A method for predicting lateral deformation of foundation with preloaded plastic drainage board

Abstract

The present invention discloses a method for predicting the lateral deformation of a plastic drain board foundation subjected to heap preloading, comprising the steps of calculating the representative stress ratio of the soil during heap preloading, calculating the reference vertical strain under one-dimensional compression conditions of the soil, calculating the ratio of the representative stress ratio to the coefficient of static earth pressure, calculating the ratio of the lateral strain to the one-dimensional compression 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 quantitative relationship diagram of the representative stress ratio of the soil during heap preloading, the ratio of the horizontal strain of the soil to the one-dimensional compression strain, and the ratio of the representative stress ratio of the soil to the coefficient of static earth pressure. The method can quickly calculate the lateral deformation of a plastic drain board foundation subjected to heap preloading, providing a reference for the design of drainage board foundations subjected to heap 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 preloaded plastic drainage board foundation. Background Art

[0002] Under preloading, plastic drain board foundations rapidly consolidate, often accompanied by significant deformation. Under surcharge preloading, plastic drain board foundations typically experience outward lateral deformation. Excessive outward lateral deformation can squeeze and damage adjacent structures, or even lead to embankment collapse. Therefore, effectively predicting the lateral deformation of drain board foundations under surcharge preloading is of great significance for engineering design and construction.

[0003] However, the current prediction methods for the lateral deformation of drainage board foundations under preload can only estimate the maximum lateral deformation of the foundation, but cannot predict the lateral deformation at different depths of the foundation, cannot analyze the lateral deformation of the foundation, and cannot determine the depth at which the maximum lateral deformation of the foundation occurs. The inventor's previously disclosed patent number is CN202310286028.5, and its name is a patent for a method for predicting the lateral deformation of a drainage board foundation under vacuum combined loading preloading. Although the lateral deformation of the drainage board foundation can be predicted, the above patent still has the following shortcomings: First, the scope of application is narrow, and it is only applicable to the working conditions of vacuum loading combined preloading, and cannot be extended to the prediction and calculation of the lateral deformation of the drainage board foundation under loading preloading; secondly, the key calculation steps are relatively cumbersome. When calculating the stress ratio of the foundation soil unit, the characteristic parameters must be calculated first, and then the relationship diagram between the stress ratio and the characteristic parameters is referred to to reversely calculate the soil stress ratio; the influencing factors are not considered comprehensively, and the influence of the key factor of horizontal additional stress in the foundation on the lateral deformation of the drainage board foundation is not considered, which increases the uncertainty of the prediction results to a certain extent.

[0004] In summary, developing a method that can predict the lateral deformation of the foundation of the preload-loaded drainage board is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for predicting the lateral deformation of a plastic drainage board foundation under preloading. The method is based on a quantitative relationship diagram of the representative stress ratio of the soil and the ratio of the horizontal strain / one-dimensional compression strain of the soil and the ratio of the representative stress ratio of the soil / static earth pressure coefficient during the preloading process. The method can quickly calculate the lateral deformation profile of the plastic drainage board foundation under preloading, providing a reference for the relevant design of the drainage board foundation treated by preloading.

[0006] To this end, the present invention provides a method for predicting the lateral deformation of a foundation of a preloaded plastic drainage board, comprising the following steps:

[0007] S1. Calculate the representative stress ratio K of the soil during the preloading process e *

[0008] According to the vertical additional stress p s , horizontal additional stress p h , surcharge loading rate LR, initial vertical effective stress of foundation soil σ v0 ′, initial horizontal effective stress σ of foundation soil h0 ′, and the related parameters of drainage board foundation consolidation and drainage, the representative stress ratio K of the soil during the preloading process is calculated by the following formula e * :

[0009]

[0010] 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 drainage board, μ is the dimensionless parameter related to the consolidation analysis of the drainage board foundation, and p a is the standard atmospheric pressure;

[0011] S2. Calculate the reference vertical strain ε under one-dimensional compression conditions of soil v1 , as follows:

[0012]

[0013] Where, e0 is the initial porosity of the soil, C c is the compression index, σ v0 ′ is the initial vertical effective stress of soil;

[0014] S3. Calculate the ratio K based on the known static earth pressure coefficient K0 of the soil. 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 :

[0015] f(x)=245.83e (-x / 0.10223 )+0.02943(4)

[0016] Where, 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;

[0017] Formula (4) is a calculation formula for the lateral strain of the foundation of the plastic drainage board under preloading with heap load established by the method of the present invention, which fills the deficiency that the relevant formulas in the existing methods cannot calculate the lateral strain of the drainage board foundation under heap load preloading.

