b206-2 - rock grading - opss.prov 206 · rock excavation in roadway cuts, including detours,...

DETAIL ESTIMATING ROCK GRADING

January 2014 of 27 B206-2

B206-2 - ROCK GRADING - OPSS.PROV 206

206-2.1 GENERAL

This section deals with the excavation, haulage, placement, compaction, and

management of rock material, as defined by OPSS.PROV 206.

This section should be read in conjunction with Section B206-1 - Earth Grading, as

the computation methods, balancing of quantities and documentation apply to both.

Rock excavation in roadway cuts, including detours, utilizes a method called “wall-

control blasting”, which is a precise method of rock blasting that minimizes the

overbreak of rock produced by standard blasting techniques, leaving a rock face /

rock surface, as specified. The savings realized in the reduction of rock quantities

offset the additional costs of precision blasting, while safety conditions are improved

by the elimination of irregular walls of jagged rock.

Wall-control blasting is administered under the item Rock Face, which applies in rock

cuts.

Earth material overlying rock formations is termed earth overburden and treated as

earth.

Weathered rock may be classified as earth. Geotechnical staff on the project should

be providing recommendations on when weathered rock is to be classified as earth

and this is usually identified in the Geotechnical Report/Pavement Design

Report/Foundation Investigation and Design Report and shown on the Soils Profile.

On projects where there is rock blasting adjacent to existing pavement, which is not

planned for removal or resurfacing, it has been found that, irrespective of the type of

protection employed, damage to the pavement usually resulted. Therefore, where

widening of rock cuts with a height of 1.5 m or more above the roadway surface is

required adjacent to existing pavement as noted above, an allowance for the

resurfacing of that area of the highway exposed to falling rock is required to be

included in pavement items. See Section B313 for details.

206-2.1.1 Classification of Rock Materials

The following materials, when encountered during grading operations, usually are

treated as rock, and are included in the item Rock Excavation, Grading:

A. Solid Rock

Solid rock means natural beds of hard, cemented parts of the earth's crust

(igneous, metamorphic or sedimentary in origin), which may or may not be



weathered; the weathered material may be highly or only moderately weathered,

but the key is that it has not been moved from its natural bed; as identified in the

Geotechnical Report/Pavement Design Report/Foundation Investigation and

Design Report and shown on the Soils Profile.

B. Boulders and Fragmented Rock

Boulders and fragmented rock measuring 1.0 m³ or larger.

C. Shatter

Shatter is the fracturing of solid rock within the road section by the use of

explosives, to form a suitable foundation to receive the granular base course, and

to provide drainage of the roadbed.

206-2.2 REFERENCES

Commercial Access Manual

Design Criteria - project specific

Drainage Management Manual

Environmental Assessment Report (various names) - project specific

Foundation Investigation and Design Report - project specific

Geometric Design Standards for Ontario Highways

Geotechnical Report - project specific

Highway Design Bulletin 2010-001, Providing Digital Information to Contract,

Special Provision SP 199F61

Hydrology Report - project specific

Pavement Design Report - project specific

Preliminary Design Report - project specific

Recommended Practice For Establishing Rock Elevation For New Highway

Construction, MERO-030

Soils Profile - project specific

Survey Information - project specific

206-2.3 TENDER ITEMS

Rock Excavation, Grading

Rock Face

Rock Supply

Rock Embankment



206-2.3.1 Other Tender Items with Rock Excavation

Rock excavation for the following is not carried out under the item Rock Excavation,

Grading, but under separate items and governing OPS Specifications:

Culverts

Sewers, Manholes, Catchbasins, Ditch Inlets

Subdrains

Structures

These items are detailed elsewhere in this Chapter.

206-2.4 SPECIFICATIONS

Details of the work are contained in:

OPSS.PROV 206 Grading

OPSS 209 Embankments Over Swamps and Compressible Soils

OPSS 316 Extruded Expanded Polystyrene Frost Heave Treatment

OPSS 351 Concrete Sidewalk

206-2.5 SPECIAL PROVISIONS

Refer to Chapter “E” of this Manual to review the applicable special provisions.

As of the publication date of this CDED section, special provisions are required:

1. When shale is excavated with the item Rock Excavation, Grading. The bulking

factor for shale and other factors are required to be stated for shale.

2. Amendment to OPSS 206 for Material For Rock Embankment. Always with

OPSS.PROV 206, November 2013.

206-2.6 STANDARD DRAWINGS

Applicable standard drawings are contained in the OPSD 200 series.

To establish the physical limits on which to base quantities, a familiarity with

applicable standard drawings is required.



