A 6 m high cutting, sloping at an angle of 1.5 horizontal to 1 vertical (1.5H:1V) is planned as part of a new
railway in regional Victoria. Note that the alignment of the railway has been fixed and the toe of the cutting
cannot be moved.
A further consideration in construction of the cutting is that there is a power line 4 m from the crest of the
proposed batter. To allow access for maintenance equipment the power company requires access 2 m
either side of the power line, with equipment that will apply a uniform 20 kPa (20 kN/m3
per metre slope
width) surcharge over this area. The access requirement means that the power line must be at least 2 m
from the crest of the cutting once it is excavated.
A single borehole has been drilled at the location of the cutting as part of a preliminary geotechnical
investigation along the rail alignment. The simplified materials encountered in the borehole are
summarised in Table 1. The groundwater table was encountered at a depth of 6 m below the ground
surface and following excavation it can be assumed to be coincident with the excavated surface.
0 – 2 m Clayey Sand, orange brown, dense
2 – 2.5 m Clay, grey, firm
2.5 – 10 m Clayey Sand, orange brown, dense
Table 1. Simplified log of Borehole 1
Laboratory testing conducted on samples retrieved from the borehole indicated that the drained strength
parameters of the geotechnical materials are as listed in Table 2. Note that the properties of the upper
and lower ‘clayey sand’ layers are the same.
Cohesion, cÆ (kPa) Friction angle, Ä³ Æ (degrees) Unit weight È– (kN/m3
Clay 5 16 18
Clayey Sand 3 36 20
Table 2. Geotechnical parameters of materials
Figures 1 and 2 show two alternative interpretations for the borehole stratigraphy based on either
horizontal layering (Interpretation A) or inclined beds (Interpretation B), with the latter interpretation
suggested by geological mapping. The geometry of the proposed slope and the location of the power line
are also shown on these figures. This assignment is to be undertaken on an individual basis. Each report is to be submitted via the Turnitin
link on LMS before the due date of submission (11:59 pm, Friday 10 October 2014). Late submissions
without notification and justification will not be assessed.
Please take very careful note that where copying and plagiarism is detected, penalties will be severely
applied. Plagiarism has been clearly identified in this subject in previous years and penalties have
The Department has 50 site licences for the full commercial version of programs in GeoStudio, which
includes SLOPE/W. Therefore, although there may be times during which access is limited to complete all
aspects of this assignment, students should be aware that there is a student version of SLOPE/W which
can be easily downloaded from the website (www.geo-slope.com). This version is the same as the full
commercial version but has a number of limitations on the number of features that are available for use.
These limitations include only 3 materials and non-inclusion of line loads and reinforcement loads.
Despite this, this student version is ideal for learning how to use the software in conjunction with the very
useful set of tutorials and examples which can also be downloaded from the same website. Part 1 of the
assignment can be completed using the student version, and a significant part of Part 2 can also be done.
It follows that in the interests of using the facilities we have for the best advantage, all students are
encouraged to use the student version in the learning and initial stages of the modelling exercise, and
then only using the more limited access full commercial version when finalising analyses. Note that you
can use the datafiles for both versions of the software.
Also, because of the limited number of site licences, it is important that during the day, you keep to your
allocated time in the computer laboratories.