A method for estimating pressure transfer effect of fill soil adjacent to bridge foundation

Abstract

The present invention discloses a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation, which relates to the technical field of fill, including studying the influence of airport fill loading on the mechanical response of a close-range bridge foundation; defining the pressure transfer coefficient β of the fill loading to the adjacent bridge foundation soil, and summarizing the influencing factors of the soil pressure transfer coefficient β into three parts; performing numerical simulation calculation and analysis through MIDAS GTS NX, establishing a three-dimensional numerical analysis model, studying the influence of the three major factors of "upper", "middle" and "lower" on the soil pressure transfer coefficient β, and obtaining the influence law of the soil pressure transfer coefficient β; obtaining a regression equation through regression analysis, and proposing a modified Coulomb formula based on the Coulomb theory soil pressure formula; comparing and analyzing the model test with the numerical analysis results, and verifying the rationality of the formula through theoretical calculation and finite element results. The present invention adopts the above-mentioned method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation, which can provide scientific guidance for engineering.

Description

Technical Field

[0001] The invention relates to the technical field of filling, in particular to a method for estimating the pressure transfer effect of filling soil adjacent to a bridge foundation. Background Art

[0002] During the expansion of an airport, a high fill expansion project was encountered. The outdoor floor of the planned Terminal 3 building was approximately 2167.30 m high, while the road system to its south was approximately 2148.70 m high. This resulted in a fill slope with a total height of approximately 18.6 m between the terminal building and the road. The lateral earth pressure generated by the fill (approximately 20 m) caused horizontal displacement of the support piles on the high fill slope, which in turn transferred the earth pressure to the adjacent bridge foundation cap, affecting its stability.

[0003] Currently, there is limited research on similar geotechnical engineering issues, both domestically and internationally. To ensure the overall safety and stability of airport high fill and bridge foundation systems while also conserving investment, further research is needed to understand the effect of soil pressure transfer from airport high fill slope support piles to adjacent bridge foundation abutments. This paper explores the mechanism of soil pressure transfer from airport fill to adjacent bridge foundations through theoretical analysis and numerical simulation, aiming to provide scientific guidance for similar projects. Summary of the Invention

[0004] The present invention proposes a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation to solve the problems mentioned in the above technical background.

[0005] To achieve the above object, the present invention proposes a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation, comprising the following steps:

[0006] S1. Study the effect of airport fill loading on the mechanical response of close-range bridge foundations;

[0007] S2. Define the earth pressure transfer coefficient β from the fill load to the adjacent bridge foundation, and summarize the influencing factors of the earth pressure transfer coefficient β into three major factors: "upper, middle, and lower": "upper" factors include the fill height H, fill cement content δ, original foundation slope α, and platform width L; "middle" factors include the distance D between the bridge foundation and the retaining wall pile foundation; "lower" factors include the reinforcement thickness h of the weak foundation, the diameter d of the cement-soil mixing piles, the spacing s between the cement-soil mixing piles, and the cement-soil strength f of the cement-soil mixing piles. cu ;

[0008] S3. Numerical simulation and analysis were performed using MIDAS GTS NX. A three-dimensional numerical analysis model was established to study the effects of the upper, middle, and lower factors and their corresponding nine factors on the earth pressure transfer coefficient β. The influence patterns of the upper, middle, and lower factors on the earth pressure transfer coefficient β were obtained.

[0009] S4. Through regression analysis, the regression equations of the soil pressure transfer coefficient β under the "upper" factor, "middle" factor and "lower" factor are obtained. Based on the Coulomb theory soil pressure formula, a modified Coulomb formula for the soil pressure of the existing bridge foundation due to adjacent loading is proposed; the model test results are compared with the numerical analysis results, and the rationality of the formula is verified by comparing the theoretical calculation with the finite element results.

[0010] Preferably, the formula for the earth pressure transfer coefficient β is as follows:

[0011]

[0012] Where E1 is the resultant lateral earth pressure of the retaining wall, and E2 is the lateral earth pressure of the bridge cap, both in kN·m -1 , used to solve the design problem of soil pressure near bridge foundation.

[0013] Preferably, S3 establishes a three-dimensional numerical analysis model as follows:

[0014] S31. Generate a geometric model. The three-dimensional model has an X-axis length of 113 m, a Y-axis length of 44.5 m, and a model height of 86.3 m. Both the bridge pile foundation and the retaining wall pile foundation are circular piles.

[0015] S32: Generate unit meshes. Automatically generate 3D meshes for the soil, foundations, and retaining walls using the Auto-Solid function. Use the hybrid mesh generator for meshing, with a basic mesh size of 5 m. Automatically generate 1D meshes for bridge and retaining wall pile foundations using beam element simulation and the Auto-Line function for meshing, with a basic mesh size of 3.2 m.

[0016] S33. Select gravity load and specify the model boundary conditions. The model boundary conditions are as follows: ① The top of the high fill and the ground surface are free boundaries without any constraints; ② The left and right sides of the model are constrained for displacement in the X direction; ③ The front and rear sides are constrained for displacement in the Y direction; ④ The bottom of the model is restricted for displacement in three directions;

[0017] S34, construction stage management, uses static / slope analysis to manage construction stages and create stress type construction stage groups;

[0018] S35, select the calculation parameters, select γ-fill bulk density, e-porosity, E-elastic modulus, ν-Poisson's ratio, c-cohesion and - Angle of internal friction is selected as the ground parameter, E-elastic modulus and ν-Poisson's ratio are selected as concrete parameters;

[0019] S36. Study the numerical scheme of the effects of “upper” factors, “middle” factors and “lower” factors on soil pressure transfer, and obtain the influence rules of “upper” factors, “middle” factors and “lower” factors on soil pressure transfer coefficient β.

[0020] Preferably, the construction phase group of S34 includes the following 6:

[0021] Ground stress balance: The natural stress field existing before construction is called the initial ground stress field. During the finite element calculation process, the initial ground stress generated by the self-weight stress is simulated by clearing the displacement of the initial ground stress field.

