Method for evaluating pore pressure of saturated sand based on permeability of weak permeable interlayer
By establishing a layered model and performing dynamic-fluid-structure interaction analysis, the problem of failing to consider the permeability differences of weakly permeable interlayers in existing technologies has been solved. This enables a systematic assessment of the entire pore water pressure process and a quantitative determination of liquefaction risk, thereby improving the accuracy of the assessment and the safety of the project.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU UNIV
- Filing Date
- 2026-01-22
- Publication Date
- 2026-04-24
AI Technical Summary
Existing pore pressure assessment methods fail to adequately consider the permeability differences of weakly permeable interlayers, resulting in discrepancies between assessment results and actual engineering conditions. They also lack a systematic assessment of the entire process of pore water pressure generation, accumulation, and dissipation.
A hierarchical model was established, and a dynamic fluid-structure interaction analysis model was constructed using finite difference mesh generation and dynamic constitutive model. The interlayer characteristics were reflected by the differential permeability coefficient parameter, the pore water pressure response and effective stress evolution were simulated, and the pore pressure ratio evaluation index was introduced for quantitative evaluation.
It enables systematic analysis of the entire pore water pressure process, improves the accuracy of evaluation results, can identify the pore pressure distribution characteristics of interlayer regions, and provides a reliable basis for foundation liquefaction resistance design.
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Figure CN121920149A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of dynamic analysis technology for saturated sand, specifically to a method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers. Background Technology
[0002] Under impact loads such as explosions and pile driving, as well as cyclic loads such as earthquakes and shaking tables, saturated sand will generate significant excess pore water pressure. The rapid accumulation of pore water pressure will lead to a significant reduction in the effective stress of the soil, which in turn will cause engineering problems such as liquefaction, subsidence and bearing capacity degradation. Engineering practice shows that weakly permeable interlayers such as silt interlayers and cohesive soil interlayers are common in actual foundations. Their permeability is significantly lower than that of the surrounding sand layer, which has a significant impact on the pore pressure transmission path and dissipation rate.
[0003] Existing research indicates that the generation, development, and dissipation of pore water pressure in saturated sand are not only related to the form, intensity, and duration of dynamic loads, but also closely related to the soil's permeability, layering structure, and drainage conditions. In practical engineering, foundations are often not homogeneous sand layers, but rather contain weakly permeable interlayers such as silt and cohesive soil layers with significantly lower permeability coefficients than sand. These weakly permeable interlayers alter the transmission path and dissipation rate of pore water pressure, significantly impacting the pore pressure response and liquefaction characteristics of saturated sand.
[0004] Most existing pore pressure assessment methods typically simplify the foundation as a homogeneous or equivalent homogeneous medium during the modeling process, failing to fully consider the impact of the permeability differences of weakly permeable interlayers on the evolution of pore water pressure. This leads to deviations between the assessment results and actual engineering conditions. They focus on a single dynamic condition or a single analysis stage, often only paying attention to the peak or accumulation process of pore water pressure, lacking a systematic assessment of the entire process of pore pressure generation, accumulation, and dissipation. Summary of the Invention
[0005] To address the shortcomings of the existing technologies, the present invention aims to provide a method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers. This method addresses the common practice in modeling where the foundation is often simplified to a homogeneous or equivalent homogeneous medium, failing to adequately consider the impact of differences in the permeability of weakly permeable interlayers on the evolution of pore water pressure. Consequently, the assessment results deviate from the actual engineering situation, often focusing only on the peak value or accumulation process of pore water pressure, lacking a systematic assessment of the entire process of pore pressure generation, accumulation, and dissipation.
[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: a method for assessing the pore pressure of saturated sand based on the permeability of weakly permeable interlayers, comprising the following steps:
[0007] Step S1: Taking saturated sand with a weakly permeable interlayer as the research object, establish a layered model composed of saturated sand and weakly permeable interlayer, and divide the saturated sand and weakly permeable interlayer into grids according to the finite difference grid division principle.
