Soil Mechanics Handwritten Notes PDF

Key takeaways

• Eight sections covering the full Soil Mechanics (Geotechnical Engineering I) syllabus.
• A table of phase relation terms with all the key unit weight formulas.
• Worked examples for phase relations, consolidation settlement and active thrust.
• Tables for Proctor tests, consolidation parameters, shear tests and earth pressure coefficients.
• Original Uncodemy notes based on the common syllabus and IS 1498 classification.

About these Soil Mechanics notes

Soil Mechanics is the base of all geotechnical work, and almost every topic has a formula you must derive or use. These notes keep the derivations short and put the commonly confused formulas, such as the unit weights and the consistency indices, side by side.

These are original Uncodemy revision notes. They follow the topics common to most Indian B.Tech Civil syllabi for Soil Mechanics, written in a neat handwritten style with formulas boxed and key numbers highlighted. They are short notes for revision, not a replacement for your textbook or class notes.

What's inside the notes: unit by unit

The PDF moves from what soil is made of to how it carries water, load and pressure.

Unit 1: Phase relations

• Three-phase diagram: void ratio, porosity, degree of saturation, water content and air content.
• Unit weights: Se = wG and the bulk, dry, saturated and submerged unit weight formulas, with an example.
• Relative density: how it describes loose and dense sand.

Unit 2: Index properties and classification

• Particle size: sieve and hydrometer analysis, Cu, Cc and effective size.
• Atterberg limits: liquid, plastic and shrinkage limits, PI, LI, CI, activity, sensitivity and thixotropy.
• IS classification: coarse and fine soils and the plasticity chart A-line.

Unit 3: Permeability and seepage

• Darcy's law and tests: constant head and falling head permeability tests.
• Layered soils: equivalent horizontal and vertical permeability.
• Flow nets and quick sand: seepage quantity, critical hydraulic gradient and piping remedies.

Unit 4: Effective stress and compaction

• Effective stress: Terzaghi's principle, seepage effects and the capillary zone.
• Compaction: OMC and MDD, standard and modified Proctor tests, zero air voids line and field control.

Unit 5: Consolidation

• NC and OC clays: OCR and preconsolidation pressure.
• Parameters: av, mv, Cc and cv in one table.
• Settlement and time: settlement of NC clay, time factor and drainage path, with an example.

Unit 6: Shear strength

• Mohr-Coulomb: failure envelope, failure plane angle and the σ1-σ3 relation.
• Shear tests: UU, CU, CD, unconfined compression, vane shear and direct shear and where each is used.
• Pore pressure: Skempton's A and B parameters and the dilation of dense sand.

Unit 7: Stress distribution

• Boussinesq and Westergaard: stress below a point load and the difference between the two.
• Approximate methods: 2:1 method, pressure bulb and Newmark's chart.

Unit 8: Earth pressure and slopes

• Earth pressure: at-rest, active and passive coefficients, thrust, surcharge, water table and tension cracks, with an example.
• Slope stability: infinite slopes with and without seepage, slip circle, method of slices and Taylor's number.

How the PDF is laid out

Each section opens with short definitions in bullet form, followed by tables that compare types, tests or methods. Formulas are written in separate boxes so they stand out when you flip through the pages, and the values that examiners ask most often are highlighted. Short tip boxes point out exam favourites and common traps. Wherever a formula is used in exams, a short solved example shows the steps with real numbers. The last page lists 10 most asked practice questions so you can test yourself after revising.

How to revise Soil Mechanics

• Master the phase diagram. Draw it for every three-phase problem. Most unit weight formulas follow from it in a few lines.
• Write derivations once a week. Falling head formula, critical gradient and the consolidation settlement equation are favourites.
• Draw stress diagrams. Total stress, pore pressure and effective stress diagrams with depth make seepage questions easy.
• Learn the shear test table. Drainage condition and field use for UU, CU and CD answer many short questions.
• Practise earth pressure with layers. Add water table and surcharge one at a time until it feels routine.

Exam focus: high-weightage topics and numericals

Soil Mechanics papers have a numerical in almost every unit. Prepare these areas:

• Phase relations and their derivations.
• Atterberg limits and IS classification.
• Permeability tests, flow nets and quick sand.
• Terzaghi's consolidation theory.
• Shear strength tests and Rankine's earth pressure theory.

Typical numericals to practise

1. Find void ratio, degree of saturation and unit weights from given data.
2. Find equivalent permeability of layered soil in both directions.
3. Find seepage per metre width from a flow net.
4. Find consolidation settlement of an NC clay layer and the time for a given degree of consolidation.
5. Find active thrust on a retaining wall with water table and surcharge.

A one-week plan with these notes

If your Soil Mechanics exam is a week away, this plan covers the whole PDF once and leaves time for practice.

• Day 1: Phase relations and Index properties and classification. Read the section, then close the PDF and write the key formulas and tables from memory.
• Day 2: Permeability and seepage and Effective stress and compaction. Read the section, then close the PDF and write the key formulas and tables from memory.
• Day 3: Consolidation and Shear strength. Read the section, then close the PDF and write the key formulas and tables from memory.
• Day 4: Stress distribution and Earth pressure and slopes. Read the section, then close the PDF and write the key formulas and tables from memory.
• Day 5: redo every solved example in the notes without looking at the steps.
• Day 6: answer the 10 practice questions at the end of the PDF under a time limit.
• Day 7: solve one recent official paper from your university and revise the topics you got wrong.

Who these notes are for

• B.Tech semester exams: covers the Soil Mechanics or Geotechnical Engineering I paper with solved examples.
• GATE CE basics: phase relations, seepage, consolidation, effective stress and Rankine pressure are asked in GATE CE every year.
• Site work and interviews: site engineers and interview candidates get quick notes on compaction control, soil classification and shear tests.

Check your own syllabus and the current IS codes

Universities split and order these topics differently, and some leave out units or add extra ones. Match the notes against your own university syllabus and recent official question papers before you plan your revision. The notes use IS 1498 for soil classification and the IS particle size ranges. Laboratory tests are covered by the IS 2720 series. Codes are revised from time to time, so check the current edition and any amendments before you use a value in design work or quote it in an answer. Uncodemy keeps a list of previous year question paper sources if you want official papers to practise with.

Download Soil Mechanics Handwritten Notes PDF

Sources and further reading

• Bureau of Indian Standards (IS codes)
• NPTEL: Civil Engineering courses (IIT faculty)