[0022] Retaining wall pile foundation construction: Activate the retaining wall pile foundation-1D grid group to simulate the retaining wall pile foundation construction;

[0023] Foundation pit excavation: passivate the foundation pit excavation range grid group and the foundation pile grid group, and simulate the foundation pit excavation;

[0024] Bridge foundation and abutment construction: In this construction stage group, activate the bridge pile foundation-1D grid group, the abutment grid group, and the column grid group on the abutment. Activate the abutment to change the attribute boundary to simulate the construction of bridge pile foundation and abutment.

[0025] Foundation pit backfill and retaining wall construction: Reactivate the foundation pit excavation range grid group, activate the slope cutting range grid group, retaining wall grid group, and retaining wall pile foundation grid group, activate the retaining wall base to change the attribute boundary, and simulate foundation pit backfill and retaining wall construction;

[0026] Fill construction: Activate the fill grid group to simulate the layered filling construction.

[0027] Preferably, the Coulomb theory earth pressure formula for clay soil in S4 is as follows:

[0028]

[0029] Among them, P a is the active earth pressure, γ is the fill density, H0 is the height of the retaining wall, K a is the active earth pressure coefficient, α0 is the angle between the vertical line and the retaining wall surface, β0 is the angle between the horizontal plane and the retaining wall surface, is the internal friction angle, δ0 is the friction angle between the fill and the retaining wall, K q is the overload coefficient, q is the standard value of the uniformly distributed surface load, η is the cohesion influence coefficient, and c is the cohesion of the soil.

[0030] The preferred formula for the modified Coulomb earth pressure of the “upper” factor on the adjacent bridge foundation is as follows:

[0031] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the fill height H is obtained as follows:

[0032] E a =β·P a =[-0.208ln(H)+1.1341]P a ;

[0033] By introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the filler cement content δ is obtained as follows:

[0034] E a =(-0.0076δ+0.5319)·P a ;

[0035] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the original foundation slope α is obtained as follows:

[0036]

[0037] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the platform width L is obtained as follows:

[0038] E a =[0.4784e 0.0094 L]·P a .

[0039] The preferred formula for the modified Coulomb earth pressure of the “middle” factor on the adjacent bridge foundation is as follows:

[0040] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation, considering the distance D between the bridge foundation and the supporting piles, is obtained as follows:

[0041] E a =(0.5119D -0.101 )·P a .

[0042] The preferred formula for the modified Coulomb earth pressure of the “lower” factor on the adjacent bridge foundation is as follows:

[0043] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the reinforcement thickness h is obtained as follows:

[0044] E a =(0.0115ln(h)+0.5183)·Pa ;

[0045] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the diameter d of the cement-soil mixing pile is obtained as follows:

[0046] E a =[0.0074ln(d)+0.3826]·P a ;

[0047] By introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the spacing s of cement-soil mixing piles is obtained as follows:

[0048] E a =(-0.003s+0.3824)·P a ;

[0049] The soil pressure transfer coefficient β is introduced into the Coulomb soil pressure formula to obtain the cement soil strength f of the cement soil mixing pile. cu Under these conditions, the modified Coulomb earth pressure formula of fill load on adjacent bridge foundation is as follows:

[0050] E a =[0.0081ln(f cu )+0.3755]·P a .

[0051] Therefore, the present invention adopts the above-mentioned method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation, which has the following beneficial effects:

[0052] (1) The concept of the soil pressure transfer coefficient β adjacent to the bridge foundation is proposed to facilitate the reasonable calculation and design of the soil pressure value adjacent to the bridge foundation;

[0053] (2) For the three major categories of "upper", "middle" and "lower", nine factors are used to propose the Coulomb formula for the correction of the soil pressure of the existing bridge foundation by the adjacent loading, which is convenient for designers to make reasonable calculations of the soil pressure of the bridge foundation.

[0054] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a flow chart of a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0056] Figure 2 Schematic diagram of the upper influencing factors of a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0057] Figure 3 This is an overall network diagram of a model for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0058] Figure 4 Schematic diagram of influencing factors in a method for estimating pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0059] Figure 5 Schematic diagram of the lower influencing factors of a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0060] Figure 6 A schematic diagram of soil pressure calculation for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0061] Figure 7 A comparison diagram of the theoretical formula of fill height H and the numerical simulation calculation results of a method for estimating the pressure transfer effect of fill soil near a bridge foundation according to the present invention;

[0062] Figure 8 A comparison chart of the theoretical formula for filler cement content δ and numerical simulation calculation results of a method for estimating the pressure transfer effect of fill soil near a bridge foundation according to the present invention;

[0063] Figure 9 A comparison diagram of the theoretical formula of the original foundation slope α and the numerical simulation calculation results of a method for estimating the pressure transfer effect of fill soil near a bridge foundation according to the present invention;

[0064] Figure 10 A comparison chart of the theoretical formula of platform width L and numerical simulation calculation results for a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0065] Figure 11 A comparison chart of the theoretical formula for the distance D between the bridge foundation and the supporting piles and the numerical simulation calculation results of a method for estimating the pressure transfer effect of fill soil near the bridge foundation according to the present invention;

[0066] Figure 12 A comparison chart of the theoretical formula for the thickness h of the reinforcement of soft foundation and the numerical simulation calculation results of a method for estimating the pressure transfer effect of fill soil near a bridge foundation according to the present invention;

[0067] Figure 13 A comparison chart of the theoretical formula for the diameter d of a cement-soil mixing pile and the numerical simulation calculation results of a method for estimating the pressure transfer effect of fill soil near a bridge foundation according to the present invention;

[0068] Figure 14 A comparison chart of the theoretical formula for the spacing s between cement-soil mixing piles and the numerical simulation calculation results for a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to the present invention;

[0069] Figure 15 The present invention is a method for estimating the pressure transmission effect of fill soil near the bridge foundation. cu Comparison chart of theoretical formula and numerical simulation results. DETAILED DESCRIPTION

[0070] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0071] like Figure 1 As shown in Figure 1, a method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation includes the following steps:

[0072] S1. Study the effect of airport fill loading on the mechanical response of close-range bridge foundations.

