Experimental investigation of initiation of backward erosion piping in soils

Experiments were conducted on field and laboratory-mixed soils in a new true-triaxial test apparatus to assess factors that influence initiation of piping in non-cohesive and cohesive soils. Three modes of piping behaviour were recognised: concentrated leak erosion, backward erosion, and suffusion. The amount and type of the fines present in the soils significantly influenced the initiation and mode of piping. The presence of non-plastic fines significantly reduced the required seepage velocity to initiate piping (critical seepage velocity), whereas the presence of plastic fines greatly increased the hydraulic gradient required to initiate piping. Concentrated leak erosion occurred along the soil/apparatus interface in soils with plastic fines at very low seepage velocity, but required very high hydraulic gradients. Backward erosion was the primary mode of failure in non-cohesive soils, and this mode required a seepage velocity of 0·8–1·1 cm/s to initiate piping in uniform sand. The critical seepage veloc...

[1]  Kevin S. Richards,et al.  Critical appraisal of piping phenomena in earth dams , 2007 .

[2]  M A Koenders,et al.  MATHEMATICAL MODEL FOR PIPING , 1992 .

[3]  R Fell,et al.  Investigation of internal erosion and piping of soils in embankment dams by the slot erosion test and the hole erosion test - interpretative report , 2002 .

[4]  R. Fell,et al.  The statistics of embankment dam failures and accidents , 2000 .

[5]  E. W. Lane,et al.  Closure of "Security from Under-Seepage-Masonry Dams on Earth Foundations" , 1935 .

[6]  A. Skempton,et al.  Experiments on piping in sandy gravels , 1994 .

[7]  Kevin Stank. Richards,et al.  Piping potential of unfiltered soils in existing levees and dams , 2008 .

[8]  Van Leuven,et al.  Assessing the potential for seepage barrier defects to propagate into seepage erosion mechanisms , 2011 .

[9]  Kevin S. Richards,et al.  Experimental Investigation of Piping Potential in Earthen Structures , 2008 .

[10]  K. Terzaghi,et al.  Der Grundbruch an Stauwerken und Seine Verhutung , 1922 .

[11]  J. B. Sellmeijer,et al.  On the mechanism of piping under impervious structures , 1988 .

[12]  D. Marot,et al.  A specific triaxial device for the study of internal erosion in cohesive soils , 2007 .

[13]  Mohan V. S. Bonala,et al.  Comparison of Internal and Surface Erosion Using Flow Pump Tests on a Sand-Kaolinite Mixture , 2000 .

[14]  Fateh Bendahmane,et al.  Experimental Parametric Study of Suffusion and Backward Erosion , 2008 .

[15]  John D. Rice,et al.  Deformation and Cracking of Seepage Barriers in Dams due to Changes in the Pore Pressure Regime , 2010 .

[16]  John F. Orwin,et al.  An inexpensive turbidimeter for monitoring suspended sediment , 2005 .

[17]  John H. Schmertmann,et al.  The No-Filter Factor of Safety Against Piping Through Sands , 2000 .

[18]  Kevin S. Richards,et al.  True triaxial piping test apparatus for evaluation of piping potential in earth structures , 2010 .

[19]  U. Schuler,et al.  Filters in Geotechnical and Hydraulic Engineering , 1993 .

[20]  G. Bertram,et al.  AN EXPERIMENTAL INVESTIGATION OF PROTECTIVE FILTERS , 1940 .

[21]  A. Anonymus.  Technical report on sand boils (piping) , 1999 .