To develop suitable soil testing devices and soil testing methods. A database of 641 fall cone tests on 101 soil samples from 12 countries has been analysed to determine the best mathematical relationship linking undrained shear strength with liquidity index. Haigh abstract a database of 641 fall cone tests on 101 soil samples from twelve countries has been analysed to determine the best mathematical relationship linking undrained shear strength with liquidity index. Article pdf available in canadian geotechnical journal 519. Pdf some recent developments in the determination of the. The value of plasticity index ip and liquidity index il of north. The liquidity index il determines the consistency and physical state of soil. From the database, it is shown that the use of a linear relationship linking liquidity index and the logarithm of undrained shear strength that uses the commonly assumed 100fold factor increase in strength from the liquid to plastic limit overpredicts the measured data of soil strength. Atterbergs limits are very important in soil mechanics to know about the properties and behaviour of soil atterbergs limits tests, liquid limit, plastic limit soil mechanics atterbergs limits, soil mechanics, liquid limit, plastic limit, shrinkage, liquidity, flow index, tougness index.
The liquid limit ll of a soil is defined as the moisture content above which the soil behaves as a liquid, and the plastic limit pl is the moisture content above which the soil behaves plastically. Soil mechanics and foundation engineering multiple choice questions. Students conducted two trials and found that pl 17. In each state, the consistency and behavior of a soil is different and consequently so are its engineering properties.
When the soil is at the plastic limit, its liquidity index is zero. From figure 2, noting that e wgs, water content is expressed as a percentage a. The water content at which the soil changes from one state to the other are known as consistency limits or atterbergs limits. The test results were presented graphically by plotting the liquidity index against the logarithm of the undrained shear strength.
U uplift force due to seepage on the same volume of soil 2 w d. Some basic properties like the plasticity index, the liquidity index, and the activity of a soil are introduced and. The moisture content at this boundary is arbitrarily defined as the water content at which two halves of a soil cake will flow together, for a distance of. The water content of a given soil, along with its liquid and plastic limits as determined by test method d 4318, is used to express its relative consistency or liquidity index. The lack of availability of higher quality materials and the added costs for these. Consistency index is directly related to liquidity index. Toughness index is defined as the ratio of a plasticity index to consistency index b plasticity index to flow index c liquidity index to flow index d consistency index to liquidity index ans. During atterberg limit tests in the soil mechanics. It is used to describe the firmness of soil consistency is used only for clays 8 2014 iit bombay, ce 303, dc 4 lambe and whitman 2 82014 atterberg. If the plasticity index of a soil mass is zero, the soil is a sand. Soil surveys can provide a great deal of valuable geotechnical information in rural and agricultural areas. Geotechnical and foundation formula sheet table contents page. In comparison with the result obatined using the bjerrums correction factor, the undrained shear strength was better represented when s u values were correlated with the liquidity index.
From figure 2, noting that e wgs, water content is expressed as a percentage and su. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids usually air and water and particles usually clay, silt, sand, and gravel but soil may also contain organic solids and other matter. Example calculate activity of soil and liquidity index. It is the maximum water content at which a reduction in water content will not cause a decrease in volume of the soil mass. To investigate the physical properties of soil and. Pdf soil mechanics i lecture6 sushant singh academia. To collect and classify soils and their physical properties on the basis of fundamental knowledge of soil mechanics. Comparison of basic laboratory test results with more. Liquidity index indicates the nearness of its water content to its liquid limit. Nevertheless knowledge of mechanistic behavior of treated soil is equally important as selecting the stabilizer. The liquidity index li is used for scaling the natural water content of a soil sample to the limits.
In many projects only basic soil parameters such as index properties of soils are determined. From these observations we can see liquidity index of soil begins from zero at plastic limit and with increase in the water content soil s liquidity index increases and becomes 1 at liquid limit. Geotechnical engineering behavior of biopolymertreated soft marine soil. General particle size and its role in influencing properties plasticity and atterberg limits liquidity index of clay and relative density of sand sens. In soil mechanics the atterberg limits are the most distinctive and the easiest property of finegrained soils to measure. Some observations considering undrained shear strength, liquidity. Interpretation of geotechnical properties of cement.
To develop rational soil sampling devices and soil sampling methods. Negative values of the liquidity index indicate water content smaller than the plastic. If the plasticity index of a soil mass is zero, the soil is a sand b silt c clay d clayey silt ans. However, there is no empirical information about this relation. Consistency or liquidity index of soil the construction. It is the lowest water content at which soil can still be saturated. They, together with natural water content, are essential descriptions of finegrained soils. The liquidity index scales soil moisture content relative to plasticity, so that its value is 0.
Pdf the undrained strength liquidity index relationship. In finegrained cohesive soils, the consistency of a given soil type depends on its water content. Aug 31, 2014 b plasticity index to flow index c liquidity index to flow index d consistency index to liquidity index ans. The undrained strength liquidity index relationship. The correlation of index properties with some basic.
The liquidity index makes possible an evaluation of the consolidation degree of clays. May 05, 2015 the liquidity index li is used for scaling the natural water content of a soil sample to the limits. A negative consistency index indicates that the soil has a natural water content greater than the liquid limit and hence behaves just like a liquid. One of the most pressing needs for research in the geotechnical area is on the issue of the use of marginal soils e. Consistency index relative consistency, liquidity index, toughness index. Assessment of using liquidity index for the approximation of. The atterberg limits are found for remoulded soil samples. An effective substitute for liquidity index for prediction of shear strength of clays. It can be calculated as a ratio of difference between natural water content, plastic limit, and liquid limit. Residual soils are formed by a glaciers b wind c water d none of the above a soil mechanics and foundation engineering questions answers pdf free download for freshers civil engineering.
