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Hi, can anyone see why I am getting the error message '''Undefined Function or Variable R'' . As far as I understand I had already defined R...

Many thanks!

gamma = 15; % Unit weight, Kg/m^3

colRadius = 0.17; % Column Radiu, m

theta = 1*(180/pi); % Angle of failure to the horizaontal surface

phi = 15*(180/pi); % Angle of internal friction

depth = zeros(14,2); % Depth, m

for i = 1:19

depth(i,1)=i;

depth(i,2)=2.25+(0.5*i);

p(i,1) = gamma*depth(i,2)*((depth(i,2)/colRadius)^2+(3*(depth(i,2)/colRadius)*tan(theta))+(3*tan(theta)*tan(theta)))/(3*tan(theta)*tan(theta))*(1+(2*(1-sin(phi)*cos((180*(180/pi))-(theta+phi))))/(cos(phi*cos(theta))));

end

gamma = 15; % Unit weight, Kg/m^3

colRadius = 0.17; % Column Radiu, m

theta = 1*(180/pi); % Angle of failure to the horizaontal surface

phi = 15*(180/pi); % Angle of internal friction

E = 2 ; % Modulus of soil deformation, Kpa

n = 1; % Exponant in empirical equation

p = (200); % Applied pressure at the grout soil interface, kPa

c = 5% cohesion

Ri = 0.06; % Drill radius

Ir = 5 % Rigidity index of soil

v = 2 % Poisson's ratio

q = 2 % Initial Isotropic Ground Stress

a1 = ((1/Ir)-1+1*(-(1+v/2*E))*(4*sin(p)/3-sin(phi))*(q+c*cot(phi)))^3;

a2 = c*cot(phi);

a3 = (3*(1+sin(phi))/(3-sin(phi))*(q+c*cot(phi)));

a4 = (3*(1-sin(phi)))/(4*sin(phi));

a5 = (1/Ir);

try

R = (Ri/(a1(p+a2/a3)^a4)+(a3/p+a2)^a4)-a5^(1/3);

catch

end

figure;

hold on

plot(p,R)

xlabel('Injection Pressure (KPa)');

ylabel('Bulb Radius (kPa)');

Dimitris Kalogiros
on 3 Oct 2019

Edited: Dimitris Kalogiros
on 3 Oct 2019

I think there is a typo at the formula that calculates R :

Something is missing there. Maybe a + or * mark

By the way, calculation of R gives an error. Since you have enclose it inside "try-catch" , there is no variable R when the script is trying to plot it.

Correct the typo, remove try-catch and try again....

meghannmarie
on 3 Oct 2019

Edited: meghannmarie
on 3 Oct 2019

You are not setting R becuase you have it in a try catch block and it is throwing an error. That is because you are tryind to index a1, but are you really wanting to multiply a1?

Should:

R = (Ri/(al(p+a2/a3)^a4)+(a3/p+a2)^a4)-a5^(1/3)

actually be:

R = (Ri/(al*(p+a2/a3)^a4)+(a3/p+a2)^a4)-a5^1/3

Steven Lord
on 3 Oct 2019

meghanmarie had flagged this answer:

It marked my answer as spam and it is not

I had marked the answer not spam and I am removing the flag.

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