Assessment of the influence of moisture content of soil on the DCPI.

Abstract

Soil investigation for any engineering structure is a critical aspect because the soils are burdened with the task of transferring all loading stress to underlying layers. To date, various methods have been employed in the process of soil exploration. The challenge however with most methods of soil exploration is the financial limitation of certain projects. Engineers and scientists therefore always purpose to find timely and cost-effective methods of soil exploration. In line with this development, one can’t fail to appreciate a dynamic cone penetrometer introduced by Scala in 1956. Over the past decades improvements on this equipment in terms of recommendations by various researchers have helped refine the usage of the DCP. Concerning the study of DCP as per its growing acceptability as a method of soil investigation, its functionality in attaining results may be deemed unreliable depending on apparent soil conditions. This research investigated the influence of the moisture content of soil on DCPI. It was carried out on a sample obtained from a burrow pit and the sample was tested for its relevant properties as per BS 1377:1990. The soil material was moulded into a model text box in layers of 150mm while varying the moisture contents of the soil. DCP test was carried out on the layers in accordance ASTM D6951-03. The number of blows per unit time was also varied for each test. The DCPI was calculated from the obtained results and the research shows that for the DCPI was lowest at the OMC of 15.8%. This was done for densities of 71%MDD as the loosest soil density at the equilibrium moisture content of the soil and 75% MDD. The relationship between moisture content and DCPI is defined by a reduction in DCPI as moisture content increases on the dry side of the OMC.