Studies on chemical and geotechnical properties of marine sand

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Studies on chemical and geotechnical properties of marine sand

  1. 1. INTERNATIONAL JOURNALEngineering and TechnologyRESEARCH IN International Journal of Advanced Research in OF ADVANCED (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 2, March – April (2013), © IAEME ENGINEERING AND TECHNOLOGY (IJARET)ISSN 0976 - 6480 (Print)ISSN 0976 - 6499 (Online) IJARETVolume 4, Issue 2 March – April 2013, pp. 75-80© IAEME: www.iaeme.com/ijaret.asp ©IAEMEJournal Impact Factor (2013): 5.8376 (Calculated by GISI)www.jifactor.com STUDIES ON CHEMICAL AND GEOTECHNICAL PROPERTIES OF MARINE SAND Sivaramulu Naidu .D1 *, Madan Mohan Reddy .K2 and Vijaya Sekhar Reddy .M2 1 Senior Research Scholar, Department of Civil Engineering, SVUCE, Tirupati, AP, India. 2 Assistant Professor, Department of Civil Engineering, SKIT, Srikalahasti, AP, India. ABSTRACT Present study deals with the Chemical and Geotechnical properties of Marine Sand collected from Mypadu Beach, Nellore District, AP, India. Samples selected from two trial- pits one at a depth of 0.5-1.0 m (Pit-1) and second at a depth of 1.2-2.0 m (Pit-2) and conducted laboratory tests on Chemical and Geotechnical Properties. Samples are said to be Alkaline soils and Non-Cohesive because it’s having greater than 8.5 pH and grain sizes more than 98% range in 0.075- 1.18 mm respectively. The detailed test results and observations are discussed sequentially in the paper. Key words: Marine Sand, Chemical Properties, Geotechnical Properties, Maximum, Dry Density (MDD), Optimum Moisture Content (OMC), Safe Bearing Capacity (SBC). 1.0 INTRODUCTION A coastal plain corresponding to 0-150 meters covers almost entire coastal Andhra with some of the best agricultural land of the state. This area falls between two major river deltas, Krishna and Godavari and is largely composed of riverine and coastal alluvial soils and in some places red loams. Occupying 3% of the total area of the state the coastal soils are very deep (1.8-5mts) with coarse textured sandy subsoil. They are located all along the eastern coast, 3-12 km from the sea. Rapidly permeable soils due to very low day content and high amounts of sand. Neutral in reaction (pH 6.5- 7.5) with subsoil salinity due to high water table. Saline and alkaline soils belong to one group of problem, soil the extent of which is not precisely known as no systematic surveys were carried out to asses and map them. These soils are estimated to occupy about 1.0 per cent of the total area. The area under salt-affected soils in the coastal region is estimated to be 0.176 m ha [1]. 75
  2. 2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 2, March – April (2013), © IAEME The marine sediments present in the Kerala coast between 20 and 80m water depthcarry an appreciable amount of silica sand. Systematic mapping of the seabed andexploration in selected areas have indicated the presence of huge reserves of construction-grade sand in different sectors. Sandy sediments in the deeper, western part India arerelatively finer and fall in the fine to medium sand category. The carbonate content is 10-25% but in certain areas the sand bodies carry 10-15% clay and silt. In certain othersectors clay contents exceed 25%. The sand also carries economic heavy minerals likeilmenite, sillimanite, garnet, rutile, Zircon and monazite in small proportions [2]. The five sites chosen were submitted from moderate to high energy level ofdeposition and showed depositional clean graded bedding which is diagnosite of thepresence of storm surges, reflected through storm layers. Five areas and their sedimentaryfacies of the actual marine environment were chosen to apply the methodology used onthe transitional coastal sediments[3]. The pH varied from slightly acidic (5.83) to moderately alkaline (8.47) in the soilsof Sivagiri micro-watershed in Chittoor district of Andhra Pradesh. The variation in soilpH was related to parent material, rainfall and