D60: Fill & Download for Free

Nearly 120 years ago a guy named Allen Hazen set out on a goal to identify, from a soil mass, the particular size/diameter of soil grains that can be used to speculate various properties of the whole soil mass.ALLEN HAZEN (1869-1930)He conducted several experiments on filter sand and found that the diameter he was looking for was D10, which is a diameter just larger than the diameters of 10% of the soil grains, in other words, it's the size of the sieve through which only 10% of the soil grains pass.He discovered that this diameter can be related to most of the soil properties such as liquid limit, plasticity index, unconfined compressive strength, etc and hence can be used to empirically calculate those properties.The famous use being the classification of soil and the determination of coefficient of permeability.Uniformity coefficient, Cu = D60/D10Coefficient of curvature, Cc = (D30)^2/(D60.D10)Hazen's permeability coefficient k (in cm/s) = 100(D10)^2In the view of these impressive findings, Hazen naturally called this diameter - equivalent/effective diameter.TL;DR: Short answer for viva -It was found from several experiments that diameter D10 is more representational of the properties of the soil sample than any other diameter and hence more useful and accurate in calculating those properties. Therefore, it's called equivalent/effective diameter.

It is regarded as one of the most valuable chart in the horoscope. It truly reflects a human being.The method of preparations of this chart is similar to how we prepare D9 or D7. In case the exact time of the person is not sure, then the astrologer should not opt for D60 chart. In D60 chart, the lagna changes every two minutes, so if you are not aware of specific time, avoid D60.Astrologers (learned) often refers to D60 charts, and most of them also give huge priority to D60 chart.The analysis of this chart is done in the same say, as we refer to Main lagna chart. however we use different dasha system to predict from D60.

First, let us take a look at this grain size distribution curve.In this curve,x axis - Particle size(dia) in mm in log scaley axis - Percentage finer.From this curve, we can find the D60, D30 and D10 of a particular soil.D60 - 60 % of the soil particles are finer than this size.D30 - 30% of the particles are finer than this size.D10 - 10% of the particles are finer than this size.Above definitions are just self explanatory. For example, if you have 100 particles of diameter ranging from 1 mm to 100 mm, D60 is 61 mm (below which 60% of particles are there).Why do we find this?To find Cu and Cc.Cu - Uniformity coefficient.Cu = D60/D10.Cc - Coefficient of curvature.Cc = (D30)^2 /(D60)(D10).What is the use of this Cu and Cc?Cu is always greater than 1 (equal to 1 is possible only by theoretical). If Cu is closer to 1 ( ie. D60 and D10 sizes are close to each other, which means there are more no. of particles are in the same size range), the soil is considered as uniformly graded.If Cu is away from 1, the soil is well graded(ie. it has a vareity of size range distributed well). For gravel, if Cu>4, it is well graded. For sand, if Cu>6, it is well graded.Cc is also greater than 1 ( equal to 1 is possible only by theoretical). For a well graded soil, Cc ranges between 1 to 3.So,Cu and Cc gives us idea about particle size distribution of a soil. These values are used in the soil classification.Bonus points :Why log scale is used instead of normal scale? If we use normal scale, it requires veryyyy length sheet to plot the soil size. Soil particles sizes ranges from few micrometers to centimeters range( 10^(-6) to 10^(-2) m ). So, it is impossible to cover this range with normal scale. Hence, log scale is used. And also getting a good curve is possible only with log scale.For a uniformly graded soil, the grain distribution curve is almost vertical. For a well graded soil, the curve has a good slope. For a gap graded soil, the curve is almost horizontal in between any two points.