Geotechnical Design Services | Fen Zemin & İnşaat
Geotechnical Design Services | Fen Zemin & İnşaat
Fen Zemin & İnşaat provides geotechnical design services for deep foundations, excavation support systems, retaining structures and ground improvement applications.
Our design work may include bored pile foundations, bored pile retaining walls, ground anchors, soil nail and shotcrete systems, micropiles, jet grouting and dynamic compaction.
A geotechnical design should not be based only on calculations.
Ground conditions, structural loads, groundwater, neighbouring structures, excavation geometry, available working space, equipment access and construction sequence all affect whether a proposed solution can be safely and practically executed.
For this reason, Fen Zemin & İnşaat evaluates geotechnical design together with field constructability.
What Is Geotechnical Design?
Geotechnical design is the engineering process used to determine how foundations, retaining systems and ground improvement methods should interact with the soil or rock at a specific project site.
The process may include evaluation of:
- ground investigation data,
- soil and rock parameters,
- groundwater conditions,
- structural loads,
- excavation depth,
- allowable settlement,
- lateral deformation,
- neighbouring structures,
- construction sequence.
The objective is to develop a system that satisfies the technical requirements of the project and can also be constructed under the actual site conditions.
What Geotechnical Systems Do We Design?
Depending on the project scope, Fen Zemin & İnşaat may provide design services for:
- bored pile foundations,
- bored pile retaining walls,
- anchored excavation support systems,
- soil nail and shotcrete systems,
- internally braced excavation support,
- micropile foundations,
- foundation strengthening,
- jet grout ground improvement,
- dynamic compaction,
- related foundation and retaining applications.
Each system responds to a different engineering problem.
The method should therefore be selected after the ground conditions and project requirements are understood.
Excavation Support Design
Deep excavation changes the stress conditions in the surrounding ground.
As soil is removed, the excavation support system must resist lateral earth pressures and control movement.
Excavation support design may consider:
- excavation depth,
- soil profile,
- groundwater,
- neighbouring buildings,
- roads and utilities,
- allowable wall movement,
- construction stages,
- available support systems.
The retaining system may consist of bored piles, ground anchors, soil nails, shotcrete, internal struts or a combination of these methods.
Bored Pile Retaining Wall Design
Bored piles may be used as vertical elements in excavation support systems.
The design may include evaluation of:
- pile diameter,
- pile spacing,
- pile length,
- reinforcement,
- embedment depth,
- lateral soil pressures,
- anchor or strut levels,
- deformation behaviour.
The wall should be evaluated together with the excavation sequence and any supporting elements.
A bored pile retaining wall is not designed independently from the surrounding ground.
Ground Anchor Design
Prestressed ground anchors may be used to provide lateral support to retaining systems.
Anchor design may include:
- anchor inclination,
- design load,
- free length,
- bond length,
- horizontal spacing,
- vertical spacing,
- lock-off load,
- testing requirements.
The bond zone should be positioned in ground capable of transferring the required load.
Neighbouring foundations, utilities, property boundaries and available drilling geometry must also be considered.
Soil Nail and Shotcrete Design
Soil nail systems reinforce the existing ground mass with passive steel elements installed at defined angles and spacing.
Shotcrete is commonly used as the facing system.
Design considerations may include:
- excavation stages,
- soil nail length,
- nail inclination,
- horizontal and vertical spacing,
- pullout resistance,
- facing thickness,
- reinforcement,
- drainage.
Soil nailing is generally carried out in stages as excavation progresses.
For this reason, the construction sequence is an integral part of the design.
Internal Bracing Systems
Where ground anchors cannot be installed because of neighbouring structures, property boundaries or other restrictions, internal bracing may be considered.
This may include steel struts or other temporary structural support systems.
The design must account for:
- excavation geometry,
- retaining-wall loads,
- strut levels,
- connection details,
- construction access,
- interference with permanent works.
The support system should be coordinated with the excavation and structural construction programme.
Deep Foundation Design
Deep foundations transfer structural loads to deeper soil or rock layers where near-surface ground cannot provide adequate support or settlement performance.
Depending on the project, deep foundation design may include bored piles or micropiles.
The design may evaluate:
- axial compression,
- uplift,
- lateral loading,
- settlement,
- pile-soil interaction,
- group effects,
- structural pile requirements.
The appropriate foundation system depends on both structural loading and geotechnical conditions.