It may be required to develop typical sections or modify existing standard drawings

for specific situations, such as, but not limited to:

Sideroad Intersections

Commercial Entrances

Private Entrances

Design of Open Channels

In addition, review of the following manuals should be done, where appropriate:

Commercial Access Manual

Drainage Management Manual

Geometric Design Standards for Ontario Highways

206-2.7 DESIGN

A. Rock Excavation, Grading

This item includes material from the following operations:

Rock Cut and Shatter (integral with roadway section)

- roadway

- side ditches

- transition points

- sidewalks

- widening

- entrances

- frost heaves

- excavation below subgrade

Ditching

- interceptor

- intake/offtake

Boulders and Fragmented Rock, 1.0 m³ or larger

Watercourse Correction

Frost Heaves, isolated

Sidewalks, isolated

Entrances

B. Rock Face

This item applies to those excavations that are part of the final roadway, whether

highway, side road, entrance, detour, etc.



C. Rock Supply

This item is used to provide rock materials if there is insufficient rock materials

for the rock embankments and/or to compensate the contractor if the contractual

rock surplus quantity is not realized.

The item Rock Supply is always used when the contract has either the item Rock

Excavation, Grading or the item Rock Embankment item.

The item Rock Supply is required even when there is a rock surplus on the

project.

D. Rock Embankment

This item is for the construction of rock embankments.

206-2.7.1 Source of Information

A. Design Criteria

The Design Criteria represents a statement of the application of ministry policy

and design standards for a project. The Design Criteria is a concise form for

describing the geometric elements and standards that form the basis for the design

of a new facility or improvements to an existing facility and the extent of the

work to be completed on any project.

B. Survey Information

Survey information is obtained using various methods and technologies

depending upon the needs and requirements of each project.

Available Survey Information will aid in the design and may include field notes,

data, cross-sections, horizontal and vertical alignments, and plans.

Field notes are produced by survey crews and provide details of existing surface

features on the main roadway, sideroads and entrances, and data.

C. Soils Profile

The Soils Profile, when available, shows the existing ground line, proposed

vertical alignment, existing drainage data, and relevant soils data.



D. Reports

A number of reports contain data needed to establish cross-sections upon which

cut and embankment (fill) quantities will be based. These reports are:

Environmental Assessment Report (various names)

Foundation Investigation and Design Report

Geotechnical Report

Hydrology Report

Pavement Design Report

Preliminary Design Report

E. Field Review

A comprehensive field review at the start of the design phase, with plans to record

observations and notes, is invaluable to understand the work and design required.

A field review to verify the design should be carried out near the end of the design

process.

206-2.7.2 Establishing the Rock Surface

Establishing the rock surface is essential to accurate earth and rock quantity

estimates. The survey information, soils information and borehole data is used to

establish the rock surface. The final interpretation should be reviewed with the

geotechnical staff on the project.

Information that can assist in establishing the rock surface is in The Recommended

Practice For Establishing Rock Elevation For New Highway Construction,

MERO-030.

206-2.7.3 Rock Grading Cut Section Options

The Rock Grading OPSDs show two options for the rock cut section from the bottom

of the ditch to the top of cut. Typically, the vertical option is used. However, there are

situations, such as high rock cuts, for uniformity, or to generate additional rock

excavation quantity, where the sloped option is used. A project could have different

options used at different locations.

For high rock cuts, the standard design cross-section may need to be modified to

mitigate for rock falls. For additional information, consult with the Pavements and

Foundation Section, Materials Engineering and Research Office (MERO), the

Pavement and Foundations Section (MERO), and the Geotechnical Section in the

region.



Grading in shale has project specific requirements that are usually in the Geotechnical

Report/Pavement Design Report.

206-2.7.4 Composite Earth and Rock Fills

A composite earth and rock fill embankment has an earth core and a rock shell.

Embankment fills are typically either earth fill or rock fill. Circumstances may

require consideration of a composite earth and rock embankment fill. These

circumstances include:

1. Insufficient quantities of earth or rock fill.

2. Haulage distance.

3. Environmental.

Design guidelines for composite earth and rock fill embankments are available from

the Pavements and Foundations Section, MERO.

206-2.7.5 Rock Materials from Surcharges, Stockpiles and Existing Rock Embankments

Rock material (smaller than 1.0 m³) from surcharges, stockpiles, and existing rock

embankments, that is excavated under the item Earth Excavation, Grading may be

used in embankment construction. The use of the excavated rock material is

determined based on the project needs. When the rock material is to be used in

embankment construction, it is used under the item Rock Embankment.

206-2.7.6 Management of Excavated Materials

Rock excavated from roadway cuts and bulked shatter is used in roadway

embankments.