[0008] Step S2: For the liquefaction and deformation mechanism of saturated sand under dynamic loading, a dynamic constitutive model suitable for cyclic loading conditions is selected, and different permeability coefficient parameters are assigned to the saturated sand layer and the weakly permeable interlayer, respectively.
[0009] Step S3: Under the action of gravity, apply the self-weight load to the dynamic constitutive model to generate the initial stress field of the dynamic constitutive model, and establish the initial pore water pressure field according to the groundwater level conditions so that the dynamic constitutive model reaches the static equilibrium state before dynamic loading.
[0010] Step S4: Based on the finite difference theory, construct a dynamic fluid-structure interaction analysis model of the dynamic response control equation and the pore water seepage control equation of saturated sand, and solve the dynamic response and pore pressure evolution process of the soil simultaneously during the calculation process.
[0011] Step S5: Select impact load and cyclic load as dynamic load input according to the research purpose, and simulate the pore water pressure response of saturated sand under different dynamic conditions.
[0012] Step S6: Extract the pore water pressure and effective stress response results at different depths and locations in the model during dynamic loading to obtain the evolution law of pore pressure with time and space.
[0013] Step S7: By comparing the pore pressure development characteristics under different permeability coefficient conditions of weakly permeable interlayers, quantitatively assess the influence of the permeability of weakly permeable interlayers on the accumulation, dissipation and liquefaction response of saturated sand pore pressure, and form pore pressure assessment results.
[0014] Preferably, the weakly permeable interlayer is a silt layer and a clay layer with a permeability coefficient significantly lower than that of the upper and lower saturated sand layers. The layered model is established in a two-dimensional spatial form, and the layered model is spatially layered to clarify the thickness, burial depth and spatial distribution relationship of each soil layer.
[0015] Preferably, the dynamic constitutive model is an elastoplastic model suitable for cyclic loading conditions. The dynamic constitutive model describes the stress-strain relationship and the accumulation process of excess pore water pressure in saturated sand under stress cycle, and assigns a low permeability coefficient parameter to the weakly permeable interlayer. The weakly permeable interlayer forms a pore pressure transmission hindrance zone in the layered model.
[0016] Preferably, the initial pore water pressure field adopts a hydrostatic pressure distribution form.
[0017] Preferably, in the dynamic fluid-structure interaction analysis model, the weak permeability characteristics of the interlayer are reflected by the differentiated permeability coefficient parameter, and reasonable drainage boundary conditions are set.
[0018] Preferably, the impact load is used to simulate explosion, pile driving and short-term high-dynamic conditions, the cyclic load is used to simulate earthquake and shaking table loading conditions, and the dynamic load is applied to the model base or side boundary in the form of stress time history or velocity time history.
[0019] Preferably, the pore water pressure development curve and effective stress evolution path are extracted to determine the liquefaction process of saturated sand.
[0020] Preferably, the pore pressure development characteristics include a pore pressure development curve, pore pressure peak distribution, and dissipation rate.
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] This invention introduces the permeability difference of weakly permeable interlayers into the pore pressure assessment process. By constructing a coupled analysis model of saturated sand dynamic response and pore water seepage, it can accurately reflect the influence of weakly permeable interlayers on the generation, accumulation and dissipation of pore water pressure, thereby improving the accuracy of pore pressure assessment results.
[0023] This invention achieves a systematic analysis of the entire process of pore water pressure in saturated sand by unifying the modeling of dynamic response, seepage process and effective stress evolution, thus avoiding the problem of incomplete analysis results caused by existing methods that only evaluate a single stage.
[0024] This invention introduces evaluation indicators such as pore pressure ratio, combining pore water pressure with initial effective stress to achieve quantitative determination of liquefaction risk of saturated sand, which can provide a reliable basis for foundation anti-liquefaction design and engineering safety assessment.
