Our Terminology
At Geo-Solutions we use an array of different terminology when discussing our expertise, solutions and techologies. Below is a table of how we define our most commonly used terms.
| Term | Definition | Acronyms, Related Terms | Category |
|---|---|---|---|
| "Open" trench | The portion of a slurry trench not yet backfilled; for self-hardening slurry, the portion where the slurry has not yet set. | Construction or Design Term | |
| Absorptive media | Media selected for a permeable wall or soil mixing application that is designed to draw contaminant particles into the media particle to prevent movement. | See also permeable reactive barriers and reagents. | Material |
| Adsorptive media | Media selected for a permeable wall or soil mixing application that is designed to draw and attach contaminant particles to the outside of the media particle to prevent movement. | See also permeable reactive barriers and reagents. | Material |
| Aggregate | Coarse grained, free-draining particulate material like sand, gravel, o crushed stone that can be used for backfilling deep drains and various surface applications. | Material | |
| Auger cast piles | Deep foundation elements installed by augering soils out and grouting the empty hole, often installed with continuous flight auger systems and with steel reinforcement included in the grouted hole. | Acronymn: ACIP, ACP | Technology |
| Auger excavation / LDA | Controlled excavation performed using oversized or large-diameter augers, commonly where access limits conventional excavation. | Acronymn: LDA | Technology |
| Auger mixing | Soil mixing using augers or auger shafts to blend soil with reagent slurry or grout; used for columns, cells, and walls. | See also soil mixing. | Sub-Technology |
| Barge-mounted dredging | Dredging performed from floating equipment to remove or manage sediment from waterways. | Related: dredging from barge, marine dredging. | Sub-Technology |
| Batch plant | A plant used to make reagent slurry or grout and control the weight or volume of slurry/grout components for construction. | Construction or Design Term | |
| Bearing capacity improvement | Methods used to increase the load-carrying capacity of weak soils; soil mixing and rigid inclusions are common examples. | Solution | |
| Bench scale study | A laboratory study using project materials to develop or confirm mixture proportions before full-scale construction. Important in slurry backfill and soil mixing design. | See also mix design. | Construction or Design Term |
| Bentonite | A swelling clay commonly used in various civil engineering applications, including slurry and grout systems to support trenches, improve grout characteristics, and reduce permeability in backfills. | Material | |
| Binder | A reagent such as cement, lime, slag, fly ash, or related material used to bind or improve soil; binder selection depends on objectives and soil/contaminant conditions. Plain-language synonym for many cementitious reagents | See also reagents. | Material |
| Bio-polymer slurry | A polymer-based slurry made from a biodegradable polymer such as guar gum slurry, used to support trench excavation where a permeable trench or drain is desired. | Related: guar gum, polymer slurry, bio-polymer slurry trench method. | Material |
| Blade rotation number (BRN) | A measure of mixing energy expressed as the number of blade rotations through a unit depth. | Acronym: BRN. | Property |
| Blast furnace slag | A non-metallic byproduct of iron and steel manufacturing that is ground into a fine powder and used as a supplement to cementitious materials. Commonly used for slurry trenching and soil mixing to improve strength and permeability. Also known as ground granulated blast furnace slag. | Acronymn: BFS or GS or GGBFS | Material |
| Bulkhead | A waterfront structure application for sheet piling. | Construction or Design Term | |
| Cement kiln dust | A highly alkaline, fine-grained by-product of cement manufacturing that can be used as a supplementary cementitious binder. | Acronym: CKD | Material |
| Cement-bentonite (CB) | A self-hardening slurry made from cement mixed with bentonite-water slurry. Can be used in slurry trenching, grouting, or soil mixing applications. | Acronym: CB. | Technology |
| Chain / trencher mixing | Soil mixing using large chains or trenching machines to blend in situ soil with slurry/grout, sometimes for wall construction. | See also One Pass Trenching. | Technology |
| Chain mixing | A mixing method that uses a chain or trencher equipment to blend soil and reagents, including for some wall and gate applications. | Related: chain trencher, trencher mixing, one-pass trenching, soil mixing. | Sub-Technology |
| Coal ash | One of multiple residual byproducts of burning coal for power. The term often refers to facilities for disposal and storage areas for coal combustion residuals generated from burning coal to produce energy. | See also coal combustion residuals. | Industry |
| Coal Combustion Residuals | Residual byproducts generated from burning coal to produce energy, commonly associated with disposal and storage areas. | Acronym: CCR. Related: coal ash, fly ash. | Industry |
| Cofferdam | A temporary works application for sheet piling and marine services around bridge, dam, or hydro work wherein a tempoorary structure is installed to permit construction below water. | Construction or Design Term | |
