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August 2017
REPORT ON
Preliminary Geotechnical Assessment Proposed High Rise Development East Lebreton Flats Ottawa, Ontario
REP
OR
T
Report Number: 1782120
Distribution:
1 e-copy - Claridge Homes 1 e-copy - Golder Associates Ltd.
Submitted to:Claridge Homes 210 Gladstone Avenue, Suite 2001 Ottawa, Ontario K2P 0Y6
HIGH RISE DEVELOPMENT - EAST LEBRETON FLATS
August 2017 Report No. 1782120 i
Table of Contents
1.0 INTRODUCTION .............................................................................................................................................................. 1
2.0 DESCRIPTION OF PROJECT AND SITE ........................................................................................................................ 1
3.0 SUBSURFACE CONDITIONS .......................................................................................................................................... 3
3.1 Available Information ........................................................................................................................................... 3
3.2 Summary of Subsurface Conditions .................................................................................................................... 3
4.0 PROPOSED HIGH RISE DEVELOPMENT ...................................................................................................................... 4
4.1 General ................................................................................................................................................................ 4
4.2 Excavations ......................................................................................................................................................... 4
4.2.1 Overburden Excavations and Shoring ........................................................................................................... 4
4.2.2 Bedrock Excavations and Rock Support ........................................................................................................ 6
4.3 Groundwater Management .................................................................................................................................. 7
4.4 Foundations ......................................................................................................................................................... 7
4.5 Foundation Seismic Design ................................................................................................................................. 8
4.6 Frost Protection ................................................................................................................................................... 8
4.7 General Foundation Wall and Floor Slab Construction Guidelines ...................................................................... 8
4.8 Environmental Considerations ............................................................................................................................. 9
4.9 Impacts on Adjacent Developments .................................................................................................................... 9
4.10 Slope Stability – Fleet Street Aqueduct ............................................................................................................... 9
5.0 ADDITIONAL CONSIDERATIONS ................................................................................................................................ 10
FIGURES
Figure 1 – Key Plan
Figure 2 – Borehole Location Plan
Figure 3 – Surficial Geology
Figure 4 – Drift Thickness
Figure 5 – Bedrock Geology
APPENDICES
Record of Borehole Sheets
Previous Investigations by Golder Associates and others
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August 2017 Report No. 1782120 1
1.0 INTRODUCTION This report presents the results of a preliminary geotechnical assessment carried out for a proposed high rise development to be located southeast of the intersection of Booth Street and Fleet Street in Ottawa, Ontario.
The purpose of this geotechnical assessment was to collect and collate the existing available subsurface information and, based on an interpretation of that information, to provide preliminary geotechnical engineering
guidelines on the design of the development, to identify significant geotechnical design challenges for the project, and to confirm that the proposed development is feasible from a geotechnical perspective.
It is understood that this preliminary geotechnical assessment is required as part of the “Official Plan Amendment” and “Zoning Bylaw Amendment” process.
The guidelines provided in this report are intended solely for the preliminary planning of this development. Further investigation(s) will be required before geotechnical input for the detailed design of this development can be provided.
The reader is referred to the “Important Information and Limitations of This Report” which follows the text but forms an integral part of this document.
2.0 DESCRIPTION OF PROJECT AND SITE Consideration is being given to the design and construction of a high rise development to be located southeast of the intersection of Booth Street and Fleet Street in Ottawa, Ontario (see Key Plan, Figure 1).
The following is known about the property and proposed development (at least at a conceptual level):
The property, which is rectangular in shape, is bordered to the north by Fleet Street, to the east by Lett Street, to the south by the Fleet Street pumping station open aqueduct, and to the west by Booth Street. A high embankment was recently constructed as part of the approach to the Booth Street Bridge over the open
aqueduct. It is understood that this approach embankment was constructed using OLRT tunnel muck wrapped in geogrids, and was finished on the east side of Booth Street (facing the proposed development) with a non-structural facing constructed of wire baskets and crushed rock fill.
The site currently contains a sales center at the northwest portion of the site, but is otherwise undeveloped. The southern portion of land, south of the existing east-west access road between Lloyd Street and
Lett Street, is several metres lower than the surrounding ground elevation.
The entire site was previously remediated by the National Capital Commission (NCC), which involved
removing all of the overburden from the site. A thin veneer of stone dust (crushed stone) was then placed over the bedrock surface. Since the time that the site was remediated, some additional fill material has been placed on this site.
An existing 2.1 x 2.1 metre arch sewer extends along, but outside, the north limit of the property. Plans indicate that the sewer has an invert elevation of about 42 metres, with the crown at about elevation
44 metres. Based on previous investigation and assessment, it was determined that the sewer is located entirely within bedrock, and was constructed using tunnelling methods.
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August 2017 Report No. 1782120 2
Just north of the open aqueduct, is the covered aqueduct, which extends in an east-west direction under the abandoned Ottawa Street right-of-way. The covered aqueduct forms an integral part of the City of Ottawa’s
Fleet Street pumping station works. This covered channel was constructed in about 1912 by blasting/excavating an approximately 6 metre deep and 8 metre wide trench in the bedrock. The aqueduct was then covered with a cast-in-place concrete arch which is still in place today. The arch is founded on and
butted against notches/benches that were created in the upper portion of the rock cut, which is relies on for structural support. Since its original construction, a cast-in-place concrete wall has been constructed which completely covers the north face of the rock cut.
Although the design is conceptual in nature, current plans indicate that the development will consist of the following:
A total of five towers will be constructed on the site.
The towers will vary from about 25 to 45-storeys in height.
The four “northern” towers will have up to about 5 below grade levels to accommodate parking.
The “southern” tower will likely only have one below grade level.
