NMDOT 2019 NMDOT Standard Specifications for Highway & Bridge Construction Section 203 Excavation, Borrow, and Embankment — Full Text

SECTION 203: EXCAVATION, BORROW, AND EMBANKMENT

203.1 Description

This Work consists of performing excavation in soil and rock M aterial, providing borrow Material, constructing Embankmen t, hauling, disposing, placing, and compacting Materials.

203.2 Materials

The Department will provide geotechnical and/or pavement inves tigation data in the Contract documents, when avail able. The Contractor shall use t he data for information only.

203.2.1 Material Classifications 203.2.1.1 Rock Excavation

Rock excavation is Material t hat meets one (1) of the followin g field test criteria: 1. Ripping Test. Material that cannot be broken down with two passes parallel to construction centerline with a s ingle tooth ripper mounted on a crawler-type tractor in low gear with a minimum net flywheel power rating of 255 hp; 2. Seismic Test. Material that has a seismic velocity greater than 6,000 ft/s. The Contractor shall submit the qualifications of the individual pe rforming and interpreting the seismic testing to Project Manager for approva l a minimum of 14 Days prior to testing. Perform the Ripping Test to resolve dif ferences in Material classification if seismic veloc ities fall below 6,000 ft/s; or 3. Handling Test. Boulders or detached stones having a volume greater than one ( 1) yd 3 that cannot be readily broken down with excavation Equipment.

203.2.1 2 Unclassified Excavation

Unclassified excavation shall consist of the excavation of all Materials other than rock excavation obtained within the Right of Way. Suitable Material obtained from unclassified excavation shall be used for ar eas that require Embankment.

203.2.1 3 Borrow

Borrow shall consist of Contractor provided suitable Embankmen t Materials obtained from an approved source outside the Right of Way, unless otherw ise specified in the Contract. The Contractor shall only utiliz e borrow when the following con ditions are met, unless approved otherwise by the Project Manager: 1. All unclassified excavation Material has be utilized in the Contractor’s current phase of construction; 2. The Contractor has requested to begin Borrow operations and the Project Manager has concurred; and 3. Embankment areas that require borrow have been bladed and cr oss sectioned by the Contractor and provided to the Project Manager. B o r r o w M a t e r i a l p l a c e d w i t h i n t w o ( 2 ) F t , v e r t i c a l l y a n d l a t e r a lly, of final Subgrade elevations shall meet the design R-Value as shown in the Contra ct. Prior to bor row operations the Contractor shall perform R-value testing in accordance with AASHTO T-190 at the best fit exudation pressure of 300 psi at each borrow source. This info rmation shall be submitted to the Project Manager with the request to begin borrow operations . During borrow placement, if the Project Manager observes c hanges in soil properties, includ ing gradation, plasticity limits, Section 203: Excavation, Borrow, and Embankment Page 100 and/or additional soil characteristics, then, at the Project Ma nager’s request, additional AASHTO T-190 tests may be required, at the Contractors expense. When Work conforming to Section 306, “Portland Cement or Lime Treated Subgrade” is specified in the Contract, the Contractor shall perform sulfate testing in accordance with AASHTO T290 at each borrow source. Sulfate content shall be de termined and reported as parts per million (ppm). Soils with sulfate contents equal to or greater than 2,000 ppm shall not be used as borrow.

203.2.1 4 Unstable Subgrade Stabilization

See Section 203A, “Unstable Subgrade Stabilization”, when spec ified in the Contract.

203.2.1 5 Unsuitable Material

Unsuitable Material includes or ganic Materials, frozen lumps, ice, and soils such as peat, shale, gypsum or other soil or rock Materials that may degrade with time, or are contaminated. Suitable Material that is unstable may be reworked to create a stable platform as directed by the Project Manager. Material below embankment and areas identified by the Project Manager and determined to be unsuitable shall be excavated and disposed of in accordan ce with Section 107, “Legal Relations, Environmental Requirements, and Responsibility to th e Public” unless otherwise specified in the Contract. When unsuitable Material is remo ved and disposed of, the resul ting void shall be filled with Material suitable for its planned use as directed by the P roject Manager. Such suitable Material shall be placed and com pacted in accordance with this Specification.

203.3 Construction Requirements

203.3.1 General

The Contractor shall finish excavation and Embankment for the Roadway, intersections, and entrances to reasonably smooth and uniform surfaces. The C ontractor shall not remove Materials from the Project lim its without the approval of the P roject Manager. The Contractor shall ensure Borrow Material placed within the top two (2) Ft of the finished Subgrade meets the minimum design R-value. The Contractor shall preserve the Materials below and beyond t he lines and grades while conducting excavation operations. Before beginning excavation, grading, and Embankment operations, the Contractor shall perform the necessary clearing and grubbing in accordance with Section 201, “Clearing and Grubbing.” The Contractor shal l notify the Project Manager before opening excavation or borrow areas. The Contractor shal l take cross section elevations of the ground surface before opening excavation or b orrow areas. The Contractor shall terminate operations in the immediate are a of environmental or Cultural Resources not listed in the Contract, until the Depart ment reviews and completes appropriate mitigation actions i n accordance with Section 107.1 2, “Environmental, Hazardous Materials and Cultural Resource Discoveries.”