[0018] S4: vertical strain ε under one-dimensional compression conditions calculated according to step S2 v1 and ε calculated in step S3 h / ε v1 value, calculate the lateral strain ε of the soil under triaxial test conditions h ;

[0019] S5, according to ε h The lateral deformation of the foundation is calculated according to the following formula:

[0020] δ=0.5Bε h (5)

[0021] Where δ is the lateral deformation of the soil.

[0022] Specifically, the representative stress ratio K e * Representative stress ratio under ideal instantaneous loading conditions As a basic term, the parameter α including the loading rate and soil consolidation characteristics is obtained jointly as a correction term; where,

[0023]

[0024] Where: is the representative stress ratio under ideal instantaneous loading conditions, T r is the time factor of radial consolidation; p a is the standard atmospheric pressure; t is the time; μ is the dimensionless factor considering the smearing effect and well resistance effect.

[0025] 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:

[0026] ε hp =(1+ν)ε h (9)

[0027] 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.

[0028] Specifically, calculate the representative stress ratio K e * When the vertical additional stress p s is the vertical 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 vertical additional stress of foundation in soil mechanics; h It is the additional horizontal stress on the soil at each depth 1 / 8 of the embankment width away from the center of the preloading area, calculated according to the calculation method of the horizontal additional stress of foundation in soil mechanics.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The method of the present invention directly establishes the representative stress ratio K of the drainage plate foundation soil unit in the preloading engineering e * The relationship between the main influencing factors does not require the participation of excess pore water pressure in the calculation, which simplifies the calculation steps, and the relationship diagram and relationship are concise and clear, making the method of the present invention calculate the representative stress ratio K e * Easier and faster;

[0031] 2. The method of the present invention takes into account the horizontal additional stress p for the working condition of pile load preloading. h The effect of this key factor increases the representative stress ratio K e * and the accuracy of the prediction results of foundation lateral deformation;

[0032] 3. The method of the present invention is aimed at the working condition of preloading with surcharge alone. The representative stress ratio K of the soil unit is analyzed based on the median point of excess pore water pressure during the consolidation stage of surcharge preloading. e * , and comprehensively consider the effects of the main influencing factors, establish a direct calculation of the representative stress K of the drainage plate foundation under the preload e * The expression of (i.e., formula (1)) shows that compared with the prediction method of lateral deformation of drainage board foundation under vacuum preloading, the stress ratio representative value selected by the method of the present invention is more consistent with engineering practice, which is conducive to increasing the reliability of the prediction results.

[0033] 4. This application uses the representative stress ratio K of the soil during the preloading process e * and ε h / εv1 (ε h is the lateral strain, ε v1 is the reference vertical strain under one-dimensional compression of soil) and K e * / K0(K e * The quantitative relationship diagram of the soil body (where K0 is the representative stress ratio of the soil during the preloading process and K0 is the static earth pressure coefficient of the soil) is used as the main body. The lateral deformation profile of the drainage board foundation under preloading can be quickly calculated, providing a reference for the relevant design of the drainage board foundation under preloading treatment.

[0034] In summary, the method of the present invention fills the deficiency of existing methods that are unable to predict and calculate the lateral deformation profile of the drainage board foundation under preloading alone, and establishes a calculation formula for the stress ratio based on the stress ratio corresponding to the median point of the excess pore water pressure of the plastic drainage board foundation during the preloading consolidation stage, which is more representative. When calculating the stress ratio of the foundation soil, there is no need to reversely infer based on the characteristic parameters, and the representative stress ratio of the foundation soil during the preloading process can be directly calculated, which simplifies the calculation process and steps. In addition, the effects of various major influencing factors including horizontal additional stress are comprehensively considered, and the prediction results are more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] 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.

[0036] Figure 1 This invention involves ε h / ε v1 With K e * / K0 quantitative relationship diagram;

[0037] Figure 2 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

[0038] 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.

[0039] The method for predicting the lateral deformation of a plastic drainage board foundation under heap preload provided by the present invention comprises the following steps:

[0040] S1. Calculate the representative stress ratio K of the soil during the preloading process e *

[0041] According to the vertical additional stress p s , horizontal additional stress p h , surcharge loading rate LR, initial vertical effective stress of foundation soil σ v0 ′, initial horizontal effective stress σ of foundation soil h0 ′, and the related parameters of drainage board foundation consolidation and drainage, the representative stress ratio K of the soil during the preloading process is calculated by the following formula e * :

[0042]

[0043] 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 drainage board, μ is the dimensionless parameter related to the consolidation analysis of the drainage board foundation, and p a is standard atmospheric pressure.

