\chapter{Use of the D-Geo Stability Kernel 18.1} \label{sec:UseStabKernel}

For stabilily calculation the DAM engine uses the kernel used by D-Geo Stability 18.1
This use is restricted to the options described in this chapter.

\section{Model}\label{sec:Model}
The DAM Engine must be able to make calculations with following models:
		\begin{itemize}
		\item Bishop
		\item LiftVan (Uplift Van in D-Geostability)
		\item Horizontal balance
	\end{itemize}
	
All models are available for inwards stability. For outward stability only Bishop is used.
	
The choice of the model is a demand of the client:\\
DAM Client can demand Bishop, Uplift Van or combination Bishop/Uplift Van.\\
	
\subsection{Combination Bishop/Uplift Van}
\label{sec:CombinationBishopUpliftVan}

The combination Bishop/Uplift Van gives three results:
\begin{enumerate}
	\item Bishop
	\item Uplift Van\newline
	The client provides a requested uplift safety.	The UpliftVan calculation is made when this requested uplift safety factor is lower than the calculated uplift safety factor (for definition see \autoref {sec:UpliftCalculation}). Otherwise the result is 'not calculated'.
	\item Normative result (lowest safety factor) of both.
\end{enumerate}

\section{Slip plane definition and calculation area}\label{sec:PlaneDeinitionAndCalculationArea}
		
\subsection{Grid generation}
\label{sec:GridGeneration}
	
For the models Bishop and LiftVan a calculation grid must be generated.
There are two options:
\begin{enumerate}
	\item automatic generation
	\item user defined generation
\end{enumerate}

Ad 1 Automatic generation\newline
See FD of Macrostability kernel.

Ad 2 Client defined generation\newline
The client defines the dimensions; number of gridpoints and distance between the points. The \ProgramName defines the position of the grid depending on the characteristic points:
For Bishop and for the active grid of LiftVan the left (outside) bottom corner is situated at the surfaceline in the middle of the crest (distance between outer- and innercrest). The right bottom corner of the passive grid of LiftVan is situated above the most right x co-ordinate where uplift occurs. With the restriction that the left bottom corner can not be situated left of the x co-ordinate of the DikeToePolder.	
	
\subsection{Tangent lines generation}
\label{sec:TangentLinesGeneration}

For the Bishop model only automatic generation is used.\newline
The tangent lines are placed from the minimum Z-value of the surface line until 0.5 m below the upper geometry point of the lowest aquifer. The distance between the tangent lines is 0.25 m.

For LiftVan there are two client defined methods\newline
Distance defined - Naar opgave afstand\newline
For LiftVan the client must provide the distance between the tangent lines.
The lower tangent line is always situated 0.5 m below the boundary of the upper aquifer. The tangent lines are drawn with the given distance until the minimum Z value of the passive grid.\newline
On boundary - Op laagscheidingen (default)\newline
On every boundary of the subsoil layer.

\subsection{Calculation area}
\label{sec:CalculationArea}
For the model Horizontal balance a calculation area must be defined:
\begin{table*}[h]
	\centering
		\begin{tabular}{|p{50mm}|p{90mm}|} \hline
			\textbf{Parameter} & \textbf{Default value}\\ \hline
			X co-ordinate left side [m]& x co-ordinate DikeTopAtRiver\\ \hline
			X co-ordinate right side [m]& x co-ordinate DikeToeAtPolder\\ \hline
			Highest slip plane level [m]& Z value PL4 or PL3 (when one aquifer present) at x co-ordinate DikeToeAtRiver \\ \hline
			Lowest slip plane level [m]& Maximum Z value of top aquifer within calculation area\\ \hline
			Number of planes in the slip plane level [-]& 12\\ \hline
		\end{tabular}
	\caption{Calculation area for horizontal balance}
	\label{tab:CalcutlationArea}
\end{table*}


\section{Shear strength model}\label{sec:ShearStrengthModel}
The DAM engine must be able to make stability calculations with following shear strength models:
	\begin{itemize}
		\item C-Phi
		\item Stress tables
		\item	Cu calculated (with default inital surface level of D-Geo Stability; toplayer)
		\item Cu measured
		\item Cu gradient
		\item Pseudo values		
	\end{itemize}	
	This shear strength models are defined in the soil parameters per layer.

