Tension Crack Of Loess Tableland Edge Extension Mechanism And Effect Of Landslide Research

Loess tableland edge region development have bad geological phenomenon such as landslide,collapse,which is given priority to with landslides.After a great deal of case study we have recognized that the loess tableland edge tension crack opening and extension is one of the crucial factor for the formation of the loess tableland edge of landslide.Tension crack open is the starting point of landslide formation,tension crack extension and import role of water is the main external agent landslide formation.But there are several key problems has not been well solved,first of all,the loess tableland edge tension crack opening and extension mechanism is what?How much is the effective depth of the tensile fracture?Secondly,tension crack guide water which influence on landslide stability?Finally,the surface water through tensile crack quickly into the slope under the condition of the formation mechanism of landslide is what?This paper through physical model tests and indoor loess tensile strength test,tensile stress in the simulation environment,when the moisture content increases,the loess loess tableland boundary tension crack opening and extension mechanism and crack depth effect on the stability of the landslide,and then using the method of numerical simulation and theoretical analysis,the softening action of water and instantaneous high head coupling effect influence on the landslide stability.Finally based on the above two aspects,analysis of the loess tableland edge start the mechanism of landslide.The results for the loess tableland edge provide theoretical basis for the stability evaluation and forecast landslide.In this paper,the main conclusions are as follows:(1)the emergence of the tensile fracture is due to the tensile stress in the body than the loess slope,tensile strength and the tensile strength of loess are negatively related to its moisture content,and decreased with the increase of soil moisture content,which is under the condition of rainfall the slope trailing edge is more prone to the cause of the crack and crack expanding.Tension cracks and the distance between the tableland edge and the depth of fissures of different has the different effect on the stability of the landslide.(2)the tensile crack guide role for the formation of the landslide water plays an important role,it provides effective channels for surface water directly into the slope,the underground water level rise,increased the degree of sliding body weight and slope of the pore water pressure in the body,effectively through sliding surface,reduce the shearing strength of the sliding body,at the same time as the cracks in the height of water increases,landslide instability increase trend.(3)the formation of the loess tableland edge of landslide,first of all depends on the degree of erosion slope foot,when a steeper slope erosion,the tensile strength of loess is lower than the tensile stress in the slope body,tension crack will open;Secondly,tension crack extension downward,resulting in the range of the slope body shear stress area,shear stress concentration;Third,the surface water along the tension crack down into,when the top tension crack,shear failure area in central slope and slope toe static liquefaction area through later,was formed a continuous sliding surface,formation of landslides.