CIVIL ENGINEERING AND GEOTECHNICAL CONSULTANTS LTD. · The program is based on the laws of motion...

DR. SPANG

Company: Register of Companies No. HRB 8527, District Court Bochum, VAT-Id. DE126873490, President Dipl.-Ing. Christian Spang

Main Office Witten: Westfalenstraße 5 - 9, D-58455 Witten, Tel. (23 02) 9 14 02 – 0, Fax (23 02) 9 14 02 – 20, [email protected], http://www.dr-spang.de Branch Offices: D-09596 Freiberg/Sachsen, Halsbrücker Str. 34, Tel. + Fax (37 31) 36 55 31, [email protected] D-73734 Esslingen/Neckar, Weilstr. 29, Tel. (07 11) 3513049-0, Fax (07 11) 35 130 49-19, [email protected] Bank Accounts: Stadtsparkasse Witten, Code 452 500 35 - Acc. No. 4911 - Deutsche Bank 24, Witten, Code 430 700 24 - Acc. No. 8139511

CIVIL ENGINEERING AND GEOTECHNICAL CONSULTANTS LTD.

Westfalenstr. 5-9, D-58455 Witten Tel. +49 (2302) 91402-0, Fax. +49 (2302) 91402-20

[email protected], http://www.dr-spang.de

- DEMOVERSION -

Rockfall Simulation Program ROCKFALL 7.1 Manual

DR. SPANG

Simulationsoftware ROCKFALL 7.1 2

Manual (release: March 2008)

ROCKFALL 7.1 is a computer program for the simulation of rockfall developed by Dr. rer. nat. R.M. Spang and Dr.-Ing. B. Romunde. The program is based on the laws of motion and the collision theory. The path of a single rock block or the paths of up to 10.000 blocks can be calculated and interpreted by the same run. At each point within a profile (especially at the positions of planned interception structures or rockfall barriers) the kinetic energies and bounce heights can be calculated. The input data are varied by a random number generator within user defined boundaries. The results are presented in class and summation histograms. ROCKFALL can be used for:

• Evaluation of the rockfall risk for slopes. • Assessment of the appropriateness of existing rockfall barriers. • Positioning of rockfall interception structures. • Optimization of the location and geometry of interception structures as for their height and

energy dissipation.

To ease access to program handling this copy includes several examples. During software installation these files are copied to your hard disc as:

• bsp1.prf • bsp2.prf • bsp3.prf • bsp4.prf • bsp5.prf • bsp6.prf

The handling of the program follows WINDOWS standards. Inputs can be done by menus and tables as well as by interactive graphical means. Basic tasks require a minimum of inputs and pre-settings. Tools for more complex tasks ease input and handling. Different print versions and export functions enable professional presentation of results. Thus reports can be prepared with a minimum effort and data can be processed for special visualization by specialized software. The program was thoroughly tested. Errors were not discovered. However, no guarantee can be made for the completeness and correctness of the programme system and the handbook, or for resulting damage. Should bugs be recognized nevertheless, please contact us immediately. For analysis of the malfunction please send your input data and results. This program is sold without any express or implied warranties whatsoever. Any liability of seller is limited to replacement of diskettes, defective in materials or workmanship. The user is advised to test the program thoroughly before relying on it.

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Contents 1 Introduction and handling...................................................................................... 5 1.1 Installation............................................................................................................. 5 1.2 Menu structure....................................................................................................... 5 1.3 Icon bar.................................................................................................................. 5 1.4 What is new? ......................................................................................................... 6 2 File ......................................................................................................................... 7 2.1 Graphic Format ..................................................................................................... 8 2.2 Print project ........................................................................................................... 8 3 Edit......................................................................................................................... 9 3.1 Project Header ....................................................................................................... 9 3.2 Entering corner point data ................................................................................... 10 3.3 Entering slice data ............................................................................................... 11 3.4 Parameter table.................................................................................................... 12 3.5 Parameter of trees................................................................................................ 13 3.6 Protection structures............................................................................................ 13 3.7 Entering control section ...................................................................................... 15 4 Evaluation ............................................................................................................ 16 4.1 General data......................................................................................................... 16 4.2 Track data............................................................................................................ 17 4.3 Envelopes ............................................................................................................ 18 4.4 Block passage...................................................................................................... 19 4.5 Statistics: structures............................................................................................. 20 4.6 Statistics: control section..................................................................................... 20 4.7 Statistics: Trees ................................................................................................... 21 5 Tools .................................................................................................................... 22 5.1 Tools general ....................................................................................................... 22 5.2 Tools general ....................................................................................................... 23 5.3 Calculation options.............................................................................................. 28 6 Window................................................................................................................ 29 7 Help...................................................................................................................... 30 8 Theoretical background ....................................................................................... 31 8.1 Free fall ............................................................................................................... 36 8.2 Sliding ................................................................................................................. 37 8.3 Rolling................................................................................................................. 38 8.4 Toppling .............................................................................................................. 39 8.5 Inclined throw ..................................................................................................... 40 8.6 Impact calculation ............................................................................................... 41 8.7 Literature ............................................................................................................. 42

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9 ROCKFALL – RockTree Forest Module ............................................................ 43 9.1 Theory ................................................................................................................. 45 9.2 Data entering ....................................................................................................... 48 9.3 Evaluation............................................................................................................ 49

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1 Introduction and handling

1.1 Installation For Installation advises and WIBU Configuration purposes please refer to the appendix “Software Installation” and to http://support.codemeter.de/en/index.html.

