Saturated Sand Research Articles

A hydrogeophysical framework to assess infiltration during a simulated ecosystem-scale flooding experiment

This study presents a framework to quantify changes in soil saturation in response to flooding caused by extreme hydrologic perturbation on coastal ecosystems at the interfaces and transition between terrestrial and aquatic systems. Subsurface heterogeneity limits the use of in situ measurements to quantify subsurface flow during flooding due to the spatial discontinuity in the measured data. While geophysical methods, including time-lapse electrical resistivity imaging (ERI), are increasingly used to monitor soil hydrological processes, their abilities to parameterize flow models have been underutilized. This study combines background ERI, ground penetrating radar (GPR), time-lapse ERI, soil characterization, and a numerical flow model developed using an Advanced Terrestrial Simulator (ATS) code to quantify the infiltration pathway and describe the hydrological dynamics during a simulated flooding experiment. We assessed the use of two conceptual models developed using [1] ERI and GPR data that described the stratigraphic distribution, and time-lapse ERI that mapped permeability contrast, and [2] information from a national soil database for capturing changes in saturation. Combining the ERI and GPR results with soil core data revealed the stratigraphic heterogeneity at the site with a silty clay layer from 1 to 2 m between an overlying loamy topsoil and an underlying saturated silty sand. This silty clay layer could restrict deep infiltration. The time-lapse ERI showed up to a 35% decrease in resistivity, which correlated with soil moisture data (R2 value > 0.53) and revealed preferential infiltration zones used to inform the flow model. Numerical simulation results from both the geophysics- and soil database-informed models quantified changes in soil saturation with calculated soil moistures that agreed with field data. The geophysics-informed model captured more of the system’s variability, reflective of shallow subsurface heterogeneities. The framework presented will serve as a precursor for a robust ecohydrological model that can describe the impacts of extreme events induced by climate change on coastal ecosystems.

Designing, analyzing, and experimentally verifying a uniaxial shear box for investigating the length effect of buried pipelines during soil liquefaction

During an earthquake, buried pipelines can be threatened by various factors such as fault movement, ground motion, and soil liquefaction. Among these, fault movement and ground displacement have been identified as the most direct causes of pipeline fracture and rupture, as evidenced by previous earthquake disasters. While numerous studies have focused on the failure modes and mechanisms of pipelines crossing faults, little attention has been given to the dynamic uplift behavior of buried pipelines during soil liquefaction. To address such an issue, this study designed a uniaxial shear box to investigate the dynamic characteristics of buried pipelines during soil liquefaction. The box dimensions are 3600 mm × 1000 mm × 1100 mm and can embed a pipeline specimen of 3000 mm in length for testing. The seismic input motion direction is designed to be consistent with the axial direction of the pipeline to avoid lateral input motion influence. This study used DEEPSOIL analysis software to investigate whether the response of a uniaxial shear box under conditions of dry sand and saturated sand is consistent with theoretical analysis results. In addition, a preliminary test was conducted to ensure compliance with the requirements of subsequent pipeline tests, specifically on the uplift behavior of buried pipelines. The results showed that the soil dynamic responses under both dry sand and saturated sand conditions were consistent with the DEEPSOIL analysis software results. Furthermore, the pipeline test results verified that the input motion did not generate additional forces on the buried pipeline, but did indeed trigger soil liquefaction and cause the pipeline to uplift. These findings demonstrate that the uniaxial shear box designed in this study meets the design requirements and can be used to investigate the dynamic response of buried pipelines subjected to soil liquefaction under the influence of length effects in future studies.

