Consolidation Stress Research Articles

Influence of Anisotropic Consolidation on the Instability of Loose Granular Soils Under Undrained and Drained Loading

Previous studies, mostly experimental, have reported conflicting observations on the effect of the initial anisotropic consolidation stress ratio (η<sub>0</sub>) on the stress ratio at the onset of instability (η<sub>f</sub>) for drained and undrained loading that involve static liquefaction. They indicate that as η<sub>0</sub> increases, η<sub>f</sub> could decrease, increase, or remain invariant, albeit without providing potential mechanistic factors. In this study, the anisotropic critical state theory (ACST) is used to investigate potential factors, including compressibility, state, and fabric anisotropy, that can explain the influence of η<sub>0</sub> on η<sub>f</sub> under undrained and drained loading. The assessments consider numerical simulations with the ACST-based SANISAND-F model, insights from SANISAND-F based instability criteria, the instability surface concept, and available experimental observations. Our findings show that compressibility and fabric anisotropy (and its evolution) are key factors in explaining the influence of η<sub>0</sub> on η<sub>f</sub>. In particular, the results show that if fabric evolution is not substantial, an increase in η<sub>0</sub> decreases η<sub>f</sub> for materials with significant compressibility, whereas the effect of η<sub>0</sub> in low compressibility materials is minimal. On the other hand, for materials that promote fabric evolution, the results suggest that the effect of fabric changes counteract compressibility effects, potentially increasing η<sub>f</sub>.

Effect of Drained Multi-Directional Loads on Liquefaction Resistance of Granular Material

ABSTRACT It is well recognized that the liquefaction resistance is closely related to the consolidation stress in soils. However, previous studies investigated the effects of unidirectional consolidation loads rather than multi-directional consolidation loads on liquefaction resistance. In this study, two types of granular materials, spherical glass beads and irregularly-shaped sands, are tested under undrained conditions with the uni- and bi-directional loads to investigate the liquefaction resistance. The effects of consolidation loads on liquefaction resistance can be explained in terms of material anisotropy. In simple shear tests, the stress- and strain-controlled loading paths are adopted for the consolidation and the undrained shear process, respectively. The results indicate that the liquefaction resistances of both materials consolidated under the multi-directional consolidation loads are higher than those consolidated under the linear loads. More consolidation loading cycles induce a better liquefaction resistance of the specimens at a given relative density. In addition, the influence of consolidation stress on liquefaction resistance is demonstrated by the anisotropy of specimens. Cyclic vertical stress, unidirectional shear stress, and bidirectional shear stress applied during consolidation produce greater isotropy and improve the liquefaction resistance of the specimen compared with the monotonic vertical stress, and their effects align with an increasing order.

Evaluation of empirical and machine learning models for predicting shear wave velocity of granular soils based on laboratory element tests

Shear wave velocity (Vs) is crucial for designing geotechnical systems subjected to dynamic loads, especially in seismically active regions. The shear wave velocity of geomaterials can be determined using in situ and laboratory tests. However, due to time and cost limitations, the Vs is not easily available in most projects. Various empirical models have been developed by researchers for predicting the shear wave velocity of geomaterials. However, most of these models have been developed for specific soil types and loading characteristics. In this work, for predicting the shear wave velocity of granular soils using various combinations of input parameters, various empirical models were proposed. Furthermore, machine learning (ML) methods were utilized to predict the Vs. The suggested models consider the impact of grading characteristics such as fine content (FC), gravel content (GC), median particle size (D50), uniformity coefficient (Cu), and coefficient of curvature (Cc), as well as void ratio (e), mean effective confining pressure (σm′), consolidation stress ratio (KC), and specimen preparation techniques for reconstitution of specimens. To achieve this, a series of bender element tests were performed on various sand and gravel mixtures. Furthermore, data from previous studies were also used. So, the study utilized 513 data points from laboratory element experiments conducted on granular soils. For predicting the Vs of granular soils, four empirical models and three ML models, namely Artificial Neural Network (ANN), Support Vector Regression (SVR), and Gradient Boosting Regression (GBR), were developed in this study. The findings showed that the ANN model outperforms the other comparative models in terms of accuracy and error. While the empirical models may serve as useful tools for initial Vs estimation in construction projects, the study primarily highlights the significance of using ML methods to enhance the prediction accuracy of Vs based on the available soil properties.

