If the thickness of the black cotton soil is only up to 120 cm it should be completely removed and foundation laid on the soil below. Chanuhan rajiv and et al 2009 has studies the strength improvement of soil treated with lime and flyash mix for durability criteria. Please note all black cotton soil is not expansive and all expansive soil is not black. In civil engineering aspects black cotton soil is giving hazardous problems to engineers. This video is about my residential site under reamed pile foundation process in black cotton soil. Which type of soil and foundation is recommended for protection of building in earth quake zones. This is the most abundant type of soil in india on the basis of percentage share of total area.
So that pressure on the soil does not exceed its allowable bearing capacity and restricts the settlement of the structure within the permissible limits. Pdf study of stabilization of black cotton soil using lime. Regur means cotton best soil for cotton cultivation. Figure 1 damages to various structures in expansive soil black cotton soil. In these type of foundation the structure is anchored to the ground at a depth where ground movement due to changes in moisture content negligible. Jan 23, 2016 soil types of india alluvial soils black soils characteristics, chemical properties, distribution, divisions. In black cotton soil, the minimum depth of foundation should be a 4 m below. It is the expansive nature of soil which is challenging and creates problems and not colour. Pdf search for solutions to problems black cotton soils.
Naturalpaves earthfriendly stabilization technology uses native soils rather than hauledin materials, eliminating the need to import costly base or aggregate materials to build a subbase for subsequent paving or chip sealing. The problem has assumed economic importance at the national plane, as approximately one third of the surfacial deposits of the country are of black cotton soil. The foundation in black cotton soilexpansive soil mystery revealed. The soils of peninsular india are formed by the decomposition of rocks in situ, i. The construction of foundation for structure on black cotton soils poses a. The main characteristics of this type of soil are that when it is wet, it swells and exerts pressure of about 16500kgm 2 and when dry, cracks are developed into the soil upto the depth of 2 to 2. Search for solutions to problems in black cotton soils. Foundations in black cotton soil civil engineering. If unavoidable the building shall rest either on a rigid raft foundation. Stabilisation of black cotton soil using admixtures pankaj r. Jun 12, 2018 soil or rock deeper within the earth in this lecture i mentioned the factors affect the choice of a foundation. How to make my home in black cotton soil plot quora. Jun 04, 2017 foundation is an important part of the structure which transfers the load of the structure to the foundation soil. The more natural alternative is also the most costeffective.
Nov 15, 2015 black cotton soil black cotton soil has a tendency to shrink and swell excessively. The foundation should be taken at ieast 50 cm lower than the depth of moisture movement. The construction of foundation for structure on black cotton soils poses a challenge to the. Mr mburu notes that while you can easily build on red soil which requires minimum excavation while setting up the foundation, black cotton soil. Hence foundation in black cotton soil need special care.
This alternate process of swelling and shrinking results in the differential settlement of foundation which in turn causes cracks in building. Midwest naturalpave was specifically created to take advantage of native soils. This is the ultimate bearing capacity of soil shown in table. It results into cracks in foundations wall and roof. Study of suitable foundations for black cotton soil ijraset. Search for solutions to problems black cotton soils. Usually, the technology provides an alternative provision structural solution to practical problema. This article provides study notes on black cotton soil.
For more information about types of foundation i encourage you guys to buy this book. Apart from this black cotton soil should be removed from the sides of the foundation and filled with sand and gravel. Civil engineering world a learning platform for the civil. In black cotton soils, safe bearing capacity of the soils is taken as a 5 kgcm2 b 2. Expansive soils, popularly known as black cotton soils in india are, amongst the most problematic soils from civil engineering construction point of view. May 07, 2016 the treatment of black cotton soil with bagasse ash at 16% by dry weight of soil has given a cbr value as high as 11. When these type of soil come in contact with water, they swell and when becomes dry, it shrinks. Black soil is also known as black cotton soil as cotton is an important crop which is grown in this type of soil. The design foundation on black cotton soil expansive soil has always been a difficult task for the engineers as the structure resting on black cotton soil cracks without any warning. Criteria for the selection of type of foundation happho. What are the problems of foundation on black cotton soil. The possibility of good construction sites to build structures on black cotton soils is difficult due to their poor.
Jul 14, 2015 this is used at locations where sub soil water table is met within 0. Dividing the ultimate soil bearing capacity by a safety factor we get the maximum safe bearing capacity of soil for design of foundations. Black cotton soil black cotton soil has a tendency to shrink and swell excessively. Soil stabilization aims at improving soil strength and increasing resistance to softening by water through bonding the soil particles together, water proofing the particles or combination of the two sherwood, 1993. Black cotton soil, a cohesive soil, is considered a problematic soil for civil engineers. Building a foundation in black cotton soil is a risk and to avoid the risk, read here which will reveal the mystery of foundation in black cotton soil. Analysis of engineering properties of black cotton soil. Suitability of foundation on the basis of soil type clayey soils laterite soils and black cotton soil have high clay content. Bearing capacity of soil is the maximum load per unit area. House construction cost calculator excel sheet free download. The optimum dosage of bagasse ash in stabilizing black cotton soil is 16% by dry weight of the soil. Selfploughing is a characteristic of the black soil as it develops wide cracks when dried.
Jul 15, 2017 black cotton soils also called regur soils are generally clayey, deep and impermeable. Minutes of the proceedings of the institution of civil engineers. Sep 16, 2014 this video is about my residential site under reamed pile foundation process in black cotton soil. The possibility of good construction sites to build structures on black cotton soils is difficult due to their poor strength and deformation characteristics. For such a soils the geotech engineers have got a solution in the form of a specially designed pile foundation called underreamed pile foundation. Of the various factors that affect the swelling behaviour of these soils, the basic mineralogical composition is very important.
What are bearing capacity values of different types of soil. Black cotton soil has a tendency to shrink and swell excessively. What are the difference between clay and black cotton soil. Characteristics of black cotton soil with cement dust and lime3,6 bc soil is considered as a very poor type of soil having black colour with very fine grain. This type of soil contains pure clay particles with about 85100 percentages passing through 75 micron sieve. Atterberg limits tested in laboratory is tabulated in table1. Swells and will become sticky when wet and shrink when dried. Pdf design of pile foundation in black cotton soil. Pdf geotechnical investigation of black cotton soils. Pdf design of pile foundation in black cotton soil ijirst. Study notes on black cotton soil building engineering. Jan 09, 2016 black cotton soil, a cohesive soil, is considered a problematic soil for civil engineers.
These soils expand and become sticky during rainy season and contract during the dry season causing deep cracks into the soil. Foundations in black cotton soils the construction civil. Loose fine sand, soft silt, black cotton soil and expensive clays should be avoided for foundation. It has characteristics of swelling during rains and shrinking during summer. The mat foundation is suitable for black cottonexpansive soils whose bearing capacity is less for suitability of spread footings and wall footings. Major soil types of india geologically, indian soils can broadly be divided into soils of peninsular india and soils of extrapeninsular india. In both the world reference base for soil resources wrb and the usda soil taxonomy, a vertisol vertosol in the australian soil classification is a soil in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. Black cotton soils foundation process in hyderabad youtube.
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