Differential bleaching of quartz and feldspar luminescence signals under high-turbidity conditions

Abstract. Sediment burial dating using optically stimulated luminescence (OSL) is a well-established tool in geochronology. An important but often inapplicable requirement for its successful use is that the OSL signal is sufficiently reset prior to deposition. However, subaqueous bleaching conditions during fluvial transport are vastly understudied; for example the effect of turbidity and sediment mixing on luminescence bleaching rates is only poorly established. The possibility that slow bleaching rates may dominate under certain transport conditions led to the concept that OSL could be used to derive sediment transport histories. The feasibility of this concept is still to be demonstrated, and experimental set-ups are still to be tested. Our contribution to this scientific challenge involves subaquatic bleaching experiments, in which we suspend saturated coastal sand of Miocene age in a circular flume and illuminate it for discrete time intervals with natural light. We record the in situ energy flux density received by the suspended grains in the UV-NIR frequency range by using a broadband spectrometer with a submersible probe. Our analysis includes pre-profiling of each sample following a polymineral multiple signal (PMS) protocol. Using the PMS, the quartz-dominated, blue-stimulated luminescence signal at 125 ∘C (BSL-125) decays slower than the K-feldspar-dominated, infrared-stimulated luminescence signal at 25 ∘C (IR-25) even under subaerial conditions. The BSL-125 from purified quartz shows the opposite behaviour, which renders the PMS unreliable in our case. We find a negative correlation between suspended-sediment concentration and bleaching rate for all the measured signals. For outdoor bleaching experiments we propose to relate the measured luminescence dose to the cumulative received irradiance rather than to the bleaching time. Increases in the sediment concentration lead to a stronger attenuation of the UV–blue compared to the red–NIR wavelength. This attenuation thereby follows an exponential decay that is controlled by the sediment concentration and a wavelength-dependent decay constant, λ. As such λ could potentially be used in numerical models of luminescence signal resetting in turbid suspensions.

Assessment of accumulated lateral displacement of a flexible pile due to cyclic lateral loads in saturated sand

Pile foundations, which support offshore structures, are primarily subjected to cyclic lateral loads. The accumulated lateral displacement of the pile foundation is a critical parameter that affects the overall stability of the structure. This study presents a series of cyclic lateral loading tests conducted on flexible model piles installed in saturated sand with varying relative densities and cyclic loading characteristics. Based on the experimental results, a model is proposed to predict the accumulated lateral displacement of a pile under cyclic lateral loads. The proposed model takes into account the number of load cycles and the cyclic load ratio (the ratio of the minimum to maximum cyclic load) and is validated using experimental data. The results show that the accumulated lateral displacement increases exponentially with the number of load cycles and is influenced by the cyclic load ratio and the relative density of the sand. The proposed model provides an accurate prediction of the accumulated lateral displacement of piles installed in saturated sand and can be used to design pile foundations for offshore structures.

A simplified procedure for the prediction of liquefaction‐induced settlement of offshore wind turbines supported by suction caisson foundation based on effective stress analyses and an ML‐based group method of data handling

AbstractIn this research, a series of non‐linear dynamic finite element (FE) effective stress analyses were conducted to analyze the influence of the suction caisson geometry, ground motion intensity and contact pressure caused by the offshore wind turbine (OWT) on the settlement pattern and seismic demand of the OWT's structure on saturated dense sand. The baseline model and the FE procedure were validated using a database of well‐documented centrifuge tests. However, particular attention was given to the calibration campaign based on the measured system response quantities, such as the settlement, acceleration and pore‐pressure time histories. The FE results identified the contact pressure as an important state parameter caused by the OWT's mass; the governing ground‐shaking intensity measures that play a significant role in the derivation of an analytical framework for predicting liquefaction‐induced OWT settlements during major events are the shaking intensity rate (SIR), Arias Intensity ( and spectral acceleration at a period equal to 1 s (T = 1 s). The results revealed that approximating expressions derived using the modified least‐squares method (MLSM) reasonably capture the complex phenomenon of liquefaction‐induced settlement, with some exceptions at lower SIR values. Finally, to obtain the approximating expressions, the database was combined with a machine learning (ML)‐based group method of data handling (GMDH) that appropriately describes the interplay of multiple properties of the foundation soil, structure and seismic events while incorporating the effect of the interaction between the suction caisson, foundation soil, excess pore‐pressure generation and cyclic shear stresses.