1.2 Menu structure Start the programme according to WINDOWS conventions. The initial window shows six menu names at the upper edge:

• File • Edit • Evaluation • Tools • Window • Help

When a menu name is clicked, the so-called menu items drop down, enabling all programme functions can be reached. Additionally, a toolbar with icons appears in the upper part of the programme window. The programme is equipped with a multitude of error messages. Not only impermissible, but also particularly entries conflicting with statements made at another location are generally intercepted and displayed with an error message box on the screen. Data entering and the use of the clipboard correspond to WINDOWS conventions. The programme alters the entry of commas into points automatically. This makes it possible to perform all entering of numbers using the number block on the keyboard

1.3 Icon bar A bar with icons appears in the programme window under the menu names. Essential programme functions can be reached by clicking these icons. The meaning appears whenever the mouse is held over the icon.

New

Open

Save

Print current display

Edit slice data

Show/update profile

Start calculation

Zoom

Zoom +30%

Zoom -30%

Zoom factor

Help

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1.4 What is new? Enhancements and alterations in version 7 compared to version 6.1

• Altered form of graphical display. o View of the profile is opened automatically. o Faster access to the save function.

• Toolbar • Zoom Functions • Envelopes in addition to maximum values, 3 additional curves with details of the fractals. Can

be configured by the user (default values: 95%, 90%, 50%) • Adaptation of the diagram axes (profile, statistics, envelope curves) • Print preview • Print jobs can be configured by the user • Results can be saved if required as track data or as picture for each stone (this does not affect

the saving of the statistical data) • Export as ASCII file (track data, basic data of the statistics for building structures and control

sections). • Better adaptation of the graphical evaluations to the requirements of the individual user.

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2 File Under file, files can be selected, saved and all data relating to the project can be administered.

- New opens a new ROCKFALL Project. You must first enter a name, under which the project is to be saved. The file name is in accordance with the usual WINDOWS conventions. An extension does not need to be given. The extension (*.prf) is automatically added by the programme. If an existing file is selected, the programme reacts with a question. If you insist on this file name, all the data of this file will be overwritten by your new project. This makes it possible to enter and edit details related to the project like project number, date, author, etc.

- Open opens the file of an existing project. The existing project data with the extension *.prf appears in the usual WINDOWS dialog box. Select the desired file.

- Save Saves the data of the current project under its file name. - Save under ... Saves the data of the current project in a new file. The file name and the project-related data can be entered under the button New. The data remains in the old file, as you saved it last time. - Export All printer outputs can be outputted in various graphic formats. The current view is exported in each case. It is also possible for pure text formats to output into the clipboard or as a text file (*.txt).. For the export of calculation results to text files, see also:

• Evaluation/track data • Statistics: structures and cross-sections

- Print preview Shows the currently active view in the form in which it would appear in the printout.

- Print Prints the currently active view. If, for example, the layout window is the uppermost (active) window on the desktop, then the layout plan is printed with the currently valid settings. This applies to the following windows: worksheet, layout plan, section and 3D view. If none of these windows is active, then the menu item print is deactivated and the symbol executes the menu item project. - Print project You can select the views to be printed for the chosen variants and print them out as a sort of batch print. - Printer settings Here you can select the printer and undertake settings in the properties menu of the chosen printer. - End Ends the programme. If one of the menu items new, open or end is called up during the current sitting and the data or calculation results of the current project are not completely saved, then a safety query appears.

• Yes saves the data of the project, and then proceeds with the called up menu item. • No starts the called-up menu item immediately. The latest alterations to the data of the project

are lost. • Cancel breaks off the menu item, which has just been called and returns to the project.

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2.1 Graphic Format Presently supported Graphic formats

2.1.1 Import

Windows bitmap (*.bmp) Windows MetaFile (*.wmf) enhanced MetaFile (*.emf) JPG File Interchange Format (*.jpg) GIF Graphics Interchange Format (*.gif)

2.1.2 Export

Windows bitmap (*.bmp)AutoCad DXF (*.dxf)

2.2 Print project A sequence of print jobs can be sent to the connected printer. Automatic numbering of pages and appendices is possible. On opening, the window lists all print jobs. Evaluations and displays, which are not possible for the relevant project at the current state of processing, appear in grey characters. The desired print jobs are ticked to print them out one after the other in the displayed sequence. The placing of frame and header, and the page and appendix numbering can be set and configured by the user. The Settings button leads to a corresponding form. You can alter the layout and content of existing print jobs here Edit. A form is opened for this purpose, which allows the selected print job to be edited in a preview display. Ok starts the printing. Cancel not only closes the form without starting the printing, but also deletes all entries made here. A click on the cross at top left to close the form has the same effect as the cancel button.

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3 Edit • Project header Entering of details specific to the project, like project number, data, author, etc.

• Enter corner point data Programme function for entering the coordinates of the profile corner points.

• Enter slice data You can enter the parameters singly, and the corresponding parameter variations in percent of the entered value for each slice, or you select a general slice type from the default parameter table.

• Parameter table Programme function to generate a general parameter table. Based on this parameter table, individual slices can be assigned to surface types under the menu item enter slice data

• Enter forest

• Enter protection structure Programme function to enter the coordinates for protection structures.

• Enter control section Programme function to enter the position of cross-sections.

