Abstract:
The uncertainties of soil shear modulus reduction (
G/
Gmax) and damping (
λ) increase curves with shear strain amplitude (
γa) have important influence on the uncertainty of the results of nonlinear site seismic response. Based on the test data of undisturbed marine silty clay samples taken from seabed surface to 110 m depth at the Laizhou Bay, the
G/
Gmax curve is described using the Davidenkov skeleton curve function, and the
λ curve is expressed as a function of two variables, i.e., the
λmin (small strain damping) and
G/
Gmax. The laboratory investigation reveals that the prediction equations of parameters
A,
B, and
γr, which describe the
G/
Gmax curve and
λmin, are all functions of the seabed depth
H. The uncertainty transfer analysis based on point estimation method shows that the total uncertainty of the predicted
G/
Gmax caused by the parameters
A,
B, and
γr and the single univariate uncertainty of the predicted
G/
Gmax caused by one of the three parameters increase first and then decrease with
γa. The total and univariate uncertainty of the predicted
G/
Gmax caused by the variable
B or
γr decrease with
H, whereas the univariate uncertainty of the predicted
G/
Gmax caused by the variable
A increases with
H. The total uncertainty of the predicted
λ caused by
G/
Gmax and
λmin and the univariate uncertainty of the predicted
λ caused by
G/
Gmax increase slightly first and then decrease slightly with
γa, while both decrease slightly with
H. The univariate uncertainty of the predicted
λ caused by
λmin is independent of
γa and increases slightly with
H.