Soil and Earth Works

Faculty of Applied Engineering and Urban Planning

Civil Engineering Department

Lecture 2 - Week 1

2nd Semester 2008/2009

UP Copyrights 2008

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Content

Objectives, components, applications of Soil

Index Properties of soil.

Types of Soil

Soil Characteristics

Subsurface Investigation

Soil Report

Excavation

Objectives, components, applications of Soil

The objectives of Soil mechanics science:

To determine physical properties of soil.

to use the physical information properties for design works of

foundations.

To improve soil science by researches…

Soil mechanics components:

Theoretical studying of physical properties.

Practical studying of physical properties.

Engineering applications related to soil mechanics:

1. Foundations:

Every foundations of structures, bridges, dams, tunnels,…etc

must be established on or under soil.

2. Soil as a structure material:

Soil can be used as a filling material and as a construction

material in damps, roads, bridges…etc.

3. Excavations and slopes:

4. Under ground structures & brace structure:

Such as basements, military structures,…etc

Objectives, components, applications of Soil

Problems related to soil works:

1. Soil Stability Problems. التربة ثبات مشاكل

2. Soil Settlement Problems التربة هبوط مشاكل

3. Environmental Related Problems. البيئة عن ناجمة مشاكل

4. Seepage Problems. المياه تسرب عن ناجمة مشاكل

5. Excavation Related Problems. الحفر عن ناجمة مشاكل

Objectives, components, applications of Soil

Problems related to soil works:

حدوث في تسبب التربة انجراف

(A .فجوة

A)B)

C)حي اضرار في تسبب أرضي انزالق

(B.سكنيجسر انهيار الي ادي التربة (C.هبوط

Soil of Mechanics Definition:

It is the science which investigate the properties, behavior of

soil as a construction and foundation material.

Soil Formation

Residual Soil. (granite, basalt, limestone,…etc)

Transported Soil.

Soil Structure:

Coarse grained soil (cohesive less soil) diameter > 0.002 mm

(Gravel زلط , sand رمل ….etc)

Fine grained soil (cohesive soil)- diameter < 0.002 mm

(Clay طين , silt طمي , …etc )

Objectives, components, applications of Soil

Index Properties of soil

Soil Volumes and Weights Relationship:

Index Properties of soil

Index Properties of soil:

1. Water content. المائي المحتوي

2. Specific Gravity. النوعي الوزن

3. In-site density. الموقعية الكثافة

4. Relative density. النسبية الكثافة

5. Consistency (Atterberg) limits. ) أتربرج ) حدود القوام حدود

6. Particle size distribution للحبيبات الحبي التوزيع

Soil Consistency (Atterberg) limits: ) حدود القوام حدود

أتربرج)

Definition of Consistency of soil: is the ability to formation based on the

fineness of grain,

water content.

Consistency of soil cases:1. Liquid State السائلة الحالة

2. Plastic State اللدنة الحالة

3. Semi-solid state الصلبة شبه الحالة

4. Solid State الصلبة الحالة

According to consistency limits soil can be classified

Soil Classification:

1. Soil Classification according to (USA Standard ASTM-ASCE)

ClaySilt Sand Gravel

Cobb

les

Boul

ders

Fine Med. Coarse Fine Med. Coarse Fine Med. Coarse

0.002

0.006 0.02

0.06

0.2 0.6

2

6 20

60 200

(mm)

طميرمل

طين

زلط

صغير حجر كبير حجر

2. Soil Classification according to (Particles Size)

Soil Classification according to (Unified Soil Classification System)

التربة لتصنيف القياسي التوحيد نظام

Organics: very weak soils and retain water; usually removed.

- Peat نباتات .etc ,وحل muck ,بقايا

Types of Soil

Soil Properties

Physical Properties Mechanical Properties

Gradation and Structure

Soil-Water Relationships

Atterberg’s Limits

Soil Compaction

Permeability

Compressibility

Shear Strength

Bearing Capacity

Soil Characteristics

Who needs to know soil characteristics?

1. the structural engineer, to determine how to support the building;

2. the architect, to site the building;

3. the contractor, to estimate the time and cost of the building;

4. the owner, because all the above affect the final price of the land.

Soil Characteristics

When do they need to know them?• the engineer needs this information prior to the

design;• the contractor, prior to pricing and planning;• the owner, prior to deciding if the project is

feasible.

Soil Characteristics

How is that knowledge obtained?• A visual exploration of the site and adjacent

buildings;

• test pits are dug to visually see the soils below;

• deeper studies require borings and dynamic penetrometers, samples, laboratory tests and a final report.

Field (site) tests of Soil

•Static punching test.

•Shear test.

•bearing test.

•Pressure test.

•Permeability test.

•Bonding test.

Site report

In the following a sample for geotechnical report content from Arab center for engineering studies.

Boring:

A boring is defined as a cylindrical hole drilled into the ground for the purposes of investigating subsurface conditions, performing field tests, and obtaining soil, rock, or groundwater specimens for testing.

Site Instigation Report

Common Excavation and Backfill Problems.

1.Unforeseen and differing conditions, such as a higher water table than predicted; unexpected large rock masses, or large boulders; unsuitable materials )undetected garbage pits, old foundations, abandoned utilities, etc.(.

2.Weather. The site must have access at all times. Therefore, the contractor may have to maintain all-weather roads. Borrow pits must also be used in all weather conditions.

3.Variable excavation volumes. Every site has some amount excavation.

Excavation

In good soil conditions and with shallow foundations, the excavation consists of scraping and stockpiling the organic topsoil.

This topsoil will be valuable for all the landscaping needs of the finished project.

The good sub-grade material is also scraped and stockpiled to create a compacted mat, or leveling pad, upon which is built the structure’s foundations.

Excavation must provide a natural slope so that rain or seepage will drain the water to a corner of the site, where it can be disposed of through pumps.

In poor surface soils, deeper excavations may be required to reach a stratum which has adequate bearing capacity. Otherwise, deep foundations (more expensive) may be required.

Excavation

Units of Measure:for excavation and backfill: cubic meterfor grading: square meter

Major Productivity Issues:Type of operation

(large sites versus confined spaces)Type of soil conditions

(from the best – rock to the worst - clays)Transportation of fill

(large distance to borrow pit, or moving within the site)

Expected Environmental Conditions (cold winters, hot summers, labor problems)

Excavation

Methods of field compaction:

1. Sand Cone Method الرمل مخروط طريقة

2. Rubber Balloon Method المطاطي البالون طريقة

3. Nuclear Method النووية الطريقة

Field Compaction

Equipments of Compaction in the Field:

1. Smooth-wheel rollers ملساء اسطوانية مداحل

2. Pneumatic or rubber-tired rollers مطاطية بعجالت مداحل

3. Sheep foot rollers الغنم أرجل مداحل

4. Vibratory rollers اهتزازية مداحل

Smooth-wheel rollers مداحلملساء اسطوانية

Pneumatic or rubber-tired rollers بعجالت مداحلمطاطية

Sheep foot rollers الغنم أرجل مداحل Vibratory rollers اهتزازية مداحل

Questions?!