for Highway Construction Page 139 of 71 5 SECTION 205 – EXCAVATION AND EMBANKMENT
205.01 Description.
Excavat e, haul, dispose of, place, and compact specified materials necessary to construct the work.
A.Excavation . This work includes excavation performed under this contract pay item regardless of the material encountered. The Department may divide excavation into schedules.
B.Blasting. Use explosives to fragment rock. Perform the blasting operations in accorda nce with the Engineer -approved blasting plan.
C.Embankment . Construct embankments with soil, aggregates, rock, or other materials.
1.Soil Embankment. Embankments with materials that can be tested for in- place dry density in accordance with the WAQTC FOP for AASHTO T 310 Method B.
2.Rock Embankment. Embankments with materials that are too granular to test as specified in Table
205.03 1.
3.Embankment with other materials. Embankments constructed with other materials instead of soil or rock, if specified. These materials include wood fibers, light -weight concrete, recycled glass, and geofoam. Use recycled glass that meets the requirements of 720.05.
D.Shoulder Grading. Blade, process, and finish material on the roadway shoulders to match the typical plan section.
E.Soft Spot Repair. Excavate and repair soft spots as directed. The Engineer will identify soft spot repair locations on the project site. Additional areas beyond plan quantity may be identified.
F.Guardrail Terminal Grading. Construct guardrail terminal grading.
205.02 Materials.
A.Borrow . Obtain borrow from designated or approved sources.
B.Granular Borrow . Provide sand, sand and gravel, or sand and rock mixtures obtained from designated or approved sources. If the material has a sand equivalent less than 30, it must have less than 5 percent passing the No. 200 sieve, in accordance with AASHTO T 27 / T 11. The Contractor may use RAP as granular borrow when approved. Mix RAP in approximatel y equal proportions with material meeting the granular borrow requirements. for Highway Construction Page 140 of 71 5 C. Dust Abatement . Provide water for dust control. When magnesium chloride is required, provide a brine that is between 28 and 35 percent solution with a maximum of 5 percent impurities as determined by AASHTO T -143 and ASTM E - 449.
D.Shoulder Materials. Provide ¾ inch aggregate for untreated base that meets 703.04.
E.Soft Spot Repair. Provide materials for soft spot repair as follows:
1.Provide granular subbase backfill that meets 703.11.
2.Provide ¾ inch aggregate for untreated base, Type A or B, that meets 703.04. The Department will sample the ¾ inch aggregate for untreated base from the stockpile.
3.Provide approved Superpave HMA pavement .
4.Provide CSS -1 tack that meets 702.03.
5.Provide Type III subgrade separation geotextile that meets 718.07.
6.Provide Type II biaxial geogrid that meets 641.
7.Provi de coarse aggregate for concrete that meets 703.02.
F.Acceptance.
1.Granular Subbase, Untreated Aggregate for Base and Coarse Aggregate for Concrete. The Department will perform a single aggregate gradation for each item per source for acceptance. Document this gradation on an ITD-901 form.
2.The Department will accept Type III Subgrade Separation Geotextile and Type II Biaxial Geogrid by certification .
3.The Department will accept, granular subbase, untreated aggregate for base , coarse aggregate for concrete , and HMA including compaction by ITD -850, ITD -854, and/or ITD -855 form(s) as applicable, documented once per soft spot.
G.Other materials. Use materials other than soils or rock in constructing embankments as specified.
H.Guardrail Terminal Materials. Provide ¾ inch aggregate for untreated base, Type A or B, that meet s 703.04.
205.03 Construction Requirements.
A.General. Do not work beyond the dimensions and elevations specified. Stake and cross -section areas to be worked before removing material. Maintain a well -drained roadway. Maintain the subgrade during construction as specified in 105.13 and 105.14. for Highway Construction Page 141 of 71 5 Dispose of surplus or unsuitable excavated material at approved locations. Comply with 107.17. Obtain written per mission to access project sites required by a stormwater pollution prevention plan (SWPPP) until final acceptance. The property owner must acknowledge, in writing, they have been made aware the contract may remain active and access to the project site may be required after the contract is complete. Alternatively, the property owner, by written agreement, may take responsibility for complying with requirements, (e.g., the National Pollutant Discharge Elimination System (NPDES) permit ) by becoming a third party to the notice of intent (NOI). Do not waste material. Schedule excavation and borrow operations to avoid unauthorized waste of excavation. Protect erodible surfaces of cut and embankment slopes as specified in 212. Remove and dispose of material originating outside the staked lines of any cut slope that fails due to causes beyond the Contractor’s control. Remove and dispose of the material and refinish the cut slopes as directed.
B.Slope Finishing. Finish slopes as specified. Remove loosened or shattered rocks that will not remain in their natural position, as determined by the Engineer, from the slopes. Remove and dispose of any safety hazards caused by overbreak from the Contractor’s operation (e.g., rocks shattered or loosened outside the staked lines of cut slopes).
C.Shoulde r Grading. Place shoulder aggregate in sufficient quantities to match the plans. Blade the shoulder aggregate back to the pavement edge to form a smooth slope with the paved roadway edge as specified or as directed. Compact the shoulder to meet Class D requirements or as directed. Do not damage the new overlay. Use appropriate traffic control to accomplish this work. Replace any delineators, mile posts, or signs damaged during this operation with new Department- approved materials at no additional cost to the Department. Shoulder grading is not required in guardrail areas. Broom the pavement to remove aggregate and shoulder material remaining on the overlay surface. Grade shoulder material and vegetation to the paved surface. Remove and waste shoulder material and vegetation in a n approved manner.
D.Process Old Road . Scarify the old road to full depth of the road ballast and spread to form a uniform foundation where the old road surfacing is within 5 feet of the roadbed of the new road.