Influence of X-Ray beam exposure on the development of gas bubbles during triaxial testing of sand using 3D synchrotron micro-computed tomography

The constitutive behavior of granular materials is highly influenced by the degree of saturation and whether a saturated or unsaturated framework is adopted to model the behavior of granular materials. Conventional axisymmetric triaxial compression (CTC) testing of saturated specimens tends to assume that the specimen remains saturated during shearing. X-ray computed tomography (CT) has allowed for 3D in-situ measurements beyond the global scale to investigate microscale and localized events such as fabric evolution. The literature reported several CT-coupled geotechnical experiments of saturated specimens; however, no study examined how X-ray exposure might affect the specimen, specifically the radiolysis of pore water. In this study, we present the synchrotron micro-computed tomography (SMT) results of experiments performed on sand specimens without shearing (acrylic tubes) and with shearing (CTC experiments) to assess the influence of X-ray exposure on the development of the gas phase of saturated sand. The observed phase changes were dependent on the initial pore water pressure and duration of exposure to the X-ray; the behavior of individual gas bubbles was dependent on the bubble’s surrounding sand grains and pore throat sizes leading to changes in the degree of saturation.

Laboratory Study of Grouting Method to Improve Loose Sand Against Liquefaction

Liquefaction is a phenomenon when soil behaves like liquid during earthquake, and only occurs in saturated loose fine sand with grain size ranging from 0.2 to 0.02 mm. Liquefaction can be devastating, causing failure and deformation to buildings, roads, and bridges. Thus, research study on the application of grouting method for improving liquefiable fine sand in the laboratory is carried out. Grouting is a soil improvement method that injects cementing agent into a soil mass. After the grout has solidified, the soil density and consistency of the soil will improve. This research proves, mathematically and experimentally, that grouting can improve the density and consistency of liquefiable sand, thus reducing the liquefaction potential. Grouting liquefiable saturated sand basically compacts the soil, leading to consolidation as soil pore-water is dissipated during the grouting process. It is found that the volume of grout per unit volume of soil mass treated is directly proportional with the reduction of void ratio and increase in soil density.

Experimental study on mass transfer behavior and mechanism in nuclide-containing sandy soil under temperature gradient

The level of nuclear waste emergency disposal is an important factor restricting the rapid development of the nuclear energy industry under the trend of global energy revolution. To promote the effective application of artificial ground freezing (AGF) for the treatment of nuclear wastewater leakage, the mass transfer and migration mechanism of key nuclides (137Cs, 90Sr, and 129I) during unidirectional freezing of saturated silty sand were elucidated in this study. Temperature sensors and a nuclear magnetic resonance (NMR) were used to explore the internal temperature and moisture variation characteristics of nuclide-containing sandy soil during the freezing. Furthermore, using the designed device, a unidirectional freezing of different nuclide-containing sandy soils was performed to establish a relationship between the development characteristics of the freezing front and the mass transfer of nuclide. The results show that the T2 spectrum of nuclide-containing sandy soils has the most significant change from 0 °C to -1 °C, and the bound water content of I-containing sandy soil remains evident change when the temperature decreases below -1 °C. During unidirectional freezing, owing to the influence of the freezing front on nuclide migration, the resistivity curve exhibits a V-shaped jump, and the concentration peaks appear in turn along the freezing direction and show a stepwise increase. Nuclide mobility is closely related to the freezing rate of the corresponding location. With an increase in freezing thickness, the freezing rate decreases and the nuclide mobility increases. Owing to the combined influence of water-ice phase transition, concentration gradient and matrix suction in sandy soil, the concentration only increases within a small area at the face of the freezing front. The differences in migration behavior of nuclides in sandy soil driven by temperature gradient is mainly due to the different degrees of compression of nuclide ion on the diffusion double electric layer of soil particles, which results in different forms of unfrozen water within the sandy soils. The overall mobility of the three nuclides shows the following sequence: Cs>I>Sr. In the practical application of AGF, attention should be paid to the effects caused by the rapid migration of low-valence cationic nuclides and the retention of high valence cationic nuclides in the frozen wall.

