Input : Alignment tunnel information, ring information and settlement instrument

Output : Prediction settlement due to single tunnel ring excavation

S = v * e^(-y^2 / 2i^2) * (g(xi) – g(xf)) / √(2 * π * i^2)

v = π/4 * d^2 * VL

xi = DL + HD

xf = xi – (RD * j * Tdir)

If k not specified:

k = GL – Tdist

x = distance (m)

y = settlement (mm) -> uses settlement from volume formula

GL = Ground Level (m)

Tdist = Tunnel Distance (m)

DL = Distance from start of Line (m)

HD = Tunnel Head Distance (m)

RD = Ring Distance (m)

j = point index of distance from head (m)

Tdir = Tunnel Direction <-> 1 or -1

g(x) = gaussian function applied to x

z0 = depth (m)

y = distance (m)