Soil Behavior Research Articles

A novel tool for probabilistic modeling of liquefaction behavior in alluvial soil

ABSTRACT This research introduces and validates advanced machine learning models designed to predict the probability of liquefaction failure (pf) in alluvial soil deposits. Three optimisation algorithms namely Northern Goshawk Optimization (NGO), Jellyfish Search Optimizer (JSO), and Horse Herd Optimization Algorithm (HHO) coupled with Adaptive Neuro Fuzzy inference system (AFS) has been employed in the present research. Among the models tested, the AFS-HHO model exhibited superior predictive ability, with R2 = 0.93 and RMSE = 0.06 during the learning stage, and R2 = 0.89 and RMSE = 0.07 during the testing stage. This highlights the AFS-HHO model's efficiency in accurately predicting pf using only corrected SPT-N value i.e. (N1)60 and cyclic stress ratio (CSR). The study also emphasises the importance of the (N1)60 value in influencing the probabilistic assessment of liquefaction failure, and proposes a novel liquefaction probability assessment chart as a novel and reliable tool for estimating liquefaction failure of alluvial soil deposits. Considering the overall analysis, the proposed models offer a novel tool for geotechnical engineers to estimate the probability of liquefaction failure thereby holding substantial implications in the field of probabilistic evaluation in liquefaction studies.

EXPERIMENTAL EVALUATION OF EXPANSIVE SOIL STABILIZED WITH WHEAT HUSK ASH AND SISAL FIBER

Everything starts with soil. Being a civil engineer, we are aware of how essential soil is to construction, as everything is dependent on it. Before building any kind of structure on top of soil, we examine the soil's characteristics and behavior to determine its strength and ability to support the weight of the structure to be built on top of it. In this study work, we used agricultural waste materials, such as wheat husk ash (WHA), as a stabilized material in soil at different percentages of 5%, 10%, and 15% to perform various tests on the soil to determine its qualities or strength. Sisal fibers are inexpensive, readily available locally, and environmentally benign, making them an excellent choice for enhancing soil properties. The stabilizing effect of sisal fiber on soil characteristics has been experimentally investigated in this work. In light of this, an experimental study is carried out using pricey, locally accessible soil that has been blended with various percentages of sisal fiber. In the CBR mold and UCS sampler, soil samples are prepared at their maximum dry density (MDD) matching to their optimum moisture content (OMC) both with and without Sisal Fiber and WHA. In the laboratory, CBR and UCS tests are carried out in accordance with the proportion of Sisal Fiber by dry weight of soil, which is determined to be 1%, 1.5%, or 2%. According to test results, the amount of sisal fiber in the soil increases with its saturated CBR and UCS value. When wheat husk ash and sisal fiber are added, the CBR of the mix increases and the pavement thickness decreases, resulting in lower construction costs and ultimately, more economical highway building. Key Words: Compaction test, CBR, UCS, WHA, Sisal Fiber

Experimental study on deformation characteristics of seasonal subgrade soil under dynamic load.

In Northwest China, the highway infrastructure often faces challenges due to the widespread presence of subgrade soil. This soil undergoes significant changes in performance under cyclic loading and freeze-thaw cycles. To effectively design and construct highways in these regions, it is crucial to understand the impact of various factors on the deformation characteristics and mechanical properties of subgrade soil. This study aims to investigate the influence of freeze-thaw cycles, water content, confining pressure, and loading rate on the deformation behavior and mechanical properties of subgrade soil under cyclic loading conditions. Experimental tests were conducted to analyze the deformation characteristics and mechanical properties of the subgrade soil. The test results revealed the following: 1) Dynamic loading leads to a noticeable decrease in the strength of subgrade soil, resulting in a softening effect on the stress-strain curve. The cumulative strain of the soil is positively correlated with the number of freeze-thaw cycles and water content, while negatively correlated with confining pressure. The final cumulative strain remains below 1%. 2) The failure stress of subgrade soil decreases exponentially with an increase in freeze-thaw cycles, dropping from 224.52 kPa to 196.76 kPa. 3) An increase in water content linearly decreases the failure stress of subgrade soil, ranging from 377.1 kPa to 151.5 kPa. 4) Confining pressure exhibits a linearly increasing relationship with the failure stress of subgrade soil, ranging from 151.6 kPa to 274.5 kPa. 5) The failure stress of subgrade soil demonstrates a linear increase with the loading rate, ranging from 200.46 kPa to 210.62 kPa. These findings provide valuable insights for the design and construction of highways in seasonal frozen areas. They also offer guidance for preventing and mitigating subgrade freeze-thaw issues in the future.