| Collection trench | A high-permeability trench designed to collect groundwater or contaminants and convey flow for management or treatment. | Related: deep drain, bio-polymer drain. | Sub-Solution |
| Compaction | Densification of soils at constant water content through mechanical energy that decreases air void volume and increases density. | Different from consolidation. | Principle |
| Compressibility | A measure of soil deformation under load. Often linked to settlement control. | Property | |
| Consolidation | Densification of oil that occurs at varying water content. Consolidation and compaction are not the same though both result in a higher density. | Principle | |
| Constructability review | A preconstruction service used to incorporate construction considerations into project planning, design, and execution to ensure the solution is practical and cost effective. | Construction or Design Term | |
| Construction sequencing | The planned order of construction activities used to integrate design requirements, access, staging, and production constraints. | Related: design-build, project execution. | Construction or Design Term |
| Consulting | Technical services that support planning, design coordination, and construction execution. Constructability reviews and technical evaluations are commonly provided consulting services. | Related: technical evaluations, constructability reviews. | Solution |
| Contaminant migration | Movement of contaminants through soil, sediment, or groundwater that remediation and containment systems are designed to limit. | Related: contaminant transport, plume migration. | Principle |
| Continuous flight auger | A continuous helical auger system used to excavate soil and place grout for auger cast pile installation. | Acronym: CFA. Related: auger cast piles. | Construction or Design Term |
| Control of water | One of the primary ground improvement principles focused on removal or control of groundwater. | Principle | |
| Conventional excavator | Standard earthmoving equipment used for excavation, grading, removal, or slurry trench construction where access and geometry allow. | Related: excavator, earthwork equipment. | Construction or Design Term |
| Cutoff wall funnel | The low-permeability portion of a funnel-and-gate system that intercepts and directs groundwater toward a treatment gate. | Related: funnel wall, cutoff wall. | Sub-Solution |
| Cutoff wall | A low permeability subsurface barrier or wall used to reduce, control, or collect groundwater flow or contaminant migration depending on design. The element is installed vertically to control horizontal movement | See also vertical barrier or barrier wall. | Solution |
| Dam grouting | Grouting of soil or rock used to control seepage below and through dams. | See also permeation grouting | Sub-Solution |
| Darcy’s law | A relationship for one-dimensional water flow through soil expressed as q = kiA. | Principle | |
| Deep drains | High-permeability subsurface systems used to intercept, collect, and convey groundwater to control lateral flow, relieve pore pressure, or control seepage. | Solution | |
| Deep foundations | A foundation support system used where weak or variable soils require loads to be transferred to competent strata. Distinguished from ground improvement because the elements do not rely on the interaction with soil as the primary means of support. | Solution | |
| Deep Mix Method (DMM) | A broad term used for a family of deep mixing techniques and equipment; often used interchangeably with DSM and soil mixing. | Acronym: DMM. See also soil mixing or DSM. | Sub-Technology |
| Deep soil mixing (DSM) | Soil mixing performed at depths greater than 6 m below ground surface; used for geotechnical, environmental, or geoenvironmental applications. | Acronym: DSM. See also DMM or soil mixing. | Sub-Technology |
| Defense | An end market involving military or defense-related facilities where site conditions, security, and regulatory requirements may affect project delivery. These project sites often require special clearances and unique training. | Related: federal, military facilities. | Industry |
| Degree of saturation | The percentage of void volume filled with water. | Symbol: S. | Property |
| Demolition | Controlled removal of structures to support remediation or redevelopment. | Solution | |
| Densification | A soil improvement outcome in which the soil structure becomes denser, often increasing strength and stiffness. Most often used to describe compaction processes for granular soils. | See also compaction. | Principle |
| Density | Mass per unit volume; used in soil fundamentals, slurry monitoring, and QC. | See also unit weight. | Property |
| Design coordination | Coordination between technical design and construction planning so that the selected solution can be built effectively. | Related: design-build, constructability review. | Construction or Design Term |
| Design-Build | A project delivery approach that integrates engineering and construction under a single contract. | Related: integrated design development, construction sequencing. | Solution |
| Dewatering | Removal or control of groundwater to support excavation, construction, or seepage-control objectives. | Related: groundwater control, deep drains. | Solution |
| Diaphragm wall | A structural wall constructed using a slurry-supported excavation method where slurry is replaced by reinforced concrete; distinguished from the unreinforced slurry trench wall types referred to as "slurry trenching". | See also slurry wall. | Technology |