Uniplanar multirod TDR probe for soil water content measurement over a larger spatial scale

AbstractThis study developed a uniplanar multirod time domain reflectometry (TDR) probe and evaluated it in laboratory experiments for soil water measurement over a larger spatial scale. The sampling volume of the probe was determined by simulating the electric potential distribution around the probe rods by using the HYDRUS‐2D software package and verified by comparison with the measured dielectric constant in saturated sand. The performance of the probe was evaluated by comparing its dielectric measurements in wet sand over a wide range of water content during evaporative drying with that measured by CS640 probes. Additionally, the dependency of visible light reflection on the water content of the sand was evaluated. The results revealed that the average effective thickness of the probe's sampling volume was 5–6 cm on both sides of the plane of the probe rods. The probe accurately measured the soil water content over a 0.88 m2 spatial area. The visible light reflectance of the variably saturated sand surface and the corresponding water content of the sand follow a soil water retention function‐type relationship. The usage of the multirod TDR measurement system at a larger spatial scale carries practical implications, especially in increasing the accuracy of remote sensing data.

Experimental evaluation of the pull-out behavior of suction caissons in saturated sand soil

This paper presents an experimental and analytical investigation of the extraction behavior of suction caissons in saturated sand. The extraction of suction caissons was performed at four different pullout rates (i.e., 1 mm/s, 3 mm/s, 8 mm/s, and 23 mm/s), three different pullout angles (i.e., 0°, 30°, and 45°), and two different suction caisson heights (i.e., 100 mm and 150 mm). Furthermore, a formula has been derived to calculate peak loads achieved from the experiments based on the pullout rate and angle. The results indicate that the extraction behavior of suction caissons is significantly impacted by the pullout rate and pullout angle. The pullout capacity of suction caissons with varying heights can be increased by both increasing the pullout rate or decreasing the pullout angle. When testing the 100 mm diameter caisson, it was discovered that by increasing the pull-out rate by 23 times while keeping the same conditions, a remarkable 115% increase in pull-out resistance was achieved. Additionally, a notable 83% increase in pullout resistance was observed by reducing the pullout angle from 45° to 0° under the same conditions. The findings from the equation presented in this study are compatible with the experimental results.

Three-dimensional finite element analysis of the effect of soil liquefaction on the seismic response of a single pile

Soil liquefaction is considered as one of the most significant issues that leads to failure of shallow and deep foundations. However, the effect of liquefaction on the seismic response of piles still poorly understood. Therefore, this research examines the seismic response of a pile embedded in soil stratum of saturated fine-grained soils. Midas GTS/NX is used to carry out the number assessment. In addition, the modified UBCSAND soil constitutive model is used to depict the nonlinear features of saturated sand during earthquake waves. The developed three-dimensional model is first validated using the results of a shaking table test of a pile embedded in coarse-grained soil, where good agreement is obtained between the finite element model and the experimental results for the displacement, acceleration, and liquefaction ratio demonstrated good agreement. Furthermore, the orientations of the vectors produced by the numerical study, that matched a global circular flow characteristic, reflected the movement of the liquefied soil all around pile. The findings showed a considerable decrease in the pile frictional resistance during the seismic events as a consequence of increasing the pore water pressure and subsequent liquefaction. Regarding this, before the soil was entirely softened, resistance due to friction was observed near the ground, in correspondence with the loose sand layer. In addition, the pile showed excessive settling, which is due to the decrease of the soil stiffness caused by the increase of the pore water pressure. The results of this research provide an insight into the mechanism of the behavior of pile in saturated coarse-grained soils and thus, it helps to improve future research on the topic and also achieve better design of piles embedded in saturated coarse-grained soils.