A park area is proposed to be constructed by the City with the support of Claridge Homes (the park site is
not owned by Claridge). The park area will be constructed within the southeast portion of the site, over three stone arch bridges which are designated heritage structures that have not been subjected to regular vehicular loading for at least 50 years. From west to east, the bridges are; the Lett Street Bridge (SN017180), the
Grand Trunk Railway Bridge (SN015110), and the Lloyd Street Bridge (SN017190). The Grand Trunk Railway Bridge (SN015110) was constructed in 1886 between the Lett Street Bridge and Lloyd Street Bridge. The structure has an overall width of 73.9 metres and a clear span of 7.8 metres and formerly carried railway
traffic. The Lett Street Bridge (SN017180) is a stone arch bridge constructed in 1873 and is located east of the Grand Trunk Railway Bridge. The structure has an overall width of 7.6 metres and a clear span of 10.0 metres. The Lloyd Street Bridge (SN017190) is a stone arch bridge constructed in 1873 and is located
west of the Grand Trunk Railway Bridge. The structure has an overall width of 7.6 metres and a clear span of 8.2 metres. In 2001, a masonry restoration project was completed on all three bridges. The restoration consisted of the replacement of deteriorated stones and re-pointing of the masonry joints.
Golder Associates, as well as McRostie and Associates (who have since joined Golder Associates), have carried out several previous subsurface investigations within the immediate area of the site. Testhole locations from those
previous studies are provided on Figure 2. Based on the results of those previous investigations, and based on the fact that all of the overburden was removed from the site during a remediation project, the subsurface conditions on this site are expected to consist of limited thicknesses of recently placed fill material overlying
limestone bedrock.
The surficial geologic mapping produced by the Geologic Survey of Canada (GSC) for the study area is
summarized on Figure 3. Consistent with the borehole data, that mapping indicates that the assessment area is underlain by bedrock at very shallow depth.
Figure 4 summarizes the mapped drift thickness, or trend in the depth to bedrock (i.e., thickness of soil cover). The mapping indicates that the bedrock surface should exist at about 0 to 1 metres depth (consistent with the borehole data).
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August 2017 Report No. 1782120 3
The Geologic Survey of Canada bedrock geology mapping (Figure 5) indicates that the study area is underlain by limestone with interbeds of shale of the Lindsay Formation, however Ontario Geological Survey maps and
previous experience indicate that bedrock in the area of the site consists of interbedded limestone and shale of the Verulam formation which is exposed within the rock cuts beneath the three bridges and in the adjacent covered aqueduct.
3.0 SUBSURFACE CONDITIONS
3.1 Available Information For this assessment, information on the subsurface conditions was obtained from the following sources:
Published Geologic Survey of Canada (GSC) mapping.
Reports in Golder Associates’ records.
The approximate locations of the boreholes which were used from the reports in our records are shown on Figure 2.
3.2 Summary of Subsurface Conditions Based on the factual data compiled from the existing reports, the following section provides a summary of the expected/indicated subsurface conditions at this site.
The borehole data obtained from the previous investigation reports relate to the subsurface conditions at the time of those investigations. The shallow subsurface conditions, particularly with regard to fill depths, have changed
since the time that the reports were prepared. The groundwater levels may have also changed significantly due to surrounding construction and development.
For reference, selected Records of Borehole Sheets which were utilized from the previous investigations are provided in Appendix A.
As previously discussed, it is understood that essentially the entire footprint of the site has been the subject of an environmental remediation project, which involved the removal of all the overburden deposits, down to the bedrock surface; a thin veneer of stone dust (crushed stone) was then placed over the bedrock surface. However, it is
noted that fill materials have been recently placed on the site. The thickness and composition of the fill materials are not known at this time.
Some of the previous boreholes were cored into the bedrock. Based on the core recovered, the bedrock consists of grey limestone. The bedrock was of generally good quality with the exception of the upper 1 to 2 metres which is indicated to be locally weathered and fractured. During previous studies carried out within the open and
covered aqueducts at the south end of the property, where the bedrock is exposed in a rock cut, the following observations were made:
The erosion of joints/fractures (via solutioning and/or mechanical processes) has resulting network of open joints extending into the rock mass, in some locations by 2 metres or more beyond the aqueduct walls;
The preferential erosion and solutioning of the limestone beds and the resulting protrusion of shale beds beyond the general plane of the rock face; and,
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August 2017 Report No. 1782120 4
The occasional saw-toothed pattern of the rock face defined by structural features (regular orthogonal jointing) in the rock mass and the resulting in some minor rock block wedge failures and undermined rock
blocks.
The groundwater level was generally located within the upper few metres of the bedrock surface, which is
consistent with recent groundwater monitoring results on the site located immediately east of Lett Street. The normal operating water level within the aqueduct is above the top of the arch/rock interface, approximately 1 metre below the crown of the arch, or at about elevation 52 metres. It should be noted that groundwater levels
are expected to fluctuate seasonally and with changing water levels in the Fleet Street pumping station works. Higher groundwater levels are expected during wet periods of the year, such as spring.
4.0 PROPOSED HIGH RISE DEVELOPMENT
4.1 General This section of the report provides preliminary engineering guidelines on the geotechnical design aspects of the project based on our interpretation of the existing borehole information and project requirements. It should be emphasized that the guidelines provided herein are appropriate for preliminary design and site planning only.
Additional investigation will be required at the detailed design stage to confirm these guidelines.
4.2 Excavations It is understood that the “northern” four high rise structures will have up to 5 basement levels which will likely
extend up to about 14 metres depth. The “southern” structure may have 1 basement level which may extend to about 3 metres depth below the existing roadway, or to about the existing ground surface elevation.
Considering that the excavations will likely need to extend a further 1.0 to 1.5 metres below the lowest basement floor level to accommodate the foundations and elevator pits, it is expected that the excavation will extend to about 15.5 to 16 metres depth for the northern structures and 4 to 4.5 metres below the general site grade for the
southern structure.
The excavations will therefore extend through the fill materials and into the underlying limestone bedrock.
4.2.1 Overburden Excavations and Shoring
No unusual problems are anticipated in excavating the existing fill material using conventional hydraulic excavating equipment, recognizing that some larger material may be encountered within the fill.
In accordance with the Occupational Health and Safety Act (OHSA) of Ontario, the soils above the water table at this site would generally be classified as Type 3 soils. Unsupported side slopes in the overburden above the water table may therefore be sloped at a minimum of 1 horizontal to 1 vertical.
It is expected that the desire will be for excavations to encompass essentially the full limits of the property and therefore vertical (or near vertical) excavation walls will be required. The contractor should be responsible for the
detailed design of the overburden shoring. However the following general guidelines on possible concepts for the shoring are provided, to be used by the designers for:
Assessing the costs of the shoring;
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August 2017 Report No. 1782120 5
Assessing possible impacts of the shoring design and construction on the design of the structure and site works; and,
Evaluating, at the design stage, the potential for impacts of this shoring on the adjacent structures, services, and roadways.
