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Definition and classification of ground fissures

2019-12-05  |   Editor : houguangbing  

The ground fissure is the abbreviation of the ground crack. It is a linear fracture phenomenon in surface rock and soil. The influencing factors are: surface rock.The layer and soil are affected by natural factors (crustal activity, water effect, etc.) or human factors (pumping, irrigation, excavation, etc.). Ground fissure can be groundOne of the precursory phenomena of earthquake, or the residual deformation of the earthquake on the ground. The latter is also known as an earthquake crack.

There are few studies on the types of ground fissures abroad, mainly the research and analysis of the dynamic causes of ground fissures. It is the internal and external power of the earth's crust. It can be divided into three main types: structural genetic ground fissure, groundwater mining cause, ground fissure, and tectonic and groundwater exploitation. Domestic researchers have carried out a complex but meticulous classification of domestic cracks. Some scholars regard ground cracks as internal force cracks and natural crevices, some are divided into internal forces caused by ground fissures, external forces caused by ground fissure and human engineering economic activity causes and ground fissures; some are divided into human beings. There are two major categories of active ground cracks and natural factors. In human activities, there are two types of cracks in the mining subsidence and the deformation ground cracks in the buildings. Under natural factors, they are subdivided into two types of fractures, such as fractured tectonic ground cracks, tilting structures or rising tectonic zones, which are divided into a dry ground crack and a structural expansion under the latter. There are five types of ground cracks, and some are divided into two types: tectonic ground fissures and non tectonic fractures, in which the tectonic ground cracks are dominated by natural internal force, the dynamic type is fault movement and regional micro fracture opening, and the non tectonic movement is subdivided into the ground fissure dominated by human activity and the natural external force as the leading ground fissure.

According to the causes of ground fissures, they are often classified into the following categories:

1) Earthquake cracks are caused by strong vibrations on the ground caused by various earthquakes.

2) The basement fracture activity cracks are due to the long-term peristaltic movement of the basement fracture, which gradually cracks the rock mass or soil layer and forms on the surface.

3) The open cracks in the hidden fissures are the soils with insidious cracks. Under the action of surface water or groundwater scouring and submarine erosion, the materials in the fissures are carried away by water, and the fissures are opened upward and penetrated.

4) Leakage cracks in loose soils are due to erosion, subsurface erosion, softening, and liquefaction of surface water or groundwater, which cause some particles in loose soil to be lost with water, and the soil body is cracked.

5) Loess wet-fall cracks are caused by subsidence due to the soaking of surface water or groundwater in the loess layer.

6) Swelling and contraction cracks are due to the dry and wet climate changes that cause swelling and shrinkage deformation of expansive soil or silty soft soil.

7) Ground subsidence cracks are caused by rock and soil cracking during land subsidence caused by ground subsidence or overexploitation of groundwater and underground mining of mines.

8)Landslide cracks are caused by surface cracking caused by slope sliding.

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