Laboratory tests on the traffic-induced cyclic behavior of anisotropically overconsolidated clay under different drainage conditions

In road engineering on clay foundation, the subgrade clay is often anisotropically overconsolidated, and the drainage boundary is commonly partially drained. Considering that few laboratory studies focused on the traffic-induced cyclic behaviors of anisotropically overconsolidated clay, and investigated intensively the differences in deformation between undrained and partially drained conditions, this study performs a series of one-way cyclic tests on the overconsolidated clay with various consolidation stress ratios (K) under different drainage conditions. The emphasis is put on the comparison of undrained and partially drained tests in terms of the permanent axial strain and its accumulated rate, resilient modulus and damping ratio. Test results indicate that the relative magnitude of permanent axial strain and its accumulated rate between the two drainage conditions is highly related to cycle number, K and CSR, with decreasing K and increasing CSR exacerbating the difference. The resilient modulus of partially drained tests is greater than that in undrained tests overall, while the relative relationship of degradation index between the two drainage conditions is reversed. In addition, the increase of consolidation-induced anisotropy degree promotes the strain development and improves the resilient stiffness, which should be noted for the traffic-induced deformation of subgrade clay. Based on the shakedown theory, the allowable cyclic stress ratio is determined as 0.44, and it is affected little by K or drainage condition. Finally, prediction models of permanent axial strain and resilient modulus are established for the anisotropically overconsolidated clay under both drainage conditions, where the deformation prediction is found to be related to the shakedown behavior. It is recommended that the prediction and control of subgrade clay settlement in engineering practice should take into account the in-situ consolidation sate and drainage condition.

Machine Learning Models for Predicting Shear Wave Velocity of Soils

As regards regions prone to seismic activity, shear wave velocity (Vs) is a design parameter for geotechnical systems exposed to dynamic loads. Evaluating Vs for geomaterials involves on-site and laboratory assessments; however, its availability is often limited in projects owing to resource and time constraints. Various mathematical and empirical models have been proposed to predict Vs for cohesive or granular soils; however, a majority of these models are specific to certain soil types and loading conditions. In this study, machine learning techniques were used for Vs prediction. These models encompass factors such as grading attributes, void ratio (e), mean effective confining pressure (σ’m), consolidation stress ratio (KC), and specimen preparation methods. To achieve this, a series of bender element tests was performed on various sand and gravel mixtures supplemented with culled data from earlier investigations. This study facilitated the development of three machine learning models aimed at predicting the Vs for granular soils: artificial neural networks (ANN), support vector regression (SVR), and gradient boosting regression (GBR), aimed at predicting Vs for granular soils. The findings of the study demonstrated that the ANN model exhibited enhanced precision and reduced error compared with the other models.

Predicting the shear modulus and damping ratio of soils using machine learning models

In geotechnical engineering, the accurate estimation of fundamental soil properties, such as the shear modulus ratio (G/G max) and damping ratio (D), is crucial to design and analyze various structures subjected to dynamic loads. This study presents a comprehensive investigation on harnessing the power of machine learning techniques to precisely predict G/G max and D of granular soils. Using an extensive dataset gathered from cyclic triaxial and resonant column tests on diverse mixtures of sand and gravel, combined with previous research findings, a series of advanced machine learning algorithms including shallow neural networks, support vector regression, gradient boosting regression, and deep feed forward neural network (DFFNN) were developed. The proposed models elucidate various influential parameters, including the grading characteristics, void ratio, confining pressure, consolidation stress ratio, and specimen preparation techniques. The superiority of the DFFNN model in terms of accuracy and predictive performance was demonstrated through rigorous evaluation and comparison. This study contributes to a better understanding of soil behavior under dynamic conditions. It also provides a robust framework to employ machine learning in predicting G/G max and D of granular soils, thereby enhancing the efficiency and reliability of geotechnical designs and construction practices.

