Rate Analysis of Excavation in Earthwork

• Rate analysis of excavation in earthwork use of IS Code 1200 part 1, Part 27, IS 4988, IS 12138 (Part IV) and CPWD for calculation is this measurement of the quantity of excavation to be carried out, the cost of labour, machinery, and other equipment like hard soil for breaker, etc.
• Rate analysis of excavation depends on the depth of excavation, depending on soil type, also depends on the method of excavation to be carried out and the distance where the soil has to be disposed of.  The cost of all these is added for a unit volume of excavation to get the rate of excavation.

Work to be Measured Separately

• Rate analysis of earthwork excavation of the different area and location rate analysis different executed in the following conditions shall be measured separately:
  • Work in or underwater,
  • Work in or under foul situations,
  • Work under tidal conditions, and
  • Work in snow.

Also, read: What is Rate Analysis| Rate Analysis of Earth Work, Brick, Concrete, Plaster

Rate Analysis of Excavation in Earthwork as per Depth 

• The cost of excavation based on different depth is generally divided into categories as per CPWD category (CPWD full name Central Public Works Department )
  • Depth up to 1.5 m.
  • Depth between 1.5 m. to 3.0 m.
  • Depth between 3.0 m. to 4.5 m.
  • Depth of more than 4.5 m.

Rate Analysis of Excavation in Earthwork as Classification. 

• The materials to be excavated will be classified as follows unless otherwise specified.
  • Soft/Loose Soil
  • Hard/Dense Soil
  • Mud
  • Soft/Disintegrated Rock
  • Hard Rock (Requiring Blasting )
  • Hard Rock ( Blasting Prohibited) 

Also, read: Type of Stair | Stairs Parts Names & Details

• Soft/Loose Soil

  • Generally, any soil which yields into the ordinary application of pick and shovel, or to phawra. Rake or another ordinary digging implement, such as vegetable or organic soil, turf, gravel, sand, silt, loam, clay peat, etc.

• Hard/Dense Soil

  • Generally, any soil which requires this close application of picks, or jumpers or scarifiers to loosen, such as stiff clay, gravel, cobblestone, water-bound macadam, and soling of roads.

• Mud

  • A mixture of water and soil and in fluid or weak solid state.

• Soft/Disintegrated Rock

  • Rock or boulders, which can be. Quarried or split with crowbars. The will also include laterite and hard conglomerate.

Also, read: What is BoQ | BoQ Meaning |Advantages of BoQ | What is BoM

• Hard Rock (Requiring Blasting )

  • Any rock or boulder for this excavation of which blasting is required.

• Hard Rock ( Blasting Prohibited)

  • Hard rock requiring blasting as described under but where blasting is prohibited for any reason, and excavation has to be carried out by chiseling, wedging, or any other agreed method.

Bills of Quantities

• The bills of quantities will fully describe the workmanship and materials and accurately represent the work to be executed.
• The following works shan’t be measured separately and allowance to this. Same will be deemed into have been made from the description of the main item:
  • Setting out works, profiles, etc.
  • Site clearance, like cleaning grass and vegetation
  • Unauthorized battering or benching or excavation.
  • Forming ‘dead men’ and ‘tell tales’ in borrow pits and their removal after measurements.
  • Forming steps insides of deep excavation and their removal following measurements.
  • Excavation for insertion of strutting and planking.
  • Unless otherwise specified, removing slips or falls in excavations.
  • Bailing out or pumping of water at excavation from rains.

Also, read: What Is EDM in Surveying | Type | Errors

Most Important Factor of Rate Analysis of Excavation in Earthwork

• • Type of Soil 
  • Transport and lead distance for carrying excavated soil
  • Depth of excavation
  • Method of excavation – mechanical excavation or manual excavation 
  • The capacity of labor for manual excavation
  • The capacity of equipment for mechanical excavation and their cost per unit quantity.
  • Extra Charges (LumSum)
  • Water charges if used
  • Profit of contractor

Example of Rate Analysis of Excavation in Earthwork

• Earthwork in excavation by mechanical means (Hydraulic excavator)/manual means over areas (exceeding 30 cm in-depth, 1.5 m in width as well as 10 sqm on the plan) including getting out and disposal of excavated earth lead up to 50 m and lift up to 1.5 m, as directed by Engineer-in-charge.

• Above all rate took in CPWD Part 1 book
• As per the above calculation of Backhoe excavator work 30 cu.m. per.hour.
• But extra time transition, led, lifting, and extra time detected 15% of the working time of excavation machinery.
• So, the minimum 25 cu.m. per hour working of excavation by using backhoe machinery.
  • Backhoe Excavator
    • Calculation of Backhoe Excavator for 10 Cu.m. Because of the rate analysis, 10 cu.m.
      • Backhoe Excavator =25 cu.m of per hour

= 25 x 8 hour (Per Day work 8 hours consider)

= 200 Cu.m. per day work Backhoe Excavator

• • • • So, 10 cu.m. work for = 0.050 Days required
      • As per Backhoe Excavator =Tractor/Dumper
    • The cost of a Backhoe excavator machine for 10 m³  = 0.050 Day x 7000 Rs. (This took in CPWD)
    • As per the same calculation for Tractor/Dumper = 0.050 Day x 2000 Rs. (This took in CPWD)
  • Likewise, dependent on the capacity of additional equipment, labors, etc., their cost is calculated.
  • The contractor’s profit can be added to the total cost of labors and machinery.
  • Then the grand total gives the rate of excavation per 10 m³ of soil excavation.
  • Different mechanical equipment has different capacity per day for excavation work.
  • Their coefficient per m³ or a 10m3 ought to be considered for calculation.

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