WASET
	@article{(Open Science Index):https://publications.waset.org/pdf/10007839,
	  title     = {Backward Erosion Piping through Vertically Layered Sands},
	  author    = {K. Vandenboer and  L. Dolphen and  A. Bezuijen},
	  country	= {},
	  institution	= {},
	  abstract     = {Backward erosion piping is an important failure mechanism for water-retaining structures, a phenomenon that results in the formation of shallow pipes at the interface of a sandy or silty foundation and a cohesive cover layer. This paper studies the effect of two soil types on backward erosion piping; both in case of a homogeneous sand layer, and in a vertically layered sand sample, where the pipe is forced to subsequently grow through the different layers. Two configurations with vertical sand layers are tested; they both result in wider pipes and higher critical gradients, thereby making this an interesting topic in research on measures to prevent backward erosion piping failures.},
	    journal   = {International Journal of Geotechnical and Geological Engineering},
	  volume    = {11},
	  number    = {9},
	  year      = {2017},
	  pages     = {766 - 769},
	  ee        = {https://publications.waset.org/pdf/10007839},
	  url   	= {https://publications.waset.org/vol/129},
	  bibsource = {https://publications.waset.org/},
	  issn  	= {eISSN: 1307-6892},
	  publisher = {World Academy of Science, Engineering and Technology},
	  index 	= {Open Science Index 129, 2017},
	}