| Dredging | Removal, relocation, or management of sediments from under a water column in wetlands, shorelines, marine, or near-shore environments. | Technology | |
| Dry mixing | Soil mixing where the reagent is introduced in dry/powdered form, either at the surface or through the mixing shaft. Best applied to soft, high moisture soils. | See also soil mixing. | Sub-Technology |
| Earth retention | Systems used to support soil and groundwater during excavations or grade changes. | Solution | |
| Effective porosity | The interconnected pore space available to groundwater flow; it may be much lower than total porosity in clay and rock. Used in discussions of groundwater transport and seepage. | Property | |
| Energy, Oil & Gas | Project sites or clients engaged in energy production, including upstream and downstream facilities. | Related: energy production, upstream, downstream, oil and gas. | Industry |
| Engineered outlet | A deep drain component used to improve long-term performance. | Construction or Design Term | |
| Environmental remediation | Methods for removing, treating, containing, isolating, or stabilizing contaminants in soil, sediment, and groundwater. | Expertise | |
| Equipotential line | A line in a flownet with the same total hydraulic head at any point on the line. These lines are perpendicular to flow lines. | Principle | |
| Ex situ soil mixing | Soil mixing performed outside the original soil location. | See also soil mixing. | Sub-Technology |
| Excavation & removal | Methods used to physically remove contaminated or unsuitable soil and sediment from a site. | Solution | |
| Expertise | Professional and technical disciplines or problem domains, such as environmental remediation, groundwater control, ground improvement, foundations, marine services, and preconstruction support. | Sorting Category | |
| Federal | Government-controlled or government-funded project sites where construction requirements may be driven by public ownership, mission needs, and regulatory obligations. | Related: government agencies, public owner, defense. | Sub-Industry |
| Ferrous sulfate | An iron salt reagent used in in-situ treatment of heavy metals and chromium. | Material | |
| Filter media | Material that can be included in a deep drain to improve long-term performance. | Material | |
| Flow line | A line in a flownet representing the direction of groundwater flow. These lines are perpendicular to equipotential lines. | Principle | |
| Flowable fill | A material containing one or more cementitious components that can be placed into a hole after soil has been removed. | Material | |
| Flownet | A graphical map of groundwater energy distribution used to solve two-dimensional groundwater flow problems. Can be used to calculate flow, pore pressure, and exit gradient. | Principle | |
| Fly ash | A coal combustion residual material that is a fine, glass-like powder that is produced in the process of burning coal. It is a common supplementary material for cementitious mixes. | Material | |
| Foundations & shoring | Systems used to support excavations and structures in difficult ground or groundwater conditions with elements that do not rely heavily on the soil. | Expertise | |
| Funnel and Gate | A passive in-situ groundwater collection and treatment system that combines cutoff walls with permeable reactive or ad- / absorptive barriers. | Sub-Solution | |
| Funnel wall | The low-permeability cutoff wall component of a funnel-and-gate system that intercepts and directs groundwater flow toward the gate. | Sub-Solution | |
| Gate wall | The high-permeability treatment zone in a funnel-and-gate system where contaminants are treated or removed as groundwater flows through reactive media. | Sub-Solution | |
| Geoenvironmental contractor | A specialty contractor focused on solving complex subsurface challenges involving geotechnical and environmental construction. | Construction or Design Term | |
| Grab sample | A sample of freshly mixed soil material collected from the field for casting and later laboratory testing. Common for soil mixing, jet grouting, and slurry trenching projects. | Construction or Design Term | |
| Gradient | The slope that defines water flow from areas of higher mechnical energy (elevation) to areas of lower energy, defines as the head difference divided by the length. | See also hydraulic gradient. | Property |
| Grain size distribution | The particle size distribution of soil or backfill, used in assessing blending, packing, permeability, and suitability. | Acronym: GSD | Property |
| Ground improvement | Application of construction means and methods to improve the properties of soil. Ground improvement can be accomplished using one or more of the following principles: removal or control of water, particle rearrangement, additives, or system behavior. | Expertise | |
| Ground modification | Neutral term for alteration of ground conditions. Use carefully where improvement is not guaranteed. | See also ground improvement | Expertise |
| Groundwater control | Techniques used to manage subsurface water by containing, collecting, or redirecting flow. | Expertise | |
| Groundwater plume | Impacted groundwater that is carrying contaminants. | Construction or Design Term | |
| Grout curtain | The final product often associated with pressure grouting beneath dams. | Sub-Solution | |