E.Excavation and Repair of Soft Spot . Excavate the material from the soft spots using equipment that does not aggravate the soft spot condition or disturb the underlying soils. Waste excavated material at an approved, Contractor -furnished waste site. Excavate down 2 feet minimum from the top of the roadbed or to the lines and grades as directed. Line the excavated area bottom with subgrade separation geotextile, followed by biaxial geogrid, or as directed. for Highway Construction Page 142 of 71 5 Stretch out and tem porarily secure the geotextile and geogrid in place with staples, pins, sandbags, or as directed. Keep the geotextile and geogrid taut and without wrinkles during the first backfill lift placement . Dump and spread the backfill in uniform lifts to maintain the required thickness at all times. Place backfill over the geogrid with low ground pressure (< 5 psi) track equipment (e.g., small dozers designed for low ground pressure to avoid ove rstressing or disturbing the soft foundat ion soils). Place the first backfill lift over the geogrid at least 1 foot thick and not more than 2 feet thick (loose). Compact the first backfill lift as directed. Construct subsequent lifts i n accordance with 205. Do not operate track ed construction equipment on the geogrid until it is covered by the first backfill lift. Do not turn tracked equipment on the first backfill lift. Operate rubber -tired equipment on the geogrid at speeds of less than 5 mph and only if the underlying material is capable of supporting the load. Overlap adjacent geotextile and geogrid edges and roll ends at least 2 feet, and lap in the same direction that the backfill will be spread. Cut the geotextile and geogrid, and diagonally overlap around corners so that all locations will have at least a 2 foot overlap and buckling or wrinkling does not occur. Ensure that the geotextile and geogrid sections do not become separated at overlaps during backfill placement . Repair damaged geotextile and geogrid sections by placing a new piece of geotextile or geogrid over the damaged area with a minimum 3- foot overlap on all edges at no additional cost to the Department. Backfill areas that are excavated beyond the directed lines and grades at no additional cost to the Department. Provide positive drainage away from soft spot excavations to the fore slope by trench excavation, or as directed. Construct trenches at least 0.5 foot wide, line with subgrade separation geotextile, and backfill with coarse aggregate for concrete. Construct trenches to drain by gravity to the ditch line. Cap the soft spot repair areas with 0.5 foot (compacted thickness) of untreated aggregate for base. Finish the base top surface to allow the HMA pavement to match the existing pavement thickness. Tack the existing pavement vertical edges before paving. Match the existing pavement thickness. Compact the backfill and the base to Class A requirements . Compact the HMA with 6 roller passes, or as directed.
F.Embankment Construction . Prepare the nat ural ground surface as foundation for embankment by removing vegetation, topsoil , and other unsuitable materials and scarifying to provide a bond with the new embankment. Do not place emba nkment material until the foundation has been approved. Do not construct embankments with frozen materials or on snow covered or frozen foundations. Key new embankments constructed on existing slopes steeper than 3H:1V with horizontal benches having a vertical face approximately 1 foot in height. Slope each bench to drain. Incorporate material excavated from the benches in the embankment or waste the material if directed. Drain seepage encountered from the embankment . Construct the first lift of an embankment across swampy ground or saturated soils by end dumping with an adequate thickness to provide a stable surface. Construct the rest of the embankment in layers as specified. for Highway Construction Page 143 of 71 5 Allow emb ankment material containing excessive moisture to dry to the appropriate moisture content to meet compaction requirements. Provide sufficient water to facilitate compaction and to meet the required density. This water is incidental .
1.Soil Embankments. Place soil embankments in horizontal layers 8 inches thick or less before compaction. Uniformly compact each layer at the required moisture content and to the specified compaction class.
2.Rock Embankments. Rock embankment material must classify as too granular to test per
205.03 G.1 after compaction at its final placement point. Othe rwise, embankment compaction
must meet Class A requirements per 205.03.G.1. Maintain embankment material in a visibly wet condition during compaction . The Engineer will allow the placement of isola ted individual, competent rock fragments having dimensions greater than the specified loose layer thickness if:
a.The clearance between adjacent rocks provides adequate space for placement and compaction equipment to compact the materials in horizontal layers as specified.
b.The rocks are placed more than 36 inches below the roadbed. When a majority of the embankment materials are rocks or rock fragments, distribute the material in a manner that avoids nesting and provides spacing between the rocks to allow for filling and compacting smaller rocks and soil. Compact rock embankments as follows:
a.Compaction within 18 inches of the roadbed and rock backfill of over-excavated areas in rock cuts: Place material in loose layers 9 inches thick or less. Uniformly compact each layer with at least 12 full overlapping coverages of a vibratory roller meeting the minimum requirements specified in this section . The Cont ractor ma y reduce vibratory rolling by 1 full coverage for each 5,000 pound increase per impact above the specified minimum. Ensure at least 6 full overlapping coverages per each 9- inch loose lift or fractional portion.
b.Compaction at a depth greater than 18 inches below the roadbed: Place material in loose layers 18 inches thick or less. Uniformly compact each layer with at least 3 full overlapping coverages for each 6 inches of loose lift thickness or fraction portion with rollers meeting the following minimum requirements:
1.Vibratory rollers having a rated centrifugal force of 30,000 pounds per impact and at least 1,000 vibrations per minute. Limit vibratory roller speed to less than 130 feet per minut e.
2.Grid rollers having a static weight of at least 20,000 pounds and 4000 pounds per foot of drum width. Limit grid roller speed to less than 350 feet per minute. The Contractor may reduce rolling requirements by 1 coverage per each 6 inches of loose lift thickness, or fraction thereof, for each 5,000 pound increase per impact above the specified minimum for vibratory rollers, or 1000 pound increase per foot of drum width above the specified minimum for grid rollers. Ensure at least 1 complete overlapping coverage for each 6 inches of loose lift thickness or fractional portion. for Highway Construction Page 144 of 71 5 If some of the embankment material generated classifies as testable material according to Table
205.03 1 in its final co mpacted place, then place and compact according to soil embankments
in 205.03.F.1.