[0073] While theoretical earth pressure calculation methods can calculate earth pressure on fill retaining walls, they are unable to calculate earth pressure on bridge foundations. Directly using the earth pressure behind the retaining wall as the design value for earth pressure on the bridge foundation will result in an excessively large design load on the bridge foundation. Overemphasizing the retaining wall's supportive effect while ignoring the transfer of earth pressure from the retaining wall to the bridge foundation will result in an excessively small design load on the bridge foundation, inevitably having a significant impact on the bridge foundation. Currently, design results often exhibit these two extremes. However, the actual earth pressure acting on the adjacent bridge foundation must lie between these two loads. Therefore, the concept of the earth pressure transfer coefficient has been proposed.

[0074] S2. Define the earth pressure transfer coefficient β of the fill load to the adjacent bridge foundation, and summarize the factors affecting the earth pressure transfer coefficient β into three parts: the "upper" factors include the fill height H, the fill cement content δ, the original foundation slope α, and the platform width L; the "middle" factors include the distance D between the bridge foundation and the retaining wall pile foundation; and the "lower" factors include the soft foundation reinforcement thickness h, the cement soil mixing pile diameter d, the cement soil mixing pile spacing s, and the cement soil strength f of the cement soil mixing pile. cu .

[0075] like Figure 2 As shown in Figure 2, the formula for the earth pressure transfer coefficient β is as follows:

[0076]

[0077] Where E1 is the resultant lateral earth pressure of the retaining wall, and E2 is the lateral earth pressure of the bridge cap, both in kN·m -1 The transfer coefficient of fill load to bridge foundation soil pressure is the ratio of the resultant earth pressure of retaining wall to the resultant earth pressure of bridge foundation pedestal, which is used to solve the design problem of bridge foundation soil pressure caused by adjacent fill load.

[0078] S3. Numerical simulation and analysis were performed using MIDAS GTS NX, and a three-dimensional numerical analysis model was established to study the influence of the "upper" factor, "middle" factor, "lower" factor and their corresponding nine factors on the soil pressure transfer coefficient β. The influence law of the "upper" factor, "middle" factor and "lower" factor on the soil pressure transfer coefficient β was obtained.

[0079] MIDAS-GTS / NX allows for intuitive creation of complex 3D geometric models and provides a rich set of material constitutive models, unit libraries, and boundary conditions capable of simulating the constitutive relationships of most typical geotechnical materials. This example uses MIDAS-GTS NX for numerical simulation and analysis.

[0080] S31. Generate a geometric model. The 3D model is 113m long along the X-axis, 44.5m long along the Y-axis, and 86.3m high. Both the bridge and retaining wall foundations are circular piles; the bridge piles have a diameter of 1.5m and a length of 55m; the retaining wall piles have a diameter of 1m and a length of 46.2m. Type A retaining wall is 8m long, 22.5m wide, and 18m high, with 0.8m thick retaining wall panels and buttresses. Type B retaining wall is 3.9m long and 5.5m high. Bridge A cap is 10.3m long, 14.2m wide, and 3.5m high; bridge B cap is 10.3m long, 18.1m wide, and 5.1m high. The two caps are 16.8m apart and connected by a 3.6m wide, 2.6m high concrete beam.

[0081] S32, such as Figure 3 As shown, the unit grid is generated. The soil, foundation and retaining wall are automatically generated into 3D grids. The automatic-solid function is used for grid division. The hybrid grid generator is selected for division. The basic grid size is 5m. The bridge pile foundation and retaining wall pile foundation are automatically generated into 1D grids by beam unit simulation. The automatic-line function is used for grid division. The basic grid size is 3.2m.

[0082] S33. Select the gravity load and specify the model boundary conditions. The model has only one gravity load. Select the gravity load after meshing. The model boundary conditions are as follows: ① The top of the high fill and the ground surface are free boundaries, without any constraints; ② The left and right sides of the model constrain displacement in the X direction; ③ The front and rear sides constrain displacement in the Y direction; ④ The bottom of the model constrains displacement in three directions.

[0083] S34. Construction phase management uses static / slope analysis to conduct construction phase management and create stress type construction phase groups. Based on the design drawings of the terminal building foundation pit support and the slope support project on the south side of the terminal building for the third phase expansion project of a certain airport, the bridge and high fill construction are divided into multiple steps, including pile foundation construction and fill construction.

[0084] The numerical simulation of this embodiment sets the following 6 construction stage groups:

[0085] In-situ stress balance: The natural stress field existing before construction is called the initial in-situ stress field. During the finite element calculation process, the initial in-situ stress generated by self-weight stress is simulated by clearing the displacement of the initial in-situ stress field. In the initial construction step of the construction phase management group, MIDAS GTS activates the soil mesh groups of layers 1 to 4, the original fill mesh group, the pile cap mesh group, and the buttress retaining wall base mesh group. It also activates the displacement boundary and gravity load, selects the Clear Displacement option, and clears the initial stress and displacement of all elements, enabling simulation analysis of the initial in-situ stress field. Note: The attributes of the pile cap mesh group and buttress retaining wall base mesh group activated in this construction phase group are still the first-layer soil attribute parameters.

[0086] Retaining wall pile foundation construction: Activate the Retaining wall pile foundation-1D grid group to simulate the retaining wall pile foundation construction.

[0087] Foundation pit excavation: Passivate the foundation pit excavation range grid group and the foundation pile grid group to simulate foundation pit excavation.

[0088] Bridge foundation and abutment construction: In MIDAS GTS, you can modify mesh group properties using the Static / Slope Analysis, Boundary, and Change Properties functions. In this construction phase group, activate the Bridge Pile Foundation 1D mesh group, the Abutment mesh group, and the Abutment Column mesh group. Activate the Abutment Change Properties boundary to simulate the construction of the bridge pile foundation and abutment.

[0089] Foundation pit backfill and retaining wall construction: Reactivate the foundation pit excavation range grid group, activate the slope cutting range grid group, retaining wall grid group, and retaining wall pile foundation grid group, activate the retaining wall base to change the attribute boundary, and simulate the foundation pit backfill and retaining wall construction.

[0090] Fill Construction: Activate the fill grid group and simulate fill construction.

[0091] S35, select the calculation parameters, select γ-fill bulk density, e-porosity, E-elastic modulus, ν-Poisson's ratio, c-cohesion and -internal friction angle is selected as the formation parameter, E-elastic modulus and ν-Poisson's ratio are selected as concrete parameters.

