江西井冈山鹅岭隧道的工程地质调查与涌水量预测

摘要

江西井冈山鹅岭隧道是新建衡阳—茶陵—吉安铁路的关键性控制工程,洞身全长10455 m,最大埋深750 m.该隧道的地质构造复杂,断裂发育,岩石破碎,水量丰富.其涌水量是该隧道设计和施工的重要参数.在区域地质和构造调查的基础上,本研究选择不同渗水岩性段进行了多口钻井(DK)及其水文地质试验,获得了一批宝贵的第一手隧道工程地质和水文地质资料和数据.通过对这些资料和数据的分析和研究,确定了不同地质体的出水量和渗透系数.继而,按钻井位置将该隧道划分为9个不同涌水区段,运用不同方法对各个区段的涌水量进行了精细计算,预测5个区段涌水量大,分别为DK7+280—DK7+550(最大赋水段)、DK6+625—DK7+280(中等赋水段)、DK8+875—DK10+085(中等赋水段)、DK11+570—DK11+770(中等赋水段)和DK13+570—DK13+930(中等赋水段),施工过程中很可能产生突发涌水现象,建议施工设计中采取有效防护措施,高度重视这些区段的工程质量.实践证明,本文的研究结果对嗣后的该隧道设计和施工发挥了积极的指导作用,提高了施工质量.%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.