CGCivil Geo Tools

Blog

Practical engineering resources with formulas, examples, assumptions, limitations, and clear internal links to related calculators.

8 min

How to Read a Proctor Curve: OMC, MDD, and Example

Read a Proctor moisture-density curve, identify OMC and MDD, check dry and wet sides, verify peak bracketing, and follow a worked dataset.

8 min

Standard vs Modified Proctor Test: Key Differences

Compare Standard and Modified Proctor tests by ASTM method, rammer, drop, layers, compactive effort, OMC, MDD, and field acceptance use.

11 min

Common Foundation Failure Modes

Foundation failure modes including bearing failure, settlement, sliding, overturning, uplift, scour, expansive soil movement, and construction defects.

11 min

Driven Piles vs. Drilled Shafts

Engineering comparison of driven piles and drilled shafts, including load transfer, applications, construction risks, testing, and limitations.

10 min

Eccentric Footing Loads, Kern Checks, and Partial Contact

How moments shift footing resultants, change corner pressure, and cause partial soil contact under uniaxial or biaxial loading.

12 min

Foundation Construction Inspection and Quality Control

Practical inspection and acceptance guide for shallow foundations, driven piles, drilled shafts, micropiles, and augered piles.

12 min

Foundation Design Workflow for Structural Engineers

A coordinated structural-geotechnical workflow from reactions and soil recommendations through footing pressure, settlement, strength, and construction documents.

11 min

Foundation Settlement: Total, Differential, and Angular Distortion

How immediate, consolidation, and secondary settlement affect foundations, and why differential movement often controls performance.

10 min

How Engineers Select a Foundation Type

A step-by-step foundation selection framework based on loads, ground conditions, settlement, groundwater, constructability, and project risk.

10 min

Mat and Raft Foundations: Applications and Limitations

When mat foundations are used, how they interact with soil, and why bearing pressure alone is not enough for design.

10 min

Micropiles and Helical Piles: Applications and Limitations

Practical comparison of micropiles and helical piles for underpinning, retrofit, uplift, restricted access, and new construction.

10 min

Spread Footings: Applications, Design Checks, and Limitations

Engineering guide to isolated spread footings, including bearing pressure, eccentricity, settlement, structural checks, and unsuitable conditions.

9 min

Strip, Combined, and Strap Footings

How continuous, combined, and strap footings distribute column and wall loads, with applications, pressure models, and design limitations.

11 min

Types of Foundations: Shallow and Deep Systems Explained

A practical guide to spread footings, strip footings, mats, driven piles, drilled shafts, micropiles, and other foundation systems.

9 min

Ultimate vs Allowable Bearing Capacity: Formula and Example

Compare ultimate, net ultimate, gross allowable, and net allowable bearing capacity with factor-of-safety formulas, settlement limits, and a worked footing example.

10 min

Undrained Shear Strength (Su): Meaning, Units, and Tests

Understand undrained shear strength Su for saturated clay, including units, total-stress use, unconfined compression, field vane and triaxial tests, and typical consistency ranges.

9 min

Axial Pile Capacity Example

Worked circular pile example combining average shaft resistance and toe resistance to calculate ultimate and allowable axial capacity.

9 min

Biaxial Footing Contact Pressure Example

Worked rectangular footing example calculating eccentricities, kern status, four corner pressures, and allowable-pressure utilization.

8 min

Elastic Foundation Settlement Example

Worked SI-unit example estimating immediate elastic settlement and evaluating the assumptions that control the result.

7 min

Percent Compaction Formula: Worked Field Density Example

Calculate percent compaction from wet density, moisture content, and Proctor MDD with a complete field dry-density and acceptance example.

8 min

Spread Footing Sizing Example

Worked service-load example for sizing and rounding a rectangular spread footing using allowable soil pressure.

11 min

Soil Compaction Testing: Field Density, Moisture, and Acceptance

A practical guide to field compaction testing, dry-density calculations, nuclear gauge and sand-cone methods, moisture control, test frequency, and acceptance decisions.

7 min

Field Density Testing Methods for Soil Compaction

Compare nuclear gauge, sand-cone, drive-cylinder, and replacement methods for field density testing, including limitations and selection factors.

11 min

Proctor Test Explained: OMC, MDD, Procedure, and Interpretation

A practical engineering guide to Standard and Modified Proctor testing, moisture-density curves, optimum moisture content, maximum dry density, and field compaction control.

7 min

Why Soil Fails Compaction and What to Check

Diagnose failed soil compaction tests by checking moisture, lift thickness, material variability, equipment, unstable support, and test validity.

11 min

Common Soil Mechanics Equations

Common soil mechanics equations with variables, assumptions, unit checks, and practical interpretation for stress, seepage, compaction, consolidation, strength, and earth pressure.

10 min

FE Civil Geotechnical Formulas

FE Civil geotechnical formulas organized by soil phase relationships, effective stress, compaction, seepage, consolidation, strength, earth pressure, and foundations.

10 min

How to Study Retaining Wall Problems

A repeatable PE Civil and FE Civil method for retaining-wall pressure diagrams, groundwater, surcharge, resultants, and stability checks.

11 min

PE Civil Geotechnical Study Guide

A specification-led PE Civil Geotechnical study plan covering topic weights, reference navigation, practice strategy, and the April 2027 exam change.

