Index: DamClients/DamPythonInterface/trunk/src/tests/test_data/test_segment.xml
===================================================================
diff -u
--- DamClients/DamPythonInterface/trunk/src/tests/test_data/test_segment.xml	(revision 0)
+++ DamClients/DamPythonInterface/trunk/src/tests/test_data/test_segment.xml	(revision 3491)
@@ -0,0 +1,4 @@
+<Segment Name="Test segment">
+  <SoilGeometryProbability SoilProfileName="soilprofile_01" SoilProfileType="0" SegmentFailureMechanismType="1" Probability="1.0"/>
+  <SoilGeometryProbability SoilProfileName="soilprofile_01" SoilProfileType="0" SegmentFailureMechanismType="2" Probability="1.0"/>
+</Segment>
Index: DamClients/DamPythonInterface/trunk/src/tests/test_output/test_full_output.xml
===================================================================
diff -u -r3490 -r3491
--- DamClients/DamPythonInterface/trunk/src/tests/test_output/test_full_output.xml	(.../test_full_output.xml)	(revision 3490)
+++ DamClients/DamPythonInterface/trunk/src/tests/test_output/test_full_output.xml	(.../test_full_output.xml)	(revision 3491)
@@ -33,6 +33,12 @@
       </Layers1D>
     </SoilProfile1D>
   </SoilProfiles1D>
+  <Elements>
+    <Segment Name="Test segment">
+      <SoilGeometryProbability SoilProfileName="Soil profile" SoilProfileType="0" SegmentFailureMechanismType="1" Probability="1.0"/>
+      <SoilGeometryProbability SoilProfileName="Soil profile" SoilProfileType="0" SegmentFailureMechanismType="2" Probability="1.0"/>
+    </Segment>
+  </Elements>
   <StabilityParameters SearchMethod="0" GridDetermination="0" BishopTangentLinesDefinition="0" BishopTangentLinesDistance="0.25" BishopGridVerticalPointsCount="10" BishopGridVerticalPointsDistance="2.5" BishopGridHorizontalPointsCount="10" BishopGridHorizontalPointsDistance="2.5" UpliftVanGridLeftVerticalPointsCount="1" UpliftVanGridLeftVerticalPointsDistance="1" UpliftVanGridLeftHorizontalPointsCount="1" UpliftVanGridLeftHorizontalPointsDistance="1" UpliftVanGridRightVerticalPointsCount="1" UpliftVanGridRightVerticalPointsDistance="1" UpliftVanGridRightHorizontalPointsCount="1" UpliftVanGridRightHorizontalPointsDistance="1" UpliftVanTangentLinesDefinition="0" UpliftVanTangentLinesDistance="1"/>
   <AquiferSoils>
     <AquiferSoil Soilname="soil 1" IsAquifer="true"/>
Index: DamClients/DamPythonInterface/trunk/src/dampythoninterface/segment.py
===================================================================
diff -u
--- DamClients/DamPythonInterface/trunk/src/dampythoninterface/segment.py	(revision 0)
+++ DamClients/DamPythonInterface/trunk/src/dampythoninterface/segment.py	(revision 3491)
@@ -0,0 +1,104 @@
+# Copyright (C) Stichting Deltares 2021. All rights reserved.
+#
+# This file is part of the Dam Python Interface.
+#
+# The Dam Python Interface is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+# All names, logos, and references to "Deltares" are registered trademarks of
+# Stichting Deltares and remain full property of Stichting Deltares at all times.
+# All rights reserved.
+
+from typing import List, Optional
+import lxml.etree as et
+from enum import IntEnum
+
+from .base_class import BaseDataClass
+
+
+class SoilProfileTypeClass(IntEnum):
+    """ """
+
+    ProfileType1D = 0
+    ProfileType2D = 1
+    ProfileTypeStiFile = 2
+
+
+class SegmentFailureMechanismTypeClass(IntEnum):
+    """ """
+
+    All = 0
+    Stability = 1
+    Piping = 2
+    Liquefaction = 3
+
+
+class SoilGeometryProbabilityElement(BaseDataClass):
+    """
+    Dataclass that contains the propability and the failure mechanism type of an occuring profile.
