Experimental Study of Seepage Properties of Broken Sandstone Under Different Porosities

• Published in: Transport in porous media Vol. 86; no. 3; pp. 805 - 814
• Main Authors: Miao, Xiexing, Li, Shuncai, Chen, Zhanqing, Liu, Weiqun
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.02.2011; Springer; Springer Nature B.V
• Subjects: Civil Engineering; Classical and Continuum Physics; Coal mines; Coefficients; Curve fitting; Disasters; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Geotechnical Engineering & Applied Earth Sciences; Grain size; Hydrocarbons; Hydrogeology; Hydrology. Hydrogeology; Hydrology/Water Resources; Industrial Chemistry/Chemical Engineering; Nonlinearity; Outbursts; Permeability; Pollution, environment geology; Porosity; Properties (attributes); Roads & highways; Rock; Sandstone; Sedimentary rocks; Seepage; Servocontrol; Stone; Variation; Water flow; Non-Darcy coefficient; Steady seepage; Broken sandstone; Permeability; Experimental study; experimental studies; permeability; sandstone; hydraulics; fluctuations; pore pressure; displacements; stability; clastic rocks; carbonaceous rocks; Non-Darcy coefficient β; porosity; resources; mining; seepage; transport; velocity; loading; water; sedimentary rocks; grain size; coal; compression; porous media; methodology
• ISSN: 0169-3913; 1573-1634
• DOI: 10.1007/s11242-010-9653-1

In coal mining the water flow in broken rock is a very common phenomenon. Study of seepage properties of broken rock is one of the basic subjects required in order to understand the stability of rock surrounding roadways, preventing disasters such as water inrush and gas outbursts and developing underground resources. So far, quantitative studies on the nonlinear seepage properties of broken sandstone under different porosities are not extensive in the research literature. In this article, by means of an electro-hydraulic servo-controlled test system (MTS815.02) and a patent seepage device, the seepage properties under different conditions of porosity were tested on broken sandstone of five different grain sizes. Based on the loading method of controlling the axial compression displacement and steady permeating method, we obtained curves of the relation of pore pressure with time, as well as the relation curves between the pore pressure gradient for steady seepage and velocity. Furthermore, we calculated the permeability k and non-Darcy coefficient β corresponding to different porosities by fitting these curves with the binomial expression. This study indicates that: (1) the seepage properties of broken sandstone are closely related to grain size, load levels, and porosity structure; (2) the permeability k decreases, while the coefficient β increases with a decrease in porosity φ , but both the k − φ and the β − φ curves show some local fluctuations; (3) the permeability k of the broken sandstone has a magnitude of 10 −14 –10 −12  m 2 , while the coefficient β ranges from 10 10 to 10 12  m −1 . The results obtained provide some information for further study of the nonlinear seepage behavior of broken rock theoretically.