1. 0. 1 This Code is set down to unify the technical standard for design of railway subgrade to meet the requirements on safe application, technical advancement and economic rationalization in the design of subgrade.
1. 0. 2 This Code is used to the design of subgrades for Class Ⅰ and Ⅱ standard gauge railway within railway network where passenger train and freight train travel on the same line, the design running speed for passenger train is equal to or less than 160 km/h and the design running speed for freight train is equal to or less than 120 km/h.
1. 0. 3 The vertical live load of trains on railway must apply the CS-live land. The live load of tacks and trains shall use conversion soil column instead, the height and distribution width of conversion soil column shall conform to the previsions set forth in Appendix A hereof.
1. 0. 4 Subgrade engineering shall carry out geological mapping, adequate prospection and tests to ascertain the rock and soil structures and its physical-mechanical properties in the base of foundation, cutting slope and retaining structure, etc, ascertain unfavorable geological conditions, ascertain filling property and distribution and conduct designs on the basis of reliable geological data.
1. 0. 5 Subgrade engineering shall be designed according to civil structures. in which its foundation(ground)treatment, embankment construction, retaining structure and protection of side slope and drainage facility, etc, must have sufficient strength, stability and durability to withstand the influence of various physical factors.
1. 0. 6 Subgrade engineering design shall avoid high fill, deep excavation and long cutting and go round, if it is possible, the sections with unfavorable geological conditions. In the comparative selection of subgrade and bridge or tunnel engineering, type of engineering shall be determined through comprehensive analysis based on technical conditions, construction conditions, the possible impacts to environment and society, construction investment and costs for operation and maintenance, etc.
1. 0. 7 In the section with dense Class Ⅰ railway bridges, when the subgrade length between two bridge abutment ends is less than 150m which can meet the technical conditions to set bridge, bridge shall be built instead of subgrade.
1. 0. 8 Foundation for subgrade engineering shall meet the requirements on bearing capacity and post-acceptance settlement of subgrade. The measures to be taken to treat foundation must be determined through calculations based on railway classification, geological data, embankment height, filling and construction period, etc.
1. 0. 9 Subgrade packing shall be surveyed and designed as engineering materials. The cut-fill trasition of subgrade shall ensure that fillings in each portion of subgrade meet the requirements of packing standard and conform to the principle of land saving. The rational programming shall be drawn before design through technical and economical comparisons to schemes for cut-fill transition, concentrated borrowing(dumping)soil and improvement of filling, etc.