Effects of consolidation conditions on the dynamic shear modulus of saturated coral sand over a wide strain range

The utilization of coral sand as a construction material for ports and other infrastructure systems in coral reefs is prevalent, wherein the soil elements within slopes and embankments typically experience an anisotropic stress state. It is imperative to accurately characterize the degradation behavior of the stratigraphic material's stiffness across a wide range of strains. In this study, the maximum and strain-dependent shear modulus (G0 and G) characteristics of saturated coral sand under isotropic and anisotropic consolidations were investigated by performing multi-stage stress-controlled undrained cyclic torsional shear tests with cyclic hollow cylinder shear apparatus. The experimental results indicated that G0 and G generally rose with increasing initial effective consolidation pressure but decreased with increasing inclination of initial major principal stress from the vertical (αc). In contrast, the effect of consolidation stress ratio (kc) on G0 and G was nonmonotonic, and that of kc and αc on the strain-dependent shear modulus reduction (G/G0) curve was slight. By defining anisotropic consolidation indexes δ0 and δr used for quantifying the effect of consolidation-induced anisotropy on the G0 and the G/G0, respectively. A unified formula of G0 obtained by multiplying Hardin's model by δ0, as well as a unique formula of G/G0 obtained by correcting γr in the Davidenkov skeleton curve expression as a linear function of δr were established under various consolidation conditions, respectively. The proposed G formula over a wide strain range is well validated by the experimental data for siliceous sandy soils from the literature.

A numerical approach for simulation of stress-controlled cyclic shear loading in a soil column considering partial drainage

Liquefaction strength curves (LSCs) are commonly generated based on undrained stress-controlled cyclic testing to define the liquefaction potential of sands. However, these LSCs do not consider the effect of partial drainage on liquefaction potential. This is mainly because there are very limited experimental techniques to run stress-controlled tests for partially drained sands. This manuscript proposes a procedure to numerically simulate a saturated sand column with a free drainage boundary at the top (or top and bottom), accelerated horizontally at the bottom with constant acceleration cycles of duration designed to generate constant cyclic shear stress histories in the column. This is done for columns subjected to low and high overburden pressures. The paper starts with numerical simulations of a typical undrained cyclic direct simple shear, CDSS tests by applying a stepped velocity wave to a single soil element, an already established approach. This approach only works for a single element in undrained condition which is fixed at the base. Then, the proposed procedure is implemented by applying stepped acceleration time histories at the base of soil columns having one or two drainage boundaries. In these stepped acceleration runs, the durations of the acceleration cycles are controlled to achieve a partially drained stress-controlled CDSS kind-of-loading at specific elevations within the soil columns. The technique is used to show the effect of partial drainage on sand liquefaction behavior at both low and high overburden pressures. The results show that the effect of drainage is much more significant at higher overburden. The existence of both top and bottom drainage boundaries resulted in less liquefaction vulnerability, as compared to having only one drainage boundary at the top of the sand column. The results show that liquefiable sand layers in the field may be less prone to liquefaction under high overburden pressure than predicted by the current state-of-practice, which relies mainly on undrained small-scale cyclic tests.

SHRINKAGE MITIGATING STRATEGIES ON HIGH-PERFORMANCE SELF-CONSOLIDATING CONCRETE (HP-SCC)