Research on the rebound rule of a pit bottom caused by excavation of typical strata

In practical engineering, the magnitude of soil unloading rebound is closely related to the physical and mechanical properties of the soil. Therefore, there are significant differences in geological conditions among the different regions. As such, targeted research on the rebound law and calculation methods of foundation pits is needed. This article reports indoor experiments and numerical simulation methods which are used to study the trends and calculation methods of foundation pit rebound based on typical geological conditions in South China. Our findings are as follows. 1) At maximum consolidation stress ranging from 100 kPa to 400kPa, the maximum rebound rate of plain fill soil in typical soil layers is 0.0539–0.0704, the rebound rate of silty clay is 0.0373–0.0528, the rebound rate of coarse sand is 0.0296–0.0343, the rebound rate of gravelly cohesive soil is 0.0159–0.0305, the rebound rate of fully weathered granite is 0.0175–0.0344, and the rebound rate of strongly weathered granite is 0.0170–0.0379. 2) The rebound indices do not change with changes in the unloading ratio or initial consolidation stress. The rebound indices of the soil layer from top to bottom are 0.0143, 0.0119, 0.0077, 0.0096, 0.0083, and 0.0076, respectively, and a formula for calculating the rebound modulus of typical soil layers in South China was proposed. 3) The pore ratio of the soil after the end of the recompression process is lower than that which occurs after the first compression. The difference between the compression porosity ratio of the soil layer from top to bottom and the compression porosity ratio is 0.1, 0.08, 0.02, 0.06, 0.02, and 0.03, respectively. 4) The calculation of the depth of influence by the self-weight stress offset method is based on the theory of eliminating self-weight stress and unloading stress. The calculation depth is not affected by geological conditions, the formula for calculating the rebound modulus is consistent with the formula obtained from experimental research, and the calculation results are in good agreement with the numerical values.

Mechanical Characteristics of Tailings in Different Depositional Zones: A Case Study of Caijiagou Tailings Pond in Shaanxi, China

This study examines the widespread practice of upstream tailings dam construction in metallurgical mines in China, conducting comprehensive testing and research on tailings from various depositional zones of the Caijiagou tailings pond. Analysis of the test results from three types of tailings reveals a systematic relationship between the mechanical characteristics of tailings and their depositional zones: the farther from the dam, the finer the tailings particles, categorized as silty clay tailing, silt tailing, and sandy silt tailing. Consistent patterns were observed in the consolidated-drained shear strength and consolidated-undrained effective shear strength of these tailings. Among these, sandy silt tailing exhibited the highest strength, whereas silty clay tailing displayed the lowest. The dynamic stress–strain relationships of all three tailings types are described using the Hardin equivalent viscous-elastic model, where the initial dynamic shear modulus and the maximum dynamic shear stress in the model increased with effective confining pressure. The damping ratios exhibited a three-stage trend with increasing dynamic strain: gradual increase, rapid growth, and then gradual stabilization. Under various consolidated stress conditions, the ratio of the damping ratio to the maximum damping ratio versus the reduction in dynamic shear modulus showed a favorable linear relationship. Under vibration conditions, the dynamic shear stress corresponding to tailings failure increased with higher effective confining pressure and consolidated stress ratio. Finally, this study summarizes the parameters and indicators related to the saturated tailings of iron mines used in the research. Our work provides a foundation and reference for the design of tailings dams and the development and utilization of abandoned tailings ponds.