+
+    :param SoilProfileName: name of the selected soil profile
+    :param SoilProfileType: geometry type of the selected soil profile
+    :param SegmentFailureMechanismType: type of failure mechanism selected for a profile
+    :param Probability: probability of selected geometry
+
+    """
+
+    SoilProfileName: str
+    SoilProfileType: SoilProfileTypeClass
+    SegmentFailureMechanismType: Optional[
+        SegmentFailureMechanismTypeClass
+    ] = SegmentFailureMechanismTypeClass.Stability
+    Probability: float
+
+    def serialize(self) -> et.Element:
+        """Function that serializes the SoilGeometryProbabilityElement dataclass."""
+        soil_geometry_probability_root = et.Element("SoilGeometryProbability")
+        dictionary_of_values = self.dict()
+        soil_geometry_probability_root.set(
+            "SoilProfileName", dictionary_of_values.get("SoilProfileName")
+        )
+        soil_geometry_probability_root.set(
+            "SoilProfileType",
+            str(dictionary_of_values.get("SoilProfileType").value),
+        )
+        soil_geometry_probability_root.set(
+            "SegmentFailureMechanismType",
+            str(dictionary_of_values.get("SegmentFailureMechanismType").value),
+        )
+        soil_geometry_probability_root.set(
+            "Probability", str(dictionary_of_values.get("Probability"))
+        )
+        return soil_geometry_probability_root
+
+
+class Segment(BaseDataClass):
+    """
+    Dataclass for a segment
+
+    :param Name: name of the segment
+    :param SoilGeometryProbability: List of SoilGeometryProbabilityElement
+
+    """
+
+    Name: str
+    SoilGeometryProbability: List[SoilGeometryProbabilityElement] = []
+
+    def serialize(self) -> et.Element:
+        """Function that serializes the Segment dataclass."""
+        segment_root = et.Element("Segment")
+        dictionary_of_values = self.dict()
+        segment_root.set("Name", dictionary_of_values.get("Name"))
+        for soilgeometry in self.SoilGeometryProbability:
+            segment_root.append(soilgeometry.serialize())
+        return segment_root
Index: DamClients/DamPythonInterface/trunk/doc/source/dev/input.rst
===================================================================
diff -u -r3490 -r3491
--- DamClients/DamPythonInterface/trunk/doc/source/dev/input.rst	(.../input.rst)	(revision 3490)
+++ DamClients/DamPythonInterface/trunk/doc/source/dev/input.rst	(.../input.rst)	(revision 3491)
@@ -43,4 +43,13 @@
 
 .. automodule:: dampythoninterface.soilprofile1D
     :members:
+    :undoc-members:
+
+
+Segment
+-------
+
+
+.. automodule:: dampythoninterface.segment
+    :members:
     :undoc-members:
\ No newline at end of file
Index: DamClients/DamPythonInterface/trunk/src/dampythoninterface/input.py
===================================================================
diff -u -r3490 -r3491
--- DamClients/DamPythonInterface/trunk/src/dampythoninterface/input.py	(.../input.py)	(revision 3490)
+++ DamClients/DamPythonInterface/trunk/src/dampythoninterface/input.py	(.../input.py)	(revision 3491)
@@ -30,6 +30,7 @@
 from .base_class import BaseDataClass
 from .stability_parameters import StabilityParameters
 from .soilprofile1D import SoilProfile1D
+from .segment import Segment
 
 
 class DamInput(BaseDataClass):
@@ -44,10 +45,11 @@
     Soils: List[Soil] = []
     StabilityParameters: StabilityParameters
     SoilProfiles1D: List[SoilProfile1D] = []
+    Segments: List[Segment] = []
 
     @validator("SoilProfiles1D")
     def soil_profiles_contain_soils(cls, v, values, **kwargs):
-        soils_names = [soil.Name for soil in values["Soils"]]
+        soils_names = [soil.Name for soil in values.get("Soils")]
         soilprofiles = v
         for soilprofile in soilprofiles:
             for layer in soilprofile.Layers1D:
@@ -59,6 +61,20 @@
                     )
         return v
 
+    @validator("Segments")
+    def segment_contains_existing_profile(cls, v, values, **kwargs):
+        profile_names = [profile.Name for profile in values.get("SoilProfiles1D")]
+        segments = v
+        for segment in segments:
+            for soilgeometry in segment.SoilGeometryProbability:
+                if not (soilgeometry.SoilProfileName in profile_names):
+                    raise ValueError(
+                        f"Profile {soilgeometry.SoilProfileName} \
+                        is part of segment {segment.Name} but not\
+                         part of the profile element."
