Mangrove ecosystems are globally recognized as potent natural climate solutions due to their exceptional potential for carbon sequestration. Yet, they are rapidly declining under mounting anthropogenic pressures such as coastal urbanization, sea-level rise, and habitat conversion. This study investigates the viability of establishing Avicennia marina (grey mangrove) in an arid sandflat (known as sabkha) at two contrasting locations - Qurayyah and Rahimah - in the Eastern Province of Saudi Arabia. The main objective of this study was to compare the survival rate of A. marina mangrove seedlings between five soil amendments, namely, control, peat moss, Multi-microbial consortium (MMC) fertilizer and red soil. Results showed that peat moss, included for its high moisture retention and nutrient provisioning capacity, consistently achieved higher survival rates at both sites. In addition, peat moss consistently improved seedling survival at both sites. Multi-microbial consortium is recognized for its role in enhancing plant tolerance to salinity and facilitating nutrient uptake, particularly under nutrient-poor and saline conditions such as sabkha soils. In this study, Multi-microbial consortium -treated seedlings demonstrated notable improvements in nitrogen assimilation and chlorophyll content, highlighting the symbiont’s contribution to enhancing physiological resilience under environmental stress. Notably Rahimah showed overall better survival outcomes than Qurayyah, likely due to its proximity to tidal waters. These findings indicate that the combination of appropriate soil amendments and closeness of sabkha to coastal waters is critical for improving mangrove survival in such environments. Overall, integrating targeted soil amendments with strategic site selection and optimized hydrological conditions could substantially enhance mangrove establishment, supporting climate-adaptive restoration in arid, hypersaline coastal systems.

This paper presents a case study of a pilot project on using novated Pre-Stressed High-Strength Concrete (PHC) Piles technology for a potential support to the large foundations of Steel Plate Manufacturing Plant, which to be installed on an area that contains sabkha soils saline, loose, and water-saturated sands in Ras Al Khair Industrial City, Saudi Arabia. The key highlight of this project is the successful installation and testing of Prestressed High-strength Concrete (PHC) piles likely the first such application within Saudi Aramco, and possibly within the Kingdom of Saudi Arabia. This paper presents the load-settlement and the load-displacement diagrams for the tested PHC piles and identifies the bearing capacity of some of these piles at the job site. The study summaries the bearing capacities of the tested PHC piles to be considered for the detailed design of future project packages. PHC Pile foundation reduces the settlement of structures and improves bearing capacity of foundation; and the new pile technologies are of little noise and reduce damage to pile during the installation. The PHC piles, characterized by a hollow core and prestressed concrete design, are typically produced with outer diameters ranging from 300 mm to 1200 mm and engineered to endure high axial loads and bending moments, making them suitable for challenging ground conditions such as sabkha.

The available seismic response parameters do not accurately represent the unusual behavior of sabkha soils; the weak soils with high salt content. This study aimed at developing seismic response parameters for sabkha soils in Ras Al-Khair Industrial City, Saudi Arabia. These sabkhas revealed an anomalous response to geophysical and dynamic tests. The methodology involved analysis of extensive available data to come up with micro-zonation based on subsurface strata. Field and laboratory explorations were conducted, and 3-D seismic response was numerical simulated. This study identified an anomalous dynamic response of sabkha soil, as it has higher shear modulus. The spectral accelerations values, for both short-period and long-period, have been found to differ from the values specified in local codes. Scientific contributions include the localized liquefaction potential along the boundary of the contrasting strata. The site-specific seismic response is found to be not only dependent on the structure and fabric of the soil, but also highly affected by the pore fluid. Originality appears in utilizing 3-D modelling/ simulations to produce liquefaction hazard maps. It is concluded that 3-D modelling/simulations lead to a more realistic representation of ground conditions. The seismic parameters are recommended to be revised based on 3-D modelling that considers the type of pore fluids.

Synergistic Influence of Cement–Lime Stabilization on the Mechanical Properties and Mineralogical Changes of Sabkha Soils from Aïn M’lila

Iraq is located within the arid and semi-arid region which include large areas of Sabkha soil particularly in the southern regions. Stabilization of properties of Sabkha soils in terms of strength, durability, and cost is required from engineering point of view. In this study the synthesis of a new chelating Schiff's base of Furfural with Metal ions (SFM) was used for stabilization Sabkha soil. The present study investigates the possibility of using the SFM to enhance Sabkha soil properties in the southern regions in Iraq. In this study, experimental approach was employed to investigate the properties of treated and untreated Sabkha soil. In laboratory tests, Sabkha soil samples have been mixed with 2%, 4%, and 6% of SFM for mineralogical tests whereas other samples tested in order to identify the physical and mechanical properties of the treated samples. The stabilization mechanisms of treated sabkha soil have been investigated using modern approaches, such as Scanning Electron Microscope (SEM), Energy Dispersive X-ray analysis (EDX) and X-Ray Diffraction analysis (XRD). Sabkha soil, when mixed with 4% and 6% SFM, has been observed to transform into a solid material potentially suitable for use in the sub-base layer of rigid pavements. The study revealed that the compressive strength of the treated Sabkha samples was increased from 51 kPa to 402 kPa. Compared to untreated Sabkha soil the improvement ratio of treated sabkha soil increased from 119% to 443%. However, results of triaxial test showed that the cohesion increased by133.6 kPa without affecting the angle of internal friction. While the results of direct shear test showed that the angle of internal friction increased from 35 to 41 degrees. The soaked CBR values showed an increase with the addition of SFM at concentrations of 0%, 2%, 4%, and 6%, rising from 11% to 21%, 32%, and 58%, respectively. Added SFM values were increases this showed Sabkha soil is suitable material for to be a pavement foundation course. Based on the wetting and drying testing results, stabilized Sabkha soil with 6% SFM lost roughly 8.4% of its weight over time. In contrast, soil stabilized with 4% SFM and 2% SFM lost approximately 10.5%, and 15.4% of its weight respectively.

Saline sabkha soils pose a major challenge for geotechnical engineering because of their low bearing capacity and high settlement potential. The purpose of this research was to evaluate the behavior of stabilized sabkha soil under axial stress after geopolymer treatment utilizing the mix and compact method. A comprehensive numerical analysis, validated by experimental results, was conducted to study the load–displacement behavior of sabkha soil in its natural and treated states. A parametric study using the finite element method was performed to examine the effects of the thickness and diameter of the geopolymer-treated soil layer on the ultimate bearing capacity (UBC). Response surface methodology and ANOVA were employed to develop and evaluate a predictive model for UBC as a function of the dimensionless ratios Hm/Df and Dm/Df. The results revealed that the geopolymer treatment significantly enhanced the load-bearing capacity of sabkha soil by increasing the thickness and diameter of the treated soil layer. However, a higher ratio of Dm/Df than 2 adversely affected soil performance when the Hm/Df ratio was less than 0.6. The study also demonstrated that geopolymer is a novel and environmentally friendly technique for stabilizing sabkha soils, as it utilizes waste materials (fly ash and mine tailings).

The soil in the coastal areas of the Abu Dhabi emirate is of the Sabkha type and is mainly composed of thin intercalated layers of sand, clay, and evaporites. The water table in these areas is shallow. Subsurface water that accumulates above the "hardpan" near the surface in topographic depressions is often mistakenly identified as a water table rise. The rapid urban expansion during the last twenty years, along with the development of extensive green areas in and around Abu Dhabi City, has exacerbated the waterlogging problem in urban areas. This issue is prevalent in areas with poorly permeable soil under climate change in terms of the change in precipitation magnitude and pattern. The resulting water ponds can range in size from a few square meters to over one square kilometer. Additionally, elevated groundwater levels in these areas can lead to flooding basements, garages, infrastructure, subsurface utilities, and transport routes, and might mobilize pollutants on the ground surface. The novelty of this study lies in identifying the primary source of water, which is primarily the leaching of return flow from irrigation above the shallow hardpan, a situation worsened by the rising water table in Sabkha soil. Previous solutions, such as soil replacement, soil treatment, and pumping water to transport it to the sea, have proven costly, unsustainable, and technically or economically infeasible in certain regions. In contrast, a novel, optimal, effective, and sustainable groundwater control system was simulated using a newly developed, calibrated 3-D groundwater flow model that covers nearly two-thirds of the UAE, encompassing both the surficial and deep carbonate aquifers. This system operates by pumping water from the ponds and injecting it into the deep hypersaline aquifer. The simulation indicated a water table decline of 1.5 m after one year across a large zone of the study area.

