Seepage Simulation And Stability Analysis Of Ash Field Under Rainfall Condition

The ash storage yard is an important part of coal-fired power plants.It is responsible for the storage of coal-fired ash slag.It is a man-made dangerous source with high potential energy.Its stability is related to the lives and properties of the people and the ecological environment.In many ash yard accidents,heavy rain or continuous rainfall is an important cause of dam deformation or even dam collapse.In this paper,the Wawagou valley ash storage yard is taken as the research object,and the actual field investigation,indoor experiment combined with theoretical analysis and numerical simulation research methods are used to stabilize the unsaturated seepage field and the ash storage dam under storm conditions and continuous rainfall conditions.Systematic research was conducted to analyze the distribution of seepage field of ash storage sites under different rainfall conditions,and on this basis,the stability of ash storage dams was analyzed,and the main factors and combinations that affected the stability of dams were obtained.The following main results have been obtained:(1)The fly ash contained in the ash dam can be divided into three layers through on-site dynamic testing: The first layer of slightly dense fly ash is mainly distributed in the upper part of the sub dam,with a depth of 1.9-2.7 m;the main distribution of dense fly ash in the second layer In the vicinity of the right abutment,the depth is 3.6~7.2m;three layers of dense fly ash are mainly distributed in the bottom of the dam.(2)In rainstorm intensity of 68mm/h and rainstorm lasts for 6 hours,the rainfall intensity is greater than the infiltration capacity of the soil.The surface of the ash field will form a temporary saturated zone and generate surface runoff.The depth of rainwater infiltration is affected by rainfall intensity.The influence is relatively small,and the infiltration depth increases nonlinearly with the increase of the permeability coefficient under this working condition;In the case of continuous rainfall with a rainfall intensity of 3.4 mm/h and continuous rainfall of 120 hours,the rainfall intensity is lower than the infiltration capacity of the ash field.Rainwater will infiltrate directly into the ash field,and the depth of infiltration will be deep.Under these conditions,The seepage depth increases linearly with the increase of the permeability coefficient.(3)Under rainfall conditions,the total displacement of the ash storage dam increases with the increase of rainfall time,and the safety factor decreases with the increase of the ash permeability coefficient,ash storage dam stability is reduced.The longer the rainfall,the lower the safety factor of the ash storage dam,the poor stability of the ash storage dam.It can be seen that the safety factor decreases with the increase of the permeability coefficient into the quadratic terms through the fitted curve of the safety factor with the change of the ash field permeability coefficient under two different rainfall conditions.The ash yard has the lowest safety factor under long-term water conditions.The ash dam is the most dangerous under long-term water conditions,ash storage dam is the worst.So the long-term accumulation of water should be avoided in the operation and management of the ash yard.