function fs = factor_of_safety(c, h, theta, prock,m, phi) %fs = factor_of_safety(c, h, theta, prock,m, phi) %this function calculates the factor of safety for an infinite slope %stability problem. %See Arrowsmith notes %note that suggested units are in parenthesis below %JRA November 22,1999 % %Variables: % external % c = cohesion (kg m^-1 s^-2) % h = slide mass thickness (m) % theta = slope angle in degrees % prock = rock density (kg m^-3) % m = fraction of saturated thickness (such that m = 0 if the water % table is just below the slide surface and m = 1 if the % water table is at the ground surface) (dimensionless) % phi = angle of internal friction in degrees % % internal % g = gravitational acceleration (m s^-2) % pwater = water density (kg m^-3) % driving = driving stresses % resisting = resisting stresses %set up a couple of constants %others g = 9.81; pwater = 1000; %write the constants back to make sure that it looks right %fprintf('c = %.3f, h = %.3f, theta = %.3f, prock = %.3f, m = %.3f, phi = %.3f\n', c,h,theta,prock,m,phi); resisting = (c + h*g*(cos(rads(theta))^2)*(prock-(m*pwater))*tan(rads(phi))); driving = (prock*h*g*sin(rads(theta))*cos(rads(theta))); fs=resisting/driving;

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Prof. Ramón Arrowsmith

Last modified November 23, 1999