A method for predicting lateral deformation of foundation with vacuum combined preloading and drainage board

Abstract

The present invention discloses a method for predicting the lateral deformation of a drainage board foundation under vacuum combined preloading, comprising the steps of calculating the initial undrained shear strength of the foundation soil, calculating dimensionless characteristic parameters, calculating the stress ratio of the soil at the end of the preloading, calculating the reference vertical strain of the soil under one-dimensional compression conditions, calculating the ratio of the lateral strain to the one-dimensional compressive strain of the soil, calculating the lateral strain of the soil, and calculating the lateral deformation of the foundation. This application is based on a relationship diagram between the stress ratio and the characteristic parameters and a quantitative relationship diagram between the lateral strain / one-dimensional compressive strain of the soil and the soil stress ratio / static earth pressure coefficient of the soil. The method can quickly calculate the lateral deformation of the drainage board foundation under vacuum combined preloading, providing a reference for the design of drainage board foundations treated with vacuum combined preloading.

Description

Technical Field

[0001] The invention belongs to the technical field of soft soil foundation treatment, and in particular relates to a method for predicting the lateral deformation of a vacuum combined loading preloading drainage board foundation. Background Art

[0002] In engineering projects, vertically inserted plastic drainage boards (hereinafter referred to as drainage boards) are often used in combination with a preloading method (also known as drainage consolidation method) to reinforce soft soil foundations. The preloading forms of the drainage consolidation method include surcharge preloading, vacuum preloading, and vacuum combined surcharge preloading. Due to the poor engineering properties of soft soil foundations, large deformations (including settlement and lateral displacement) often occur under the action of preloading loads. Existing studies have shown that excessive lateral deformation will have adverse effects on surrounding underground facilities or structures (such as pile foundations, bridge piers, abutments, and underground pipelines, etc.). In severe cases, it may even lead to damage to the structure and endanger the safety and stability of underground facilities. Therefore, it is particularly important to systematically evaluate the impact of drainage board foundation deformation on surrounding buildings and the environment during the design and construction stages. One of the key points is how to accurately analyze and predict the lateral deformation of the drainage board foundation under preloading loads. However, the current prediction methods for the lateral deformation of drainage board foundations under vacuum combined preloading are not in-depth and comprehensive enough. There is a lack of an analysis method that directly considers the main influencing factors (such as the size of the load, the size of the vacuum pressure, and the initial stress state of the foundation soil) and has a direct and convenient calculation process. As a result, it is difficult for engineers to quickly and accurately quantitatively analyze the lateral deformation of drainage board foundations under combined preloading.

[0003] In summary, it is necessary to propose a method that comprehensively considers all the main influencing factors and can directly obtain the lateral deformation of the vacuum combined surcharge preloading drainage foundation. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for predicting the lateral deformation of the foundation of a vacuum combined preloaded drainage board. e The relationship between the characteristic parameters β and ε h / ε v1 (ε h is the lateral strain, ε v1 is the reference vertical strain under one-dimensional compression of soil) and K e / K0 (K0 is the static earth pressure coefficient of soil) is the main body, which can quickly calculate the lateral deformation of the drainage board foundation under vacuum combined surcharge preloading, and provide a reference for the relevant design of the drainage board foundation under vacuum combined surcharge preloading treatment.

[0005] To this end, the present invention provides a method for predicting lateral deformation of a vacuum combined preloaded drainage board foundation, comprising the following steps:

[0006] S1. Calculate the initial undrained shear strength s of the foundation soilu0

[0007] S2. Calculate dimensionless characteristic parameter β

[0008] According to the pile load p s , vacuum pressure p v , heap loading rate LR, initial vacuum pressure consolidation time t v , load application time t s , initial undrained shear strength of foundation soil s u0 The relevant parameters of the consolidation and drainage of the drainage board foundation are calculated by the following formula to obtain the characteristic parameter β:

[0009]

[0010]

[0011] Where c h is the horizontal consolidation coefficient of soil, r s is the radius of the drainage board coating area, r w is the equivalent radius of the drainage board, r e is the equivalent radius of the drainage board unit, q w is the drainage volume per unit time of the drainage board, k h is the horizontal permeability coefficient of the undisturbed soil, k s is the permeability coefficient of the soil in the smear area, l is the length of the drain plate, and μ is a dimensionless parameter related to the consolidation analysis of the drain plate foundation.