Rock excavated from other sites such as drains, ditches and channels, when required

and feasible, is used in roadway embankments.

Guide rail may be eliminated by the use of slope flattening.

Slopes behind guide rail may be flattened, even when the guide rail will still be

required.

206-2.7.6.1 Surplus Materials

A rock surplus quantity is an entitlement of the contractor and the responsibility of

the contractor to manage. Contractors may rely on this quantity for production of

granulars and other uses.



Potential uses of surplus rock by the contractor should be considered when optimizing

or balancing quantities for rock excavation and rock embankment.

When there is material quantity that is not used in the design, then the material is

surplus.

To accommodate the surplus material within the project limits, when feasible, there

should be “optional” cross-sections and typical sections or locations or both provided

for use of surplus material. The quantity that can be accommodated at each location is

to be provided. Note that “optional” locations may not have material placed there, and

such are not to be used for locations where construction is mandatory, such as but not

limited to, locations where guide rail has been eliminated from the design with slope

flattening.

Whenever possible, use/disposal locations for surplus materials should be identified

within the project limits. When this is not feasible, then potential locations within the

highway right-of-way and not within the project limits can be used (i.e. slope

flattening, interchange locations, etc.). This would cause the project limits to be

changed.

206-2.7.6.2 Ownership of Designated Disposal Locations

Property designated as a disposal location for excavated material must be owned by

MTO, or MTO must have a legal agreement in place. MTO ownership is preferred.

206-2.7.7 Information to be Provided to Bidders

The following document contains the requirements for the digital and data

information and hard copy information to be provided to all contractors:

Highway Design Bulletin 2010-001, Providing Digital Information to

Contractors, Special Provision SP 199F61

Notes:

1) Soils Data sheets as part of the Contract Drawings.

2) Do not provide a Mass Haul Diagram to bidders.

206-2.8 COMPUTATION

In computing rock quantities, for cut and embankment (fill), subtotal the figures every

350 m along the highway; and on service roads, sideroads, detours, ramps and

entrances, where the length justifies such a breakdown. Each subtotal will constitute a

single-line entry on the Quantity Sheets.



Separation of quantities may be required for left and right sides of a widening project.

Drawings and cross-sections are used to establish the physical limits on which to base

quantities.

The determining the quantity of rock available for use, calculate the volume by taking

the bulked item Rock Excavation, Grading quantity, and adding rock quantities from

boulders, and rock from other items.

206-2.8.1 Stage Construction

When stage construction is proposed, quantities must be determined for each separate

stage, as material excavated in one stage may not necessarily be available for

embankment/fill purposes in a later stage.

In order to obtain accurate rock quantities the quantity calculations and quantity

sheets must be prepared for each stage of the contract.

After the initial determination of quantities for each stage, an analysis to determine a

more cost effective staging strategy and other design changes is to be done when

material is not balancing for each stage. Several iterations may be required to

determine the most cost effective and best design for the project.

206-2.8.2 Bulking Factors

The volume of in situ rock expands when it is excavated, placed, and compacted due

to voids when using broken rock material in roadway embankments or as backfill.

Computed rock quantities need to be adjusted to compensate for expansion by using a

“bulking factor” that is applied to the in situ volume to determine the volume of rock

after expansion.

The bulking factors to be used in the calculations are stated in OPSS.PROV 206.

For projects that have shale, the bulking factor is to be obtained from the Regional

Geotechnical Section and is to be specified in the Contract Documents. This includes

the situation when the factor is 1.0.

When a project has shale and also other rock, the bulking calculations are done

separately, when the bulking factors are different.

The quantity of shatter computed is subject to the same bulking factor as rock cut.

However, the volume of shatter material that is available consists of the expanded

portion only, since the remaining volume of shatter is left in place in the roadbed.

Therefore the factor stated is 0.35 instead of 1.35.



A bulking factor is not applied to the estimated quantity for:

boulders,

rock from surcharges,

rock from existing rock fills, and

rock from stockpiles.

206-2.8.3 Methods of Calculation

Grading quantities are usually determined with electronic computation. However, in

instances of small minor areas, it may be efficient and appropriate to use manual

methods. The use of manual calculations to determine quantities is to be approved by

Ministry management staff in the Planning and Design Section.

Excavation quantities are to be determined using the average end area method, except

for intersections, roundabouts, parking lots, and other similar locations where other

methods achieve better quantity estimates.

Computer applications have many methods of calculating volumes and therefore it is

important to ensure that the desired method is selected.

The current version of the computer application in use with the Ministry for highway

design is to be used for the design and determining grading quantities, when

electronic computation is to be completed.

206-2.8.4 Cross Sections

The interval of cross-sections may vary depending upon the work and roughness of

the terrain, up to the usual maximum interval. Closer intervals should be used for

tight curves.