Cracking in high-performance self-consolidating concrete (HP-SCC) is a significant concern that must be addressed during design and construction. HP-SCC is a concrete type reinforced with high-strength fibers, such as steel or synthetic fibers, to enhance its mechanical properties. HP-SCC is known for its high flowability and ability to self-consolidate without vibration, exceptional strength, durability, and crack resistance compared to conventional concrete. HP-SCC is highly durable and can withstand various environmental conditions and aggressive exposures. Combining high-strength fibers and advanced cementitious materials in HP-SCC improves resistance to chemical attacks, freeze-thaw cycles, abrasion, and impact. Utilizing an expansive agent (EA), shrinkage-reducing admixture (SRA), and saturated lightweight sand (LWS) ensures HP-SCC with a low risk of cracking. This study investigates using different types of EAs to improve compressive and flexural properties. Furthermore, the study investigates the combination of fiber, EA, and LWS in promoting high resistance to autogenous and total shrinkage. The dense microstructure of HP-SCC also contributes to its durability by reducing permeability and minimizing the ingress of moisture and harmful substances.

Saturated Fluid Variation Effect on Seismic Anisotropy: A Case Study of Deep-Water Reservoir

Many factors can drive seismic anisotropy, whether it is the intrinsic condition of rock, external force, or longwave anisotropy. Saturated fluid, as one of the reservoir’s intrinsic elements, is known to trigger an anisotropic effect in far offset seismic with Vertical Transverse Isotropic character. Anisotropy on seismic presents as hockey stick curving that a combination of two-parameter could correct during move-out: V NMO and the elliptical anisotropy η parameter. This research means observing how the saturated fluid within the reservoir contributes to the observed anisotropy in seismic. Rock physics modelling (RPM) and fluid substitution (FRM) are conducted to investigate the saturated fluid effect at a particular temperature and pressure that reflects the deep-water environment. The anisotropy parameter is extracted by applying Tsvankin 4th Order NMO to obtain the elliptical anisotropy η parameter. Based on synthetic seismic modelling with VTI Rüger Reflectivity, saturated fluid has an effect on far offset seismic as a manifestation of seismic anisotropy η. In this case of a deep-water environment, gas saturated sand needs the most considerable η correction, followed by oil and water-saturated. Although the η value difference is relatively small and easily dismissed as insignificant, saturated fluid indeed does contribute to the observed seismic anisotropy.

Shaking table test on underwater slope failure induced by liquefaction

Sand liquefaction is a process in which the excess pore water pressure of saturated sand soils increases and the effective stress of saturated sand decreases under the action of vibration, resulting in the transition of sand soils from the solid state to the liquid state. In this paper, an underwater sand slope model containing the upper sand slope and the bottom non-liquefied clay layer was designed. The whole process of large deformation of flow liquefaction from the solid state to the liquid state was reproduced by the shaking table test and recorded by the high-definition particle image velocimetry (PIV) equipment. Four main influencing factors: the acceleration amplitude of the shaking table, the frequency of the shaking table, the relative density of the sand slope, and the slope ratio of height and width of the sand slope, were considered. During the test, the dynamic response characteristics of acceleration and excess pore water pressure (EPWP) within the underwater sand slope model were monitored and analyzed in the whole deformation process to reveal the mechanism of the sand liquefaction process and the law of development and provide data support for subsequent research.

Effect of cyclic loading frequency on cyclic behaviour of saturated sand

In practical engineering, sand fill or sediments subjected to cyclic loadings at varying frequencies due to earthquakes, traffic, and waves may cause complex soil responses. To investigate the effect of loading frequency on the cyclic behaviour of saturated sand, a series of undrained cyclic torsional shear tests covering a wide range of loading frequencies were conducted on Fujian sand. The excess pore water pressure (EPWP) in saturated sand can be divided into two components: residual and transient. Special focus was on the effect of loading frequency on the development of residual EPWP, transient EPWP, and shear strain amplitude. The key finding demonstrates that the loading frequency has a considerable effect on the association between the double amplitude of transient EPWP and shear strain amplitude. Based on the test data, a threshold strain is proposed that can be used to predict the onset of shear dilatancy in saturated sand. The liquefaction strength in the cyclic torsional shear tests was also investigated and was found to be significantly influenced by the loading frequency. The cyclic resistance ratio (CRR15) of saturated sand shows an increasing trend with the increase in loading frequency.

