Sedimentary and Residual SoilsResidual soils mostly in warm and humidregions where conditionsfor chemicalweathering are favorableandvegetationdoesn't allow easy transportation.Sedimentary soils mostly in areas which havebeenaffected bythe ice-times(northernhemisphere).26August31,2025?TUDelft
August 31, 2025 26 Sedimentary and Residual Soils • Residual soils mostly in warm and humid regions where conditions for chemical weathering are favorable and vegetation doesn’t allow easy transportation. • Sedimentary soils mostly in areas which have been affected by the ice-times (northern hemisphere)
Residual soilsDevelopwhenproductsofweatheringarenottransported butaccumulateinplace.Influencefactors-parentmaterial-climate (temperatureand rainfall)- drainage- time-vegetation- topography-bacterial activity27August31,2025TUDelft
August 31, 2025 27 Residual soils • Develop when products of weathering are not transported but accumulate in place. • Influence factors - parent material - climate (temperature and rainfall) - drainage - time - vegetation - topography - bacterial activity
Exampleof finegrained soilBlackcottonclayfrom Ethiopia,notoriousforitsswell and shrinkage characteristics28August31,2025?TUDelft
August 31, 2025 28 Example of fine grained soil • Black cotton clay from Ethiopia, notorious for its swell and shrinkage characteristics
Gradationblack cotton clay100806040200100,00010,0010,010,11sieve diameter [mm]29August31,2025TUDelft
August 31, 2025 29 Gradation black cotton clay 0 20 40 60 80 100 0,0001 0,001 0,01 0,1 1 10 sieve diameter [mm] percentage passing
SoilcharacteristicsPercentagepassingno.40sieve(0.425mm)=93%Clayfraction42%LL=99%,PL=45%,PI=54%ClassificationA-7Swellpotential24.6%30August31,2025TUDelft
August 31, 2025 30 Soil characteristics • Percentage passing no. 40 sieve (0.425 mm) = 93% • Clay fraction 42% • LL = 99%, PL = 45%, PI = 54% • Classification A-7 • Swell potential 24.6%