203Excavation and Embankment

203.01.01 General. This work consists of excavating material , constructing embankments , and placing

engineering fabrics . This includes furnishing, hauling, stockpiling, placing, disposing, sloping, shaping, compacting, and finishing earthen and rocky material. Perform work in close conformity with the alignment, grades, and cross sections shown on the plans or as established. MATERIALS

203.02.01 General. Material shall conform to the following Subs ections and Section :

Borrow ................................ ................................ ................................ ................................ ................................ .... Subsection 704.03.12 Selected Borrow ................................ ................................ ................................ ................................ ...................... Subsection 704.03.13 Engineering Fabrics ................................ ................................ ................................ ................................ ............................... Section 731

203.02.02 Roadway Excavation. Roadway excavation consists of all excavation involved in grading and

constructing the roadway and a ppurtenances, irrespective of the nature or type of material encountered. Exceptions are excavation designated as structure excavation, drainage excavation, and channel excavation when these items are provided as items of work under the contract. Dividing the project into construction stages shall not be construed as separate material classification.

203.02.03 Drainage Excavation. Drainage excavation includes all excavation in the construction of open

ditches less than 3.6 m (12 ft) in bottom width, except ditches that are part of the roadway prism as shown on the plans. The nature or type of material encountered shall have no bearing on the classification of material.

203.02.04 Channel Excavation. Channel excavation includes all excavation in the construction of open

ditches with a bottom width of 3.6 m (12 ft) or more with the exception of ditches that are part of the roadway prism as shown on the plans. The nature or type of material encountered shall have no bearing on the classification of mate rial.

203.02.05 Borrow. Borrow consists of approved material required for the construction of embankments .

Material obtained from excavation items is considered excavation only and not borrow. Borrow will not be classified according to type or character o f material encountered in the borrow area unless otherwise required in the Special Provisions. Do not use pea gravel as borrow. Pea gravel is typically a byproduct of aggregate crushing and/or screening operations. It is uniformly graded, normally having a nominal size of 9.5 mm (3/8 in.) .

203.02.06 Selected Borrow. Selected borrow consists of approved material required for the construction of

embankments. Do not use pea gravel as selected borrow. Pea gravel is typically a byproduct of aggregate crushing and/or screening operations. It is uniformly graded, normally having a nominal size of 9.5 mm (3/8 in.). CONSTRUCTION

203.03.01 Roadway. Excavate to lines and grades as staked. Avoid removing or loosening any material

outside the required slopes. Replac e and compact any disturbed material to the required cross section. Grade intersecting roads, approaches, and driveways as shown in the plans or as directed. Begin at some definite point or points on the project, and carry forward in an approximately com pleted manner. Grade the roadway to full cross section width before placing base or surfacing of any type, unless otherwise specified. Incorporate only suitable material into embankments. Dispose of unsuitable material. 203 EXCAVATION AND EMBANKMENT 90 203.03.02 Unsuitable Material. Unsuitable material shall be defined as mixtures of soils, organic matter or other material not suitable for embankment material regardless of moisture content. Excavate and dispose of unsuitable material, including material below the natural ground surface in embankment areas as directed. Fill any resulting subexcavation with material suitable for the planned use. Place and compact such suitable material in layers as hereinafter specified under embankment. Dispose of material outside the right of way accor ding to Subsection 107.14.

203.03.03 Blasting. Remove any material outside the authorized cross section on the backslopes which may

be shattered or loosened because of blasting. Compact or remove shattered or loosened material below the bottom limits of required excavation. Discontinue any method of blasting which leads to overshooting or is dangerous to the public or destru ctive to property or to natural features. See Subsection 107.10.

203.03.04 Rock Cuts. Do not break down, loosen, or otherwise damage supporting rock below the bottom

limits of the required excavation. Scale and dress the slope of all rock cuts to a safe, stable condition by removing all loose spalls and rock not firmly keyed to the rock slope. Remove overhanging rock which may be a hazard to public use of the roadway. Construct slopes in solid rock excavation to the approximate neat lines as staked. No r ock shall project or overhang more than 300 mm (12 in.) from the true slope.