Introduction to soil mechanics geotechnical engineering. Soil mechanics terzaghi stated in his book theoretical soil mechanics 1943. Chapter 6 engineering properties of soil and rock nysdot geotechnical page 66 june 17, 20 design manual 6. Some of the correlations are also given in design manuals such as nav fac d7 nav fac 1986. The choice and effectiveness of an additive depends on the type of soil and its field conditions.
Manual on estimating soil properties for foundation design. This study first presents a critical examination of the use of various additives on soil improvement projects. Interpretation of geotechnical properties of cement treated soils. Atterberg limits soil classification liquid limit, plastic. Evaluation of shear strength of clayey soils by using.
In this study, clayey soil samples have been collected from various locations and tested. The relative consistency of a fine grained soil in the original state can be defined by a proportion called as liquidity index. The effect of soil plasticity on undrained shear strength was examined using the liquidity index instead of bjerrums correction factor. Some recent developments in the determination of the atterberg limits. The numerical difference between the liquid limit and plastic limit is termed the plasticity index pi. When the soil is at its liquid limit, its liquidity index is 100% and it behaves as a liquid. The atterberg limits are a basic measure of the critical water contents of a finegrained soil. The liquidity index i l or li provides a quantitative measure of the current state. As they depend on the same physical factors as the other mechanical properties of soils, the values of the liquid and plastic limits would be a very convenient basis for their prediction. We can notice if a soil is in plastic state then its liquidity index varies from 0 to 1.
Fang, soils engineer, aasho road test, highway research board this paper presents a new approach to liquid limit determ inations by a onepoint procedure. The development of soil mechanics in sweden, 19001925. Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. Logarithmic liquidity index is examined and found to also correlate strongly with the.
Soil mechanics arnold verruijt delft university of technology, 2001, 2006 this is the screen version of the book soil mechanics, used at the delft university of technology. Jan 23, 2017 ceen 341 lecture 4 atterberg limits and soil consistency office hours. The admixture of coarser particles like sand or silt to clay causes a decrease in liquid limit and increase in. The relative consistency of a cohesive soil in a natural state can be def ined by the ratio called li. Liquidity index soil moisture content plastic limit. Determine the liquidity index of the soil if the in situ moisture content is 21%. These limits as such do not indicate the consistency of undisturbed soil. Soil mechanics index properties and classification with respect to engineering behavior, consistency is the most important characteristics of cohesive soils. Here, the term li is the liquidity index, w is sample water content, pl will be standing for plastic limit and liquid limit indicated through ll. Consistency or liquidity index of soil the construction civil. Rapid determination of liquid limit of soils by flow index method. The index to indicate consistency of undisturbed soils is called liquidity index of the soil or water plasticity ration of the soil.
Ceen 341 lecture 4 atterberg limits and soil consistency. Basically in soil mechanics properties of soil are. Combining these assumptions with ideas of critical state soil mechanics it is then possible to relate the compression index of the remoulded soil to its plasticity index, and to suggest a unique relation between remoulded strength and liquidity index, irrespective of actual values of liquid and plastic limits. It refers to the strength and resistance to penetration of the soil in its inplace condition.
The undrained strength liquidity index relationship canadian. Ceen 341 lecture 4 atterberg limits and soil consistency office hours. Particle size and its role in influencing properties. Necessary equations, charts and tables, developed on the aasho road test and. In fine soils, especially clays, the current state is dependent on the water content with respect to the consistency limits or atterberg limits. Crash course for civil engineering students to understand the concepts and basic terminologies used in soil mechanics. Soil mechanics and foundations muni budhu download. Consistency or liquidity index of soil li it is defined as the natural moisture content of the soil in excess of the fl expressed as a percentage of the pl, i. Read more soil mechanics and foundation engineering questions. The author explains basic concepts and fundamental principles in the context of basic mechanics, physics, and mathematics. Basic index tests, soil classification and description. The undrained strength liquidity index relationship p. During atterberg limit tests in the soil mechanics laboratory, the students obtained the following results from a clayey soil. Rapid determination of liquid limit of soils by flow index.
Conference on soil mechanics and foundation engineering, stockholm, vollj\le 2, 489496. Geotechnical investigations are very important since they provide significant information about vari ous physical and mechanical soil properties which affect the. Plasticity index, ip, percent soft and stiff clays, and shale compositions c lay miner s f oc data from table 3 nc values of friction angle f for natural clay compositions nc for spsn range of 10 to 20 for spsn range of 2 to 5 sp 4100 kpa c c 3000 2000 1 0 0 2000 4000 6000 8000 s h e a r s t r e s s, k p a sn effective normal stress. Liquid limit, ll liquid limit is the water content of soil in which soil grains are separated by water just enough for the soil mass to loss shear strength. Rapid determination of liquid limit of soils by flow index method h. Liquidity index of clay and relative density of sand. The tests include the determination of liquidity index and shear strength. The liquidity index or waterplasticity ratio is the ratio, expressed as a percentage, of the natural water content of a soil minus its plastic limit, to its plasticity index. If consistency index is less than zero, then soil is in liquid state.