Geotechnical Design: Foundations & Piles Retaining Walls · Soft Soil Improvement · Slope Stability

1. Foundation and Pile Design (Foundation Design)

We design the foundation best suited to the soil conditions, loads and project budget, using SPT N-Value and lab test data from the soil investigation.

• Shallow Foundation Design — spread and combined footingsDesign of Spread Footings, Combined Footings and Mat Foundations for sites where the soil has sufficient bearing capacity. Bearing Capacity is calculated per Terzaghi, Meyerhof and Hansen, and Settlement is checked against acceptable limits.
• Pile Foundation Design — driven piles, bored piles, micropilesSelection of the most economical pile type (Driven Precast, Bored Pile, Micro Pile, Barrette), size and depth using actual SPT N-Value data. Ultimate Pile Capacity is calculated with the Static Formula and verified by PDA or Static Load Test.
• Pile Capacity Analysis — load capacity analysisAnalysis of single pile capacity and Group Effect, calculation of Negative Skin Friction in areas of ground settlement, and design of Pile Caps and Rafts for uniform load distribution.
• Settlement Analysis — settlement analysisCalculation of Immediate Settlement, Primary Consolidation Settlement and Secondary Compression using Cc, Cv and the Secondary Compression Index (Cα) from the Consolidation Test, predicting settlement time and final settlement magnitude.
• Lateral & Uplift Pile — uplift and lateral pilesPile design for solar farms, high-voltage transmission towers, sign poles and wind-loaded structures. Uplift capacity is calculated from skin friction, and lateral capacity by the Broms method or p-y curves, checking pile-head displacement, bending moment and tension reinforcement, with a proposed Uplift Test and Lateral Load Test plan.
• Machine Foundation — machine foundationsFoundation design for rotating machinery such as pumps, compressors and generators, and for impact machinery, following ACI 351.3R. The natural frequency of the foundation-soil system is analyzed to stay clear of the operating frequency, vibration amplitude is checked against manufacturer criteria, and the machine foundation is isolated from the building floor to reduce vibration transmission.

2. Retaining Wall and Earth Structure Design (Retaining Structure Design)

Design of all types of earth-pressure-resisting structures for temporary and permanent excavations in urban and confined sites — read more: Which retaining wall to choose? 7 types compared and Retaining walls under the Ministerial Regulation B.E. 2566 (2023): the 3 FS checks to pass

• Sheet Pile and Soldier Pile DesignDesign of steel Sheet Piles (U-type, Z-type) and Soldier Piles (H-Pile + Lagging) for temporary and permanent excavations. Earth Pressure is calculated per Rankine and Coulomb, with Anchor and Strut systems designed alongside.
• Diaphragm Wall DesignDesign of reinforced concrete walls cast in a trench (Slurry Wall) for very deep urban excavations — high stiffness, good watertightness and low deformation — analyzed by FEM (PLAXIS) with checks of impact on adjacent buildings.
• Gravity, Cantilever and Counterfort Retaining WallDesign of all types of concrete retaining walls to ACI 318 and EIT standards, checking Sliding, Overturning, Bearing Capacity and Settlement to pass every Failure Mode.
• Anchor and Strut SystemDesign of bracing (Strut) and tie-back (Ground Anchor / Tie-back) systems for deep excavations, calculating Prestress, Free Length, Bond Length and anchor Group Effect per BS 8081 and FHWA.
• Dewatering and adjacent-impact assessmentDesign of groundwater lowering systems so excavation can proceed in the dry, checking Basal Heave, Piping and water pressure beneath the excavation base, and assessing settlement of soil and adjacent buildings from dewatering and wall deformation, with instrumentation (Inclinometer, Piezometer, Settlement Point) and alarm levels specified for construction.
• Riverbank Protection — bank protection and waterfront wallsDesign of riverbank protection and waterfront walls to suit the soil profile, analyzing stability under Rapid Drawdown, water pressure behind the wall and toe erosion with Slope/W — read more: Preventing riverbank collapse: how to design a waterfront retaining wall