203.03.05 Overbreak. Overbreak is that portion of material excavated, displaced or loosened outside and

beyond the slopes or grade as staked or reestablished, regardless of the c ause. Slides and slipouts as defined in Subsection 203.03.09, and that portion of rock subgrade as hereinafter set forth, shall not be considered overbreak. Remove all side slope overbreak and dispose of as surplus material according to Subsection 203.03.0 7. Rock removed to a maximum depth of 150 mm (6 in.) below subgrade will be measured for payment as described in Subsection 203.04.01 (b).

203.03.06 Slopes. Trim excavation and embankment slopes, except in solid rock, to the lines as staked.

Round the t op of cut slopes by excavating to blend the cut slopes with the adjacent natural terrain. Round the top of embankments. At the intersection of cuts and fills, adjust and warp slopes to blend into each other or into the natural ground surface without notice able break. Cut slopes will be staked for flattening and rounding in places where the material is other than solid rock. Rock formations such as shales, decomposed sandstone , and granite that can be readily excavated by means of hand tools, shall have th e slopes flattened and rounded the same as earth slopes. A layer of earth overlying a rock cut shall be rounded above the rock the same as earth slopes. Where the depth of cut or fill is insufficient to provide the full rounding required, proportionately adjust the distance for rounding. Slope rounding and warping shall also apply to drainage ditches. Adjust slope grading to protect standing timber, trees or other vegetation which should be preserved. Adjust by a gradual transition from the theoretical grading section required. Construct slopes with a degree of smoothness that can be normally obtained by hand shovel operations.

203.03.07 Surplus Material. Use surplus excavated material to widen embankments uniformly, or to flatten

slopes, or at other approved locations. Do not dispose of surplus material unless approved in writing. Consider the quantity of surplus material shown in the plans to be approximate only. Determine that there is sufficient material available for the completion of the embankments within the areas involved before disposing of any indicated surplus material. Replace any shortage of material caused by premature disposal of the indicated surplus material. Dispose of surplus material according to Subsection 107.14 after the requirements of this Subsection have been met. EXCAVATION AND EMBANKMENT 203 91 203.03.08 Selected Material. When specified in the contract documents, use suitable selected material encountered in excavation for finishing the top portion of the subgrade. Selected material shall be defin ed as material which is excavated and used for selective purposes. Haul selected material directly from excavation to its final position on the roadbed and compact. Such work will be paid for at the contract unit price for the excavation item involved. Se e Subsection 104.0 4. When the transporting of selected material directly from excavation to its final position is impractical, leave the selected material in place until it can be placed. No additional compensation will be made because of any such delayed excavation. If, however, the conditions are such that the undisturbed selected material will hamper ordinary grading operations or cause unnecessary movements of equipment, the removal and stockpiling of sufficient selected materials may be ordered in wri ting. Stockpile at approved locations. Place the stockpiled selected material in final position on the roadbed when approved. Measurement for payment of selected material stockpiled as above provided will be according to Subsection

203.04.01 (d).

203.03 09 Slides and Slipouts. Excavate and remove material outside the planned roadway or ditch slopes

which is unstable and constitutes potential slides in the opinion of the Engineer. Excavate and remove material from slides which has come into the roadway or ditch, and material which has slipped out of new or old embankments as directed. Excavate material to designated lines or slopes in an approved manner. Dispose of such material or, if approved, use such material in the construction of embankments. The ab ove provisions do not relieve the duty of maintaining all slopes. Erosion, regardless of amount or extent, caused by the action of the elements which results in damage to work or materials, shall in no case be considered a slide or slipout. Measurement fo r payment will be according to Subsection 203.04.01 (f).