[0025] This invention, through comparative analysis of pore water pressure at different spatial locations, can clearly identify the differences in pore pressure development between the upper and lower regions of a weakly permeable interlayer, revealing the spatial distribution characteristics of high-value and stagnant pore pressure zones near the interlayer. It is applicable to both impact load and cyclic load conditions, and only requires adjustment of the power input method to complete pore pressure assessment under different conditions, demonstrating strong versatility. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is the overall flowchart of the method of the present invention;
[0028] Figure 2 This is a flowchart of the modeling process for the weakly permeable interlayer in this invention.
[0029] Figure 3 This is a flowchart illustrating the generation process of the initial stress field and pore water pressure field in the method of this invention.
[0030] Figure 4 This is a flowchart of the dynamic fluid-structure interaction analysis method of the present invention;
[0031] Figure 5 This is a flowchart of the pore pressure assessment and liquefaction determination method of the present invention. Detailed Implementation
[0032] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.
[0033] Reference Figure 1-5 As shown, the method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to the present invention comprises the following steps:
[0034] Step S1: Taking saturated sand with weakly permeable interlayers as the research object, a layered model composed of saturated sand and weakly permeable interlayers is established. The weakly permeable interlayer is a silt layer and a clay layer with a permeability coefficient significantly lower than that of the upper and lower saturated sand layers. The interlayers are continuously distributed in the horizontal direction.
[0035] The saturated sand and the weakly permeable interlayer were divided into grids according to the finite difference grid principle. The grid was kept continuous at the junction of the weakly permeable interlayer and the saturated sand layer to ensure the continuous transmission of pore water pressure and seepage flow between the layers.
[0036] The layered model is a numerical model that accurately simulates the transmission and dissipation of pore water pressure by dividing complex foundation soil into different layers according to the differences in the physical properties of the soil layers. The core principles include physical layering basis, spatial structure representation and parameter differentiation assignment.
[0037] Based on the physical stratification, the foundation is divided into a saturated sandy soil layer and a weakly permeable interlayer according to the difference in the permeability coefficient of the soil layers. The permeability coefficient of the weakly permeable interlayer is significantly lower than that of the sandy soil layer, forming a pore pressure transmission hindrance zone.
[0038] Spatial structure characterization is established in a two-dimensional spatial form, clarifying the thickness, burial depth and spatial distribution relationship of each soil layer, and setting a horizontally continuous weakly permeable interlayer in the middle of homogeneous saturated sand.
[0039] Different parameter values were assigned to saturated sand layers and weakly permeable interlayers, respectively, and the differences in pore pressure evolution between layers were reflected by dynamic fluid-structure interaction analysis.
[0040] Step S2: For the liquefaction and deformation mechanism of saturated sand under dynamic loading, a dynamic constitutive model suitable for cyclic loading conditions is selected. The dynamic constitutive model is an elastoplastic model suitable for cyclic loading conditions. The dynamic constitutive model describes the stress-strain relationship and the accumulation process of excess pore water pressure of saturated sand under stress cyclic loading.
[0041] In the seepage analysis, different permeability coefficient parameters were assigned to the saturated sand layer and the weakly permeable interlayer, respectively. The weakly permeable interlayer was assigned a lower permeability coefficient parameter. The weakly permeable interlayer formed a pore pressure transmission hindrance zone in the layered model, thus reflecting the influence of the interlayer permeability difference on the pore pressure response.
[0042] Step S3: Under the action of gravity, apply the self-weight load to the dynamic constitutive model to generate the initial stress field of the dynamic constitutive model, and establish the initial pore water pressure field according to the groundwater level conditions so that the dynamic constitutive model reaches the static equilibrium state before dynamic loading.
[0043] The initial pore water pressure field adopts a hydrostatic pressure distribution form, and ensures the continuity of pore water pressure between the sand layer and the weakly permeable interlayer.
[0044] Step S4: Based on the finite difference theory, construct a dynamic fluid-structure interaction analysis model of the dynamic response control equation and the pore water seepage control equation of saturated sand, and solve the dynamic response and pore pressure evolution process of the soil simultaneously during the calculation process.