[0044] Among them, the representative stress ratio K e * The acquisition process is:

[0045] By stress ratio K e * From the definition, we know that K e * The size is directly affected by the load level (vertical and horizontal additional stress) and the soil excess pore water pressure. Under the same load conditions, the greater the excess pore water pressure, the greater the soil stress ratio K. e * Under the preloading load, according to the principle of soil mechanics, when the load is applied instantaneously, the excess pore water pressure of the soil reaches the maximum value and is proportional to the load p. s Equal, at this time, K calculated based on the median point of excess pore water pressure e * The theoretically achievable minimum When the excess pore water pressure dissipates halfway during the subsequent preloading consolidation stage (i.e., the median point of the excess pore water pressure), the vertical effective stress σ of the soil is v ′ and horizontal effective stress σ h ′ are shown in formula (10) and formula (11), respectively. Therefore, the representative stress ratio under ideal instantaneous loading conditions is The calculation formula is shown in formula (12).

[0046] σ v ′=σ v0 ′+p s -0.5p s =σ v0 ′+0.5p s (10)

[0047] σ h ′=σ h0 ′+p h -0.5p s (11)

[0048]

[0049] The physical meaning of the expression is clear, reflecting the influence of load size and initial stress of soil on the stress state of soil, and can be used as the soil stress ratio K under surcharge preloading. e * However, in actual engineering, the roadbed fill load is not applied instantaneously, but corresponds to a certain loading construction period. During this period, due to the drainage and consolidation of the soil, its maximum excess pore water pressure is often less than the loading size, that is, the actual engineering K e * Greater than ideal transient loading conditions Therefore, in the representative stress ratio K e * The impact of soil drainage and consolidation during the loading process should be considered in the assessment of the load. The main influencing factors are the loading rate and the soil consolidation properties. To address this, a dimensionless parameter proposed by CHAI and RONDONUWU et al. is introduced to comprehensively reflect the influence of the loading rate and soil consolidation properties.

[0050]

[0051] Where: T r is the time factor of radial consolidation; p a is the standard atmospheric pressure; t is the time; μ is the dimensionless factor considering the smearing effect and well resistance effect; r s and k s are the radius and permeability coefficient of the coating area respectively; l is the length of PVD (drainage board); q wPVD drainage capacity.

[0052] From the above analysis, we can see that and α include the soil stress ratio K under surcharge preloading e * Therefore, this patent is based on and α are basic parameters to explore the influence of soil stress ratio K e * It is well known that when the load size and the initial stress conditions of the soil are determined, the stress ratio K e * As the loading rate increases, it gradually decreases and eventually tends to Therefore, it is advisable to take As the basic term, the parameter α, which includes the loading rate and soil consolidation characteristics, is used as a correction term. The correction term should be greater than 1.0 and the expression should conform to the stress ratio K e * The increasing and decreasing trend with the change of related variables. Finally, the representative stress K shown in formula (1) is proposed e * The calculation formula of K is given by taking into account the influence of various major factors on K. e * The impact effect.

[0053] S2. Calculate the reference vertical strain ε under one-dimensional compression conditions of soil v1 , as follows:

[0054]

[0055] Where, e0 is the initial porosity of the soil, C c is the compression index, σ v0 ′ is the initial vertical effective stress of soil;

[0056] S3. Calculate the ratio K based on the known static earth pressure coefficient K0 of the soil. 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 :

[0057] f(x)=245.83e (-x / 0.10223) +0.02943 (4)

[0058] Where, ε h is the lateral strain of the soil, f(x) represents ε h / εv1 The value of x represents the ratio K e * / K0;

[0059] Formula (4) is the calculation formula for the lateral strain of the foundation of the plastic drainage board under preloading by the method of the present invention, which fills the deficiency that the relevant formulas in the existing methods cannot calculate the lateral strain of the drainage board foundation under preloading.

[0060] S4, vertical strain ε under one-dimensional compression condition calculated according to step S2 v1 and ε calculated in step S3 h / ε v1 Calculate the lateral strain ε of the soil under triaxial test conditions h ;

[0061] S5, according to ε h The lateral deformation of the foundation is calculated according to the following formula:

[0062] δ=0.5Bε h (5)

[0063] Where δ is the lateral deformation of the soil.