203.03.10 Drainage. Maintain the roadbed so that it will be well drained at all times.

Construct V -type ditches to the cross section and dimensions on the plans by means of suitable equipment which will deposit all loose material on the downhill side. In going from cut to fill, cut the roadway ditches to the right or left before reaching the fill so as to avoid damage to embankments by erosion. Excavate the flat -bottom ditches indicated on the plans, or as staked, to the required cross section and grade. Use excavated materials, if approved, to construct roadway embankments or dikes or both to form a continuous diversion channel as staked. To avoid destruction of natural growth during construct ion of ditches, channels, or dikes, confine travel of equipment to the construction limits as nearly as practicable. Where ditches, channels , or dikes are nearly parallel to the roadway, do not locate turnarounds closer than 300 m (1,000 ft) apart. See Sub section 107.12. Fine grade channel bottoms only if paving is specified.

203.03.11 Borrow. In case designated borrow deposits fail to contain the necessary quantity of acceptable

material, give notification in writing. If there is not sufficient quantity of acceptable material, the Engineer may designate an alternate deposit in which to obtain the deficit. In borrow pits having undesirable material, including overburden, organic and deleterious substances, remove and waste or redistribute the material, in a satisfactory manner. Remove and dispose of all refuse. Do not obtain borrow until all other excavation items are complete to the extent necessary to determine the need for borrow. Give notification 10 days in advance of opening any borrow areas so tha t cross sections of the ground surface after stripping may be taken, and the borrow materials can be tested before being used. 203 EXCAVATION AND EMBANKMENT 92 Excavate borrow deposits to regular lines as staked to permit accurate measurement, if required. Make the depth of excavation th roughout the area of the borrow pits as uniform as practicable. Construct side slopes conforming to Subsection 104.0 5. Excavate borrow pits so that they will drain to the nearest natural outlet. Materials which are not satisfactory for use for the purpose s intended will be rejected at the pit and shall be disposed of in a satisfactory manner. Excess excavated material will not be measured for payment.

203.03.12 Foundation for Embankment. When embankment is to be placed and compacted on hillsides, or

against existing embankments, or when embankment is to be built half width at a time, continuously bench the slopes that are steeper than 1:4 (4:1) as the work is brought up in layers. Bench with sufficient width to permit operations of placing and compacting equipment. Begin each horizontal cut at the intersection of the original ground and the vertical sides of the previous cuts. Recompact material thus cut out along with the new embankment material. If the width of the approved bench excavation exceeds 2 m ( 6 ft), the excavated material in excess of 2 m (6 ft) will be measured and paid for as roadway excavation. Clear and grub foundations for embankment according to Section 201. Where less than 0.3 m (1 ft) of embankment is to be placed over an existing bituminous or concrete surface, remove such surface and incorporate in the embankment or otherwise dispose of as approved. Removal of existing bituminous or concrete surface will be paid for as roadway excavation unless the contract documents specifically call for payment under Section 202.

203.03.13 Embankment Material. Construct embankments with suitable materials, excavated as prescribed

and with any excess materials from other operations which are acceptable and suitable for use. Use materials free fr om objectionable material such as leaves, grass, roots, logs, stumps, brush, or other perishable material. When there is a choice of material and when practicable, make the excavation so that the best material will be placed in the uppermost layer of the embankment for at least 0.3 m (1 ft) in depth. Stockpiling and subsequently rehandling embankment materials is not required except as provided in Subsection 203.03.08. Do not place material in the embankment when either the material, foundation or the embankment on which it would be placed is frozen. Where embankments are to be made of material from rock cuts or other material which is unsuitable for finishing the roadbed, form the upper 150 mm (6 in.) of the roadbed with approved material.

203.03.14 Pl acing Embankment. For embankment or backfill deposited against structures, see Subsection

207.03 02.