| Grout | A fluid mixture, typically cementitious materials mixed with water and additives, injected into the subsurface during grouting. | Material | |
| Grouting | Injection of a liquid material, or grout, into voids in soil or rock to improve subsurface characteristics. | Solution | |
| Habitat restoration | Methods to re-establish habitats damaged by contamination or human impacts. | Solution | |
| Helical auger | A rotating auger installed on a drill rig used for auger excavation to remove soil in a controlled manner. | Construction or Design Term | |
| High-permeability wall | A vertical element designed to collect or direct groundwater, often deployed downgradient of contamination or as a drain. Someimes also referred to as a cutoff or barrier wall though that is counterintuitive. | Solution | |
| High-pressure fluid stream | The pressurized jet used in jet grouting to erode or mix soil with grout to create soil-cement elements. | Related: jet grouting, grout jet. | Construction or Design Term |
| Horizontal piping system | Perforated or collection piping installed in a drain or trench to convey groundwater. | Related: perforated pipe, outlet, deep drain. | Construction or Design Term |
| Hydraulic barrier wall | A vertical barrier used to slow, stop, or redirect groundwater movement across a site boundary or flow path. | Related: cutoff wall, vertical barrier, slurry wall. | Sub-Solution |
| Hydraulic conductivity | A property governing water flow through soil or particulate materials; also called coefficient of permeability. | Property | |
| Hydraulic gradient | The gradient term in Darcy’s law that describes head loss per length of flow path. | Symbol: i. See also gradient. | Property |
| Hydrostatic pressure | The force exerted by a fluid (at rest) on an object or surface that is due to gravity driving the fluid pressure. | Property | |
| In situ chemical oxidation | An in-situ treatment method that uses oxidizing agents to chemically transform contaminants in the ground. | Acronym: ISCO | Solution |
| In situ chemical reduction | An in-situ treatment method that uses reducing agents to chemically transform contaminants in the ground. | Acronym: ISCR | Solution |
| In situ soil mixing | Soil mixing performed in place, often using augers or cutting tools where reagents are added to create a composite material with improved properties relative to the soils alone. | Acronym: ISSM. See also soil mixing. | Technology |
| In Situ Stabilization/Solidification | A remediation technique that mixes reagents directly into soil using mechanical mixing methods to create a soil-reagent composite with enhanced properties. | Acronym.: ISS. See also stabilization and solidification. | Solution |
| In Situ Thermal Treatment | Treatment performed in place using heat-based methods to remove or mobilize contaminants in soil. | Related: steam enhanced extraction, thermal treatment. | Solution |
| Industries | End markets served, each with its own regulatory environment, risk profile, performance criteria, and project drivers. | Sorting Category | |
| Infrastructure | Transportation, water, and public works systems that are publicly funded., | Related: transportation, water systems, public works. | Industry |
| In-situ treatment | Remediation of contaminated soils and groundwater without excavation, using soil mixing to deliver oxidizing or reducing agents. | Solution | |
| Interlocking steel sheets | Steel sheets driven into the ground to form a continuous sheet pile wall. | Sub-Technology | |
| In-water capping | Placement of engineered cover systems over contaminated sediments under a water column; sand and armored caps are common applications. | Technology | |
| In-water soil mixing | Soil mixing performed on soils or sediments in place beneath a water column, commonly using barge-mounted soil mixing equipment. | Technology | |
| Jet grouting | An in situ process using high-pressure jets to inject additives and mix or erode soil, creating solidified soil-grout columns. The technique is a bridge between soil mixing and grouting. | Technology | |
| Landfill | Containment facilities used for long-term or permanent management of various waste streams | Related: waste containment, disposal facility. | Industry |
| Large diameter auger | A single large auger that can refer to augers used for soil mixing or excavation. | Acronym: LDA. | Construction or Design Term |
| Lateral earth support | Systems used to retain soil around excavations or waterfront structures. | See also earth retention. | Principle |
| Lateral groundwater flow | Horizontal groundwater movement that cutoff walls, drains, and barrier systems are commonly designed to control. | Related: horizontal groundwater flow, groundwater control. | Principle |
| Leachability | The tendency of contaminants to leach from treated material. This property isrelevant to environmental soil mixing that evaluates contaminant release or mobility after treatment. ISS aims to lower leachability. | Property | |
| Levees and Dams | Water-retaining or flood-control infrastructure where seepage control, foundation support, or rehabilitation work may be required. | Related: dam rehabilitation, levee repair, seepage control. | Sub-Industry |
| Lime | A naturally occuring inorganic material composed of calcium oxides and hydroxides used as a binding additive; most commonly used for dry soil mixing. | Material | |
