| Landslide is one of the common natural disasters in the world. It reaches more than half of the total case number of all kinds of natural disasters each year. It not only brings threat to the human life, but also causes serious damage to the environment, resources and property. The evaluation of landslide stability, the prediction for the development trend and the endangered area are the core work of the landslide disaster prediction.Due to the complexity of landslide formation mechanism, the variety of inducing factors and high overhead expenses, the present measures are monitoring on a large scale and continuous deformation of the landslide. Traditional landslide stability evaluation is mainly from the perspective of mechanics, such as using the mechanical constitutive model to evaluate landslide stability safety factor. However, the most direct data obtained by landslide monitoring is generally the surface displacement and deep displacement. The current research usually by fitting and infer mathematical method to analyze the deformation characteristics of the landslide. These studies did not fully dig the relationship between monitoring data and inside the landslide failure characteristics.Based on the simulated data, this paper establishes the relationship model between landslide deformation and internal failure characteristics. It will realize the research purposes which can directly evaluate the landslide stability status and development trend by using displacement characteristics. It can provide a convenient and efficient way for landslide prediction. At the same time, this paper studyes the motion sliding process of landslide instability and establishes the sliding model based on GIS and the mechanics model.This thesis has developed the creep landslide deformation instability characteristics and instability of sliding simulation study from three aspects of theoretical model research, experimental verification and case analysis. Using the finite element strength subtraction and by means of FLAC3D, the paper mainly studies the relationship between the surface displacement and safety factor in the whole process of creep landslide occurrence and development to destroy and damage, and then, establishes the characteristics of deformation and internal relation model of creep landslide. With the indoor landslide experimental research and the three landslide experimental research of Qianjiangping landslide, Liangshuijing landslide and Jinpingzi landslide, we validate the characteristics of deformation and internal relation model of creep landslide proposed in this paper. On the basis of the thesis proposed relationship model, stage of landslide stability criterion based on the apparent displacement mutation point has been established. Comparing to the analysis of the actual monitoring data of jinpingzi landslide's zone II and Outang landslide, it obtains good results. The paper completes the creep landslide deformation instability characteristics of the research and practice. On the basis of the study, we study the slide instability of creep landslide movement simulation. The smooth particle hydrodynamics (SPH) three-dimensional particle model based on GIS and mechanical model has been proposed. Taking Tangjiashan landslide and Jinpingzi landslide's area II as examples, this paper respectively verifies and analyzes the model. The paper completes the instability of creep landslide sliding simulation research and practice. The paper work and the main conclusions are as follows:1?Summarizing the research methods and the present situation of the landslide stability evaluation, forecast and influence range forecast. According to the characteristics of the creep landslide, this paper puts forward the research target that uses the creep landslide surface displacement to define the standard of the evolution stage of the landslide.2?Based on displacement characteristics, the paper puts forward the characteristics of deformation and internal relation model of creep landslide. It systematically summarizes the creep landslide deformation-time curve features and basic principle, the determination of sliding surface, failure criterion and constitutive model, yield criterion and application status of strength subtraction. How to select strength subtraction failure criterion is studied in this paper. The FLAC3D is adopted to do numerical simulation of the homogeneous slope. According to the simulation data of surface displacement, we analyze the surface displacement and reduction factor curve, and then we get creep landslide deformation characteristics of surface displacement in the process of evolution: there are two obvious mutation points on the surface displacement and reduction factor curve. The two mutations points respectively corresponding safety factor value are defined as a and b. The landslide evolution process is divided into three stages based on this line:when the safety factor is greater than or equal to a, landslide at the stable stage; when the safety factor is more than b and less than a, landslide at the destruction stage; when the safety factor is less than or equal to b, landslide at the stage of instability. Secondly, based on the simulation of principal stress analysis of slip, we get that the principal stress won't appear obvious change when the safety coefficient is to reduce.3. This paper carries out the