5.4   Tension Cracks

  • Tension cracks can be modeled in MobiSlope below lines on the top surface of the slope geometry.
  • To include a tension crack in the analysis, tap the Select/Pan Tool in the Drawing tab of the tool palette, and tap once on a line on the top surface of the drawing geometry to select it. Red circles will be displayed at the line end points to indicate it is selected. Now press and hold over the selected line and a menu will be presented with the option to Set Tension Crack Zone. Select it.
  • A dialog will be presented allowing you to set the depth of the tension crack below the surface line, and the fluid level within the tension crack.
  • The fluid level must be a number between 0 (empty) and 1 (full) that represents the level of fluid within the crack that will exert a lateral force on the slice adjacent to the tension crack.
  • The area to the depth of the tension crack below the surface line will be shaded to indicate the presence of a tension crack in the drawing.
  • Tension cracks can be set below multiple surface lines.
  • When a slip surface encounters a tension crack area, the slip surface is projected vertically to the surface. This may occur at the beginning and end of the slip surface. See the Infinite Slope example for a case where two tension cracks are involved.
  • Once an analysis is complete, use the Inspector Tool and tap over a slice adjacent to the tension crack to view the slice forces and verify the lateral water force (if fluid level is greater than 0) has been modeled as expected.
  • To reset a tension crack, simply set the depth of the tension crack line to be 0 and it will be ignored.