[0012] S3, according to the characteristic parameter β calculated in step S2, refer to K e -β relationship diagram, the stress ratio K of the soil at the end of the loading is calculated according to the following formula e :

[0013]

[0014] S4. Calculate the reference vertical strain ε under one-dimensional compression of soil v1 , as follows:

[0015]

[0016] Among them, e0 is the initial porosity of the soil, C c is the compression index, σ′ vo is the initial vertical effective stress of soil;

[0017] S5. Calculate the ratio K based on the known static earth pressure coefficient K0 e / K0, and refer to ε h / ε v1 -K e / K0 quantitative relationship diagram, ε is calculated according to the following formula h / ε v1 :

[0018] f(x)=0.25[-0.23+7.66e (-x / 0.19) ]+0.75[-0.159+11.04e (-x / 0.15) +1.03e (-x / 0.50) ](11)

[0019] Among them, ε h is the lateral strain of the soil, f(x) represents ε h / ε v1 The value of x represents the ratio K e / K0;

[0020] S6. Vertical strain ε under one-dimensional compression condition calculated according to step S4 v1 and ε calculated in step S5 h / ε v1 Calculate the lateral strain ε of the soil under triaxial test conditions h ;

[0021] S7, according to ε h The lateral deformation of the foundation is calculated according to the following formula:

[0022] δ=0.5Bε h (12).

[0023] Specifically, according to the initial effective stress conditions and soil parameters of the foundation soil, the initial undrained shear strength s of the foundation soil is calculated according to formulas (1)-(4): u0 ;

[0024]

[0025]

[0026] q=σ′ v0 -σ′ h0 (3)

[0027]

[0028] Where p' and q are the average effective stress and deviatoric stress of the soil, respectively; M is the slope of the critical stress state line of the soil, OCR is the overconsolidation ratio of the soil, and σ' is ... vo is the initial vertical effective stress of the soil, σ′ ho is the initial horizontal effective stress of the soil, C c is the compression index, C s is the expansion index, Λ is the c and Cs The relevant dimensionless parameters.

[0029] Specifically, for plane strain conditions, the lateral strain under triaxial conditions needs to be converted into the lateral strain under plane strain conditions. Based on elastic theory, the lateral strain under plane strain conditions can be converted from the lateral strain under triaxial conditions using the following formula:

[0030]

[0031] Where, ε hp is the lateral strain of soil under plane strain conditions, ε h is the lateral strain of soil under triaxial test conditions, and ν is the Poisson's ratio of soil.

[0032] Specifically, when calculating the dimensionless characteristic parameter β, the pile load p s is the maximum additional stress on the soil at each depth in the center of the preloading area under the maximum design load, which is calculated according to the calculation method of additional stress on the foundation in soil mechanics. v is the actual vacuum pressure of the soil at each depth in the center of the preloading area, and the initial vacuum pressure consolidation time t v The time from the start of vacuum pressure application to the start of load application, load application time t s It is the time from the beginning of the application of the load to the time it reaches the maximum design value.

[0033] Specifically, ε h / ε v1 -K e The quantitative relationship diagram of / K0 includes ε with and without prior vacuum consolidation time. h / ε v1 ~K e / K0, f(x) represents the relationship curve of ε under the combined preloading condition when the vacuum consolidation time is included and the vacuum consolidation time is not included. h / ε v1 and K e / K0 unified relationship:

[0034] f(x)=a·f1(x)+b·f2(x) (14)

[0035] f1(x)=-0.23+7.66e (-x / 0.19) (15)

[0036] f2(x)=-0.159+11.04e (-x / 0.15) +1.03e (-x / 0.50) (16)

[0037] Where f(x) represents ε under the unified relationshiph / ε v1 The value of f1(x) represents the ε under the condition of prior vacuum consolidation time. h / ε v1 value, f2(x) represents the ε under the condition of no prior vacuum consolidation time h / ε v1 Value, x represents the ratio K e / K0, a and b are constants, and the values of a and b are 0.25 and 0.75 respectively.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention comprehensively considers the influence of drainage parameters, installation parameters, soil parameters and preload conditions of the drainage board, and takes the soil stress ratio K e The relationship between the characteristic parameters β and ε h / ε v1 With K e The quantitative relationship diagram of / K0 is the main body, and the relationship diagram is relatively simple, avoiding the more complicated analysis process in the existing graphic method. The method of the present invention can be more simple and quick;

