1/7 1.0 PURPOSE This specification describes the minimum requirements for the backfilling of trenches or the construction of berms primarily for the installation of buried pipelines, cables, ducts and the like. This specification supplements the requirements of the Occupational Health and Safety Act, and its Regulations and the Building code. 2.0 DEFINITIONS "The Six-Inch Layer Compaction Method" means the spreading of backfill material in uniform full width layers not more than 6 inches in depth after compaction. "Backfilling Operation" means the activity required to fill surface depressions or to backfill excavations. "Sound" or "suitable" as applied to fill materials means free from deleterious matter, having a reasonably uniform gradation which permits compaction to a stable mass, and having the characteristics specified for the particular materials, all after handling, rehandling, processing and reprocessing where necessary. "Unstable" or "unsuitable" as applied to fill material means too wet, too dry, frozen or containing ice, snow, organic or other deleterious matter, or having poor characteristics for grading and compaction, or having other characteristics that may result in undesirable settlement or movement of the fill or within the fill, or otherwise not meeting the requirements of the specifications. However, this definition permits drying, dewatering, watering, thawing and any other processing or reprocessing to make the material stable and suitable prior to incorporating it into the fill. "Fill" and "backfill" are deemed to have the same meaning. "Service Line Testing Procedure" means the testing of installed service lines according to requirements of applicable regulatory agencies and the Vale Representative. Over-excavation means excavation beyond the authorized zone or the zone required to build the structure as specified
2/7.0 GENERAL.1 STOCKPILING OF MATERIAL The Slopes of stockpiled materials and bermes where the height is in excess of 4 feet (1.22 meter) must possess their own technical report or plans produced by a qualified professional, including the following items: Physical characteristics of the mound/slope; Total height; Elevations of base and crest; Overall slope angle; Height of earth banks; Width of periodic horizontal strips; Height of slopes between periodic horizontal strips; Slope angles between periodic horizontal strips; Operational lifespan; Area occupied; Degree of risk; Vegetation or synthetic protection measures on earth slopes exposed to the weather; Possible obstructions to the operation of machinery/equipment that may be positioned in areas close to slopes or other earthworks, in terms of the dynamic effects that their operation may have on the mounds; Earth banks used as access routes must meet traffic safety criteria. Stockpile backfill material within designated areas. Stockpile granular material so as to prevent segregation and change in moisture content. Should any material become segregated, remix the material to provide uniform gradation. Remove excess backfill material not required for other purposes and dispose of at a designated location. Rough grade those materials in the disposal areas to promote drainage and to give a tidy appearance to the satisfaction of the Vale Representative. Exercise care at all times to prevent earthfill materials from becoming contaminated by clay and other types of deleterious materials. 4.0 BACKFILL 4.1 BACKFILL MATERIALS Backfill materials and compaction are as specified on the project drawings.
/7 Conform to the requirements of Vale Specification SPEC-11004 entitled "Earthfill Materials". 4.2 GENERAL Do not place backfill on frozen, snow-covered, ice covered or wet ground. Maintain minimum overburden cover as specified on the project drawings. Co-ordinate fill operations with other Work. Do not place fill until subgrade has been compacted to the required density determined by ASTM D698 (Standard Proctor Test) or ASTM D1557 (Modified Proctor Test). Do not cover any subgrade or work until authorized by the Vale Representative but otherwise place in the fill as soon as possible. Prevent damage and disturbance to subgrade, other work and existing buildings and installations. Keep heavy equipment at a safe distance, clear of structures and other installations. Within the safe distance place fill by hand or other suitable means and compact it by means of hand guided power rollers or tampers operated to avoid damage to the structures and installations. Eliminate boulders and rock fragments larger than 6 inches, when earth or fragmented rock fill is permitted within 2 feet of structure, on the top of piping, electric ducts and cable. Fill uniformly on all sides around structures and other installations not designed as retaining walls, and prevent unbalanced loadings. For earth and granular fill, deposit the fill material as near as practical to its final location and spread it in accordance with the Six-Inch Layer Compaction Method. Make each layer the full width of the fill required at its elevation, with the layer horizontal except for a slight slope of approximately 2% to promote surface drainage in the event of rain while the layer is exposed and except as required to suit the required elevations of the completed fill. Where earth fill material contains boulders or rock fragments, place and work the materials so that all such solid pieces are well distributed and all interspaces are completely filled. Eliminate such solid pieces, over 6 inches in their greatest dimension, from fill placed within 1 foot of the surfaces of earth fill. For earth and granular fill, compact each layer to the required density before placing further material on it. Adjust and control the moisture content to within plus or minus 1 percent of
4/7 the optimum, adding water or drying the fill material as and when necessary. Add water and dry the fill material by means of suitable equipment capable of producing uniform results throughout the fill material. For concrete fill other than concrete bedding, place and cure the concrete in accordance with CSA-A2.1. Produce a dense surface but do not trowel or otherwise make the surface smooth. Co-ordinate backfill operation with service line testing procedure. Continue backfilling so that no more than 200 ft. of service line remains exposed at any time except where sections must be left open for a short period of time to facilitate further construction. Backfill over excavated zones by lean concrete having 15 MPa strength unless otherwise approved by Vale representative. 4. SHEETING, BRACING AND SHORING Do not leave sheeting, bracing and shoring in place without the Vale Representative prior approval. Submit a written request for approval, to the Vale Representative. If the Vale Representative gives approval, sheeting, bracing and shoring may be left in place. Where sheeting, bracing or shoring are left in place, cut off and remove to a depth of ft. minimum below finished surface, unless otherwise instructed. If instructed, remove installed sheeting, bracing and shoring by withdrawing it in stages consistent with the progress in placing and compacting fill such that no movement occurs in the sides of the excavation. Completely and promptly fill voids formed during the withdrawal, compact the fill using rammers suitable for working in the confined spaces. Co-ordinate the activities to ensure adequate support is always in place. 4.4 BEDDING Remove all surface organic material, rock and debris prior to laying bedding material over virgin or previously filled areas. Use bedding materials as specified on the project drawings and conform to the requirements of Specification SPEC-1101 - "Bedding Materials".