Performance assessment of a foundation resting on reinforced collapsible Sabkha soil by deep soil mixing columns using machine learning analyses

In this paper, the effects of prestressing geosynthetic reinforcement on settlement reduction in embankments overlying locally weak zones are investigated through numerical analyses using the PLAXIS finite element code. The selected case study focuses on the reinforcement of a road embankment spanning approximately 11 km across soft sabkha soils in the Chott El Hodna region of Algeria. The construction site presents significant challenges due to the presence of locally weak zones with very low bearing capacity and liquid consistency, making them unsuitable for supporting road embankments without the risk of excessive differential settlements. The study examines the influence of key parameters, including the strength of the underlying weak zones, the magnitude of the prestressing force, and the tensile stiffness of the geosynthetic reinforcement. Numerical results indicate that incorporating prestressed geosynthetics significantly improves the settlement response of the embankment, particularly in areas overlying locally weak zones. This technique enhances load distribution, minimizes localized pressure on weak zones, and mitigates the risk of excessive differential settlements.

In Saudi Arabia two methods of soil improvement have been customarily employed. They are soil improvement by means of stone columns, and soil improvement by means of controlled modulus columns, that is CMC. Each of these methods have their own challenges to offer. Experience has shown that the sub-surface geology of the coastal areas of Saudi Arabia are marked with deep layers of poor soil termed locally as sabkha soil. Test results have determined that sabkha soil is known to have low shear strength, high soil compressibility, and high concentration of chlorides and sulphates which are corrosive to concrete, steel, and other construction materials. Design of foundations over a sabkha deposit remains a challenge and requires soil improvement. The CMC installation utilizes reverse flight augers, which displaces the soil laterally. However, it offers a huge challenge of post-operation trimming and cutting of CMCs. for stone columns, soil is removed during the drilling operation creating environmental issue. It also offers challenges as the huge impact during its operation are likely to damage the underground utilities. The environmental issues thus created can pose yet other challenge. This research paper is a case study that collates the experiences of soil improvement methods employed on a project in Saudi Arabia – vis-à-vis their advantages and the challenges encountered.

In Saudi Arabia two methods of soil improvement have been customarily employed. They are soil improvement by means of stone columns, and soil improvement by means of controlled modulus columns, that is CMC. Each of these methods have their own challenges to offer. Experience has shown that the sub-surface geology of the coastal areas of Saudi Arabia are marked with deep layers of poor soil termed locally as sabkha soil. Test results have determined that sabkha soil is known to have low shear strength, high soil compressibility, and high concentration of chlorides and sulphates which are corrosive to concrete, steel, and other construction materials. Design of foundations over a sabkha deposit remains a challenge and requires soil improvement. The CMC installation utilizes reverse flight augers, which displaces the soil laterally. However, it offers a huge challenge of post-operation trimming and cutting of CMCs. for stone columns, soil is removed during the drilling operation creating environmental issue. It also offers challenges as the huge impact during its operation are likely to damage the underground utilities. The environmental issues thus created can pose yet other challenge. This research paper is a case study that collates the experiences of soil improvement methods employed on a project in Saudi Arabia – vis-à-vis their advantages and the challenges encountered.