Bored Pile Foundation Design
Bored pile foundation design may involve selection of:
- pile diameter,
- pile length,
- pile spacing,
- founding level,
- reinforcement,
- pile group configuration.
The design should consider both geotechnical resistance and structural requirements.
Construction conditions are also important.
A theoretically suitable pile may be difficult to construct if the site cannot accommodate the required drilling rig, reinforcement cages or concrete operations.
Micropile Design
Micropiles can be particularly useful for foundation strengthening, underpinning and restricted-access projects.
Micropile design may include:
- pile diameter,
- pile length,
- steel load-carrying element,
- grout system,
- bond length,
- pile spacing,
- connection to the existing structure.
For strengthening projects, the interface between the new micropiles and the existing foundation is a critical part of the system.
Ground Improvement Design
Ground improvement is used to modify the engineering properties or behaviour of the existing ground.
Depending on the project, Fen Zemin & İnşaat may evaluate:
- jet grouting,
- dynamic compaction,
- related ground treatment methods.
The appropriate method depends on the ground profile, required performance and available working conditions.
FHWA guidance similarly treats ground improvement as a process involving method selection, design, performance criteria, construction, QA/QC and monitoring rather than as a single construction operation.
Jet Grout Design
Jet grouting creates soil-cement elements by mixing the in-situ ground with a cementitious binder.
Design considerations may include:
- treatment depth,
- column geometry,
- column arrangement,
- target properties,
- groundwater,
- overlap requirements,
- construction sequence.
Jet grout parameters should be selected according to actual soil conditions.
Column diameter should not be assumed solely from pressure or equipment capacity.
Dynamic Compaction Design
Dynamic compaction can be used to densify suitable granular soils and fills.
Design considerations may include:
- required treatment depth,
- tamper weight,
- drop height,
- grid spacing,
- number of blows,
- number of passes,
- verification testing.
The method also requires assessment of vibration and the effect on nearby structures or utilities.
What Information Is Required for Geotechnical Design?
The design process begins with reliable project information.
Where available, the following documents should be reviewed:
- ground investigation report,
- borehole logs,
- laboratory and field test results,
- groundwater information,
- architectural drawings,
- structural drawings,
- foundation loads,
- excavation sections,
- neighbouring structure information,
- site layout.
Incomplete or inconsistent input data can directly affect the reliability of the design.
How Is the Ground Investigation Report Used?
The ground investigation report provides information about the soil and rock profile beneath the site.
This information may include:
- layer thicknesses,
- soil classification,
- strength parameters,
- groundwater,
- field test results,
- laboratory test results.
These data are used to develop the geotechnical model required for design.
However, the investigation report should not be read independently from the actual project.
The same ground profile may require different solutions depending on structural loads, excavation depth and performance criteria.
Our Geotechnical Design Process
Fen Zemin & İnşaat follows a project-specific design process.
1. Review of Available Data
Ground investigation, architectural and structural information are reviewed.
2. Definition of the Engineering Problem
The project requirement is identified.
This may involve bearing capacity, settlement, excavation stability, lateral movement, ground improvement or foundation strengthening.
3. Selection of Alternative Systems
Technically feasible foundation, retaining or ground improvement methods are compared.
4. Geotechnical Analysis
The selected alternatives are analysed according to relevant design parameters and project requirements.
5. Constructability Review
The proposed system is reviewed against actual site constraints.
6. Design Development
Drawings, dimensions, levels and technical requirements are developed for the selected system.
7. Field Coordination
Where design and construction are both within the project scope, field conditions can be compared with design assumptions during execution.
Why Constructability Matters in Geotechnical Design
A design can be analytically correct but difficult or impossible to construct.
For example:
- a large bored piling rig may not fit onto the site,
- a ground anchor may extend into a neighbouring foundation,
- a micropile rig may have insufficient headroom,
- jet grout equipment may require more working area than is available,
- internal struts may obstruct permanent structural works.
These issues should be identified during design rather than after construction begins.
Fen Zemin & İnşaat’s field experience helps bring this constructability perspective into the design process.
Design and Construction Drawings
Geotechnical design drawings should clearly communicate the information required for field execution.
Depending on the system, drawings may include:
- pile layouts,
- sections,
- anchor levels,
- soil nail layouts,
- reinforcement details,
- jet grout layouts,
- foundation details,
- excavation stages.
Construction teams need information that can be interpreted directly on site.
For this reason, design documentation should be coordinated with field application requirements.
