# Head Permeability Test Lab Report

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6.4.2 DISTURBED SOIL SAMPLE Allow the soil sample to dry in the air for some hours and mix it thoroughly Take a representative sample of about 2.5 kg from the thoroughly mixed air dried (or oven dried) soil Determine the moisture content of the sample, w (Experiment 1) Add required quantity of water to get the desired moisture content and Mix the soil thoroughly Weigh the empty compaction permeameter mold. Grease the inside slightly, then clamp it between the compaction base plate and extension collar. Place the assembly on a solid base and fill it with soil sample to middle of extension collar and compact it with the compacting equipment On completion of compaction, remove the collar and excess soil. Weigh the mold with compacted…show more content…
6.5 OBSERVATIONS AND RECORDING The flow is very low at the beginning, gradually increases and then becomes constant. Constant head permeability test is suitable for cohesionless soils. For cohesive soils falling head method is suitable. 6.6 Presentation of data and Calculations We need to determine the coefficient of permeability which is reported in cm/sec at 27o C, the dry density, the void ratio and the degree of saturation 6.6.1 COMPUTATIONS Coefficient of permeability for a constant head test is given by = 6.4 where k = coefficient of permeability in cm/sec Q = quantity of water passing through the sample in a time t q = Discharge cm3/sec = Q/t L = Length of specimen in cm A = Cross-sectional area of specimen in cm2 h = Constant head causing flow in cm ∆h = h = h1 – h2 The variables can be calculated as follows: Quantity of flow, Q Q = Wbw – Wb 6.5 The Head, h h = h1 – h2 6.6 Cross-sectional area of sample,