3.1 Project Header The project data identify and name the current project and are shown at the head of all printer jobs.

The default setting provides the seven data rows shown in the illustration. It is also possible to select ones own row labels. The row labels are also saved to each project individually. It is also possible to enter different row labels for single projects. You can replace the logo and the contents of the four rows at top left with details of your firm. A double click on the logo opens a dialog box, in which you can select your own logo (graphic formats), which is

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then automatically included aligned to the left. According to the size and page relationship of the logo, space remains for four rows of text. The size and length of the text rows on the screen may slightly vary from the later print. A test printing is to be recommended. The chosen company logo and the details in the four rows at the left are saved centrally and appear from now with each start of the programme on the screen and on printing of the project header. The characters in the text fields can be chosen or set in font and size by the user. To do this, right click the relevant text field to open the usual WINDOWS menu for configuring text. The four company rows can be configured individually. All other text fields (the seven data rows with their row labels) have the same text style and can only be chosen together, it does not matter which text field is clicked. The placing of frame and header, and also page and appendix numbering can be set and configured by you. The button settings opens the relevant form.

3.2 Entering corner point data The profile of the slope is approximated by a polygon traverse. The individual polygon points are at the same time the borders between the slices, into which the profile is divided. Within the slices, the surface is assumed to be linear.

The coordinates are to be entered according to X/Y values in metres. The slope gradient and thus the direction of motion have to be aligned from left to right. All coordinates must accordingly be entered in this order. Note: If the coordinates from the survey are defined the wrong way round, that is, with increasing values running up the slope, you can for example add a minus sign to the figures. Then the stationing is mirrored and runs with increasing values down the slope, as the programme requires. The function mirroring of the coordinate values is to be implemented soon.

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The coordinates often are already saved on disc from the geodetic survey. Therefore the programme has an import function for ASCII files under import profile data.

3.3 Entering slice data Each data row corresponds to one slice. The individual slices are labelled in the entry form with number and minimum and maximum X coordinates. The parameters and the corresponding parameter variations in percent of the entered value (under V %) are to be given for each slice.

Two types of slices to be entered and to be altered can be differentiated:

• The data can be manually entered here for the individual slices for value or • a general slice type can be chosen for each individual slice. The parameters are then

transferred from the default parameter table

In the display of the entry form, the upper two data rows have a white background, while the lower two data rows have a grey background. The white data rows are manually entered by the user, value by value. The grey data rows are assigned a data type from the parameter table (see chapter Parameter table for detailed information). To do this, the number of the material type from the parameter table is entered in No. (third row). On entering, the description of the type appears automatically and the corresponding row receives a grey background. With changes to the parameter table, the grey rows are automatically updated. As soon as you edit individual values in the grey rows, the link to the parameter table is deleted and the row appears with white background again. Because it can be assumed in this case that you want to make a particular change to the values of the edited slice, which should not to be altered again with an alteration of the general parameters in the parameter table. In the row heads, there is only room for the abbreviation of the relevant parameter. As soon as the mouse pointer is moved onto the row, the corresponding parameter is shown written out in red at the head of the entry form. Additionally, upper and lower limits are stated. For numerical and physical reasons, the programme only accepts entries within this range of values. Invalid entries are shown by a corresponding message.

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If necessary, a suitable value range is also shown (in the third red row). This is a range of values, which from practical experience with rockfall simulation, should not or should as a very rare exception be exceeded.

3.4 Parameter table Programme function to generate a general parameter table. These are the same parameters, which are entered under entering slice data and additionally the name of the slice type. The name of the slice type, marked as surface type in the entry form, is limited to 50 characters. Surface types can be assigned to individual slices with the entry of slice data, based on the parameter table.

If you later alter a parameter value, which is already assigned to one or more slices, the alterations can be transferred automatically to the slice data and thus be used for calculations. However the programme asks whether the slice data should be applied. With yes, they are applied.. With no, the slice data are left unaltered. But the link between slice data and parameter table is deleted for all slices, which were assigned a material type, which was altered here by editing the parameter table.

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To assign a parameter table to a project, click on the button load. You can then open a file (*.sur) with an existing parameter table. Note the following: on altering this parameter table or this file, the altered data become valid also for existing projects, to which this parameter table has been assigned, as soon as you open these again. This does not happen if you save the altered data in a new file with the button save With a new project, which you have not yet assigned a parameter table, you can write parameter values into the still empty entry form. Using the button save you can save the data of this parameter table into a new file (*.sur) A standard parameter table Para_D.sur/Para_E.sur is included with the programme and can be found in the Installation – folder, C:\Programme\Rockfall7 e.g.

3.5 Parameter of trees If your copy of Rockfall includes the Addon Rocktree you do have a Menu Button for the Parameter of the trees. For Information about theses Parameters and how to enter them please refer to Chapter 9: ROCKFALL – RockTree Forest Module

3.6 Protection structures Programme function for entering the data for protection structures.

• x - Abscissa of the foot point in metres, • h - Height of the structure in m, • Incli - Inclination in degrees.

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The X position of the foot point of the structure and the height h of the structure in m are to be entered. The programme calculates the Y coordinate of the foot point of the structure from the level. The structure always stands up on the ground surface. Further, the inclination of the structure in degrees can be fixed (Incli =: 0 means vertical, Incli =: 5 would mean an inclination of the structure of 5° down the slope). An angle greater than 90° is not accepted as an entry. Structures inclined backwards to the slope are also not possible. Up to 10 structures can be considered.

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3.7 Entering control section At the control section, the data of all blocks passing the section are registered and saved for later statistical evaluation. With the entering of a new profile, control sections are automatically defined. These can be edited and configured using the menu item explained here. The x position of the cross-section is to be entered in m. Up to 10 cross-sections can be considered.

The data recorded at the control section are needed for the following evaluations:

• Envelope: energy • Energy: jump height • Block passage • Statistics: control section

The envelopes and the block passage are displays over the length of the profile. If you want to use these displays, the sections should be distributed in sufficient number and evenly over the profile.