203.3.2 Excavation

Section 203: Excavation, Borrow, and Embankment Page 101 Within cut sections, the Contractor shall remove excavated Mat erial from the limits of the cut section to the Subgrade elevation for the width of the Road bed. The Contractor shall finish Roadbed cut sections to a smooth and uniform surface. The Cont ractor shall remove unsuitable Material below finis hed Subgrade in accordance with 203.2.1.5, “Unsuitable Material.” The Contractor shall take cross-sectional measureme nts after the removal of unsuitable Material.

203.3.3 Rock Cuts

The Contractor shall perform proper drilling and blasting oper ations in accordance with the specified practices. When r equired, the Contractor shall p erform controlled blasting of rock excavation to produce a clean face on the excavated cut. The Contractor shall ensure subsequent blasting and excavation operations do not affect pre viously excavated faces. The Contractor shall not excavate more than six (6) inches below th e specified Subgrade elevation for Roadbed cuts in rock, unless directed otherwise. The Contr actor shall not leave undrained pockets on the Roadbed surface. The Contractor shall place and compact Base Course on the rock cut foundation in accordance with Section 303, “Base C ourse.”

203.3.3 1 Blasting Requirements

The Contractor shall use controlled blasting to establish a sp ecified backslope with minimal blast damage, and produc tion blasting to facilitate exc avation. Before the start of blasting, the Contractor shall notify adjacent property owners, occupants and utility owners.

203.3.3 1.1 Definitions

Blasting Operations. Activities related to blasting including, but not limited to th e following: 1. Collaring and drilling blast holes; 2. Preparing, fixing, loading, and firing explosive charges; 3. Assessing the blast after detonation; and 4. Handling misfires. Buffer Row. The first row of production blas t holes immediately adjacent an d drilled in a plane parallel to the controll ed blast line. The explosive l oad in the buffer row should be reduced from standard production loads to minimize damage to th e backslope of the final excavation. Controlled Blasting. The controlled use of explosives and blasting accessories in carefully spaced and aligned blast holes to provide a free surf ace or shear plane in the rock along the specified backslope, and to limit fly rock, permanent ground displacement, air concussion, and overbreak. Contr olled blasting methods include pre-splitting and cushion blasting. Cushion Blasting (Trim Blasting). The simultaneous detonation of one (1) line of blast holes along a specified excavation backslope after the main exc avation is complete. This method is performed to trim the excavation to the final backslo pe. Final Line (Controlled Blast Line). Refers to the row of controlled blast holes drilled in the plane of a specified excavation backslope. The controlled blast holes drilled in this plane constitute the basis for payment under the Controlled Blasting pay item. The Department considers the blast holes drill ed in front of the final line bl ast holes to be production blast holes, which are Incidental to the Rock Excavation pay item. Pre-Splitting. The simultaneous detonation of one (1) line of blast holes dril led along a specified excavation backslope bef ore production blast holes ar e fired. Production Blasting. Fragmentation blasting in t he main excavation area.

203.3.3 1.2 Submittals

203.3.3 1.2.1 Blaster in Charge

The Contractor shall not begin drilling or blasting Work until the Project Manager approves of the Blaster in Charge. The Contractor shall submit the name and qualifications of the proposed Blaster in Charge to the Project Manager for appro val at least 30 Days before the delivery of explosive Material to the Project. The Contrac tor shall provide the following information: 1. Proof of a license by the applicable State and/or local regu latory agencies to possess, transport, and use explosives; and 2. A list of, and references, for at least three (3) blasting P rojects, of sim ilar complexity, successfully completed within t he previous five (5) years. The Blaster in Charge must be on site during blasting operatio ns.

203.3.3 1.2.2 Blasting Plans

The Contractor shall submit a General Blasting Plan to the Pro ject Manager for each cut that requires blasting, at least two (2) weeks before the start of drilling and blasting operations on a specified cut. The Contractor shall provide the following information in the General Blasting Plan: 1. Description of the proposed blasting operation; 2. Preliminary design criteria for production and controlled bl asting, including blast hole depths and patterns; and 3. Details regarding the proposed explosives and blasting acces sories. The Contractor shall submit a Detailed Blasting Plan at least 48 H before an individual blast. The Contractor shall provide the following information in the Detailed Blasting Plan: 1. Station limits of the proposed location of the blast, includ ing the bench elevation, if applicable; 2. Date and time the blasting will occur; 3. Required removal of overburden, if applicable; 4. Plan and cross section diagrams of proposed drill pattern fo r controlled and production blast holes, including buffer rows, free face, burde n, blast hole spacing, blast hole diameters, blast hole angles, lift height, and subdr ill depth. Draw these Plans and cross sections to scale; 5. Loading diagram showing the type and amount of explosives, p rimers, and initiators; and the location, depth, and type of stemming; 6. Initiation sequence of cont rolled and production blast holes , including Delay times and the Delay system; and 7. Manufacturer’s data sheets fo r the explosives, primers, and initiators to be used. The Contractor shall submit the blasting Plans to the Project Manager for review and Acceptance. The Project Manager will review and provide commen ts to the Contractor. The Section 203: Excavation, Borrow, and Embankment Page 103 Contractor shall submit revisi ons to the blasting Plans for fin al review and Acceptance. The Contractor shall not proceed with drilling and blasting operati ons related to a General Blasting Plan or loading of blast holes ass ociated with a Detailed Blast ing Plan without written notice. The Contractor shall cease blas ting operations and submit revi sed blasting Plans if the Department determines that the b lasting operations are causing property dam age in and beyond the Right of Way.