topography. Further, the KCl-pH valueswere lower than the water pH values, indicating the existence of net negative charge oncolloidal particles [4]. The electrical conductivity of the soils of Garakahalli watershed ranged from 0.02to 0.20 dSm-1 indicating non-saline nature of the soil. However, these soils did not showany relationship with depth. This may be due to the undulating nature of the terraincoupled with free drainage conditions, which favored the removal of releasing bases bythe percolating and drainage water [5]. The Inceptisols and Entisols of Shahibi basin inHaryana and Delhi were non-saline with electrolyte concentration ranging from 0.18 to0.95 dSm-1 [6].2.0 MATERIALS USED IN THE STUDY The soil samples were collected 2kms from the sea waterfront on the coast nearMypadu Beach, Nellore District, AP, India. Two trial-pits one at a depth of 0.5-1.0 m(Pit-1) and second at a depth of 1.2-2.0 m (Pit-2) and samples were collected in wetcondition from both trial pits (Pit-1 and Pit-2). Tests on soil samples were determined bystandard methods and conducted on Chemical Properties, Geotechnical Properties andSafe Bearing Capacity. It is mentioned here that three samples were taken at random andthe average values of various properties are taken as the test values.3.0 RESULTS AND DISCUSSIONS3.1 Chemical Properties Chemical tests were determined by the methodologies [7] suggested by Jackson(1973) for both Pit-1 and Pit-2 samples and observed the results of Chemical Properties ofmarine soil samples are tabulated in Table 1. 76
  3. 3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 2, March – April (2013), © IAEME Table 1. Chemical Properties of Marine Soils Samples Electrical Total Conductivity Dissolved Alkalinity Hardness Chemical Chlorides (µs/cm) Solids (ppm) (mg/l as (mg/l as pH Properties (mg/l) CaCo3) CaCo3) Wet Dry Wet Dry Pit -1 670 1387 612 8.62 815 710 2405 2100 Pit -2 612 1220 574 8.58 702 650 1890 1760Soils with a pH greater than 8.5 are considered alkaline [1]. Samples collected from thesource were having pH > 8.5 and these soils considered as alkaline soils.3.2 Geotechnical Properties Tests on soil samples were determined by standard methods and observed results aretabulated in Table 2. It is observed that the liquid limit, Plastic Limit, Plasticity Index and Free Swell Indexwere zero because of both Pit-1 and Pit-2 samples were cohesion less sand particles. Table 2. Geotechnical Properties of Marine Soil Samples Natural Angle of In-Situ Moistur Internal Bulking Silt + Geotechnical Specific Sand Density e Friction of Sand Clay Properties Gravity (%) (kN/m3) Content (φ in (%) (%) (%) degrees) Pit-1 10.867 25.99 29`29” 2.38 12 98.13 1.86 Pit-2 12.72 27.14 31`9” 2.35 6 99.97 0.23 77
  4. 4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 2, March – April (2013), © IAEMEGrain size distribution For determination of grain size distribution of marine samples, sieve analysis test wasperformed. From the test data, the particle size distribution curve was plotted from which itwas found that the soil consists of more than 98% of particles range in 0.075mm-1.18mm forboth Pit-1 and Pit-2 samples. Therefore the soil samples said to be sand particles. The grainsize distribution curve is depicted in Figure 1.Compaction test The standard proctor compaction test was carried out with remoulded soil sample withvarying moisture content. In each test, the standard Proctor mould (size: 100 mm diameter x127 mm height) was filled with soil-water water mixture in three equal layers, each layerbeing compacted by 25 blows of a 25 N rammer with a height free fall of 300 mm. From thetest results observed Maximum Dry Density (MDD) versus Optimum Moisture Content(OMC) is depicted in Figure 2. The value of MDD and OMC (depicted in Figure 2) for Pit-1and Pit-2 was observed 16.68 kN/m3, 16.29 kN/m3 and 15.48%, 15.62 % respectively.Safe Bearing Capacity It is observed from the results Ultimate Bearing Capacity (UBC) and Safe AllowableBearing Capacity (SBC) for Pit-1 were found to be 190 kN/m2 and 63 kN/m2 respectivelyafter considering factor of safety 3.0 and the settlement of 3.80 cm. For Pit-2, UBC and SBC were found to be 200 kN/m2 and 67 kN/m2 respectively afterconsidering factor of safety 3.0 and the settlement of 3.865 cm. However the SBC ofcohesion less, loose, dry and fine sand may be limited to 100 kN/m2 and allowable settlementof 5.0 cm in accordance with the IS: 6403-1981 [8]. 78