[0092] In this numerical simulation, the isotropic elastic constitutive model was used for the bridge, retaining wall pile foundation, cap, retaining wall, and slope protection piles. The Mohr-Coulomb (MC) constitutive model was used for the geotechnical engineering survey report for the third phase expansion project of an airport. The formation parameters are shown in Table 1.

[0093] Table 1 Selection of formation parameters for numerical analysis

[0094]

[0095] The bridge pile foundation, abutment, and columns all use C40 concrete according to the bridge design report. The high fill support structure also uses C40 concrete according to the high fill support design report. The counter-pressure soil retaining wall uses C30 concrete. The concrete parameters are shown in Table 2.

[0096] Table 2 Concrete parameter selection

[0097] Concrete strength grade Elastic modulus E / GPa Poisson's ratio ν C30 30.0 0.167 C40 32.5 0.167 C50 34.5 0.167

[0098] S36. Study the numerical scheme of the effects of “upper” factors, “middle” factors and “lower” factors on soil pressure transfer, and obtain the influence rules of “upper” factors, “middle” factors and “lower” factors on soil pressure transfer coefficient β.

[0099] The influence of the upper factors of the airport high fill on the soil pressure transmission effect of the adjacent bridge foundation is studied. The main factors are as follows: fill height H, fill cement soil content δ, original foundation slope α, platform width L, etc. Figure 4 The specific numerical analysis scheme is shown in Table 3.

[0100] Table 3 Numerical schemes of upper influencing factors

[0101]

[0102] The influence of fill height H on the soil pressure transfer effect is studied. The fill properties are set as plain fill, original foundation slope α=1:2.0, platform width L=10m, and the influence of fill height H on the soil pressure transfer coefficient β is studied.

[0103] Taking H = 18m as an example, the lateral earth pressure on the retaining wall panel can be divided into three vertical stages. In the first stage (10-16m), the lateral earth pressure on the retaining wall panel is zero. In the second stage (2-10m), the lateral earth pressure on the retaining wall panel decreases linearly along the height of the wall. In the third stage (0-2m), the earth pressure curve shows an inflection point at 2m. In the first stage, lateral displacement of the fill causes separation between the wall and the soil, resulting in zero earth pressure on the retaining wall. The earth pressure distribution patterns in the second and third stages show slight fluctuations compared to traditional theoretical calculations. This is due to friction between the retaining wall back, ribs, and the fill, which inhibits the transmission of earth pressure and causes inflection.

[0104] As the fill height increases, the soil pressure on the abutment gradually increases. When the fill height H = 18-25, the maximum soil pressure on the abutment increases from 78.06 kPa to 126.16 kPa, an increase of 62%. This is because the load on the fill increases sharply as the fill height H increases, and the load transferred to the adjacent bridge foundation abutment also increases.

[0105] When the fill height H increases from 18m to 25m, the earth pressure on the retaining wall increases from 514.5kN·m -1 Increased to 978.8kN·m -1 , increased by 47.5%; the soil pressure of the foundation increased from 247.2kN·m -1 Increased to 455.54 kN·m -1 , an increase of 39.8%; the earth pressure transfer coefficient β decreased from 53% to 47%. As the fill load increases, the earth pressure on the fill retaining wall and the abutment increases in a coordinated manner. However, due to the hysteresis of the fill earth pressure transmission downward, the earth pressure on the lower abutment increases slightly, resulting in a gradual decrease in the earth pressure transfer coefficient.

[0106] Based on the above modeling process, the fill height is set to H = 18 m, the original foundation slope α = 1:2.0, and the platform width L = 10 m to study the effect of fill property δ on the earth pressure transfer coefficient.

[0107] When the filler material δ increases from δ = 0% to δ = 9%, the earth pressure distribution pattern on the retaining wall remains consistent, and the earth pressure gradually decreases. The maximum earth pressure decreases from 110kPa to 62kPa, a decrease of 43.6%. This is because the increase in the cement-soil content of the filler increases the strength and stiffness of the fill, enhances its self-stability, and reduces the lateral earth pressure on the retaining wall.

[0108] When the filler material δ increases from δ = 0% to δ = 9%, the soil pressure distribution pattern on the cap remains consistent, with the soil pressure gradually decreasing. The maximum soil pressure decreases from 78.1 kPa to 51.1 kPa, a decrease of 34.6%. This is because the increase in the cement-soil content in the filler increases the shear strength of the fill, weakens the fluidity of the fill, and reduces the lateral soil pressure on the cap.

[0109] When the cement content of filler is δ=0%~9%, the earth pressure of retaining wall is 514.5kN·m -1 Reduced to 414.1 kN·m -1 , reduced by 19.5%; the soil pressure of the foundation decreased from 247.2kN·m -1 Reduced to 193.4 kN·m -1 , decreased by 29.5%; the earth pressure transfer coefficient β decreased from 53% to 46%. The increase in fill cement content reduces the resultant earth pressure exerted by the fill load on the retaining wall and the foundation. However, due to the enhanced self-stability of the fill, the earth pressure transfer effect is weakened, resulting in a decrease in the earth pressure transfer coefficient.

[0110] Based on the above modeling process, the fill properties are set to plain fill, fill height H = 18m, and platform width L = 10m, and the influence of the original foundation slope α on the soil pressure transfer coefficient is studied.

[0111] When the original foundation slope α decreases from α = 1:1.5 to α = 1:2.0, the earth pressure distribution pattern of the retaining wall remains consistent, and the earth pressure gradually increases. The maximum value increases from 70.1 kPa to 80.4 kPa, an increase of 14.7%. This is because the original foundation slope α decreases, the fill volume in the fill area increases, the fill load increases, and the lateral earth pressure on the retaining wall increases.

[0112] When the original foundation slope α decreases from α = 1:1.5 to α = 1:2.0, the soil pressure distribution pattern at the cap remains consistent, and the soil pressure gradually increases, with the maximum value increasing from 74kPa to 78kPa, an increase of 5%. As the original foundation slope α decreases, the load at the fill increases, and the lateral soil pressure on the adjacent cap increases.