10 min

Slope Stability Concepts for PE Civil

PE Civil slope-stability concepts covering failure mechanisms, strength selection, pore pressure, infinite slopes, limit equilibrium, sensitivity, and result interpretation.

5 min

CBR Test Explained

CBR test explained for pavement subgrade and base support evaluation.

5 min

Concrete Volume Calculation

Concrete volume calculation explained for slabs, footings, and rectangular placements.

5 min

Culvert Sizing Basics

Culvert sizing basics, including inlet control, outlet control, slope, tailwater, and debris.

5 min

How to Estimate Concrete for a Slab

How to estimate concrete for a slab with thickness, waste factor, and field tolerance checks.

5 min

Manning's Equation Explained

Manning's equation explained for open channel flow, velocity, discharge, roughness, and slope.

5 min

Open Channel Flow Basics

Open channel flow basics for civil drainage design and field review.

5 min

Roadway Subgrade Explained

Roadway subgrade explained for pavement support, moisture sensitivity, compaction, and stabilization.

5 min

Stormwater Drainage Basics

Stormwater drainage basics for site grading, runoff, conveyance, and erosion control.

5 min

Active, Passive, and At-Rest Earth Pressure

Active, passive, and at-rest earth pressure explained for retaining walls and braced excavations.

5 min

Cohesion and Friction Angle Explained

Cohesion and friction angle explained as soil strength parameters for geotechnical calculations.

5 min

Expansive Clay Soil Explained

Expansive clay soil explained, including shrink-swell behavior, moisture changes, and foundation implications.

5 min

Factor of Safety in Slope Stability

Factor of safety in slope stability explained with interpretation, uncertainty, and practical use.

5 min

How Drainage Affects Retaining Walls

How drainage affects retaining walls and why water pressure often controls wall distress.

5 min

How to Read a Geotechnical Report

How to read a geotechnical report, including borings, lab data, groundwater, recommendations, and limitations.

5 min

Soil Unit Weight Explained

Soil unit weight explained for geotechnical calculations, including total, dry, saturated, and effective unit weight.

5 min

Terzaghi Bearing Capacity Explained

Terzaghi bearing capacity equation explained with terms, assumptions, and practical limitations.

5 min

USCS Soil Classification Explained

USCS soil classification explained with coarse/fine fractions, plasticity, and engineering interpretation.

5 min

What Is an Infinite Slope Model?

Infinite slope model explained for shallow planar slope stability screening.

5 min

What Is Bearing Capacity?

Bearing capacity explained for shallow foundations, including ultimate capacity, allowable pressure, settlement, and field checks.

5 min

What Is Plasticity Index?

Plasticity index explained for soil classification, clay behavior, and geotechnical interpretation.

5 min

Why Retaining Walls Fail

Why retaining walls fail, including drainage, surcharge, sliding, overturning, bearing, and construction issues.

5 min

Do You Need a Soil Report Before Building?

When a soil report is needed before building and what information it provides.

5 min

How Poor Drainage Damages Foundations

How poor drainage damages foundations through soil softening, erosion, expansive clay movement, and wall pressure.

5 min

How to Tell If a Slope Is Moving

How to recognize possible slope movement using cracks, scarps, bulging, seepage, and tilted features.

5 min

Should You Buy a House With Foundation Repairs?

How to think about buying a house with foundation repairs, including documentation, cause, and performance.

5 min

Signs of Expansive Clay Around Your Home

Signs of expansive clay around a home, including seasonal movement, cracks, and drainage clues.

5 min

What Causes Basement Wall Bowing?

Basement wall bowing explained, including lateral earth pressure, water pressure, expansive soil, and surcharge.

5 min

What Does a Geotechnical Engineer Do?

What a geotechnical engineer does for foundations, slopes, retaining walls, pavements, and site development.

5 min

When Should You Worry About Retaining Wall Cracks?

Retaining wall crack warning signs explained for homeowners and contractors.

5 min

Why Is My Foundation Cracking?

Foundation cracks explained for homeowners, including soil movement, drainage, settlement, and when to seek evaluation.

5 min

Why Soil Erosion Happens in Backyards

Backyard soil erosion explained with runoff, slope, vegetation, concentration of flow, and soil type.

5 min

Bearing Capacity Calculation Example

Worked bearing capacity example showing terms, units, allowable pressure, and interpretation.

5 min

Concrete Slab Volume Example

Worked concrete slab volume example with thickness conversion and waste factor.

5 min

Factor of Safety Example

Worked factor of safety example showing resistance-demand interpretation.

5 min

Infinite Slope Stability Example

Worked infinite slope stability example with slope angle, soil thickness, cohesion, friction, and pore pressure.

5 min

Manning's Equation Example

Worked Manning equation example calculating channel velocity and discharge.

5 min

Retaining Wall Active Pressure Example

Worked active earth pressure example using Rankine Ka, triangular soil pressure, and surcharge pressure.

5 min

Settlement Calculation Example

Worked settlement calculation example explaining stress increase, compressible layer thickness, and serviceability.

5 min

Soil Classification Example

Worked USCS soil classification example using gradation and Atterberg limits.

5 min

Surcharge Load on Retaining Wall Example

Worked surcharge load example for retaining wall lateral pressure.

5 min

Unit Weight Conversion Example

Worked unit weight conversion example between pcf and kN/m3.