\section{Zone Plot}
\label{sec:Zoneplot}
The option of zone plot in D-Geo Stability is defined as the distinction of the slip circles in different zones; 1a, 1b, 2a, 2b, 3a and 3b, see manual D-Geo Stability.\newline
DAM only uses zone 1 and zone 2.
Zone Plot is used when\textsl{\textcolor[rgb]{0.65,0.16,0}{ZoneType}} = ZoneAreas

The following settings for the Zone plot of D-Geo Stability are used by DAM:\newline

\begin{itemize}
	\item Dike table heigth: user defined : \textcolor[rgb]{0.65,0.16,0}{\textsl{DikeTableHeight}} 
	\item Dike table width: 3 m
	\item Start x co-ordinate restprofile: Xlocal;DikeTopAtRiver
	\item Boundary of design level influence at x: Xlocal;DSurfaceLevelInside
	\item Boundary of design level influence at y: maximal Y co-ordinate of surface line
	\item Required safety in zones: \textsl{\textcolor[rgb]{0.65,0.16,0}{RequiredSafetyFactorStabilityInnerSlope}}
\end{itemize}
Calculation with zone areas is only possible for inward stability calculations.

\section{Calculation options}\label{sec:CalculationOptions}
D-Geostability offers different following calculation options. \ProgramName uses for the following settings the defaults of D-Geo Stability 18.1:
		
\begin{itemize}
	\item Requested number of slices: default D-Geo Stability
		\item Minimum slip plan length: default D-Geo Stability
	\item Start value safety factor: default D-Geo Stability
  \item Minimum x-entrance used: default D-Geo Stability
\end{itemize}

The following settings can be defined by the client:
\begin{itemize}
	\item Minimum circle depth
	\item Maximum x-entrance
\end{itemize}

The maximum x-entrance used is not directly client defined. The client provides a Forbidden zone and the \ProgramName calculates a maximum x-entrance via a method described in \autoref{sec:ForbiddenZone}.

\subsubsection{Forbidden zone }\label{sec:ForbiddenZone}
Forbidden zone is an option to define a forbidden zone for the entrance point of the slip plane.
The forbidden zone is situated to the rigth side of a certain x co-ordinate. This x co-ordinate is defined by the \textsl{ForbiddenZoneFactor}. Xlocal;forbidden zone WF =(Xlocal;DikeTopAtPolder) + ForbiddenZoneFactor*(Xlocal;DikeToeAtPolder - Xlocal;DikeTopAtPolder)
A forbidden zone is used when \textsl{ZoneType} = ForbiddenZone. 

\begin{table*}[h]
	\centering
		\begin{tabular}{|p{35mm}|p{75mm}|} \hline
			ForbiddenZonefactor & maximum x-entrance\\ \hline
			0 & x co-ordinate DikeTopAtPolder\\ \hline
			1 & x co-ordinate DikeToeAtPolder\\ \hline
		\end{tabular}
	\caption{Forbidden zone factor}
	\label{tab:ForbiddenZoneFactor}
\end{table*}

In a picture:

\begin{figure}[H]
	\centering
		\includegraphics[width=0.95\textwidth]{pictures/ForbiddenZoneFactor.png}
	\caption{Forbidden zone factor}
	\label{fig:ForbiddenZoneFactor}
\end{figure}

\section{Traffic load Degree of consolidation}\label{sec:TLDegOfCo}
The traffic load degree of consolidation is a material parameter. This may vary per location, per traffic load and hydraulic load. 
Therefore it must be possible to define the traffic load degree of consolidation per location.\newline
In the UI the import of the traffic load degree of consolidation is done per material via soilmaterials.mdb and per location via csv-file or shape-file.\newline
\newline
The hierarchy is:
\begin{enumerate}
	\item Traffic load degree of consolidation per material.\newline
	For material types peat, clay and loam overwritten by:
	\item Traffic load degree of consolidation per location.
\end{enumerate}

So the Traffic load degree of consolidation of the material types sand and gravel keep the value from soilmaterials.mdb.