203.3.3 1.2.3 Blasting Records

The Contractor shall prepare and submit to the Department a Bl asting Record for each blast, on the Day of the blast. The Contractor shall provide t he following information in a Blasting Record: 1. Actual dimensions of the shot, including blast hole diameter s and depths, burden, spacing, subdrilling depths, stemm ing, powder loads, powder fac tors, and timing; 2. A drawing or sketch showing the direction of the face and th e physical shot layout; 3. The location of the blast in relation to Project stationing and elevation; 4. The date and time of loading and detonation; 5. The name and signature of the person responsible for loading and firing; 6. Comments by Blaster in Charge regarding misfires, fly rock o ccurrences, unusual results or effects; and damage to existing facilities, adjacent property, or completed Work; 7. Vibration and blast monitoring results; and 8. Any complaints received due to the blasting.

203.3.3 1.3 Explosives

The Contractor shall transport, store, handle, and use explosi ves in accordance with applicable federal, State, and local laws and regulations. The Contractor shall purchase explosives and accessory devices from industry recognized Suppl iers and manufactures. The Contractor shall use explosives and accessory devices in accord ance with manufacturer instructions. The Contractor s hall not use expired products. The CFR specifies responsibility for the following federal age ncies regarding the administration of regulations inv olving explosive Materials: 1. Bureau of Alcohol, Tobacco, Fi rearms, and Explosives (ATF). Storage and accountability of record keeping and security in accordance wit h 27 CFR part 555; 2. OSHA. Transportation, worker safety, and health in accordan ce with title 29 CFR; storage and safe blasting practices in handling and use in acco rdance with 29 CFR part 1926.900 et seq; and 3. Federal Department of Transportation (USDOT). Transportatio n and public safety, 49 CFR. The fire marshal, sheriff, or o ther local officials, may have additional regulations for explosive Materials.

203.3.3 1.4 Safety

The Contractor shall follow safe practices, including the foll owing: 1. Federal, State, and local regulations pertaining to the tran sportation, storage, and use of explosives must be strictly followed; Section 203: Excavation, Borrow, and Embankment Page 104 2. When required, the Blaster in Charge must obtain a blasting permit from the local regulatory agency before blasting; 3. Only persons authorized and qualified based on training and experience will handle and use explosives; 4. No person will smoke; carry mat ches or other flame producing devices; or carry firearms or loaded cartridges wh ile in or near a motor vehicle that is transporting explosives; 5. Keep track of explosives at a ll times. Explosives must be s tored and locked in an approved magazine facility in accordance with the applicable pr ovisions of the Department, ATF, and OSHA until used in blasting; 6. Post appropriate signs in the required areas and vehicles in accordance with federal regulations; 7. Safely station the necessary guards or flag persons on Highw ays during blasting to control Highway traffic; and 8. Before starting Work in the cut, observe the entire blast ar ea for at least five (5) minutes after each blast. Remove potentially dangerous rocks o r other Material located beyond the excavation limits. Cease blasting operation s if the required slopes are not stable, or if the safety and convenience of the public are being jeopardized.

203.3.3 1.5 Vibration Risk Survey

For each cut that requires blasting, the Contractor shall perf orm a vibration risk survey of nearby buildings, Structures, utilities, water supplies, or env ironmentally sensitive areas that may be at risk of blasting or construction damage. The Contrac tor shall perform the vibration risk survey in accordance with S ection 617, “Vibration Monitori ng and Video Taping.” The Contractor shall obtain written approval for the vibration risk survey from the Project Manager before drilling blast holes.

203.3.3 1.6 Blasting Test Sections

The Contractor shall demonstrate the adequacy of proposed Blas ting Plan with a blasting test section(s) for Material of different geologic characterist ics. For Projects involving multiple cuts in similar geologic Materials, the Project Manager may red uce the requirement for a blasting test section in each cu t. Blasting test sections incl ude drilling, blasting, and excavating cut sections approximately 100 Ft long to determine the optimal combination of method, blast hole spacing, and charge. When field conditions warrant, the Project Manager may direct the Contractor to use test section lengths less than 100 Ft long. Blasting test section requirements include the following: 1. The Contractor shall perform the blasting test section in ac cordance with Section

203.3.3 1, “Blasting Requirements.” The Contractor shall prepa re and submit a

Detailed Blasting Plan for the test section to the Project Mana ger at least 48 H before the planned time of the blast. The Contractor shall not start blasting the test section until the Project Manager A ccepts the Detailed Blasting Plan; 2. Unless the Contractor’s Detailed Blasting Plan indicates oth erwise, the Contractor shall begin the tests with the controlled blast holes spaced at 30 inches; and 3. After blasting, the Contractor shall remove a sufficient amo unt of Material from the test section to determine if the blast hole diameter, blast hol e spacing, and amount of explosives are adequate to provide the required backslope. The Contractor shall not continue drilling of the test section area until the test s ection is excavated and the Department evaluates the results. If, at any time during the progress of the main blasting opera tion, the methods of drilling and blasting do not produce the desired results, the Contractor shall revise and retest the blasting techniques until a te chnique produces the required res ults. The Department will consider the results to be unsatisfactory if: 1. There is an excessive amount of breakage beyond the indicate d lines and grade; 2. There is excessive flyrock; 3. The final backslope within the specified tolerances is not u niform or overhangs are created; 4. Ground vibration and air blas t levels exceed limits as state d in Section 617, “Vibration Monitoring and Video Taping;” 5. There are violations of other requirements of the Specificat ions; 6. The slopes are unstable; 7. The safety of the public is jeopardized; and 8. Property or natural features are endangered.