3.Density Determination. Determine the maximum dry density in accordance with the following applicable test methods: Moisture Density Relations of Soils ........................................................ AASHTO T 99 Method C A block of concrete weighing at least 75 pounds and well seated on a compacted base may be substituted for the compaction base specified in AASHTO T 99. Correcti on for Coarse Particles in t he Soil Compaction Test .................. AASHTO T 99 Family of Curves – One Point Method .................................................... AASHTO T 272 Compaction Standard for Coarse Granular Materials by Use of the Vibratory S pring Load Compactor .............................................................................. Idaho IT 74 Instead of Idaho IT 74, and when approved, determine the maximum dry density of coarse granular material using the following test method: Moisture Density Relations of Soils ........................................................ AASHTO T 180 Method D Determine in place density and percent compaction by the following test methods: In-Place Density and Moisture Content of Soil and Soil Aggregate by Nuclear Methods (Shallow Depth) ........................................ WAQTC FOP for AASHTO T 310 Method B
G.Classes of Compaction and Density Requirements . If the class of compaction is not specified, the Department will require Class A compaction. Before placement, moisten or dry embankment mater ial to a moisture content ranging from 4 percent under optimum moisture content to 2 percent over optimum moisture content as determined by AASHTO T 99 or AASHTO T 180. Scarify existing materials at the top of subgrade in excavations to a depth of 8 inches, moisture condition as specified and compact to Class A compaction.
1.Class A Co mpaction. Compact to Class A compaction embankment and backfill material placed within the roadway prism. Perform the work as specified in Table 205.03- 1. for Highway Construction Page 145 of 71 5 Table 205.03- 1 – Clas s A Compaction (AASHTO T 99 Method C) Material Property Required Compactive Effort Classification 10 percent or more retained on the 3 inch sieve; or more than 30 percent retained on the ¾ inch sieve As specified in 205.03.F.2 Too granular to test Less than 10 percent retained on the 3 inch sieve; and less than or equal to 30 percent retained on the ¾ inch sieve Minimum of 95 percent of maximum dry density . The maximum dry density must be determined as follows: Granular Subbase – Idaho IT 74 Aggregate Base – Idaho IT 74 or AASHTO T 180, Method D, if approved Native soils or Granular Borrow – AASHTO T 99 Method C or AASHTO T 180 Method D Testable material
2.Class B Compaction. Compact e mbankment and backfill material for the top 12 inches of subgrade to the density requirements for Class A compaction. Compact other soil embankment more than 12 inches below the top of subgrade by routing construction equipment uniformly over the entire surface of each layer. The Engineer may require additional compaction if routing of equipment does not provide satisfactory results.
3.Class C Compaction . Compact designated areas under embankments to the density requirements for Class A compaction to a depth of 8 inches. The station limits of Class C compaction will be as specified or as directed. The width of compaction is between the top of subgrade shoulders.
4.Class D Compaction . Compact the embankment and backfill material placed within median areas and on slopes that are outside the roadway prism with at least 1 coverage using approved track type or rubber tired earthmoving equipment. Ensure the fill material is moist before compaction. The roadway prism is shown in the plans. Place the uncompacted embankment material in lifts 12 inches thick or less.
5.Constructio n of Embankment with Other Materials. Compact materials in embankments constructed with materials other than soil or rock as specified.
6.Perform in -place density testing for RAP /granular borrow mixtures at the frequency specified in this section using the following procedure:
a.Establish the roller pattern by using in- place density from an uncorrected nuclear gauge. The required compaction is achieved and final pr ocess rolling is defined as when the final roller pass adds no more than 0.5 pounds per cubic foot to the previous in- place density.
b.Make sufficient additional roller passes to determine that a “false break” or leveling- off point is not used for compaction density.
c.Reestablish the roller pattern when mixture properties in the processed material change and at least every 7,200 square yards of finished surface for each lift. for Highway Construction Page 146 of 71 5 d. Perform additional tests where soil conditions have changed or as determined by the Engineer to ensure the required compaction is achieved.
H.Blasting. Perform rock fragmentation blasting using production and controlled blasting techniques to construct engineered rock cuts. Plan and execute blasting operations in a safe and professional manner. The Engineer will review blasting plan submittals solely for compliance with the contract, plans, and specifications. The Engineer’s blasting plan submittal reviews do not relieve the Contractor’s responsibility for blasting accuracy, adequacy, and safety.
1.Definitions .
a.Production Blasting. Blasting using wider spaced blast holes that typically contain larger explosive charges to expedite movement and fragmentation for rock removal from the main excavation a rea adjacent to the controlled blast line or from the production holes in a rock quarry.
b.Controlled Blasting. Blasting that includes presplit blasting or cushion blasting techniques. Controlled blasting uses closer spaced and carefully aligned blast holes that typically contain lighter charges than production blast holes to produce a stable, smooth surface or shear plane, along the specified line and grade of the final excavated backslope with minimal blast damage. Controlled blast holes are the first row of blast holes, normally located within 24 inches of the top of the staked slope.
c.Presplit Bla sting . Presplit blasting detonates a single line of lightly -loaded, closely spaced, final backslope blast holes either before production blast drilling or before adjacent production blast hole detonation, to produce a highly controlled, smooth cut face.
d.Cushion Blasting. Cushion blasting is similar to presplitting, except that cushion blast hole detonation along the final backslope is immediately after production and buffer blast hole detonation. Where the horizontal distance from the cut face to the existing rock face is less than 15 feet, the Contractor may cushion blast instead of presplitting. With the exception of these criteria, the requirements specified for presplitting also apply to cushion blasting.
2.Regulations. Comply with federal, state, and local laws, regulations, and conditional use permits for blasting operations , including the purchase, transportation, storage, and use of explosive material. Federal regulations include the following:
a.Safety and Health. OSHA, 29 CFR Part 1926, Subpart U.
b.Storage, Security, a nd Accountability. Bureau of Alcohol, Tobacco, and Firearms (BATF), 27 CFR Part 555, Commerce in Explosives.
c.Shipment. DOT, 49 CFR Parts 171 -179, 390- 397.
