Hydraulic Conductivity - Coursework Example

? Hydraulic conductivity and Hydraulic conductivity Introduction Hydraulic conductivity is the simplicity of water movement, through fractures and porous spaces in rocks or soil, and the level is determined through the computation of the location’s hydraulic gradient and the conditioning of the permeability, as well as the saturation of the material. Hydraulic conductivity is universally determined through an empirical approach, which entails correlating hydraulic conductivity to the properties of the soil. It is also determined through an experimentation process, entailing the calculation of the level of conductivity, experimentally (Deb &, Shukla, 2012). This paper will define hydraulic conductivity and discuss the properties or the states that affect the levels of hydraulic conductivity. Further, the paper will explore the importance of hydraulic conductivity and the methods used for the determination of hydraulic conductivity using empirical-based, field-based and lab-based approaches. The properties and the states that affect hydraulic conductivity The first property is the compaction conditions of the soil or the rock materials, where the difference in hydraulic conductivity depends on the contours of initial saturation. The zones of initial saturation are computed using the following equation: (Brauns, Bieberstein & Reith, 2003) Under the equation, “w is the molding water level; yd is the weight of the dry unit of the soil, yw is the (per-unit) weight of water, and Gs is the particular gravitational level of solids” (Brauns, Bieberstein & Reith, 2003). Defining the water levels in the combination and the weight of the dry unit matches the hydraulic conductivity. The second determinant of hydraulic conductivity is index properties, which is marked by the composition of the soil or the rock material in question. Soils with higher amount of fines and clay, as well as more active minerals of clay will have lower levels of hydraulic conductivity (Ganjian et al., 2006). This is the case, because they contain clay particles that are smaller than other soils and rocks therefore are more likely to have thicker double layers. In the case of soils and rock materials which are composed of larger particles, which are ordinarily less likely to be closely compacted into double layers, levels of hydraulic conductivity are lower (Beckie & Harvey, 2002). The third factor is the atterberg limits of the materials at the given area, where hydraulic conductivity should take place. In general, hydraulic conductivity reduces where there is an increase in the plasticity index and the liquid limit. This is the case, because plastic index and liquid limit are directly connected to the mineralogy of the soil, clay or the rock material in question. Sometimes, an increase in the clay content of a soil or rocky material or the presence of more active minerals of clay leads to a reduction in the size of microscale pores (Deb & Shukla, 2012). These microscale pores are the ones that determine the flow of water in the compacted wet lines of the soil or the rocky materials. This factor implies that soils with higher plasticity index and liquid limits will contain more clay content or active clay minerals, and will characteristically have lower levels of hydraulic conductivity (Ganjian et al., 2006). Also, the particle size distribution of materials influences the hydraulic conductivity of the given material. This means that an increase in the percentage level of the fine particles contained in a unit area of the material causes a decrease in the hydraulic conductivity of the material. For example, soils with high levels of fine clay tend to have lower conductivity levels (Deb & Shukla, 2012). Why hydraulic conductivity is so important Hydraulic conductivity is used for different roles, including the development of engineering models entailing the use of geotechnical designing. Under this use, hydraulic conductivity is necessary for the determination of retaining structures and slope areas, because the levels detected from the soils determine whether they meet the permeability levels required. It helps during engineering processes requiring the determination of the underground water seepage levels of the areas of project development (Singh, 2007). It is also necessary during the development of solutions to the problems related to the pumping of seepage water at construction areas requiring excavation. It is used during the analyses of the stability of earth structures and earth restraining models like walls, which are likely to be affected by seepage forces (Alfaro & Wong, 2001). The second area of use for hydraulic conductivity is the construction of domestic septic systems. It is necessary, because it is the process used for the determination of the soil’s