Seminar on Site Investigation

8/4/2019 Seminar on Site Investigation

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Introduction

1- Geotechnical investigation2- Various field test


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GEOTECHNICAL INVESTIGATION

1-Site Exploration

2- Measurements of Soil Properties

3- Field Instrumentation4- Identifying Engineering Problems


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Site Exploration

1-Define the depth of the proposed foundation2- Evaluate the load-bearing capacity of the foundation3- Estimate the probable settlement4- Identify potential foundation problems5- Define ground water conditions


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The site exploration programshould include the following

1-Data Collection2- Terrain Analysis3-Site Reconnaissance4-Subsurface Sectioning5-Sample Recovery


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DATA COLLECTION

1- Type of structure

2- General use of the structure3- Column load4- Column spacing5- Building code


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TERRAIN ANALYSIS

1- Geomorphic characteristics of the site (Landform)2- Relief amplitudes3- Drainage basins4- Vegetation5- Climate conditions, weathering, frost action, erosion, and masswasting.


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SITE RECONNAISSANCE

1- General topography, existing of drainage, ditches, etc.2- General conditions of the soil

3- Type of vegetation4- Surface water condition5- Accessibility of the site


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SUBSURFACE SECTIONING

1-Seismic refraction (For large areas)2- Test pits (for shallow depths)3- Auger boring (Manual, Mechanical)4- Wash boring5- Core boring


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Test boring is the most usablemethod

1- Equipment Selection2- Boring Spacing3- Boring Depths


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Equipment Selection

This depends on:

1- Terrain features2- Accessibility

3- Geologic Conditions4- Boring depths5- Sample types6- Nature of the project


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Boring Spacing

The spacing usually range from 30 ft to 1600 ft.


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Depth of Boring

1- In general, boring should be extended to at least 1.5 to 2 timesthe minimum width of the loaded area.

2- In the case of very heavy structures (bridges), boring in most

cases are extended to bed rock, or at least one boring should be

extended to bedrock.


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SAMPLE RECOVERY

1-Disturbed2- Undisturbed


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Methods Of Sample Recovery

1- By hand2- Split spoon3- Scraper bucket4- Thin wall tube (Shelby tube)


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METHODS OF EXPLORATION

1-Direct and semi-direct methods

2-Indirect methods


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DIRECT AND SEMI DIRECT

METHODS

1-Test pits2-Auger boring3-Wash boring4-Percussion drilling5-Rotary drilling


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PLANNING AND EXPLORATION

PROGRAMME

1- Site plan of the area2- A layout plan of proposed structure3- Location of bore holes and field tests4- Planning of other field tests


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PLANNING AND EXPLORATIONPROGRAMME

1- Depth of boring

2-soil sampling


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FIELD TESTS

1-Standard Penetration Tests (SPT)2-Dynamic Cone penetration Tests (DCPT)3-Plate Load Tests


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STANDARD PENETRATION TEST

1- Determination of insitu parameters of soil2- Determination of bearing capacity


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DYNAMIC CONE PENETRATIONTEST

1-Investigation of compactness of sub-soil layer with out making aborehole

2-Penetration resistance of soils is used for estimation of bearingcapacity


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PLATE LOAD TEST

1- Determination of allowable bearing capacity of sub soil2- Suitable for gravel/boulder strata when SPT and DCPT does notgive dependable results3- Also used to determine the modules of subgrade reaction (K)useful for design of rigid pavements


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Conclusion

Steps mentioned above should be followed,in order to have proper foundation.


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Documents

Seminar on Site Investigation