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Dewatering Methods - Groundwater Control

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Groundwater Control When rainwater collects in surface depressions, it is called surface water; when it percolates down into the permeable subsoil and collects in tiny soil voids, it is called groundwater; the upper surface of the groundwater is called the water table. Following some problems of water in the subsoil effect the construction work: A high water table could cause flooding during wet periods. Subsoil water can cause problems during excavation work by its natural tendency to flow into the voids create by the excavation activities. It can cause an unacceptable humidity level around finished buildings and structures. Civil engineers are must restrict the major problems of ground water and keep the excavation to safe. Therefore, they introduce many dewatering methods for controlling the ground water.These methods can be classified into two groups: Permanent exclusion of groundwater Temporary exclusion of groundwater Permanent Exclusion of Groundwater This c...
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Basement Construction

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Basement Construction In the general context of building a basement can be defined as a storey which is below the ground storey and is there for constructed below ground level.  Basements are common in tall buildings as car parks, storage of services and underground shopping centres. The term “basement” has been regarded as synonymous to the term “deep pit”, which applies to excavations over 4.5 m deep. The main purpose of constructing basements are:  to provide additional space,  as a form of buoyancy raft,  in some cases, basements may be needed for reducing net bearing pressure by the removal of the soil. Basement can be classified into three groups: Types of basement Basement can be constructed by following method: Open cut method. Cut and cover method. Top down method. Open Cut Method This is the simplest and most straight forward technique of providing an excavation to the required depth. The sides of the excavation are ...
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Interior Structure of Earth

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Earth’s Profile Our planet Earth has an average radius of 6378 km and a mean mass density of 5.527 g/cm3 compared with a mean mass density of soil particles of 2.7 g/cm3 and water of 1 g/cm3. The earth has a  core  of heavy metals, mostly iron, of mass density 8 g/cm3 surrounded by a mantle. The  mantle  consists of two parts, upper mantle and lower mantle. The upper mantle is solid rock while the lower mantle is molten rock. Above the upper mantle is the  crust , which may be as much as 50 km thick in the continental areas and as little as 7 km thick in oceanic areas. Interior Structure of Earth according to Chemical properties   Crust: The outer most rock layer of the earth is called crust and it is divided into two parts 1.       Continental Crust (0-90 Km) 2.       Oceanic Crust (6-11 Km) Mainly this layer contain Silicon (Si), and Oxygen (O ₂ ) nearly 74% (Silicate-SiO ₂ ) and the tempera...
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