Usual cross-section minimum intervals between sections are:

25 m, plus break points, for earth, rock embankment (fill), swamp, and borrow

areas

10 m, plus break points, for rock cut areas

20 m, plus break points, for possible rock areas

Cross-sections normally are plotted at a scale of 1:100 both horizontally and

vertically.



The following details should be incorporated in the cross-section from input data:

Original Ground

Rock Surface

Design Section including,

- top of pavement

- top of granular

- subgrade

- grading limits

- ditching limits

- stripping limits

- frost treatments

- transition point treatment

- shatter

- swamp excavation limits

- any other excavation below subgrade

- optional construction sections, when optional areas for disposal of surplus

material are provided (this will require separate quantities to be determined

and documented)

In addition the cross-section will include:

cross-section station number

offset distances and elevation for profile grade elevation

offset distances and elevations for original ground surface

206-2.8.5 Mass Haul Diagram

Mass Haul diagrams are to be prepared for all major grading contracts.

Mass Haul diagrams are to consider the stages of the project, including physical and

environmental restrictions during the stages.

A Mass Haul Diagram serves as a guide in the appraisal of moving materials and

balancing quantities. The comparison of the availability and usage of the excavation

quantities provides guidance as to the feasibility and economy of a grading project.

When analyzing a mass haul diagram for rock excavation and embankment consider

the possible use of rock materials for aggregate production and other similar uses.

After analyzing the diagram, revisions to the set grades or other solutions may be

required. Should a grade revision be required, it is necessary to amend the cross-

sections accordingly, recalculate the pertinent grading quantities and revise the Mass

Haul Diagram.



206-2.8.6 Rock Excavation, Grading

This item is a Plan Quantity Payment item.

The unit of measure is the cubic metre.

The Rock Excavation, Grading item quantity must be determined for each stage of the

work.

206-2.8.6.1 Components of Rock Excavation, Grading

A. Rock Cut for Roadways, Interchanges, Detours, Sideroads and Entrances

Rock cut is material classified as rock as per OPSS.PROV 206, and which is

excavated from the rock surface down to the top of shatter (i.e. bottom of granular

sub-base), as outlined in the theoretical section applicable to a particular project.

Quantities are computed separately for roadways, interchanges, detours, etc., and

subtotalled at 350 m intervals.

Excavated rock is a fully usable material for embankment construction and

backfilling. The total volume computed is considered available for use.

(a) Widening of Existing Roadbed

In order to maintain traffic during stage construction, cut sections may require

widening beyond the limits set in the standards. Where widening to maintain

traffic is necessary, it should be considered as a detour and the appropriate

quantities should be included in the tender.

(b) Excavation for Widening in Cuts to Achieve a Project or Stage Balance

In order to achieve a balance of cut and fill requirements for a grading

contract when grade adjustment is not feasible, widening of cut sections

beyond the limits set in the standards, or excavating within interchange loops,

medians or similar operations are acceptable alternatives.

When widening a rock cut to increase the rock excavation quantity and obtain

rock for use, the entire length of the rock cut is to be widened a uniform

width. The widening of a rock cut may lengthen the rock cut to reach the zero

rock location.

It is much more cost effective to widen deep cuts to achieve balance than to

widen a series of small cuts, and it also enhances rock fall mitigation.



These possibilities should always be investigated and, if no conflict with

design or soils recommendations is apparent, should be implemented, if the

total cost of excavating, including the stripping quantity not usable for fill, the

haul to the required fill area, and utility relocations is more economical than

using the item Rock Supply and property is available.

B. Shatter

In a rock cut section, to provide drainage, the top 0.3 m of rock subgrade is

shattered, since trapped water can cause poor pavement performance. To prevent

such damage the top 0.3 m of rock grade is “shattered” and the resultant rock

fragments left in place to a depth of 0.3 m to provide rock “matting” that will hold

any granular materials placed. The bulked portion is excavated.

Shatter is not required in a shale subgrade.

It may be necessary to shatter deeper than 0.3 m in order to facilitate drainage of

the pavement structure as shown in Fig. B206-2-1. Where this is the case, the total

depth of shatter must be shown on the drawings.

All shatter shown on the drawings, regardless of depth, is computed at full

volume.

Shatter quantities are subtotalled at the same breakdown intervals as those for

rock cut quantities.

C. Frost Treatment

Frost heaving is caused by freezing temperatures acting upon frost-susceptible

soils and free water below the subgrade. The combination of these factors results

in the formation of frost lenses, which, by expanding upward, cause substantial

and costly damage to the pavement structure. Frost heave damage is particularly

severe on roads in the northern part of the Province.

