Research on Targeted Survey of Fractured Rock Mass in Deep and Long Tunnels Using CSAMT
Due to the large depth,extended length,and complicated and varying geological conditions of deep and long railway tunnels,it is difficult to achieve a clear and detailed geological survey.In particular,the precise location of the spatial distribution of fractured rock mass in deep and long tunnels always remains a challenge in engineering surveys.Based on the CSAMT 3D forward modeling and inversion theory,a targeted survey approach for fractured rock mass in deep and long tunnels was established to achieve precise"point-line-plane"surveys.The study verified the benefits of utilizing 3D CSAMT for railway tunnel surveys by conducting research on CSAMT 3D forward modeling based on tetrahedral mesh and 3D inversion employing the limited-memory quasi-Newton method,as well as analyses and comparisons between 2D and 3D models.A 3D"point-line-plane"targeted survey test was carried out in the TBM tunneling work area of a deep and long tunnel in western Yunnan.The results show that this survey system is reliable and can achieve high precision.It ascertained the influence range and spatial distribution pattern of the granite alteration zone in front of the work area where the TBM was stuck and determined the influence range and spatial distribution pattern of the fractured fault zone,thereby effectively improving the survey precision of the deep and long tunnel.The concept of arranging targeted survey lines to carry out 3D CSAMT"point-line-plane"surveys provides practical significance for surveys of deep and long tunnels.
CSAMTdeep and long tunnelsfractured rock masstargeted survey system
NETL
NSTL
万方数据
