摘要
针对深部岩土工程中的重大渗流迁移问题,中国科学院武汉岩土力学研究所自主研发了超长岩心侵蚀渗流试验装置(1500mm),其目的在于揭示各类流体在深部地层中的渗流机制。借助岩心侵蚀渗流试验装置,开展饱和卤水和气体在岩心(灰白色砂岩)中的渗流模拟研究,并建立渗流速度与渗透范围和压力梯度之间的通用数学模型。研究结果表明:在相同的温度(50℃)和应力边界(16 MPa)条件下,气体渗流速度极快,通过1000 mm的试样仅需12 s左右的时间,而卤水则需要大于1000 s,两者相差2个数量级。卤水和气体的渗流符合Darcy定律,数据拟合方程与理论公式极其吻合,相关性高达99.8%。卤水和气体的渗透范围与时间满足幂函数关系,表现为前期快速增长,后期平缓过渡并逐渐趋于稳定。而气驱卤水的渗透范围与时间并没确切的函数关系,它可近似为卤水和气体渗流的组合情况。此外,经卤水渗流后重结晶试样的渗透率和孔隙率普遍低于未结晶试样,这意味着盐晶体对多孔岩心具有一定的填充和密实作用。研究内容证实了长岩心侵蚀渗流试验装置可行性与实用性,为深部地层渗流提供了一种研究方法和思路,有助于揭示新的科学问题和解决实际工程难题。
Aiming at major seepage problems in deep geotechnical engineering,a seepage and erosion device with a maximum core length of 1500 mm was independently developed to reveal the seepage mechanisms of various fluids in deep strata,and seepage tests of saturated brine and gas in cores(off-white sandstone)were carried out.A general mathematical model describing the relationship among seepage velocity,seepage range and pressure gradient was established.The results demonstrate that,under the same temperature(50℃)and stress(16 MPa)condition,the seepage velocity of gas is extremely fast and about one hundred times of that of brine.The seepage of brine and gas is in accordance with Darcy’s law,and the test results are in good agreement with the theoretical calculations with a correlation coefficient of 99.8%.The relationship between the seepage range of brine and gas with time can be described by a power function,showing rapid growth in the early stage and gradual stabilization in the later stage.However,the seepage range of gas displace brine has no direct relation with time,which can be approximated as the combination of brine and gas seepage.In addition,the permeability and porosity of crystallized samples after brine seepage are lower than those of uncrystallized samples,which means that salt crystals have a certain filling and plugging effect on rock voids.This study confirms the feasibility and practicability of the developed device and provides a research method and idea for medium seepage in deep strata,which is helpful to reveal new scientific problems and to solve practical engineering problems.
作者
陈祥胜
李银平
施锡林
杨春和
杨杰
CHEN Xiangsheng;LI Yinping;SHI Xilin;YANG Chunhe;YANG Jie(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy and Sciences,Beijing 100049,China;Hubei Provincial Key Laboratory of Environmental Geotechnology,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;State Key Laboratory of Coal Mine Disaster Dynamics and Controls,Chongqing University,Chongqing 400044,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2019年第11期2254-2262,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点研发计划(2018YFC0808401)
国家自然科学基金资助项目(51874273,51774266)~~
关键词
岩石力学
渗流运移
压降曲线
渗透率
运动方程
rock mechanics
seepage and transport
pressure drop curve
permeability
motion equation