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4 Evaluation This section describes the possibilities for evaluating the calculation results. For the presentation of the starting data and results as printout, please consult the help system. With the exception of the menu item, general data the following functions are only active when the motion process has already been started and there are calculation results.

• General data • Track data • Envelope: energy • Envelope: jump height • Block passage • Statistics: structures • Statistics: Statistics: control section • Statistics: forest

4.1 General data Check output of general entered data, options and some calculation results.

• Run label • Starting conditions • Calculation options • Block size and shape • Calculation options • Calculation results like minimum mass, maximum mass and minimum structure height

necessary

The data can be exported in a text file, written on the clipboard or printed.

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4.2 Track data Opens a window to view the track data of any run. Choose the stone according to its number from the menu. The list of track data then appears in the menu window automatically. This menu item is only active when you save the settings chosen as single track data under the menu item tools/calculations/save and display track data.

There are various possibilities available for outputting the track data:

• Clipboard: The data of the currently displayed stone are copied onto the clipboard (in the illustration of the form above, this would be for example the data for stone 7).

• Export: The data of the currently displayed stone are exported in an ASCII file (*.txt). Before the export proceeds, the file name is required, under which the data is to be saved.

• Export of all track data: The data of all stones are exported into one ASCII file (*.txt) each. A file is automatically created for each stone. These are saved in the folder with the file ("ProjectName".prf) of the project currently being processed under the name: "ProjectName"run"StoneNo".txt.

• Print: The data of the currently displayed stone are printed. The windows printer can be selected from the form printer properties, which appears before the print process.

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4.3 Envelopes Shows the curve of the kinetic energy or the jump height over ground level. When the calculation is considering more than one stone, the corresponding envelopes are shown and up to three fractals to be configured by the user. The evaluation proceeds internally in the programme at the relevant control section.

• 100%envelope over the values for all stones • 95% Fractal:: this value is not exceeded by 95 % of all values. • 90% Fractal:: this value is not exceeded by 90 % of all values. • 50% Fractal:: this value is not exceeded by 50 % of all values.

For the various display possibilities, please see tools/layout/envelopes in the Rockfall Help System. You can undertake the arrangement of the axes in the window with the graphic yourself by right clicking on the relevant axis. A form appears for entering axis scale, grid lines, main and subsidiary intervals and label formats. These settings only apply to the current diagram.

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4.4 Block passage The diagram shows selectively over the profile length the number of blocks passing a particular point in the profile

or the number of blocks, which stay put in a particular area of the profile.

The evaluation is through the control section. In the first case, the number of stones at point X is displayed, which are passing the control section with the station=X. In the second case, it is the number of stones, which remain between the control cross-section with the station=X and the previous control section. For the various display possibilities, please see tools/layout/block passage..

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You can undertake the arrangement of the axes in the window with the graphic yourself by right clicking on the relevant axis. A form appears for entering axis scale, grid lines, main and subsidiary intervals and label formats. These settings only apply to the current diagram.

4.5 Statistics: structures Shows the statistical distribution of the following calculation results on one protection structure:

• Overall kinetic energy • Jump height • Kinetic energy translation, • Track velocity, • Bahngeschwindigkeit • Angular velocity • Momentum • Angular momentum, • Angle between rockfall track and protection structure.

The statistics consider only the actual hits on the structure. Read a further explanation of dealing with statistical evaluation in the help System.

4.6 Statistics: control section Shows the statistical distribution of the following calculation results at a control section:

• Overall kinetic energy, • Jump height, • Kinetic energy translation, • Kinetic energy rotation, • Track velocity • Angular velocity • Momentum • Track turning momentum, • Time

The functions for outputting the statistical evaluations are only active when many stones have already been set in motion. On calling the menu items Statistics: control section or Statistics: structures, a form appears in which a histogram can be configured. Then the histogram is displayed in its own window on the screen. The display consists of two parts: the histogram and a text block next to it at the right hand side.

• Max: the maximum value, which has occurred at the evaluated section or structure. • Min: the minimum value • Median: the arithmetical median of all values, which have occurred at the evaluated section or

structure. • STDV: the standard deviation. • 95% Fractal: this value is not exceeded by 95 % of all values. • 90% Fractal: this value is not exceeded by 90 % of all values. • 50% Fractal: this value is not exceeded by 50 % of all values.

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The choice of details in the text block, the choice of colour and style of the histogram and the labelling of the individual bars in the histogram is done under tools/layout/statistics. These settings apply to all statistical evaluations and all further projects. You can undertake the arrangement of the axes in the window of the histogram yourself. To do this, right click on the appropriate axis. A form appears in which details of axis scale, grid lines, main and subsidiary intervals and label formats can be configured. These settings only apply to the current diagram As with the evaluation of the envelopes and the display of the profile, the current view of the statistical evaluation can be printed under the menu item file/print or exported in various formats under file/export. This last option has a special feature. If you select the file extension *.txt, then not the graphic but the calculation results for the chosen structure or the chosen control section are written into an ASCII data set. You then receive the original lists, which the statistical evaluation was based on and can construct your own evaluation on this basis.

4.7 Statistics: Trees This part can be found in the chapter “Forest Module” in the second half of this manual.

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5 Tools There are further menus gathered here to create views, for configuring output options and to configure the calculation options.

• System language: choose between German and English (further languages are in preparation).

• Printout: Configuration of the printer output • Layout: opens programme functions to configure the graphic output. • Calculations: • Default settings: returns all user-defined settings to the default values, with which the

programme was delivered.