| Liquefaction potential | The susceptibility of loose granular soils below groundwater to lose effective shear strength during dynamic loading such as earthquake shaking. | Construction or Design Term | |
| Low-permeability cutoff wall | A cutoff wall intended to slow or "cut off" groundwater flow, often with environmental containment or dewatering objectives. | Sub-Solution | |
| Manufactured gas plants | Former manufactured gas plant sites where soil and groundwater contamination from historical gas-production processes may require remediation. | Acronym: MGP. Related: manufactured gas plant. | Sub-Industry |
| Manufacturing | Industrial facilities where products are produced and where work may be for new construction or demolition and remediation for closures. | Related: industrial facilities, facility closure. | Industry |
| Marine services | Construction and remediation activities performed in rivers, harbors, waterfront environments, or areas involving soils or sediments in or near waterways. | Expertise | |
| Mechanical modification | Ground improvement principles involving rearrangement of soil or water particles. | Includes compaction and related approaches. | Principle |
| Mining | Physical extraction of earth to obtain coal, metals, or minerals, with needs that can include tailings management, legacy contamination, or excavation support. | Related: mine tailings, coal, metals, minerals. | Industry |
| Mixing energy | The amount of mechanical effort applied to blend soil and additives; relates to final strength and properties. | Related to BRN and homogeneity in soil mixing applications. | Property |
| Modification by additives | A ground improvement principle involving addition of binders, chemicals, or other reagents to change soil properties. | Principle | |
| Modification by inclusions or confinement | A ground improvement principle using rigid or flexible inclusions or confinement to modify system behavior. | Principle | |
| Multi-auger mixing | Soil mixing using multiple auger shafts, often with overlapping patterns to create a wall or continuous treated zone. | See also soil mixing, DSM, or DMM. | Sub-Technology |
| Near-surface soil mixing | Very shallow soil mixing, typically less than 0.6 m below the ground surface. Aka shallow soil mixing. | Sub-Technology | |
| Overlapping columns / panels | An arrangement where adjacent mixed or grouted elements overlap to create continuous coverage or a continuous wall. | Construction or Design Term | |
| Oxidizing agents | Reagents used in in-situ treatment to aid chemical oxidation of contaminants. Common oxidizers used in soil remediation include potassium permanganate or sodium persulfate. | Material | |
| Perforated pipe | A component that can be included in deep drains to improve long-term drainage performance. | Construction or Design Term | |
| Permeable adsorption/absorption barrier | A permeable barrier with media in the wall that sorb contaminants as groundwater flows through. | Acronym: PAB | Sub-Solution |
| Permeable media | Free-draining material placed in a trench, drain, or treatment zone to allow and encourage groundwater flow through the constructed element. | Related: filter media, aggregate, reactive media. | Material |
| Permeable reactive barrier | A permeable barrier with media in the wall that react with contaminants as groundwater flows through. | Acronym: PRB | Sub-Solution |
| pH | A chemical property referring to the potential of hydrogen which is used to meausre and represent the concentration of hydrogen ions in solution. The property describes whether the material is acidic, neutral or basic. | Property | |
| Pilot program / test | A field-scale evaluation, when feasible, used to verify bench-scale results under field conditions before full production. This activity is often used to support design and solution selection and is performed under a separate mobilization from full scale. | Construction or Design Term | |
| Pipe grouting | Grouting methods used to abandon, seal, or stabilize buried pipelines and conduits. | See also void grouting. | Solution |
| Piping | Erosion caused by seepage forces as groundwater exits soil. | Principle | |
| Polymer slurry | A slurry made with polymers, including naturally occurring or synthetic types, used as a slurry trench support medium in high permeability applications. | Material | |
| Polymer trenching | Trench excavation supported by polymer slurries, often used where the resulting trench needs to be high permeability rather than a low-permeability cutoff wall. | Technology | |
| Polymer | Large complex molecules made of smaller, repeating units called monomers. | Material | |
| Pore water pressure | Water pressure in soil pores; can be calculated from hydraulic head and unit weight of water. | Symbol often u. | Property |
| Porosity | Volume of voids divided by total volume; porosity values range from 0 to 1.0. | Symbol: n. | Property |
| Portland cement | A fine, hydraulic powder manufactured by heating limestone and clay minerals in a kiln to produce clinker, which is then ground and mixed with gypsum. This is the most common cementitious reagent or binder used in soil mixing, grouting, and self-hardening slurry systems. | Acronym: OPC = ordinary Portland cement; PC = Portland cement. | Material |
| Potassium permanganate | An oxidizing reagent used in in-situ treatment. | Material | |
| Preconstruction services | Early-stage contractor involvement used to address constructability and support project planning through studies, reviews, and pilot programs. | Expertise | |
