New Mexico CID GS-8 Earthmoving, Excavation and Ditching Examination

When converting an excavated volume from cubic feet to cubic yards, what divisor must be used?

• A9
• B12
• C27
• D36

On a civil plan, station 8+50 is how many feet from station 0+00?

• A8.50 feet
• B85 feet
• C850 feet
• D8,500 feet

On grade stakes used for earthmoving, what does a cut (C) mark indicate relative to the reference elevation?

• AThe finished grade is higher than the existing ground
• BThe finished grade is lower than the existing ground, so material must be excavated
• CThe stake marks a property corner only
• DThe soil has already been compacted to specification

A rectangular excavation is 60 feet long, 20 feet wide, and 4 feet 6 inches deep. What is the bank volume in cubic yards?

• A200 cubic yards
• B540 cubic yards
• C74 cubic yards
• D5,400 cubic yards

A contractor must excavate 800 bank cubic yards (BCY) of soil that swells 25 percent when loaded. How many loose cubic yards (LCY) will the trucks haul?

• A640 LCY
• B800 LCY
• C1,000 LCY
• D1,600 LCY

In earthwork estimating, what does the load factor do?

• AConverts compacted cubic yards to loose cubic yards
• BConverts loose cubic yards to bank cubic yards
• CConverts stationing to contour interval
• DConverts slope ratio to degrees

A ditch invert drops 6 feet over a 50-foot run. What is the slope expressed as a percent?

• A6 percent
• B8 percent
• C12 percent
• D50 percent

On a topographic plan, what do closely spaced contour lines indicate?

• AA flat area with little grade change
• BA steep slope
• CThe location of underground utilities
• DThe compaction specification

Using the average-end-area method, two successive cross sections 90 feet apart have end areas of 48 square feet and 60 square feet. What is the volume between them?

• A180 cubic yards
• B108 cubic yards
• C4,860 cubic yards
• D54 cubic yards

A fill requires 3,000 compacted cubic yards (CCY). The borrow soil shrinks 15 percent from bank to compacted state. How many bank cubic yards (BCY) must be excavated?

• A2,550 BCY
• B3,000 BCY
• C3,450 BCY
• DAbout 3,529 BCY

Which machine is the primary production tool for digging a utility trench and placing pipe bedding from one setup?

• AMotor grader
• BHydraulic excavator or backhoe
• CSmooth-drum vibratory roller
• DSelf-loading scraper

Which machine is used to cut final grade, shape drainage swales, and blade a site to the design surface?

• ASheepsfoot roller
• BTrack excavator
• CMotor grader
• DPile driver

For moving large volumes of earth over longer haul distances on an open cut-and-fill job, which machine is typically most efficient?

• AWalk-behind plate compactor
• BSelf-propelled scraper
• CHand shovel
• DJumping-jack rammer

A crawler dozer is generally the most efficient production choice for which earthmoving task?

• APushing soil a short distance and spreading it
• BHauling spoil 3 miles to an off-site dump
• CFinish-blading a parking lot to ±0.02 foot
• DDriving steel sheet piles

On a long dozer push, which blade type holds the largest load with the least spill?

• AStraight blade (S-blade)
• BU-shaped blade (U-blade)
• CAngle blade set fully left
• DNo blade; use the ripper only

What is the purpose of slot dozing?

• ATo compact the lift with the tracks only
• BTo reduce load loss by pushing in a trench formed by previous passes
• CTo sidecast material off a slope
• DTo finish-blade a paved surface

The main production advantage of an angle blade compared with a straight blade is the ability to:

• ACarry a larger load on a long push
• BSidecast material to one side while traveling forward
• CRip solid granite
• DCompact clay to modified Proctor density

A wheel trencher is generally a better production choice than a hydraulic excavator when the work is:

• AA long, uniform-width trench in stable soil without many crossings
• BA short, irregular basement excavation next to a building
• CRock that must be blasted
• DA wide mass excavation for a pond

According to typical pipe-and-excavation production analysis, a complete earthmoving cycle is made up of which four operations?