Mechanical behavior of unsaturated soils from suction controlled ring shear tests

The shear strength behavior associated with a large shear deformation of both the fine- and coarse-grained unsaturated soils is important in interpreting and forecasting the initiation and movement of landslides. For this reason, a suction-controlled ring shear apparatus was designed by introducing modifications to the conventional Bromhead ring apparatus extending the axis translation technique. A series of suction-controlled ring shear tests were performed on fine- and coarse-grained unsaturated soil specimens subjecting to large shear deformation. The experimental results are presented and interpreted for highlighting: (i) the shear stress/void ratio-shear displacement relationships; (ii) the envelopes of the residual shear strength; (iii) the void ratio, water ratio and degree of saturation of the fine-grained soil specimens sheared to the residual state under different net normal stresses and matric suctions. These results provide valuable information toward understanding and interpreting the behaviors of landslides in unsaturated soils that experience the first failure and the reactivation along a pre-sheared slip surface.

Long-term agricultural reuse of treated wastewater and sewage sludge: developing a Time to Critical Content Index for metal species

This study evaluates the sustainability of spreading wastewater or sewage sludge on agricultural land, balancing benefits with contamination risks. Conventional ecological risk indices often fail to address the long-term accumulation of metals in soils. We investigate the feasibility of spreading based on current knowledge of potentially contaminating metals and their behavior in soil. We analyzed the speciation of metals (Ag, Cd, Co, Cr, Cu, Ni, Pb, Ti, Zn) through sequential extraction in sludge, treated wastewater, and soils after 14 years of application of sewage sludge and treated wastewater issued from an Algerian wastewater treatment plant. We introduce a Time to Critical Content Index (TCCI) that calculates the time required to reach critical levels of potentially mobile metals, considering total metal content and speciation. The TCCI takes into account product knowledge, soil characteristics, metal behavior, ecological/toxicological thresholds, and regulations. Applied to our case study, the TCCI indicates that spreading sewage sludge can continue despite metal contents exceeding regulatory ceiling values. The index serves as a precautionary measure, adaptable to evolving knowledge, providing a comprehensive framework for sustainable agricultural practices.Graphical

Relationships among fall cone flow index and consistency identifiers of fine-grained soils with emphasis on toughness limit

It is well known that plasticity characteristics are one of the most important factors controlling the engineering behavior of fine-grained soils. In this regard, Atterberg limits are used for evaluation of plasticity and strength behavior of soils. Of all the plasticity identifiers, fall cone flow index, which is the slope of the flow curve is a descriptor of plasticity and undrained shear strength characteristics of cohesive soils. On the other hand, toughness limit is also efficient in prediction of many index properties of soils including plasticity characteristics, compression index as well as residual friction angle. This study is an attempt to establish relationships among fall cone flow index and consistency identifiers of fine-grained soils. Emphasis is given on toughness limit, which is believed to be a practical and efficient approach in assessment of fall cone flow index. Regression-based equations establishing relationships between fall cone flow index, plasticity index, plasticity ratio, toughness limit and liquid limit were presented. Besides, the efficiency of artificial neural networks in prediction of toughness limit and fall cone flow index was investigated. It should be noted that established relationships using regression equations are based on regional data, which come up with coefficient of determination (R2) values ranging between 0.706 and 0.978. On the other hand, ANN models were used to model global data, R2 values were obtained to be between 0.586-0.972 and 0.522-0.889 for training and testing phases, respectively. Relationships concerning local and global data were presented, along with analysis of effectiveness of application of relationships established for analysis of global data.

Experimental study on the behavior of sandy soil reinforced by stone columns

Experimental study on the behavior of sandy soil reinforced by stone columns

Ameliorating the response of slow-releasing nitrogen fertilizer on sustainable maize growth