Research on dynamic p-y curves in liquefied sand under cyclic loading conditions

Under dynamic cyclic loads, the pore water pressure in saturated sand rises continuously, which leads to the reduction of horizontal bearing capacity or the damage of the pile foundation. Under dynamic cyclic loads, the existing calculations methods of horizontal bearing capacity of pile foundations were obtained by proposing a reduction factor for the static p-y curve model mostly. Compared with the test results, the soil resistance around the pile obtained by this method is often overvalued and the pile-soil relative displacement has a relative underestimation. As a result, this method is not suitable for pile foundation design. Therefore, the variations of soil resistance around the pile and the pile-soil relative displacement are obtained by analyzing the effect of pore pressure ratio on soil strength around the pile in saturated sand in this paper. The theoretical formulas related to the cyclic vibration times and pore pressure ratio are proposed. The proposed formulas are introduced into the dynamic p-y curve model to obtain the dynamic p-y backbone curve in the process of sand liquefaction. The research results show that the variations of the soil resistance around the pile and the pile-soil relative displacement are related to the pore pressure ratio and the cyclic vibration times during the sand liquefaction. As the cyclic vibration times increases, the pore pressure increases, the soil resistance around the pile decreases and the pile-soil relative displacement increases.

Dynamic monitoring of saturation profiles during two phase immiscible displacements in confined sand packs using time-domain analysis of the frequency domain electromagnetic sweeps

Water saturation 1D spatial profiles were monitored using real-time domain analysis of the measured frequency domain complex reflection coefficients of electromagnetic sweeps during oil and deionized water flood experiments at ambient conditions. Gravity and viscous induced fingering and piston-like displacement scenarios were explored. A patented coaxial transmission line core holder was designed to host saturated sand packs compressed in their axial and radial dimensions. An inverse chirp z-transform algorithm was used to convert the measured responses from frequency to time domain. An optimization routine was developed to convert the resulting time domain step responses to water saturation profiles at every pore volume fraction of fluids injected. Advancing and trailing fronts and their breakthrough times were detected. Darcy's flow analysis was performed to extract 1D pressure distribution spatial profiles and dynamic capillary pressure curves for 3 drainage floods. The oil ganglia flow and gravity fluid separation were detected in water floods.

Study on dynamic strength and liquefaction mechanism of silt soil in Castor earthquake prone areas under different consolidation ratios

Under the Castor earthquake, there is a risk of liquefaction instability of saturated tailings, and the evolution of dynamic pore pressure can indirectly reflect its instability process. Before applying dynamic loads, the static stress state of soil is one of the main factors affecting the development of soil dynamic strength and dynamic pore pressure, and there are significant differences in soil dynamic strength under different consolidation ratios. This paper conducted dynamic triaxial tests on saturated tailings silt with different consolidation ratios, and analyzed the dynamic strength variation and liquefaction mechanism of the samples using the discrete element method (PFC3D). The results showed that 1) as the Kc′ gradually increased, and there was a critical consolidation ratio Kc′ during the development of the dynamic strength of the sample. The specific value of Kc′ was related to the properties and stress state of saturated sand. The Kc′ in this research was about 1.9. When Kc < 1.9, dynamic strength was increased with the increase in Kc; when Kc > 1.9, dynamic strength was decreased with the Kc. 2) Under the impact of cyclic load, when samples were normally consolidated (Kc =1), the pore water pressure would tend to be equal to the confining pressure to cause soil liquefaction. In the case of eccentric consolidation (Kc > 1), the pore water pressure would be less than the confining pressure, thus, the soil liquefaction would not be induced, and the pore pressure value would decrease with the increase of consolidation ratio. This paper provides engineering guidance value for the study of dynamic strength and liquefaction mechanism of tailings sand and silt in Castor earthquake prone areas under different consolidation ratios.