+                    )
+        return v
+
     def ExportToXml(self, xml_file: Path) -> None:
         """
         Function that export the DamInput dataclass to an xml that can be used as input of the DAMengine.
@@ -82,6 +98,11 @@
         for soil_profile in self.SoilProfiles1D:
             soilprofiles_root.append(soil_profile.serialize())
         input_root.append(soilprofiles_root)
+        # add segments
+        segments_root = et.Element("Elements")
+        for segment in self.Segments:
+            segments_root.append(segment.serialize())
+        input_root.append(segments_root)
         # add stability parameters to input root
         input_root.append(self.StabilityParameters.serialize())
         # append soil aquifers
Index: DamClients/DamPythonInterface/trunk/src/tests/test_segment.py
===================================================================
diff -u
--- DamClients/DamPythonInterface/trunk/src/tests/test_segment.py	(revision 0)
+++ DamClients/DamPythonInterface/trunk/src/tests/test_segment.py	(revision 3491)
@@ -0,0 +1,80 @@
+# Copyright (C) Stichting Deltares 2021. All rights reserved.
+#
+# This file is part of the Dam Python Interface.
+#
+# The Dam Python Interface is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+# All names, logos, and references to "Deltares" are registered trademarks of
+# Stichting Deltares and remain full property of Stichting Deltares at all times.
+# All rights reserved.
+
+from dampythoninterface.segment import (
+    Segment,
+    SoilGeometryProbabilityElement,
+    SoilProfileTypeClass,
+    SegmentFailureMechanismTypeClass,
+)
+
+from .utils import TestUtils
+
+import pytest
+from pathlib import Path
+from lxml import etree
+
+
+class TestSegment:
+    def define_segment(self) -> Segment:
+        # first define the soil layers
+        profile_1 = SoilGeometryProbabilityElement(
+            SoilProfileName="soilprofile_01",
+            SoilProfileType=SoilProfileTypeClass.ProfileType1D,
+            Probability=1,
+            SegmentFailureMechanismType=SegmentFailureMechanismTypeClass.Stability,
+        )
+        profile_2 = SoilGeometryProbabilityElement(
+            SoilProfileName="soilprofile_01",
+            SoilProfileType=SoilProfileTypeClass.ProfileType1D,
+            Probability=1,
+            SegmentFailureMechanismType=SegmentFailureMechanismTypeClass.Piping,
+        )
+        return Segment(
+            Name="Test segment", SoilGeometryProbability=[profile_1, profile_2]
+        )
+
+    @pytest.mark.unittest
+    def test_if_segment_can_be_initialized(self):
+        segment = self.define_segment()
+        # test expectations
+        assert segment.Name == "Test segment"
+        assert len(segment.SoilGeometryProbability) == 2
+        assert segment.SoilGeometryProbability[-1].SoilProfileName == "soilprofile_01"
+
+    @pytest.mark.unittest
+    def test_serialize(self):
+        # initialize the stabilty parameters class
+        segment = self.define_segment()
+        # run test
+        root = segment.serialize()
+        # test output
+        xml_output = Path(TestUtils.get_output_test_data_dir(""), "test_segment.xml")
+        tree = etree.ElementTree(root)
+        tree.write(str(xml_output), pretty_print=True)
+        # get template file
+        xml_test_data = Path(
+            TestUtils.get_test_data_dir("", "test_data"),
+            "test_segment.xml",
+        )
+        # Line by line comparison
+        for output_file, test_file in zip(open(xml_output), open(xml_test_data)):
+            assert output_file.strip() == test_file.strip()
Index: DamClients/DamPythonInterface/trunk/src/tests/test_input.py
===================================================================
diff -u -r3490 -r3491
--- DamClients/DamPythonInterface/trunk/src/tests/test_input.py	(.../test_input.py)	(revision 3490)
+++ DamClients/DamPythonInterface/trunk/src/tests/test_input.py	(.../test_input.py)	(revision 3491)