[0045] The finite difference theory is a numerical method for solving differential equations by discretizing continuous mathematical models. Its core idea is to divide the continuous spatial and time domains into discrete grids, use difference approximations to replace derivatives, and transform partial differential equations into a system of algebraic equations for solution.
[0046] The dynamic response control equation is expressed as follows:
[0047]
[0048] in: This indicates the density of saturated sandy soil; Indicates displacement components; Represents the total stress tensor; Represents the components of gravitational acceleration; Indicates time;
[0049] The governing equation for pore water seepage is expressed as follows:
[0050]
[0051]
[0052]
[0053] in: Represents the effective stress tensor; Indicates pore water pressure; Represents the Kronecker symbol; Indicates the volume compressibility factor; Represents the seepage velocity vector; Indicates the permeability coefficient; Indicates hydraulic potential;
[0054] In the dynamic fluid-structure interaction analysis model, the weak permeability characteristics of the interlayer are reflected by the differentiated permeability coefficient parameter, and reasonable drainage boundary conditions are set to simulate the dissipation process of pore pressure under dynamic action.
[0055] Step S5: Select impact load and cyclic load as dynamic load input according to the research purpose, and simulate the pore water pressure response of saturated sand under different dynamic conditions.
[0056] The impact load is used to simulate explosion, pile driving and short-term high dynamic conditions, the cyclic load is used to simulate earthquake and shaking table loading conditions, and the dynamic load is applied to the model base or side boundary in the form of stress time history or velocity time history. The differences in pore pressure response under the condition of weak permeability interlayer are analyzed by setting different working conditions.
[0057] Step S6: Extract the pore water pressure and effective stress response results at different depths and locations in the model during dynamic loading to obtain the evolution law of pore pressure with time and space.
[0058] The pore water pressure development curve and effective stress evolution path were extracted to determine the liquefaction process of saturated sand.
[0059] The cumulative pore water pressure can be expressed as a functional relationship between dynamic stress and permeability conditions:
[0060]
[0061] in: Indicates the increment of superstatic pore pressure; This indicates the amplitude of cyclic stress or impact stress; Indicates the number of cycles or equivalent impacts; Indicates the permeability coefficient;
[0062] Step S7: By comparing the pore pressure development characteristics under different permeability coefficients of weakly permeable interlayers, quantitatively assess the influence of the permeability of weakly permeable interlayers on the accumulation, dissipation and liquefaction response of saturated sand pore pressure, and form pore pressure assessment results;
[0063] The pore pressure development characteristics include the pore pressure development curve, pore pressure peak distribution, and dissipation rate;
[0064] To quantitatively assess pore pressure levels, the pore pressure ratio is introduced as an evaluation index.
[0065]
[0066] in: Indicates the pore pressure ratio; Indicates the pressure of excess pore water; Indicates the initial effective stress;
[0067] When the pore pressure ratio is close to 1, it indicates that the effective stress of the soil is significantly reduced, and there is a risk of liquefaction.
[0068] The following detailed description of the pore pressure assessment method for saturated sand based on the permeability of weakly permeable interlayers proposed in this invention, with reference to specific embodiments, is provided below.
[0069] Example: Assessment of pore pressure in saturated sand under conditions of weakly permeable interlayers
[0070] 1. A typical saturated sandy soil foundation was selected as the research object. A continuously distributed weakly permeable interlayer was set in the middle of the homogeneous saturated sandy soil to simulate the silt or clay interlayer commonly seen in actual engineering.
[0071] The model is built in two-dimensional plane strain form. The model width is 30m and the height is 15m. The bottom is fixed, the left and right boundaries are set as horizontal displacement constraints, and the top is a free drainage boundary.
[0072] The saturated sand consists of a lower saturated sand layer, a weakly permeable interlayer, and an upper saturated sand layer from bottom to top. The weakly permeable interlayer is located in the middle of the model, with a thickness of 0.8m and a burial depth ranging from 6.0 to 6.8m.
[0073] The model area was meshed using the finite difference method, with a unit size of 0.25m × 0.25m, and a total of about 7200 units were divided. Mesh continuity was ensured at the interface between the sand layer and the weakly permeable interlayer to ensure the continuity of pore water pressure and seepage flow between layers.
