Subsurface Investigation Building structure system

FIELD TESTING

Soil Boring Machine Flight Auger system Wash Boring

Rotary Drilling Undisturbed Machine Require

Wash Boring Rotary Drilling Percussion Drilling

Sampling Thin wall (Shelby tube) Split Sampler

Standard Penetration test

Field Testing Standard Penetration Test (SPT) ASTM D1586 – 140 lb (63.5 kg)- Falling 30 inches (0.76 cm) Test in mm Use only the 2 last 2 interval =150x2 =300 mm = 1 ft The unit is Blow per foot

Interpretation Classify soil to be clay or sand C for clay  for sand Calcuate the strength parameter -Correction for SPT -Calculate the strength parameter

Strength parameter for sand (Peck’s Approach) No effective stress calculation Empirically correlation

Parry (1977) Adjustment with overburden pressure

Correction for N-value according overburden pressure

Correlation q u vs N (Sambhandharaksa, 1985)

Strength parameter for clay Procedure for classify soil Start with water content and unit weight Check strength parameter with index properties Divide soil layer

Soil Boring Number of Boring Depth of boring Thailand Depth of Boring is 30 or 60 m.