[0040] In addition, relevant empirical relationships are given to make up for the shortcomings of poor value accuracy in existing graphical methods and improve the calculation accuracy of lateral deformation. According to the known drainage parameters, installation parameters, soil parameters and preloading load conditions of the drain board, the lateral deformation profile of the foundation soil along the depth direction after the preloading is completed can be calculated, which can provide an effective reference for the relevant reinforcement treatment design of soft soil foundations. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 The soil stress ratio K involved in this invention e Relationship diagram with characteristic parameter β;

[0043] Figure 2 This invention relates to ε h / ε v1 With K e / K0 quantitative relationship diagram;

[0044] Figure 3 It is a schematic diagram of the specific cross-section and soil parameters of the roadbed project involved in the engineering case of the present invention. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] The method for predicting lateral deformation of drainage board foundation under vacuum combined heap loading preloading provided by the present invention comprises the following steps:

[0047] S1, according to the initial effective stress condition of foundation soil (σ' h0 and σ' v0 ) and soil parameters (C c 、C s and M), calculate the initial undrained shear strength s of the foundation soil according to formulas (1) to (4): u0 Of course, if there is a measured value, the s obtained from the on-site in-situ test can also be used directly. u0 value.

[0048]

[0049]

[0050] q=σ′ v0 -σ′ h0 (3)

[0051]

[0052] Where p' and q are the average effective stress and deviatoric stress of the soil, respectively; M is the slope of the critical stress state line of the soil, OCR is the overconsolidation ratio of the soil, and σ' is ... vo is the initial vertical effective stress of the soil, σ′ ho is the initial horizontal effective stress of the soil, C c is the compression index, C s is the expansion index, Λ is the c and C s The relevant dimensionless parameters.

[0053] S2. Calculate the dimensionless characteristic parameter β;

[0054] According to the pile load p s , vacuum pressure p v , heap loading rate LR, initial vacuum pressure consolidation time t v , load application time t s , initial undrained shear strength of foundation soil s u0and the relevant parameters of drainage board foundation consolidation and drainage (i.e. r e 、r w ,、r s 、c h and k h / k s ), the characteristic parameter β is calculated by the following formula:

[0055]

[0056]

[0057] Where c h is the horizontal consolidation coefficient of soil, r s is the radius of the drainage board coating area, r w is the equivalent radius of the drainage board, r e is the equivalent radius of the drainage board unit, q w is the drainage volume per unit time of the drainage board, k h is the horizontal permeability coefficient of the undisturbed soil, k s is the permeability coefficient of the soil in the smear area, l is the length of the drain plate, and μ is a dimensionless parameter related to the consolidation analysis of the drain plate foundation.

[0058] S3, see Figure 1 , the characteristic parameter β calculated according to S2, according to K e -β relationship diagram, the stress ratio K of the soil at the end of the loading is calculated according to the following formula e :

[0059]

[0060] In addition, according to the method of the present invention, the soil stress ratio K e The 95% confidence limit (K et ) and the lower limit (K eb ) are:

[0061]

[0062]

[0063] S4. Calculate the reference vertical strain ε under one-dimensional compression of soil v1 , as follows:

[0064]

[0065] Where e0 is the initial porosity of the soil.

[0066] S5, see Figure 2 , calculate the ratio K based on the known static earth pressure coefficient K0e / K0, and through ε h / ε v1 -K e / K0 quantitative relationship diagram, ε is calculated according to the following formula h / ε v1 :

[0067] f(x)=0.25[-0.23+7.66e (-x / 0.19) ]+0.75[-0.159+11.04e (-x / 0.15) +1.03e (-x / 0.50) ](11)

[0068] Where f(x) represents ε h / ε v1 The value of x represents the ratio K e / K0.