From sedimentation to consolidation of kaolinite: A molecular dynamic study

The consolidation of clay is the main measure for reclamation project, which is related to the compressibility, permeability, and coupling effect of clay-water. However, the mechanism of consolidation of clay remains unclear. This study focuses on the microscopic consolidation property of kaolinite using Molecular Dynamics (MD) simulation method. The nano-scale consolidation model was established to reproduce the sedimentation to consolidation. According to the different distribution of water film in pores, the consolidation process could be divided into different stages: (1) in the process of sedimentation and primary consolidation, the drainage occurred continuously except the strongly bound water; (2) just a part of the strongly bound water could be drained during the secondary consolidation. The minimum consolidation stress which can cause significant consolidation was found to be 0.1 GPa in a narrow throat of about 1 nm at nano-scale. The evolution of interparticle spacing between kaolinite particles during the consolidation process was analyzed to reflect the role of interparticle water on the pore water pressure and effective stress. Besides, models with different wettability show that the drainage of water on hydrophilic basal surface was difficult, while water molecules on hydrophobic basal surface are more easily expelled and have directional flow paths.

Acoustic monitoring of compaction in cohesive granular materials.

We study the transition from cohesive to noncohesive states of cemented granular materials (synthetic rocks) under oedometric loading, combining simultaneous measurements of ultrasound velocity and acoustic emission (AE: microseosmicity). Our samples are agglomerates made of glass beads bonded with a few percent of cement, either ductile or brittle. These cemented granular samples exhibit an inelastic compaction beyond certain axial stresses likely due to the formation of compaction bands, which is accompanied by a significant decrease of compressional wave velocity. Upon subsequent cyclic unloading-reloading with constant consolidation stress, we found the mechanical and acoustic responses like those in noncohesive granular materials, which can be interpreted within the effective medium theory based on the Digby's bonding model. Moreover, this model allows P-wave velocity measured at vanishing pressure to be interpreted as an indicator of the debonding on the scale of grain contact. During the inelastic compaction, stick-slip-like stress drops were observed in brittle cement-bonded granular samples accompanied by the instantaneous decrease of the P-wave velocity and AEs which display an Omori-like law for foreshocks, i.e., precursors. By contrast, mechanical responses of ductile cement-bonded granular samples are smooth (without visible stick-slip-like stress drops) and mostly aseismic. By applying a cyclic loading-unloading with increasing consolidation stress, we observed a Kaiser-like memory effect in the brittle cement-bonded sample in the weakly damaged state which tends to disappear when the bonds are mostly broken in the noncohesive granular state after large-amplitude loading. In this paper, we show that the macroscopic ductile and brittle behavior of cemented granular media is controlled by the local processes on the scale of the bonds between grains.

Mechanical properties of artificially structured soil and Binary-medium-based constitutive model under undrained conditions.

To investigate the mechanical properties and constitutive models of structured soil under undrained conditions, triaxial compression tests on initially anisotropic structured soil, isotropic structured soil, and remolded soil were conducted under consolidation undrained conditions at confining pressures of 25, 50, 100, and 200 kPa, respectively. The results demonstrate that the samples of structured soils with strong structural characteristics have an obvious yield strength when the consolidation stress is low. At this time, the pore water pressure in structured soils increases at the beginning of loading. As the axial strain increasing, it turns to reduce. When failure, the samples have obvious shear band. With the consolidation stress increases, the mechanical properties and deformation mechanism of structured soils are near to the remolded soil. Combining the Binary-medium theory with the analysis and discussion of the mechanical properties and deformation mechanisms of structured soil, the rationality of the corresponding Binary-medium model was verified, which shows that the constitutive model can reflect the characteristics of dilatancy and strain softening, volumetric contraction and strain hardening under the conditions of low and high confining pressure respectively. At the same time, the constitutive model can also reflect the differences in the stress-strain characteristics of the two structural soils caused by the structural differences. In general, the results agree with the experiment relative well.