The overburden shoring method(s) chosen to support the excavation sides must take into account the soil
stratigraphy, the groundwater conditions, the potential ground movements associated with the excavation and
construction of the shoring system, and their impact on adjacent structures and utilities. In general, there are three
basic shoring methods that are used in the Ottawa area: steel soldier piles and timber lagging, driven steel sheet
piles and, less commonly used, continuous concrete (secant pile or diaphragm) walls, each with appropriate lateral
support. Soldier piles and lagging is suitable where the objective is to maintain an essentially vertical excavation
wall and the movements above and behind the wall need only be sufficiently limited that relatively flexible features
(such as roadways) will not be adversely affected. Where existing building foundations lie within the zone of
influence of the shoring (which none are expected at this site), the shoring deflections need to be greatly limited
and interlocking steel sheet piling with pre-stressed tie backs are often used. Secant pile or diaphragm walls would
be appropriate where heavily loaded foundations exist beside the shoring, or where groundwater inflow needs to
be controlled.
For all of the above systems, some form of lateral support to the wall is required for excavation depths greater
than about 3 or 4 metres. Lateral restraint could be provided by means of tie-backs consisting of grouted bedrock
anchors. However, the use of rock anchor tie-backs would require the permission of the adjacent property owners
(including the City, who owns the adjacent roadways) since the anchors would be installed beneath their
properties. The presence of utilities beneath the adjacent streets which could interfere with the tie-backs should
also be considered. Alternatively, interior struts can be considered, connected either to the opposite side of the
excavation (if not too distant) or to raker piles and/or footings within the excavation. However internal struts could
interfere with the construction of the foundations and superstructure.
For this site, it is envisioned that steel solder pile and timber lagging shoring would be used along the entire limits
of the excavation, at least where shoring is required. A minimum of 1 metre offset from the outside edge of the
overburden shoring and the underlying bedrock excavations should be considered in design.
The shoring options will require further evaluation at the detailed design stage, particularly for excavations in close
proximity to the Booth Street approach embankment and retaining wall.
Adjacent to the overburden shoring, some unavoidable inward horizontal deformation and vertical settlement of
the adjacent ground will occur as a result of excavation, installation of shoring, deflection of the ground support
system (including bending of the walls, compression of the struts and/or extension of the tie-backs) as well as
deformation of the soil/rock in which the toes of the walls are embedded. The ground movements could affect the
performance of buildings, surface structures or underground utilities adjacent to the excavation.
As a preliminary guideline, typical settlements behind soldier pile and lagging shoring are less than about
0.2 percent of the excavation depth, provided good construction practices are used, voids are not left behind the
lagging, that sufficient offset is provided between the toes of shoring and the rock cut, and also provided that large
foundation loads from existing buildings are not applied behind the shoring. This guideline would suggest that less
HIGH RISE DEVELOPMENT - EAST LEBRETON FLATS
August 2017 Report No. 1782120 6
than about 10 millimetres of ground settlement would occur for overburden shoring installed to about 3 to 5 metres
depth. However this is only a preliminary guideline and is provided only to assist the owner’s designers in carrying
out an initial assessment of the expected settlements and the potential impacts of these settlements.
4.2.2 Bedrock Excavations and Rock Support
Excavation into the underlying bedrock will require drill and blast procedures or mechanical removal
(e.g., hoe ramming). It is considered that mechanical removal will be too slow to be efficient for the bulk bedrock
removal; however it might be appropriate for the localized deeper excavations for the footings.
Significant caution should be exercised in carrying out blasting due to the near proximity of the adjacent
Fleet Street Pumping Station open and closed aqueducts (southern portion of the site) and the existing sewer that
extends along the north side of the site. Both of these structures are expected to be somewhat brittle and more
sensitive to damage from blast induced ground vibrations. The blasting should therefore be controlled to limit the
peak particle velocities at all adjacent structures or services such that blast induced damage will be avoided.
This will require blast designs by a specialist in this field. It should be noted that drill and blast techniques were
successfully used for the construction of the adjacent development, which was also constructed in close proximity
to the Fleet Street tunnel and aqueduct.
A pre-blast survey should be carried out of all of the surrounding structures and utilities. Selected existing interior
and exterior cracks in the structures as well as any cracks within the sewer tunnel lining and covered aqueduct
identified during the pre-blast survey should be monitored for lateral or shear movements by means of pins, glass
plate telltales and/or movement telltales.
The contractor should be required to submit a complete and detailed blasting design and monitoring proposal
prepared by a blasting/vibrations specialist prior to commencing blasting. This plan would have to be reviewed
and accepted in relation to the requirements of the blasting specifications.
If practical, blasting should commence at the furthest points from the closest structure or service to assess the
ground vibration attenuation characteristics and to confirm the anticipated ground vibration levels based on the
contractor’s blasting proposal.
The available information indicates that near vertical excavation walls in the bedrock should stand unsupported
for the construction period. The existing borehole data provides only very limited information of the bedding and
jointing in the bedrock and therefore this recommendation should be confirmed at the detailed design stage.
Some shotcreting and/or bolting with wire mesh will most likely be needed for worker safety. Blast induced damage
to the bedrock must be avoided; otherwise (additional) rock reinforcement could be required. It should therefore
be planned to either line drill the bedrock along the perimeter of the excavation at a close spacing in advance of
blasting so that a clean bedrock face is formed, or to carry out perimeter drilling and pre-shearing of the excavation
limits using controlled blasting. Depending on the condition of the upper bedrock, the minimum 1 metre offset
between the outside edge of the overburden and the bedrock excavation may need to be increased, or additional
rock reinforcement added to provide suitable bearing for the soldier piles.
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August 2017 Report No. 1782120 7
4.3 Groundwater Management Groundwater inflow, some of which could be significant, should be expected within the excavations. Based on information obtained from an adjacent site, numerous large pumps will likely be required to remove the groundwater. Given the variable hydraulic conductivity of the bedrock (based on testing carried out on adjacent sites), it is difficult to estimate the volume and rate of groundwater inflow. Therefore, one or more larger scale pumping tests, which will provide more representative values of the bulk hydraulic conductivity of the bedrock, should be carried out at the detailed design stage.
