摘要
我国西部地区有丰富的煤炭资源埋藏在富水岩层下,普遍采用冻结法凿井实现井工开采。与我国中东部地区表土冻结不同的是,西部地区人工冻结的目标为富水岩层,其为孔隙储水、裂隙导水,易在裂隙处形成优势流。当出现裂隙优势流时,将不可避免地对岩体的冻结温度场产生控制性影响,裂隙面处往往会成为冻结壁的薄弱部位,这与表土冻结温度场研究中所考虑的孔隙渗流影响迥异。为此,本文在人工冻结温度场模型中引入裂隙参数和渗流参数,推导渗流裂隙岩体人工冻结水热耦合温度场的相似准则,并在此基础上开展裂隙岩体双管冻结温度场的模型试验和数值模拟研究。研究结果表明:裂隙渗流显著延缓了冻结壁交圈时间,裂隙面冻结壁交圈时间远大于岩块,且其冻结壁厚度也显著降低。在富水裂隙岩体人工冻结中,在冻结管与裂隙垂直,裂隙开度为20 mm,管间距为1.736 m时,冻结壁能够交圈的极限渗流速度为(17±1)m/d研究结果对西部地区富水岩层的冻结法凿井具有重要参考价值。
There is abundant coal resources buried in water-rich strata in Western China, and freezing method is widely used to drill wells to realize well mining. Different from the surface soil freezing in the middle and eastern part of China, the artificial freezing in the western part aims at water-rich rock strata, where pore water storage and fissure water conduction are adopted, and it is easy to form dominant flow in fissures and consequently leading to a controlling influence on the freezing temperature field of rock mass inevitably. Meanwhile, fracture surface will become the weak part of freezing wall, which is quite different from the pore seepage effect considered in the study of freezing temperature field of surface soil. In this paper, the similarity criterion of temperature field of artificial freezing in fractured rock mass is deduced by introducing fracture parameters and seepage parameters into the model of artificial freezing temperature field. On this basis, the model test and numerical simulation of double-pipe freezing temperature field in fractured rock mass are carried out. The results have shown that the time of freezing wall intersection is significantly delayed by fissure seepage. The time of freezing wall intersection on fissure surface is much longer than that of rock mass, and the thickness of freezing wall is also significantly reduced. In artificial freezing of water-rich fractured rock mass, when the freezing pipe is perpendicular to the fissure, the fissure opening is 20 mm and the pipe spacing is 1.736 m, the limit seepage velocity at which the freezing wall can intersect is(17±1) m/d. The research results have important reference value for freezing well sinking in water-rich strata in Western China.
作者
宋雷
王国柱
杨成立
韩立尚
李海鹏
杨维好
SONG Lei;WANG Guozhu;YANG Chengli;HAN Lishang;LI Haipeng;YANG Weihao(State Key Laboratory for Geomechanics and Deep Underground Engineering,School of Mechanics and Civil Engineering,China University of Mining&Technology,Xuzhou,Jiangsu 221116,China)
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2019年第6期1256-1263,共8页
Journal of Mining & Safety Engineering
基金
中央高校基本科研业务费项目(2018ZDPY0830)
国家重点基础研究发展计划(973)项目(2013CB227900)
关键词
渗流裂隙岩体
人工冻结温度场
模型试验
水热耦合
极限流速
seepage fissure rock mass
artificial freezing temperature field
model experiment
hydro-thermal coupling
limit velocity