[0064] The lateral deformation of the foundation at different burial depths can be obtained by formula (5). The lateral deformation profile of the plastic drainage board foundation under load preloading can be obtained by using the obtained lateral deformation at different burial depths. Among them, the subscripts such as h and s involved in each parameter are dimensionless parameters and have no specific meaning. They are only used to distinguish the definitions of each parameter.

[0065] This application is based on a quantitative relationship diagram of the representative stress ratio of the soil and the ratio of the horizontal strain / one-dimensional compressive strain of the soil to the ratio of the representative stress ratio of the soil / static earth pressure coefficient during the preloading process. It can quickly and accurately calculate the lateral deformation profile of the plastic drainage board foundation under preloading, making up for the deficiency of the existing method that can only predict the maximum lateral deformation of the drainage board foundation under preloading but cannot calculate its lateral deformation, and provides a reference for the relevant design of the drainage board foundation under preloading treatment.

[0066] 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:

[0067] ε hp =(1+ν)ε h (9)

[0068] Where, ε hpis 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.

[0069] Specifically, calculate the representative stress ratio K e * When the vertical additional stress p s is the vertical 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 vertical additional stress of foundation in soil mechanics; h It is the additional horizontal stress on the soil at each depth 1 / 8 of the embankment width away from the center of the preloading area, calculated according to the calculation method of the horizontal additional stress of foundation in soil mechanics.

[0070] Compared with the inventor's previous method for predicting lateral deformation of drainage board foundation under vacuum preloading (Patent No. CN202310286028.5), the method of the present invention has the following essential differences:

[0071] 1. The calculation ideas and formulas of stress ratio are different: The prediction method of lateral deformation profile of drainage board foundation under vacuum preloading introduces a dimensionless characteristic parameter β by comprehensively considering various major factors, and reversely calculates the stress ratio K based on the empirical relationship diagram between stress ratio and characteristic parameter. e ; Establish stress K e When the stress ratio K is related to the characteristic parameter β, e The excess pore water pressure of the soil unit at the end of the loading is calculated based on the applied vacuum pressure, the loading and the simulation analysis. The method of the present invention directly establishes the representative stress ratio K of the drainage board foundation soil unit in the loading preloading project. e * The relationship between the main influencing factors does not require the participation of excess pore water pressure in the calculation, which simplifies the calculation steps, and the relationship diagram and relationship are concise and clear, making the method of the present invention calculate the representative stress ratio K e * Easier and faster;

[0072] 2. Different influencing factors are considered: The prediction method of the lateral deformation profile of the drainage board foundation under vacuum preloading mainly considers the vertical additional stress p s , vacuum pressure p v , the impact of factors such as the loading rate LR. The method of the present invention is aimed at the working condition of the preloading, and further considers the horizontal additional stress p h The effect of this key factor increases the representative stress ratio K e * and the accuracy of the prediction results of foundation lateral deformation;

[0073] 3. The representative value of stress ratio is selected differently: The prediction method of lateral deformation profile of drainage board foundation under vacuum preloading mainly calculates the stress ratio at the end of preloading as the representative value K by reading the excess pore water pressure value at the end of preloading. e , and then establish K e The method of the present invention is aimed at the working condition of preloading with surcharge alone, and analyzes the representative stress ratio K of the soil unit based on the median point of excess pore water pressure in the consolidation stage of surcharge preloading. e * , and comprehensively consider the effects of the main influencing factors, establish a direct calculation of the representative stress K of the drainage plate foundation under the preload e * Compared with the prediction method of the lateral deformation profile of the drainage board foundation under vacuum preloading, the stress ratio representative value selected by the method of the present invention is more in line with engineering practice, which is conducive to increasing the reliability of the prediction results.

[0074] In order to verify the reliability of the method of the present application, the method of the present invention was applied to the lateral deformation calculation in multiple actual engineering cases, and common engineering practices were considered more comprehensively. The verification analysis showed that the predicted values ​​of the lateral deformation were in good agreement with the measured values, the predicted lateral deformation trend and curve were basically consistent, and the measured lateral curve was generally within the predicted lateral deformation range, which verified the effectiveness and applicability of the method.

