Tieback (geotechnical)

A tieback is a horizontal wire used to reinforce retaining walls for stability. With one end of the tieback secured to the wall, the other end is anchored to a stable structure, such as a concrete deadman which has been driven into the ground. The tieback-deadman structure resists forces that would otherwise cause the wall to lean, as for example, when a seawall is pushed seaward by water trapped on the landward side after a heavy rain.

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A retaining wall is a structure that holds back soil or rock from a building, structure or area. Retaining walls prevent downslope movement or erosion and provide support for vertical or near-vertical grade changes.
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A seawall is a form of hard coastal defence constructed on the inland part of a coast to reduce the effects of strong waves and to defend the coast around a town or harbour from erosion. The walls can be sloping, vertical or curved to reflect wave power.
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Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering includes investigating existing subsurface conditions and materials; assessing risks posed by site conditions; designing earthworks and
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SOiL is a five-piece Hard Rock band from Chicago, Illinois, United States. They formed in 1997 and are still active. They are signed to DRT Entertainment and have released four albums, their most recent being True Self which was released in March 27 2006.
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Clay is a naturally occurring material, composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried or fired.
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Silt is soil or rock derived granular material of a specific grain size. Silt may occur as a soil or alternatively as suspended sediment in a water column of any surface water body. It may also exist as deposition soil at the bottom of a water body.
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Sand is a granular material made up of fine mineral particles. It is a naturally occurring, finely divided rock.

Sand comprises particles, or granules, ranging in diameter from 0.0625 (or 116 mm) to 2 millimeters.
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Gravel is rock that is of a certain particle size range. In geology, gravel is any loose rock that is at least two millimeters (2mm) in its largest dimension (about 1/12 of an inch) and no more than 75 millimeters (about 3 inches).
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Peat is an accumulation of partially decayed vegetation matter. Peat forms in wetlands or peatlands, variously called bogs, moors, muskegs, pocosins, mires, and peat swamp forests.
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Hydraulic conductivity, symbolically represented as , is a property of vascular plants, soil or rock, that describes the ease with which water can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and on the degree of saturation.
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Water content or moisture content is the quantity of water contained in a material, such as soil (called soil moisture), rock, ceramics, or wood on a volumetric or gravimetric basis.
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Void ratio, in materials science, is defined as the volume of voids in a mixture divided by the volume of solids. This figure is relevant in composites, in mining (particular with regard to the properties of tailings), and in soil science.
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Bulk density a property of particulate materials. It is the mass of many particles of the material divided by the volume they occupy. The volume includes the space between particles as well as the space inside the pores of individual particles.
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Thixotropy is the property of some non-newtonian pseudoplastic fluids to show a time-dependent change in viscosity; the longer the fluid undergoes shear stress, the lower its viscosity.
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Reynolds' dilatancy is the observed tendency of a compacted granular material to dilate (expand in volume) as it is sheared. This occurs because the grains in a compacted state are interlocking and therefore do not have the freedom to move around one another.
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The angle of repose, also referred to as angle of friction, is an engineering property of granular materials.
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Cohesion is the component of shear strength of a rock or soil that is independent of interparticle friction.

In soils, true cohesion is caused by one of three things:
  1. Electrostatic forces in stiff overconsolidated clays (which may be lost through weathering)

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Porosity is a measure of the void spaces in a material, and is measured as a fraction, between 0–1, or as a percentage between 0–100%. The term porosity is used in multiple fields including manufacturing, earth sciences and construction.
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In the earth sciences, permeability (commonly symbolized as κ, or k) is a measure of the ability of a material (typically, a rock or unconsolidated material) to transmit fluids.
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Specific storage (Ss), storativity (S), specific yield (Sy) and specific capacity are aquifer properties; they are measures of the ability of an aquifer to release groundwater from storage, due to a unit decline in hydraulic head.
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Soil mechanics is a discipline that applies principles of engineering mechanics, e.g. kinematics, dynamics, fluid mechanics, and mechanics of material, to predict the mechanical behavior of soils.
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Karl von Terzaghi first proposed the relationship for effective stress in 1936. [1] For him, the term ‘effective’ meant the calculated stress that was effective in moving soil, or causing displacements.
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Pore water pressure refers to the pressure of groundwater held within a soil or rock, in gaps between particles (pores). For example, in a high permeability soil, the pressure would be close to hydrostatic in no flow conditions.
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Shear strength in reference to soil is a term used to describe the maximum strength of soil at which point significant plastic deformation or yielding occurs due to an applied shear stress.
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Overburden pressure, lithostatic pressure, and vertical stress are terms that denote the pressure or stress imposed on a layer of soil or rock by the weight of overlying material.
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Consolidation is a process by which soils decrease in volume. It occurs when stress is applied to a soil that causes the soil particles to pack together more tightly, therefore reducing its bulk volume.
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Soil compaction occurs when weight of livestock or heavy machinery compresses soil, causing it to lose pore space. Affected soils become less able to absorb rainfall, thus increasing runoff and erosion.
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Soil classification deals with the systematic categorization of soils based on distinguishing characteristics as well as criteria that dictate choices in use.

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S-wave, secondary wave, or shear wave, sometimes called an elastic S-wave, is one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface waves.
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Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and
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