| Pressure grouting | A common grouting approach for dam grouting and pipe grouting wherein grout is pumped into existing voids within soil or rock. | Sub-Technology | |
| Process controls | QC documentation and monitoring procedures used to track reagent slurry or grout production, delivery, and distribution during various construction processes. These controls provide real-time quality verification to promote end products that meet ultimate QC goals. | Construction or Design Term | |
| Quality assurance | Owner or engineer led efforts to verify or supplement QC. | Construction or Design Term | |
| Quality control | Contractor led testing and documentation used to verify that construction input materials and mixed products are consistent with the design or bench-scale basis. | Acronym: QC. | Construction or Design Term |
| Reactive gate | The permeable treatment portion of a funnel-and-gate system where groundwater passes through media that reacts with contaminants. | Related: gate wall, permeable reactive barrier. | Sub-Solution |
| Reactive media | Media in a PRB, gate, or soil mixing that interact with groundwater contaminants to promote passive treatment. | Material | |
| Reagent / additive | A material introduced to soil, typically by dry addition or as slurry/grout, to achieve various target property improvements. Target property improvements are typically reduced permeability, increased strength, and/or reduced leachability. | Material | |
| Reagent slurry or grout | A water-based slurry carrying reagents. | Construction or Design Term | |
| Reducing agents | Reagents used in in-situ treatment to aid chemical reduction of contaminants. The most common reducing agent used in environmental remediation is zero valent iron (ZVI). | Material | |
| Remedial excavation | Targeted removal of contaminated or unsuitable soils, often using traditional earthwork or large-diameter augers. | Solution | |
| Restoration | Final work to return a site to its intended condition after remediation or construction, such as backfill, grading, or grassing. | Related: site restoration, backfill, grassing. | Construction or Design Term |
| Rigid inclusions | Ground improvement elements that interact with surrounding soils to create a soil-element composite capable of supporting structural loads. | Solution | |
| Rotary tool mixing | Shallow or moderate depth soil mixing using rotary blending tools, paddles, stems, blades, or drums mounted to equipment. Typically used for mixing to depths of 15 to 20 feet. | Sub-Technology | |
| Secant pile walls | Retaining or cutoff walls constructed of interlocking concrete piles. | Technology | |
| Sediments | Soils or deposits under or near water that may require dredging, capping, stabilization, or remediation. | Related: contaminated sediments, dredging, in-water capping. | Sub-Industry |
| Seepage force | Force exerted on soil particles by flowing water; relates to hydraulic gradient and unit weight of water. Important consideration for piping risk. | Property | |
| Seepage velocity | Velocity of water moving through interconnected soil pores; greater than Darcy velocity because water does not flow through soil solids. This property is tied to effective porosity. | Property | |
| Seepage | Subsurface water movement controlled by groundwater control methods, cutoff walls, and deep drains. | Principle | |
| Selective dismantling | A demolition method referenced as a common approach for controlled removal. | Sub-Technology | |
| Self-hardening slurry | A slurry that serves as the excavation support and then sets/hardens in place to form the completed wall material. These slurries typically consist of ordinary portland cement, slag, bentonite, and water though other mixtures are used too. | Technology | |
| Shallow soil mixing | Soil mixing performed below near surface methods but above deep soil mixing depths; generally in the range of 0.6 m to 6 m below ground surface. | Acronym: SSM. | Sub-Technology |
| Shear strength | A soil property describing resistance to failure under shear stresses; ground improvement may increase it through densification or cementing components. Related to unconfined compressive strength through Mohr's circle. | Property | |
| Shear walls | Ground improvement walls installed to prevent slope movement due to loading above the slope or unloading below the slope. Commonly installed via soil mixing, used for slope stabilization. | Solution | |
| Sheetpiling | Installation of interlocking steel sheets to retain soil and water or create continuous walls for excavation support, groundwater control, or waterfront structures. | Technology | |
| Shoreline dredging | Dredging performed from the shoreline to remove or manage sediment near the water edge. | Related: shoreline excavation, nearshore dredging. | Sub-Technology |
| Shrink/swell behavior | Volume change behavior of expansive soils or hardened slurries, especially those involving smectitic clays. The behavior is in response to wetting and drying cycles. | Property | |
| Site preparation | Initial field work needed to ready a project site for remediation or construction, including access, controls, and support activities. | Related: mobilization, site controls. | Construction or Design Term |
| Slag | Granulated ground blast furnace slag, used with cement in some CB/SCCB and soil mixing mixtures to improve target properties. | Acronym: GGBFS. See also ground slag or blast furnace slag. | Material |
