Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/SoilProfile/MacroStabilityInwardsSoilProfileUnderSurfaceLine.cs
===================================================================
diff -u -rf2838b78c54529e9b15208b44de854f7760e350f -r90a9502badff5788374461a1b2179a5dd0e866a2
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/SoilProfile/MacroStabilityInwardsSoilProfileUnderSurfaceLine.cs	(.../MacroStabilityInwardsSoilProfileUnderSurfaceLine.cs)	(revision f2838b78c54529e9b15208b44de854f7760e350f)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/SoilProfile/MacroStabilityInwardsSoilProfileUnderSurfaceLine.cs	(.../MacroStabilityInwardsSoilProfileUnderSurfaceLine.cs)	(revision 90a9502badff5788374461a1b2179a5dd0e866a2)
@@ -21,22 +21,23 @@
 
 using System;
 using System.Collections.Generic;
+using Ringtoets.MacroStabilityInwards.Primitives;
 
 namespace Ringtoets.MacroStabilityInwards.Data.SoilProfile
 {
     /// <summary>
     /// A soil profile for which its properties have been adapted using a surface line.
     /// </summary>
-    public class MacroStabilityInwardsSoilProfileUnderSurfaceLine
+    public class MacroStabilityInwardsSoilProfileUnderSurfaceLine : IMacroStabilityInwardsSoilProfileUnderSurfaceLine
     {
         /// <summary>
         /// Creates a new instance of <see cref="MacroStabilityInwardsSoilProfileUnderSurfaceLine"/>.
         /// </summary>
         /// <param name="layers">The layers in the profile.</param>
         /// <param name="preconsolidationStresses">The preconsolidation stresses defined for the profile.</param>
         /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
-        public MacroStabilityInwardsSoilProfileUnderSurfaceLine(IEnumerable<MacroStabilityInwardsSoilLayerUnderSurfaceLine> layers,
-                                                                IEnumerable<MacroStabilityInwardsPreconsolidationStress> preconsolidationStresses)
+        public MacroStabilityInwardsSoilProfileUnderSurfaceLine(IEnumerable<IMacroStabilityInwardsSoilLayerUnderSurfaceLine> layers,
+                                                                IEnumerable<IMacroStabilityInwardsPreconsolidationStress> preconsolidationStresses)
         {
             if (layers == null)
             {
@@ -49,15 +50,9 @@
             Layers = layers;
             PreconsolidationStresses = preconsolidationStresses;
         }
+        
+        public IEnumerable<IMacroStabilityInwardsSoilLayerUnderSurfaceLine> Layers { get; }
 
-        /// <summary>
-        /// Gets the layers in the profile.
-        /// </summary>
-        public IEnumerable<MacroStabilityInwardsSoilLayerUnderSurfaceLine> Layers { get; }
-
-        /// <summary>
-        /// Gets the preconsolidation stresses in the profile.
-        /// </summary>
-        public IEnumerable<MacroStabilityInwardsPreconsolidationStress> PreconsolidationStresses { get; }
+        public IEnumerable<IMacroStabilityInwardsPreconsolidationStress> PreconsolidationStresses { get; }
     }
 }
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