The extensive utilization of nitrogen (N) fertilizers within maize cultivation systems has resulted in diminished nitrogen use efficiency (NUE) and contributed to nitrogen pollution on a global scale. To assess the ecological repercussions of excessive fertilization, it is imperative to elucidate both the nitrogen use efficiency and the fate of nitrogenous fertilizers upon application. The current research evaluated the potential of a newly developed slow-release nitrogen fertilizer on maize growth and its behavior in soil under controlled conditions. Six different levels of urea fertilizer (UF) and slow-release nitrogen fertilizer (SRNF) were administered within the field, representing 100%, 85%, and 70% of the recommended application rates. The slow-release nitrogen fertilizer (SRNF) exhibited superior performance regarding growth, yield and nutrient retention in comparison to urea fertilizer (UF). Moreover, minimal ammonia emissions were detected with the employment of the slow-release nitrogen fertilizer (SRNF), while other urea-based fertilizers proved inefficient in mitigating ammonia emissions, despite enhancing various growth and yield parameters. The efficiency in nutrient recovery followed a distinct pattern, with polymer-coated fertilizers demonstrating superiority. The plots treated with SRNF displayed significantly higher growth and yield characteristics compared to those treated with urea fertilizer. In terms of NH3 volatilization, the urea fertilizer (UF) treatment at 100% application rate showed higher emissions (1.99 mg g-1) after a 27-day incubation period, as opposed to the slow-release nitrogen fertilizer (SRNF) treatment (1.68 mg g-1). Leaching data indicated that urea fertilizer treatments led to greater losses of NO3-N (2.01 mg L-1) compared to SRNF treatments (0.88 mg L-1).

Simulation of soil-structure interaction using inelasticity-separated finite element method

The soil–structure interaction (SSI) effect is nonnegligible during the nonlinear seismic response analysis of large-scale or underground structures. However, the computation of nonlinear response of a structure considering SSI effect usually is a time-consuming process because the numerical model should involve the structure itself, a wide-range soil domain and the soil–structure interface, especially for large-scale structure. This study aims to incorporate the inelasticity-separated finite element method (IS-FEM), which is an algorithm recently developed for efficient structural nonlinear analysis, to improve the efficiency of the soil-structure interaction system. To this end, an inelasticity-separated contact element model for modeling the nonlinear behavior of soil and structure interface is developed in this study. To derive the inelasticity-separated governing equation of this model, a reference elastic stiffness is defined so that the normal and shear deformation of any point pair in the presented contact element is decomposed into reference linear and reference nonlinear parts according to this reference elastic stiffness. As a result, the problem of inconsistency between the requirement of IS-FEM for constant initial linear elastic stiffness and the existence of inflection point for the stress versus relative displacement relationship of contact behavior can be solved. Then, the Goodman element formulation for depicting the nonlinear contact behavior is introduced and an interpolation scheme to establish the reference nonlinear deformation field in an element is incorporated. By combining the proposed model with existing inelasticity-separated elements, a global analytical model of the soil–structure interaction system can be established within the framework of IS-FEM. Because the nonlinearity usually occur in some local regions of the global model and the use of the IS-FEM only require performing these operations for a small scale matrix representing local nonlinearity, the computational efficiency of nonlinear structural response analysis considering SSI effect can be improved significantly. The applicability and efficiency of the proposed method is finally verified by two numerical examples.

Three-dimensional numerical analysis of twin tunnelling in two-layered soil strata

Tunnelling induces stress change and displacement in the ground. The excavation of a new tunnel in stratified soil can trigger different patterns of stress redistribution, which may adversely influence nearby tunnels. Research on multi-tunnel interaction has mainly been performed on the assumption of a uniform ground. The effects of different soil stratifications on tunnelling interaction remain poorly understood. In this paper, three-dimensional numerical parametric studies verified by previous centrifuge tests were carried out to analyse the twin tunnelling effects in two-layered soil. An advanced hypoplastic constitutive model that can capture stress-, path-, and strain-dependency of soil behaviour is adopted. Numerical cases investigated include perpendicular twin tunnelling in two sand layers with different relative densities and the location of the interface between the two sand layers. It is revealed that larger settlements and a wider surface settlement trough occur when tunnelling in two-layered soil strata than in a uniform ground. This is because of the wider and larger soil arch induced in two-layered soil strata. The structural response including tunnel deformation, induced bending moment, and induced hoop stress of the existing tunnel can be greater when tunnelling in layered soil strata than in a uniform ground owing to larger stress relief. Moreover, the combination of bending moment and hoop stress can exceed the M−N failure envelope of the structure in layered soil. A conventional simplified assumption of a uniform ground can underestimate of the influence of new tunnel excavation on existing tunnels, resulting in unsafe designs.