[0113] When the original foundation slope α is reduced from α=1:1.5 to α=1:2.0, the earth pressure of the retaining wall decreases from 487.2kN·m -1 Increased to 514.1 kN·m -1 , increased by 5.5%; the soil pressure of the foundation increased from 242.3kN·m -1 Increased to 274.3kN·m -1 , increased by 13.2%; the earth pressure transfer coefficient β increased from 49.7% to 53.3%. This is because the reduction of the original foundation slope α leads to an increase in the fill load, which in turn increases the earth pressure on the retaining wall and the foundation pile. However, the reduction of the original foundation slope causes the increase in earth pressure on the foundation pile to be greater than that on the retaining wall, which in turn increases the earth pressure transfer coefficient.

[0114] Based on the above modeling process, the fill properties are set to plain fill, the original foundation slope α = 1:2.0, and the fill height H = 18m. The effect of the platform width L on the soil pressure transfer coefficient is studied.

[0115] When the platform width L increases from L = 5m to L = 15m, the earth pressure distribution pattern on the retaining wall remains consistent, with the earth pressure gradually increasing. The maximum earth pressure increases from 68kPa to 74kPa, an increase of 8%. This is because the increase in platform width L increases the fill volume in the fill area and the fill load, which leads to an increase in the earth pressure exerted by the fill on the retaining wall.

[0116] When the platform width L increases from L = 5m to L = 15m, the soil pressure distribution pattern of the cap remains the same, and the soil pressure gradually increases. The maximum soil pressure increases from 65kPa to 79kPa, an increase of about 21%. This is because the increase in the fill load increases the lateral soil pressure on the cap.

[0117] When the platform width L increases from L = 5m to L = 15m, the earth pressure on the retaining wall increases from 485.1kN·m -1 Increased to 545.48 kN·m-1 , increased by 12.5%; the soil pressure of the foundation increased from 241.4kN·m -1 Increased to 298.4kN·m -1 , an increase of 23.6%; the earth pressure transfer coefficient β increased from 50% to 55%. The increase in platform width L increases the earth pressure on the retaining wall and the abutment, but the increase in abutment earth pressure is greater than that on the retaining wall with the increase in platform width, which leads to an increase in the earth pressure transfer coefficient.

[0118] The influence of the middle factors of the airport high fill on the soil pressure transmission effect of the adjacent bridge foundation is studied. The main factors are as follows: the influence of the distance D between the bridge foundation and the retaining wall pile foundation on the soil pressure transmission effect. Figure 5 The specific numerical analysis scheme is shown in Table 4.

[0119] Table 4 Numerical schemes of influencing factors in the middle

[0120]

[0121]

[0122] Based on the above modeling process, the influence of the horizontal distance D between fill and bridge foundation on the earth pressure transfer coefficient is studied.

[0123] When the horizontal distance D between the fill and the bridge foundation increases from D = 0.5m to D = 8m, the distribution pattern of earth pressure on the retaining wall remains the same, but the change in earth pressure is small. This shows that the change in the horizontal distance D between the fill and the bridge foundation has no effect on the lateral earth pressure on the retaining wall.

[0124] When the horizontal distance D between the fill and the bridge foundation increases from D = 0.5m to D = 8m, the distribution pattern of the soil pressure on the foundation remains consistent, and the soil pressure gradually decreases. The maximum soil pressure decreases from 151kPa to 72kPa, a decrease of 52%. This is because as the horizontal distance between the fill and the bridge foundation increases, the bridge foundation gradually moves away from the range of the fill load soil pressure.

[0125] When the horizontal distance D between the fill and the bridge foundation increases from D = 0.5m to D = 8m, the change range of the resultant earth pressure of the retaining wall is small, with a maximum difference of 1.3%; the resultant earth pressure of the foundation increases from 247.2kN·m -1 Reduced to 223.5kN·m -1 , decreased by 18.5%; the earth pressure transfer coefficient β decreased from 53% to 40%. The increase in the horizontal distance D between the fill and the bridge foundation does not affect the change in earth pressure on the retaining wall. However, as the bridge foundation gradually moves away from the range of the fill load earth pressure, the resultant earth pressure on the bridge foundation gradually decreases, resulting in a decrease in the earth pressure transfer coefficient.

[0126] The study investigated the influence of factors below the airport fill on the pressure transfer effect of the adjacent bridge foundation. The bridge foundation is located in a soft stratum and is reinforced with cement-soil mixing piles. The main factors are as follows: reinforcement thickness h, cement-soil mixing pile diameter d, cement-soil mixing pile spacing s, and cement-soil strength f of the cement-soil mixing piles. cu The lower diagram of the influencing factors is as follows: Figure 6 The specific numerical analysis scheme is shown in Table 5.

[0127] Table 5 Numerical schemes of the lower influencing factors

[0128]

[0129]

[0130] This embodiment uses the composite foundation method to simulate the reinforcement of weak strata. The mechanism of the composite foundation is to fully mobilize the soil between piles and the piles to jointly bear the load.

[0131] Based on the above modeling process and composite foundation equivalent method, cement soil mixing piles are used to strengthen the soft foundation. The diameter of the cement soil mixing piles is set to d = 0.6m, the pile spacing is s = 1.2m, and the cement soil strength f cu =1.5MPa. The effect of reinforcement depth h on soil pressure transfer coefficient of soft strata is studied.

[0132] When the reinforcement depth h of the soft stratum increases from h = 3m to h = 15m, the distribution of earth pressure remains the same, but the change in earth pressure is small. This shows that the change in the reinforcement depth h of the soft stratum has no effect on the lateral earth pressure of the retaining wall.

[0133] When the reinforcement depth h of the soft stratum increases from h = 3m to h = 15m, the distribution pattern of the earth pressure on the abutment remains consistent, with the earth pressure gradually increasing. The maximum earth pressure increases from 88.7kPa to 95.3kPa, a 3% increase. As the reinforcement depth h of the soft stratum increases, the area of ​​high-strength soil around the bridge foundation gradually increases, restricting the horizontal displacement of the abutment and causing the earth pressure on the abutment to increase.

