Relationship Between Void Ratio and Porosity
the porosity and void ratio both indicates the void hole in a soil mass but it a different as we discuss in three phase diagram👈 of volumetric relation. the voids ratio define how much voids present as compared to total solids in soil mass, where porosity say how much voids as compared to total volume of soil mass, in void ratio if the void increase in soil mass only top value change. but in porosity both top and bottom value change.👈 there is a relation between void ratio and porosity which very important in soil problem discuss below.
The relation between porosity and void ratio
we know formula of void ratio (e) = Vv / Vs
in which Vv = Volume of Voids and Vs = Volume of Solids
Porosity formula (n) = Vv / V
Vv = Volume of Voids and V= Total Volume of soil mass.
first letter V represent volume and second letter
a= air, W= water S= solid
also the volume of voids = Vw + Va
Now finding the relation between (e) and (n)
we know value of n, Firstly writes its
Now we reverse the equation by dividing by 1
total volume come upward due to divide
putting total volume V = Vv + Vs
now right side value may be written as shown, we get 2 value on the right side first one is same on lower and above so it gives 1.
Also we know Vv / Vs is void ratio and our value is just it reverse
putting e which divide by 1 so our value as according to the equation
star mark equation is most important you can find e from n and n from using this equation.
firstly finding e value from n
first transfer the 1 from the right side to the left side
then take l cm as shown in fig
the last step is lust reverse the value which give our final equation
we can also find an equation where n is find by e
just write the stat mark equation
an instant of transfer 1 toward left side this time
just take l cm of right side equation
now simply reverse the equation
and we ger a equation where you find porosity by using void ratio only.
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