Structural Studies of Frictional Sediments

The reactions of pebbles, granules and sand grains to different flow—sediment—bed conditions under varying flow energy input are discussed and investigated theoretically and experimentally with special regard to the relaxation of sedimentary structures and their corresponding fabrics. Some aspects are given of dynamic conditions affecting the stability, erosion, transport and deposition of particles of different sizes and shapes in non-uniform frictional sediments under varying flow conditions.Different types of imbrication are related to particle geometry, flow velocities, flow separation, bed resistance to deformation, contacts of the particles, sediment transport, and time. Stability—erodibility of the particles at varying orientation is shown to depend on the support, angle of flow attack, particle exposure, and fluctuations of flow directions and tractive force.The response of gravelly sand beds to the flow energy input by development of gravelly transport—erosion surfaces, gradually stabilizing as imbricated pebble pavements, is demonstrated at different bed slopes under 2- and 3-dimensional geometry.Bed structures and forms of coarse-grained 2- and 3- dimensional delta bodies are related to the flow traction, flow separation, gravity pull, friction, and sediment segregation in backset, topset, foreset and bottomset beds.The results are shown in diagrams and tables. Conclusions and summaries are found at the end of each chapter. A key to interpret the sedimentary environment from textural and structural data is devised in Ch. 10.