203.3.3 1.7 Blasting Execution

203.3.3 1.7.1 Notification and Schedule

The following requirements will apply to the notification and scheduling of blasting procedures: 1. The Contractor shall coordinate blasting operations with the Project Manager and notify the Project Manager a minimum of 1.5 H before the blast. The Contractor shall provide a one (1) hour timeframe for the blast. For exam ple, if the Contactor notifies the Project Manager by 9:00 a.m. the blast may occur b etween 10:30 a.m. and 11:30 a.m.; 2. The Contractor shall provide notice to the required federal, State, and local agencies before each blast, as requir ed by the blasting permits; 3. The Contractor shall notify occupants of buildings and owner s of Structures and utilities of the blast time and location at least 48 H before t he start of drilling or blasting; and 4. The Contractor shall detonate blasts at the planned time, un less approved otherwise by the Project Manager.

203.3.3 1.7.2 General Requirements

The Contractor shall cover the blast area with blasting mats, soil, or another equally serviceable Material, before firi ng blasts in areas where flyin g rock may result in personal injury or damage to property or the Work.

203.3.3 1.7.3 Controlled Blasting Requirements

The Contractor shall perform controlled blasting in accordance with the Detailed Blasting Plans that produced Acceptable results in blasting test section s. The Contractor shall perform control blasting using either p re-splitting or c ushion blasting in accordance with the following requirements: 1. If the overburden does not support the drill holes, complete ly remove the overburden soil and loose rock along the top of the cut to expo se the rock surface before drilling the controlled blast holes; Section 203: Excavation, Borrow, and Embankment Page 106 2. Mechanically monitor the blast hole angles; 3. Drill and space blast holes wit h a nominal diameter from two (2) inch to three (3) inch, in accordance with the blasting test sections or the resu lts achieved in similar geologic Materials. Do not exceed three (3) Ft; 4. Use proper Equipment and technique to ensure that no blast h oles deviate from the plane of the backslope shown in the Plans by more than eight (8 ) inches, parallel or normal to the slope. The Department will not pay for blast hol es exceeding these limits unless the Project Manager approves the obtained slopes; 5. Drill the controlled blast holes at the required slope incli nation, to the full depth of the cut, or to a pre-determined stage elevation. The maximum d rill depth is 30 Ft. Use shallower holes if the directional control is inadequate. If more than five percent (5%) of the controlled bl ast holes are misaligned in an y one (1) lift, reduce the height of the lifts until the eight (8) inch tolerance is m et. The length of controlled blast holes may be in crementally increased once sati sfactory directional control and blast results are demonstrated; 6. Drill unloaded and un-stemmed guide holes to the same diamet er, in the same plane, and to the same tolerance as the controlled blast holes; 7. The Department will allow a ma ximum offset of 24 inches from the bottom of each lift to allow for drill Equipment clearances, when the cut requ ires more than one (1) lift. Begin drilling the control blast hole at a point that al lows the necessary offsets, and adjust at the start of lower lifts as necessary to compensa te for drift in the upper lifts; 8. Do not use horizontal blast holes for controlled blasting; 9. Use explosive charges, detonating cord, and other items nece ssary for the blasting operation in accordance with the manufacturer’s recommendations and instructions; 10. Before placing charges, ensur e the hole is free of obstruct i o n s . U s e c a s i n g i f necessary to prevent the walls o f the hole from collapsing; 11. Use only standard explosives manufactured especially for th e type of controlled blasting (cushion or pre-splitti ng). Do not load ammonium nitr ate and fuel oil in the controlled blast holes. Use exp losives and blasting accessorie s appropriate for the conditions of the blast hole (i ncluding water in the holes) and necessary to achieve satisfactory results; 12. Assemble and affix continuous column cartridge-type explosi ves to the detonating cord in accordance with the expl osive manufacturer's instructio ns; 13. The bottom charge in a blast hole may be larger than the ch arges above, but not large enough to cause overbreak. Place the top charge far enou gh below the collar and sufficiently reduced in size to avoid overbreaking or heavi ng; and 14. Use a dry, angular, and granular Material that passes a 3/8 inch sieve to stem the controlled blast holes, from the top charge to the hole collar.

203.3.3 1.7.4 Pre-Split Blasting

The Contractor shall perform pre-split blasting in accordance with Section 203.3.3.1.7.3, “Controlled Blasting Requirements,” and the following requireme nts: 1. Detonate the pre-split blast holes before drilling for produ ction blasting; or fire the pre-split blast holes at least 75 Ms before the production hole s if detonated in the same blast; 2. Fire pre-split blast holes simultaneously, unless ground vib rations, noise, or air blast are excessive. Fire pre-split holes in delayed sections and re duce the charge weight per delay to mitigate excessive effects; Section 203: Excavation, Borrow, and Embankment Page 107 3. The line of pre-split blast holes will extend beyond the lim its of the production blast holes to be detonated. The minimum length of this extension wi ll be 30 Ft or to the end of the cut, but will not be greater than one-half of the di stance of the expected blast advance; and 4. Do not perform pre-split blasting if the distance between th e controlled blast line and free face is less than 20 Ft or less than three (3) times the b last hole depth, whichever is greater.

203.3.3 1.7.5 Cushion Blasting

The Contractor shall perform cushion blasting in accordance wi th item No. 3 of Section

203.3.3 1.7.3, “Controlled Blasting Requirements,” and the foll owing requirements:

1. Perform cushion blasting as part of the final shot after oth er blasting is finished; 2. If the final shot includes p roduction blast holes, detonate the cushion blast no more than 75 Ms or less than 25 Ms a fter the production blast; and 3. Fire cushion blast holes simultaneously, unless ground vibra tions, noise, or air blast are excessive. Fire cushion bl ast holes in delayed sections an d reduce the charge weight per delay to mitigate excessive effects.

203.3.3 1.7.6 Production Blasting

The Contractor shall perform production blasting in accordance with the Blasting Plan that produced Acceptable results in blasting test sections and the following requirements: 1. Minimize blast damage to the final excavation backslope; 2. Drill buffer rows of production blast holes on a plane appro ximately parallel to the controlled blast line; 3. Place the buffer row of produc tion blast holes no closer tha n six (6) Ft to the controlled blast line unless the Contractor can prove the final excavation backslope will not be damaged by the production blast; 4. Where necessary to minimize damage to the excavation backslo pe, load blast holes in the buffer row lighter than other production holes; 5. Ensure the bottoms of producti on blast holes are not lower t han the bottom of controlled blast holes, exc ept in the lowest lift; 6. Ensure the diameter of produc tion blast holes does not excee d six (6) inches, unless approved by the Project Manager; 7. Before placing charges, ensur e the hole is free of obstructi ons. Use casing, if necessary, to prevent the walls o f the hole from collapsing; 8. Use a dry, angular, and granular Material that passes a 3/8 inch sieve to stem the holes, from the top charge to the hole collar; 9. Detonate production blast hol es in a controlled delay sequen ce toward a free face; 10. Do not use horizontal holes for production blasting, except for Equipment access; and 11. Use explosives and blasting accessories appropriate for wet or dry blast hole conditions as necessary to achi eve satisfactory results.

203.3.3 1.7.7 Scaling and Stabilization of Slopes Established b y Controlled Blasting

The Contractor shall perform scaling and stabilization of slop es established by controlled blasting in accordance with the following requirements: Section 203: Excavation, Borrow, and Embankment Page 108 1. Observe the entire blast area following a blast before start ing Work in the cut. If any rocks are loose, hanging, or potentially dangerous within a bla s t a r e a , t h e Contractor shall remove them. Scale slopes by hand using a sta ndard steel mine scaling rod. Use other methods to supplement or in lieu of han d scaling, such as, machine scaling, hydraulic splitters, or light blasting, if app roved by the Project Manager; 2. Slopes shall be scaled and stabilized before further constru ction activities take place. Scale slopes throughout the span of the Contract and as often as necessary to keep the slopes free of hazar dous loose rock or overhangs; a nd 3. Cease blasting operations if t he following conditions exist: 3.1. There is an excessive amount of breakage beyond the specif ied lines and grade; 3.2. There is excessive flyrock; 3.3. The final backslope within t he specified tolerances is not uniform; 3.4. Ground vibration and air bl ast levels exceed limits specif ied in Section 617, “Vibration Monitoring and Video Taping;” 3.5. There are violations of other requirements of the Specific ations; 3.6. The slopes are unstable; 3.7. The safety of the public is jeopardized; and 3.8. Property or natural features are endangered.

203.3.4 Borrow

The Contractor shall be responsible for obtaining the borrow s ource, unless otherwise specified in the Contract. The Contractor shall exhaust all av ailable suitable Material from unclassified excavation operations prior to utilizing a borrow source. The Contractor shall notify the Project Manager in writing, and request that borrow operations commence, when the Contractor exhaust unclassified excavation Material for Embankm ent. Borrow placed prior to this notification shall not be paid. If the Contractor places more than the specified amount of borrow and causes a waste of uncl assified excavation, the Depar tment will deduct the wasted amount from the borrow volume, as measured in the borrow area. After unclassified excavation is complete, the Contractor shall blade the areas th at require borrow to allow accurate payment measurements by cross sectioning by the Contra ctor. The Contractor shall maintain and restore Right of Way fencing removed for borrow op erations to its original condition or better to prevent livestock from entering Right of Way during the Project.

203.3.5 Embankments

The Contractor shall not place Embankment Material on frozen e arth, or incorporate frozen soils in Embankments. The Contractor shall suspend Emba nkment construction if Embankment Materials become frozen. The Contractor shall not r esume until the Materials are thawed and suitable for compaction. Before beginning Emban kment construction, the Contractor shall perform scalping in accordance with Section 20 1, “Clearing and Grubbing.” The Contractor shall bench new Embankments into the following: 1. Natural slopes including rock; 2. Existing Embankments; or 3. Phased Embankment construction. The Contractor shall ensure benches are wide enough to allow o peration and placement of compacting Equipment. The Contractor shall recompact new Em bankment Material and Section 203: Excavation, Borrow, and Embankment Page 109 Material that is cut out at no additional cost to the Departmen t. The Contractor shall not place rock, broken concrete, or other solid Materials in Embankment a reas where driven pilings, drilled shafts, utility lines, or other Structures are specifie d in the Contract.

