FE studies were done in an FEI Strata 235 Dual Beam FIB (DB-FIB) with a vacuum better than 10−5 Torr.
First, a dual beam FEI Strata 400 (FEI, Hillsboro, OR, USA), a focused ion beam (FIB) coupled to a scanning electron microscopy (SEM) system, has been used.
Based on the surrounding rock deformation and instability feature of longwall mining working face with super cutting height, we establish the roof strata "cantilever + voussoir beam" structural mechanics model and rib "tension-slippage" coupling mechanical model (Pang and Wang 2017a, b), as shown in Fig. 4.
The 'dry' skin (epidermis + dermis) of ~1 mm thickness was cut into a circular shape of ~25 mm diameter and glued onto the cylindrical cell with the stratum corneum layer facing the laser beam.
The limit span of the key strata can be calculated based on the beam model.
Based on the study discussed above, a "cantilever beam articulated beam" structural model for overlying strata at a LLTCC face has been developed, shown in Fig. 9.
The approach, in which nominally planar processing is used, derives mechanical robustness from a naturally diffuse interface between the beam-damaged stratum and the adjacent unmodified shape-memory layer.
Strata-tunnel -fault can be considered as a beam on an elastic foundation.
(2) A "cantilever beam-articulated beam" model has been established for the overlying strata at the LLTCC coal mining face.
These folds result in a beam of collimated incident radiation passing through the stratum corneum to be refracted and become more diffuse [ 16].
Identifiable structural loading arising, for example, from crane tracks can be supported on reinforced-concrete beams on piles driven through the filling to the strata beneath.