For projects such as airports and road paving, an appropriate foundation must be developed in Sabkha soil, which requires a trustworthy assessment of soil-bearing capacity. When heavy traffic is expected to result in substantial wheel loads throughout pavement construction and maintenance, the plate load test helps solve these issues with subgrade and sub-base layer design. This work aims to investigate and assess the geotechnical behavior regarding soil strata from one area in southern Iraq: Sabkha. Conversely, a comparison is made between subgrade response modulus and soil-bearing capacity determined by field plate load tests and traditional laboratory investigations. The data demonstrated that the values related to Ks in the consolidation test rose as a ratio of pre-consolidation pressure of 45% and dramatically dropped with an increase in applied stress that is vertically applied below pre-consolidation stress. Furthermore, PLT data demonstrated that when pressure was applied, the modulus of the subgrade reaction did not follow a regular pattern. At the beginning of the loaded stage, after the pre-consolidation stress, Ks values at testing points 2 and 3 were high. After that, Ks abruptly decreased, particularly when the applied pressure surpassed the pre-consolidation stress before being constant again. A detailed discussion is given on the effects of stress distribution and test conditions on the elasticity stress curve's shape and the subgrade reaction modulus.

Salt-encrusted desert flats or sabkha soil, which particularly formed in arid and semi-arid zones, have raised a noticeable concern because of low bearing capacity and high compressibility. this study is aimed to explore the feasibility of stabilizing Omani sabkha using environmentally friendly stabilizer through Cement Kiln Dust (CKD). Untreated and treated sabkha were characterized using standard proctor compaction test, unconfined compressive strength (UCS) and California Bearing ratio test (CBR). Results show that utilizing 7.5% binder that contained 50% Cement Kiln Dust improved the overall properties of sabkha soil and it can be used as sub-base layers.

This study explores the application of stone columns to improve the bearing capacity of sabkha soil for the construction of a Lattice Communication Tower foundation in the Eastern Province of Saudi Arabia. Geotechnical investigation report, an on-site footing loading test to evaluate the foundation's bearing capacity and settlement behavior following stone column installation, and post-cone penetration tests (CPT) to assess soil densification are all part of the study data. The uppermost 4 m of the soil profile comprise a medium to dense layer of sand with silt, followed by a 12-m layer of weak sabkha soil (SPT, N less than 4). Below the sabkha layer, the strata exhibit varying densities, ranging from medium to dense and very dense layers, extending to the maximum depth of investigation. The comparison of Pre- and Post-CPT data revealed significant improvements in the sand and silt layer above the sabkha layer, as well as moderate improvements in the upper portion of the sabkha layer. However, the majority of the sabkha soils and underlying soil layers did not show significant improvement. Plaxis 3D numerical models were employed to provide insights into the performance of the composite area encompassing stone columns and the surrounding soil. Comparing field tests and numerical models showed that neglecting stone column installation effects in numerical models led to overestimating settlements. However, when examining the field data and numerical results with a raised coefficient of lateral earth pressure when of K∘=2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${K}_{^\\circ }=2$$\\end{document}, a distinct alignment between settlement values consistent with those derived from field testing. The findings highlight the importance of including site-specific conditions and installation effects in numerical modeling to accurately predict the behavior of stone columns in sabkha soils.

Improvement of Sabkha Soils Using Cement and Marble Powder

Sabkha soils can be found all over the world specially, in hot arid areas. This soil is regarded as problematic because of its low bearing capacity and excessive settlement which creates problems to any type of structures. Consequently, the aim of this paper is to predict the behavior of strip footing founded on reinforced Sabkha soil using three different methods utilizing finite element method analysis. First, beneath the footing, a compacted sand layer mixed with randomly dispersed polypropylene fibers (PP) is used. Moreover, a compacted sand layer reinforced with geogrids is used. Finally, investigate the effect of using a sand-rubber mixture layer below as a foundation soil below the footing. The effects of these methods on strip footing bearing capacity and settlement were studied using the finite element method software Plaxis 2D ver. 21. Therefore, it was determined that adopting these procedures boosts the strip footing bearing capacity by a substantial amount, particularly when utilizing the first method which is utilizing the fiber reinforced sand layer over the weak sabkha soil layer. Also noticed was a reduction in soil vertical displacements under foundation for the same values of stress applied to footing.

