A Contrastive Study On Numerical Simulation Of Landslide Deformation And Failure In Different Dimensions

At present,the numerical simulation is one of the main methods to study the deformation and failure of landslide.According to the different spatial dimensions,the numerical simulation can be divided into three parts: the two-dimensional simulation,the quasi three dimensional simulation and the three-dimensional simulation.In this paper,the author take Leijiaping landslide in Three Gorges Reservoir area as an example to carry out two-dimensional,quasi three dimensional and three-dimensional numerical simulation of landslide deformation under the condition of reservoir water level fluctuation.Then analyze and compare the results to reach the applicable conditions of numerical simulation in different dimensions.The conclusions are as follows:(1)There is no evidence of large scale and local deformation at the present stage.But the bank of reservoir water level has fallen.Monitoring data show that there are slight deformation on the surface of the landslide,which mainly occurs at the stage of reservoir water level decline.(2)When the water level ishigh as 175 meters or reservoir water level decrease,the displacement at the leading edge of Leijiaping landslide is larger.At other times,the displacement in the middle of landslide is larger.The maximum displacement in three-dimensional simulationis located at the middle of the landslide under different conditions.Since the actual topography of landslide is reflected,the displacement values obtained by 3D simulation are larger than those of other dimensions.(3)The plastic zone of Leijiaping landslide in two dimensional simulation are mainly developd in the middle of the landslide.When water level is 175 meters high or drawdown the landslide area of plastic zone is larger.The plastic zone of Leijiaping landslide in quasi three dimensional simulation are mainly developd in front of the landslide.When water level drawdown the landslide area of plastic zone is larger.The plastic zone of Leijiaping landslide in three dimensional simulation are mainly developd in front of the landslide.When water level is 175 meters high or rising,the landslide area of plastic zone is larger.(4)The stability calculation results of Leijiaping landslide show that variation of landslide stability in different dimensions is consistent.The landslide stability is slightly better when reservoir water level is 175 meters.When the reservoir water level drops,the landslide stability becomes worse.If the decrease rate turns faster,the stability turns more worse.When the reservoir water level rises,the landslide stability becomes better.And the stability are better when it rises faster.When water level decrease at the speed of 2.0 meter everyday,the stability of landslide is worst.The relative stability relative to 145 meters reservoir decreased by 8.2%,9.1% and 12.3% respectively.(5)Two dimensional simulation and quasi three-dimensional simulation require less data.The model establishment and calculation process is simple.But the result is not reliable,there are big errors.Three dimensional simulation requires sufficient data to do so.The model establishment and calculation process are complex.But the calculation result is more practical and the error is smaller.(6)Two-dimensional or quasi three dimensional simulation should be adopted if the terrain condition is complex.The results of two-dimensional simulation are more serious and less stable.It is safer in landslide control project.The results of quasi three dimensional simulation are more consistent with the actual results.It saves the budget of landslide prevention and control project.(7)When the terrain condition is simple,three-dimensional simulation should be selected.Because the three-dimensional simulation results are closest to the actual results and the fluctuation of reservoir water level is most obvious.The results of three-dimensional simulation show that the deformation is relatively minimum and the stability is the best.In numerical simulation,the maximum amount of unnecessary engineering budget is saved.