Frost heave treatment is applied in areas specified by the geotechnical staff on the

project and is done according to OPSD standard or as recommended in the

Geotechnical Report/Pavement Design Report/Foundation Investigation and

Design Report.

Frost heaving of the roadbed may result from earth and water trapped in hollows

formed between knobs of rock at shallow depths. Treatment to provide drainage

may include rock shatter below subgrade, as shown in Fig. B206-2-2.

Frost heave areas must be given drainage treatment by means of deepening

ditches, if possible, or by installing subdrains or French drains. It is important to

ensure drainage is provided to an adequate outlet so ponding in the excavated area



does not occur. Where the provision of drainage is very costly, the geotechnical

staff on the project should be consulted for possible alternative treatments not

requiring a drainage outlet. Approval of management staff in the Planning and

Design Section is required when a drainage outlet is recommended to not be

provided.

To prevent future frost heaves, rock excavation to remove rock knobs below the

subgrade may be required, usually to a specified depth, to eliminate potential

pockets of frost susceptible earth between rock knobs and to provide good

drainage.

D. Rock Excavation for Intake/Offtake Ditching and Water Course Correction

(a) Intake/Offtake Ditching

Ditching in rock, other than side ditches in cut sections, usually means

intake/offtake ditching at culvert locations. Interceptor ditches are not required

on rock surfaces, except if they are a continuation of other ditches.

Fig. B206-2-3 illustrates the cross section of a typical intake/offtake ditch in

rock.

The quantity of ditching is calculated from cross sections using depths from a

set ditch profile. The material obtained from rock ditching is available for

embankment construction.

Shatter is not required for intake/offtake and interceptor ditching through

rock.

(b) Watercourse Correction

A watercourse correction is defined as an alteration to a natural watercourse,

up to a culvert or apron face, if flowing through a culvert.

Excavation within the limits of a culvert, and its aprons/end section is part of

the work of other tender items and is paid for accordingly.

The Hydrology Report will have information on the watercourse requirements

for the computation of quantities and the incorporation of the final design into

the contract drawings.

The excavated rock material resulting from watercourse correction although

generally accepted as available for fill, is rarely used to fill in the old

watercourse; it is more commonly used for embankment construction.



E. Boulders and Fragmented Rock, 1.0 m³ or larger

Boulders and fragmented rock measuring 1.0 m³ or larger within earth excavation

is regarded as rock and is not included in the earth quantities.

The geotechnical staff on the project, based on field investigations, may include in

their report findings an evaluation of boulders (those measuring 1.0 m³ or larger)

existing in some cuts. Because of the difficulty in determining their volume, a

percentage factor to be used for calculation purposes may be recommended.

After computing the volume of excavation based on an earth cut section, the

following procedure should be implemented;

Below is an example (fictional) calculation to show the process:

Volume of Earth Cut section 10 000 m³

Less: Volume of Boulders (assuming 10%

recommended by geotechnical staff on the project) 1 000 m³

Earth Cut available quantity 9 000 m³

The rock quantity from boulders will be 1 000 m³. The bulking factor is not

applied to this quantity.



206-2.8.7 Rock Face


The unit of measure is the square metre.

Rock Face is the surface area in square metres of the rock faces in each rock cut area.

The vertical limits of the rock face are top of rock (rock surface) to the designated

rock or ditch grade surface.

Rock Face quantities are computed for each rock face, left and right sides separately,

and are separate entries on the Quantity Sheets.

At sideroads and entrances, the rock face will follow the flare to the end of the

individual rock face.

For rock cuts that are benched, the Rock Face item applies to all vertically oriented

surfaces but not to the horizontally oriented surface.

The Rock Face item is required when previous rock cuts are widened.

The Rock Face item does not apply to slopes in shale.

Areas of Rock Face are not computed for ditching.

Areas of Rock Face are not computed for watercourse correction.

206-2.8.8 Rock Supply

This item is not a Plan Quantity Payment item.


The item quantity for Rock Supply shall be the larger of:

1.15 x (Rock Embankment item quantity - (Rock Excavation, Grading item

quantity x bulking factor)) Note: Not applicable if a negative number, or

10% of Rock Excavation, Grading item quantity, or

15% of Rock Embankment item quantity, or

300 cubic metres, or

1.15 x (total of the rock shortage quantities for each stage added together)

The staging of a project must be considered in the determination of the Rock Supply

quantity.



In order to determine the Rock Supply quantity for the contract, a “rock shortage”

quantity must be determined for each stage of the project. Rock that is not required in

an earlier stage is available for use in a later stage, when determining a “rock

shortage” for a stage. The calculated rock shortage quantities for each stage are not

included in the Quantity Sheets however they are used in the calculation of the Rock

Supply item quantity.

