Design note:1. A transition section

Design note:1. A transition section shall be provided at the embankment-culvert junction. Technical requirements are as follows: 1.1 Length of the transitional section between embankment and culvert is L=2+(H-h1)×2 (H is embankment height and h1 is the distance between culvert top and formation level). 1.2 The packing and compaction standard of the surface layer of subgrade bed in transitional section shall be the same as that of surface layer of neighboring subgrade bed; the part below surface layer of subgrade bed shall use the same filler as the surface layer; when transition section is immersed, packing of the immersed section (the part below common water level) shall also meet the requirements for permeable material, and their compaction standard shall meet the requirements on the bottom layer of subgrade bed in code. When particles sizes of packing on both upper and lower layers are quite different, a granular filter material (bed course) with thickness of 0.3m shall be laid on the interface.1.3 When the structures have been finished firstly, the construction of transition section and embankment nearby shall be done after the strength of structure concrete meets the design requirement. 1.4 The foundation pit below flow surface of both side of culvert shall be backfilled with concrete. When ground water level is high, the part below ground water level in culvert pit shall be backfilled with permeable material like sand mix with crushed stone.1.5 The area closed to culvert where it is difficult for large roller machine to operate, small vibrating roller machine shall be used to ensure full compaction. 2. Unless otherwise indicated, the dimensions in the drawing are measured in m."