轴向应力加卸载过程含瓦斯水合物煤体渗透率变化规律研究  

Permeability of mine gas hydrate bonded coal against loading-unloading of axialstress

作　　者：张保勇 于洋 高霞 吴强 张旭辉[3] 张强 李焕如 ZHANG Baoyong;YU Yang;GAO Xia;WU Qiang;ZHANG Xuhui;ZHANG Qiang;LI Huanru(School of Safety Engineering,Heilongjiang University of Science and Technology,Harbin,Heilongjiang 150022,China;School of Architecture and Civil Engineering,Heilongjiang University of Science and Technology,Harbin,Heilongjiang 150022,China;Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]黑龙江科技大学安全工程学院,黑龙江哈尔滨150022 [2]黑龙江科技大学建筑工程学院,黑龙江哈尔滨150022 [3]中国科学院力学研究所,北京100190

出　　处：《岩石力学与工程学报》2022年第11期2283-2298,共16页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(51974112,51674108);国家自然基金联合基金项目(U21A20111)。

摘　　要：瓦斯水合固化及采掘扰动对瓦斯水合物–煤体介质体系渗透率影响是瓦斯水合固化防突技术应用的关键问题。为此,采用基于出口端流量的稳态法,利用应力–渗流–化学耦合作用含瓦斯水合物煤体三轴试验机,开展含瓦斯煤体渗透试验(3种含水率和3种粒度)及轴向应力加卸载过程含瓦斯水合物煤体渗透试验,分析水合物生成、加卸载过程有效应力及饱和度对煤体渗透率影响规律并初步探讨其影响机制。研究发现,瓦斯水合物形成后,煤体渗透率明显下降,降低幅度为79%~99%;含瓦斯水合物煤体渗透率与有效应力在加卸载过程符合指数函数关系,卸载过程渗透率变化存在3种模式,分别为少量恢复、部分恢复和卸载增透;加卸载过程含瓦斯水合物煤体渗透率损失率、损伤率均随饱和度增大呈增大趋势。试验发现,瓦斯水合物的形成堵塞煤体渗透通道,限制由瓦斯压力降低导致的瓦斯运移补充,有望快速降低瓦斯压力,缩短石门揭煤工期。Key issues still remain in revealing the effect of hydrate formation on coal permeability,as well as the permeability variation subjected to mining exploitation,concerning to the application of the hydrate method.Using steady-state method based on outlet flow,the permeability tests of gas-bearing coal(three water contents and three particle sizes)and subsequently the tests of mine gas hydrate bonded coal for against loading-unloading of axial stresses were conducted,by triaxial testing machine for coupled seepage,chemical and triaxial stress measurements in mine gas hydrate bonded coal.Then,the rule and mechanism are revealed relating to the effect of hydrate formation,effective stress and hydrate saturation on coal permeability.The results show that the coal permeability decreases after hydrate formation by a reduction between 79%and 99%.The permeability varies exponentially with the effective stress under loading-unloading of axial stresses.The variation of the permeability under unloading can be divided into three patterns,including a small amount of permeability recovery,partial permeability recovery and permeability increase.In the process of loading-unloading of axial stress,the permeability loss rate and damage rate increase with the growth in the hydrate saturation for mine gas hydrate bonded coal.As a result,the formation of gas hydrate blocks the coal penetration channel and restricts the coal mine gas migration,which makes it a possible solution to shortening the construction period of rock cross-cut coal,accompanied by gas pressure decrease in a short time.

关 键 词：采矿工程 煤与瓦斯突出 含瓦斯水合物煤体 渗透率 加卸载 饱和度 

分 类 号：TD32[矿业工程—矿井建设]