[0134] When the reinforcement depth h of the soft stratum increases from h = 3m to h = 15m, the change range of the resultant earth pressure of the retaining wall is small, with a maximum difference of 1.3%; the resultant earth pressure of the foundation increases from 278.5kN·m -1 Increased to 306kN·m -1 , increased by 9.9%; the earth pressure transfer coefficient β increased from 53.1% to 54.9%. Increasing the reinforcement depth h of the soft stratum does not affect the earth pressure of the retaining wall, but it leads to an increase in the earth pressure of the bridge abutment, which in turn increases the earth pressure transfer coefficient.

[0135] Based on the above modeling process and composite foundation equivalent method, cement soil mixing piles are used to reinforce the soft foundation. The reinforcement depth of the soft foundation is set to h = 10m, the pile spacing is s = 1.2m, and the cement soil strength f cu =1.5MPa. The effect of the diameter d of cement-soil mixing pile foundation on the soil pressure transfer coefficient was studied.

[0136] When the diameter of the cement-soil mixing pile increases from d = 0.5 m to d = 0.8 m, the distribution of soil pressure remains the same, but the change in soil pressure is small, indicating that the change in pile diameter has no effect on the soil pressure of the retaining wall.

[0137] When the diameter of the cement-soil mixing pile increases from d = 0.5m to d = 0.8m, the distribution pattern of soil pressure on the abutment remains consistent, with soil pressure gradually increasing. The maximum soil pressure increases from 94.2kPa to 96.6kPa, a 1% increase. As the diameter d of the cement-soil mixing pile increases, the strength of the soil around the foundation increases, leading to an increase in soil pressure on the abutment.

[0138] When the diameter of cement-soil mixing pile increases from d = 0.5m to d = 0.8m, the change range of the resultant earth pressure of retaining wall is small, with the maximum difference of 1.3%. -1 Increased to 306kN·m -1 , an increase of 9.9%; the earth pressure transfer coefficient β increased from 37.7% to 38%. As the pile diameter increases, the reinforcement effect of the weak foundation is better, the stiffness of the reinforced foundation is greater, and the coordinated deformation of the weak foundation and the bridge foundation is smaller, resulting in greater earth pressure transmitted from the fill to the bridge foundation, which in turn increases the earth pressure transfer coefficient.

[0139] Based on the above modeling process and composite foundation equivalent method, cement soil mixing piles are used to reinforce the soft foundation. The reinforcement depth of the soft foundation is set to h = 10m, the diameter of the cement soil mixing pile foundation is d = 0.6m, and the cement soil strength f cu =1.5MPa. The effect of the spacing s between cement-soil mixing piles on the soil pressure transfer coefficient was studied.

[0140] When the spacing between cement-soil mixing piles increases from s = 1.0 m to s = 1.8 m, the distribution of earth pressure on the retaining wall remains consistent, but the change in earth pressure is small. This indicates that the change in the spacing between cement-soil mixing piles, s, has no effect on the lateral earth pressure on the retaining wall.

[0141] When the spacing between cement-soil mixing piles increases from s = 1.0 m to s = 1.8 m, the distribution of soil pressure on the abutment remains consistent, with soil pressure gradually decreasing, and the maximum soil pressure decreases from 96.2 kPa to 93.1 kPa. As the spacing between cement-soil mixing piles, s, increases, the strength of the soil around the foundation decreases, leading to a decrease in soil pressure on the abutment.

[0142] When the spacing between cement-soil mixing piles increases from s = 1.0m to s = 1.8m, the change range of the resultant earth pressure of the retaining wall is small, with a maximum difference of 1.3%; the resultant earth pressure of the foundation increases from 306kN·m -1 Reduced to 297kN·m -1 , decreased by 2.8%; the earth pressure transfer coefficient β decreased from 37.9% to 37.6%. As the pile spacing s increases, the reinforcement effect of the soft foundation becomes worse, the stiffness of the reinforced foundation decreases, and the coordinated deformation of the soft foundation and the bridge foundation increases. This results in a smaller earth pressure transferred to the bridge foundation in the fill direction, which in turn leads to a decrease in the earth pressure transfer coefficient.

[0143] Based on the above modeling process and composite foundation equivalent method, cement soil mixing piles are used to reinforce the soft foundation. The reinforcement depth of the soft foundation is set to h = 10m, the diameter of the cement soil mixing pile foundation is d = 0.6m, and the spacing between the cement soil mixing pile foundations is s = 1.2m. cu Influence on earth pressure transfer coefficient.

[0144] When the cement soil strength changes from f cu =0.5MPa increases to f cu =2.0MPa, the distribution of earth pressure on retaining wall is consistent, but the variation of earth pressure is small. cu The change of has no effect on the lateral earth pressure of the retaining wall.

[0145] When the cement soil strength changes from f cu =0.5MPa increases to f cu =2.0MPa, the soil pressure distribution of the foundation is consistent, the soil pressure gradually increases, and the maximum soil pressure increases from 88kPa to 96.6kPa, an increase of 9%. cu As the soil pressure increases, the strength of the soil around the bridge foundation increases, resulting in an increase in the soil pressure on the foundation.

[0146] Cement soil strength from f cu =0.5MPa increases to f cu =2.0MPa, the change range of the resultant earth pressure of the retaining wall is small, with a maximum difference of 1.3%; the resultant earth pressure of the foundation increases from 282kN·m -1 Increased to 308kN·m -1 The soil pressure transmission coefficient β increased from 37% to 38%. cu The increase of , the better the reinforcement effect of the soft foundation, the greater the foundation stiffness after reinforcement, the smaller the coordinated deformation of the soft foundation and the bridge foundation, resulting in a greater earth pressure transmitted to the bridge foundation in the fill direction, thereby increasing the earth pressure transfer coefficient.

[0147] The influence of the "upper" factor, "middle" factor and "lower" factor on the earth pressure transfer coefficient β is as follows: the earth pressure transfer coefficient β increases with the original foundation slope α, platform width L, reinforcement thickness h, cement soil mixing pile diameter d and cement soil strength f of the cement soil mixing pile. cu It gradually increases with the increase of fill height H, filler cement content δ, the distance D between the bridge foundation and the supporting piles, and the spacing s between cement-soil mixing piles.

