Analysis of a case study on pile foundation construction based on calculation rules and formulas for construction work quantities

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Analysis of examples related to pile foundation construction using the rules and formulas for calculating construction quantities in building projects. I. Driving or pressing precast reinforced concrete square piles: 1. The volume of precast reinforced concrete piles is calculated based on the designed pile length; the length taken into account is the total length including the pile tip, with no deduction for the virtual volume of the pile tip. Unit of measurement: m3. The formula for calculating volume is as follows: V = cross-sectional area of the pile × designed length of the pile (including the length of the pile tip). 2. Driving reinforced concrete square piles: When the design requires that the top of the reinforced concrete pile be driven below the ground surface, a pile driver must use a guide pile to accomplish this task. This process of using a guide pile – which is usually 2–3 meters long and made of hardwood or metal – to drive the pile is called “pile driving”. The calculation method is stipulated in the quota: the volume is calculated by multiplying the pile driving length—that is, the distance from the top surface of the pile to the natural ground level plus 0.5 meters—by the cross-sectional area, with the unit of measurement being cubic meters. The formula is as follows: V = Cross-sectional area of pile × (Pile driving length + 0.5 m). The pile driving length refers to the distance from the designed pile top elevation to the natural ground level. 3. Pile splicing: Pile splicing refers to the process of prefabricating the piles in sections according to design requirements and transporting them to the site; the first pile is driven into the ground first, then the second pile is lifted vertically and connected to the first pile, after which further pile driving proceeds. Sulphur cement – unit of measurement: m2 ； By pile cross-sectional area: Welded piles – Unit of measurement: t ； Based on the weight of the wrapped angle steel or steel plate. II. Drilling and pressing of prestressed reinforced concrete pipe piles: The volume is calculated based on the designed pile length, with the length including the full length of the pile tip; the virtual volume of the pile tip is not deducted, while the hollow volume of the pipe pile must be taken into account. When concrete or other filling materials are required to be poured into the hollow part of the pipe pile as per the design requirements, this volume should be calculated separately. Unit of measurement: m3. The formula for calculating volume is as follows: V = Cross-sectional area of the pile × Designed pile length (including the length of the pile tip). For calculating the volume of material poured into the pile, the unit of measurement is also m3: V = Cross-sectional area of the inner diameter of the pile hole × Designed depth of pouring. III. Poured piles (1) Piles formed by drilling and inserting tubes – Single insertion or multiple insertions: Unit of measurement: m3. V = Cross-sectional area of the outer diameter of the tube × (Designed pile length + Additional pouring length). Designed pile length – Determined according to the dimensions specified in the design drawings; this includes the length of pre-made pile tips, but not those made of pre-fabricated reinforced concrete. Additional pouring length – Used to ensure that the concrete is poured to the required level, as specified in the design ； If not specified, it shall be taken as 0.25m. (2) Rammed expansion piles: Unit of measurement: m3. V1 (first and second ramming stages) = Cross-sectional area of the inner diameter of the standard pipe × Designed length for ramming and material insertion (excluding the pre-made pile tip). V2 (concrete poured into the pipe at the end) = Cross-sectional area of the outer diameter of the standard pipe × (Designed pile length + 0.25). The designed length for ramming and material insertion is calculated in accordance with the design specifications. (3) Volume of hole formation for bored concrete piles; unit of measurement: m³. Volume of soil drilled, V = cross-sectional area of the pile diameter × depth from the natural ground surface to the rock surface ； For rock drilling holes, V = cross-sectional area of the pile diameter × depth into the rock. The volume of concrete to be poured is measured in m3. V can also be calculated as V = cross-sectional area of the pile diameter × effective pile length; the effective pile length is specified in the design specifications. If no such specifications exist, the following formula is used: Effective pile length = designed pile length (including the length of the pile tip) + pile diameter. The designed pile length refers to the distance from the top of the pile to the bottom of the pile. The additional length required for pouring concrete into the foundation is calculated separately according to the design requirements. Mud transportation volume: Unit of measurement: m3; the volume is calculated based on the volume of holes drilled. IV. Manually dug piles
(1) Volume of manual excavation: Unit of measurement: m³
V (manual earth excavation) = Cross-sectional area outside the retaining wall × Length of the drilled hole
Length of the drilled hole – distance from the natural ground level to the designed pile bottom elevation
V (for silt, flowing sand, or rock) = Actual volume excavated (or chiseled).
(2) Volume of brick/concrete retaining walls and concrete filling within the piles: Unit of measurement: m³
The volume is calculated based on the actual volume defined by the design dimensions.

V. Cement mixing piles and powder jet grouting piles are measured in cubic meters.
V = (Designed pile length + 500 mm) × Cross-sectional area of the designed pile (if a specific length is specified in the design, then that length should be used). The quantity for double axes shall not be calculated repeatedly, and the overlap between pile groups is not deducted. VI. For bored cast-in-place piles using the long spiral or auger method, the volume is calculated in cubic meters as V = (design pile length + 500 MM) × design pile cross-sectional area or the outer diameter area of the spiral (the length shall be based on the design value if specified). VII. Drilling of holes for anchor and shotcrete wall reinforcement in foundation pits and grouting inside the holes. Calculated based on the design drawings in terms of extended meters. 8. Shotcrete for retaining walls: calculated based on the design drawings in terms of square meters.