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Revetment
A revetment in stream restoration, river engineering or coastal engineering is a facing of impact-resistant material (such as stone, concrete, sandbags, or wooden piles) applied to a bank or wall in order to absorb the energy of incoming water and protect it from erosion. River or coastal revetments are usually built to preserve the existing uses of the shoreline and to protect the slope. In architecture generally, it means a retaining wall. In military engineering it is a structure formed to secure an area from artillery, bombing, or stored explosives. Freshwater revetments Many revetments are used to line the banks of freshwater rivers, lakes, and man-made reservoirs, especially to prevent damage during periods of floods or heavy seasonal rains (see riprap). Many materials may be used: wooden piles, loose-piled boulders or concrete shapes, or more solid banks. Concrete revetments are the most common type of infrastructure used to control the Mississippi River. More than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Revetment
Dynamic revetments, also known as "cobble berms" or "dynamic cobble berm revetments", use gravel or Cobble (geology), cobble-sized rocks to mimic a natural cobble storm beach for the purpose of reducing wave energy and stopping or slowing coastal erosion. Unlike seawalls, dynamic revetment is designed to allow wave action to rearrange the stones into an equilibrium profile, disrupting wave action and dissipating wave energy as the cobbles move. This can reduce the Reflection (physics), wave reflection which often contributes to Hydrodynamic scour, beach scouring. Principle The goal is to create structures that are natural in appearance and function while providing acceptable protection to coastlines, combining the benefits of ecologically responsive shore protection methods with those of conventional armor‑stone revetments or seawalls. A line of logs can also be employed as upper reinforcement for a cobble berm. Drift logs are common on most shores in the Pacific Northwest. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retaining Wall
Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to (typically a steep, near-vertical or vertical slope). They are used to bound soils between two different elevations often in areas of inconveniently steep terrain in areas where the landscape needs to be shaped severely and engineered for more specific purposes like hillside farming or roadway overpasses. A retaining wall that retains soil on the backside and water on the frontside is called a seawall or a bulkhead. Definition A retaining wall is designed to hold in place a mass of earth or the like, such as the edge of a terrace or excavation. The structure is constructed to resist the lateral pressure of soil when there is a desired change in ground elevation that exceeds the angle of repose of the soil. A basement wall is thus one k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liliw, Laguna
Liliw, officially the Municipality of Liliw (), is a municipality in the province of Laguna, Philippines. According to the 2020 census, it has a population of 39,491 people. Liliw is perhaps best known for its cold water spring resorts, native homemade sweets and a sizeable shoe industry that rivals that of Marikina. The town is also known for its baroque church and its Liliw-style houses. The local government is currently undertaking means to conserve its cultural heritage sites and has proposed to enact a legislation that would mandate the usage of the Liliw-style architecture as the only means of construction and re-construction in the town. If the ordinance passes, Liliw will have a greater chance to become a heritage town, and further support from the National Commission for Culture and the Arts. History Founded in 1571 by Gat Tayaw, the small town of Liliw is nestled at the foot of Mount Banahaw, away from Santa Cruz, Laguna's capital. According to a story, Liliw go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Civil War
The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of America, Confederacy ("the South"), which was formed in 1861 by U.S. state, states that had Secession in the United States, seceded from the Union. The Origins of the American Civil War, central conflict leading to war was a dispute over whether Slavery in the United States, slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction. Timeline of events leading to the American Civil War, Decades of controversy over slavery came to a head when Abraham Lincoln, who opposed slavery's expansion, won the 1860 presidential election. Seven Southern slave states responded to Lincoln's victory by seceding f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Park Service
The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List of national parks of the United States, national parks; most National monument (United States), national monuments; and other natural, historical, and recreational properties, with various title designations. The United States Congress created the agency on August 25, 1916, through the National Park Service Organic Act. Its headquarters is in Washington, D.C., within the main headquarters of the Department of the Interior. The NPS employs about 20,000 people in units covering over in List of states and territories of the United States, all 50 states, the District of Columbia, and Territories of the United States, US territories. In 2019, the service had more than 279,000 volunteers. The agency is charged with preserving the ecological a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trench Construction Diagram 1914
A trench is a type of excavation or depression in the ground that is generally deeper than it is wide (as opposed to a swale or a bar ditch), and narrow compared with its length (as opposed to a simple hole or pit). In geology, trenches result from erosion by rivers or by geological movement of tectonic plates. In civil engineering, trenches are often created to install underground utilities such as gas, water, power and communication lines. In construction, trenches are dug for foundations of buildings, retaining walls and dams, and for cut-and-cover construction of tunnels. In archaeology, the "trench method" is used for searching and excavating ancient ruins or to dig into strata of sedimented material. In geotechnical engineering, trench investigations locate faults and investigate deep soil properties. In trench warfare, soldiers occupy trenches to protect them against weapons fire and artillery. Trenches are dug using manual tools such as shovel and pickaxe or heavy eq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breakwater (structure)
A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Breakwaters have been built since antiquity to protect anchorage (maritime), anchorages, helping isolate vessels from marine hazards such as wind-driven waves. A breakwater, also known in some contexts as a jetty or a Mole_(architecture), mole, may be connected to land or freestanding, and may contain a walkway or road for vehicle access. Part of a coastal management system, breakwaters are installed parallel to the shore to minimize erosion. On beaches where longshore drift threatens the erosion of beach material, smaller structures on the beach may be installed, usually perpendicular to the water's edge. Their action on waves and current is intended to slow the longshore drift and discourage mobilisation of beach material. In this usage they are more usually referred to as groynes. Purposes Breakwaters reduce the intensity of wave action in ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactured material in the world. When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that can be poured and molded into shape. The cement reacts with the water through a process called hydration, which hardens it after several hours to form a solid matrix that binds the materials together into a durable stone-like material with various uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process is exothermic, which means that ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodynamic Scour
lang=en, upright=1.3, Mechanism of formation, alt=sketch Hydrodynamic scour is the removal of sediment such as silt, sand and gravel from around the base of obstructions to the flow in the sea, rivers and canals. Scour, caused by fast flowing water, can carve out scour holes, compromising the integrity of a structure. It is an interaction between the hydrodynamics and the geotechnical properties of the substrate. It is a notable cause of bridge failure and a problem with most marine structures supported by the seabed in areas of significant tidal and ocean current. It can also affect biological ecosystems and heritage assets. Mechanism Any obstruction within flowing water will produce changes in velocity within the water column. The flow changes that occur in the vicinity of the substrate may cause differential movement in the bed materials near the obstruction. The magnitude of these changes varies with stream velocity, feature shape and substrate character. Generally the str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storm Beach
A storm beach is a beach affected by particularly fierce wind wave, waves, usually with a very long fetch (geography), fetch. The resultant landform is often a very steep beach (up to 45°) composed of rounded Cobble (geology), cobbles, shingle beach, shingle and occasionally sand. The stones usually have an obvious Grade (slope), grading of pebbles, from large to small, with the larger diameter stones typically arrayed at the highest beach elevations. It may also contain many small parts of shipwrecked boats. Examples A noted textbook example is the long Chesil Beach in Dorset, one of three major shingle structures in Britain. It also connects the Isle of Portland to the mainland at Abbotsbury, west of the resort of Weymouth, Dorset, Weymouth. Other examples appear in the Shetland Islands, Shetland and Orkney Islands, as well as the Scotland, Scottish mainland at Caithness. The beaches of Lakshdweep Islands are also storm beaches. Gallery File:Storm Beach - geograph.org.uk - ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
