Abstract
The interlayer shear weakness zone (ISWZ) is a deformation zone in stratified rock masses, with different width and spacing, due to tectonic stresses. It represents the main flow path in rocks due to higher permeability compared with massive rocks. The permeability values of an ISWZ can vary significantly depending on the scale. This study focuses on the correlations between the permeability properties of ISWZs and their geometry properties. A range of realistic 3-D numerical models of ISWZs is developed using geostatistical modeling, with fine-scale geometry and permeability information taken into consideration. These ISWZs represent a set of mud content and width distributions that are typical for ISWZs. Horizontal and vertical permeability values for all ISWZs are found to change in small-scale samples, whereas these fluctuations decrease with increasing sample size. For different types of ISWZs, the results show that ISWZs with variable width will show a significantly larger scale effect on the permeability than that of ISWZs with constant width. Furthermore, ISWZs with a higher mud content display greater variation in horizontal permeability, while the opposite is true for vertical permeability. Based on the coefficient of permeability variation, a criterion is proposed to identify the calculated permeability of a sample is locally homogeneous. The size for this sample relies on the properties estimated (horizontal and vertical permeability) and geometry features. These findings could provide a basis for the selection of permeability values of an ISWZ in hydraulic engineering. Additionally, the procedures used in this article can be applied to any type of ISWZs.
Highlights
IntroductionMost rocks possess discontinuities (such as fractures, faults and shear zones) which facilitate groundwater flow through them
Most rocks possess discontinuities which facilitate groundwater flow through them
20 steps shown in Figure 6, in order to study how permeability varies with scale, sample from the smallest scale
Summary
Most rocks possess discontinuities (such as fractures, faults and shear zones) which facilitate groundwater flow through them. Some discontinuities (such as faults and dykes) may act as a barrier to fluid flow [1]. The permeability characteristics of rocks depend on both the intact rock formations and their discontinuities [2,3,4]. It is extremely important to quantify the hydrogeological properties of discontinuities in rocks. As regards volcanic rock masses, individual strata of basalt resulting from multiple distinct eruptions may be interlayered with tuffs. Where tectonics stresses the masses, brittle shear planes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