Sample Rock Supply Quantity Calculation (example fictional project)

Rock shortage quantity for each stage = A - B - C.

Where:

A = Rock Embankment item quantity, for the stage.

B = Rock Excavation, Grading item quantity x (times) bulking factor, for the

stage.

C = Rock Excavation, Grading item quantity x (times) bulking factor, for previous

stage(s) - (minus) the required Rock Embankment item quantity for the

previous stage(s). Zero (0) if negative, as no material available from previous

stages(s).

For a stage, when the quantity is a negative number there is no rock shortage for the

stage.

Stage 1 Stage 2 Stage 3 Project

Total

A = Rock Embankment item quantity, for the

stage. 2000 5000 2000 9000

B = Rock Excavation, Grading item quantity x

(times) bulking factor, for the stage. 3000 2000 4000 9000

C = Rock Excavation, Grading item quantity

x (times) bulking factor, for previous

stage(s) - (minus) required Rock

Embankment item quantity for the previous

stage(s).

0 1000 0 N/A

Rock shortage quantity for the stage = A-B-C.

Zero (0) if negative, as no material available

from previous stages(s).

0 2000 0

Rock available for next stage(s). 1000 0

Rock surplus available to contractor. 0 0 2000 2000



Rock Supply quantity is the greater of:

1.15 x (Rock Embankment item quantity - (Rock Excavation, Grading item

quantity x bulking factor)) = 1.15 x (9,000-9,000) = 0

10% of Rock Excavation, Grading item quantity = 0.10 x 9,000 = 900

15% of Rock Embankment item quantity = 0.15 x 9,000 = 1,350

300 cubic metres = 300

1.15 x (total of the rock shortage quantities for each stage added together) = 1.15

x 2,000 = 2,300

Thus, the Rock Supply item quantity is 2,300 cubic metres.

The project looks like a balanced job (A - B = 9000 - 9000 = 0).

But in fact, there will be a rock surplus for the job of 2000 and rock excavated in

stage 3 is not available for construction in stages 1 and 2. There is a rock shortage of

2000 in stage 2.

206-2.8.9 Rock Embankment



The Rock Embankment item quantity is to be determined for each stage of the work.

For additional information, refer to Section B209 for fill design and computation for

embankments in swamp excavation locations.

The work of compaction is included in the item and does not require any

computation.

206-2.8.10 Utilization Excavated Materials

A. Embankments Construction (Rock Embankment)

Rock Embankment is the placing of rock material within the design section from

the bottom surface of the design up to the subgrade elevation.

Rock Embankment uses rock material from cuts, shatter (bulked amount),

ditching watercourse corrections in rock, and other sources and includes boulders,

all of which is placed in the embankment to the cross section of the applicable

rock embankment design. Rock material may be placed in areas of swamp



backfill or any other area recommended by the geotechnical staff on the project,

however, it is designated, calculated and detailed as “Rock Embankment”.

(a) Combination Fills (Rock and Earth) that are not Composite Earth and Rock

Fills

Combination earth and rock fills are rare and not done as a matter of the usual

design practice, but are sometimes done to use the material available. Ministry

geotechnical staff is to be involved in the decision to use combination fills.

Embankments may consist of both earth and rock materials in varying

proportions.

Earth fill should not be placed over rock fill due to the risk of future distortion

due to earth moving into rock voids. Also the materials should be placed full

width i.e., no longitudinal transitions between earth and rock. Transverse

transitions are to be as per OPSD.

When earth is the predominant grading material, the earth fill section standard

is applied even though the location contains some rock material.


volume of fill (based on earth fill section) 10 000 m³

less: available rock fill (includes bulking factor) 2 000 m³

earth fill volume 8 000 m³

earth fill required (assuming a 15% volume adjustment factor) 9 200 m³

When rock is the predominant grading material, the rock fill section standard

is applied even though the location contains some earth excavation. The

method of calculation is as follows:

volume of fill (based on rock fill section) 10 000 m³

less: available rock fill (includes expansion factor) 9 000 m³



In these examples, note that in each case the total quantity of available rock

material (major or minor) is utilized before computing earth fill requirements.

(b) Rock Fill (Boulders)

In earth embankments where boulders from adjacent cuts are used for fill,

quantities are adjusted.




volume of fill 12 000 m³

less: rock fill (boulders)* 1 000 m³



*The rock bulking factor is not applied to boulders placed in fills.

