English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

This paper considers dynamic fracturing of the rockmass surrounding a tunnelstatically loaded by compressional stress as a possible source of seismicevents in underground mines. This begins with two-dimensional dynamic modellingof failure for six plausible scenarios. In each case, the seismic sourcederived from these models has significant negative isotropic and negativecompensated linear vector dipole components as well as a P-axis approximatelyaligned with the direction of maximum compressional principal stress. Thesefeatures indicate that at wavelengths larger than the diameter of the tunneland the extent of damage along it, seismic radiation is controlled by theelastic convergence of the surrounding rockmass rather than by rock fracturing.An analytical approximation of the source mechanism is suggested that is basedsolely on mechanical and geometric properties: the magnitudes$\sigma_{\mathrm{max}}$ and $\sigma_{\mathrm{min}}$ of the maximum and minimumprincipal stresses orthogonal to the tunnel's axis, the Poisson's ratio $\nu$of the rockmass, the length $L_{3}$ of dynamic fracturing along the tunnel, theeffective tunnel dimension $\bar{L_{A}}$, and the increase in depth of failure$\triangle d_{f}^{A}$ in the direction of $\sigma_{\mathrm{min}}$. Furthermore,it is shown that the scalar seismic moment can be approximated as$|\mathbf{M}|\approx2[(1-\nu)/(1-2\nu)]|\sigma_{max}|L_{3}\bar{L_{A}}\triangled_{f}^{A}$. The suggested approximations are considered in the context ofseismic data from a real underground mine. It is shown that many mechanismsinverted from observed waveforms are consistent with the suggested model andthat the proposed source mechanism approximation can be used for the forensicanalysis of damaging seismic events and quantitative monitoring of theevolution of fractured zones around tunnels.

Description of seismic sources in underground mines: Dynamic stress fracturing around tunnels and strainbursting