Compression modulus Es is one of the physical and mechanical
indexes of soil, and it is also an important index for foundation settlement
calculation. The traditional method is to give the curve e-p for manual search [p1,
p2] and[e1, e2], then calculate the compression coefficient av=-Δe/Δp, and then
calculate the compression modulus Esv=(1+e0)/av. In this paper, cubic spline
function is established by using experimental data (p, ln(h)). On this basis, the
APP program is compiled with Android MFP language as a tool to calculate the
tangent compression modulus Es of any point and secant compression modulus
Esv of any interval on the mobile phone.