3.Qualifications. Submit the following for approval at least 21 calendar days before the planned start of drilling and blasting operations :
a.Blaster -In-Charge. Prov ide a Blaster -In-Charge to supervise and direct blasting operations . Blasting material transportation, storage, drilling, loading, detonation, monitoring, reporting, and for Highway Construction Page 147 of 715 operations are under the Blaster -In-Charge’s direct supervision. Provide the following minimum experience and qualifications:
1.A résumé showing at least 5 years of successful experience in similar construction blasting work adjacent to utilities, resi dential or commercial structures , transportation facilities, and critical habitats. Quarry work is not acceptable experience.
2.Include a list of blasting projects with the following information: dates, affiliations to the Contractor, explosive suppliers, and owner reference names and current contact information. Include a brief narrative with each project describi ng controlled blasting techniques, controlling fly rock to within the right of way, scaling, pre- blast surv eys, post - blast surveys, vibration/noise/air overpressure monitoring, blast design, and blasting adjacent to utilities, structures , transportation facilities, and critical habitats, and any major recommended blast plan modif ications made during the projects.
3.Include a complete list of blasting licenses held, current, lapsed, or revoked.
4.Must have been responsible for 3 projects with at least 10,000 linear feet of documented successful presplit holes.
5.Must be in good standing with licensing boards where they hold or have held licenses, regardless of state and federal regulatory agencies governing the use of explosives .
6.Five (5) references with knowledge of qualifications and reliability. Include name, relationship, and current telephone number for each reference.
7.Pre-approved blasting consultants on the Department’s Consultant Term Agreement List for the G8. The blasting co nsultant service category would be acceptable as Blaster -In- Charge.
b.Blasting Crew Personnel. Personnel names and evidence they have completed at least 24 hours of blasting safety training in the last 5 years or have at least 2 years of blasting experience, along with proof of a Federal Employee Possessor Permit for each crew person.
c.Drillers. Names and evidence the drillers are proficient in the drilling methods required to perform the work.
d.Vibration Specialist. Name and résumé showing at least 5 years of experience as a vibration specialist on projects with similar more complex work. Upon receipt of a complete qualifications submittal , the Engineer will have 10 bus iness days to approve or reject the proposed Blaster -In-Charge and other personnel. Do not start work, mobilize equipment, or order materials until t he qualifications submittal has been approved. An alternate Blaster -In-Charge requires Engineer prior -approval with the same submittal requirements as above. Work will be suspended if the Blaster -In-Charge is substituted without prior Engineer approval. The Contractor is fully liable for any additional costs and delays resulting from such work suspensions, with no adjustment in contract time or delay costs.
4.Blasting Plans. A general blasting plan and site- specific blasting plan are required for production and controlled blasting operations . Blasting plans are not required for boulder reduction blasts (e.g., mudcapping, blockholing). for Highway Construction Page 148 of 715 a. General Blasting Plan. Submit a general blasting plan signed by the Blaster -In-Charge for review and approval at least 21 calendar days before beginning drilling and blasting operations . Upon receipt of a complet e submittal , the Engineer will have 10 business days for general blasting plan review and approval. Do not deliver explosives to the project until the general blasting plan is accepted. If any approved general blasting plan revisions are required during construction, resubmit the entire general blasting plan package and allow 10 business days for Engineer review and approval. Include the following information in the general blasting plan:
1.Safety Plan. Include procedures and safety prec autions for transporting, handling, storing, loading, and detonating explosives, conducting pre- blast and post -blast surveys, monitoring blasts, managing misfires, and removing and disposing of excess explosives. Include the following infor mation:
a.Blaster -In-Charge name and current contact information. Certify the Blaster -In-Charge is responsible for the following:
i.Supervising and directing day -to-day drilling and blasting operations , including the transport, storage, handling, and loading of explosives and blasting agents (including primers and initiators). ii. Clearing the blast site before each blast. iii. Responsible person for required reports and documentation for blasting operations (e.g., general blast plan, site- specific blast plans/reports, drill logs, daily explosive material consumption, loss reports, monitoring reports). iv. Checking for misfires and determining the blast site is safe to enter after each blast, including recovery and disposal of misfires or undetonated explosives.
b.Flyrock and blast debris prevention plan, including methods to control flyrock within the right of way, and to prevent personal injury and property dam age. Provide flyrock containment system designs as a contingency.
c.Plan for recovery and disposal of misfires or undetonated explosives.
d.Plan for potential blast site electrical hazards, including lightning detection and protection.
e.Emergency plan to address personal injuries, including hospital and EMS phone numbers.
f.Disposal plan for explosives packing materials.
g.Anticipated work schedule and blast time(s). Blasting is only allowed during daylight hours, within ½ hour after sunrise and ½ hour before sunset.
2.Explosives transportation and storage plan, including:
a.Explosives supplier names, addresses, and telephone numbers.
b.Explosives transport vehicle descriptions, license plate numbers, travel routes, proposed travel hours, and driver qualifications.
c.Magazine and day -box onsite locations.
d.Explosives and accessories inventory system. for Highway Construction Page 149 of 715 (e) Contact information for person(s) responsi ble for security of blasting material and supplies.
3.Area security plan, including explosives and general site security, site communication methods, pre- blast and post -blast signage, audible signaling systems, road closure requirements, and pre- blast notification methods for affected agencies or entities.
4.Manufacturer’s technical and safety data sheets for proposed explosives, primers, initiators, and related blasting devices and acc essories.
5.Pre-blast scaling, pioneered access road, and drilling and blasting operations , bench excavation plans, methods, and equipment lists. Indicate if angle or fan- drilled ho les are anticipated.
6.Production and controlled blasting scaled typical plan and section views, including station and offset limits, maximum blast length, free face, burden, hole pattern, holes per blast, hole inclination, hole depth, hole diam eter, and subdrill depth.
7.Anticipated loading diagram showing type and amount of explosives, primers, initiators, powder factor, charge weight per delay, stemming depth, and material description. Show explosive quantity to be used per delay and per blast.