@@ -34,6 +34,12 @@
     BishopTangentLinesDefinitionType,
     GridDeterminationType,
 )
+from dampythoninterface.segment import (
+    Segment,
+    SoilProfileTypeClass,
+    SoilGeometryProbabilityElement,
+    SegmentFailureMechanismTypeClass,
+)
 from dampythoninterface.soilprofile1D import (
     SoilProfile1D,
     Layer1D,
@@ -43,6 +49,24 @@
 
 
 class TestDamInput:
+    def define_segment(self, soil_profile_names: List[str]) -> List[Segment]:
+        # first define the soil layers
+        profile_1 = SoilGeometryProbabilityElement(
+            SoilProfileName=soil_profile_names[0],
+            SoilProfileType=SoilProfileTypeClass.ProfileType1D,
+            Probability=1,
+            SegmentFailureMechanismType=SegmentFailureMechanismTypeClass.Stability,
+        )
+        profile_2 = SoilGeometryProbabilityElement(
+            SoilProfileName=soil_profile_names[1],
+            SoilProfileType=SoilProfileTypeClass.ProfileType1D,
+            Probability=1,
+            SegmentFailureMechanismType=SegmentFailureMechanismTypeClass.Piping,
+        )
+        return [
+            Segment(Name="Test segment", SoilGeometryProbability=[profile_1, profile_2])
+        ]
+
     def create_surface_lines(self) -> List[SurfaceLine]:
         # Create surface lines
         points_available = [
@@ -121,19 +145,44 @@
         soils = self.create_soils()
         test_stabilty_parameters = self.create_stability_parameters()
         soil_profiles = self.create_profiles([soils[0].Name, "wrong soil name"])
+        segments = self.define_segment([soil_profiles[0].Name, soil_profiles[0].Name])
         # run test
         error_message = "Soil with name wrong soil name"
         with pytest.raises(ValueError) as e_info:
             DamInput(
                 SurfaceLines=list_of_surface_lines,
                 Soils=soils,
                 StabilityParameters=test_stabilty_parameters,
+                Segments=segments,
                 SoilProfiles1D=soil_profiles,
             )
         generated_error_message = str(e_info.value)
         assert error_message in generated_error_message
 
     @pytest.mark.integrationtest
+    def test_soil_profiles_contain_segments(self):
+        # Create surface lines
+        list_of_surface_lines = self.create_surface_lines()
+        # create soil class
+        soils = self.create_soils()
+        # Create stability parameters
+        test_stabilty_parameters = self.create_stability_parameters()
+        soil_profiles = self.create_profiles([soils[0].Name, soils[1].Name])
+        segments = self.define_segment([soil_profiles[0].Name, "Wrong profile"])
+        # run test
+        error_message = "Wrong profile"
+        with pytest.raises(ValueError) as e_info:
+            DamInput(
+                SurfaceLines=list_of_surface_lines,
+                Soils=soils,
+                StabilityParameters=test_stabilty_parameters,
+                SoilProfiles1D=soil_profiles,
+                Segments=segments,
+            )
+        generated_error_message = str(e_info.value)
+        assert error_message in generated_error_message
+
+    @pytest.mark.integrationtest
     def test_ExportToXml(self):
         # Create surface lines
         list_of_surface_lines = self.create_surface_lines()
@@ -142,12 +191,14 @@
         # Create stability parameters
         test_stabilty_parameters = self.create_stability_parameters()
         soil_profiles = self.create_profiles([soils[0].Name, soils[1].Name])
+        segments = self.define_segment([soil_profiles[0].Name, soil_profiles[0].Name])
         # Make input class
         model = DamInput(
             SurfaceLines=list_of_surface_lines,
             Soils=soils,
             StabilityParameters=test_stabilty_parameters,
             SoilProfiles1D=soil_profiles,
+            Segments=segments,
         )
         assert model
         # run test