Natural satbilization of soils
Soil stabilization bytermites
Published on: Mar 3, 2016
Transcripts - Natural satbilization of soils
Natural Stabilization of Soils With Special Reference toEntomological Considerations by Dr.A.S.Nene and Y.D. Parihar
Insects or Soil EngineersTermites, Wasps and earthworms can be consideredas soil engineers because of their effects on soilproperties.
Introductionv In nature there are insects that stabilize and use soil for their dwellings. Such insects are Wasps, Earthworms and Termites etc.v The stabilization agents used by these insects are yet unknown.v Many ancient Indian Texts on Engineering mention the use of ant-hill soils for mud plaster, mud flooring, metallurgical crucibles and clay idols.
Fascinating Facts about Termites and Termitarium (Ant-hills)Ø Termites use adjacent soil grains for construction of ant-hill.Ø These particles are coated with sticky rapidly hardening material secretions from mouth or rectum.
Ø On drying the material becomes hard as rock.Ø Strength of the ant-hill increases with time.Ø Ant-Hills are very strong and need sharp tools, or even dynamites to destroy.Queen’sChamber
Ø Size and shapes of termitarium are indicative of the species of termites.Ø Shapes may like a mushroom, column, pyramid sheet piles etc.
Ø Size may be as large as 4 m. at base and height up to 9 m.Ø On a scale of relative size, a man made pyramid would be 4 km high !Ø In spite of the huge soil mass used for giant ant-hills, there is no cavity in the ground.
Research Objectives§ To study the engineering properties of ant-hill soil and compare with the properties of parent soil from which the ant-hill are constructed.§ To Conduct Chemical analysis of ant-hill soil for pH, phosphates and sulphate content.§ To Conduct X ray Diffraction tests.§ To Identify the secret of construction of ant-hills which will be very useful for low cost mud constructions.
The secret of construction of ant-hills Cellulose 54.6% Pentosans 6.5% Cellulose 18.0% Pentosans Lignin Lignin 18.0% 27.4% 75.5% FoodBefore Digestion After Digestion
1. Field visits and Samples collection• Samples were collected from seven sites of Vidarbha.• For each site two samples were collected.• The first sample was of parent soil and the second sample was from ant-hill.• About 10 kg soil samples were collected from each site for laboratory testing.
2. Laboratory Investigations Part 1Following laboratory tests were conducted on 14samples collected from seven sites. Ø Differential free swell test (DFS ) Ø Grain Size Analysis (GSA) Ø Consistency Limits (Liquid Limit -LL, Plastic Limit -PL and Shrinkage Limit -SL
35 65 Parent Anthill Parent Anthill 30 60 25 55 Liquid Limit %DFS Value % 20 50 15 45 10 40 5 35 0 30 S1 S2 S3 S4 S5 S6 S7 S1 S2 S3 S4 S5 S6 S7 Site No Site No Reduction in DFS Value and Nominal reduction in Liquid Limit
27.5 27.5 Parent Anthill Parent Anthill 25 25 22.5 20 22.5 Shrinkage Limit % 17.5Plastic Limit % 20 15 12.5 17.5 10 15 7.5 5 12.5 2.5 10 0 S1 S2 S3 S4 S5 S6 S7 S1 S2 S3 S4 S5 S6 S7 Site No Site No Increase in Plastic Limit and Shrinkage Limit
60 Parent Anthill 50Swelling Pressure kPa 40 30 20 10 0 S1 S2 S3 S4 S5 S6 S7 Site No Reduction in Swelling Pressure
Ø Swelling Pressure test (Constant volume method)Ø Chemical Test on soils for pHØ Sulphate and Phosphate content testØ X Ray Diffraction test.
Laboratory Investigations Part 2 Laboratory tests were conducted on parent soils from three sites to findØ The effect of lignin on Consistency Limits of soils.Ø The effect of lignin on dry density- Optimum moisture content of soils
60 26 0% 4 8 12 0% 4 8 12 50 22 40 Plastic Limit %Liquid Limit % 30 18 20 14 10 0 10 CHandur Rajura Nagzira CHandur Rajura Nagzira Effect of Lignin on Liquid Limit Effect of Lignin on Plastic Limit Decrease in Liquid Limit but increase in Plastic Limit
24 0% 4 8 12 20Shrinkage Limit % 16 12 CHandur Rajura Nagzira Effect of Lignin on Shrinkage LimitIncrease in Shrinkage Limit
ConclusionsBased on the review of literature and limited laboratoryinvestigations following conclusions were drawn.vThe swelling characteristics of parent soils aredrastically reduced in Natural stabilization by termites.vThere is negligible change in soil Constituents of soil.vLignin of the cementing material is the secret ofstrength of ant-hills.vMore research is necessary to create similarcementing agent on large scale.
References1. Eugene Marais (1973) “Sole of white ants”, Penguin Publications, London.2. Roonwal M.L. (1979) Termite Life and Termite control. Scientific Publishers Jodhpur.
PublicationsØ Nene, A.S. and Parihar, Y.D. (1992)"Natural Stabilization of Expansive Soil" Proceeding of Indian Geotechnical Conference 1992, Calcutta, 18-20 December 1992, Vol.1 .pp 207-209.Ø Nene, A.S. and Parihar, Y.D. (1996) “Natural Stabilization of soils with special reference to Entomological considerations" Second International Conf. On Soft soil Engineering, Nanjing (China) May 17-20.