8.Initiation Method Sequence. Anticipated blast hole- initiation sequence diagram and explanation, including delay times for each blast hole. Identify the delay system type and associated delay periods.
9.Methods for limiting dust a nd noise.
10.Fire prevention and protection plan, including post -blast observers and fire watch duration.
11.Temporary traffic control plan as specified in 105.14.D for Engineer review and approval when blasting operations will occur within 1,000 feet of a roadway. Cover or remove blasting signs when there are no explosives in the area or the area is otherwise secure. The Blaster -In-Charge is required to determine whether road users in the blast ing zone will be endangered by the blasting operation. If there is danger, do not allow road users to pass through the blasting zone during blasting operations.
12.Routine paperwork document templates (e.g., drill logs, ground vibration and air overpress ure monitoring reports, pre- blast and post -blast survey forms ).
b.Site-Specific Blasting Plans (ITD -1006 Blast Plan form and ITD -1008 Blast Report form). Upon Engineer approval of the general blasting plan, submit site -specific blasting plans for each controlled and production blast. The site- specific blasting plan consists of two primary documents: the ITD -1006 Blast Plan and its companion ITD -1008 Blast Report. Submit the ITD - 1006 Blast Plan for Engineer review and approval at least 24 hours before loading any holes. Submit the companion ITD -1008 Blast Report with the same corresponding blast number within 24 hours after the blast. Include the following in the ITD -1006 Blast Plan:
1.Proposed excavation sequence.
2.Proposed blast station limits and plan view, showing how the proposed blast fits into the lift excavation sequence.
3.Top and bottom elevations of each lift. for Highway Construction Page 150 of 715 (4) Scaled drawings for each blast showing access, containment, drill pattern plan and section views, clearing limits, free face, burden, blast hole locations and hole identification number, blast hole spacing, subdrill depths, lift height, blast hole diameters, and blast hole inclinations .
5.Proposed loading diagram for each blast showing powder factor, charge per delay, type and quantity of explosives, primers, and initiators, decking locations, and range of stemming depths for variations within t he drill pattern.
6.Proposed blast hole initiation method and sequence for each blast. Include delay times, delay system, and down hole firing times.
7.Flyrock, air overpressure (noise), and ground vibration control measures .
8.Estimated in- place r ock volume to be blasted. Include the total length of production and controlled blast holes.
9.Drill logs for each blast hole with the following information: date, time, driller name/signature, helper name, hole identification number, hole collar locatio n, hole depth, collar elevation, tip elevation, hole orientation, penetration rate, color and character of cuttings, and other pertinent information or observations. Include geologic features that could affect the blast loading or performance (e.g., groundwater, voids larger than 6 inches, zones of soft or weathered rock, mud pockets, changes in drill effort, loss of drill water, drill rod drops). Provide the drill logs with the ITD -1006 Blast Plan Form.
10.Location and orientation of rock joints , fractures, faulting, bedding planes, or other rock mass structural features.
11.Post-blast rockfall containment designs and procedures.
12.When ground vibration or air overpressure damage is possible to buildings, structures , utilities, and sensitive natural features, include the attenuation study information for the affected items and indicate that the peak particle velocity versus peak frequency will not damage any item.
13.Pre-blast con dition survey records of nearby buildings, structures , utilities, and natural features for potential ground vibration or air overpressure, when applicable.
5.Pre-Blast Condition Survey and Vibration Monitor ing and Control. The Contractor is responsible for damage resulting from blast related ground vibrations and air overpressure. Determine the need for vibration monitoring depending on soil and rock conditions, blasting parameters as outlined in the blasting plans, and proximity of buildings, structures , utilities, and sensitive natural features that may be subject to damage from ground vibrations or air overpressure. If vibration or air overpressure monitoring is required , conform to the follow ing requirements:
a.If not specified in the contract , establish blasting criteria for buildings, structures , utilities, and natural features that conform to federal, state, or loc al regulations. Present blasting criteria in terms of distance of the facility or feature from blasting, maximum allowable peak particle velocity versus peak frequency limits for each structure type, and air overpressure structure damage limits.
b.Conduct a pre -blast condition survey of nearby buildings, structures , utilities, and natural features that could become potentially damaged by blasting- related ground vibrations or air for Highway Construction Page 151 of 715 overpressure. Document the natural frequency of each affected structure or feature. Use a survey method acceptable to the Contractor’s insurance company. Submit the pre- blast condition survey records with the ITD -1006 Blast Plan form.
c.Control ground vibrations a nd air overpressure wit h properly designed delay sequences and maximum allowable charge weights per delay. Verify allowable charge weights per delay by an attenuation study using representative trial blasts and measuring ground vibrations and air overpress ure levels. The attenuation study will enable successful prediction of the peak particle velocity in any component (longitudinal, transverse, or vertical) anywhere on the surface of the structure(s). Conduct test blasts with blast plan modifications that l imit ground vibrations and air overpressure to levels that will not cause damage to nearby buildings, structures , utilities, and/or natural features as determined by the vibration specialist. Submit the attenuation study results and predicted peak particle vel ocity versus peak frequency for each structure.
d.When ground vibration or air overpressure damage is possible, monitor each blast with digital recording seismographs and air overpressure monitoring equipment calibrated within t he last year and approved. Locate monitoring equipment in accordance with the vibration specialist’s directions, placing at least 3 recording stations between the blast area and closest susceptible structures , utilities, or natural features, as well as at least 1 station on each susceptible structure. For ground vibration monitoring, use self -triggering seismographs capable of measuring peak air overpressure and recording particle velocity, displacement, and acceleration for three mutuall y perpendicular components of vibration in the range generally found for controlled blasting . The instrument will contain internal calibration and triaxial orthogonal transducers with flat frequency response from 2 to 250 hertz, with a min imum sampling rate of 1,000 data points per second with sufficient memory to store the full blasting sequence and their locations. Seismographs must be capable of producing a permanent digital time history file for each ground motion episode. Ensure blasti ng operati ons incorporate collected data and findings from vibration and air overpressure monitoring by having the vibration specialist interpret seismograph and air overpressure records. Submit the interpreted seismograph and air overpr essure records with a certifying signature by the vibration specialist. If actual peak particle velocity versus peak frequency measurements exceed those predicted for a structure, adjust the site- specific blast plan for the actual structural response to th e blasting. Such adjustments may include changes to pattern, loading, timing, flyrock measures. Record each blast using digital video equipment from 2 locations that clearly show the entire proposed blast site.
