Determination of In Situ Soil Density by Sand Cone Method Using Locally Available Sands

Abstract

In Bangladesh Ottawa sand is used to find out in situ soil density using Sand Cone Method. Ottawa sand is very expensive and it is always imported from abroad. Usually it requires much time to import this item. Instead of Ottawa sand, Sand Cone Method might use locally available sand as an alternative material for determining in situ soil density. In Bangladesh, local sand is available in abundance and compared with Ottawa sand it is also much cheaper in price. In this research the quality and suitability of locally available sand in and around Khulna district are assessed for determining in situ density using Sand Cone Method. Five samples of sand named by Sylhet sand, Kushtia sand, Fultala sand, Bogjhuri sand and Mongla sand were collected from nearby business centers. Original sand and some graded sands of each sample were under investigation to ascertain their suitability of use in lieu of Ottawa sand in determining in situ soil density. Four gradations were considered and those were (i) passing # 16 and retained in # 30, (ii) passing # 30 and retained in # 40, (iii) passing # 40 and retained in # 50 (iv) passing #30 and retained in # 50 sieve. Each of the original samples has been characterized by determining its index properties, Grain size distribution. Specific gravity and density are determined for each sample of original and graded sands. These properties are compared with those recommended by ASTM (1989) for selecting suitable sand in Sand Cone Method. From this study it was found that original sands of all selected places in Bangladesh did not satisfy the ASTM (1989) criteria for Ottawa sand. In case of graded sands, Sylhet sand satisfied all the required ASTM criteria for four gradations, while Kushtia and Fultala sands satisfied fully for three gradations except the gradation passing # 16 and retained in # 30 sieve. Bogjhuri and Mongla sands did not satisfy all the required criteria. So, the above graded sands that satisfy the criteria of Ottawa sand as mentioned in investigation can be used in sand cone method in lieu of costly Ottawa sand.