| Slag-cement-bentonite | A self-hardening slurry mixture made with slag and cement. | Acronym: SCCB. | Material |
| Slope stability | Principles of slope movement, typically discussed in terms of ways to improve slope stability through earth retention or shear walls that resist lateral movement of slopes during loading or unloading. | Solution | |
| Slump | A measure of workability and viscosity for backfill or soil-reagent mixtures, commonly measured using a slump cone. | Property | |
| Slurry head | The head or level of slurry used to maintain excavation stability during trenching. | Define with trench stability. | Construction or Design Term |
| Slurry trench | A vertical underground feature installed using slurry to support the excavation. Slurry trench or slurry trenching generally refers to installations that are not constructed in panels, are backfilled with soil or self-hardening slurries, and do not include concrete or reinforcing cages. | Technology | |
| Slurry trenching | A method of installing deep, narrow subsurface structures without conventional excavation support or dewatering by using slurry to balance lateral earth pressure. | See also slurry trench. | Technology |
| Slurry wall | A vertical underground feature installed using slurry to support the excavation. Slurry wall generally refers to installations that are constructed in panels and are backfilled with concrete and reinforcing cages. | See also diaphragm wall. | Technology |
| Sodium persulfate | An oxidizing reagent used in in-situ treatment. This oxidizer is often added with cement because cement catalyzes the oxidation reaction. | Material | |
| Soil mixed wall (SMW) | A linear soil mixing product originally associated with proprietary techniques using overlapping modified auger shafts; the term has fallen out of common use. | Acronym: SMW. | Sub-Technology |
| Soil mixing | A ground improvement technique that introduces additives into the subsurface while mixing them with the in situ soil to improve physical, engineering, or chemical characteristics. | Technology | |
| Soil-bentonite | A slurry trench cutoff wall typically excavated under bentonite-water slurry and backfilled with soil blended with bentonite to reduce permeability. | Acronym: SB. | Sub-Technology |
| Soil-cement columns / panels | Discrete or overlapping soil-grout elements created by jet grouting or soil mixing to form improved columns, panels, or treatment zones. | Related: jet grouting, soil mixing, soilcrete. | Construction or Design Term |
| Soil-cement-bentonite | A soil-bentonite style wall with added cementitious component where additional shear strength is needed. | Acronym: SCB. | Sub-Technology |
| Soilcrete | A common term for soil blended with cementitious reagents. The resulting mixture is like concrete in that its cement mixed with aggregates, but different because the aggregate includes a variety of soil types including clays and silts. | Construction or Design Term | |
| Soil-reagent composite | The improved material created by mixing in situ soil and reagents to achieve improved properties relative to the original soil. | Construction or Design Term | |
| Soldier pile wall | A conventional earth retention solution involving driven or drilled H-piles with wood lagging installed between the piles. | Technology | |
| Solidification | Methods that reduce contaminant mobility by locking them in a low-permeability monolith. Often used interchangably with stabilization though this is a different process to accomplish a similar objective. In many applications both are occuring simultaneously. | Solution | |
| Solutions | Defined outcomes for clients, such as cutoff walls, in situ treatment, bearing capacity improvement, slope stability, or habitat restoration, rather than a single construction method. | Sorting Category | |
| Specific gravity | A defined ratio for solids used in phase relationships that relates the density of the subject material to the density of water. | Property | |
| Spoils management | Handling, staging, treatment, reuse, or disposal of excavated or mixed materials generated during construction. | Related: spoils, reusable backfill, material handling. | Construction or Design Term |
| Stabilization | Methods that reduce contaminant mobility by chemically altering contaminants or binding them to soil. Often used interchangably with solidification though this is a different process to accomplish a similar objective. In many applications both are occuring simultaneously. | Solution | |
| Steam enhanced extraction | A thermal treatment method mixed with soil mixing used to remove volatile and semi-volatile contaminants from soil. | Solution | |
| Steam injection | Introduction of steam into soil to heat the subsurface and support removal of volatile or semi-volatile contaminants. | Related: steam enhanced extraction, thermal treatment. | Sub-Technology |
| Steel reinforcement | Steel placed in grout, concrete, piles, or walls to provide structural capacity beyond the cementitious material alone. | Related: reinforcing cage, H-pile, beam reinforcement. | Material |
| Superfund Site | A contaminated site addressed under a formal, federally funded cleanup program. | Related: hazardous waste site, cleanup site. | Sub-Industry |
| Surface compaction | A shallow compaction approach using surface equipment to apply mechanical energy that dissipates with depth. | Also called shallow compaction in context. | Technology |