Dynamics of structural indices and organic carbon pool across a haplic acrisol under secondary tropical rainforest at Umudike Abia State

Differences in vegetation types over a landscape influences the structural behaviour and organic carbon pool of soils thereby affecting site-specific management decisions. This study aimed at establishing the differences in structural indices and organic carbon pool across a soil under secondary rainforest vegetation. Nine replicates of auger and core soil samples were randomly collected from the site at 0 – 20 cm depth. Soil samples were prepared and analysed at a laboratory. Data obtained were subjected to geospatial analysis using a Geographical Information System (GIS) software package. Results showed that changes in organic carbon storage ranged from 40 – 48 ton / ha, BD ranged from 1.39 – 1.42 mg / m3, clay flocculation index ranged from 50 – 68 %, aggregated silt + clay ranged from 9 – 12 %, clay dispersion index ranged from 32 – 42 %, dispersion ratio ranged from 26 – 32 %, mean weight diameter ranged from 0.75 – 1.05 mm, saturated hydraulic conductivity ranged from 3.1 – 3.8 cm / mins and total porosity ranged from 46.4 – 47.6 %. Regions of weak micro aggregaion dominated the land while regions of increased stability of macro aggregates were dominant. Regions of increased soil organic carbon storage occupied about half portion of the land. Greater portion of the land was noted for increased bulk density, reduced total porosity and saturated hydraulic conductivity. Consequently, there were changes in soil structural properties and organic carbon storage across the studied area.

On-bottom stability of a radial fin integrated surface-laid pipe-section against vertical penetration

This study focuses on the on-bottom stability of surface-laid submarine pipelines during vertical penetration under thermal-induced buckling. Submarine pipelines are susceptible to buckling due to their high slenderness ratio, and the resistance to such displacement relies on pipeline stiffness and soil resistance. To investigate this, laboratory model tests were conducted using a scaled-down pipe section placed on a clay bed. The clay bed was prepared with remoulded Kaolin clay, ensuring uniform moisture content, and the model pipe was scaled down from a typical industry prototype. These tests were conducted in 2D plane strain conditions within a tank, equipped with observation windows to monitor pipe movement and soil behaviour. A significant improvement in the pipe section's penetration resistance and on-bottom stability was observed after incorporating fin in the pipe. The addition of fins altered the earth pressure distribution beneath the vertically loaded pipe, leading to a larger failure mechanism in the adjacent soil. Furthermore, the soil-surface-heaving progressed towards the tank wall with increasing angular distance between the radial fins. Thus, the research demonstrated the effectiveness of radial fins in enhancing the stability and resistance of submarine pipelines against vertical penetration, shedding light on potential improvements in submarine pipeline design and deployment.

Poroelastic effects of chemical loading in consolidation of residual soils

An analytical chemo-hydromechanical model of residual soils was presented in this study. The modeling procedure utilized a unique phenomenological approach, which highlighted some of the macro-mechanical influences responsible for the behavior of residual soils. The macromechanical analysis yielded an extended poroelastic theory. The developed model was applied in solving a typical civil engineering problem of soil consolidation. For a chemical loading treatment, the problem was using requisite boundary conditions. Thereafter, the mathematical software Mathematica was used for solving the ensuing diffusion equations using physico-chemical properties typical of a residual soil sample. Even though the chemical loading was instantaneous, it took some time before its effect could be felt everywhere according to the poroelastic theory. From obtained results the evolution of the generated pore pressure showed increasing segments of the soil returning to their initial state after the passage of the pore pressure front. The vertical displacement showed a slight increase or elevation of the soil surface. The flux of water flow in the soil was initially positive before turning negative, which can be explained by initial successful penetration of the infiltrating liquid until it met increasingly tortuous paths as result of lower permeability. The volume (per unit area) of water leaving the soil after chemical loading demonstrated that a portion of the water flux associated with the infiltrating liquid ends up leaving the soil through the sides. The developed model was later compared with a similar porochemoelastic model found in literature with reasonable agreement.

The Importance of seismic microzonation under the threat of an earthquake of the north anatolian fault in nilüfer, bursa, turkiye

