Assessment of the Engineering Properties and Suitability of Some Tropical Soils as Backfill Materials

Little to none has been known about some soils excavated for backfilling purposes in Anambra State, Southeastern Nigeria. Thus, this study, which involved literature reviews, field sampling, and integrated geotechnical analyses, presents an assessment of their engineering properties and suitability as backfill (foundation, embankment, subgrade, and base) materials. Eight soil samples (ABG, NIM, OZB, NKA, OKJ, ORK, ULI, and NBI) from eight borrow pits were studied. Grain-size analysis revealed that the eight soils are dominantly composed of medium-coarse grains. Laboratory USCS identified and grouped the soils into five '“ GP, SW, SP, SC and CL. Their permeability coefficients ranged from 4.22x10-6 to 4.34x10-4m/sec, hence they are permeable. Compaction test revealed MDD range of 1.76'“1.94g/cm3, OMC range of 13.29'“17.10%, and bulk density range of 1.68'“1.90g/cm3. Their specific gravity ranged from 2.55-2.69. The soils have low natural moisture content, ranging from 1.61-8.00%. Atterberg limits of the fines showed that they are nonplastic to low plastic materials, with the highest PI as 12% (for the CL soil). The soils have low cohesion (0.66'“6.72kPa) but high frictional angle (32.54'“36.47o), except for the CL soil which has 27.31kPa cohesion and 19.34o friction angle. From the findings, it was deduced that, generally, these soils are good backfilling materials, though to varying degrees (SW?GP?SP?SC?CL), because of differences in their engineering properties. However, factors that could alter their good characteristics and suitability were discussed and recommendations given. Johnbosco C. Egbueri | Ogbonnaya Igwe | Chidiebere H. Nnamani"Assessment of the Engineering Properties and Suitability of Some Tropical Soils as Backfill Materials" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-1 , December 2017, URL: http://www.ijtsrd.com/papers/ijtsrd7041.pdf http://www.ijtsrd.com/other-scientific-research-area/geology/7041/assessment-of-the-engineering-properties-and-suitability-of-some-tropical-soils-as-backfill-materials/johnbosco-c-egbueri