Design Revisions During Construction
Ground conditions cannot always be known perfectly before excavation or drilling begins.
If actual field conditions differ significantly from the assumptions used in design, the implications may need to be reviewed.
Examples may include:
- unexpected fill,
- different groundwater conditions,
- rock at a different depth,
- unidentified utilities,
- neighbouring foundation conflicts.
A design revision should not be made informally in the field without considering the engineering consequences.
The relevant data should first be reviewed and the design updated where necessary.
How Testing Contributes to Geotechnical Design
Testing and monitoring can provide important feedback on actual system performance.
Depending on the project, this may include:
- pile load testing,
- Pile Integrity Testing,
- anchor testing,
- inclinometer monitoring,
- ground improvement verification testing.
Testing results may be compared with design assumptions and acceptance criteria.
The appropriate test depends on the system being evaluated.
Geotechnical Design and Field Execution
Fen Zemin & İnşaat’s approach links engineering design with field execution.
This is particularly important in geotechnical construction because soil, groundwater and access conditions can directly influence the method used on site.
The objective is to avoid a disconnect between what is shown on the drawing and what can actually be built.
Geotechnical Design Cost
Geotechnical design cost depends on the complexity and scope of the project.
Factors may include:
- project size,
- excavation depth,
- foundation loads,
- number of design sections,
- ground variability,
- retaining-system complexity,
- ground improvement requirements,
- number of design alternatives,
- required drawings and calculations,
- revision requirements.
A simple foundation evaluation and a complex multi-stage deep excavation do not require the same level of engineering effort.
For this reason, design fees should be based on the actual scope rather than a generic project area.
How Does Fen Zemin & İnşaat Evaluate a Design Project?
The initial assessment starts with the available project information.
Where available, we review:
- ground investigation report,
- architectural project,
- structural project,
- foundation loads,
- excavation sections,
- neighbouring structures,
- site conditions.
The engineering problem is then defined and suitable methods are evaluated.
The objective is to develop a solution that is technically appropriate, constructible and consistent with the requirements of the project.
Geotechnical Design in Istanbul and Across Türkiye
Fen Zemin & İnşaat is based in Ümraniye, Istanbul.
Geotechnical design projects in Istanbul and other regions of Türkiye may be evaluated depending on technical scope, available project data and required engineering services.
Design services may be provided for residential, commercial, industrial, infrastructure, deep excavation, foundation and ground improvement projects.
Geotechnical Design Frequently Asked Questions
What is geotechnical design?
Geotechnical design is the engineering process used to determine how foundations, retaining systems and ground improvement methods should interact with the ground at a specific site.
What systems can Fen Zemin & İnşaat design?
Depending on project scope, design services may include bored pile foundations, bored pile retaining walls, ground anchors, soil nail and shotcrete systems, micropiles, jet grouting and dynamic compaction.
Is a ground investigation report required?
A reliable geotechnical design generally requires appropriate ground investigation data. The required level of investigation depends on the project and ground conditions.
Does Fen Zemin & İnşaat provide excavation support design?
Yes. Depending on project scope, excavation support systems including bored piles, ground anchors, soil nails, shotcrete and internal bracing can be evaluated.
Does Fen Zemin & İnşaat design deep foundations?
Yes. Bored pile and micropile foundation systems can be evaluated according to structural loads and ground conditions.
Does Fen Zemin & İnşaat design ground improvement systems?
Yes. Depending on the project, jet grouting, dynamic compaction and related ground improvement solutions may be evaluated.
Why is constructability important in geotechnical design?
A technically adequate system must also be practical to build. Site access, equipment dimensions, neighbouring structures, utilities and construction sequence may affect the final design.
Can the design change during construction?
If actual field conditions differ significantly from the design assumptions, engineering review and design revision may be required.
What information is required for a geotechnical design quotation?
Where available, the ground investigation report, architectural and structural drawings, foundation loads, excavation sections, project location and required scope should be provided.
Discuss Your Geotechnical Design Project with Fen Zemin & İnşaat
For deep foundations, excavation support, bored pile walls, ground anchors, micropiles or ground improvement design, you can share your available project information with Fen Zemin & İnşaat.
Where available, provide the ground investigation report, architectural and structural drawings, foundation loads and site information so that the engineering scope can be reviewed accurately.
Contact the Fen Zemin & İnşaat technical team to discuss your geotechnical design requirement