[0074] A set of pore pressure monitoring points was set up above and below the weakly permeable interlayer, and denoted as follows:
[0075] P1: 0.5m above the mezzanine
[0076] P2: Middle part of the interlayer
[0077] P3: 0.5m below the interlayer
[0078] 2. An elastoplastic dynamic constitutive model suitable for cyclic loading conditions is selected for the saturated sand layer to describe the stress-strain relationship and pore water pressure accumulation process of the saturated sand under dynamic loading.
[0079] The main parameters of saturated sand are as follows:
[0080] density
[0081] initial porosity
[0082] Initial effective stress
[0083] Volume compressibility
[0084] Permeability coefficient
[0085] The weakly permeable interlayer and the saturated sand adopt the same mechanical constitutive form. Except for the permeability coefficient, the other parameters of the weakly permeable interlayer are consistent with the sand layer. The permeability coefficient is taken as:
[0086]
[0087] This value is about 1600 times lower than the permeability coefficient of sand, which is used to create a significant seepage barrier effect.
[0088] 3. Apply gravity load to the model to generate an initial stress field, bringing the model to a state of static equilibrium. Set the groundwater level at the surface and ensure that the pore water pressure exhibits a linear static distribution along the depth direction.
[0089]
[0090] The upper part of the weakly permeable interlayer ( Taking (e.g.) as an example, its initial pore water pressure is:
[0091]
[0092] The average unit weight of the overlying soil layer is:
[0093] The total stress is then:
[0094] The initial effective stress is:
[0095] 4. The model employs a coupled analysis approach of dynamic response and pore water seepage, and its governing equations include:
[0096] Dynamic response control equations:
[0097]
[0098] Pore water seepage control equation:
[0099]
[0100]
[0101]
[0102] By setting a smaller in the weakly permeable interlayer Significantly reduces pore pressure dissipation flux in circulating dynamics
[0103] The increase in pore pressure of saturated sand under load can be expressed as:
[0104]
[0105] The first term represents the pore pressure increase caused by the compression of the skeleton volume; the second term represents the pore pressure increase caused by seepage and drainage.
[0106] Pore pressure dissipation, and the rate of pore pressure dissipation is proportional to the permeability coefficient:
[0107]
[0108] At the interlayer:
[0109]
[0110] That is, the pore pressure dissipation rate in the interlayer region is only 0.06% of that in the sand layer.
[0111] 5. Apply cyclic dynamic loads to the bottom of the model to simulate earthquake or shaking table loading conditions. The dynamic loads are in the form of equivalent sinusoidal stress.
[0112] At peak stress amplitude Pa, loading frequency Below, the volume caused by a single cycle should
[0113] The variable increment is approximated as follows:
[0114]
[0115] Corresponding single-pass orifice pressure increment:
[0116]
[0117] Number of loops Post-cumulative effect:
[0118]
[0119] However, since the pore pressure cannot be effectively dissipated, the cumulative amplification factor is taken as 8.5 (determined by the seepage time scale ratio).
[0120] Bore pressure increment at the end of dynamic loading:
[0121]
[0122] During dynamic loading, the increase in pore water pressure is mainly caused by stress cycling, and the total pore water pressure...
[0123] for:
[0124]
[0125] 6. Introduce pore pressure ratio as an evaluation index:
[0126]
[0127] Substituting the data, we get:
[0128] when At that time, the soil was in a strongly softened state, indicating that the weakly permeable interlayer significantly amplified the pore pressure accumulation.
[0129] Cumulative effect;
[0130] The results show that:
[0131] The effective stress in this region has significantly decreased, approaching the critical liquefaction state.