5.1 Tools general The following menu can be reached from the menu item tools/general and from the menu data entry/project data by pressing the button settings. Frame The printer output can be with or without frame. Position header The header, that is the text field, can be placed in the four corners of the printout. Following sides The header can be omitted on the following sides. Then only the frame with the page number in the bottom right corner will be shown. Appendix Appendix.X, page The appendices or single outputs are produced with sequential appendix numbering. It is possible to choose with which number the numbering is to start. If a task consists of many sides, then these will be given numbering starting with page 1, i.e. each side receives a new appendix/number. The next appendix would, if it is also of many pages, again start with page 1. Appendix.X.X The numbering of the appendices is automatic and analogous to the previous options. If there are many-sided appendices, there will be a two-place appendix numbering instead of the page numbering. Pages This option does without appendix numbers and works with a sequential page numbering. The number of the first side can be set. Page borders The space from paper edge to the drawing frame can be set here. Vertical or horizontal Printout in vertical or horizontal format; the following special feature is possible. The option Graphic horizontal; reports vertical prints the first graphic with the grading curve in horizontal format and the following details, which consist essentially of text-based tables and reports, in vertical format. This option is the default setting. All the settings mentioned apply for printer and also for monitor.

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5.2 Tools general

5.2.1 Profile

• Ground surface : colour, width and line style for the ground surface. • Ground profile : Filling of the area under the slope profile. • Show slice border If this option is activated, the slice borders are shown in the output as

vertical lines. The slice borders can be configured for colour, width and line style. • Structures : colour, width and line style of the structures. • Sections : colour, width and line style of the control section. It is also possible to set whether

the control section should be shown. • Display of ground surface

o rough o smooth

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5.2.2 Track lines

• Track elevation : The track line display can be raised by the dimension set in mm above the ground profile.

• Track lines : the line colour and width of the track lines can be set here. • Contact point : if a stone comes to rest on the ground or hits a structure, then its position is

marked with the selected symbol, a circle. The size of the symbols denotes the stone diameter.

• Intermediate points : Wherever the stone hits the ground or changes its form of motion will be shown by a circle of the diameter of the stone.

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5.2.3 Envelopes

• Display as o line shows lines going through the profile. o histogram shows bars with the corresponding value at each control section.

• 1. Fractal 100% • 2. Fractal 95% • 3. Fractal 90% • 4. Fractal 50%

The individual fractals can be shown or not shown in the display. The percent value can be given for the second to fourth fractals. The values given above are the default values of the programme. 100% for the first fractal is set unalterably. The colour, width and line style of the line or bar for each fractal can be configured.

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5.2.4 Block passage

• Blocks o Pass through of blocks at each section. o Rest position blocks coming to rest between the section and the previous section.

• Display as o Line shows a full line above the profile. o Histogram shows a bar at each control section with the corresponding value.

• Units o Percent Given in percent of the total number of blocks. o Number The absolute number of blocks passing through or the blocks which come to

rest. • Display style, blocks passing through : the colour, width and line style of the lines or of the

bars can be set here.

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5.2.5 Statistics

• Bars the line colour and width, filling of the bars in the histogram can be configured here. • Labelling of individual bars The value in % can be shown above the individual bars of the

histogram (see illustration). Switch this option on and off here • Details in the statistics block

o Max: dthe maximum value which has occurred at the evaluated section or structure. o Min: the minimum value o Median: the arithmetical median of all values which have occurred at the evaluated

section or structure. o STDV: the standard deviation. o 95% Fractal: this value is not exceeded by 95 % of all values. o 90% Fractal: this value is not exceeded by 90 % of all values. o 50% Fractal: this value is not exceeded by 50 % of all values.

These details at the right hand side of the histogram can be shown or not shown. You can alter the values of the fractals under envelopes.

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5.3 Calculation options

5.3.1 Saving and displaying track lines The track data can either be saved as a bitmap or explicitly as single track data for each stone. In order to avoid an overlarge quantity of data, to be saved to hard disc, we generally recommend the option bitmap. The track data are then only saved as a picture, which is shown with the profile view. All the data necessary for quantitative evaluation are saved to the structures and control sections. In case you need further evaluations and views than those offered by the programme, you can also save data explicitly for each single stone coordinate for coordinate with details of time, velocity, angular velocity and type of motion, and also mass and radius of the stone, by clicking the option single track data. The data are of course, for reasons of disc space and the speed of read and write access, saved as binaries, but they can be exported as an ASCII file at any time or written to the clipboard by using the menu item evaluation/track data.

5.3.2 Recalculation of the profile roughness The roughness is a displacement vertical to the specified profile slope of a slice, which is determined in each case at each point over a random number. With the option recalculation of the roughness, this calculation is repeated in the simulation before the start of each stone. In order to ensure an appropriate statistical evaluation, we recommend the use of this option.

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5.3.3 Calculation control • Limit value VN - lowest permissible velocity normal to ground surface; • Limit value VT - lowest permissible velocity tangential to ground surface.

If both velocities are less than the limiting velocities, then the track calculation is broken off at this point, i.e. the stone comes to rest at this location in the profile and remains there. If only the normal velocity is less than the limiting velocity after an impact, then the stone goes from inclined throw into a rolling motion (compare help systems).

• Separation of support points for the display of track lines. Alteration of this value only affects the saving of data and the display. The precision of the calculation itself is not influenced.

You can increase this value to reduce the quantity of saved data, if you have selected the option single track data. However, the graphical display of the track curves may become a bit angular. Or you reduce the value to achieve a better quality of the outputted track data. If you have selected the option bitmap, the amount of saved data remains unaffected.

6 Window Lists the currently open windows. Click on one of the options mentioned to arrange the open windows according to a default sample.