3. Soft Soil Improvement and Slope Stability Analysis (Ground Improvement & Slope Stability)

Solving soft soil problems in Central Thailand and coastal areas, with slope safety analysis using internationally standard software — read more: How many Ground Improvement methods are there? 8 soft soil methods summarized

• Preloading with PVD Design — temporary surcharge and Prefabricated Vertical DrainsDesign of the PVD Layout (spacing, pattern, depth) and Surcharge Height to accelerate soft soil consolidation, calculating the Time Rate of Consolidation with Barron's Solution and tracking progress with Settlement Plates and Piezometers.
• Deep Mixing (DCM) and Cement GroutingDesign of Deep Cement Mixing to strengthen soft soil under foundations or form a cutoff wall, specifying Cement Content, Water-Cement Ratio and Column Spacing, plus Grouting design to fill voids and cracks in soil and rock.
• Stone Column Design — stone columns and Vibro CompactionDesign of Stone Columns to improve soft soil under heavy loads such as roads, factories and water tanks, calculating the Bearing Capacity Improvement Factor, Settlement Reduction Factor and Drainage Effect.
• Slope Stability Analysis — with Slope/W and PLAXISStability analysis of slopes and embankments by the Bishop, Janbu and Morgenstern-Price methods in Slope/W (GeoStudio), calculating the Factor of Safety (FS) for both Drained and Undrained Conditions, and designing remedial measures when FS does not meet the criteria.
• Embankment and Earth Dam — embankments and seepageDesign of road embankments, levees and earth dams on soft soil, analyzing seepage with SEEP/W for the phreatic line, pore water pressure and Exit Gradient, together with Slope/W for the construction, normal operation and rapid drawdown conditions, and designing staged filling (Stage Construction) when the foundation soil lacks capacity.
• Slab-on-Grade — ground-supported slabs and warehouse floorsDesign of factory and warehouse floors for Selective Racks, forklifts and distributed loads following ACI 360R, using the Modulus of Subgrade Reaction (k) from a Plate Bearing Test and analyzing settlement of fill and soft soil to decide between a slab-on-grade and a pile-supported slab.

4. Foundation Assessment, Remediation and Consulting (Assessment & Consulting)

Solving pile and foundation problems found during construction or in service, plus specialist analysis before pile driving and heavy lifts begin.

• Pile Remedial — defective pile remediationFor piles with excessive eccentricity, piles that did not reach design level, broken piles, or piles failing the Seismic Integrity Test, we assess the remaining capacity and additional moment, then design the fix, such as additional piles, enlarged footings or tie beams — read more: What to do with off-center piles and Piles shorter than design
• Underpinning — strengthening existing foundations and extensionsDesign of Micro Piles under existing foundations per FHWA guidance for buildings that have settled or must carry additional load, and design of extension foundations structurally separated from the existing building to reduce differential settlement — read more: House extensions without settlement and cracks
• Seismic Site Class and LiquefactionSite classification per DPT 1301/1302-61 from investigation data, assessing the liquefaction potential of loose saturated sand layers and its effect on pile capacity — read more: Which soils risk liquefaction
• Wave Equation Analysis (GRLWEAP)Pile driving simulation before mobilization: selecting hammer size and drop height, estimating blows per penetration, and checking compressive/tensile driving stresses in the pile against material strength — used together with field PDA Test results.
• Crane Pad and Working PlatformChecking soil capacity under mobile crane outriggers and piling rig crawler tracks, specifying the crushed rock layer or mat thickness, and verifying soil capacity by Plate Bearing Test before heavy lifts.
• Design Review and Value EngineeringReview of calculation sheets and drawings for foundations, piles and earth-retaining systems, identifying risks and proposing cost-saving alternatives, such as adjusting pile type or length from actual soil data, while still meeting safety criteria.