The seepage characteristics of a single well dewatering from an unconfined aquifer bottom
-
摘要: 由含水层底部向上施工疏放水孔（井）进行疏水降压是保证煤矿安全开采的重要措施之一，该类疏放水孔与地面抽水井的渗流特征具有显著差别。为了研究井下疏放水孔的渗流特征，以非承压含水层底部单井疏放水孔为例，采用数值模拟的方法对其渗流特征进行研究。研究结果表明，当疏放水井的井长lw小于临界长度lc时，即lw<lc，疏放水井上部含水层孔隙水压力大于0，且由下而上呈先增加后减小的分布规律，渗流量与井长呈指数函数关系增加；当lw ≥ lc时，疏放水非完整井的渗流特征及渗流量与完整井相同；渗流量随井半径增加呈指数关系增加，且指数小于1；将s+lw代替水位降深s对裘布依（Dupuit）潜水完整井计算公式进行修正，当lw<lc时，采用修正的Dupuit潜水完整井计算公式计算疏放水非完整井渗流量更精确。该研究结果对认识井下疏放水井上部孔隙水压力分布特征及合理布置疏放水井具有重要的借鉴意义。Abstract: Dewatering from an aquifer bottom for drain and depressurization is one common method to ensure safety mining. This method is significantly different from pumping from the ground. In order to study the seepage characteristics of the dewatering hole(well), the seepage characteristics of a single well dewatering from an unconfined aquifer bottom was taken as an example and studied using numerical simulation method. The results show that when lw<lc, the pore water pressure above the dewatering well is greater than zero, which presents the rule of increasing first then decreasing from bottom to top, and the seepage flow increases with well length following an exponential function relationship. When lw ≥ lc, the seepage characteristics and seepage flow of the incomplete dewatering well is the same with the complete dewatering well. The seepage flow increases with the well radius following a power relationship with the exponent less than 1. By substituting s+lw into Dupuit formula for unconfined complete wells instead of drawdown s, a revised formula was proposed which could be used to calculate water flow for uncomplete dewatering wells with a more accurate result. This study will provide an important theoretical basis for understanding the seepage characteristics and more effectively drilling of the dewatering wells.
-
Keywords:
- aquifer /
- dewatering well /
- seepage flow /
- Dupuit formula
-
-
[1] Niskovskiy Y,Vasianovich A. Investigation of possibility to apply untraditional and ecologically good methods of coal mining under sea bed[C]//The Sixth International Offshore and Polar Engineering Conference. International Society of Offshore and Polar Engineers,1996,51-53.
[2] SUN Yajun,XU Zhimin,DONG Qinghong,et al. Forecasting water disaster for a coal mine under the Xiaolangdi reservoir[J]. Journal of China University of Mining and Technology,2008,18(4):516-520.
[3] ZHANG Jincai,SHEN Baohong. Coal mining under aquifers in China:A case study[J]. International Journal of Rock Mechanics and Mining Sciences,2004,41(4):629-639.
[4] LI Tie,MEI Tingting,SUN Xuehui,et al. A study on a water-inrush incident at Laohutai coalmine[J]. International Journal of Rock Mechanics and Mining Sciences,2013,59:151-159.
[5] 武雄,于青春,汪小刚,等. 地表水体下煤炭资源开采研究[J]. 岩石力学与工程学报,2006,25(5):1029-1036. WU Xiong,YU Qingchun,WANG Xiaogang,et al. Exploitation of coal resources under water body[J]. Chinese Journal of Rock Mechanics and Engineering,2006,25(5):1029-1036.
[6] 武强,赵苏启,董书宁,等. 煤矿防治水手册[M]. 北京:煤炭工业出版社,2013. [7] 方俊,张杰. 定向长钻孔超前疏放顶板水技术在枣泉煤矿的应用[J]. 煤炭工程,2016,48(7):56-59. FANG Jun,ZHANG Jie. Application of advance roof dewatering with directional long borehole in Zaoquan mine[J]. Coal Engineering,2016,48(7):56-59.
[8] HANG Yuan,ZHANG Gailing,YANG Guoyong. Numerical simulation of dewatering thick unconsolidated aquifers for safety of underground coal mining[J]. Mining Science and Technology(China),2009,19(3):312-316.
[9] 尹尚先,张祥维,徐慧,等. "大井法" 中渗透系数及含水层厚度的优化[J]. 煤田地质与勘探,2015,43(5):53-56. YIN Shangxian,ZHAGN Xiangwei,XU Hui,et al. Op-timization of permeability coefficient and aquifer thickness in large-well-method[J]. Coal Geology & Exploration,2015,43(5):53-56.
[10] 陈冲,李文尧,徐世光. 大井法在煤矿涌水量预测中的应用[J]. 煤炭技术,2017,36(11):199-201. CHEN Chong,LI Wenrao,XU Shiguang. Application of large diameter method in estimation water inflow of coal mine[J]. Coal Technology,2017,36(11):199-201.
[11] 李明山. 伯努利方程与井下探放水钻孔涌水量计算[J]. 矿业安全与环保,1999,26(2):37-38. LI Mingshan. Bernouli Equation and calculation of water inflow rate from probing and discharging[J]. Mining Safety & Environmental Protection,1999,26(2):37-38.
[12] 陈实,董书宁,李竞生,等. 煤矿工作面顶板倾斜钻孔疏放水井流计算方法[J]. 煤炭学报,2016,41(6):1517-1523. CHEN Shi,DONG Shuning,LI Jingsheng,et al. Analytical solution for slanted well in the roof of coal mine working face[J]. Journal of China Coal Society,2016,41(6):1517-1523.
[13] 赵宝峰. 灰色关联度在井下钻孔疏放水效果分析中的应用[J]. 辽宁工程技术大学学报(自然科学版),2013,32(3):289-292. ZHAO Baofeng. Application of gray correlation in the effect analysis of underground drilling water drainage[J]. Journal of Liaoning Technical University(Natural Science Edition),2013,32(3):289-292.
[14] 靳月灿,孙亚军,徐智敏,等. 收缩开采期封闭不良钻孔的涌水量预测研究[J]. 中国煤炭,2012,38(6):99-103. JIN Yuecan,SUN Yajun,XU Zhimin,et al. Research on water inflow prediction from bad sealed boreholes in contraction coal mining[J]. China Coal,2012,38(6):99-103.
[15] 王文学,隋旺华. 某矿第四系底部含水层降水井群优化布置[J]. 煤田地质与勘探,2011,39(2):30-33. WANG Wenxue,SUI Wanghua. Optimization for dewatering well design in the Quaternary bottom aquifer[J]. Coal Geology & Exploration,2011,39(2):30-33.
计量
- 文章访问数: 131
- HTML全文浏览量: 20
- PDF下载量: 9
下载:
