Study On Optimization System Of Highway Slope Prevention Countermeasures And Its Stability Estimation Based On GIS

Recent years, excavation and prevention of slopes along mountainous expressway is given more and more attention. How to efficiently and effectively evaluate the degree of high slope safety and how to make feasible prevention countermeasures are coming to a tough research. Expressway slopes are always the complexity of rockmass and soil, the damage forms of which are so complex and variable that it is very unsure of the slope physical model and its parameters. Although experience and theory is more and more abundant and mature about rockmass mechanics Since 1970. Practice tells that no single method can contain almost all those questions. Mostly, it has to depend on methods of half experience or half theoretics to solve problems from construction practice. Favorable application of basic theory to project is still sometimes in trouble, So it is the necessary task for us to find truth of problems gradually on road construction practice and resolve them constantly.Expressway is always wandering like a piece of belt through mountains and valleys, along which there may be hundreds of slopes. It is such a hard design task that most of slopes in cutting are not directed by precise calculation but experience. Because the mechanics model and accurate dada sometimes behaves so uncomprehendable, while the geological properties so variable by rockmass cutting , that it can not be used in practice. Furthermore, rockmass geological properties are quite sensitive to different design and construction method or quality. Therefore, a good prevention countermeasure always tightly depends on condition in situ. It is very important to make a system to effectively direct the design and construction of road slope. This context brings several points of research as follow:1) To find slide surface is a most important step of slope stability analysis. Slide surface is always of diverse scale and form for complex slope, and in practice, the range of the ahead or rear edges of sliding face on most landslides can often be experientially determined. This context put forward a piece of method to globally search critical slip face on slopes, which may be circle or multi-lines. Given the search area, it can scout around for several dangerous faces in different scopes at one time, and then make sure which to be most dangerous by accurate search.2) Based on work experience in southwest of Zhejiang province, it refers a kind of method of Fuzzy Analysis of Hierarchy Process(AHP-Fuzzy) based on expert experience from slope professors according to characters of highway slopes. It contains 20 factors relating to slope stability, data of which can be taken from GIS conveniently whenever inquiring. Program module has been built in satisfactory use on slopes along the northern Expressway surrounding WenZhou city, which has effectively directed the classification and estimation for slope hazards. So it can validly improve the evaluation efficiency of slope stability.3) Based on the Component Object Model(COM) of ArcGIS, this context has partly developed a piece of relatively compositive system of series of software with differentfunction--HIGHWAY SLOPE OPTIMIZATION SYSTEM( HSOS). It contains moduleof collection, management and maintenance of data, module of 3D simulation, module of calculation methods on half experience or half theoretics(such as AHP-Fuzzy method and Marklands menthod), module of quantificational methods(which includes 2D or 3D limited equilibrium methods, pile and anchor calculation methods and ABAQUS software for finite element analysis) and module of slope hazard prevention countermeasures. HSOS takes powerful management ability to spatial analysis and data maintenance on GIS, it may select module of calculation methods on half experience or half theoretics to judge the degree of stability of hundreds of slopes and put forward corresponding countermeasures for different slopes ordinarily. For special unstable slope, HSOS can bring geometrical model with additional geological parameters conveniently to physical model for stability calculation and make decision to preventive countermeasure. The analysis function of 3D limited equilibrium method and 3D finite element method is offered on HSOS. HSOS is refered to analyze the stability of Hang-Jin-Qu K103 landslide and to optimize the scheme of prevention countermeasures successfully.4) In engineering example of Hang-Jin-Qu K103 landslide, multiple comparative countermeasures and optimized parameters of pile design have been approvingly fulfilled by analysis of 3D simulation of landform, 2D & 3D limited equilibrium analysis, 3D numerical simulation of finite element analysis and landslide monitor data. It gives more theoretical proof for landslide countermeasure analysis.5) According to designing experience of highway slope, it has put forward several kinds of vegetable walls for the safeguard of the foot of high slope. The plan of "Precast soil nail wall-face of cascading flowerpots applied in highway slopes" gained the design patent of China.