| Technical evaluation | A planning or consulting activity used to assess site conditions, technology options, and practical construction considerations. | Related: consulting, preconstruction services. | Construction or Design Term |
| Technologies | Construction methods, tools, and processes used to physically perform work, such as soil mixing, jet grouting, slurry trenching, dredging, or auger cast piles. | Sorting Category | |
| Test section | A full-scale evaluation performed immediately before or near the start of work to verify reagent type, addition rate, or construction method. This is similar to a pilot study / test but different in that it is performed under the same mobilization as the planned full scope work. | Construction or Design Term | |
| Tieback | A support element that can be used to externally brace earth retention systems. | Construction or Design Term | |
| Traditional earthwork | Excavation, grading, and material handling activities that support construction and remediation. | Technology | |
| Transportation and disposal | Management of excavated or impacted materials by hauling them off site and disposing of them in accordance with project requirements. | Related: T&D, material disposal, off-site disposal. | Construction or Design Term |
| Treatment pattern | The layout or arrangement of mixed elements such as columns, panels, or cells used to achieve the project objective. | Construction or Design Term | |
| Trench stability | The ability of a slurry-supported trench to remain open without collapse during excavation. | Construction or Design Term | |
| Turbidity control | An environmental control used in dredging operations to manage water clarity and compliance impacts. | Construction or Design Term | |
| Unconfined compressive strength | A common strength measure used to evaluate soil-reagent mixtures. By definition, the UCS is 2X the shear strength. | Acronym: UCS. | Property |
| Underpinning | Structural support application wherein elements are installed beneath existing structures. This is commonly performed using grouting or jet grouting, especially in urban or restricted-access areas. | Construction or Design Term | |
| Unit weight | Weight per unit volume; used with density and groundwater calculations in geotechnical analysis. Related to but different from density and specific gravity. | Property | |
| Uplift | Bouyancy forces that can act upon buried structures. | Construction or Design Term | |
| Utilities | Companies that deliver power, water, or communications and may have needs at operating and legacy facilities. | Related: power, water, communications. | Industry |
| Utility relocation | Moving or replacing utility lines to allow remediation or construction work to proceed safely and as designed. | Related: water line, sanitary sewer, gas pipeline. | Construction or Design Term |
| Vapor extraction | Removal of contaminant vapors from soil during thermal treatment or similar remediation processes. | Related: steam enhanced extraction, volatile contaminants. | Sub-Technology |
| Variability | Natural variation in physical and engineering properties of soils that can affect structure performance; ground improvement may make performance more uniform. | Principle | |
| Vertical barrier | A vertical subsurface structure used to stop or slow groundwater flow. In practice, this is used interchangeably with cutoff wall and barrier wall though the terms can have differences | Solution | |
| Vibrated beam | Cutoff wall construction using a beam inserted with vibratory methods wherein the cavity created from the beam is filled with slurry or grout. | Technology | |
| Vibratory hammer | Equipment typically used to drive elements, e.g. sheetpiles or piles, into the ground using vibration. | Construction or Design Term | |
| Void filling | Filling of subsurface voids, abandoned pipes, tunnels, mine shafts, or similar spaces using grout. | Sub-Solution | |
| Void ratio | Volume of voids divided by volume of solids; used as an indicator of soil density/compactness. | Symbol: e. | Property |
| Water content / moisture content | The ratio of water mass to solids mass in a soil, important for soil behavior and mix design. | Property | |
| Water-to-solids ratio | A ratio of water to solids, by weight; lower W:S ratios generally produce higher strength and lower permeability, while higher ratios may aid homogeneity and mixing efficiency in soil mixing applications. | Acronym: W:S. | Property |
| Wet mixing | Soil mixing where the reagent is introduced in a fluid grout or slurry and pumped into and spread through the soil while mixing. | Sub-Technology | |
| Wetland remediation | Methods used to re-establish or rehabilitate sensitive wetland ecosystems damaged by human interactions. | Solution | |
| Wetlands | Sensitive wetland ecosystems that may require rehabilitation, re-establishment, or construction methods that reduce impacts to aquatic environments. | Related: wetland remediation, wetland creation. | Sub-Industry |
| Workability | The ability of a mixed material to be blended, placed, or flow sufficiently for construction; often assessed using slump or visual indicators. This is qualitative, not quantitative term. | Construction or Design Term | |
| Zero-valent iron | A reducing material used in in-situ treatment and often in funnel-and-gate treatment zones. A common additive for treating chlorinated solvent contaminants. | Acronym: ZVI. | Material |