Introduction

Deltares Systems commitment to quality control and quality assurance has leaded them to develop a formal and extensive procedure to verify the correct working of all of their geotechnical engineering tools. An extensive range of benchmark checks have been developed to check the correct functioning of each tool. During product development these checks are run on a regular basis to verify the improved product. These benchmark checks are provided in the following sections, to allow the users to overview the checking procedure and verify for themselves the correct functioning of D-FLOW SLIDE.
The benchmarks for Deltares Systems are subdivided into five separate groups as described below:

• Group 1 – Benchmarks from literature (exact solution)
  Simple benchmarks for which an exact analytical result is available from literature.
• Group 2 – Benchmarks from literature (approximate solution)
  More complex benchmarks described in literature for which an approximate solution is known.
• Group 3 – Benchmarks from spreadsheets
  Benchmarks which test program features using Excel spreadsheets.
• Group 4 – Benchmarks generated by the program itself
  Benchmarks for which the reference results are generated using D-FLOW SLIDE.
• Group 5 – Benchmarks compared with other programs
  Benchmarks for which the results of D-FLOW SLIDE are compared with the results of other programs.

As much as software developers would wish they could, it is impossible to prove the correctness of any non-trivial program. Re-calculating all the benchmarks and making sure the results are as they should be will prove to some degree that the program works as it should. Nevertheless there will always be combinations of input values that will cause the program to crash or produce wrong results. Hopefully by using the verification procedure the number of times this occurs will be limited.
The benchmarks will all be described to such detail that reproduction is possible at any time. In some cases, when the geometry is too complex to describe, the input file of the benchmark is needed. The results are presented in text format with each benchmark description.
The input files belonging to the benchmarks can be downloaded from those pages.

Overview of the benchmarks

According to hand-calculation, the Advanced check passes but according to D-Flow Slide it fails.

Group 1: Benchmarks from literature (exact solution)

This section describes a number of benchmarks for which an exact analytical solution can be found in the literature.

Study Case described in "Technisch Rapport Voorland Zettingsvloeiing"

Description

The example given in "Annex A - Case Study" of the Deltares report 1200503-001-GEO-0004 "Concept Technisch Rapport Voorland Zettingsvloeiing" of G.A. van den Ham & Co is used.
In this example, both global and detailed checks are completed on the basis of a (fictitious) dike section, which with regard to geometry and soil structure is typical of the Southwest Delta.
The dike has a height of NAP+5 m and a crest width of 3 m.
The foreshore begins to imaginary toe of the dike at an elevation of NAP and is 60 m wide. The toe of the trench is NAP-15 m and has a slope of 1:6. The dike section is 800 m long.
The soil profile is as follows:

• from NAP+3.5 m to NAP+1 m: peat
• from NAP+1 m to NAP-5 m: silty clay
• from NAP-5 m to NAP-18 m: moderately to loosely compacted sand (Calais)
• from NAP-18 m to NAP-30 m: densely compacted sand

Benchmarks results

The details of the calculation can be found in annexe A of the report. The main results are given in the table below. The global check fails but the detailed check passes.

Description

Group 2: Benchmarks from literature (approximate solution)

This section uses the results of a by-hand calculation performed for three profiles of the Spui dike project (see figure below):

• hmp 63.9 (Nieuw Beijerland)
• hmp 65.0 (between Oud Beijerland and Nieuw Beijerland)
• hmp 67.8 (oud Beijerland)

XXX Insert figure

As the details of the calculation performed by hand are not available, those benchmarks are set in group 2.

hmp 63.9 (Nieuw Beijerland)

Description

The dike profile at hmp 63.9 is given in the figure below.
XXX Insert figure
The soil profile and the material properties are given in the following table:

Benchmark results

D-FLOW SLIDE results

hmp 65.0 (between Oud Beijerland and Nieuw Beijerland)

Description

Benchmark results

D-FLOW SLIDE results

hmp 67.8 (oud Beijerland)

Description

Benchmark results

D-FLOW SLIDE results

Group 3: Benchmarks from spreadsheets

This section contains tests that are missing in the other groups, for example for the CUR-113 method.

Group 5: Benchmarks compared with other programs

Comparison with SLIQ2D (Dos and Windows) - One fully saturated layer with variable slope angle

Description

The benchmarks in this paragraph are intended to verify the advanced method by comparing D-FLOW SLIDE results with those from the older program SLIQ-2D, using both DOS and Windows versions of this program.
Because of the limitations in the DOS version of SLIQ2D, only one fully saturated layer is inputted. The geometry and the material properties for each cases are given in the table below.
The original slope angle is 1:1.25 and is set to "variable" so that the program will search (for each point) for the most unfavorable slope.

Benchmark results

D-FLOW SLIDE results