Soheil Ghadr

• BSc, MSc, PhD
• Postdoctoral researcher at Texas State University

Sand–bentonite (SB) serves a crucial role as a landfill liner for waste containment and environmental protection. However, the challenge of insufficient strength in SB liners poses risks of failure and hazardous substance release. To address this, our study introduces an innovative approach by incorporating the shredded facemask (FM) and colloidal...

The study examines the effects of pressmud (PM), an innovative, sustainable, and beneficial alternative for soil treatment, on the hydromechanical behaviors of sand–bentonite (SB) through a series of laboratory tests, including unconfined compressive strength (UCS), free swelling, and 1D consolidation. SB mixtures with 10 and 15% bentonite (by sand...

The use of discarded tire in sand to mitigate liquefaction has received much recent interest. Most of the published research addresses the dynamic response of compacted tire-reinforced soils. Whilst compaction is indeed an integral part of remediation of liquefiable soils, prospects of safeguarding coarse soils against softening and liquefaction in...

The concept of “loessification,” introduced by Berg in 1916, describes the transition of non-loess ground to loess ground via weathering. The theory dismisses the aeolian deposition phase in loess cycle, and is heavily centred around pedogenic processes, climate actions and interaction between residual sands/silts and neighbouring soil sequences. T...

A programme of consolidated undrained triaxial shear tests is conducted on two residual and deltaic sands of similar size and different shape. Dry pluviation was used to generate an initial random open packing ahead of isotropic consolidation. Overall, both residual and deltaic sands exhibit a non-flow (NF), strain hardening (HS), dilative response...

Mudstone soils (MS) are widely distributed in southern Taiwan and have an inherent proclivity to geological damages and failures. However, the use of traditional and non-traditional techniques to treat MS remains a challenge and is an area relatively unexplored due to the soils' distinct and sophisticated features. This study examined the hydromech...

Organic clays are ideal habitats for flora and fauna. From a geotechnical perspective, organic clays are soft, weak, variable, heterogeneous, and flocculated. Portland cement is a universally common stabiliser. However, some organic acids in soil inhibit full hydration and expose cementation products to rapid dissolution. This paper investigates s...

Geological hazards, such as landslides and soil erosion, are frequently found in regions where mudstone soils are prevalent. These soils can also present challenges for the construction of infrastructure, including roads, railways, and other facilities. While various methods exist for addressing the mechanical and hydromechanical properties of muds...

Due to the COVID-19 pandemic, personal protective waste generation has increased worldwide. Given this problem, urgent waste management methods are required to reduce waste surcharge to the environment. The present study tries to clarify the question using particle-level modeling combined with 36 undrained cyclic triaxial shear tests. The physical...

The rapid response to the COVID-19 pandemic has resulted in increased municipal waste in the form of used face masks (FMs), which pose a global threat to the environment. To mitigate this, the study explores the applicability of shredded FMs as alternative reinforcing material in sands. Laboratory-grade Ottawa sand and naturally collected sea sand...

The fractal framework could help to better understand the inherent variability of granular materials' behaviour, how these relate to structures at the micro-scale, and how understanding, rationalizing and reducing the randomness at the micro-scale can facilitate the design at the macro-scale. particle fractal packing structure behaviour

The engineering properties of particulate materials are the collective manifestation of interactions among their constituent particles and are structures within which particles adopt their spatial arrangement. For the first time in the literature, this paper employs an extended concept of ‘fractals’ to show that materials constituting particles of...

In this study, the effects of hydrophilic (HPI) and hydrophobic (HPO) nanosilicas (NS) on the hydromechanical properties of mudstone soil were investigated in a laboratory. Mudstone soil samples treated with different contents (0.3%, 0.6%, 0.9%, and 1.2%) of both types of NS were prepared and rigorously examined through standard Proctor compaction,...

The ground is a natural grand system; it is composed of myriad constituents that aggregate to form several geologic and biogenic systems. These systems operate independently and interplay harmoniously via important networked structures over multiple spatial and temporal scales. This paper presents arguments and derivations couched by the authors, t...

Peat occurs abundantly in wetlands across Iran, particularly around the disappearing Urmia Lake. Conventional chemical stabilisation has been widely used to tackle the high compressibility and shrinkage potential of peat. Whilst effective, this generally reduces the carbon storage capacity of peat. Exotic stabilisers such as nano-silica (NS) have b...