Where structure abutments are placed on embankment, construct the embankment to subgrade elevation before excavating for the construction of the abutment. Where the abutment is supported on piles, construct the embankment to the elevation of the bottom of the footing. Where structures are located under a rock embankment, cover the structures with not less than 0.6 m (2 ft) of satisfactory soil or granular materials before the embankment is placed over the structure. Place in layers not exceeding 200 mm (8 in.) in thickness before compaction, except as hereinafter specified. Begin the construction of an embankment at the lowest point of the fill below the g rade. Spread individual layers evenly to uniform thickness throughout and parallel with the finished grade for the full width of the embankment, unless otherwise permitted. When native ground will not support the mass of heavy hauling and spreading equipm ent, choose equipment as will least disturb the soft foundation. For approval to allow an increase in the planned layer thickness of embankment material over soft ground, satisfactorily prove that the planned depth is inadequate to support light hauling v ehicles. Necessary use of lighter hauling vehicles or different methods of embankment construction other than originally contemplated shall not be the basis for a claim for extra compensation. EXCAVATION AND EMBANKMENT 203 93 When approved, construct the lower part of the fill on the soft foundation by dumping and spreading successive vehicle loads in a uniformly distributed layer of a thickness not greater than that necessary to support the vehicle while placing subsequent layers. Construct the remainder of the embankment in layers and co mpact as specified. When less than 70 % of embankment material passes the 19 mm ( 3/4 in.) sieve, the material shall be considered “Rock Embankment.” Spread such materials in a uniform horizontal layer over the full width of the embankment. Do not exceed a layer thickness of 4/3 times the vertical dimension of maximum size material larger than 200 mm (8 in.). The largest size rock allowed in the embankment will be 1 m (3 ft) measured in vertical direction. Break up any larger rocks before placing in the emba nkment. Dispose of rock exceeding 1 m (3 ft) in an approved manner. In rock fills, do not directly end dump upon the previously constructed layer of embankment. Dump rock on the layer of embankment being constructed and doze ahead into place. Exercise care as much as practicable to work the fines and smaller rock into the spaces between the larger rock. Compaction will be required as provided in Subsection 203.03.16. To the extent of project requirements for embankment, use all rock from excavation for embankment. Plan the grading operation to use rock which may be encount ered in excavation according to the following provisions: Place rock so as to form the base of embankments or in the side slopes. Do not place rock in embankments where piles will be driven. When rock and other embankment materials are excavated at appr oximately the same time, distribute the rock throughout the fill and do not nest in one location. When there is insufficient material other than rock in the excavation to permit properly compacted layers, place the rock for the full cross -section width wi th the larger rocks well distributed and the void spaces filled with the smaller rocks and fragments. At locations that are inaccessible to the roller, bring up the embankment in layers of the thickness specified and compact each layer with mechanical tam pers or by hand tamping.

203.03.15 Compaction, Embankment. Optimum moisture content of the various soils will be determined. Wet

or dry the material for each layer before compaction as required in order to bring its moisture content within the prescribed limits. Route and distribute the hauling and leveling equipment full width over each layer of the fill in such a manner as to uniformly distribute the compaction afforded thereby. In addition to hauling and leveling equipment, provide compaction equipment that is specifically designed and manufactured for the purpose of compacting embankments. Work compaction equipment continuously with the grading equipment. Compact the base of cuts, natural ground having less than 1.5 m (5 ft) of embankment, measured fr om the subgrade, and embankment material to not less than 90% of the maximum density as determined by Test Method No. Nev . T108 . The in -place density will be determined by Test Method No. Nev. T102 or T103. When natural ground material is encountered that cannot be compacted to the required density, compaction requirements will be determined. Compact all selected borrow and structure backfill placed within the limits of embankments shown on the plans to not less than 95% of the maximum density as determine d by Test Method No. Nev. T108 . The in-place density will be determined by Test Method No. Nev. T102 or T103. Recompaction to the specified density may be required before placement of any subsequent course.

203.03.16 Compaction, Rock Embankment. Test com paction of rock embankments by proof rolling. Obtain

and test compaction using construction methods and equipment as follows:

203.03.17 Maintenance of Embankment. Replace embankment material which may be lost or displaced as a

result of natural settlement of the ground or embankment with acceptable material. The quantity of material required will be paid for at the contract unit price bid for the type of materials u sed. Remove and replace with acceptable material, any embankment or portion thereof which has been constructed with unapproved material. Remove and replace portions of the embankment which may become unstable or displaced as the result of carelessness or negligence.