  5. 5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 2, March – April (2013), © IAEME4.0 CONCLUSIONS1. The present studies explain the knowledge about the marine sand in connection with its Chemical Properties, Geotechnical Properties and soil Safe Bearing Capacity.2. The Soil samples are alkaline because of both Pit-1 and Pit-2 having greater pH, than the allowable value of 8.5.3. Grain size distribution of Marine Sand samples shows that the sediments consist of more than 98% of sand content when sieved through 0.075 - 4.75 mm size sieves.4. It is observed that the liquid limit, plastic limit, plasticity index and Free Swell Index were zero because of both Pit-1 and Pit-2 were fine sandy particles of the Marine soil.5. The value of Cohesion were found to be zero and hence only Direct Shear test was conducted for finding results of the MDD and OMC in present in soil samples. The test results of MDD and OMC for Pit-1 and Pit-2 is 16.68 kN/m3 and 16.29 kN/m3 and 15.48% and 15.62% respectively.6. From the results the UBC and SBC of Pit-1 and Pit-2 were found to be 190 kN/m2, 200 kN/m2 and 63 kN/m2, 67 kN/m2 respectively, after considering factor of safety 3.0.7. The settlement of foundation is observed for Pit-1 and Pit-2 were 3.80 cm and 3.865 respectively. These values are also well within the allowable settlement of 5.0 cm as per the code.REFERENCES[1] www.inseda.org/...Soil%20Science%20(SSS)/ Soils%20of%20Andhra%20Pradesh -369. doc, dated.19/03/2013.[2] Sukumaran .P.V., et. Al. (2010), “Marine sand resources in the south-west continental shelf of India”, Indian Journal of Geo-Marine Scinces, Vol.39, No.4, pp.572-578.[3] Martine .L.R and Barboza .E.G (2005), “Sand-gravel Marine Deposits and Grain-Size properties”, Gravel, Vol. N3, pp.59-70. 79
  6. 6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 2, March – April (2013), © IAEME[4] Thangasamy .A, Naidu .M.V.S, Ramavatharam .N and Raghava Reddy .C (2005), “Characterization, classification and evaluation of soil resources in Sivagiri micro- watershed of Chittoor district in Andhra Pradesh for sustainable land use planning”, journal of indian society of soil science, Vol.53, pp.11–21.[5] Pillai .M.Y and Natarajan .A (2004), “Characterization and classification of dominant soils of parts of Garakahalli watershed using remote sensing technique. Mysore”, Journal of Agricultural Science, Vol.38, pp.193-200.[6] Swarnam .T.P, Velmurugan .A and Rao .Y.S (2004), “Characterization and classification of some soils from Shahibi basin in parts of Haryana and Delhi”, Agropedology, Vol.14, pp. 114-122.[7] Jackson .M.L (1973), “Soil Chemical analysis”, Prentice Hall of India, Pvt. Ltd., New Delhi, India.[8] IS: 6403-1981, Code of Practice for Determination of Breaking Capacity of Shallow Foundations, Bureau of Indian Standards, New Delhi, India[9] M. Alhassan and I. L. Boiko, “Effect of Vertical Cross-Sectional Shape of Foundation and Soil Reinforcement on Settlement and Bearing Capacity of Soils”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 2, 2013, pp. 80 - 88, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.[10] K.V. Maheshwari, Dr. A.K. Desai and Dr. C.H. Solanki, “Bearing Capacity of Fiber Reinforced Soil”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 1, 2013, pp. 159 - 164, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.[11] Sitiradziah Abdullah, Ahmad Shayan and Riadh Al-Mahaidi, “Assessing the Mechanical Properties of Concrete Due to Alkali Silica Reaction”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 1, 2013, pp. 190 - 204, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. 80

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