Firstly

based on the basic characteristic curves and revealed by the results of the soil dynamic tests

the rules of adjustable double-parabola constitutive curves of reverse unload after load process or reverse load after unload process in irregular load history are established

and function implementation and implement of A type and B type parabola are expounded for the characteristics of reverse load or unload curves sometimes change more flatly at first and then acutely. Secondly

by comparisons of 9 methods simulated results of soil test damping

the load and unload rules of double-parabola model accord with the test results

especially accord with the value of soil test damping

and they can be regarded as the simplification and practicality of generalized Masing rule. Because of the adjustment coefficient can be changed

the model has more powerful capability of simulation the shape of constitutive relationship curves. At last

using the borehole array records of Taiwan Lotung DHB field test

the nonlinear seismic response of DHB site are analyzed by equivalent linear method SHAKE91

LSSRLI-1

nonlinear method in time domain- DESRA-2

Pyke model

Non-Masing rule model ONE

implicit stress damping equivalent model

damping degradation coefficient model

Non-Masing rule model TWO and double-parabola constitutive model respectively. After compared all the synthesizing acceleration ground motions with the observation records

we found the PGA of double-parabola model are almost equal to the observation value

the comparative size relations of waveform

subsequence waveform are agree well with the records. As a result

the rationality of double-parabola constitutive model and the feasibility in practical engineering application are manifested.