I am looking for a geotechnical design software which has the capacity to model FRP composite sheet pile wall for shoreline protection. I would appreciate any suggestion you can provide.
You can use any software to solve your problem. But to do that you must be able (as you correctly mentioned in you question) to model FRP composite sheet. However, if you want to receive the real and useful results from your analysis, this will be possible only if you, first, carry out experimental investigations on the specimens and then apply your data to describe the behavior of FRP composite sheet and then to model it in your analysis.
Depends upon the complexity of the project. Simple free programs for conventional sheet pile work but you need to be highly focused on the lower strength and modulus of the sheet pile. Once you get into multiple tie backs it is best to model in non sheet pile software.
you do it easily by Plaxis software but first, it is better if you get soil parameters from the laboratory and get the interface friction angle between FRP and soil then it can be simulated easily in Plaxis.