[0148] S4. Through regression analysis, the regression equations of the soil pressure transfer coefficient β under the "upper" factor, "middle" factor and "lower" factor are obtained. Based on the Coulomb theory soil pressure formula, a modified Coulomb formula for the soil pressure of the existing bridge foundation due to adjacent loading is proposed; the model test results are compared with the numerical analysis results, and the rationality of the formula is verified by comparing the theoretical calculation with the finite element results.

[0149] The Coulomb theory earth pressure formula for clay soil is as follows:

[0150]

[0151] Among them, P a is the active earth pressure, γ is the fill density, H0 is the height of the retaining wall, K a is the active earth pressure coefficient, α0 is the angle between the vertical line and the retaining wall surface, β0 is the angle between the horizontal plane and the retaining wall surface, is the internal friction angle, δ0 is the friction angle between the fill and the retaining wall, K q is the overload coefficient, q is the standard value of the uniformly distributed surface load, η is the cohesion influence coefficient, and c is the cohesion of the soil.

[0152] The modified Coulomb earth pressure formula for the adjacent bridge foundation based on the “upper” factor is as follows:

[0153] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the fill height H is obtained as follows:

[0154] E a =β·P a =[-0.208ln(H)+1.1341]P a ;

[0155] For the earth pressure of the fill retaining wall, the result of the Coulomb earth pressure formula is recorded as E 1f , the numerical analysis results are recorded as E 1a , for the soil pressure on the foundation, the result of the modified Coulomb formula is recorded as E 2f , the numerical result is recorded as E 2a , compare the theoretical calculation results with the numerical analysis results, such as Figure 7As shown by Figure 7 As can be seen, the earth pressure E1 of the fill retaining wall obtained by numerical analysis and Coulomb's earth pressure calculation method is generally consistent. However, the Coulomb's earth pressure calculation formula cannot calculate the earth pressure E2 on the adjacent bridge foundation. The earth pressure on the adjacent bridge foundation obtained by the modified Coulomb's earth pressure formula proposed in this embodiment is generally consistent with the numerical simulation results, with an average error of 8.5%. This shows that the modified Coulomb's earth pressure calculation formula that takes into account the fill height in this embodiment is reasonable.

[0156] By introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the filler cement content δ is obtained as follows:

[0157] E a =(-0.0076δ+0.5319)·P a ;

[0158] Depend on Figure 8 It can be seen that the earth pressure on the adjacent bridge foundation obtained by the modified Coulomb earth pressure formula considering filler properties is consistent with the numerical simulation calculation results, with an average error of 11.2%, indicating that the modified Coulomb earth pressure calculation formula considering filler properties adopted in this embodiment is reasonable.

[0159] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the original foundation slope α is obtained as follows:

[0160]

[0161] Depend on Figure 9 It can be seen that the earth pressure on the adjacent bridge foundation obtained by the modified Coulomb earth pressure formula considering the original foundation slope is consistent with the numerical simulation calculation results of this embodiment, with an average error of 9.3%. This shows that the modified Coulomb earth pressure calculation formula considering the original foundation slope adopted in this embodiment is reasonable.

[0162] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the platform width L is obtained as follows:

[0163] E a =[0.4784e 0.0094 L]·P a .

[0164] Depend on Figure 10 It can be seen that the soil pressure on the adjacent bridge foundation obtained by the modified Coulomb's earth pressure formula considering the platform width is consistent with the numerical simulation calculation results of this embodiment, with an average error of 3.2%. This shows that the modified Coulomb's earth pressure calculation formula considering the platform width adopted in this embodiment is reasonable.

[0165] The modified Coulomb earth pressure formula for the adjacent bridge foundation based on the “middle” factor is as follows:

[0166] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation, considering the distance D between the bridge foundation and the retaining wall pile foundation, is obtained as follows:

[0167] E a =(0.5119D -0.101 )·P a .

[0168] Depend on Figure 11 It can be seen that the earth pressure on the bridge foundation adjacent to the modified Coulomb earth pressure formula considering the distance between the fill and the bridge foundation is consistent with the numerical simulation results of this embodiment, with an average error of 6.5%. This shows that the modified Coulomb earth pressure calculation formula considering the distance between the fill and the bridge foundation used in this embodiment is reasonable.

[0169] The modified Coulomb earth pressure formula for the adjacent bridge foundation based on the “lower” factor is as follows:

[0170] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the reinforcement thickness h is obtained as follows:

[0171] E a =(0.0115ln(h)+0.5183)·P a ;

[0172] Depend on Figure 12 It can be seen that the soil pressure on the adjacent bridge foundation obtained by the modified Coulomb's earth pressure formula considering the reinforcement depth of the soft foundation is consistent with the numerical simulation results of this embodiment, with an average error of 9.4%. This shows that the modified Coulomb's earth pressure calculation formula considering the reinforcement depth of the soft foundation adopted in this embodiment is reasonable.

[0173] Introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the diameter d of the cement-soil mixing pile is obtained as follows:

[0174] E a =[0.0074ln(d)+0.3826]·P a ;

[0175] Depend on Figure 13 It can be seen that the earth pressure on the adjacent bridge foundation obtained by the modified Coulomb earth pressure formula considering the diameter of the reinforcement piles is consistent with the numerical simulation results of this embodiment, with an average error of 5.2%. This shows that the modified Coulomb earth pressure calculation formula considering the diameter of the reinforcement piles used in this embodiment is reasonable.

[0176] By introducing the earth pressure transfer coefficient β into the Coulomb earth pressure formula, the modified Coulomb earth pressure formula for the fill load on the adjacent bridge foundation considering the spacing s of cement-soil mixing piles is obtained as follows:

[0177] E a =(-0.003s+0.3824)·P a ;

[0178] Depend on Figure 14 It can be seen that the earth pressure on the adjacent bridge foundation obtained by the modified Coulomb earth pressure formula considering the spacing between reinforced piles is consistent with the numerical simulation results of this embodiment, with an average error of 7.1%. This shows that the modified Coulomb earth pressure calculation formula considering the spacing between reinforced piles adopted in this embodiment is reasonable.

[0179] The soil pressure transfer coefficient β is introduced into the Coulomb soil pressure formula to obtain the cement soil strength f of the cement soil mixing pile. cu Under these conditions, the modified Coulomb earth pressure formula of fill load on adjacent bridge foundation is as follows:

[0180] E a =[0.0081ln(f cu )+0.3755]·P a .