Based on the available data, a PTTW from the Ministry of the Environment of Ontario and Climate Change will be required due to the expected rate of groundwater inflow (i.e., the rate of groundwater inflow is expected to be in excess of 400,000 litres per day).
Once the pumping tests have been completed (at the detailed design stage) and if the predicted water inflows (especially for the design of the permanent groundwater management systems) are considered to be unacceptable, several alternatives could be considered to eliminate or minimize the groundwater inflows. Some alternatives could include:
Have shallower basements – This alternative would include designing the buildings with a fewer number of basement levels.
Water-tight construction – This alternative would require that the portions of the buildings below the groundwater level be constructed as a water-tight undrained “system”. For this alternative:
The basement floors would have to consist of concrete, rather than asphalt, and would have to be designed to be integral with the foundation walls.
The basement floor slabs and foundation walls would have to be designed to resist additional hydro-static pressure.
The structures would have to be designed to resist the buoyant forces.
Groundwater inflow would still be an issue during construction.
Perimeter Grout Curtain – This alternative would involve pressure-injecting grout directly into the bedrock at overlapping intervals around the perimeter of the excavations to form a continuous barrier. If constructed properly, the volume of groundwater inflow into the building’s drainage system could be greatly reduced. This alternative would also significantly reduce groundwater inflow during construction.
4.4 Foundations The subsurface conditions on this site are indicated/expected to consist of up to about 1 to 3 metres of fill materials overlying limestone bedrock.
It is expected that all footings will be placed on or within the limestone bedrock.
Footings on or within competent limestone bedrock can likely be sized using an Ultimate Limit States (ULS) factored bearing resistance of about 2 to 5 Megapascals. For footings bearing on or within bedrock, Serviceability Limit States (SLS) generally do not govern the design since the stresses required to induce 25 millimetres of movement (the typical SLS criteria) typically exceed those at ULS. Accordingly the post construction settlement of structural elements which derive their support from footings bearing on bedrock should be negligible.
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August 2017 Report No. 1782120 8
It should be noted that the quality of the bedrock beneath the southern structure may be different from the remainder of the site due to the erosion of joints/fractures (via solutioning and/or mechanical processes)
along the open and closed aqueducts which has resulted network of open joints extending into the rock mass, in some locations by 2 metres or more beyond the aqueduct walls. This being the case, a lower bearing resistance may be warranted for this area, or bearing elements may need to be extended to competent
bedrock at depth.
4.5 Foundation Seismic Design The seismic design provisions of the 2012 Ontario Building Code depend, in part, on the shear wave velocity of
the upper 30 metres of soil and/or rock below founding level.
A Multi-channel Analysis of Surface Waves (MASW) testing program was carried out adjacent to this site, as part
of the previous investigations just to the east of this site.
Based on a review of the MASW test results, the average shear wave velocity of the upper 30 metres of the
bedrock is 1,961 metres per second. Based on these results, and provided that there will be no more than 3 metres distance between the underside of footings and the surface of the bedrock (which is this case for this development), this site can be assigned a Site Class of A.
4.6 Frost Protection All perimeter and exterior foundation elements or interior foundation elements in unheated areas should be provided with a minimum of 1.5 metres of earth cover for frost protection purposes. Isolated, unheated exterior
footings adjacent to surfaces which are cleared of snow cover during winter months should be provided with a minimum of 1.8 metres of earth cover.
It is expected that these requirements will be satisfied for all of the main structure footings due to the deep founding level required to accommodate the below grade parking, and assuming that the parking garage will be heated.
4.7 General Foundation Wall and Floor Slab Construction Guidelines The following assumes that the basements will be designed for drained construction.
Basement walls may be poured directly against bedrock, shoring, and/or formwork. It is noted that some form of
worker protection will likely be required along the bedrock walls (e.g., rock bolts and mesh, and/or shotcrete), which will need to be taken into consideration when sizing the final excavation and building footprint.
Where the basement walls will be poured directly against the bedrock and shoring, vertical drainage such as Miradrain or Deltadrain must be installed on the face of the excavation to provide the necessary drainage.
Where the basement walls will be constructed using formwork, it will be necessary to backfill a narrow gallery between the shoring face and the outside of the walls. The backfill should consist of 6 millimetre clear stone ‘chip’, placed by a stone slinger or chute.
Both the wall backfill and/or the Miradrain should be connected to a perimeter drain at the base of the excavation which is connected to a sump pump.
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August 2017 Report No. 1782120 9
Conventional damp proofing of the basement walls is appropriate with the above design approach. For concrete walls poured against bedrock or shoring, damp proofing using an interior treatment such as Crystal Lok is
suggested.
It is not known whether a concrete basement floor slab or a paved driving surface will be provided for the lowest
basement level of the structures. In either case, in preparation for construction of basement slabs/floors, any loose, wet, and disturbed material should be removed from beneath the footprint. Provision should be made for at least 300 millimetres of 6 millimetre clear crushed stone to form the base of the floor. An under-floor drainage system
should be provided to avoid uplift hydrostatic pressure on the floor slab and/or groundwater leakage into the basement level. Rigid 100 millimetre diameter perforated pipes should be installed within the base material. The perforated pipes should discharge to an outlet such as a sump from which the water is pumped.
4.8 Environmental Considerations The planned drainage system will result in groundwater flow from the surrounding properties towards this site. Therefore groundwater contamination beneath adjacent properties, if present, could be drawn towards this site.
A Phase I Environmental Site Assessment should therefore be carried out to assess the risk of contaminated groundwater existing within this area. The inflow of contaminated groundwater during construction could result in increased groundwater disposal costs. If the inflow of contaminated groundwater would be anticipated in the longer
term, it would be better to construct a water-tight foundation.
4.9 Impacts on Adjacent Developments The planned temporary and permanent groundwater level lowering would be an issue with regards to surrounding
ground settlements if sensitive and compressible clay soils exist within the expected zone of influence of the groundwater level lowering (both during construction and in the long term due to the foundation drainage system). However the results of this investigation as well as published geologic mapping do not indicate such soils as being
present, at least within immediate vicinity of the site.
Regardless, at the detailed design stage, a separate hydrogeological study will need to be undertaken to evaluate
the groundwater pumping requirements and the potential impacts of the proposed development on the hydrogeological conditions in the vicinity of the site. The hydrogeological study will also be required to support an application for a Permit-To-Take-Water.