• ASurveying, permitting, paving, and striping
• BExcavation, loading, hauling, and backfilling
• CBlasting, welding, painting, and curing
• DForming, pouring, finishing, and sealing

Pushing downhill (a negative grade) typically does which of the following to dozer production?

• ADecreases blade capacity because the load runs off the blade
• BIncreases the load the blade can carry compared with a level push
• CHas no effect on production
• DRequires switching to a motor grader

Which statement about typical dozer working speed is consistent with Pipe and Excavation Contracting?

• AProduction dozing is commonly in the roughly 1 to 4 mph range, with an average loaded spe…
• BProduction dozing is normally done at highway speeds above 25 mph
• CDozers should never travel faster than 0.25 mph under any condition
• DTravel speed has no effect on hourly production

When a contractor is deciding whether rock can be ripped instead of blasted, which rock type is generally the poorest candidate for ripping?

• ASoft, weathered sedimentary rock
• BFoliated metamorphic rock with open joints
• CMassive, unweathered igneous rock
• DRippable shale

A pad 200 feet by 150 feet must be cut 6 inches. Equipment can move 80 cubic yards per hour. About how many production hours are required (bank measure, no swell)?

• AAbout 1.4 hours
• BAbout 6.9 hours
• CAbout 27 hours
• DAbout 187 hours

A loader-truck spread averages 700 loose cubic yards per hour in soil with a 35 percent swell. What is the equivalent bank production?

• A245 BCY per hour
• B519 BCY per hour
• C700 BCY per hour
• D945 BCY per hour

In production trenching with a backhoe, what is a "set"?

• AThe length of trench the hoe can excavate from one position, made up of digging cycles
• BThe number of trucks assigned to the job
• CThe OSHA soil classification letter
• DThe Proctor moisture content

What two values does a laboratory Proctor compaction test establish for a soil?

• ALiquid limit and plastic limit only
• BMaximum dry density and optimum moisture content
• COSHA soil type and allowable slope
• DCalifornia bearing ratio and frost depth

Relative compaction reported on a field density test is which ratio?

• AField dry density divided by the laboratory maximum dry density, expressed as a percent
• BOptimum moisture divided by liquid limit
• CLoose cubic yards divided by bank cubic yards
• DTrench depth divided by trench width

If a cohesive fill is compacted well below or well above its optimum moisture content, what typically happens?

• AThe soil always exceeds 100 percent of modified Proctor
• BThe dry density achieved is lower than the maximum on the Proctor curve
• CMoisture content no longer matters once the roller is on the lift
• DThe soil automatically becomes OSHA Type A

Which roller is generally the best production choice for compacting heavy cohesive clay fills?

• ASmooth-drum vibratory roller
• BSheepsfoot or tamping-foot roller
• CPneumatic tire roller used only for asphalt
• DStatic grid roller used only to crush rock

Which compaction equipment is generally most effective on clean sand, gravel, or crushed-stone base?

• AStatic sheepsfoot roller
• BVibratory smooth-drum roller
• CSheepsfoot roller with vibration off and feet fully padded with clay
• DA water truck with no roller

Which field method is most commonly used to measure in-place dry density and moisture of compacted fill on a production earthwork job?

• ANuclear density gauge (ASTM D6938)
• BAtterberg liquid-limit device only
• COSHA thumb-penetration test
• DA visual color comparison

Why must structural fill be placed in controlled lifts rather than dumped in one thick layer?

• AThick, uncompacted dumps leave the lower portion of the layer under-densified
• BLifts are required only for landscaping mulch
• COSHA forbids any fill thicker than 2 inches
• DA single thick dump always exceeds 100 percent Proctor

How does the modified Proctor test (ASTM D1557) differ from the standard Proctor test (ASTM D698)?

