1.0.1 This code is formulated with view to unifying the technical standards for design of railway bridge and culvert, implementing the relevant national laws and regulations and railway technology policy, so that the design of subsoil and foundation of railway bridge and culvert meet the requirements for safety and applicability, advanced technology and economical rationality.
1.0.2 This code is applicable to the design of subsoil and foundation of bridge and culvert for Class I, II standard gauge railway on which the passenger and freight trains share the same line and the design running speed of passenger train and freight train does not exceed 160km/h and 120km/h (80km/h for steering 8A freight train) respectively.
1.0.3 Where this code is adopted for design, the load shall meet the requirements of current "Fundamental Code for Design on Railway Bridge and Culvert" (TB 10002.1) issued by the Ministry of Railways shall apply, and the design of base structure shall meet the requirements of the current standards "Code for Design on Reinforced and Prestressed Concrete Structure of Railway Bridge and Culvert" (TB 10002.3) and "Code for Design on Concrete and Block Masonry Structure of Railway Bridge and Culvert" (TB 10002.4). In case of double-layer container train or freight train running at a speed of 120km/h, or non-ballast deck applied on the bridge, the design shall also meet those specified in relevant provisions.
1.0.4 The subsoil and foundation of bridge and culvert shall be so designed to guarantee adequate strength, rigidity, stability, durability, settlement control in accordance with the relevant requirements and 100-year service life.
1.0.5 The type of bridge and culvert foundation shall be appropriately selected according to the requirements for hydrology, geology, terrain and settlement control, as well as the superstructure, load, material supply and construction conditions.
1.0.6 The geological exploration of bridge and culvert foundation shall be strengthened; the geological exploration data shall satisfy the requirements for ascertaining the geological structure, the physical and mechanical property of subsoil rock, the groundwater status and potential unfavorable geologic phenomena which affect the stability of bridge and culvert or may occur during construction. The engineering and property classification of soil and rock shall meet the requirements of Appendix A hereof.
The engineering geological exploration shall be particularly strengthened when the foundation is constructed on the fault in the bridge site, or the subsoil with partial soft soil layer buried in karst or non-uniform stratum, or on uneven or tilted stratum.
1.0.7 The foundation shall be constructed on the subsoil with nonuniform hardness.
The abutment shall be kept away from unfavorable geology such as fault, landslide, compressive rupture zone, limestone cave and karren, loess settlement cave, hidden cave or partial soft subsoil.
Attention shall be paid to the stability of rock mass under the foundation where the abutment is constructed on steep hillside.
As for the abutment by the river channel near the steep palisades, the foundation on the riverbed shall not pass through the stack layer of rocks falling from the underwater palisades.
Open cut foundation and open caisson foundation should not be constructed on subsoil with tilted rockface and difficult in pumping water.
1.0.8 The design of bridge and culvert foundation shall take account of the frost heaving of subsoil. See Appendix A for the frost-heave grade of seasonal frozen soil and the classification of permafrost.
1.0.9 The base embedment depth of open cut foundation and open caisson foundation of abutment shall meet the following requirements:
1 At least 0.25m below the frost line for frost-heaving, strong frost-heaving and extra strong frost-heaving soil, except for the non-frost-heaving soil; at least the frozen depth for weak frost-heaving soil.
2 At least 2.0m below ground where there is no scouring or anti-scour pavement is constructed; at least 1m in especially difficult cases.
TB 10002.5-2005 The following standards are cited：