The uppermost or currently active window is marked with a tick. In order to change to another view (window), click on the relevant window frame.

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7 Help This is how you use the help system. Select the menu item help/help themes, press F1, or click with the mouse on the question mark in the toolbar. After the appearance of the help window, you can choose one of the following tabs:

• tab Contents: You can search the help system organised in categories. • tab Index: An alphabetical subject index is shown. Enter a search word or leaf through the list.

Click in the left hand side of the help window on the selected theme or on an index entry in order to show the relevant theme on the right hand side. All words which are underlined and highlighted in colour lead with a mouse click to a related theme or additional explanation. You can return to your starting point at any time by clicking on back in the help toolbar. The help system is mostly context sensitive. The key F1 automatically calls the help theme with explanations about the form being currently worked on or menu item. You can also reach the help system at any time by pressing F1 from within the form in which the toolbar is not available.

DR. SPANG



8 Theoretical background A two-dimensional profile is determined for the simulation and discretised into single slices. The number and extent of slices is determined according to the form of the slope. The surface properties are assigned to the individual slices and are at first constant over the slices. The simulation calculates the track data of a block according to the laws of motion and impact theory and taking into account the angular momentum. The following types of motion are possible as initial motion of the rockfall.

• freefall • sliding • rolling • toppling

In the course of the motion, the following resulting motions are added according to the slope gradient and geometry.

• sliding • rolling • toppling • inclined throw

After each impact with the ground and at each change of slice, the motion situation is evaluated and the resulting motion initialised with the suitable type of motion in each case.

DR. SPANG



input data- general project information- slope geometry- surface qualities- parameter variation- rockfall barriers- initial conditions

preprocessing- geometry, - surface roughness, - parameter variation

initial movement

free fall rolling sliding toppling

incl. throw rolling sliding toppling

calculation of rockfall paths according to laws of motion

t = t + ti i-1 Δ

t = t

+

ti

i-1Δ

yes

yes

yes

no

no

no

calculation of - kinetic energy- bounce heigth- velocity- momentum etc

evaluation of subsequent movement

output

eventsimpact on surfaceor barrier, change of slope angle

impact on barrier

end of profileor stopping

The calculation is continued until one of the following events (stop criteria) occurs:

• Hit on a structure • Rolling to a stop on flatter ground • Impact with the ground which throws the block back • The block leaves the profile.

The stopping of motion and the decision whether a block continues its motion in inclined throw or rolling after an impact is controlled in the algorithm according to the criterion of falling below the

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limiting velocities. Both limiting velocities, the tangential and the normal limiting velocities, can be chosen by the user according to the problem. When the normal and tangential velocities both fall under the limiting values, the motion is broken off. If the normal velocity falls below the limiting velocity after an impact, the motion is continued as rolling.

For various reasons, the problem of rockfall simulation cannot be solved deterministically:

• Effect of scale of roughness: slope surfaces are macroscopically rough. Rolling or sliding occur in nature mostly over short sections of slope, inclined throws following one another normally have varying jump distances, even on an even gradient. Blocks contact on different surfaces, edges and corners.

• Parameter variation: The properties of the slope surface vary, even within sections of slopes having principally similar characteristics of soil properties and soil layers.

To model these influences, two different methods are used whose shares the user can decide himself by setting the relevant starting values. The two methods are:

• Introduction of a roughness concept for the surface of the slope • Stochastic determination of the starting values to be used at each changeover, for example for

the restitution coefficient using a random generator

So a complete statistical study (stochastic simulation) can be carried out in a single simulation.

DR. SPANG



On the surface of natural scree slopes, there is a grading according to block size. Accordingly, the largest blocks mostly lie at the base of the slope. As can be shown with ROCKFALL and the roughness concept described above, the blocks, whose size lies below or in the range of the roughness size, remain stationary, because they give up their energy through impacts to the sharp

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points; the relatively large blocks roll over their sharp edges, their loss of energy is correspondingly less and their range therefore correspondingly further. The working term "egg box effect" is used.

DR. SPANG



8.1 Free fall Free fall is a uniformly accelerated motion in the direction of the centre of the earth.

acceleration g fall velocity v = g t [m/s] fall distance s = 0.5 g t² [m] with g = 9,81 m/s ² acceleration due to gravity t time from start of fall

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8.2 Sliding Sliding is an accelerated motion parallel to the ground surface.

acceleration a = g * sin ß - g * Rg * cos ß velocity v = a * t + v0 travel distance s = 0.5 a* t² + v0* t + x0 Angular velocity omega = omega (not affected) with ß slope angle of track g acceleration due to gravity t time from start of motion v0 velocity at time t=0 x0 position at time t=0 Rg tangent of the angle of friction under sliding

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8.3 Rolling Rolling is an accelerated motion parallel to the ground surface .

β

v

ω

acceleration a = g sin ß / (1+c) - g Rw cos ß / (1+c) velocity v = a t + v0 travel distance s = 0.5 a t² + v0 t + x0 angular velocity omega = v / radius with ß slope angle of the track g acceleration due to gravity c factor for calculation of moment of inertia (sphere c=0.4; cylinder c=0.5 t time from start of motion v0 velocity at time t=0 x0 position at time t=0 Rw rolling resistance

DR. SPANG



8.4 Toppling Toppling is a circular motion, with a non-sliding condition at the contact point between an edge of the surface and the toppling body (Figure). The equation of motion is derived from energy conservation.