• AModified Proctor uses greater compactive effort and generally yields a higher maximum dry…
• BModified Proctor uses less energy and always yields a lower maximum dry density
• CThe two methods are identical and interchangeable on every project
• DASTM D1557 measures only Atterberg limits

Under IBC 2021 Section 1804.6, compacted fill 12 inches deep or less that will support a shallow foundation, and that is not designed from a full geotechnical report, must have an in-place dry density of at least:

• A70 percent of ASTM D698
• B80 percent of the standard Proctor
• C90 percent of the maximum dry density at optimum moisture per ASTM D1557
• D100 percent of the nuclear gauge wet density with no laboratory curve

IBC 2021 Section 1804.3 requires foundation backfill to be:

• AAny jobsite debris, provided it is wet
• BSoil free of organic material, construction debris, cobbles, and boulders, placed in lift…
• CUncompacted topsoil only
• DFrozen chunks placed in one lift against the dampproofing

In the sand-cone field density test (ASTM D1556), how is the volume of the test hole determined?

• ABy filling the hole with a calibrated sand of known density and weighing the sand used
• BBy estimating the hole with a tape measure only
• CBy counting roller passes
• DBy reading an OSHA pocket penetrometer

In a narrow utility trench, which handheld compactor is generally preferred for cohesive (clayey) backfill?

• AVibratory plate only, because clay always densifies by vibration
• BRammer (jumping jack), because impact and high unit pressure remold clay
• CSmooth-drum highway roller inside the trench
• DA garden hose with no mechanical compaction

Compacting a clay fill slightly dry of optimum moisture, compared with slightly wet of optimum, typically produces:

• AA more permeable fill with a flocculated structure and often higher strength
• BA completely saturated, impermeable mass with no air voids
• CNo difference in soil structure
• DAutomatic compliance with IBC 90 percent D1557 regardless of density

According to Pipe and Excavation Contracting, puddling (water settling) of backfill, when done correctly, may achieve about what fraction of Proctor density?

• AUp to about 80 percent of Proctor density
• BAlways 100 percent of modified Proctor
• CLess than 20 percent of Proctor density in every soil
• D200 percent of standard Proctor

What is the purpose of proof-rolling a subgrade before placing fill or pavement?

• ATo measure nuclear-gauge moisture in the laboratory
• BTo detect soft, pumping, or under-compacted areas under a heavy loaded vehicle
• CTo classify the soil as OSHA Type A
• DTo replace the need for any density testing on structural fill

A cohesive lift fails a density test because it is too dry. What is the correct corrective action before retesting?

• AAdd a thicker uncompacted lift on top and retest the surface only
• BScarify the lift, add water uniformly, mix, and recompact
• CFlood the lift until standing water remains and immediately roll
• DDeclare the lift Type C soil and waive compaction

Under IBC 2021 Section 1804.3, which backfill material is expressly excepted from compaction?

• AOrganic topsoil
• BControlled low-strength material (CLSM)
• CFat clay dumped in 3-foot lifts
• DConstruction debris

IBC 2021 Section 1804.4 generally requires the ground immediately adjacent to a building foundation to be sloped away at not less than:

• A1 unit vertical in 20 units horizontal (5 percent) for at least 10 feet
• B1 unit vertical in 2 units horizontal for 50 feet
• CA 45-degree slope for 3 feet
• DA level grade so water ponds at the wall

IBC 2021 Section 1705.6 special inspections of soils are used to verify that:

• AFill placement and load-bearing soil work comply with the approved geotechnical report an…
• BThe contractor's payroll tax filings are correct
• COnly the paint color on site trailers meets code
• DBlasting magazines are licensed by OSHA

How does the rubber-balloon field density test (ASTM D2167) measure the volume of the test hole?

• ABy driving a thin-wall cylinder and using the cylinder's internal volume
• BBy pressing a water-filled rubber membrane into the hole and reading the displaced volume
• CBy counting the blows of a standard Proctor hammer
• DBy measuring the unconfined compressive strength in tsf

A nuclear-gauge test on a compacted lift shows a dry density of 114.0 pounds per cubic foot. The laboratory maximum dry density is 120.0 pcf. What is the relative compaction?

• A86 percent
• B95 percent
• C105 percent
• D114 percent

A specification requires 95 percent of ASTM D1557. Another job on the same soil requires 95 percent of ASTM D698. Which statement is correct?

• ABoth targets are the same dry density because both say 95 percent
• B95 percent of D1557 is a higher dry-density target because the modified maximum is higher
• C95 percent of D698 is always the higher dry-density target
• DNeither method produces a maximum dry density