Evaluation of Powder Flow Prediction by Ring Shear Testing at Low Consolidation Stresses

The development of XS-Lr0 low-stress shear cell by Dietmar Schulze (model RST-XS.s) has confirmed the necessity of assessing powder flow at low consolidation stresses for improved powder flow production (Søgaard et al.,2014). This project assessed different powder flow properties at low consolidation stresses via stress walk and discrete shear tests. Previous methodology by Sogaard et al, 2014 was investigated and further developed using different pharmaceutical materials at a wide range of consolidation stresses (0.25 – 4.00 kPa). A polynomial function best described the relationship between consolidation stress and unconfined yield strength, with results being material dependent. The lowest pre-consolidation stress observed for reliable measurements was 0.25 kPa. The findings emphasise the need to refine current methodologies to measure shear stresses at low consolidation stresses to improve powder flow prediction. 

Vacuum consolidation theory of dredged slurry considering nonlinear clogging behaviors

Clogging in the prefabricated vertical drains (PVDs) and soils is an inherent feature associated with vacuum treatment of slurry ground. The clogging column is characterized by nonlinear growth of volume over time and nonlinear permeability distribution along the radial direction. This study aims to develop a drain-well consolidation model for vacuum treatment of dredged slurry, with specific considerations of the nonlinear behaviors of the clogging column and PVD drainage capacity. The constitutive compression and permeation behaviors of the dredged slurry are described by extended power functions, which avoids the singularities associated with the conventional logarithmic constitutive equations when the effective consolidation stress approaches zero. Parametric studies were conducted to explore the consolidation effects while considering different combinations of parameters that govern the nonlinear behaviors of the clogging column and PVD-drainage capacity. The significance of considering the abovementioned nonlinear behaviors was demonstrated by comparing the field test results on a dredged slurry ground. Results indicate that clogging primarily affects consolidation by causing a nonlinear permeability distribution along the radial direction of the clogging column and nonlinear attenuation of PVD-drainage capacity.

Thermal and mechanical creep of clay in hypoplasticity

Clays and clay soils or shales have attracted a lot of interest in a variety of applications, including the development of geothermal resources [1], energy foundations [2], oil exploration [3], energy storage [4], and the storage of nuclear waste [5]. The continued operation of ground source heat pump installations can lead to considerable long-term settlements, which could negatively affect the adjacent or underlying foundations [1]. Therefore, thermal volume change has been widely experimentally investigated in clays [4, 7, 8, 9]. Especially in [4] the authors studied the thermal and mechanical consolidation of saturated marine clays through laboratory element tests, where excess pore pressures were generated by heating samples at constant water content and then allowed to dissipate. In constant stress creep experiments described in [4] it was documented that thermal creep strains typically increased linearly with log time at rates controlled by the prevailing temperature.
 On the other hand, the mechanical time dependency of the stress–strain behaviour of soft soils, especially highly plastic clay, is generally too significant to be ignored [10, 11]. The constitutive modelling of the time-dependent stress–strain behaviour of soils has been an active area of research for five decades and has attracted much attention from the international geotechnical community in recent years as denoted in [12]. In [13] a visco-hypoplastic (VHP) model for normally and overconsolidated clays has been proposed. Probably the most salient feature of hypoplasticity itself is that loading and unloading can be described with only one equation as with the strain and stress rate denoted as and , respectively. The elastic stiffness tensor is represented by ; is the degree of nonlinearity and is the flow rule (direction of hypoplastic strain). The last part of the equation expresses the time-dependent strain rate (i.e. viscous) with the material parameters as the viscosity index and being the compression index. denotes the overconsolidation ratio. As may be observed, the model is not restricted solely to time-dependent clay materials, because does not represent a singularity for the constitutive equation as in other hypoplastic models. The model has been extended in [14] to account for the small-strain stiffness and the mechanical behaviour under cyclic loading. It follows the critical state theory and incorporates a loading surface for the definition of , see Fig. 1A). Time-dependent one-dimensional behaviour of clays is in most cases explained by the isotache framework, which assumes a unique relation between effective stress, strain, and strain rate in compression, shown as loci of constant strain rate in space, see Fig. 1B). The creep deformation at constant effective stress (; Fig. 1C)) corresponds to a decrease in strain rate of the soil (path A to B in Fig. 1C)). Consolidation stress history, represented by swelling along the path AC, causes a marked reduction in compressive creep rates at low (CD), while expansive/dilative creep strains occur at higher (CEE).
 Due to the temperature dependency of the compressibility of clays the isotachs may be considered as temperature dependent as well. As shown in [6] the isotache loci at a given strain rate for normally consolidated states are functions of strain rate and temperature. Increases in temperature cause additional compressive thermal creep strains for NC and lightly OC states (BB and DD in Fig.1C)) and augment the swelling strains at higher (EE).
 In the framework of hypoplasticity, the non-isothermal behaviour has not gained much attention [15]. This work is devoted to the extension of the VHP model formulation to present a unified model for both thermal and viscous strains in clays. The model predictions are assessed through comparisons with existing laboratory experiments from [7] on two clays with measurements of both isothermal/mechanical creep and thermally induced creep strains, providing a thorough calibration scheme as well.

