Design And Research On Drainage System Of Landslide In South Shaanxi Mountainous Area Based On BIM Technology

The mountainous area of Southern Shaanxi is one of the hotspots abundant with dire geological disasters.Among them landslide,which takes a majority of 83%,is a serious impediment to local individual safety and economic growth.We ascribe landside to the level of torrential rainfall in summer and autumn in the mountainous area of Southern Shaanxi,thus a research of the impact of rainfall on landslide steadiness and a drainage system design for the area is significant and necessary.In this thesis the impact of rainfall intensity?duration and slope degree on a landslide was analyzed.With the data provided,we victims proposed a drainage system scenario available for most perspective landslide and visualized the elements within it.Meanwhile we designed a BIM-based model for drainage system elements and built a 3D geological model for simulating the system.By putting the system into practice in Chenjiaying,Mianxian County,we have its drainage system modeling standardized?digitalized and visualized.The major elements and findings are as followed.1)To find the factors that contribute to landslide steadiness with Geo-Studio.Given the rainfall duration and slope degree intact,the mutation level and rate increases with the rainfall on certain spot;and the land's ability to absorb decreases.When it reached it limit,slope streams coalesced,and the safety index decreased.Given the rainfall intensity and slope degree intact,pore water pressure within the penetrated depth increased in line with the law that the pressure of water under table increases in a linear fashion,and the penetrating speed varies in different stages,with the fastest in the top and the slowest in the middle,and the slope foot holds the middle.During the rainfall period the slope safety index decreased markedly in a linear way.Given the rainfall intensity and rainfall duration intact,the water content fluctuates with the rate of slope,whereas pore water pressure and slope safety index do not.2)To compute the correlation coefficient between factors and steadiness with GRA with and the result being:?(D,A)=0.741??(D,B)=0.716??(D,C)=0.910.The descending sequence is slope rate,rainfall duration,rainfall intensity.And we can thus infer that slope rate counts most in a landslide in mountainous areas,for the rate is fixed in given area and cannot be changed.Rainfall duration impact should be more seriously considered in drainage system design.3)We found that around 93% of the slopes are less than 20 cm thick;83% have a angle of 20-40;and 91% of them have a volume smaller than 50×10m.Steady landslide accounts for only 4% of the total number.And we have conducted a principle can be applied into most landslide drainage system in Southern Shaanxi: measures such as annular interception ditch outside the landslide slope body,dendritic interception ditch inside the slope body,tubes for rapid flow and falling energy dissipation pond should be taken into consider;meanwhile we designed intercepting ditch,drainage ditch,rapid trough,water drop and energy dissipation pool suitable for southern mountainous area where landslides are frequent,and proposed the possible structure.4)Digitalized models of rectangular cross-section drainage ditch,trapezoidal cross-section drainage ditch,semi-circular cross-section drainage ditch,rectangular interception ditch,trapezoidal intercept ditch,rapids trough,water drop and energy dissipation pool were established by using BIM parametric modeling software.The BIM family library of each component of the landslide drainage system in the mountainous area of Southern Shaanxi was organized.5)Taking Mianxian's Chenjiaying in Hanzhong City for example.According to the design principles of the landslide drainage system in the southern Shaanxi mountain area,combined with the hydrological rainfall conditions and engineering geological conditions of the Chenjiaying landslide,the cross-section form and layout of the components of the landslide drainage system were designed;The topographic map and drainage system design plan,based on a 1: 1 scale,established its three-dimensional terrain BIM model and landslide drainage system BIM model,and realized the parameterization,information,and visualization of Chenjiaying's landslide drainage system.