On 11th Nov, an accurate breakthrough was achieved between south tunnel of Tongxin Section and north tunnel of Dexing Section in Tongjin Project. The successful breakthrough of haulage way creates favorable conditions for the future prospecting works and won high recognition from the client.
Since commencement in June 2011, it took totally 1960 days to complete the underground development and achieve this breakthrough. With 12368.799m / 170，000m3 tunnel development, direct horizontal distance of 5418.943m between two portals of declines, and total length of 4359.428m of breakthrough guide line, the project also faced multiple difficulties such as small sections in drifts, joint development, soft rocks, large water inflow, severe rock bursts, single heading development, poor ventilation, fractured zone, etc. JCHX adopted several measures such as sealed grouting, bolting with wire mesh, steel arch support to deal with aforementioned problems, thus leading to frequent processes shifts, difficulties in schedule arrangements, low efficiency in mucking and intensified labor requirements.
In order to ensure the accuracy of breakthrough, technicians made detailed work plan and conducted surveys, setting-outs in strict accordance to the plan and procedures, GPS control, gyro-compassing were adopted during re-measurement and correction. Meanwhile the management and HQ granted much support to this work.