[0075] The following is a brief description of one of the engineering cases: This project is a roadbed project, the embankment and stratum cross-section and parameters are as follows: Figure 2 As shown in the figure, γ t is the soil weight; e0 is the initial porosity of the soil; C c is the soil compression index; c v and c h are the vertical and horizontal consolidation coefficients of the soil at the corresponding burial depth; k h is the horizontal permeability coefficient of the soil at the corresponding burial depth; ν is the Poisson's ratio of the soil at the corresponding burial depth; is the effective internal friction angle of the soil at the corresponding burial depth; OCR is the overconsolidation ratio of the soil. The surface layer of the foundation is 2m thick with sub-clay, and the second layer is 23m thick with silty clay, which is also the main weak layer. The top of the embankment is 28m wide and about 5m high, with a slope of 1:2 and a fill weight of about 20kN / m. 3 The final load is about 96kPa. It takes 250 days to fill to the design height, with an average load rate of about 0.39kPa / day. The plastic drainage board is laid out in a plum blossom pattern, with a depth of 25m and a spacing of 1.2m. The equivalent diameter of the drainage board is d w The diameter of the coating area is 0.052m, d sThe diameter of the PVD impact range is 0.25m, d e The permeability coefficient ratio of the smeared area to the non-smeared area is 1 / 10, and the drainage capacity of the drainage board is q w 50m 3 / year. The static earth pressure coefficient K0 of soil is calculated by the effective internal friction angle. calculate.

[0076] After calculation, Figure 1 Medium h / ε v1 -K e * The calculated lateral deformation values ​​at depths of 4m and 9m obtained from the K0 / K1 relationship analysis were 0.123m and 0.113m, respectively (lateral deformation was toward the outside of the roadbed). The errors from the measured values ​​of 0.127m and 0.106m were 3% and 6%, respectively, indicating that the calculated values ​​were in good agreement with the measured values.

[0077] 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 foundation with preloaded plastic drainage boards, characterized in that: The steps include: S1. Calculate the representative stress ratio K of the soil during the preloading process e * According to the vertical additional stress p s , horizontal additional stress p h , surcharge loading rate LR, initial vertical effective stress of foundation soil σ v0 ′, initial horizontal effective stress σ of foundation soil h0 ′ and the related parameters of the plastic drainage board foundation consolidation drainage, the representative stress ratio K of the soil during the preloading process is calculated by the following formula e * : 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 soil in the non-smearing area, k s is the permeability coefficient of the soil in the smear area, l is the length of the drainage board, μ1 is the dimensionless parameter related to the consolidation analysis of the drainage board foundation, and p a is the standard atmospheric pressure; S2. Calculate the reference vertical strain ε under one-dimensional compression conditions of soil v1 , as follows: Where, e0 is the initial porosity of the soil, C c is the compression index, σ v0 ′ is the initial vertical effective stress of soil; S3. Calculate the ratio K based on the known static earth pressure coefficient K0 of the soil. 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)=245.83e (-x / 0.10223) +0.02943 (4) Where, 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; S4: vertical strain ε under one-dimensional compression conditions calculated according to step S2 v1 and ε calculated in step S3 h / ε v1 value, calculate the lateral strain ε of the soil under triaxial test conditions h ; S5, according to ε h The lateral deformation of the foundation is calculated according to the following formula: δ=0.5Vε h (5) Where δ is the lateral deformation of the soil.

2. The method for predicting lateral deformation of a foundation of a preloaded plastic drainage board according to claim 1 is characterized by: Representative stress ratio K e * Representative stress ratio under ideal instantaneous loading conditions As a basic term, the parameter α including the loading rate and soil consolidation characteristics is obtained jointly as a correction term; where, Where: is the representative stress ratio under ideal instantaneous loading conditions, T r is the time factor of radial consolidation; p a is the standard atmospheric pressure; t is the time; μ2 is the dimensionless factor considering the smearing effect and well resistance effect.

3. The method for predicting lateral deformation of a foundation of a preloaded plastic drainage board according to claim 1 or 2, 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: e hp =(1+ν)e h (9) 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.

4. The method for predicting lateral deformation of a foundation of a preloaded plastic drainage board according to claim 1 or 2, characterized in that: Calculate the representative stress ratio K e * When the vertical additional stress p s is the vertical 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 vertical additional stress of foundation in soil mechanics; h It is the additional horizontal stress on the soil at each depth 1 / 8 of the embankment width away from the center of the preloading area, calculated according to the calculation method of the horizontal additional stress of foundation in soil mechanics.

5. The method for predicting lateral deformation of a foundation of a preloaded plastic drainage board according to claim 1 or 2, characterized in that: After using formula (5) to obtain the lateral deformation of the foundation at different burial depths, the lateral deformation profile of the plastic drainage board foundation under heap preloading can be obtained using the obtained lateral deformation at different burial depths.

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