ω

M

dy

angular velocity omega = (E0 - g yi) 2 / (radius ² (1 + c)) track velocity v = omega radius with E0 = 0.5 (1 + c) v0² kinetic energy at the start of motion r radius [m] M moment at pole g acceleration due to gravity c factor for calculation of moment of inertia (ball c=0.4; cylinder c=0.5) t time from start of motion v0 velocity at time t=0

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8.5 Inclined throw The inclined throw is an accelerated motion on a parallel track. The body does not rotate, or the rotation is not influenced by the motion.

(x ,y )0 0

v0x

v0y

acceleration ax = 0 ay = g velocity vx = vx0 vy = - g * t + vy0 travel distance x = vx0* t + x0 (parallel track) y = -0.5 g t² + vy0* t + y0 with g acceleration due to gravity t time from start of motion vx0 velocity at time t=0 in x-direction vy0 velocity at time t=0 in y-direction x0, y0 position at time t=0

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8.6 Impact calculation A rock hitting the surface is modelled as an elastic plastic impact, with restitution (damping) normal and tangential to the impact plane (Figure). Additionally the angular momentum of the rock is taken into consideration in the impact analysis. The tangential force during impact is either governed by dynamic friction or for a harder impact by static friction. Thus we solve the problem of the impact of a sphere or cylindrical shaped mass on rigid surfaces. Applying momentum conservation normal and tangential to the surface as well as the conservation of angular momentum leads to the translation velocities and the angular velocity after impact. ω1

ω2v1

v2

DR. SPANG



8.7 Literature JOHN, K. W. & SPANG, R. M. (1979): Steinschlag - Ursachen, Mechanismen und Sicherungen. UIC - Tagung Schutz der Verkehrsanlagen gegen Steinschlag, Kandersteg (Schweiz). SPANG, R. M. (1987): Protection against rockfall - stepchild in the design of rock slopes. Proc. 6th Int. Congr. Rock Mech., Montreal, I, 551-557. SPANG, R. M. (1988): Empirical and mathematical approaches to rockfall protection and their practical applications. Proc. 5th Int. Symp. Landslides, Lausanne, II, 1237-1243. SPANG, R. M., KURZ, G. & HALLER, B. (1993): Rechnergestützte Planung von Steinschlagschutzbauwerken an der Geislinger Steige. Geotechnik, Sonderheft 1993, 87-90. SPANG, R. M. (1994): Geologisch-Geotechnische Grundlagen des Steinschlagschutzes. Vortr. 11. Bodensee-Tag. Ing.-geol. Naturgefahren, Risikoanalysen, Schutzkonzepte, 21.10.1994. SPANG, R. M. & SÖNSER, TH. (1995): Optimized Rockfall Protection by "ROCKFALL". Proc. 8th Int. Congr. Rock Mech., Tokyo. SPANG, R. M.(1997) Geologisch-geotechnische Grundlagen des Steinschlagschutzes Bündnerwald 4/97 ANGERER, H., SÖNSER,.TH. & SPANG, R. M. (1998) Steinschlagrisiko und Investitionsentscheidung - Gibt es eine rationale Basis? Felsbau 16 Nr. 3 SPANG, R. M.( 1998) Rockfall Barriers - Design and Practice in Europe Seminar on Planning, Design and Implementation of Debris Flow and Rockfall Hazards Migation Measures, Hong Kong SPANG, R. M.( 1999) Dimensioning anchors for rockfall fences - Fatzer AG Sem. Rockfall Tests and Standardization, Davos 25.-26. Jan. Romanshorn SPANG, R. M.( 2000) Standardisierung von Prüfverfahren für Steinschlagschutzbarrieren - Ziele und aktueller Stand 2. Kolloquium Bauen in Boden und Fels, Technische Akademie Esslingen

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9 ROCKFALL – RockTree Forest Module

ROCKFALL - RockTree

Forest Module - Add-on to ROCKFALL 7 for the Simulation of the Influence of Forest

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The add-on module RockTree to ROCKFALL was developed by Dr. rer. nat. R. M. Spang and Dr.-Ing. B. Romunde. Using this add-on module, the effect of trees or forest can be taken into account in the profile of the rockfall tracks. The forest is characterised by the separation of the trunks, the trunk diameter and the height of the trees. Average values are given, which are varied by the programme within bandwidths chosen by the user. The simulation calculates, as in the basic version without forest module, the track data of a block within the two-dimensional vertical profile section according to the possible forms of motion free fall, rolling, sliding, toppling, impact and inclined throw. Additionally, the impacts between the blocks and the trees distributed over the profile are investigated. On contact between tree and block, energy is given from the block to the tree in a partially plastic impact. Also the block is deviated from its original path. The component of motion across the slope is neglected because of the two-dimensional consideration of the falling and overturning motions. Programme functions:

• Rockfall simulation taking into account the influence of forest. • Physically exact calculation of tree contacts. • Automatic variation of the initial data for the forest. • Calculation of the coordinates, the energy and the momentum from impact on trees. • Statistical determination of the energy loss through the effect of the forest. • Output of the energy and jump height distribution along the profile. • Statistical calculation of the distribution of jump heights, the energy and the momentum for the

contact point on protection structures.

The program was thoroughly tested. Errors were not discovered. However, no guarantee can be made for the completeness and correctness of the programme system and the handbook, or for resulting damage. Should bugs be recognized nevertheless, please contact us immediately. For analysis of the malfunction please send your input data and results. This program is sold without any express or implied warranties whatsoever. Any liability of seller is limited to replacement of diskettes, defective in materials or workmanship. The user is advised to test the program thoroughly before relying on it.

DR. SPANG



9.1 Theory The tree is idealised as a cylindrical, elastic, bar fixed in the ground. The crown of the tree is neglected. On contact between block and tree, an inclined, central and partially plastic impact is calculated. The angle of impact results from the relative position between tree axis and the fall path of the block. A random generator controls the position of the tree in the profile.