[0069] S6. Reference vertical strain ε under one-dimensional compression conditions calculated according to step S4 v1 and ε calculated by S5 h / ε v1 value, calculate the lateral strain ε of the soil h ;

[0070] S8, according to ε h The lateral deformation of the PVD foundation is calculated based on the value and the width B of the vacuum combined preloading zone:

[0071] δ=0.5Bε h (12)

[0072] When applying the above method to solve engineering problems similar to plane strain conditions such as embankments, the lateral strain under triaxial conditions must be converted to the lateral strain under plane strain conditions. Based on elastic theory, the lateral strain under plane strain conditions can be converted from the lateral strain under triaxial conditions using the following formula:

[0073]

[0074] Where, ε hp is the lateral strain increment of soil under plane strain conditions, ε h is the lateral strain increment of soil under triaxial test conditions, and ν is the Poisson's ratio of soil.

[0075] Specifically, when calculating the dimensionless parameter β, the load p s is the maximum additional stress on the soil at each depth in the center of the preloading area under the maximum design load, which can be calculated according to the calculation method of additional stress on the foundation in soil mechanics. v is the actual vacuum pressure of the soil at each depth in the center of the preloading area, and the initial vacuum pressure consolidation time tv The time from the start of vacuum pressure application to the start of load application, load application time t s It is the time from the beginning of the application of the load to the time it reaches the maximum design value.

[0076] Understandably, see Figure 1 , in K e In the -β relationship diagram, K e -β relationship data points are a banded area with a regional confidence of 95%. The K e The -β relationship is the empirical relationship for the center line of the strip area. Figure 1 Soil stress ratio K e The center line of the relationship with the characteristic parameter β is the regression curve, and the dotted lines on both sides of the center line are the upper and lower limit curves of 95% confidence level.

[0077] See also Figure 2 , in ε h / ε v1 -K e / K0 quantitative relationship diagram includes the initial vacuum consolidation time (i.e. t v ≠0) and no prior vacuum consolidation time (ie t v =0) h / ε v1 ~K e / K0, the present invention uses f(x) to represent the comprehensive consideration of the initial vacuum consolidation time (i.e., t v ≠0) and no prior vacuum consolidation time (ie t v =0), in the case of combined preloading, ε h / ε v1 and K e / K0 unified relationship:

[0078] f(x)=a·f1(x)+b·f2(x) (14)

[0079] f1(x)=-0.23+7.66e (-x / 0.19) (15)

[0080] f2(x)=-0.159+11.04e (-x / 0.15) +1.03e (-x / 0.50) (16)

[0081] Where f(x) represents ε under the unified relationship h / ε v1 The value of f1(x) represents the ε under the condition of the initial vacuum consolidation time. h / ε v1 value, f2(x) represents the ε under the condition of no prior vacuum consolidation time h / εv1 Value, x represents the ratio K e / K0, a and b are constants. The present invention recommends that the values of a and b be 0.25 and 0.75 respectively.

[0082] Figure 2 Medium h / ε v1 With K e The / K0 data point is obtained based on the multi-condition finite element simulation analysis of the drainage plate foundation soil unit under vacuum combined with surcharge preloading, and can be divided into two curves according to whether there is a prior vacuum consolidation time. In the finite element analysis, the vacuum pressure is applied instantaneously to the design value. However, in actual engineering practice, for the case without prior vacuum consolidation time (i.e., t v =0), the vacuum pressure under the sealing geomembrane needs to go through a period of time to reach the designed vacuum degree, and then the load is applied on the sealing membrane. In fact, there is a certain prior vacuum consolidation time, and there is no joint preloading situation without prior vacuum consolidation time in the strict sense.

[0083] In addition, for the actual engineering, the initial vacuum consolidation time (ie t v ≠0), since the vacuum pressure takes some time to reach the design value, the initial vacuum consolidation time of the soil under the design vacuum degree is actually shorter than the initial vacuum consolidation time t set in the numerical simulation analysis. v Therefore, for specific engineering practice, ε h / ε v1 With K e The actual relationship curve of / K0 should be located at Figure 2 The f1(x) curve and the f2(x) curve obtained by finite element simulation analysis are between . Therefore, in order to make the method of the present invention more applicable to engineering practice, the present invention comprehensively considers the initial vacuum consolidation time (i.e., t v ≠0) and no prior vacuum consolidation time (ie t v =0) under the condition of combined preloading h / ε v1 -K e / K0 relationship curve, and proposed a unified ε under combined preloading conditions h / ε v1 and K e / K0 quantitative relationship (i.e., formula (14)).