203.3.5 1 Roadbed Embankments

The Contractor shall break up the original ground surface to a t least six (6) inches by plowing, scarifying, or stepping up. The Contractor shall comp act this area in accordance with Section 203.3.6, “Moisture and Density Control.” The Contracto r shall place Material for Roadbed Embankment in uniform lifts not exceeding eight (8) inc hes thick and compact in accordance with Section 203.3.6, “Moisture and Density Control. ” The Department will allow rocks no larger than three (3) Ft (i n any dimension) as long as the Contractor distributes and f ills the interstices to form a dense mass. If the interstices between the rock fragments cannot be completely filled and comp acted, the Contractor shall use bridging geotextile, approved by the Project Manager, over the top of the rock fragments to prevent the overlying Embank ment Material from filling the i nterstices. The Contractor shall not use rock fragments that may degrade with time or may be wat er sensitive (such as shale or gypsum) as rock fill in Roadbed Embankments. The Contractor may place larger rocks greater than three (3) F t in any dimension in the toe of the slope in accordance with the following requirements: 1. No rock is larger than one-half the Embankment height or ten (10) Ft; 2. No rock is placed in fill height less than eight (8) Ft, mea sured at the edge of the Roadway Shoulder; and 3. Place rocks inside a line six (6) inches from the slope stak e, space a minimum of three (3) Ft from edge to edge, and cover with approved Embankm ent Material. The Contractor shall construct rock Embankments to a maximum o f six (6) inches below Subgrade elevation. The Contractor shall consolidate rock fill s by using the appropriate Equipment and methods approved by the Project Manager.

203.3.5 2 Non-Roadbed Embankment

203.3.6 Moisture and Density Control

Maximum dry density of all soil types encountered or used will be determined in accordance with AASHTO T 180 (Modified Proctor), Method A or D (TTCP Modified). The Contractor shall construct Roadbed, Roadbed Embankment, no n-roadbed Embankment, and Roadway Median excavation or Embankment, with m oisture and density control. The Contractor shall compact each layer of Embankment to at least 95% of maximum density as specified above. The Contractor shall ensure that t he in-place moisture content of the soil shall not be less than five percent (5%) below optimum moisture content or greater Section 203: Excavation, Borrow, and Embankment Page 110 than two percent (2%) above optimum moisture content, at the ti me of compaction. For soils with a plasticity index of 15 or greater, the Contractor shall ensure the moisture content of the soil at the time of compaction is between optimum moisture to o ptimum moisture plus four percent (4%). If the moisture content at the time of compactio n is not within the specified range, the Contractor shall moisten or dry the Material, then t horoughly mix the Material to the full lift depth before re-compac ting. No additional payment sh all be made for the reworking of Materials that do not fall with in the ranges specified above. Roadbed Embankments that contain mostly rock or coarse-grained Material (65% or greater retained on the No. 4 sieve) do not require moisture an d density control, except the top six (6) inches of the Embankment ; the Contractor shall construc t in accordance with Section 207.3, “Construction Requirements.” Non-roadbed Embankments of rock Material will not require moisture and density control unless otherwise specified in the Contract. The Department will perform field densities in accordance with AASHTO T 310 or other Department approved methods. Dens ities shall be measured at ea ch lift before the next subsequent lift is placed in accor dance with Section 906, “Mini mum Testing Requirements.”

203.4 Method of Measurement

203.4.1 Rock Excavation

The Department will measure Rock Excavation based on the estim ated percentages if shown in the Contract, unless otherwise requested by the Contra ctor and approved by the Department. If the Contractor requests, the Department will measure Rock E xcavation in its original position for Material classifi ed as Rock Excavation in accordan ce with Section 203.2.1.1, “Rock Excavation.” Before excavation, the Contractor and Proje ct Manager must agree on the limits of Material classified as rock excavation. The Contract or shall calculate volumes in accordance with Section 203.4.3, “Unclassified Excavation and B orrow.” The Contractor shall include in measurements the overbreakage in rock excavation a m aximum of ten (10) inches beyond the backslope specified in the Plans or as directed by t he Project Manager. The Department will use the blaster’s drill-hole log cards to deter mine the quantities of rock excavation covered by soil or overburden. The Contractor shall provide these log cards as part of the surveying records. The Department will pay for stab ilization necessitated by exis ting geological conditions and for Base Course and geotextile if necessary as required to backfill rock Subgrade conditions.

203.4.2 Controlled Blasting

The Department will measure Cont rolled Blasting by the blast h oles drilled along the final line, whether loaded or not; and will measure the lengths from the top of the rock surface to the elevation of the Roadway di tch or to a bench elevation set by the Project Manager. The Department based the quantities for Controlled Blasting shown i n the Plans on assumed blast hole spacing; the actual quant ities depend on field conditions and the results from test sections.