The Nilüfer district experienced the most recent urbanization among the central districts of Bursa in South Marmara region with the completion of rapid construction. Since 358 BCE, many destructive earthquakes were reported on the branches of the North Anatolian Fault (NAF) which caused extensive damage to buildings and loss of life near Bursa city. Besides some studies conducted to define the soil behavior in the vicinity of Bursa, a seismic hazard study in Nilüfer is still lacking. We, therefore, carried out a microzonation study including the following steps. First, an earthquake hazard analysis was conducted and the peak ground acceleration (PGA) values were determined for an expected earthquake. In the next step, MASW (Multi-Channel Analysis of Surface Wave) measurements conducted at 54 points in 28 neighbourhoods of Nilüfer district were evaluated. Soil mechanical parameters were determined at 11 boreholes to assess the liquefaction potential. It was found that almost half of the study area suffers from low damage considering only the vulnerability index (Kg) index, which depends on the site effect. Therefore, in addition to the Kg values, we created a microzonation map using the results of soil liquefaction, settlement, changes in groundwater level, and the average values of spectral acceleration. The study area is classified by four damage levels changing from low to high. Using only the Kg index could not quantify the potential damage level in the study area, thus we showed that the districts of Altınşehir, Hippodrome, Ürünlü and Alaaddinbey, Ertuğrul, 29 Ekim, 23 Nisan, Ahmetyesevi and Minareliçavuş were identified at potentially high-risk damage zones. The results of this study clearly showed that considering the Kg index, which depends only on the local site effect, may lead to inadequate damage values.

Quantifying Desiccation Cracks for Expansive Soil Using Machine Learning Technique in Image Processing

The formation of desiccation cracks has detrimental effects on the hydraulic conductivity that affects the overall mechanical strength of expansive soil. Qualitative analysis on the desiccation cracking behaviour of expansive soil provided understanding of the subject based on various concepts and theories, while quantitative analysis aided these studies through numerical supports. In this study, a machine learning technique in image processing is developed to evaluate the surface crack ratio of expansive soil. The desiccation cracking tests were conducted on highly plastic kaolinite slurry samples with plasticity index of 29.1%. Slurry-saturated specimens with thickness of 10 mm were prepared. The specimens were subjected to cyclic drying-wetting conditions. The images are acquired through a digital camera (12 MP) at constant distance to monitor the desiccation cracks. The images are then pre-processed using OpenCV before crack feature extraction. In this study, a total of 54 desiccation crack images were processed, along with 8 images from trial test to train the model. The processed images are used to quantify the desiccation cracks by evaluating surface crack ratio and average crack width. It was identified that the accuracy of the model for the quantification of surface crack ratio and average crack width were 97.24% and 93.85% respectively with average processing time of 1.51s per image. The results show that the model was able to achieve high accuracy with sufficient efficiency in determining important parameters used for crack characterization.

Selenate simultaneously alleviated cadmium and arsenic accumulation in rice (Oryza sativa L.) via regulating transport genes

Cadmium (Cd) and arsenic (As) have contrasting biogeochemical behaviors in paddy soil, which posed an obstacle for reducing their accumulation in rice (Oryza sativa L.) simultaneously. In this study, selenate exhibited a more effective ability than selenite on simultaneous alleviation of Cd and As accumulation in rice under Cd-As co-exposure, and the mechanisms need to be further investigated. The results showed that selenate significantly decreased the root Cd and As contents by 59%–83% and 43%–72% compared to Cd-As compound exposure, respectively. Correspondingly, it significantly down-regulated the expression of uptake-related genes OsNramp5 (87.1%) and OsLsi1 (95.5%) in rice roots. Decreases in Cd (64.5%) and As (16.2%) contents in shoots were also found after selenate addition. Moreover, selenate may promoted the reduction of As(V) to As(Ⅲ) and As(III) efflux to the external medium, resulting in decreased As accumulation and As(Ⅲ) proportion in rice shoots and roots. In addition, selenate could promote the binding of Cd (by 14%–24%) and As (by 9%–15%) in the cell wall, and significantly reduced the oxidative stress by elevating levels of antioxidant enzymes (by 10%–105%) and thiol compounds (by 6%–210%). Additionally, selenate significantly down-regulated the expression of OsNramp1 (49.3%) and OsLsi2 (82.1%) associated with Cd and As transport in rice. These findings suggest selenate has the potential to be an effective material for the simultaneous reduction of Cd and As accumulation in rice under Cd-As co-contamination.

Centrifuge modeling-of-models investigation on earthquake-induced excess pore pressure behavior of silty sand

Two centrifuge experiments conducted at Rensselaer Polytechnic Institute (RPI) aimed to evaluate the effectiveness of the used centrifuge scaling laws and validate results obtained within the project, related to the liquefaction behavior of silty sand soils under simulated field drainage conditions. These experiments, replicating a 5-m thick silty sand layer under 1 atm overburden pressure and featuring a double drainage condition, were performed at two different centrifugal accelerations. Due to the difficulties encountered in saturating silty sand, this paper presents a bottom-up saturation method, verified through assessments of remaining air volume after saturation. Despite differing g-levels, the tests consistently demonstrated similar behaviors in terms of acceleration, pore pressure buildup and dissipation, and stress-strain responses, validating the saturation and modeling technique for silty sand.

