Soil Mechanics Questions and Answers Fully Solved 100%

accuracy of k determined in lab depends on 6 variables - ️️temperature of fluid, viscosity of fluid, trapped air bubbles present in soil specimen, degree of saturation of the soil specimen, migration of fines during testing, and duplication of field conditions in the lab boutwell permeameter - ️️hole is drilled and casing placed in it. casing filled with water and falling-head permeability test is conducted, hole is deepened, repeat hydraulic gradient - ️️i = ∆h/L Darcy's Law - ️️discharge velocity of water through saturated soils v = ki k is hydraulic conductivity (coefficient of permeability) seepage velocity - ️️velocity of water through void space constant-head test - ️️laboratory determination of hydraulic conductivity where the difference of head between inlet and outlet remains constant falling-head test - ️️laboratory determination of hydraulic conductivity where water from a standpipe flows through a soil. head difference and time are recorded at t1 and t2 hydraulic conductivity and void ratio for granular soils - ️️increases linearly 3 methods to estimate in situ hydraulic conductivity of compacted clay soils - ️️boutwell permeameter, constant-head borehole permeameter, porous probes Permeability - ️️soils permeable due to existence of interconnected voids through which water can flow from high energy points to low energy points constant-head borehole permeameter - ️️constant head is maintained by supplying water, rate of flow q is measured porous probes - ️️driven into soil, constant or falling-head permeability test is performed laboratory consolidation tests - ️️hydraulic conductivity of saturated cohesive soils can be determinedflow line - ️️line along which a water particle will travel from upstream to downstream side in the permeable soil medium equipotential line - ️️line along which the potential head at all points is equal flow nets - ️️can be used to determine the uplift pressure at the base of a hydraulic structure stress in saturated soil without seepage - ️️stress = H*gamma w + (HA - H)*gamma sat sigma - ️️stress = effective stress + pore pressure sigma prime - ️️effective stress (intergranular stress) sum of vertical components of all intergranular contact forces over a unit gross cross-sectional area