203.4.3 Unclassified Excavation and Borrow

For each phase of the Project, identified in the Contract or a pproved by the Department, the Contractor shall measure the original ground surface of all areas that are designated as unclassified excavation (cut sec tions) and/or Embankment (fill sections using available Section 203: Excavation, Borrow, and Embankment Page 111 unclassified excavation Material), or Borrow (fill sections whe n all unclassified excavation Material has been exhausted). P rior to any Work continuing in completed excavation areas, the Contractor shall measure the newly excavated ground surface ( f i n a l s u r f a c e ) . F o r Embankment and borrow areas the Contractor shall measure the fi nal surface once these operations are completed and Accepted by the Project Manager. Prior to commencing Borrow operations the Contractor must ensure that all requirements of Section 203.2.1.3, “Borrow” have been met. Earthwork quantities will be calculated as the neat volume from the original ground surface (less the existing Roadway surfacing) between th e limits shown on the plans, and/or authorized changes by the Project Manager, and the new g round surface. The Department will not apply any shrinkage or swell factor due to payment being made on the final cross sectioned volume. For the measurements described above the Contractor shall surv ey and submit the original ground surface and final surface data at completion of each phase of construction using an electronic XML- compatible format approved by the Proj ect Manager. The Contractor shall use a New Mexico licensed Engineer or New Mexico licensed surveyor to stamp and certify cross-sections at 50 Ft intervals, unless otherwise spe cified in the Contract or approved by the Project Manager prior to commencement of earthwork opera tions. The Contractor shall submit certified volume summary reports to the Project Manager based on this electronic data for each phase of construction in cluding a report that summariz es the basis for the final volumes.

203.5 Basis of Payment

Pay Item Pay Unit Rock Excavation Cubic Yard Unclassified Excavation Cubic Yard Borrow Cubic Yard Unsuitable Material Excavation Cubic Yard Controlled Blasting Linear Foot

203.5.1 Double Handling

The Department will pay for excavated Materials that require m ore than one (1) handling as identified within the Contract before final placement, inclu ding fertile topsoil required to be stockpiled and reserved for later use in the Work: 1. At the Bid Item Unit Price for unclassified excavation, for each handling approved by the Project Manager; or 2. As another item of Work for the second handling if specified in the Contract. However, if the Contractor handles excavated and borrow Materi als more than once, at the Contractor’s request or at the convenience of the Contracto r, there will be no additional cost to the Department. If the Contractor chooses to stockpile excess unclassified excavation Material to be used as borrow in a later phase, the Department will not pay for this Material as double handling. Double handling shall not be paid for Materia l that is excavated and placed in the same phase of the Project.

203.5.2 Work Included in Payment

The Department will consider the item(s) listed in this sectio n as included in the pay items(s) listed in Section 203.5, “Basis of Payment” and will n ot measure or pay for them separately: Section 203: Excavation, Borrow, and Embankment Page 112 1. Controlled blasting drill holes through overburden; 2. Production blasting; 3. Scaling within the limits of a final backslope established b y controlled blasting; 4. Damage resulting from blasting; 5. Mobilization of any Equipment and testing of rock in accorda nce with Section

203.2.1 1, “Rock Excavation;”

