论文标题
地下地雷地震来源的描述：隧道周围的动态应力破裂
Description of seismic sources in underground mines: Dynamic stress fracturing around tunnels and strainbursting
论文作者
论文摘要
本文认为，由压缩应力静态负载的隧道周围的岩石质压裂是地下地雷地震事件的可能来源。这始于六个合理场景的失败的二维动态建模。在每种情况下，从这些模型中得出的地震来源都具有显着的负各向同性和负金额的线性载体偶极子成分以及与最大压缩原理应力方向相结合的P轴。这些特征表明，在大于隧道直径的波长以及沿隧道的损害程度的情况下，地震辐射受到周围岩浆的弹性收敛的控制，而不是通过岩石破裂。提出了仅基于机械和几何属性的来源机制的分析近似：幅度$σ_{\ Mathrm {max}} $和$σ_ {\ mathrm {mathrm {minrm {min}} $的最大和最大压力矫形器的最大和最大压力正孔的$ $ $ $ $ $ $ $ l_ {3} $沿隧道的动态压裂，有效的隧道维度$ \ bar {l_ {a}} $，以及失败的深度$ \ triangle d_ {f}^{f}^{a} $在$σ__{\ mathrm {minrm {min min} $的方向上。此外，结果表明，标量地震力矩可以被近似为$ | \ Mathbf {m} | \ oft2 [（1-ν）/（1-2ν）] |σ_{max} | l_ {3} \ bar {l_ {l_ {l_ {a}}} \ triangle d_}在来自真实地下矿山的地震数据的背景下，考虑了建议的近似值。结果表明，从观察到的波形反转的许多机制与建议的模型一致，并且建议的源机制近似可用于对破坏性地震事件的法医分析以及对隧道周围裂缝区域的演化的定量监测。
This paper considers dynamic fracturing of the rockmass surrounding a tunnel statically loaded by compressional stress as a possible source of seismic events in underground mines. This begins with two-dimensional dynamic modelling of failure for six plausible scenarios. In each case, the seismic source derived from these models has significant negative isotropic and negative compensated linear vector dipole components as well as a P-axis approximately aligned with the direction of maximum compressional principal stress. These features indicate that at wavelengths larger than the diameter of the tunnel and the extent of damage along it, seismic radiation is controlled by the elastic convergence of the surrounding rockmass rather than by rock fracturing. An analytical approximation of the source mechanism is suggested that is based solely on mechanical and geometric properties: the magnitudes $σ_{\mathrm{max}}$ and $σ_{\mathrm{min}}$ of the maximum and minimum principal stresses orthogonal to the tunnel's axis, the Poisson's ratio $ν$ of the rockmass, the length $L_{3}$ of dynamic fracturing along the tunnel, the effective tunnel dimension $\bar{L_{A}}$, and the increase in depth of failure $\triangle d_{f}^{A}$ in the direction of $σ_{\mathrm{min}}$. Furthermore, it is shown that the scalar seismic moment can be approximated as $|\mathbf{M}|\approx2[(1-ν)/(1-2ν)]|σ_{max}|L_{3}\bar{L_{A}}\triangle d_{f}^{A}$. The suggested approximations are considered in the context of seismic data from a real underground mine. It is shown that many mechanisms inverted from observed waveforms are consistent with the suggested model and that the proposed source mechanism approximation can be used for the forensic analysis of damaging seismic events and quantitative monitoring of the evolution of fractured zones around tunnels.