6.Test Blasting . Before beginning drilling for production or controlled blasting, demonstrate acceptable performance of a site- specific blasting plan for both a production blast and a controlled blast, by drilling, blasting, and excavating a test blast up to 100 lineal feet in lengt h, as measured along roadway centerline, with the proposed containment measures in- place. Production and controlled drilling and blasting operations are not allowed until test blasting is complete and accepted by the Engineer. Conduct test blasting at Engineer -approved locations within the planned excavation area. Excavate shot rock to expose the entire back slope for test blast evaluation. Space blast holes for controlled blasting (presplit or cushion) no more than 30 inches apart for the initial test blast. Adjust the spacing as necessary to produce acceptable results. Use the accepted spacing for future controlled blasting, or subsequent test blasts if necessary. for Highway Construction Page 152 of 715 A test blast is unacceptable when any of the following occurs:
a.Slopes are unstable.
b.Slopes exceed overbreak tolerances within the limits of the excavation, as specified, or as determined by the Engineer for the site geology.
c.Non-planar, irregular surface with overhangs, protrusions, ridges, or ledges are created.
d.Excessive blast damage occurs within the limits of the excavation, as specified, or as determined.
e.Poor fr agmentation results in oversize mater ial requiring secondary blasting and rehandling.
f.Safety of the public is jeopardized.
g.Property or natural features are endangered.
h.Excessive or uncontrolled flyrock is generate d and not contained within the right of way.
i.Excessive ground vibration or air overpressure occur where damage to buildings, structures , utilities, or natural features is possible.
j.Desired slope or rock face conditions are not produced. Revise the site- specific blasting plan and conduct additional test blasts when a test blast is unacceptable. Production and controlled drilling and blasting may begin only after site- specific blasting plans are accepted. The Engineer has the authority to suspend the Contractor's blasting operations at any time throughout construction and require additional test blasts when the Contractor produces unacceptable results.
7.Blasting Operations .
a.General. Use explosives and initiating devices that are les s than 1 year old or in accordance with the manufacturer’s recommendations for specialty products. Blast holes are not allowed to remain loaded with explosives overnight, but must be detonated the s ame day they are loaded. Stage explosives at locations dir ected by the Blaster -In-Charge, and as approved. Properly dispose of explosive packing materials and remove them from the project site before each blast. Establish survey control nec essary for the drilling to meet the required horizontal and vertical control tolerances. Establish a survey control method for transferring the blasting plan grid pattern on the accepted site- specific blasting plan form to the field. Paint or stake the drill hole identification number and collar elevation next to each drill hole for field identification. Provide the drill logs with the ITD -1006 Blast Plan form for every blast. Ensure blast holes are drilled to the correct dept h and free of obstructions for the entire depth before placing charges. Take necessary precautions when placing charges so caving of material from the walls of the holes and the hole collar will not occur. If drill hole conditions vary from dry to wet, use appropriate explosive type(s) and/or blasting accessories to accomplish the specified results. Protect blast holes with a temporary plug to keep overburden, drill cuttings, or other foreign material from falling into the holes after drill ing. Fill unused drill holes with ½” -minus crushed stone or approved materials. for Highway Construction Page 153 of 715 Mitigate uncontrolled gas pressure loss during blasting and excessive blast noise by stemming the upper portion of blast holes with appropriate dry granular material passing the ½ inch sieve. Do not stem holes with dr ill cuttings. Blast according to the accepted site- specific blasting plan. Use blasting mats, rockfall containment systems, and other protective devices to prevent damage to surroun ding features and contain flyrock within the right of way. Stop drilling and blasting operations immediately and perform additional test blasting when any of the below unacceptable results occur :
1.Slopes are unstable.
2.Slopes exceed overbreak tolerances within t he limits of the excavation, as specified, or as determined by the Engineer for the site geology.
3.Non-planar, irregular surface with overhangs, pr otrusions, ridges, or ledges are created.
4.Excessive bl ast damage occurs within the limits of the excavation, as specified, or as determined.
5.Poor fragmentation results in oversize material requiring secondary blasting and rehandling.
6.Safety of the public is jeopardized.
7.Property or natural features are endangered.
8.Excessive or uncontrolled flyrock is generated and not contained within the right of way.
9.Excessive ground vibration or air overpressure occur where damage to buildings, structures , utilities, or natural features is possible.
10.Desired slope or rock face conditions are not produced. The Engineer has the authority to suspend the Contractor's blasting operations at any time when any of the above unacceptable r esults occur . Remove or stabilize cut face rock that is loose, hanging, or potentially dangerous after each blast. Scale by hand or machine methods as approved. Do not drill the next lift until slope stabilization and blast cleanup work is complete. Scaling and stabilization requirements also apply to excavated soil slopes, and ripped or blasted rock slopes associated with pioneer and access roads.
b.Production Blasting. Drill a lighter -loaded buffer row of production holes on a parallel plane adjacent to the controlled blast line to prevent blast damage to the final backslope face when performing controlled blasting . Detonate product ion holes in a controlled delay sequence. Drill production blast holes on the pattern in accordance with the accepted site- specific blast plan within two drill hole diameters of the planned collar location. If more than 5 percent of the drill hole collars in a lift are out of tolerance, fill each hole outside of the location tolerance with ½” - minus crushed stone, or approved material, and redrill at the proper location, at no additional cost to the Department. Drill production blast holes to the design depth on the accepted site- specific blast plan. Redrill shallow holes to the proper depth if more than 5 percent of the production blast holes in a lift do for Highway Construction Page 154 of 715 not conform to the design depth requirements . Except when subdrilling, do not drill pr oduction blast holes below the controlled blast hole base plane.