203.03.18 Geotextile. Grade the area to receive the geotextile to an even, smooth surface that is free of

cavities, large stones, or other debris capable of punc turing or tearing the material. Do not place the geotextile until the surface has been approved. Use equipment for installation that is recommended by the manufacturer and approved. Unroll and place the geotextile parallel to the direction of placement of overlying material. Place the geotextile in direct contact with the surface with out wrinkles or folds. Do not drive vehicles or construction equipment directly on the geotextile. Do not damage the geotextile during the installation process. Avoid smearing the geotextile with mud or contaminating it with other foreign substances. Plac e the geotextile so that backfilling operations do not cause tearing or excessive stretching. Join adjacent sheets and roll ends together by overlapping or sewing. EXCAVATION AND EMBANKMENT 203 95 If adjacent sheets and roll ends are overlapped, then overlap upslope sheets over downslo pe sheets. Overlap roll ends and adjacent sheets a minimum of 0.3 m (1 ft). Maintain a minimum offset of 1.5 m (5 ft) between adjacent overlapped or sewn roll ends. If adjacent sheets and roll ends are sewn, use a polypropylene or polyester thread with a color contrasting to the geotextile. Submit a seam assembly description including seam type, stitch type, sewing thread, and stitch density along with seam samples. Provide a certificate of compliance to verify that the seam strength meets a minimum of 90% of the required grab strength of the geotextile. Limit atmospheric exposure of the uncovered geotextile to 10 days to minimize damage potential due to sunlight, rain, dirt, and contamination. Do not cover the geotextile until it has been confirmed that no holes, tears, folds, wrinkles, or contaminated areas exist. Repair holes or tears by placing a new layer of geotextile over the defect that extends beyond the defect edges at least 0.3 m (1 ft) in all directions. Remove and replace contaminated areas w ith new geotextile. Place overlying material by dumping from the edge of the geotextile, or from previously placed lifts. Place a minimum thickness of 200 mm (8 in.) of overlying material on top of the geotextile before operating vehicles or construction equipment thereon. Do not turn construction vehicles on the first lift of material placed on top of the geotextile. If damage occurs to the geotextile from construction equipment or pumping of the subgrade, use small and lightweight equipment to reduce th e weight on the geotextile. If rutting or bumps occur after the geotextile is placed, do not blade off the high spots. METHOD OF MEASUREMENT

203.04.01 Measurement. Excavation will be measured on a volume basis by cross sectioning the area to be

excavated and computing neat lines for an end area. The average end area method will be used with no allowance made for curvature. If it is impossible or impractical to measure quantities by average end areas, the quantities will be computed by a method which is be st suited to obtain an accurate determination. Excavation will be measured by the cubic meter (cubic yard) of material excavated and placed as required. The estimated quantities shown on the plans, plus or minus authorized quantity changes, will be the qu antity used for payment. The Engineer or the Contractor may, however, request a final measurement, in which case final cross sections will be taken. Submit request for final measurement in writing. When final cross sections are taken the determination of q uantities derived therefrom will be the quantities used for payment. If the Contractor requests final measurement and the quantities thus determined are equal to or less than the planned quantities plus authorized changes, the Contractor shall reimburse th e Department for the Department’s expenses incurred by such final measurement. When changes are made during construction such as widening cuts, changing grades, disposing of unsuitable material, stockpiling selected material and other changes resulting in increases or decreases in quantities, then additional measurements for payment will be made as hereinafter outlined:

203.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract

price per unit of measurement for the pay items listed below that are shown in the proposal. Payment will be considered full compensa tion for the work prescribed in this Section. Payment will be made under: Pay Item Pay Unit Roadway Excavation ................................ ................................ ................................ ................................ ......... Cubic Meter (Cubic Yard) Drainage Excavation ................................ ................................ ................................ ................................ ......... Cubic Meter (Cubic Yard) Channel Excavation ................................ ................................ ................................ ................................ .......... Cubic Meter (Cubic Yard) Borrow Embankment ................................ ................................ ................................ ................................ ......... Cubic Meter (Cubic Yard) Borrow Excavation ................................ ................................ ................................ ................................ ............ Cubic Meter (Cubic Yard) Selected Borrow Embankment ................................ ................................ ................................ .......................... Cubic Meter (Cubic Yard) V-type Ditches ................................ ................................ ................................ ................................ ......................... Linear Meter (Station) Geotextile (class) ................................ ................................ ................................ ................................ ......... Square Meter (Square Yard) Geogrid ................................ ................................ ................................ ................................ ........................ Square Meter (Square Yard) Geomemb rane ................................ ................................ ................................ ................................ ............. Square Meter (Square Yard) 99 SECTION 206 STRUCTURE EXCAVATION DESCRIPTION

206.01.01 General. This work consists of the removal of material encountered for the construction of selected

structures and other excavation specifically designated as structure excavation. This work also includes the work of disposing of surplus material and cleaning up the sites. Structure excavation includes dewatering and the construction or installation of all cofferdams, cribs, shoring, and other facilities which may be necessary to perform the excavations and the subsequent removal of such facilities except where they are required or permitted to remain in place. It also includes the necessary clearing and grubbing within the proposed structure area and removing old structures or parts thereof as required if the proposal does not include separate bid items for such work. For specific requirements pertaining to the excavation involved in the installation of pipe culverts and underground piping, attention is directed to those Sections of these specifications governing such work. Design and construct shoring, cribbing, or cofferdams as required. Construct safe and adequate shoring, cribbing, or cofferdams to provide the necessary rigidity and support the loads imposed. Submit 6 sets of design calculations along with detailed drawings of the shoring, cribbing, or cofferdams for approval according to Subsection 105.02. Such design calculations and drawings shall be prepared and stamped by a professional engineer registered as a Civil Engineer in the State of Nevada. If such plans are not satisfactory make such changes in them as may be required. Do not begin construction of such shoring, cribbing, or cofferdams until the drawings are approved. Allow 30 days for Department review and approval of complete excavation shoring shop drawings. Allow an additional 60 days for such shop drawings that also require Railroad approval. Do not begin excavation shoring construction until shop drawings have been approved. No additional time will be provided for shop drawings submittals that are returned for correction by either the Department or the Railroad. Follow OSHA safety regulations (29 CFR, Part 1926, Subpart P, Excavations) for sloping the sides of excavations, using shoring and bracing, and for using other safety features. When sides of excavations are sloped for safety considerations submit, for informational purposes, one copy of the design that demonstrates conformity with OSHA regulations. Where support systems, shield systems, or other protective systems are to be used, submit design calculations along with detailed drawings that demonstrate conformity with OSHA regulations. Submit the design calculations and detailed drawings according to Subsection 105.02.

206.01.02 Classification. Classification of structure excavation will not be made on the basis of materials or

conditions encountered. Classification of excavation, if made, will be on the basis of the material removed between certain elevations, and such classification as shown on the plans or set forth in the Special Provisions shall not be changed regardless of the material encountered. CONSTRUCTION

206.03.01 General. Give notification at least 2 weeks in advance of the beginning of excavation so that

elevations and measurements may be taken of the existing ground before it is disturbed and of existing substructure units within the limits of excavation for structures before they are removed. Material excavated or removed before these measurements have been taken will not be paid for. Excavate to the established elevations and dimensions. Consider the elevation of the bottoms of footings as shown on the plans as approximate only. Changes in dimensions or elevation of footings as may be necessary to secure a satisfactory foundation may be ordered in writing. Compact culvert pipe and structure foundations to not less than 90% of the maximum density as determined by Test Method No. Nev. T108. The in-place density will be determined by Test Method No. Nev. T102 or T103. Cut rock or other hard foundation material to a firm surface, either level, stepped, or serrated. Clean the excavation of loose material. Clean out and fill seams and crevices with concrete mortar or grout. Should foundation excavation be below grade, backfill to the required elevation with backfill or foundation fill with no additional payment.