[0084] In order to verify the reliability of the method of the present invention, the method of the present invention was applied to the lateral deformation calculation in a number of actual engineering cases, and the initial vacuum consolidation time (i.e., t v ≠0) and no prior vacuum consolidation time (ie t v=0), plane strain problem and triaxial stress-strain problem, and comprehensively considered common engineering practices. Verification and analysis showed that the predicted values of lateral deformation were in good agreement with the measured values, the predicted lateral deformation trend was basically consistent with the curve, and the measured lateral curve was generally within the predicted lateral deformation range, which verified the effectiveness and applicability of the method.

[0085] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0086] (1) Comprehensive consideration of the initial vacuum consolidation time (i.e., t v ≠0) and no prior vacuum consolidation time (ie t v =0) are closer to the specific situation in actual engineering.

[0087] (2) The relationship diagram provided is more concise, avoiding the more complicated analysis process in the existing graphical method. The method of the present invention can be used more simply and quickly; and the relevant empirical relationship formula is provided, which makes up for the shortcoming of poor value accuracy in the existing graphical method and improves the calculation accuracy.

[0088] (3) The method of the present invention can provide a lateral deformation prediction interval with a confidence level of 95%, which is convenient for effectively evaluating the impact of lateral deformation during the design stage of preloading reinforcement projects.

[0089] In summary, this analysis method can provide an effective reference for related designs.

[0090] The following is a brief description of one of the engineering cases: This project is a roadbed project. The upper and lower widths of the trapezoidal roadbed cross section are 22.4m and 30m respectively, and the height is 2.54m. The specific cross-section and soil parameters are shown in Figure 3 , where γ t and γ em are the weights of foundation soil and roadbed fill, c v The vertical consolidation coefficient of the soil. The length of the plastic drainage board is 20m, and it is set in a square with a spacing of 1m. Its drainage parameters are: drainage capacity q w 0.274m 3 / day,r w 、r s and r e The horizontal consolidation coefficient c of the soil is 0.025m, 0.1m and 0.565m respectively. h is the vertical consolidation coefficient c v 3 times, k h / k sThe ratio is 3.0. The on-site engineering data shows that the vacuum preloading was carried out for 55 days before the loading, and the vacuum pressure under the membrane was 80kPa. According to the on-site excess pore water pressure monitoring results, considering that the vacuum degree decreases linearly with the increase of depth, the vacuum pressure decreases linearly from 80kPa at the surface to 30kPa at a depth of 20m. It took 78 days to fill the roadbed to the design height, during which the vacuum pressure remained unchanged. Figure 1 Soil stress ratio K e The calculated values of lateral deformation at depths of 5m and 8.5m obtained from the centerline analysis of the relationship with the characteristic parameter β are -0.103m and -0.093m, respectively (the negative sign indicates that the lateral deformation is toward the inside of the roadbed). The errors with the measured values of -0.100m and -0.098m are 3% and 5%, respectively, indicating that the calculated values are in good agreement with the measured values.