As discussed in Section 4.2.1, additional impacts could result from ground settlements due to shoring movements, particularly adjacent to the Booth Street approach embankment along the western edge of the property.
4.10 Slope Stability – Fleet Street Aqueduct It is currently planned to construct a structure between the covered and open aqueduct within the southern portion of the site. The northern open aqueduct slope is about 3 to 5 metres high and is comprised of a relatively short
and shallow vegetated slope (which is inclined at flatter than 3 horizontal to 1 vertical) overlying a limestone block retaining wall (which appears to be founded directly on limestone bedrock.
Based on its current configuration, the slope is considered to have an adequate factor of safety regarding global instability (i.e., greater than 1.5 for static conditions and greater than 1.1 for seismic conditions). Provided that that structure is founded on competent limestone bedrock (which will be the case), it is considered that the structure
will not negatively impact the stability of the adjacent slope.
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August 2017 Report No. 1782120 10
5.0 ADDITIONAL CONSIDERATIONS The factual information and guidelines provided in this report are suitable for planning and preliminary design of this development only. Additional investigation and geotechnical design input will be required at the detailed
design stage.
The additional investigation(s) required for the detailed design of this development should include:
Advancing boreholes to at least 5 metres below the underside of the proposed founding level so that the quality and strength of the bedrock can be determined.
Carrying out a large scale pump test so that groundwater inflow into the excavations can be determined, especially given the proximity of the aqueduct.
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1. ALL LOCATIONS ARE APPROXIMATE
1. PROJECTION: TRANSVERSE MERCATOR DATUM: NAD 83COORDINATE SYSTEM: UTM ZONE 18 VERTICAL DATUM: CGVD28
1:2,000 METRES
0002 B 1PROJECT NO. CONTROL FIGURE
KEY MAP
CLARIDGE HOMES CORPORATION
LEBRETON FLATS EASTOTTAWA, ONTARIO
KEY PLAN
CONSULTANT
REV.
2017-06-09
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ABD
TMS
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YYYY-MM-DD
DESIGNED
PREPARED
REVIEWED
APPROVED
1540561
0 40 8020
REFERENCE(S)
NOTE(S)
TITLE
PROJECT
CLIENT
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SF0870BH 8
SF0870BH 9
SF1005BH 451
SF1005BH 454
SF1005BH 455
SF1033BH 505
SF1033BH 540
SF1033BH 508
SF1033BH 509
SF1033BH 539
05112007005-0201
9212783BH.19-5
SF4866BH 209
8212053BH 82 -9
0711210035BH 08-6
1111210018TP 05-4
1111210018BH 11-1
SF-1033BH 538
366300
366300
366400
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CLARIDGE HOMES CORPORATION
1. LAND INFORMATION ONTARIO (LIO) DATA PRODUCED BY GOLDER ASSOCIATES LTD. UNDERLICENCE FROM ONTARIO MINISTRY OF NATURAL RESOURCES, © QUEENS PRINTER 20142. PROJECTION: TRANSVERSE MERCATOR DATUM: NAD 83COORDINATE SYSTEM: MTM ZONE 9 VERTICAL DATUM: CGVD28
LEBRETON FLATS EASTOTTAWA, ONTARIO
BOREHOLE LOCATION PLAN
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CONSULTANT
PROJECT NO. PHASE REV. FIGURE
YYYY-MM-DD
DESIGNED
PREPARED
REVIEWED
APPROVED
LEGEND
@?APPROXIMATE BOREHOLE LOCATION BY GOLDER ASSOCIATES,PREVIOUS INVESTIGATION
ROADWAY
SITE
BUILDING FOOTPRINT
WATERBODY
0 20 4010
REFERENCE(S)
CLIENT
PROJECT
TITLE
r2
1a
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H S
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WELL
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TON S
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SIRJOHN
AMACDONALD
PKY
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366300
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366500
366500
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900
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S B
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N M
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D F
RO
M:
25
mm
0
1:1,000 METRES
CLARIDGE HOMES CORPORATION
1. BÉLANGER, J. R. 2008 URBAN GEOLOGY OF THE NATIONAL CAPITAL AREA, GEOLOGICALSURVEY OF CANADA, OPEN FILE 5311, 1 DVD.2. LAND INFORMATION ONTARIO (LIO) DATA PRODUCED BY GOLDER ASSOCIATES LTD. UNDERLICENCE FROM ONTARIO MINISTRY OF NATURAL RESOURCES, © QUEENS PRINTER 20143. PROJECTION: TRANSVERSE MERCATOR DATUM: NAD 83COORDINATE SYSTEM: MTM ZONE 9 VERTICAL DATUM: CGVD28
LEBRETON FLATS EASTOTTAWA, ONTARIO
SURFICIAL GEOLOGY
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CONSULTANT
PROJECT NO. PHASE REV. FIGURE
YYYY-MM-DD
DESIGNED
PREPARED
REVIEWED
APPROVED
LEGEND
ROADWAY
SITE
BUILDING FOOTPRINT
GSC SURFICIAL GEOLOGY1a. TILL, PLAIN WITH LOCAL RELIEF <5 m
r2. BEDROCK: LIMESTONE, DOLOMITE, SANDSTONE & LOCAL SHALE
0 20 4010
REFERENCE(S)
CLIENT
PROJECT
TITLE
ALB
ER
TS
T
BO
OT
HS
T
PE
RK
INS
ST
EM
PR
ES
S AV
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SLATER ST
FLEET ST
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BR
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D S
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SIRJO
HNA
MACDONALDPKY
LLOY
D S
T
WE
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GTO
