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Erosion Sediment Control
Published in Mritunjoy Sengupta, Environmental Impacts of Mining, 2021
Soil erodibility is a function of:The quality of vegetative and coverThe soil gradation and permeabilityThe degree of soil compactionClay mineralogyThe slope gradesThe slope lengthThe quantity of water collected by the slope
Subsurface drainage systems
Published in Willem F. Vlotman, Lambert K. Smedema, David W. Rycroft, Modern Land Drainage, 2020
Willem F. Vlotman, Lambert K. Smedema, David W. Rycroft
The stability of the soil may also be expressed by means of the coefficient of uniformity (Cu) of the soil gradation curve: Cu=d60d10where:Cu = the coefficient of uniformitydxx = the particle size at 60 and 10 percent passing (see Box 8.2 and Figure 8.10) The coefficient of uniformity and the Plasticity Index are indicators of the tendency to siltation and with caution may be taken as an indicator of the need for an envelope (Table 8.2).
Erosion Sediment Control
Published in M. Sengupta, Environmental Impacts of Mining, 2018
Soil erodibility is a function of: The quality of vegetative and coverThe soil gradation and permeabilityThe degree of soil compactionClay mineralogyThe slope gradeThe slope lengthThe quantity of water collected by the slope
Numerical modelling of seepage through earthen dams with animal burrows: a case study
Published in Journal of Hydraulic Research, 2021
Melih Calamak, Lindsey A. Larocque, M. Hanif Chaudhry
For the characterization of collected soils from the five dams, seven geotechnical tests were conducted for the soil gradation, water content, unit weight, permeability, porosity and the LL. All geotechnical experiments were conducted with reference to Bardet (1997) and related ASTM standards. For the soil gradation, sieve analysis and Coulter counter tests were performed. The particle size distribution of each embankment material for the sediment coarser than 0.075 mm was determined from standard sieve analysis conducted with sieve numbers 10, 40, 60, 100, 120 and 200. The grain size distribution of material finer than 0.075 mm was measured with the Beckman Coulter counter MS4. The Coulter counter uses an impedance measurement technique to detect particles via electrical zone sensing (Beckman Coulter, 2009). The coefficient of curvature, Cc = (D30)2/(D10×D60), the coefficient of uniformity, Cu = D60/D10, in which Dx is the grain size such that x% of the sediment is finer, were determined. Based on the gradation test results, the soil types were determined using the Unified Soil Classification System. The soil gradation curves are given in Figure Fig. 4. The water content of soils, wc, was measured in the laboratory using the oven-drying method. The soil samples were oven-dried at a temperature of 110°C to a constant mass, and the change in the mass was considered to be water (ASTM International, 2010). The dry unit weight of soils was determined with oven-dried samples with the standard mould of known volume (ASTM International, 2000a). The hydraulic conductivity, K, of soils was determined by a constant head test conducted in a permeameter with a diameter of 76 mm. The permeameter was filled with soil in layers, and each layer was compacted to the maximum density with a sliding weight tamper. It was then connected to a constant-head tank, and the time, head, and the quantity of flow were measured. The test and calculations were conducted in accordance with ASTM International (2006). The LL tests were performed with a hand-operated Casagrande apparatus. The soils were processed with No. 40 sieve and retained material was removed. The specimen was wetted with distilled water and spread in the cup of the apparatus. The soil in the cup was cut into two with the grooving tool and then allowed to re-join by the shocks created from repeatedly dropping the cup (ASTM International, 2000b). The porosity was determined with a graduated cylinder and water by measuring the volume of water required to fill the voids of the soil. The results for geotechnical tests are listed in Table 3.