Abstract:

The Eling Tunnel, with a length of 10455 m and a maximum depth of 750 m, is located in the Jinggangshan area,
Southern Jiangxi Province. It is a key engineering structure along the newly built railway from Hengyang to Chalin and to Jian.
Folding and fracturing structures through the Eling Tunnel are considerably complex and brittle fractures such as joints and
cleavages are commonly filled with water. The water inflow is a key engineering parameter for the design and construction of
a tunnel. On the basis of regional-scale engineering geological and structural investigation, several petrological domains with
different degrees of water penetration were used to test the drilling-wells and hydrological geology. By means of aforesaid work,
abundant first-hand data of tunnel engineering and hydrological geological condition were obtained. The authors carefully
analyzed these data related to the tunnel engineering, and identified important parameters for each petrological domain including
water inflow (m3/d.km) and penetrating-water factor (m/d.km). Then, we divided the tunnel into nine sub-blocks according to

the survey of geological engineering and hydrological geology. The amounts of water inflow for nine sub-blocks were precisely
calculated using different methods and formulas. The results indicate that the five sub-blocks, including DK6+625 to DK7+280
(middle water inflow), DK7+280 to DK7+550 (maximal water inflow), DK8+875 to DK10+085 (middle water inflow), DK11+570
to DK11+770 (middle water inflow) and DK 13+570 to DK13+930 (middle water inflow), are of high water inflow, probably
causing the paroxysmal water inflow disaster during the construction of tunnel. Thus we suggest that in the tunnel design stage,
available safeguard mesurkes such as bracket should be seriously considered, and the quality of tunnel engineering must be
closely monitored, sub-block by sub-block, during construction. Practical work demonstrated that the aforementioned results have
an indispensable and forecast value for the design and construction of the Eling Tunnel.

Key words: engineering geology, water inflow, Eling Tunnel, Jinggangshan of Jiangxi Province