N S
T
LET
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ST
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366200
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366300
366400
366400
366500
366500
366600
366600
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700
5030
700
5030
800
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800
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900
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xd
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D F
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25
mm
0
1:1,500 METRES
CLARIDGE HOMES CORPORATION
1. 2010 BÉLANGER, J. R., URBAN GEOLOGY OF THE NATIONAL CAPITAL AREA, GEOLOGICALSURVEY OF CANADA, OPEN FILE D3256, 20012. LAND INFORMATION ONTARIO (LIO) DATA PRODUCED BY GOLDER ASSOCIATES LTD. UNDERLICENCE FROM ONTARIO MINISTRY OF NATURAL RESOURCES, © QUEENS PRINTER 20143. PROJECTION: TRANSVERSE MERCATOR DATUM: NAD 83COORDINATE SYSTEM: MTM ZONE 9 VERTICAL DATUM: CGVD28
LEBRETON FLATS EASTOTTAWA, ONTARIO
DRIFT THICKNESS
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CONSULTANT
PROJECT NO. PHASE REV. FIGURE
YYYY-MM-DD
DESIGNED
PREPARED
REVIEWED
APPROVED
LEGEND
ROADWAY
SITE
BUILDING FOOTPRINT
WATERBODY
TREND IN DEPTH TO BEDROCK (METRES)0 to 1
1 to 2
2 to 3
3 to 5
5 to 10
10 to 15
15 to 25
25 to 50
50 to 100
100 to 200
0 30 6015
REFERENCE(S)
CLIENT
PROJECT
TITLE
11
BO
OT
H S
T
SIRJO
HNA MACDONALD
PKY
WELL
ING
TON S
T
FLEET ST
LLOY
D S
T
LET
T
ST
366300
366300
366400
366400
366500
366500
5030
800
5030
800
5030
900
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900
5031
000
5031
000
Pa
th:
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CLARIDGE HOMES CORPORATION
1. ARMSTRONG, D.K. AND DODGE, J.E.P. 2007. PALEOZOIC GEOLOGY OF SOUTHERN ONTARIO;ONTARIO GEOLOGICAL SURVEY, MISCELLANEOUS RELEASE--DATA 2192. LAND INFORMATION ONTARIO (LIO) DATA PRODUCED BY GOLDER ASSOCIATES LTD. UNDERLICENCE FROM ONTARIO MINISTRY OF NATURAL RESOURCES, © QUEENS PRINTER 20143. PROJECTION: TRANSVERSE MERCATOR DATUM: NAD 83COORDINATE SYSTEM: MTM ZONE 9 VERTICAL DATUM: CGVD28
LEBRETON FLATS EASTOTTAWA, ONTARIO
BEDROCK GEOLOGY
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PROJECT NO. PHASE REV. FIGURE
YYYY-MM-DD
DESIGNED
PREPARED
REVIEWED
APPROVED
LEGEND
ROADWAY
SITE
BUILDING FOOTPRINT
WATERBODY
OGS BEDROCK GEOLOGY11: LINDSAY FORMATION - LIMESTONE; NODULAR TO BLACK LAMINATED
0 20 4010
REFERENCE(S)
CLIENT
PROJECT
TITLE
METHOD OF SOIL CLASSIFICATION
The Golder Associates Ltd. Soil Classification System is based on the Unified Soil Classification System (USCS)
Organic or Inorganic
Soil Group
Type of Soil Gradation
or Plasticity 𝑪𝑪𝑪𝑪 =
𝑫𝑫𝟔𝟔𝟔𝟔
𝑫𝑫𝟏𝟏𝟔𝟔 𝑪𝑪𝑪𝑪 =
(𝑫𝑫𝟑𝟑𝟔𝟔)𝟐𝟐
𝑫𝑫𝟏𝟏𝟔𝟔𝒙𝒙𝑫𝑫𝟔𝟔𝟔𝟔
Organic Content
USCS Group Symbol
Group Name
INO
RG
AN
IC
(Org
an
ic C
onte
nt
≤30
% b
y m
ass
)
CO
AR
SE
-GR
AIN
ED
SO
ILS
(˃
50
% b
y m
ass
is la
rge
r th
an
0.0
75
mm
)
GR
AV
EL
S
(>5
0%
by
ma
ss o
f co
ars
e f
ract
ion
is
larg
er
tha
n 4
.75
mm
)
Gravels with
≤12% fines
(by mass)
Poorly Graded
<4 ≤1 or ≥3
≤30%
GP GRAVEL
Well Graded ≥4 1 to 3 GW GRAVEL
Gravels with
>12% fines
(by mass)
Below A Line
n/a GM SILTY
GRAVEL
Above A Line
n/a GC CLAYEY GRAVEL
SA
ND
S
(≥5
0%
by
ma
ss o
f co
ars
e f
ract
ion
is
sma
ller
than
4.7
5 m
m) Sands
with ≤12% fines
(by mass)
Poorly Graded
<6 ≤1 or ≥3 SP SAND
Well Graded ≥6 1 to 3 SW SAND
Sands with
>12% fines
(by mass)
Below A Line
n/a SM SILTY SAND
Above A Line
n/a SC CLAYEY
SAND
Organic or Inorganic
Soil Group
Type of Soil Laboratory
Tests
Field Indicators Organic Content
USCS Group Symbol
Primary Name Dilatancy
Dry Strength
Shine Test
Thread Diameter
Toughness (of 3 mm thread)
INO
RG
AN
IC
(Org
an
ic C
onte
nt
≤30
% b
y m
ass
)
FIN
E-G
RA
INE
D S
OIL
S
(≥5
0%
by
ma
ss is
sm
alle
r th
an 0
.07
5 m
m)
SIL
TS
(N
on
-Pla
stic
or
PI
and
LL
plo
t b
elo
w A
-Lin
e
on
Pla
stic
ity
Ch
art
b
elo
w)
Liquid Limit
<50
Rapid None None >6 mm N/A (can’t roll 3 mm thread)
<5% ML SILT
Slow None to
Low Dull
3mm to 6 mm
None to low <5% ML CLAYEY SILT
Slow to very slow
Low to medium
Dull to slight
3mm to 6 mm
Low 5% to 30%
OL ORGANIC
SILT
Liquid Limit ≥50
Slow to very slow
Low to medium
Slight 3mm to 6 mm
Low to medium
<5% MH CLAYEY SILT
None Medium to high
Dull to slight
1 mm to 3 mm
Medium to high
5% to 30%
OH ORGANIC
SILT
CL
AY
S
(P
I a
nd
LL
plo
t a
bo
ve A
-Lin
e o
n
Pla
stic
ity C
ha
rt
be
low
)
Liquid Limit <30
None Low to
medium Slight
to shiny ~ 3 mm
Low to medium 0%
to 30%
(see
Note 2)
CL SILTY CLAY
Liquid Limit 30 to 50
None Medium to high
Slight to shiny
1 mm to 3 mm
Medium
CI SILTY CLAY
Liquid Limit ≥50
None High Shiny <1 mm High CH CLAY
HIG
HL
Y
OR
GA
NIC
S
OIL
S
(Org
an
ic
Co
nte
nt
>3
0%
b
y m
ass
)
Peat and mineral soil mixtures
30%
to 75%
PT
SILTY PEAT, SANDY PEAT
Predominantly peat, may contain some
mineral soil, fibrous or amorphous peat
75%
to 100%
PEAT
Note 1 – Fine grained materials with PI and LL that plot in this area are named (ML) SILT with slight plasticity. Fine-grained materials which are non-plastic (i.e. a PL cannot be measured) are named SILT. Note 2 – For soils with <5% organic content, include the descriptor “trace organics” for soils with between 5% and 30% organic content include the prefix “organic” before the Primary name.
