the release of stress

Question

In plaixs2d, the release of stress can be set when the tunnel is excavated. How to realize it in plaxis3D ? 
 Thank you.

Dennis Waterman · Answer

Dear Xin Fang, 
 I presume you refer to something like the beta-method or deconfinement method in 2D? If so, those methods are to model the stress relaxation caused by the fact that in reality after the bore front the tunnel is unsupported over a certain distance before lining is applied. In 3D you don't need such method as you can really model the unsupported section. 
 With kind regards, 
 Dennis Waterman