  We perform simulations of the dust and gas disk evolution to investigate the
observational features of a dust-pileup at the dead-zone inner edge. We show
that the total mass of accumulated dust particles is sensitive to the
turbulence strength in the dead zone, $\alpha_{\rm dead}$, because of the
combined effect of turbulence-induced particle fragmentation (which suppresses
particle radial drift) and turbulent diffusion. For a typical critical
fragmentation velocity of silicate dust particles of $1~{\rm m~s^{-1}}$, the
stress to pressure ratio $\alpha_{\rm dead}$ needs to be lower than $3 \times
10^{-4}$ for dust trapping to operate. The obtained dust distribution is
postprocessed using the radiative transfer code RADMC-3D to simulate infrared
scattered-light images of the inner part of protoplanetary disks with a dust
pileup. We find that a dust pileup at the dead-zone inner edge, if present,
casts a shadow extending out to $\sim 10~{\rm au}$. In the shadowed region the
temperature significantly drops, which in some cases yields even multiple water
snow lines. We also find that even without a dust pileup at the dead-zone inner
edge, the disk surface can become thermally unstable, and the excited waves can
naturally produce shadows and ring-like structures in observed images. This
mechanism might account for the ring-like structures seen in the
scattered-light images of some disks, such as the TW Hya disk.