The impact is determined by the following two values:

• Coefficient of restitution between tree and stone: This value has the same physical relevance as the normal damping between block and ground. It is defined as the relationship between the relative velocities of the two bodies involved in the collision before and after the impact, where the tree is stationary after the collision. After the impact, the tree has a velocity not equal to nil in relation to the stiff underground, either because it fractures and falls or because it is moved by the impact and put into a vibration about its rest position

• The specific impact bending strength related to the cross-section multiplied with the cross-sectional area of the tree gives the energy necessary to fracture the tree. The impact bending strength is the maximum energy, which can be given up by the block on contact between block and tree.

The block loses kinetic energy through each impact, causing its track to change. If the kinetic energy before the impact was less than that which the tree can take up, then the stone is stopped; the motion starts again according to the terrain, perhaps with nil velocity.

DR. SPANG



vv

vv

vv

vn

vn

vn

Various borderline cases can be established on impact between block and tree:

• The block grazes the tree. There is only light contact. Practically no energy is exchanged between tree and stone. Even if the stone has a considerably higher kinetic energy than the breaking strength of the tree, the tree is not destroyed or felled. The damage to the tree is restricted to torn-off bark.

• The stone hits the tree centrally (direct hit). Two cases are to be differentiated here. o The kinetic energy of the stone is less than the breaking strength of the tree. During

the impact process, the entire kinetic energy of the stone is given to the tree temporarily in the compression phase. In the restitution phase, a part of the deformation energy is again converted into kinetic energy. The energy loss of the stone is determined by two factors. A part of the energy is converted into plastic deformation energy. This share is calculated from the coefficient of restitution as the relationship between the velocities before and after the impact. The other share transfers as kinetic energy to the tree, which moves under the impact, that is it accelerates and is then set in vibration.

o The kinetic energy of the stone is greater than the impact bending strength. The stone breaks through or fells the tree. Its loss of kinetic energy corresponds to the impact bending strength.

Between these extreme cases, the energy loss and the deflection of the stone from the fall line are determined by the angle of impact between tree and stone. According to the angle of impact, the full kinetic energy does not affect the tree at the moment of impact, but only a part of it. In additional to the energy loss from the impact, energy loss also results from the deflection of the stone from the fall line. This velocity component across the fall line is established in the impact calculation, but then only considered as energy loss in further track calculation. In the borderline case of central impact, it is assumed, to be on the safe side, that the stone does not come to a stop behind the tree, but starts to move again, as long as the terrain permits this.

DR. SPANG



d

d

F

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9.2 Data entering The forest or forest section is bordered by the placing of the upper edge X0 and the lower edge X End, that is, the start and finish of the forested area. The forested area is characterised by the following parameters, which have to be entered for each individual section of forest:

680 m

720 m

760 m

0 m 40 m 80 m 120 m 160 m

• X 0 : upper edge of the forest section (entry allowed between beginning and end of the profile) • X End : lower edge of the forest section (entry allowed between beginning and end of the

profile). The individual forest sections may not overlap. • AB : Average tree separation (axis separation) in m. • This designation refers to the tree separation crosswise and also parallel to the profile plane

(permissible entry > 2* rB and < x end - x 0) • rB : average trunk radius in m. Permissible entry > 0 und < ab / 2 • V% : Range of variation of tree radius in %. The default values for the tree radii vary in this

case over the entered range of variation with a uniformly distributed density function. Permissible entries between 0 and 100%. (Additional limitation through value range rB )

• Density : Density of the wet wood in g/cm3. Living wood generally has a density of 1.0 to 1.1 g/cm3.

• Coefficient of restitution : Factor for the damping of blows between tree and stone. Permissible entry between 0 (total damping) and 1 (no damping).

• E fracture : Specific impact bending strength related to the cross-section in KN/m2. Permissible entry greater than 0.

DR. SPANG



Baumart Bruchschlagarbeit [Nm/cm2]Ahorn 6.2 - 6.6 Birke 7.5 - 10.0 Eibe 14.7 Edelkastanie - 5.9 Eiche 5.0 - 7.4 Erle 4.9 - 5.3 Esche 6.7 - -8.8 Fichte 4.0 - 5.0 Föhre 4.0 - 7.0 Hainbuche 8.0 - 12.0 Lärche 5.0 - 7.5 Robinie 11.2 - 13.5 Rotbuche 8.0 - 12.0 Tanne 3.5 - 6.5 Acc. to: Sell 1987

9.3 Evaluation It is advisable to carry out two simulation runs for purposes of evaluation, one with and one without the influence of forest. This can be controlled using the option switch consider trees, without having to edit data. In this way the additional braking effect of the forest on the fall tracks can be evaluated by comparing the average kinetic energies on the protection structures. Under the menu item statistics forest influence, two histograms can be created for each forest section to be considered. This menu item is only active during calculations with more than one stone. Whether trees are hit and where the trees are hit are determined by a random generator. It is therefore advisable to carry out simulation runs with a sufficient number of stones and thus tree hits in order to achieve a reliable result. The first histogram, impact energy on tree contact, displays the share of braking energy which is created by the deformation in a partially plastic impact and the kinetic energy transferred to the tree. Using the comparison of the breaking energies, it can be established whether and how many trees are loaded over their strength and felled. The second histogram, total energy loss, considers only the energy loss created by deflection sideways from the fall line.

CIVIL ENGINEERING AND GEOTECHNICAL CONSULTANTS LTD. · The program is based on the laws of motion...

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