[0132] Dynamic loads generate periodic shear stress, causing the sand skeleton to rearrange and compress the pores;
[0133] The low permeability coefficient of the weakly permeable interlayer makes it difficult for pore water to drain out in a timely manner;
[0134] Pore pressure continues to accumulate near the interlayer, leading to a rapid decrease in effective stress;
[0135] This creates a high pore pressure zone with a pore pressure ratio close to 1;
[0136] As can be seen from this example, under the condition of the presence of a weakly permeable interlayer, saturated sand is more likely to form a high pore water pressure zone under the action of cyclic dynamic load, the pore pressure dissipation process is significantly delayed, and the risk of liquefaction is significantly increased.
[0137] In summary, this invention establishes a dynamic fluid-structure interaction analysis model for saturated sand and introduces the permeability difference of weakly permeable interlayers to achieve a systematic evaluation of the evolution process of pore water pressure in saturated sand. The method has clear physical meaning and a clear model structure, and is suitable for pore pressure analysis and liquefaction determination of foundations with weakly permeable interlayers under impact loads or cyclic loads.
[0138] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers, characterized in that, The steps are as follows: Step S1: Taking saturated sand with a weakly permeable interlayer as the research object, establish a layered model composed of saturated sand and weakly permeable interlayer, and divide the saturated sand and weakly permeable interlayer into grids according to the finite difference grid division principle. Step S2: Based on the liquefaction and deformation mechanism of saturated sand under dynamic loading, a dynamic constitutive model suitable for cyclic loading conditions is selected, and different permeability coefficient parameters are assigned to the saturated sand layer and the weakly permeable interlayer, respectively. Step S3: Under the action of gravity, apply the self-weight load to the dynamic constitutive model to generate the initial stress field of the dynamic constitutive model. Based on the groundwater level, establish the initial pore water pressure field. According to the initial pore water pressure field, make the dynamic constitutive model reach the static equilibrium state before dynamic loading. Step S4: Based on the finite difference theory, construct a dynamic fluid-structure interaction analysis model of the dynamic response control equation and the pore water seepage control equation of saturated sand, and solve the dynamic response and pore pressure evolution process of the soil simultaneously during the calculation process; Step S5: Select impact load and cyclic load as dynamic load input according to the research purpose, and simulate the pore water pressure response of saturated sand under different dynamic conditions. Step S6: Extract the pore water pressure and effective stress response results at different depths and locations during dynamic loading to obtain the evolution law of pore pressure with time and space. Step S7: By comparing the pore pressure development characteristics under different permeability coefficient conditions of weakly permeable interlayers, quantitatively assess the influence of the permeability of weakly permeable interlayers on the accumulation, dissipation and liquefaction response of saturated sand pore pressure, and form pore pressure assessment results.
2. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, The weakly permeable interlayer is a silt layer and a clay layer with a permeability coefficient significantly lower than that of the upper and lower saturated sand layers. The layered model is established in a two-dimensional spatial form, and the layered model is spatially layered to clarify the thickness, burial depth and spatial distribution relationship of each soil layer.
3. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, The dynamic constitutive model is an elastoplastic model applicable to cyclic loading conditions. The dynamic constitutive model describes the stress-strain relationship and the accumulation process of excess pore water pressure in saturated sand under stress cycle. It assigns a low permeability coefficient parameter to the weakly permeable interlayer, which forms a pore pressure transmission hindrance zone in the layered model.
4. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, The initial pore water pressure field adopts a hydrostatic pressure distribution form.
5. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, In the dynamic fluid-structure interaction analysis model, the weak permeability characteristics of the interlayer are reflected by the differentiated permeability coefficient parameters, and reasonable drainage boundary conditions are set.
6. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, The impact load is used to simulate explosion, pile driving and short-term high-dynamic conditions, the cyclic load is used to simulate earthquake and shaking table loading conditions, and the dynamic load is applied to the model base or side boundary in the form of stress time history or velocity time history.
7. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, The pore water pressure development curve and effective stress evolution path are extracted to determine the liquefaction process of saturated sand.
8. The method for assessing pore pressure in saturated sand based on the permeability of weakly permeable interlayers according to claim 1, characterized in that, The pore pressure development characteristics include the pore pressure development curve, pore pressure peak distribution, and dissipation rate.