Numerical simulation of impact effect for damage assessment of highway bridge abutments

ABSTRACT Bridge abutments are often damaged by girder impacts during major earthquakes. Very limited studies have been conducted. None of the past studies have incorporated abutment damage as an integrated system, i.e. the interaction between the deck and the back wall as well as between abutment and backfill. First, the reliability of the numerical model for damage assessment is validated with the result obtained from the shaking table test. Second, numerical simulations of the impact effect were carried out on four abutments with different shapes and dimensions of wing wall. The developed numerical models can simulate the nonlinear backfill soil, the backfill-back wall interface, and damage to reinforced concrete with the strain rate effect of the concrete and steel reinforcement. Parametric studies were conducted on the influence of the nonlinearity of the backfill soil, back wall-to-backfill friction, constitutive law of concrete, hourglass ratio, and impact energy. The results show that the nonlinear behaviour of the backfill soil and wing wall plays a significant role in the impact force on the back wall behaviour. Since poundings can be repetitive, this study confirms that the velocity of the initial impact of a bridge deck can precisely predict the severity of abutment damage.

The improved cyclic resistance of bio-treated sands with various gradations for liquefaction mitigation: Density increase and/or cementation?

MICP (microbial induced calcium carbonate precipitation) method shows a huge potential in solving geological and geo-environmental engineering problems, such as liquefaction mitigation, soil remediation, erosion control, slope stabilization and dust control., due to its low-carbon, sustainable and undisturbing character. For the liquefaction mitigation, previous studies showed the remarkable enhancement in cyclic behavior of bio-cemented soils. Little attention has been paid to how soil gradation affects the effectiveness of MICP method in enhancing soil properties, which is one of the key factors of soil mechanical behavior. MICP method has been mainly used in fine sands (mostly <1 mm) with narrow gradation and a certain number of particles smaller than 75 μm. As a result, few papers discussed the application of bio-cementation to soils with larger grains. In addition, the respective contributions of density increase and cementation on cyclic resistance enhancement is still not clear. In this study, a fine sand (0.1–1 mm), a coarser sand (1–5 mm), and a mixture of both, were used, featuring a larger mean size (d50 mm) and uniformity coefficient (Cu) than in most previous studies. In this study, cyclic undrained triaxial tests were performed to analyze the liquefaction potential of loose and dense untreated specimens, and initially loose treated specimens. Results show that sand gradation has a great influence on the cyclic behavior and MICP effectiveness. For all the sands, the MICP treatment gives rise to a significant increase in cyclic resistance and mitigates liquefaction. This enhancement is due to the formation of cementitious precipitates in the pores or on the surface of particles, which creates (1) bridges between particles and/or change in grain characteristics (i.e., size, roughness, angularity), and (2) an increase in density. For sands with various gradations, these two effects differ in magnitude: in the coarsest sand, the effect of density increase appears to be predominant whereas, in the finest and medium sands, the formation of bonds seems to play the major part. These results are important to evaluate the possibility of using this method to improve cyclic resistance in various sands, and to compare the treatment effect with other techniques.

Investigation on Strength and Flexural Behavior of PVA Fiber-Reinforced and Cemented Clayey Soil

Adding cement to soft soils may lead to brittle behavior and the occurrence of sudden damage. Methods to further improve the tensile and flexural properties of cemented clay are noteworthy topics. This paper mainly focuses on the effect of cement and moisture content on the strength and flexural properties of cemented clay reinforced by PVA fiber. The selected clayey soil was a kaolin with cement content of 5%, 10%, and 15% and moisture content of 50%, 56%, 63%, and 70%. The results show that the incorporation of 0.6% fiber can effectively improve the deformability of cemented clay in unconfined compression tests (UCS). The strengthening effect of fiber, as seen in the peak strength and post-peak strength of UCS, was significantly related to cement content. As the water content increased, the compressive strength of the fiber-reinforced cemented clay decreased, but its load-bearing capacity enhanced. When the cement content was 15%, the splitting tensile strength of fiber-reinforced cemented specimens increased by 11% compared to cemented soil, but the deformability of the specimens became poor. In the cement-content interval from 5% to 10%, the bending toughness was significantly improved. Sufficient cement addition ensures the enhancement of PVA fibers on strength and flexural properties of cement-stabilized clayey soil.