SHALLOW SURFACE COMPACTION DONE BY : Abdulmajeed alsultan

Outline Soil Improvement Compaction Field Compaction Equipment Field Compaction Testing

Soil Improvement

Methods for Soil Improvement Ground Reinforcement Ground Improvement Ground Treatment Stone Columns Soil Nails Deep Soil Nailing Micropiles (Mini-piles) Jet Grouting Ground Anchors Geosynthetics Fiber Reinforcement Lime Columns Vibro-Concrete Column Mechanically Stabilized Earth Biotechnical Drainage/Surcharge Electro-osmosis Compaction grouting Blasting Surface Compaction Deep Dynamic Compaction Soil Cement Lime Admixtures Flyash Dewatering Heating/Freezing Vitrification

Compaction

Objectives of compaction Decrease future settlements Increase shear strength Decrease permeability Control swelling and contraction Increases slope stability of embankments

Compaction Compaction Consolidation What is different between compaction and Consolidation ? Compaction Densification of soil by removing air from the voids. Consolidation Densification of soil by removing water from the voids.

Types of Compaction Types of Compaction : There are four types of compaction effort on soil :  Vibration Impact Kneading Pressure SATURATED SOIL NOT COMPACTABLE

Field Compaction Equipment

Equipment Smooth-wheel roller (drum) 100% coverage under the wheel Contact pressure up to 400 kPa Can be used on all soil types except for rocky soils Compactive effort : static weight

Equipment Pneumatic (or rubber-tired) roller 80% coverage under the wheel Contact pressure up to 700 kPa 7 to 13 wheels are arranged in two rows. Can be used for both granular and fine-grained soils. Compactive effort : static weight and kneading.

Equipment Sheepsfoot rollers 8% ~ 12 % coverage Contact pressure is from 1400 to 7000 kPa. Compactive effort: static weight and kneading.

Equipment Sheepsfoot rollers Suitable for : – fine grained soils – sands and gravels (with >20% fines) Unsuitable for: – very coarse soils – uniform gravels

Equipment Mesh (or grid pattern) roller 50% coverage Masses range from 5-12 Tones Contact pressure is from 1400 to 6200 kPa Compactive effort: static weight and vibration.

Equipment Mesh (or grid pattern) roller Suitable for: – well-graded sands – soft rocks – stony soils with fine fractions Unsuitable for: – uniform sands – Silty sands – Very soft clays

Equipment Vibrating drum on smooth-wheel roller Compactive effort: static weight and vibration. Suitable for granular soils

Equipment Vibrating Plate : Suitable for : – most soils with low to moderate fines content Unsuitable for: – large volume work – wet clayey soils

Equipment Power Rammer : Also called a trench tamper Suitable for : – trench back-fill – work in confined areas Unsuitable for: – large volume work

Variables-Vibratory Compaction There are many variables which control the vibratory compaction or densification of soils. Characteristics of the compactor: (1) Mass, size (2) Operating frequency and frequency range Characteristics of the soil: (1) Initial density (2) Grain size and shape (3) Water content Construction procedures: (1) Number of passes of the roller (2) Lift thickness (3) Frequency of operation vibrator (4) Towing speed

Field Compaction Testing

Field Density Testing Method   Sand Cone Balloon Dens meter Shelby Tube Nuclear Gauge Advantages Large sample Accurate Direct reading   obtained   Open graded    material Fast Deep sample Under pipe haunches Easy to redo More tests (statistical reliability) Disadvantages  Many steps Large area required Slow Halt Equipment Tempting to accept flukes Balloon breakage Awkward Small Sample No gravel Sample not always retained No sample Radiation Moisture suspect Encourages amateurs Errors Void under plate Sand bulking Sand compacted Soil pumping Surface not level Overdrive Rocks in path Plastic soil Miscalibrated Surface prep required Backscatter Cost Low Moderate High