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Permeability
Published in Braja M. Das, Advanced Soil Mechanics, 2019
The coefficient of permeability depends on several factors, most of which are listed in the following: Shape and size of the soil particles.Void ratio. Permeability increases with increase in void ratio.Degree of saturation. Permeability increases with increase in degree of saturation.Composition of soil particles. For sands and silts, this is not important; however, for soils with clay minerals, this is one of the most important factors. Permeability depends on the thickness of water held to the soil particles, which is a function of the cation exchange capacity, valence of the cations, and so forth. Other factors remaining the same, the coefficient of permeability decreases with increasing thickness of the diffuse double layer.Soil structure. Fine-grained soils with a flocculated structure have a higher coefficient of permeability than those with a dispersed structure.Viscosity of the permeant.Density and concentration of the permeant.
Soils and clay minerals
Published in Hsai-Yang Fang, John L. Daniels, Introductory Geotechnical Engineering, 2017
Hsai-Yang Fang, John L. Daniels
Void ratio and porosity both indicate the proportion of void space in a given soil; the one expresses the volume of void space in terms of the volume of solid matter, the other expresses the volume of void space of the total volume of soil mass. They are related as shown in Table 3.1.
Long-term laboratory investigation on backfill
Published in Manfred Wallner, Karl-Heinz Lux, Wolfgang Minkley, H. Reginald Hardy, The Mechanical Behavior of Salt – Understanding of THMC Processes in Salt, 2017
Low compaction rates in the order of magnitude observed in situ (≤10–10 s–1) cannot be used in the laboratory for an entire experiment because no significant compaction is achieved within a reasonable period of time. Nevertheless low rates are important to determine the in situ behavior, because the compaction rate has a considerable influence on the backfill resistance. The results from tests with applied constant compaction rates between 10–7 and 10–10 s–1 allow comparison of the behavior of different samples. In a stress-porosity (void ratio) plot like in Figure 3 it is possible to obtain results by interpolating and extrapolating the data and curves. The void ratio is the ratio between the pore volume and the solid matter volume of the porous material. The density of the dry solid crushed salt (rock salt) sample is 2.16 g/cm3.
Mechanical behavior and particle crushing of marine carbonate gravel in Xisha Islands, South China Sea
Published in European Journal of Environmental and Civil Engineering, 2023
Figure 3 gives the results of the oedometer test in terms of void ratio versus surcharge pressure. It can be seen from the virgin compression lines in Figure 3 that the void ratio reduces significantly with increasing surcharge pressure, indicating high compressibility of the carbonate gravel. The higher the initial void ratio, the higher the compressibility. Thus, as surcharge pressure increases, the virgin compression line of the loose specimen rapidly approaches that of the dense specimen. At the surcharge pressure of 3200 kPa, the dense specimen has the void ratio of 0.75, dry unit weight of 1.54 g/cm3 and relative density Dr of 0.80; while the loose sand has the void ratio of 0.76, with dry unit weight of 1.53 g/cm3 and Dr of 0.78. If the surcharge pressure were increased further, the two lines might overlap and enter the regime of the limiting compression curve (Pestana & Whittle, 1995), where compression behavior is independent of the initial density of the specimen. Coop (1990) and Wu et al. (2022) also observed a similar phenomenon in the oedometer tests of carbonate sand.
Properties and performance of a high volume fly ash grout
Published in Marine Georesources & Geotechnology, 2020
The development of UCS of grouted soil with curing time can be attributed to the strength development of the fly ash grout, since a similar behavior is also expected for cement based grouts. A similar observation was made for strength-distance and permeability-distance relationships for microfine cement MC-500, which was attributed mostly to the degree of retention of the suspension solids by the sand (Markou and Atmatzidis 2004; Naik 2006). Generally, void ratio decreases with increase in relative density and in parallel, compressive strength increases. In the long samples, grout intake was about 8–10 void volumes near the injection, whereas it was about two void volumes for short samples.
Study on the shear property of nano-MgO-modified soil
Published in Marine Georesources & Geotechnology, 2018
Lei Gao, Ke-yi Ren, Zhen Ren, Xiang-juan Yu
Soil is composed of solid particles, water, and air; soil particles are rotated and bonded to constitute the soil skeleton. For cohesive soil, the shear strength is made up of cohesive component and friction component, which mainly depends on the void ratio, density, and soil water content of soil. The smaller the void ratio , the greater the cohesive force; this effect increases with the decrease in void ratio.