[0181] Depend on Figure 15 It can be seen that the soil pressure on the adjacent bridge foundation obtained by the modified Coulomb's earth pressure formula considering the cement strength of the reinforced piles is consistent with the numerical simulation results of this embodiment, with an average error of 5.4%. This shows that the modified Coulomb's earth pressure calculation formula considering cement strength adopted in this embodiment is reasonable.

[0182] Therefore, the present invention adopts the above-mentioned method for estimating the pressure transfer effect of fill soil adjacent to the bridge foundation to study the pressure transfer mechanism of the airport fill soil adjacent to the bridge foundation, providing scientific guidance for similar projects.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation, characterized in that: The following steps are involved: S1. Study the effect of airport fill loading on the mechanical response of close-range bridge foundations; S2. Define the pressure transfer coefficient of fill load to adjacent bridge foundation soil , the formula is as follows: ； in, is the resultant lateral earth pressure on the retaining wall, is the lateral earth pressure of the bridge cap, and the units of both are , the earth pressure transfer coefficient The influencing factors are summarized into three major factors: upper, middle and lower factors: the upper factors include fill height , filler cement content , original foundation slope and platform width The middle factor includes the distance between the bridge foundation and the retaining wall pile foundation , the lower factors include the thickness of the soft foundation reinforcement , Cement soil mixing pile diameter , spacing between cement soil mixing piles and cement soil strength of cement soil mixing piles ; S3. Use MIDAS GTS NX to perform numerical simulation and analysis, establish a three-dimensional numerical analysis model, and study the effects of upper factors, middle factors, lower factors and their corresponding nine factors on the soil pressure transfer coefficient. The influence of the upper factor, middle factor and lower factor on the earth pressure transfer coefficient is obtained The influence of law; S4. Through regression analysis, the soil pressure transfer coefficient under the upper factor, middle factor and lower factor is obtained Based on the regression equation of Coulomb's theoretical earth pressure formula, a modified Coulomb's formula for the effect of adjacent loading on the earth pressure of existing bridge foundations is proposed; the model test results are compared with the numerical analysis results, and the rationality of the formula is verified by comparing the theoretical calculations with the finite element results.

2. The method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to claim 1, characterized in that: S3 establishes a three-dimensional numerical analysis model as follows: S31. Generate a geometric model. The three-dimensional model has an X-axis length of 113 m, a Y-axis length of 44.5 m, and a model height of 86.3 m. Both the bridge pile foundation and the retaining wall pile foundation are circular piles. S32: Generate unit meshes. Automatically generate 3D meshes for the soil, foundations, and retaining walls using the Auto-Solid function. Use the hybrid mesh generator for meshing, with a basic mesh size of 5 m. Automatically generate 1D meshes for bridge and retaining wall pile foundations using beam element simulation and the Auto-Line function for meshing, with a basic mesh size of 3.2 m. S33. Select gravity load and specify model boundary conditions; S34, construction stage management, uses static / slope analysis to manage construction stages and create stress type construction stage groups; S35, select calculation parameters, select Fill bulk density, Porosity ratio, Elastic modulus, Poisson's ratio, Cohesion and The internal friction angle is selected as the formation parameter. Elastic modulus and Poisson's ratio as a concrete parameter; S36, study the numerical scheme of the upper factor, middle factor and lower factor on the soil pressure transmission effect, and obtain the upper factor, middle factor and lower factor on the soil pressure transmission coefficient The influence rules.

3. The method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to claim 2, characterized in that: The construction phase groups of S34 include the following 6: Ground stress balance: The natural stress field existing before construction is called the initial ground stress field. During the finite element calculation process, the initial ground stress generated by the self-weight stress is simulated by clearing the displacement of the initial ground stress field. Retaining wall pile foundation construction: Activate the retaining wall pile foundation-1D grid group to simulate the retaining wall pile foundation construction; Foundation pit excavation: passivate the foundation pit excavation range grid group and the foundation pile grid group, and simulate the foundation pit excavation; Bridge foundation and abutment construction: In this construction stage group, activate the bridge pile foundation-1D grid group, the abutment grid group, and the column grid group on the abutment. Activate the abutment to change the attribute boundary to simulate the construction of bridge pile foundation and abutment. Foundation pit backfill and retaining wall construction: Reactivate the foundation pit excavation range grid group, activate the slope cutting range grid group, retaining wall grid group, and retaining wall pile foundation grid group, activate the retaining wall base to change the attribute boundary, and simulate foundation pit backfill and retaining wall construction; Fill construction: Activate the fill grid group to simulate the layered filling construction.

4. The method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to claim 2, characterized in that: The Coulomb theory earth pressure formula for clay soil in S4 is as follows: ； ； in, is the active earth pressure resultant, is the bulk density of fill soil, is the height of the retaining wall, is the active earth pressure coefficient, is the angle between the vertical line and the retaining wall surface, is the angle between the horizontal plane and the retaining wall surface. is the internal friction angle, is the friction angle between the fill and the retaining wall surface, is the overload factor, is the standard value of uniformly distributed load on the surface, is the cohesion influence coefficient, The cohesion of soil.

5. The method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to claim 4, characterized in that: The modified Coulomb earth pressure formula for the upper factors on the adjacent bridge foundation is as follows: Fill height The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: ； Filler cement content The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: ； Original foundation slope The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: ； Platform width The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: 。 6. The method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to claim 4, characterized in that: The modified Coulomb earth pressure formula of the central factor on the adjacent bridge foundation is as follows: Distance between bridge foundation and supporting piles The modified Coulomb earth pressure formula for the adjacent bridge foundation is: .

7. The method for estimating the pressure transfer effect of fill soil adjacent to a bridge foundation according to claim 4, characterized in that: The modified Coulomb earth pressure formula for the lower factor on the adjacent bridge foundation is as follows: Reinforcement thickness The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: ； Cement soil mixing pile diameter The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: ； Cement soil mixing pile spacing The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: ； Cement soil strength of cement soil mixing pile The modified Coulomb earth pressure formula for the adjacent bridge foundation is as follows: 。

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