Dual Symbol — A dual symbol is two symbols separated by a hyphen, for example, GP-GM, SW-SC and CL-ML. For non-cohesive soils, the dual symbols must be used when the soil has between 5% and 12% fines (i.e. to identify transitional material between “clean” and “dirty” sand or gravel. For cohesive soils, the dual symbol must be used when the liquid limit and plasticity index values plot in the CL-ML area of the plasticity chart (see Plasticity Chart at left). Borderline Symbol — A borderline symbol is two symbols separated by a slash, for example, CL/CI, GM/SM, CL/ML. A borderline symbol should be used to indicate that the soil has been identified as having properties that are on the transition between similar materials. In addition, a borderline symbol may be used to indicate a range of similar soil types within a stratum.
February 2017 1
ABBREVIATIONS AND TERMS USED ON RECORDS OF BOREHOLES AND TEST PITS
PARTICLE SIZES OF CONSTITUENTS
Soil Constituent
Particle Size
Description Millimetres
Inches (US Std. Sieve Size)
BOULDERS Not
Applicable >300 >12
COBBLES Not
Applicable 75 to 300 3 to 12
GRAVEL Coarse
Fine 19 to 75
4.75 to 19 0.75 to 3
(4) to 0.75
SAND Coarse Medium
Fine
2.00 to 4.75 0.425 to 2.00
0.075 to 0.425
(10) to (4) (40) to (10) (200) to (40)
SILT/CLAY Classified by
plasticity <0.075 < (200)
SAMPLES
AS Auger sample
BS Block sample
CS Chunk sample
DO or DP Seamless open ended, driven or pushed tube sampler – note size
DS Denison type sample
FS Foil sample
GS Grab Sample
RC Rock core
SC Soil core
SS Split spoon sampler – note size
ST Slotted tube
TO Thin-walled, open – note size
TP Thin-walled, piston – note size
WS Wash sample
MODIFIERS FOR SECONDARY AND MINOR CONSTITUENTS
Percentage by Mass
Modifier
>35 Use 'and' to combine major constituents (i.e., SAND and GRAVEL, SAND and CLAY)
> 12 to 35 Primary soil name prefixed with "gravelly, sandy, SILTY, CLAYEY" as applicable
> 5 to 12 some
≤ 5 trace
SOIL TESTS
w water content
PL , wp plastic limit
LL , wL liquid limit
C consolidation (oedometer) test
CHEM chemical analysis (refer to text)
CID consolidated isotropically drained triaxial test1
CIU consolidated isotropically undrained triaxial test with porewater pressure measurement1
DR relative density (specific gravity, Gs)
DS direct shear test
GS specific gravity
M sieve analysis for particle size
MH combined sieve and hydrometer (H) analysis
MPC Modified Proctor compaction test
SPC Standard Proctor compaction test
OC organic content test
SO4 concentration of water-soluble sulphates
UC unconfined compression test
UU unconsolidated undrained triaxial test
V (FV) field vane (LV-laboratory vane test)
γ unit weight
1. Tests which are anisotropically consolidated prior to shear are shown as CAD, CAU.
PENETRATION RESISTANCE Standard Penetration Resistance (SPT), N: The number of blows by a 63.5 kg (140 lb) hammer dropped 760 mm (30 in.) required to drive a 50 mm (2 in.) split-spoon sampler for a distance of 300 mm (12 in.). Cone Penetration Test (CPT) An electronic cone penetrometer with a 60° conical tip and a project end area of 10 cm2 pushed through ground at a penetration rate of 2 cm/s. Measurements of tip resistance (qt), porewater pressure (u) and sleeve frictions are recorded electronically at 25 mm penetration intervals. Dynamic Cone Penetration Resistance (DCPT); Nd: The number of blows by a 63.5 kg (140 lb) hammer dropped 760 mm (30 in.) to drive uncased a 50 mm (2 in.) diameter, 60° cone attached to "A" size drill rods for a distance of 300 mm (12 in.). PH: Sampler advanced by hydraulic pressure PM: Sampler advanced by manual pressure WH: Sampler advanced by static weight of hammer WR: Sampler advanced by weight of sampler and rod
NON-COHESIVE (COHESIONLESS) SOILS COHESIVE SOILS
Compactness2 Consistency
Term SPT ‘N’ (blows/0.3m)1 Very Loose 0 - 4
Loose 4 to 10 Compact 10 to 30 Dense 30 to 50
Very Dense >50 1. SPT ‘N’ in accordance with ASTM D1586, uncorrected for overburden pressure
effects. 2. Definition of compactness descriptions based on SPT ‘N’ ranges from Terzaghi
and Peck (1967) and correspond to typical average N60 values.
Term Undrained Shear
Strength (kPa) SPT ‘N’1,2
(blows/0.3m) Very Soft <12 0 to 2
Soft 12 to 25 2 to 4 Firm 25 to 50 4 to 8 Stiff 50 to 100 8 to 15
Very Stiff 100 to 200 15 to 30 Hard >200 >30
1. SPT ‘N’ in accordance with ASTM D1586, uncorrected for overburden pressure effects; approximate only.
2. SPT ‘N’ values should be considered ONLY an approximate guide to consistency; for sensitive clays (e.g., Champlain Sea clays), the N-value approximation for consistency terms does NOT apply. Rely on direct measurement of undrained shear strength or other manual observations.
Field Moisture Condition Water Content Term Description
Dry Soil flows freely through fingers.
