength τ = 23.53 kPa.

[0154] The penetration resistance R is calculated using the method shown in Equation 12. 2f =997.94.

[0155] Calculate the penetration resistance and end resistance at other depths based on the steps described above.

[0156] Based on q c and f s The penetration resistance of the suction cylinder was calculated, and the penetration negative pressure value of the suction cylinder was obtained by converting the top cover area and structural self-weight. The comparison results with the measured values ​​are as follows: Figure 4 As shown.

[0157] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0158] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0159] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for calculating the penetration resistance of a suction cylinder, applicable to the calculation of penetration resistance when a suction cylinder penetrates in a clay-sand mixed soil layer; characterized in that, include: Step S1: Obtain the cone tip resistance, sidewall friction resistance, and excess pore water pressure at different soil depths using static cone penetration tests. Calculate the clay content index based on these three parameters. Step S2: Calculate the upper limit of the side resistance coefficient, the lower limit of the side resistance coefficient, the upper limit of the end resistance coefficient, and the lower limit of the end resistance coefficient of the suction cylinder based on the particle content index. Step S3: Calculate the first penetration resistance of the suction cylinder based on the cone tip resistance, side resistance coefficient, and end resistance coefficient; Step S4: Calculate the shear strength of the contact surface between the suction cylinder and the clay-sand mixture based on the sidewall friction. Step S5: Calculate the second penetration resistance of the suction cylinder using the following formula: in, This represents the second penetration resistance of the suction cylinder; This represents the end resistance coefficient of the suction cylinder in the clay-sand mixture layer; d represents the penetration depth of the suction cylinder in the clay-sand mixture layer; This indicates the cross-sectional area of ​​the suction cylinder's end. Indicates the resistance at the tip of the cone; This represents the sum of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer; This indicates the shear strength of the contact surface between the inner and outer walls of the suction cylinder and the clay-sand mixture layer; This represents the sensitivity coefficient of the clay-sand mixture layer; Step S6: Substitute the upper limit values ​​of the side resistance coefficient and the end resistance coefficient into the formula in step S3 to calculate the upper limit value of the first penetration resistance. Substitute the lower limit values ​​of the side resistance coefficient and the end resistance coefficient into the formula in step S3 to calculate the lower limit value of the first penetration resistance. Substitute both the upper limit value of the end resistance coefficient and the lower limit value of the end resistance coefficient into the formula in step S5 to calculate the second penetration resistance value. Determine whether the second penetration resistance value exceeds the range formed by the upper limit value of the first penetration resistance and the lower limit value of the first penetration resistance. If yes, the calculation result of step S3 is incorrect; if no, the calculation result of step S3 is correct.

2. The method for calculating the penetration resistance of a suction cylinder as described in claim 1, characterized in that, In step S3, the first penetration resistance of the suction cylinder is calculated using the following formula: in, This indicates the first penetration resistance of the suction cylinder; This represents the end resistance coefficient of the suction cylinder in the clay-sand mixture layer; d represents the penetration depth of the suction cylinder in the clay-sand mixture layer; This indicates the cross-sectional area of ​​the suction cylinder's end. Indicates the resistance at the tip of the cone; This represents the sum of the contact areas between the inner and outer walls of the suction cylinder and the clay-sand mixture layer; This represents the lateral resistance coefficient of the suction cylinder in a clay-sand mixture layer; This represents the sensitivity coefficient of the clay-sand mixture layer.

3. The method for calculating the penetration resistance of a suction cylinder as described in claim 1, characterized in that, In step S4, the shear strength of the contact surface between the suction cylinder and the clay-sand mixture layer is calculated using the following formula: in, This indicates the shear strength of the contact surface between the inner and outer walls of the suction cylinder and the clay-sand mixture layer; This represents the frictional resistance of the sidewall.

4. The method for calculating the penetration resistance of a suction cylinder as described in claim 1, characterized in that, Step S1 includes: Step S11: Obtain the cone tip resistance, sidewall friction, and excess pore water pressure at different soil depths using a static cone penetration test. Step S12: Calculate the cone tip resistance coefficient and friction ratio coefficient based on the cone tip resistance, sidewall friction resistance, and excess pore water pressure. Step S13: Calculate the classification index of the clay-sand mixed soil layer based on the cone tip resistance coefficient and the friction ratio coefficient; Step S14: Calculate the clay content index of the clay-sand mixed soil layer based on the classification index.

5. The method for calculating the penetration resistance of a suction cylinder as described in claim 4, characterized in that, In step S12, the cone tip resistance coefficient and friction ratio coefficient are calculated using the following formulas: in, Indicates the cone tip drag coefficient; Indicates the resistance at the tip of the cone; u represents excess pore water pressure; 'a' represents the ratio of the upper and lower cross-sectional areas of the probe. This represents the self-weight stress corresponding to the soil depth. This represents the effective self-weight stress corresponding to the calculated soil layer depth. Indicates the friction ratio coefficient; This represents the frictional resistance of the sidewall.

6. The method for calculating the penetration resistance of a suction cylinder as described in claim 4, characterized in that, In step S13, the classification index of the clay-sand mixed soil layer is calculated using the following formula: in, The classification index represents the clay-sand mixed soil layer; Indicates the cone tip drag coefficient; Indicates the friction ratio coefficient; In step S14, the clay content index of the clay-sand mixed soil layer is calculated using the following formula: in, This indicates the clay content index of the clay-sand mixed soil layer; This represents the classification index of clay-sand mixed soil layers.

7. The method for calculating the penetration resistance of a suction cylinder as described in claim 1, characterized in that, In step S2, the upper limit of the side resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula: in, This indicates the upper limit of the side resistance coefficient of the suction cylinder in the clay-sand mixture layer; FC represents the clay content index of clay-sand mixed soil layers.

8. The method for calculating the penetration resistance of a suction cylinder as described in claim 1, characterized in that, In step S2, the lower limit of the side resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula: in, This represents the lower limit of the side resistance coefficient of the suction cylinder in the clay-sand mixture layer; FC represents the clay content index of clay-sand mixed soil layers.

9. The method for calculating the penetration resistance of a suction cylinder as described in claim 1, characterized in that, In step S2, the upper limit of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is 0.6; In step S2, the lower limit of the end resistance coefficient of the suction cylinder in the clay-sand mixed soil layer is calculated using the following formula: in, This represents the lower limit of the end resistance coefficient of the suction cylinder in the clay-sand mixture layer; FC represents the clay content index of clay-sand mixed soil layers.

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