Boulders, cobbles, and fragments of rock and reclaimed materials should not

be used or disposed of in areas where pile driving for future structures is

envisaged. These materials and others can result in piles being “hung up”

within this material and not reaching the designed tip elevations. Contract

documents should demarcate areas where this option is prohibited i.e. those

areas where structures are planned in the future.

B. Swamp Backfill (Rock)

Rock may be used as backfill to swamp excavation. Geotechnical

Report/Pavement Design Report/Foundation Investigation and Design Report will

contain specific excavation, backfill and embankment material recommendations

to be used for each swamp.

Refer to Section B209 Embankments Over Swamps and Compressible Soils for

fill design and computation information.

C. Structure Backfill (Rock)

Concrete structures may be backfilled with rock. When granular material is not

readily available, in order to reduce high granular costs, or to achieve consistency

in the highway embankment construction, rock available for fill may be used as

backfill material. Before opting for rock backfill, a cost comparison must be

completed to determine the selection of the more economical alternative.

The structural staff on the project is to be involved in the decision of determining

the selected structure backfill material.

D. Drainage Gap in Rock Embankments

When surplus or unsuitable material is designated for flattening rock

embankments, gaps in the flattening material must be provided at the low point

for cross drainage and at other strategic locations according to the OPSD

standard.

Neglecting to provide drainage gaps may result in embankment failure due to

hydrostatic pressure or frost action.



The location of the drainage gaps should be indicated on the contract drawings by

station and standard number.

E. Frost Heave Backfill

Roadbeds excavated for frost heave treatment will be backfilled with granular

material in accordance with Ontario Provincial Standard Drawings, as set out in

Section B314 of this Chapter.

F. Optional Locations for Surplus Materials

Refer to the section 206-2.7.5.1 Surplus Materials, for information on the use of

surplus material in “optional” cross-sections, typical sections, and locations.

Quantity calculations are required.

206-2.9 DOCUMENTATION

206-2.9.1 Contract Drawings

Drawings are to show the embankment dimensions, including shape, grades and

limits. This is done with standard OPSDs, plans, profiles, cross-sections and typical

drawings. Profiles show graphically information from the design cross-sections.

Modifications to standard drawings and project typical sections may be required for

the locations where material excavated is to be incorporated into the design, or used,

or disposed of within the right-of-way.

Modifications to standard drawings and project typical sections may be required for

the locations where additional fill material must be placed after expected

displacement or settlement has occurred, to achieve the design profile and cross

section.

Material that is to be incorporated within the right-of-way must have its location

shown on the plans.

To accommodate the surplus material within the project limits there should be

“optional” cross-sections and typical sections or locations or both specified for such

material.

Where OPSDs do not reflect the project requirements typical design cross-sections

are to be included in the contract drawings. Typicals are usually required to reflect the

project requirements.



The elevations of solid rock formations must be plotted on cross sections and contract

profiles.

When extensive side cut occurs throughout a project, a typical section should be

shown on the drawings.

Typical cross sections are required for frost heave treatment areas (where the OPSD

is not typical), and areas where excavation below subgrade is needed, showing the

full extent of treatment necessary, including provision for drainage, where required.

When OPSDs for Transition Treatments are used, values for “t” (transition treatment

depth) and “d” (depth granular base and subbase) and “Do” (depth of organic, leached

and accumulate layers) are included in the drawings. This is shown on the Profile

drawings.

When OPSDs for Frost Heave Treatments are used, values for “d” (depth of granular

base and subbase) and “k” (depth of frost treatment below profile grade) are included

in the drawings. This is shown on the Profile drawings, in a table, or typical sections.

Plans are to clearly show the full extent of drainage improvements to achieve positive

drainage of the subgrade for frost heaves.

When flared guiderail terminations are required, show the location of the widened

embankment. This may mean that interpolated cross-sections have to be inserted at

the termination points.

When a particular type of material is to be used at a specific location, that material

must be identified on the drawings or in a NSSP.

Swamp must be plotted on profile and treatment (by OPSD No., or typical section)

indicated.

For each swamp, the total quantity of embedment, settlement and construction loss

for material below the waterline quantities is to be included in the special provisions

or the contract drawings. Refer to Section B209 for additional information.

Any excavations below subgrade must be shown on the profile sheets.

The location of the drainage gaps should be indicated on the contract drawings by

station and standard number.

When excavated materials have disposal sites, refer to Section B206-1 for required

information.



Soils Data sheets as part of the Contract Drawings and contain, when applicable:

title block (date(s) of investigation, name of firm, type of equipment used, and

disclaimers);

soils borehole logs;

soils and aggregates laboratory testing data; and

other information as required.

206-2.9.1.1 Quantity Sheets (Q-sheets)

Quantity sheets are usually provided in 11X17 format. Information on Quantity sheets

is contained in Chapter F of this manual.