Triaxial tests on anisotropic consolidated methane hydrate-bearing clayey-silty sediments of the South China Sea

Comprehensive mechanical investigations must be undertaken for hydrate-bearing clayey-silty sediment to ensure their long-term suitability and safety. Affected by the earth pressure and stress history, the stress state of hydrate-bearing clayey-silty sediment typically presents anisotropic. In this study, 12 anisotropic consolidated shearing tests were conducted, the results show that stress-strain curves exhibit a strain-hardening trend and volumetric contraction for isotropic consolidated hydrate-bearing sediments at the typical saturation (∼30%) and pore porosity (∼45%). The internal friction angle is proportional to the consolidation stress ratio, while the cohesion is inversely proportional to consolidation stress ratio. The increasing consolidation stress ratio and effective confining pressure lead to an increasing failure strength, mainly due to the higher stresses causing a tighter alignment of soil particles, limiting the free motion of the particles and the extension of cracks. The presence of the initial axial stress leads to an interparticle locking in the soil skeleton.

Crushing and mechanical characteristics of coral sands under various stress paths

Coral sand is known to have stress path dependence and fragility. In this research, a series of drained triaxial tests were conducted to explore stress path effects on the mechanical and particle breakage characteristics of coral sands. Several mechanical characteristics, such as critical state, strength, and dilatancy characteristics were studied. The results revealed that the dilatancy behaviors, stress-strain responses, and crushing of coral sands were strongly affected by consolidation stress and stress path. The critical state lines of coral sands were straight in p‘-q space and e-(p‘/P a)0.44 plane regardless of stress path. Based on these characteristics, a dilatancy equation was derived and validated through test results. The developed dilatancy equation could predict the dilatancy relationships of coral sands under various stress paths.

Characteristics of MICP- and EICP-treated sands in simple shear conditions: a benchmarking with the critical state of untreated sand

