隧道勘探中砂卵石地层钻进数值计算

Numerical Calculation of Sandstone Stratum Drilling in Tunnel Exploration

随着我国国民经济的迅速发展及其对交通建设的需求,隧道工程向长大深埋发展已成趋势,隧道勘探过程中遇到的问题也愈发复杂。采用k—ε湍流模型并通过商用数值软件模拟了砂卵石地层隧道勘探中反循环钻进过程,计算了不同岩屑大小、不同钻杆位置和不同排量条件下钻杆中岩屑体积分数分布及内钻杆流速。计算结果表明同一钻杆位置,3 mm岩屑在钻杆中的分布较1 mm岩屑要多,表明岩屑颗粒越小越容易排出,钻进也越容易。钻进过程中排量越大岩屑越容易排出,同一排量下,3 mm岩屑在钻杆中的分布较1 mm岩屑要多。钻杆底端钻头处内杆流速最小,距钻头0.5 m处存在波动,最终稳定在0.57 m/s左右工作。

With the rapid development of national economy of China and its demand for traffic construction,the development of tunnel works has become a trend,and the problems encountered in the tunnel exploration process are becoming more and more complicated. In this paper,the k — ε turbulence model is used to simulate the reverse circulation drilling process in the exploration of sand and gravel tunnel by a commercial numerical software,the distribution of cuttings in the drill pipe and the flow rate of the internal drill pipe are calculated according to the different cuttings size,different drill pipe position and different displacement conditions. The results show that the distribution of 3mm cuttings in the drill pipe is more than that of 1mm cuttings,indicating that the smaller the cuttings are,the easier it is to discharge and the easier the drilling. During the drilling process,the greater the displacement,the easier it is to discharge,With the same displacement,3 mm cuttings in the drill pipe in the distribution of more than 1mm cuttings. The minimum flow rate emerged at the bottom of the drill rod,0. 5 m away from the drill there is fluctuations,and ultimately stable at 0. 57 m/s.