Salt lakes are major sources of dust. Formation of natural evaporitic salt crusts can reduce the dust efflux, but protection is dependent on environmental conditions and the mineralogical composition of lakebed deposits. Chemical stabilization with conventional additives can benefit in further reducing the dust efflux. These however disrupt the soi...

The contractive behavior and flow failure in saturated binary granular soils have been studied by many as functions of their physical properties [gradation, mean particle size, fines content (FC), and packing quality] and mean effective stress, stress history, and cyclic stress amplitude. Nevertheless, little is known on the interplays between fram...

Progressive diffusion of CO2 into cement-based construction products and consequent carbon uptake has received considerable attention in recent years. Studies have promoted the capacity of soils mixed with construction cement wastes to function as a carbon sink, which has largely been overshadowed in emissions inventories. There is however little c...

In many urban cities due to the enormous growth in the number of vehicles, scrap rubber disposal has been a critical environmental problem. In recent years, important research efforts have been dedicated to investigating the use of scrap rubbers in civil engineering applications, like recycling or reuse of scrap rubbers is the preferred possibility...

Whether the so-called double porosity in soils with a loose and natural packing state is a concept with real-world implications is a fundamental yet controversial question in the study of cyclic undrained shear behaviour of fibre-reinforced silty sands. An attempt is made here to clarify the question by means of particle-level modelling combined wi...

Colloidal nano-silica (NS) hydrosols are electrochemically stabilized, polymerized amorphous silica in low viscosity solutions, and in the form of hydrated gels, silica globules or pellicles. Compared to applications in concrete technology, the use of silica-based binders for groundwork applications has received little attention. Silica-based hydro...

Colloidal nanosilica hydrosols are electrochemically stabilised polymerised amorphous silica in low viscosity suspensions. They have no known adverse impact on soil health and ecosystem service functions, thereby having a scope for use in groundworks as an alternative low-viscose stabilising material. Six grades of colloidal nanosilica are synthesi...

This study investigates the dependency of steady states on anisotropy in unreinforced uniform angular silica sands and those reinforced with micro-synthetic fibres. In doing so, the principal stress orientation varies from 15° to 60° for an intermediate principal stress ratio of 0.5 and 1.0 and the initial effective consolidation stress of 200 kPa....

The contribution of fibers to the strength of fiber-reinforced soils is dependent on multiaxial stress space. This study furthers knowledge on the dependency of steady states on anisotropy in unreinforced and reinforced (with 1.5% microsynthetic fibers) well-sorted sands with different shape and size properties. For this purpose, the direction of p...

Uncertainty in ground datasets often stems from spatial variability of soil parameters and changing groundwater regimes. In urban settings and where engineering ground interventions need to have minimum and well-anticipated ground movements, uncertainty in ground data leads to uncertain analysis, with substantial unwelcomed economical and safety im...

Building on/with expansive soils with no treatment brings complications. Compacted expansive soils specifically fall short in satisfying the minimum requirements for transport embankment infrastructures, requiring the adoption of hauled virgin mineral aggregates or a sustainable alternative. Use of hauled aggregates comes at a high carbon and econo...

Among the plethora of studies on anisotropy in fibre-reinforced sands, there exist conflicting views on effects on the steady-state deformations of initial packing. These conflicting views are further confused by strictly limited experimental evidence on flow in complex loading environments where the principal stresses rotate whereby shearing and t...

Lime Cake (precipitated calcium carbonate PCC), a by-product of sugar production, is proposed as a stabiliser for improvement of loose silty clayey loams. Two inorganic pedogenic and organic precipitated calcium carbonate polymorphs are artificially synthesized into a base loosely compacted loamy soil. Formation, micromorphology, quality of cementi...

The stress–strain and stress path characteristics of sands are influenced by their grain size, shape, and packing. Morphological characteristics and size of particles play important role on the undrained shear strength of sands. Often, effects of these parameters are complex and cannot be easily distinguished. This study advances the knowledge of t...

For the geological disposal of highly contaminated wastes, medical or other sorts, clay barrier systems are commonly designed and used. The engineered liners contain buffer material which is often carefully proportioned mixtures of pure bentonite and sand. Bentonite is an active clay mineral with very low hydraulic conductivity and extremely high e...