1.0.1 This standard is formulated with a view to unifying technical requirements for design and construction of cast in-situ pile of harbour engineering, achieving advanced technology, economy and rationality, safety and usability, and effectively controlling the quality.
1.0.2 This standard is applicable to the design, construction, testing and quality control for non-rock-rocketed cast in-situ pile. Ship building and repair engineering and navigation engineering may refer to it. Design and construction for rock-socketed cast in-situ pile shall comply with the relevant requirements of the current professional standard "Design and Construction Code of Rock-socketed Piles for Harbour Engineering" (JTJ 285).
1.0.3 This standard shall be used in conjunction with the current professional standard "Load Code for Harbour Engineering" (JTJ 215), "Code for Pile Foundation of Harbour Engineering" (JTJ 254), "Design and Construction Code for Open Type Wharf on Piles" (JTJ 291), "Design Code for Harbour Engineering Concrete Structures" (JTJ 267) and "Specifications for Concrete Construction of Port and Waterway Engineering" (JTJ 268).
1.0.4 Design and construction for cast in-situ pile of harbour engineering shall not only meet the requirements of this standard but also the relevant requirements of the current national standards.
2 Symbols
2.0.1 A——Sectional area of pile body.
2.0.2 As——Sectional area of steel bar.
2.0.3 b0——Conversion width of pile.
2.0.4 Cu——Standard value of undrained shear strength of soil.
2.0.5 d——Design diameter of pile.
2.0.6 ds——Diameter of steel bar.
2.0.7 d0——Radius of the circle at which the center of longitudinal steel bar of pile body is located.
2.0.8 Ec——Elasticity modulus of concrete.
2.0.9 EP——Elasticity modulus of pile.
2.0.10 E0——Compression modulus of soil.
2.0.11 Es——Elasticity modulus of steel bar.
2.0.12 G——Pile gravity.
2.0.13 H——Horizontal force acted on pile top.
2.0.14 H0——Horizontal force acted on mud surface of pile.
2.0.15 ——Conversion depth coefficient.
2.0.16 I0——Inertia moment of transformed section of pile body.
2.0.17 Ip——Section inertia moment of pile.
2.0.18 K——Effective length coefficient of pile.
2.0.19 k2——Depth correction coefficient of allowable bearing capacity of foundation.
2.0.20 L——Length of pile body.
2.0.21 Li——Length of pile body passing through the ith layer of soil.
2.0.22 L0——Free length of pile above mud surface.
2.0.23 Lp——Buckling calculation length of pile.
2.0.24 Lt——Buried depth of pile.
2.0.25 M——Moment acted on pile top.
2.0.26 m——Proportionality coefficient that horizontal resistance coefficient of foundation soil at pile side increases with depth.
2.0.27 m0——Bottom cleaning coefficient.
2.0.28 M0——Moment acted on mud surface of pile.
2.0.29 Mmax——Maximum bending moment of pile body.
2.0.30 Q——Vertical load acted on pile top.
2.0.31 Qd——Design value of vertical ultimate bearing capacity of single pile.
2.0.32 qfi——Standard value of ultimate lateral resistance of the ith layer of soil for single pile.
2.0.33 [q0]——Allowable bearing capacity of foundation.
2.0.34 qR——Standard value of ultimate resistance of single pile tip.
2.0.35 S——Center distance between piles.
2.0.36 T——Relative rigidity coefficient of pile.
2.0.37 Td——Design value of pull-out ultimate bearing capacity of single pile.
2.0.38 t——Depth from bending embedded point of pile to mud surface.
2.0.39 ——Buried depth of pile below mud surface to assumed embedded point.
2.0.40 U——Sectional circumference of pile body.
2.0.41 Y0——Horizontal displacement of pile at mud surface.
2.0.42 [Y0]——Horizontal displacement limit value of pile at mud surface.
2.0.43 Wmax——Maximum crack width.
2.0.44 [Wmax]——Limit value of maximum crack width.
2.0.45 W0——Moment of elastic resistance of transformed section tension edge of pile body.
2.0.46 Zm——Depth from mud surface to maximum bending moment point of pile body.
2.0.47 α——Deformation coefficient of pile.
2.0.48 α0——Included angle of pile axis and vertical line.
2.0.49 αE——Ratio of the elasticity modulus of steel bar to the elasticity modulus of concrete for pile body.
2.0.50 ——Weight density of soil.
2.0.51 ——Natural weight density of soil above pile tip.
2.0.52 ——Significance coefficient of structure.
2.0.53 ——Partial coefficient of bearing capacity of single pile.
2.0.54 εi——Reduction coefficient.
2.0.55 η——Coefficient.
2.0.56 λ——Correction coefficient.
2.0.57 ρ——Ratio of reinforcement of pile body section.
2.0.58 ——Stability coefficient of pile.
2.0.59 ——Internal friction angle of soil.
3 Basic Requirements
3.0.1 Harbour engineering should adopt cast in-situ pile under the following conditions:
(1) When the geologic condition is complex, the rock face has relatively large fluctuation or underground obstructions are more and driven pile is difficult to sink;
(2) When the load of a single pile is relatively large and the driven pile is uneconomic;
(3) When bank is not stable or there is important building nearby, and pile sinking should not be hammered;
(4) When large overwater pile sinking equipment should not be used due to limited construction conditions, fewer piles, narrow water area or insufficient water depth.
3.0.2 The combination of cast in-situ pile and other types of piles may be adopted in the identical framed structure of high-pile wharf.
3.0.3 Cast in-situ pile of harbour engineering may be divided into cast-in-situ bored pile and cast-in-situ excavated pile according to the method of hole forming. Cast in-situ pile should adopt vertical pile; if conditions permit, inclined pile may also be adopted.
3.0.4 Bearing capacity of pile shall be calculated respectively by the bearing capacity of pile body and the bearing capacity of foundation soil for pile according to different load carrying conditions, and the smaller value shall be taken.
3.0.5 For actual action which may emerge in pile body simultaneously, action effectiveness combination shall be carried out according to the limit state of bearing capacity of pile and the limit state of normal use as well as corresponding design status.
3.0.6 Pile, under the following conditions, shall be designed according to the limit state of bearing capacity:
(1) Calculate vertical bearing capacity and horizontal force of pile according to its load carrying conditions;
(2) Check the bearing capacity of weak underlying layer when weak underlying layer is available below the pile tip plane;
(3) Calculate for compression, bending, tension or torsion bearing capacity of pile body;
(4) Calculate buckling stability of pile when the free length of pile is relatively large.
3.0.7 Pile, under the following conditions, shall be designed according to the limit state of normal use:
(1) Limited crack width of pile body;
(2) Horizontal displacement of pile.
3.0.8 The design of cast in-situ pile foundation shall meet the requirements of the building to settlement and horizontal displacement.
3.0.9 Concrete quality of cast in-situ pile shall be strictly controlled, and reliable testing means shall be taken for evaluation of pile body concrete soundness.