Abstract Excavation in Sabkha soils, found in coastal regions of Saudi Arabia, presents complex challenges in construction due to their unique geotechnical characteristics. These soils are known for their high compressibility, collapsibility, and variable sediment deposition, rendition them unsuitable for excavation without adequate support systems. As urbanization and industrial activities continue to expand into these areas, the demand for effective excavation support systems becomes gradually critical. This study investigates the feasibility of employing Deep Soil Mixing (DSM) as an excavation support system in Sabkha soils. Utilizing finite element analysis through PLAXIS 3D software, the behaviour of DSM walls in Sabkha soil under various conditions is rigorously simulated. The findings of this research establish that DSM walls can serve as an efficient excavation support system in Sabkha soils, provided that crucial factors, particularly excavation depth, are considered during the design phase. The study demonstrates that properly designed DSM walls, in combination with appropriate anchoring methods, can substantially reduce horizontal displacement and bending moments, ensuring the stability of excavations in Sabkha soils. The research highlights the need for further investigations into the cost-effectiveness of DSM walls in comparison to other excavation support options to evaluate the economic feasibility of using DSM in Sabkha soil applications.

This study delves into the potential of using modified sabkha soil, a low-quality material, as a cost-effective solution for road construction in Kuwait, a country grappling with resource limitations. The research evaluates the effects of adding different percentages of bitumen (0%, 4%, 8%, and 10%) to sabkha soil samples, specifically looking at their load-bearing capacity under long-term soaking conditions. The findings indicate that adding up to 8% bitumen enhances the soil's geotechnical properties and its load-bearing capacity. However, any further addition leads to a decline in these properties. Importantly, the soil's load capacity shows significant improvement under soaked conditions. These encouraging laboratory results suggest that utilizing waste sabkha soil could pave the way for effective soil waste management techniques, thereby addressing environmental concerns related to sabkha soil disposal.

Roads designers are often faced with the challenge to design a stable solid foundation on top of Sabkha soil, which has high salt content, very low bearing capacity and loosing of its strength upon wetting. Roads constructed on this type of soil are mainly facing problems of settlement due traffic loads and very low bearing capacity of Sabkha soft soil. This type of soil need to be stabilized using one of the stabilization techniques. The aim of this paper is study and evaluate the sabkha soil problem, which exist in North-West of Libya, where the main road connecting Libya with Tunis passed. This paper illustrates the results of using Cement Kiln Dust (CKD) in Sabkha soil stabilization. The results show a considerable improvement of sabkha soil properties based on tests conducted specially CBR values.

Objectives: Sabkha soil is widely formed in the Arabian Gulf in the Kingdom of Saudia Arabia, particularly along the coastline. Over the past 25 years, numerous studies have been conducted to understand and characterize sabkha soil and increase its strength and durability. To enhance the geotechnical properties of Sabkha soil using an environmentally friendly electrokinetic stabilization method. From a geotechnical perspective, the construction process heavily depends on improving weak soil strength, durability, and treatment cost. The presence of water, high salinity, low shear strength, and low specific gravity are the soft geotechnical features that need to be enhanced before any construction on sabkha soil. Methods/Analysis: The electrokinetic stabilization method was applied to extract salty particles and enhance the geotechnical properties of sabkha soil. The voltage gradient of 40 V was applied for 1, 3, and 7 days using stainless steel electrodes. Findings: The result showed an outstanding improvement of sabkha soil geotechnical properties where the shear strength was increased from 116 to 165, 230, and 360 kPa for Rabigh I (RI), 122 to 155, 254, and 371 kPa for Rabigh II (RII), and for Rabigh III (RIII), the shear strength was improved up to 405 kPa. The moisture content decreased from 34.5 to 16.8% for RI, 35.2 to 15.9% for RII, and 37.5 to 14.7% for RIII. Novelty and applications: Experimental results demonstrated that all parameters were improved massively by increasing the voltage gradient and operational time. This technique is highly recommended to strengthen weak soil and improve geotechnical properties.