Soil mechanics weathering of feldspar, which is the most common mineral present in igneous rock. The most common mineral constituent of silt and sand is quartz, also called silica, which has the chemical name silicon dioxide. The reason that feldspar is most common in rocks but silica is more prevalent in soils is that feldspar is much more soluble than silica. Silt, Sand, and Gravel are basically little pieces of broken rocks. According to the Unified Soil Classification System, silt particle sizes are in the range of 0.002 mm to 0.075 mm and sand particles have sizes in the range of 0.075
Internal erosion a larger cavity. The process continues until the formation of a sinkhole. It is possible for a cavity to not collapse; this will lead to backward erosion occurring. Soil contact erosion can occur between any granular layer and a finer soil such as in silt-gravel, and often results in a loss of stability, increases in pore pressure and clogging of the permeable layer. Experimental results show that close to the geometrical limit, the point at which the fine particles can "just pass" between the coarse particles(the filter criterion), erosion initiation and failure are much more likely. It is possible to