Moist Soils are darker than in the dry condition and may feel cool.
Wet As moist, but with free water forming on hands when handled.
Term Description
w < PL Material is estimated to be drier than the Plastic Limit.
w ~ PL Material is estimated to be close to the Plastic Limit.
w > PL Material is estimated to be wetter than the Plastic Limit.
February 2017 2
LIST OF SYMBOLS
Unless otherwise stated, the symbols employed in the report are as follows:
I. GENERAL (a) Index Properties (continued) w water content π 3.1416 wl or LL liquid limit ln x natural logarithm of x wp or PL plastic limit log10 x or log x, logarithm of x to base 10 lp or PI plasticity index = (wl – wp) g acceleration due to gravity ws shrinkage limit t time IL liquidity index = (w – wp) / Ip IC consistency index = (wl – w) / Ip emax void ratio in loosest state emin void ratio in densest state ID density index = (emax – e) / (emax - emin) II. STRESS AND STRAIN (formerly relative density) γ shear strain (b) Hydraulic Properties ∆ change in, e.g. in stress: ∆ σ h hydraulic head or potential ε linear strain q rate of flow εv volumetric strain v velocity of flow η coefficient of viscosity i hydraulic gradient υ Poisson’s ratio k hydraulic conductivity σ total stress (coefficient of permeability) σ′ effective stress (σ′ = σ - u) j seepage force per unit volume σ′vo initial effective overburden stress σ1, σ2, σ3 principal stress (major, intermediate,
minor)
(c) Consolidation (one-dimensional) Cc compression index σoct mean stress or octahedral stress (normally consolidated range) = (σ1 + σ2 + σ3)/3 Cr recompression index τ shear stress (over-consolidated range) u porewater pressure Cs swelling index E modulus of deformation Cα secondary compression index G shear modulus of deformation mv coefficient of volume change K bulk modulus of compressibility cv coefficient of consolidation (vertical
direction) ch coefficient of consolidation (horizontal
direction) Tv time factor (vertical direction) III. SOIL PROPERTIES U degree of consolidation σ′p pre-consolidation stress (a) Index Properties OCR over-consolidation ratio = σ′p / σ′vo ρ(γ) bulk density (bulk unit weight)* ρd(γd) dry density (dry unit weight) (d) Shear Strength ρw(γw) density (unit weight) of water τp, τr peak and residual shear strength ρs(γs) density (unit weight) of solid particles φ′ effective angle of internal friction γ′ unit weight of submerged soil δ angle of interface friction (γ′ = γ - γw) µ coefficient of friction = tan δ DR relative density (specific gravity) of solid c′ effective cohesion particles (DR = ρs / ρw) (formerly Gs) cu, su undrained shear strength (φ = 0 analysis) e void ratio p mean total stress (σ1 + σ3)/2 n porosity p′ mean effective stress (σ′1 + σ′3)/2 S degree of saturation q (σ1 - σ3)/2 or (σ′1 - σ′3)/2 qu compressive strength (σ1 - σ3) St sensitivity * Density symbol is ρ. Unit weight symbol is γ
where γ = ρg (i.e. mass density multiplied by acceleration due to gravity)
Notes: 1 2
τ = c′ + σ′ tan φ′ shear strength = (compressive strength)/2
February 2017 3
LITHOLOGICAL AND GEOTECHNICAL ROCK DESCRIPTION TERMINOLOGY
WEATHERINGS STATE
Fresh: no visible sign of rock material weathering.
Faintly weathered: weathering limited to the surface of major discontinuities.
Slightly weathered: penetrative weathering developed on open discontinuity surfaces but only slight weathering of rock material.
Moderately weathered: weathering extends throughout the rock mass but the rock material is not friable.
Highly weathered: weathering extends throughout rock mass and the rock material is partly friable.
Completely weathered: rock is wholly decomposed and in a friable condition but the rock and structure are preserved.
BEDDING THICKNESS
Description Bedding Plane Spacing
Very thickly bedded Greater than 2 m
Thickly bedded 0.6 m to 2 m
Medium bedded 0.2 m to 0.6 m
Thinly bedded 60 mm to 0.2 m
Very thinly bedded 20 mm to 60 mm
Laminated 6 mm to 20 mm
Thinly laminated Less than 6 mm
JOINT OR FOLIATION SPACING
Description Spacing
Very wide Greater than 3 m
Wide 1 m to 3 m
Moderately close 0.3 m to 1 m
Close 50 mm to 300 mm
Very close Less than 50 mm
GRAIN SIZE
Term Size*
Very Coarse Grained Greater than 60 mm
Coarse Grained 2 mm to 60 mm
Medium Grained 60 microns to 2 mm
Fine Grained 2 microns to 60 microns
Very Fine Grained Less than 2 microns
Note: * Grains greater than 60 microns diameter are visible to the
naked eye.
CORE CONDITION
Total Core Recovery (TCR) The percentage of solid drill core recovered regardless of quality or length, measured relative to the length of the total core run.
Solid Core Recovery (SCR) The percentage of solid drill core, regardless of length, recovered at full diameter, measured relative to the length of the total core run.
Rock Quality Designation (RQD) The percentage of solid drill core, greater than 100 mm length, as measured along the centerline axis of the core, relative to the length of the total core run. RQD varies from 0% for completely broken core to 100% for core in solid segments.
DISCONTINUITY DATA
Fracture Index A count of the number of naturally occuring discontinuities (physical separations) in the rock core. Mechanically induced breaks caused by drilling are not included.
Dip with Respect to Core Axis The angle of the discontinuity relative to the axis (length) of the core. In a vertical borehole a discontinuity with a 90o angle is horizontal.
Description and Notes An abbreviation description of the discontinuities, whether
naturally occurring separations such as fractures, bedding planes
and foliation planes and mechanically separated bedding or
foliation surfaces. Additional information concerning the nature
of fracture surfaces and infillings are also noted.
Abbreviations JN Joint PL Planar
FLT Fault CU Curved
SH Shear UN Undulating
VN Vein IR Irregular
FR Fracture K Slickensided
SY Stylolite PO Polished
BD Bedding SM Smooth
FO Foliation SR Slightly Rough
CO Contact RO Rough
AXJ Axial Joint VR Very Rough
KV Karstic Void
MB Mechanical Break
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