Performance evaluation of weak subgrade soil under increased surcharge weight

Effect of illite on the mechanical properties of subgrade soil under varying surcharge loads

“…Fig. 12 shows the measured M R values of both soil types plotted against the equation developed by Abubakar [ 14 ], which shows that A-6 soil underestimates and A-2-6 soil overestimates the M R values of subgrade soil.

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“…However, in industry the use of surcharge weight in CBR testing is not well-defined. The overburden pressure resulting from the weight of the pavement on the soil is simulated using surcharge weight [ 14 ]. Razouki [ 15 ] suggested that a surcharge weight of 2.27 kg is suitable for pavement thicknesses of 63.5 mm, but the weight on CBR mould should not be less than 4.5 kg.…”

“…To calculate the surcharge weight for CBR testing in the design, contractors and construction companies take the thickness of pavement layers above the subgrade into consideration [ 14 ]. This approach often involves using higher surcharge weights compared to the standard weight used in a CBR test.…”

“…The presence of stabilizers and admixtures can have a combined effect on soil performance [ 14 ]. Some authors have investigated the effects of moisture content variation, compaction effort and soaking period on the resilient modulus and California Bearing Ratio (CBR) of sand rich with gypsum or other stabilized soils [ 19 ].…”

“…Powell [ 25 ] also used wave propagation technique for soil having CBR 1 to 12. Abubaker [ 14 ] gave the relationship for weak and stiff soil by apply different surcharge load on soil sample. types of soil.…”