c.Controlled Blasting. Use angle - or fan- drilled holes for pioneering the tops of rock cuts and preparing working plat forms. Use equipment or methods approved by the Engineer for areas not accessible to track drill equipment. Remove potentially dangerous boulders or other material located beyond the excavation limits before drilling controlled blast hol es. Removal of material located beyond the excavation limits is extra work (104.02) . Before drilling, completely remove overburden, soil, and loose or decomposed rock along the top of the excavation for a distance of at least 30 feet beyond the end of the production hole drilling limits, or to the end of the cut. Use controlled blasting to form the final backslope of rock cuts where the design slope ratio is 3/4H:1V or steeper and the slope height is more than 10 feet above the ditch grade. Control drilling operations by using equipment and techniques that accurately control the drill angle as it enters the rock, to ensure that no hole deviates from the excavated backslope planned final plane by more than 9 inches from the pr oposed spacing and alignment, either in the parallel or normal direction. If more than 5 percent of the holes exceed the variance, reduce the lift height and modify drilling operations until the holes are within tolerance. The maximum all owable horizontal offset bench width for drill equipment clearance for multi -lift blasts is 2 feet. Adjust the initial controlled blast hole locations to account for additional width needed for planned offset bench es. Remove benches during excavation of the next lift to a slope of at least 45° below horizontal. The Department will not pay for presplit holes exceeding these tolerances. Drill controlled blasting holes a maximum of 3 inches in diameter and within 3 inches of the staked collar location. Fill and redrill blast holes outside of the location tolerance when more than 5 percent of the hole collars in a lift are outside of the location tolerance. Use ½” -minus, crushed stone or other approved material to fill the blast holes before redrilling. Drill the controlled blast hole line at least 30 feet beyond loaded production holes or to the end of the cut. Do not exceed 30 feet for bench heig ht or drill hole length, unless longer holes are approved by the Engineer and can be successfully demonstrated in a test blast. Limit subdrilling to one- half of the hole spacing or 24 inches, whichever is deeper. Do not use bulk ammonium nitrate and fuel oil (ANFO) for control led blasting. Use only standard explosives manufactured specifically for controlled blasting in controlled blast holes, unless approved. Use explosives in controlled blast holes with a maximum diameter of no greater than one- half the contr olled blast hole diameter. As long as satisfactory presplit slopes are obtained, the Contractor may either detonate the presplit blasting holes forming the final backslope face before drilling for production blasting, or detonate the presplit blasting holes within the same production blast event, provided the presplitting drill holes are detonated at least 25 milliseconds ahead of the adjacent production blast holes . for Highway Construction Page 155 of 715 If blasting operations cause fracturing of the final rock face, repair or stabilize it in an approved manner at no cost to the Department. Repair or stabilization may include removal, rock bolting, rock dowels, or other slope stabiliz ation techniques, as approved.
8.Reporting.
a.Post-Blast Report (ITD -1008 Blast Report Form). For each site- specific blasting plan’s ITD- 1006 Blast Plan form, submit a post -blast report on the ITD -1008 Blast Report form with the same correspondi ng blast number. Submit the complete blast report within 24 hours following a blast and before loading for the next blast. The purpose of the ITD -1008 Blast Report is to record the actual drill hole and loading configuration that took place in the field versus what was planned in the ITD -1006 Blast Plan form. The ITD -1008 Blast Report also serves as the official record for measurement and payment for controlled blasting. Include the following in the ITD -1008 Blast Report :
1.Brief blast res ults narrative (e.g., overbreak, blast damage, noise levels, flyrock, drill trace retention, fragmentation, material containment, material rehandling requirements, misfires).
2.Proposed changes for future blasts that will improve res ults (e.g., pattern, loading, timing).
3.Proposed repairs or stabilization plan for unstable or blast damaged slopes.
4.Blast hole depth measurements verified by the Blaster -In-Charge.
5.Blast layout with station and offset limits, plan and section views, drill pattern, free face, burden, blast hole spacing, blast hole diameters, blast hole angles, lift height, and sub drill depth.
6.Actual loading diagram with type and amount of explosive, primers, initiators, and stemming depth.
7.Actual blast hole- initiation sequence, including delay times and delay system in each blast hole.
8.Trade names and sizes of explosives, primers, and initiators used.
9.Measurement of any overbreak quantities following lift mucking.
10.Ground vibrati on and air overpressure records as specified in 205.03.H.8.b.
11.Daily explosive material consumption and report of loss report (e.g., ATF daily summary of magazine transactions) with Blaster -In-Charge signature.
12.Blast loading and detonating date and time.
13.Blaster -In-Charge name and signature.
b.Monitoring. Submit digital videos within 24 hours after each blast. If vibration and/or air overpressure monitoring is required, submit a vibration and air overpressure report for review within 24 hour s following a blast and before loading for further blasting. Include the following:
1.Vibration or air overpressure recording station type used and instrument identification numbers. for Highway Construction Page 156 of 71 5 (2) Name of vibration specialist observing the blast and interpreting vibration and air overpressure data.
3.Blast identification number and blast location.
4.Distance and direction of ground vibration and air overpressure recording stations from the blast area.
5.Type of material ground vibration recording stations were sitting on at the blast time.
6.Maximum applicable charge weight per delay.
7.Peak displacement, particle velocity, and frequency recorded at each ground vibration sensor location.
8.Peak overpressur e recorded at each air overpressure sensor location.
9.Dated and signed copy of instrument records.
10.Post- blast condition survey noting changes from the pre -blast survey.
11.Comments on blasting success in terms of adherence to established ground vibration or air overpressure criteria and management practices. When failing to meet ground vibration and air overpressure criteria and management requirements, submit proposed changes to future site- specific bl asting plans t hat will produce acceptable results. Submit the final post -blast survey reports with property owners’ acknowledgement of receipt (e.g., email, letter). Repair damage to public or private property caused by the use of explosives as a first order of work. The Department will not pay for damage repairs .
c.Close -out. Submit a written statement signed by the Blaster -In-Charge certifying:
1.Blast hole s loaded with explosive material have been either detonated or unloaded and disposed of properly.