6. Time Delays to perform testing of rock in accordance with Se ction 203.2.1.1, “Rock Excavation;” 7. Material required to fill the voids and irregularities in Em bankment areas below the tolerance limit from the specified elevation; 8. Bridging geotextiles required to prevent overlying Embankmen t Material from migrating into the interstices between rock fragments; 9. Fence removal and replacement; 10. AASHTO T-190 Resistance R-Va lue and Expansion Pressure of C ompacted Soils, including sampling, laboratory testing and reporting; 11. AASHTO T-290 Water-Soluble Sulfate Ion Content in Soil, inc luding sampling, laboratory testing, and reporting; 12. Survey, calculations, and engineering; 13. Hauling and/or disposal related to Rock Excavation, Unclass ified Excavation, Borrow, and Unsuitable Material Excavation; and 14. Suitable backfill Material for Unsuitable Material Excavati on. The Contractor shall dispose of Material in accordance with Se ction 107, “Legal Relations, Environmental Requirements, and Responsibility to th e Public” unless otherwise specified in the Contract. The Contractor shall not dispose of Material within t he Project Limits without written approval from the Project Manager. Section 203-A: Unstable Subgrade Stabilization Page 113 SECTION 203-A: UNSTABLE SUBGRADE STABILIZATION 203-A.1 DESCRIPTION This Work consists of stabilizi ng unstable Subgrade soils enco untered in non-borrow sections such as cuts or exist ing grades within and not exceedi ng the top two (2) feet of finished sugbrade elevation due to no fault or neglect of the C ontractor. This Work includes costs associated with design/development of the Contractor’s pr oposed stabilization option, Materials, labor, tools, Equipment, storage, laboratory and fie ld testing, sampling, handling, excavation, disposal, removal, placement, hauling, processing w ith the Subgrade, shaping, compacting, surveying, finishing to grade, proof-rolling the Su bgrade including all appurtenances, and Incidentals nece ssary to complete the Work. Unstable Subgrade is defined as Subgrade that is saturated, so ft, gummy, pumping, and/or displaces with applied loading. Subgrade modified by this Specific ation is for stabilization o nly and is not considered in the structural design of the pavement structure; thus, no modif ication of the pavement structure shall be made. 203-A.2 MATERIALS The Contractor shall use Materials included on the Department’ s current approved products list for its intended use or use Materials currently A ccepted in the Contract. 203-A.3 CONSTRUCTION REQUIREMENTS Where unstable Subgrade is due to the failure of the Contracto r to maintain adequate surface drainage, or is damaged due to the operations or any ot her fault or neglect of the Contractor, the unstable condition shall be corrected at no exp ense to the Department. Prior to Base Course placement over Subgrade or proposed stabi lization option, the Contractor shall proof roll the Subgrade with either a pneumati c roller weighing a minimum of 25 tons or a 4000 gallon water truck filled to capacity. Areas lacking sufficient stability, as defined above, or as directed by the Project Manager shall be t reated as unstable Subgrade. Areas that exhibit displacement under lightly loaded Equipment may also be considered unstable by the Project Manager. For areas that become unstabl e prior to reaching Subgrade level (i.e., foundations, intermediate lifts, etc.), the Projec t Manager may designate these areas as unstable. The Contractor shall choose any of the stabilization options l isted below unless otherwise indicated in the Contract. If site conditions warrant a change in the stabilization method, it shall be at no additional cost to the Department. The Contract or shall submit options to the Project Manager for concurrence prior to stabilization. 1. Ripping, drying, and recompacting; 2. Excavation and replacement wit h Material that meets or excee ds the Project design R-value with laboratory tests performed in accordance with AASH TO T-190; 3. Use of Base Course, RAP, or select backfill; 4. Installation of underdrains and associated geotextiles and M aterial; 5. Geotextiles, geogrid base, and/or reinforcement Materials; 6. Blending of existing Materials with Materials approved by Pr oject Manager; or Section 203-A: Unstable Subgrade Stabilization Page 114 7. Combinations thereof. The Project Manager may approve the use of excess Material obt ained within the ROW that has previously been shown to be stable and workable. The Material associated with the listed options and the Work invol ved to obtain and place the Ma terial shall be Incidental to the “unstable Subgrade stabilization” item and will not be paid sep arately. Areas disturbed within the ROW but not designated in the Contract shall be revegetated in accordance with Section 632, “Revegetation” at the Contractor’s expense. After stabilization and prior to placement of the base Materia l, the Contractor shall proof roll the stabilized Subgrade with either a pneumatic roller wei ghing a minimum of 25 tons or a 4000 gallon water tank filled to capacity and the Subgrade shal l exhibit no displacement when proof rolled. The Contractor shall make the necessary adjustments in the Equ ipment or operation so that underground utilities and permanent structures are not dam aged. The Contractor shall handle the processing of Material in such a manner that the dust or debris created by the operation will not be hazardous to the pu blic or workers. The Contractor shall construct stabilized Subgrade in such a m anner that proper drainage is maintained. When within the top six (6) inches of the Subgrade elevation, the stabilized Subgrade shall meet the grade and compaction requirements of SECTION 207 , “SUBGRADE PREPARATION,” or as approved by the Project Manager. Additiona l payment will not be made under Item Number 207000 – “Subgrade Preparation.” 203-A.3.1 Equipment Stabilization of unstable Subgrade shall be performed with a m achine or combination of machines or Equipment that will produce a satisfactory product meeting the requirements for ripping, drying, recompaction, e xcavation, replacement, and ble nding of Materials as provided in these Specifications. Single-shaft or multiple-shaft mixers are required for blendin g of existing Materials with Materials approved by Project Manager. Agricultural disks or m otor graders are not Acceptable mixing Equipment unle ss Contractor can demonstrate t horough mixing and processing to the satisfaction of the Project Manager. 203-A.3.2 Acceptance The stabilized Subgrade shall meet the requirements of SECTION 303, “BASE COURSE;” subsection 303.3.1, “Preparation of Subgrade.” Prior to placement of the base Material, the stabilized Subgrade shall be proof rolled with ei ther a pneumatic roller weighing a minimum of 25 tons or a 4000 gallon water tank filled to capaci ty and shall exhibit no displacement when proof rolled. Stabilized Subgrade locations that continue to exhibit displacement are to be corrected at no additional cost to the D epartment. 203-A.4 METHOD OF MEASUREMENT Unstable Subgrade stabilization shall be measured from the Sub grade elevation as shown in the Contract, by the square yard regardless of depth u p to two (2) feet. 203-A.5 BASIS OF PAYMENT The Department will only pay for the Accepted quantities of un stable Subgrade stabilization in accordance with Section 203A.3.2, “Acceptance. ” Pay Item Pay Unit Unstable Subgrade Stabilization Square Yard 203-A.5.1 Work Included in Payment The Department will consider the item(s) listed in this sectio n as included in the pay items(s) listed in Section 203-A.5, “Basis of Payment” and will not measure or pay for them separately: 1. Design/Development of Contract or proposed stabilization opti on(s); 2. All Materials required for stabilization; 3. Labor, tools, and Equipment; 4. Sampling and laboratory and field testing; 5. Handling, excavating, removi ng, disposing, hauling, and plac ement; 6. Processing Material with existing Subgrade; 7. Shaping, compacting, surveying, finishing to grade, proof-ro lling, and all appurtenances and Incidentals necessary to complete the Work; 8. Subgrade Preparation; and 9. Revegetation of areas disturbed within the ROW, used to obta in Materials for stabilization. Section 206: Excavation and Backfill for Culverts and Minor St ructures Page 116

Source: New Mexico Standard Specifications for Highway and Bridge Construction, 2019 Edition. Pages 0–0 of 974.

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201 Clearing And Grubbing

206 Excavation and Backfill for Culverts and Minor Structures