For the items:


Rock Embankment

These items have the quantities documented on the “Quantities - Grading” sheet.

When stage construction is proposed, quantities must be documented for each

separate stage.

The quantities for the following locations are shown separately for 350 m intervals:

Highways

Service Roads

Ramps and Loops (when separate profiles are shown)

Sideroads

Detours

Separation of quantities may also be required for left and right sides where it will

clarify the quantity information. This could apply to widening projects, reconstruction

projects and other work as appropriate.

For the item Rock Face:

The item Rock Face has the quantities documented on the “Quantities -

Miscellaneous” sheet.

Rock Face entries, are shown for, each rock face, left and right sides separately, and

are not subject to the 350 m breakdown.

When there are only a few entries, Rock Face is shown on the “Quantities - Grading”

sheet, within each 350 m breakdown.



For the item Rock Supply:

The item Rock Supply has the quantities documented on the “Quantities - Grading”

sheet.

Rock Supply is shown as a single entry as “Throughout Contract”.

The quantities for Rock Excavation, Grading, Rock Embankment and Rock Face for

the following locations are shown for the total contract:

Entrances

Sidewalk (isolated locations not part of grading section)

The quantities for the following components of Rock Excavation, Grading are shown

separately in individual rows for each location:

Cut

Ditching/Sidewalk

Swamp

Frost Heaves (isolated locations not part of grading section)

Watercourse Corrections

Unusually large entrance quantities

Shatter

Totals for each component location are entered in columns designated for:


Rock Face

Rock Supply

Rock Embankment

Rock From Boulders

Rock From Other Items

Optional Rock Fill

Rock required for structure backfill shall be identified as “Rock Backfill to

Structure”, with a separate entry for each structure under the column for the item

“Rock Embankment”.

The totals of excavation quantities resulting from the work of culverts, structures,

etc., that are to be used for the work under the item Rock Embankment, are

transferred from their respective item quantity sheets to the quantity grading sheets

and shown as materials for use when the quantities are significant. This is shown in

the column for “Rock from Other Items”.

Excavated rock material from rock fills, rock surcharges and rock stockpiles, that are

to be used for work under the item Rock Embankment, are transferred from their



respective item quantity sheets to the quantity grading sheets and shown are shown in

the column for “Rock from Other Items”.

The total computed volume of boulders (Rock) must be shown as a separate entry

under the column for “Rock From Boulders”.

Material that is in the design to be incorporated inside the right-of-way must have its

location and quantity shown on the quantity sheet.

Material that is “optional” for use inside the right-of-way must have its location and

quantity shown on the quantity sheet.

The item columns are totalled and the quantity for each item is transferred to the

Tender documentation.

All other columns on the quantity sheets are totalled and the tender item box is

crossed out as they are non-tender item quantities.

206-2.9.2 Non-Standard Special Provisions (NSSPs)

Write project and item specific requirements in a NSSP using the standard format

described in this manual.

Topics that require a NSSP are:

Rock dumping locations permitted, when it is allowed.

Rock backfill to structures gradation or sizing, when rock to be used as structure

backfill is a different gradation or size than stated in OPSS.PROV 206.07.06.

Areas where larger or interlocking materials, such as but not limited to boulders,

rock, etc., are not to be used in the embankment or fills (i.e. where there are future

structures or other areas where these materials are not to be placed).

The maximum limit of open excavation allowed adjacent to the travelled

roadway, when the normal contract provisions will not suffice. Restrictions may

be needed for stability of the existing roadway.

Excavation and embankment fill restrictions.

Embankment construction requirements that influence the use of designated

disposal areas.

Disposal site requirements.

For each swamp, the total quantity of embedment, settlement and construction

loss for material below the waterline quantities is to be included in the special

provisions or the contract drawings. Refer to Section B209 for additional

information.



When a particular type of material is to be used at a specific location, that

material must be identified on the drawings or in a NSSP.

Staged embankment construction requirements over compressible soil.

When a material is stockpiled for use on a future job the details are to be provided

including how hauling and placement is paid, and rock size restrictions.

Any work by a specialized person to be done regarding rock cuts after they have

been excavated. Discuss the need with the ministry Geotechnical Section.

Detour and staging requirements.

Environmental considerations.

206-1.9.2.2 Operational Constraint for Mandatory Construction Sequence

The sequence of excavation and embankment construction must be such that disposal

areas that are specified will be available when the associated material is excavated.

A NSSP may be required to establish a mandatory construction sequence to ensure

the specified disposal areas are available when the associated material is excavated.

206-2.9.3 Documentation Accuracy

All quantities are rounded to whole numbers.