ABSTRACT
Design of underground structures requires prediction of the response to service loading conditions. Two techniques can be employed in predicting structure behavior: numerical analyses based on theoretical models, and laboratory testing of scaled models of structures. The second method is the subject of this chapter. It is a viable technique for predicting the response of specific structures to load, as well as qualifying numerical codes. Physical modeling of a structure for laboratory testing may involve either or both material and dimensional modeling. Dimensional modeling of a structure generally consists of reducing the dimensions but using the same host material as the prototype structure. When the prototype material cannot be used, a simulant material has to be developed which satisfies the similitude laws for the prototype material. The radial crown-invert and springline tunnel deformations were measured using Linear Variable Displacement Transducers. For the straight tunnels, the tunnel closures were measured at one diameter intervals from the block center.