2.Blasting is complete and explosive material has been removed from the project site.
I.Guardrail Terminal Grading. Place aggregate in sufficient quantities to match the plans. Ensure grading is sloped at 10:1 or flatter and ensure foundation tubes and terminal struts will not protrude more than 4 inches. Compact the guardrail terminal area to meet Class D requirements or as directed. Broom adjacent pavement to remove aggregate.
J.Dust Abatement . Apply water at a sufficient rate and frequency to control dust pollution to the satisfaction of the Engineer. When magnesium chloride is required, apply as recommended by the manufacturer.
205.04 Method of Measurement.
The Engineer will measure acceptably completed work as follows:
1.Excavation , borrow , and granular borrow will be by the cubic yard in its original position from field survey or photogrammetric cross -sections, using the average- end-area method with no correction for curvature, or by the ton. for Highway Construction Page 157 of 71 5 2. Where it is impractical to measure material by the average- end-area method or in its original position, alternate practical methods with appropriate adjustments may be used. The total will not include the volume of material used for purposes other than as directed. A measurement will not be made for rock excavation made below the roadbed, unless the excavation is required or directed. A measurement will not be made for borrow replaced by unauthorized rock or soil excavation below roadbed.
3.Channel change excavation will be measured only for excavation necessary to construct the channel or ditch from established bank elevation to flowline grade. Earthwork necessary to construct the cut or fill to bank elevation will be included in the roadway quantities . Overbreak will not be included in the measurem ent of excavation.
4.Water for dust abatement and magnesium chloride brine for dust abatement will be per thousand gallons (MG), by means of calibrated tanks, distributors, or accurate water meters.
5.Controlled blasting will be measured by the linear foot of accepted drilled holes as recorded on the Blast Report (Form ITD-1008).
6.When granular borrow is measured on the weight basis, the water in excess of 7 percent of the dry weight of the material will not be measured. The Department will correct the measured quantity for moisture content in accordance with AASHTO T 255.
7.Quantities of granular borrow replaced by other approved materials (e.g., RAP) is considered as a portion of granular borrow .
8.Acceptable shoulder grading work will be measured by the mile for each direction of travel.
9.The Engineer will measure acceptable soft spot repair by contingency amount.
10.Shoulder aggregate will be measured by the cubic yard or by the ton.
11.Guardrail terminal grading will be measured by each.
12.Process old road will be by the lump sum.
205.05 Basis of Payment .
The Department will pay for accepted quantities as follows: Pay Item Pay Unit Excavation .............................................................................................. CY Excavation Schedule No.____ ................................................................ CY Controlled Blasting ................................................................................. Linear FT Channel Change Excavation .................................................................. CY Borrow .................................................................................................... CY or Ton Granular Borrow ..................................................................................... CY or Ton Water for Dust Abatement ...................................................................... MG Excava tion and Repair of Soft Spot s ...................................................... CY Shoulder Aggregate ................................................................................ CY or Ton for Highway Construction Page 158 of 71 5 Shoulder Grading ................................................................................... per mile Soft Spot R epair ..................................................................................... CA Guardrail Terminal Grading .................................................................... Each Process Old Road .................................................................................. LS Magnesium Chloride Brine for Dust Abatement ...................................... MG Embankment and backfill are incidental and the work included in other contract pay items . The Department will pay for removal and disposal of unsuitable material from below the roadbed under excavation and repair of soft spots. Excavation and repair of soft spots includes excavation, drying, and compaction of in-place material. If approved, the Department will pay for replacement material under the applicable contract pay item or as extra work. The Department will not pay for replacement material if used for the Contractor’s convenience. The Department will pay for removal of slides, slumps, settlements, and associated work not caused directly by the Contractor’s operations at the contract unit price for excavation where the slide occurred or as extra work (104.02) . The Department will pay for water the Engineer orders for controlling dust for safety of the traveling public, for the safety of people residing near the project site, to protect crops from possible dust damage, or that is applied in the public interest at the dust abatement contract unit price. The Department will pay for excavation that must be stockpiled or stored before final placement, including topsoil , at the contract unit price for each handling approved, unless paid for as another item of work for the second handling. The Department will pay for RAP, if used as granular borrow, at the granular borrow contract unit. The Department will not pay for rock overbreak. Blasting is incidental and included in other roadway contract pay items . Blasthole locating and depth control is incidental to the blasting work. The Department will pay for post -blast cut slope stabilization or scaling necessitated by the rock structural geology as extra work (104.02) . The Department will not pay for post- blast cut slope stabilization or scaling made necessary because of the Contractor's blasting operations . The Department will pay for the over -drill limits made necessary for offset benches in m ulti-lift cuts as specified in 205.03.H.7.c. Material removal and sweeping of the roadway surface is considered incidental to this item. Granular subbase, ¾ inch aggregate for untreated base, HMA pavement , tack, subgrade separation geotextile, and biaxial geogrid will be paid under their respective pay items . Otherwise, pay by force account if these pay items are not in the contract . Coarse aggregate for concrete will be paid by force account . for Highway Construction Page 159 of 71 5 The Department will accept granular subbase , untreated aggregate for base , coarse aggregate for concrete, and HMA including compaction by ITD -850, ITD -854, and/or ITD -855 form(s) as applicable, documented once per soft spot. Work required by, and associated with, the Blaster -In-Charge is incidental to controlled blasting. Slope finishing is incidental and the work included in other contract pay items . Surveys associated with blasting including surveys for drill holes are incidental. Reducing oversize material from rock excavations are incidental. Payment for controlled blasting will be based on accepted quantities documented on the ITD -1008 Blast Report form. Guardrail terminal grading materials will be pa id for under their respective items unless otherwise noted. for Highway Construction Page 160 of 715 SECTION 206 - RESERVED
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 175–195 of 768.