5/7 Place bedding material in accordance with the Six-Inch Layer Compaction Method. Use Granular "B" Type II bedding material with 100% of material passing the 26.5mm sieve in lieu of Granular "A" bedding material where dewatering of trench becomes impossible, or where minerock or ripped slag fill is used as substrate. 4.5 BACKFILL IN CUTS THROUGH BUILT-UP AREAS Place backfill material over bedding in trenches situated under roads, parking lots, walks, finished landscapes, slabs on grade, railway tracks, or the like, as specified on the project drawings using the Six-Inch Layer Compaction Method. Restore excavations to their original state with respect to all courses and toppings. Ensure finished surfaces are free of bumps and depressions and correctly sloped and cambered. 4.6 BACKFILL IN CUTS THROUGH AREAS OTHER THAN BUILT-UP AREAS Place backfill material over bedding in trenches situated in general areas by pushing or rolling into place avoiding the practice of allowing "free-fall". No compaction is required unless specified otherwise on the project drawings. Overfill trench to produce mound equal in height to 1/4 of the width of trench. 4.7 METHOD OF PLACING EMBANKMENT FILL Build up fill material on each side of previously placed bedding material. Deposit it layer for layer at each side alternatively until the bedding material is covered. Complete construction of embankment over bedding. No compaction of embankment fill material is required unless specified otherwise on the project drawings. 5.0 SUBMITTALS Submit to the Vale Representative when requested: 5.1 SAMPLES A sample not less than 100 pounds, typical of each type of fill material from each proposed source. With each sample, submit results of testing proving the material complies with the gradation and physical requirements specified. The Vale Representative s approval of any sample will not mean approval of the entire source. All materials from any source are subject to further sampling, testing and approval/rejection, whether incorporated into the work or not.
6/7 5.2 Test Reports and Certificates Test reports showing the results of gradation, moisture content, compaction, physical requirements and other test. 6.0 INSPECTION AND TESTING Inspect and test the subgrade and fill materials to determine suitability of materials, moisture content and density of materials in place. 7.0 REFERENCE DOCUMENTATION The following documents are related to this specification and shall be used to their latest revision: SPEC-11004 SPEC-1101 CSA -A2.1 ASTM D698 ASTM D1557 ASTM D698 SPEC-1101 Earthfill Materials Buried Pipelines Bedding Materials Concrete Materials and Methods of Concrete Construction Standard Test methods for laboratory compaction characteristics of soil using standard effort (12,400 Ft-LbF/FT (600 KN-m/m )). (Standard Proctor Test) Standard Test Methods for Laboratory compaction characteristics of soil using modified effort (56,000 Ft-LbF/FT )) (Modified Proctor Test) Standard Test Method for in-place density and water content of soil and soilaggregate by nuclear method (shallow depth). Bedding Materials
7/7 8.0 REVISION AND TRANSITION NOTES Revision notes describe: what was changed, and if applicable, why it was changed, and the plan to implement the change, including whether changes are retroactive. Note: The revision notes are a summary of the changes and may not necessarily be a complete list. Rev 1 Description Document format and number changed due to Vale Engineering Document Program changes in 2011. Previous Standard number was 1106-02.01.611 Rev. Revision by Approved by Issue Date YYYY/MM/DD K.Clausen A.Alaeddine 2012/04/0 2 Approved for use in Thompson, MB - No changes K.Clausen A.Alaeddine 2012/08/09 Document Reviewed Format updated Regional approvals removed - Spelling and duplicate reference documentation corrected. K.Clausen A.Alaeddine