Microbial- or enzyme-induced calcium carbonate (CaCO3) precipitation (MICP and EICP) are relatively new ground improvement techniques. In this study, the mechanical behaviour of biotreated (MICP/EICP) and untreated sands was investigated in light of the critical state soil mechanics framework using a series of direct simple shear (DSS) tests. A wide range of calcium carbonate content (CC), initial void ratio after consolidation (e0) and effective initial normal stress ([Formula: see text]) was considered. The biotreated specimens showed improved shear strength and dilative tendency compared to untreated specimens with similar initial states. The ultimate state (US) for the biotreated sand shifted towards a smaller void ratio (e) than the value of e at the critical state of untreated sand at the same σ′N in e–log σ′N space. Compared to untreated sand, a significantly larger US stress ratio was achieved for the biotreated sand, particularly at high CC and low [Formula: see text]. The characteristic features of undrained behaviour, such as instability stress ratio, stress ratio at phase transformation and flow potential showed good relationships with modified initial state parameter, void ratio after biotreatment and CC. The bonding ratio, (τ/σ′N)bond, was used to quantify the interparticle bonding. The peak value of (τ/σ′N)bond for the biotreated sand was significantly larger than zero, particularly at high CC and low [Formula: see text], while the peak (τ/σ′N)bond for the untreated sand was negligible. It was also observed that the mobilisation and degradation of calcium carbonate bonds in biotreated sand during DSS shearing are influenced by both CC and [Formula: see text].

Strength Model of Soda Residue Soil Considering Consolidation Stress and Structural Influence

Strength Model of Soda Residue Soil Considering Consolidation Stress and Structural Influence

Constitutive modeling of clay shales in undrained conditions and its experimental verification for Opalinus Clay

Clay shales are low-permeable sedimentary rocks that exhibit inherent cross-anisotropic stiffness, strength, and permeability. Accurate design of tunnels excavated in clay shales requires appropriate constitutive models that account for the anisotropic properties of the host rock, especially under undrained conditions. This paper presents a transversely isotropic elastoplastic-damage model for fully-saturated clay shales in undrained conditions. The model describes four deformation regimes observed during consolidated undrained experiments, i.e. (1) transversely isotropic elastic deformation, (2) anisotropic plastic deformation with cross-anisotropic peak strength, (3) semi-brittle post-peak softening due to both strength and stiffness degradation, and (4) residual strength state. The performance of the model was evaluated using available laboratory tests for Opalinus Clay, the selected host rock for underground disposal of radioactive waste in Switzerland. A large experimental data set, consisting of 18 undrained triaxial compression tests, was used to back-calculate the required model parameters. The adopted experimental data include the effective stress path and the stress–strain curves of specimens with bedding orientations between 0° and 90° with respect to the loading and effective consolidation stresses between 0.76 and 16 MPa. It is shown that the proposed model adequately captures the key material features of Opalinus Clay observed in the undrained experiments.

Study of Mechanical Properties of Saline Soils under Different Stress Paths

The stress path is a critical factor affecting the mechanical properties of saline soils. In order to study the mechanical properties of saline soils under different stress paths, in situ saline soils in the Qian’an area of western Jilin province were selected for this study, and triaxial shear tests under six different stress paths were conducted, including the consolidated undrained triaxial test under the conventional stress path under the isobaric consolidation condition; the consolidated drained triaxial test under the conventional, equal p, reduced p, and increased p stress paths under the isobaric consolidation condition; and the consolidated drained triaxial test under the conventional stress path under the K0 consolidation condition. The effects of the consolidation conditions, drainage conditions, and stress paths on the mechanical properties of in situ saline soils were investigated. The results reveal that the stress–strain relationship curves of soil samples decrease continuously in the order of increased p, conventional, equal p, and decreased p, and they all show the characteristics of strain hardening. The stress path curves have the same slope under the same stress path. For different confining pressures, only the relative positions of the curves are different. Under the conventional stress path, the slope is 1; under the increased p stress path, the slope is 1/3; under the equal p stress path, the slope is 3; and under the decreased p stress path, the slope of the curve is −1. For the same confining pressure, the magnitude relationships of shear strength under the different stress paths are as follows: increased p > conventional > equal p > decreased p. For the cohesion c and internal friction angle φ, the consolidation condition has a greater effect on the cohesion c and a smaller effect on the internal friction angle φ; the drainage condition has a smaller effect on the cohesion c and a larger effect on the internal friction angle φ; and the stress paths have a greater effect on both cohesion c and internal friction angle φ.