Soil and Foundation Basics – ISO Geotechnical Principles Explained
Learn how soil properties affect foundations and how geotechnical principles relate to foundation, pile, and concrete calculations.
Geotechnical standards describe how soil properties influence foundation design. This page explains why the same building needs different foundations on different soils, how standards describe soil behavior and classification, and how soil assumptions connect to practical foundation calculations. This is an educational resource that bridges soil mechanics concepts with construction calculations.
What Geotechnical Standards Cover
Soil types (sand, clay, gravel, rock)
The basic classification of soils and how different types behave differently under load. Sand drains well but can shift. Clay holds water and can expand or contract. Gravel is strong and stable. Rock provides the strongest foundation.
Bearing capacity concepts
Bearing capacity is the soil's ability to support loads without failure. Strong soils can support more load per unit area. Standards define how to determine and use bearing capacity values.
Settlement and deformation
All soils compress under load—this is settlement. Some soils settle more than others. Standards provide guidance on acceptable settlement limits.
Groundwater influence
Water in the ground affects soil behavior. High groundwater can reduce soil strength, cause frost heave, and require drainage systems.
Safety factors and assumptions
Standards define safety factors to account for uncertainty in soil properties. These factors ensure foundations are designed conservatively.
Standards define HOW soils are classified and tested, not just numerical values.
In Russian practice, field teams expand on these ideas using the SP & SNiP Foundations hub.
How Soil Affects Foundations
Weak soil → larger foundations
Weak soils cannot support much load per unit area, so foundations must be larger (wider, deeper) to spread the load over more soil area.
Compressible soil → settlement risk
Soils that compress easily (like soft clay) will settle more under load, requiring deeper foundations or special design considerations.
Groundwater → drainage and design changes
High groundwater levels can reduce soil strength, require waterproofing, and may need drainage systems or dewatering during construction.
Piles used when shallow foundations are insufficient
When soil near the surface is too weak, piles transfer loads to deeper, stronger soil layers or bedrock.
Calculations in Early-Stage Practice
Before detailed soil reports, users commonly estimate:
- Foundation geometry: Estimating foundation dimensions based on building loads and assumed soil conditions
- Concrete volume: Calculating concrete needed for foundations based on estimated dimensions
- Pile quantity and size: Estimating number and size of piles for preliminary design
- Reinforcement estimates: Calculating approximate rebar quantities for foundation elements
Final design always requires geotechnical investigation.
Related Learn Articles
- Estimation vs Engineering Design – What Calculators Can and Cannot Do
Understand the difference between early estimates and full engineering design so you can use calculators responsibly.
- Foundation Types Explained: Strip, Slab, and Pile Foundations
Learn how strip, slab, and pile foundations share loads, when each option fits, and why geotechnical input matters.
- Soil Basics for Foundations
Understand how soil types, bearing capacity, and groundwater inform Russian foundation choices.
- Why Soil Investigation Matters for Foundations
Understand why soil assumptions are risky, how bearing capacity and settlement vary, and when testing becomes mandatory.
⚠️ Critical Disclaimer
- •Calculators are for estimation only.
- •Soil properties cannot be assumed without proper geotechnical testing.
- •Always consult qualified geotechnical engineers and local building regulations.
- •Final foundation design requires site-specific soil investigation and professional engineering.
- •This page is an educational resource, not a substitute for geotechnical engineering services.
Frequently Asked Questions
What is this standard used for?
This standard provides guidelines and requirements for specific calculations and design procedures in its field of application.
How do I apply this standard?
This page provides educational context about the standard. For actual design work, consult the official standard documents and qualified engineers. Our calculators can help with preliminary estimations, but they are not a substitute for professional design.