Mathematical Problems in Engineering / 2019 / Article / Fig 6

Research Article

Evaluation of Ground Surface Pregrouting in a Mountain Tunnel Based on FAHP

Figure 6

Schematic of the test of ultrasonic waves.

(a) Single-borehole test
(b) Double-borehole test

We are committed to sharing findings related to COVID-19 as quickly and safely as possible. Any author submitting a COVID-19 paper should notify us at to ensure their research is fast-tracked and made available on a preprint server as soon as possible. We will be providing unlimited waivers of publication charges for accepted articles related to COVID-19. Sign up here as a reviewer to help fast-track new submissions.