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Effective Stress
Effective stress is a fundamental concept in soil mechanics and geotechnical engineering that describes the portion of total stress in a soil mass that is carried by the solid soil skeleton, rather than the pore water. It is crucial for understanding the mechanical behaviour of soils, as effective stress governs both the strength and volume change (deformation) of soil. More formally, effective stress is defined as the stress that, for any given pore pressure p, produces the same strain or strength response in a porous material (such as soil or rock) as would be observed in a dry sample where p = 0. In other words, it is the stress that controls the mechanical behaviour of a porous body regardless of pore pressure present. This concept applies broadly to granular media like sand, silt, and clay, as well as to porous materials such as rock, concrete, metal powders and biological tissues. History Karl von Terzaghi first proposed the relationship for effective stress in 1925. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morocco Africa Flickr Rosino December 2005 84514010
Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocco border, the east, and the disputed territory of Western Sahara to Morocco–Western Sahara border, the south. Morocco also claims the Spain, Spanish Enclave and exclave, exclaves of Ceuta, Melilla and Peñón de Vélez de la Gomera, and several small Plazas de soberanía, Spanish-controlled islands off its coast. It has a population of approximately 37 million. Islam is both the official and predominant religion, while Arabic and Berber are the official languages. Additionally, French and the Moroccan dialect of Arabic are widely spoken. The culture of Morocco is a mix of Arab culture, Arab, Berbers, Berber, Culture of Africa, African and Culture of Europe, European cultures. Its capital is Rabat, while its largest city is Casablanca. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of The Witwatersrand
The University of the Witwatersrand, Johannesburg (), commonly known as Wits University or Wits, is a multi-campus Public university, public research university situated in the northern areas of central Johannesburg, South Africa. The university has its roots in the mining industry, as do Johannesburg and the Witwatersrand in general. Founded in 1896 as the South African School of Mines in Kimberley, South Africa, Kimberley, it is the third oldest South African university in continuous operation. The university has an enrollment of 37,295 students as of 2025, of which approximately 20 percent live on campus in the university's 17 residences. 63 percent of the university's total enrollment is for Undergraduate education, undergraduate study, with 35 percent being Postgraduate education, postgraduate and the remaining 2 percent being Occasional Students. The university has, as of 2024, an acceptance rate of approximately 4.5%, having received 140,000 applications but only having a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoyancy
Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus, the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the Displacement (fluid), displaced fluid. For this reason, an object with average density greater than the surrounding fluid tends to sink because its weight is greater than the weight of the fluid it displaces. If the objec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaker (glassware)
In laboratory equipment A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools, u ..., a beaker is generally a Cylinder (geometry), cylindrical container with a flat bottom.Oxford English Dictionary 1989 edition Most also have a small spout (or "beak") to aid pouring, as shown in the picture. Beakers are available in a wide range of sizes, from one milliliter up to several liters. A beaker is distinguished from a Laboratory flask, flask by having straight rather than sloping sides. The exception to this definition is a slightly conical-sided beaker called a Philips beaker. The beaker (drinkware), beaker shape in general drinkware is similar. Beakers are commonly made of glass (today usually borosilicate glass), but can also be in metal (such as stainless steel or aluminum) or certain plastic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be used: \rho = \frac, where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate this quantity is more specifically called specific weight. For a pure substance, the density is equal to its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium is the densest known element at standard conditions for temperature and pressure. To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity "relative den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of the processes involved is called tribology, and has a history of more than 2000 years. Friction can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire. Another important consequence of many types of friction can be wear, which may lead to performance degradation or damage to components. It is known that frictional energy losses account for about 20% of the total energy expenditure of the world. As briefly discussed later, there are many different contributors to the retarding force in friction, ranging from asperity deformation to the generation of charges and changes in local structure. When two bodies in contact move relative to each other, due to these variou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slope Stability
Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement; the opposite condition is called slope instability or slope failure. The stability condition of slopes is a subject of study and research in soil mechanics, geotechnical engineering, and engineering geology. Analyses are generally aimed at understanding the causes of an occurred slope failure, or the factors that can potentially trigger a slope movement, resulting in a landslide, as well as at preventing the initiation of such movement, slowing it down or arresting it through mitigation countermeasures. The stability of a slope is essentially controlled by the ratio between the available shear strength and the acting shear stress, which can be expressed in terms of a safety factor if these quantities are integrated over a potential (or actual) sliding surface. A slope can be globally stable if the safety factor, computed along any potential sliding surface running from the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pore Water Pressure
Pore water pressure (sometimes abbreviated to pwp) refers to the pressure of groundwater held within a soil or Rock (geology), rock, in gaps between particles (soil pore, pores). Pore water pressures below the phreatic level of the groundwater are measured with piezometers. The vertical pore water pressure distribution in aquifers can generally be assumed to be close to Hydrostatic pressure, hydrostatic. In the Vadose zone , unsaturated ("vadose") zone, the pore pressure is determined by capillary action, capillarity and is also referred to as Tension (physics), tension, suction, or matric pressure. Pore water pressures under unsaturated conditions are measured with Tensiometer (soil science), tensiometers, which operate by allowing the pore water to come into equilibrium with a reference pressure indicator through a permeable ceramic cup placed in contact with the soil. Pore water pressure is vital in calculating the stress state in the ground soil mechanics, from Karl von Terzag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