capability to absorb and remove contaminants from the waste water, before dispersing it into the neighboring soil areas (Singh, 2007). Through the determination of the hydraulic conductivity of the soil, waste treatment experts are able to determine the levels, to which the given soil type and the surrounding soil types can aid in the treatment of the waste water and other wastes. At the testing stage, the experts determine whether the soil or rocky area can help in the chemical treatment, physical treatment and the biological treatment of the wastewater (Singh, 2007). At the chemical treatment stages, the soil absorbs the particles from the waste, for example phosphates. At the physical treatment phase, the effluent is absorbed into the pores of the soil, and at the biological treatment phase, the microbial in the soil feed on, and break the pathogens and the organic contaminants in the wastewater (Singh, 2007). Hydraulic conductivity is used for the determination of the suitability of soils and vertisols, during the research for the cultivation of deep-rooted crops in semiarid lands (Pal et al., 2003). Through the determination of the hydraulic conductivity of the soils, the effect of the drainage characteristics of the soils, on the water levels available, helps in the management and planning of soil and other areas of management. The planning and soil management processes are necessary and helpful, because they help in the improvement of the soils at different areas, so that they can aid the efficiency of agro-farming among other drainage dependent activities (Pal et al., 2003). Through the determination of the hydraulic conductivity of soil, soil experts are able to determine whether it is easy or difficult for the soils being tested to allow for water or vapour movement (Hanumantha Rao et al., 2009). The process helps soil experts in determining whether the soils tested can allow for contaminants to be spread across a wider area, or whether it can be contained at the area of contamination. This process entails the determination of the porosity of the soil, the type of soil and the configuration of the pores of the given soil (Hanumantha Rao et al., 2009). Hydraulic conductivity is used in the management of waste materials, because it helps in determining the conductivity of the soils at the target areas of disposal, due to the increasing concern on the environmental friendliness of activities (Daniel & Trautwein, 1994). Through the process, the waste management, experts are useful in altering the hydraulic conductivity of the waste disposal areas, so as to minimize the environmental pollution that takes place during transportation and the disposal of waste. Theis process allows for the testing of the effects of environmental stresses on the channels of waste transportation as well as the target areas of waste disposal (Daniel & Trautwein, 1994). Methods for the estimation of hydraulic conductivity The empirical-based approach During the calculation of the hydraulic conductivity of a soil or rock material empirically, the person testing the sample considers a grain-sized distribution of the material. The method is developed from the general equation, “[K= (g/v)*C*i(n)*(d_e)^2]” (Baird, Surridge & Money, 2004) From the equation, “K= is the hydraulic conductivity of the sample; g = acceleration level, due to gravitational pull; v = is the kinematic viscosity; C = is the sorting coefficient; l(n) = is the porosity function; and d_e = is the effective diameter of the grain. The kinematic viscosity (v) of the sample is determined using the dynamic viscosity (µ) and the density of the water (?) as v= µ/?” (Baird, Surridge & Money, 2004). The levels of “C, ‘(n) and d is computed from the empirical link n = 0.255(1 + 0.83^U). In the given case the coefficient of the uniformity grain (U) can be computed using U=d_60/d_10” (Baird, Surridge & Money, 2004). “From the sample of study, d_60 refers to the diameter of the grains in (mm), where it is 60 percent, in the case that the sample is very fine and d_10 is the diameter of the grains, in mm, where 10 percent of the sample is considerably fine” (Baird, Surridge & Money, 2004). The diverse empirical-based formulas are based on the general equation (Baird, Surridge & Money, 2004). When using the Kozeny-Carman equation for many textures of different soils, the formula is the most generally accepted and used, for empirical derivation based on the size of soil grains. However, it is not very effective when it is used with effective sizes of grains that are more than 3-mm or with clay-like textured soils (Liu, 2001). “[K= (g//v)*8.3*10^ [n^3/91-n) ^2]*(d-10) ^2]” (Liu, 2001) The Hazen equation is useful in the case of soil textures such as the size of sand to gravel, but the soil should have a uniform coefficient of below 5 (U Read More