[0091] The above embodiments are merely examples to clearly illustrate the present invention and are not intended to limit its implementation. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to provide an exhaustive list of all embodiments. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for predicting lateral deformation of a vacuum combined preloaded drainage board foundation, characterized in that: The steps include: S1. Calculate the initial undrained shear strength s of the foundation soil u0 ; S2, calculate the dimensionless characteristic parameter β; According to the pile load p s , vacuum pressure p v , heap loading rate LR, initial vacuum pressure consolidation time t v , load application time t s , initial undrained shear strength of foundation soil s u0 The relevant parameters of the consolidation and drainage of the drainage board foundation are calculated by the following formula to obtain the characteristic parameter β: Where c h is the horizontal consolidation coefficient of soil, r s is the radius of the drainage board coating area, r w is the equivalent radius of the drainage board, r e is the equivalent radius of the drainage board unit, q w is the drainage volume per unit time of the drainage board, k h is the horizontal permeability coefficient of the undisturbed soil, k s is the permeability coefficient of the soil in the smear area, l is the length of the drain plate, and μ is a dimensionless parameter related to the consolidation analysis of the drain plate foundation; S3, according to the characteristic parameter β calculated in step S2, refer to K e -β relationship diagram, the stress ratio K of the soil at the end of the loading is calculated according to the following formula e : S4. Calculate the reference vertical strain ε under one-dimensional compression of soil v1 , as follows: Among them, e0 is the initial porosity of the soil, C c is the compression index, σ′ v0 is the initial vertical effective stress of soil; S5. Calculate the ratio K based on the known static earth pressure coefficient K0 e / K0, and refer to ε h / ε v1 -K e / K0 quantitative relationship diagram, ε is calculated according to the following formula h / ε v1 : f(x)=0.25[-0.23+7.66e (-x / 0.19) ]+0.75[-0.159+11.04e (-x / 0.15) +1.03e (-x / 0.50) ](11) Among them, ε h is the lateral strain of the soil, f(x) represents ε h / ε v1 The value of x represents the ratio K e / K0; S6. Vertical strain ε under one-dimensional compression condition calculated according to step S4 v1 and ε calculated in step S5 h / ε v1 Calculate the lateral strain ε of the soil under triaxial test conditions h ; S7, according to ε h The lateral deformation of the foundation is calculated according to the following formula: δ=0.5Vε h (12)。 2. The method for predicting lateral deformation of a foundation of a vacuum combined preloaded drainage board according to claim 1 is characterized by: According to the initial effective stress conditions and soil parameters of the foundation soil, the initial undrained shear strength s of the foundation soil is calculated according to formulas (1)-(4): u0 ; q=σ′ v0 -s′ h0 (3) Where p' and q are the average effective stress and deviatoric stress of the soil, respectively; M is the slope of the critical stress state line of the soil, OCR is the overconsolidation ratio of the soil, and σ' is ... v0 is the initial vertical effective stress of the soil, σ′ h0 is the initial horizontal effective stress of the soil, C c is the compression index, C s is the expansion index, Λ is the c and C s The relevant dimensionless parameters.

3. The method for predicting lateral deformation of a foundation with vacuum combined preloading and drainage board according to claim 1 is characterized by: Initial undrained shear strength of foundation soil s u0 Obtained through in-situ testing.

4. The method for predicting lateral deformation of a foundation of a vacuum combined preloaded drainage board according to any one of claims 1 to 3, characterized in that: For plane strain conditions, the lateral strain under triaxial conditions needs to be converted into the lateral strain under plane strain conditions. Based on elastic theory, the lateral strain under plane strain conditions is converted from the lateral strain under triaxial conditions using the following formula: Where, ε hp is the lateral strain of soil under plane strain conditions, ε h is the lateral strain of soil under triaxial test conditions, and ν is the Poisson's ratio of soil.

5. The method for predicting lateral deformation of a foundation of a vacuum combined preloaded drainage board according to any one of claims 1 to 3, characterized in that: When calculating the dimensionless characteristic parameter β, the pile load p s is the maximum additional stress on the soil at each depth in the center of the preloading area under the maximum design load, which is calculated according to the calculation method of additional stress on the foundation in soil mechanics. v is the actual vacuum pressure of the soil at each depth in the center of the preloading area, and the initial vacuum pressure consolidation time t v The time from the start of vacuum pressure application to the start of load application, load application time t s It is the time from the beginning of the application of the load to the time it reaches the maximum design value.

6. The method for predicting lateral deformation of a foundation of a vacuum combined preloaded drainage board according to any one of claims 1 to 3, characterized in that: ε h / ε v1 -K e The quantitative relationship diagram of / K0 includes ε with and without prior vacuum consolidation time. h / ε v1 ~K e / K0, f(x) represents the relationship curve of ε under the combined preloading condition when the vacuum consolidation time is included and the vacuum consolidation time is not included. h / ε v1 and K e / K0 unified relationship: f(x)=a·f1(x)+b·f2(x) (14) f1(x)=-0.23+7.66e (-x / 0.19) (15) f2(x)=-0.159+11.04e (-x / 0.15) +1.03e (-x / 0.50) (16) Where f(x) represents ε under the unified relationship h / ε v1 The value of f1(x) represents the ε under the condition of prior vacuum consolidation time. h / ε v1 value, f2(x) represents the ε under the condition of no prior vacuum consolidation time h / ε v1 Value, x represents the ratio K e / K0, a and b are constants, and the values of a and b are 0.25 and 0.75 respectively.

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