experimental study on the characteristics of deformation and internal relation model of creep landslide. The experiment is mainly divided into two parts:(1) Determining the landslide model material parameters. The density, cohesive force and angle of internal friction are obtained by soil mechanics test. (2) Analyzing the surface deformation characteristics of the landslide model. We use the ground type three-dimensional (3D) laser scanner to monitor surface displacement in the whole process of landslide model from initiation to failure. Through DEM comparison method, we get the landslide deformation displacement in the vertical direction and analyze the characteristics of the landslide deformation displacement in the entire process from the occurrence and development to destroy:there are two obvious mutation points on the surface displacement and safety factor curve, and displacement value presents obvious increasing trend according to the mutation point line. This shows that the landslide internal state has changed in the event of a mutation point of time and there is a close link between the surface displacement and internal state. At the same time, we record the landslide trailing edge crack development situation to assist the landslide stability evaluation.4?In the case of Qianjiangping landslide, Liangshuijing landslide and Jinpingzi landslide, this paper has carried on the case study on creep landslide deformation instability evaluation. The paper uses strength subtraction for instance analysis research on the basis of the landslide instance field geological survey data. The FLAC3D is adopted to do numerical simulation of the three landslides. According to the simulation data of surface displacement, we analyze the surface displacement and safety factor (reduction factor) curve and we get that there are two mutation points on the surface displacement and safety factor (reduction factor) curve in the whole process of creep landslide occurrence and development to destroy and damage. Research shows that through the displacement mutation point to evaluate the stability of landslide is feasible. And then, we analyze the maximum and minimum principal stress data. We find that the principal stress did not show significant changes. Therefore, by monitoring the stress changes to analyze the creep landslide stability is not obvious effective.5?Based on the proposed characteristics of deformation and internal relation model of creep landslide in this paper, landslide stability criterion is established based on the apparent displacement mutation points a and b. In the case of jinpingzi landslide and Outang landslide, first of all, this paper makes statistics and analysis of jinpingzi landslide's surface displacement monitoring data from May 18,2005 to September 25,2009 and deep displacement of borehole inclinometer data in the effective observation period of time. At the same time, we use the establishment stage of landslide stability criterion to get the internal failure characteristics and the situation of stability. The results obtained from the criterion are in line with results obtained through the practical field monitoring data analysis. And then, this paper makes statistics and analysis of Outang landslide's surface horizontal displacement monitoring data from February 1,2014 to January 31 2015 and gets its deformation characteristics. At the same time, we use the establishment stage of landslide stability criterion to get the internal failure characteristics and the present situation of stability. The results obtained from the criterion are in line with results obtained through the practical field monitoring data analysis.6?Based on GIS and the mechanics model, the paper proposes the creep landslide sliding simulated SPH three-dimensional particle model. First of all, the paper systematically studies the slope information expression of GIS and makes the space of the landslide related information can be expressed in the form of GIS data, such as ground surface, strata, sliding surface, underground water level, etc. Then, the paper studies the landslide sliding simulation of SPH method and mechanics model based on the Bingham fluid. On the basis of the study, the landslide SPH three-dimensional particle model based on GIS spatial data and Bingham fluid constitutive model has been established. And the paper realizes the insert filling process of particles through the C# programming, which improves the efficiency of the simulation. Further, by combining Moore-coulomb failure criterion of SPH as the core, the paper has realized the instability of creep landslide motion process simulation.7?Taking Tangjiashan landslide and Jinpingzi landslide's area ? as examples, we do the case study of the motion simulation of the landslide instability. Using the proposed creep landslide SPH three-dimensional particle model to establish the Tangjiashan landslide 3D section SPH particle model, combined with Moore-coulomb failure criterion of SPH as the core, the Tangjiashan landslide three-dimensional SPH simulation results are obtained. And compared with the existing two-dimension SPH simulation results, Studies have shown that 3D SPH simulation is closer to real condition than the two-dimension SPH simulation and verifies reliability and superiority of the proposed creep landslide sliding simulated SPH 3D particle model. Secondly, regarding Jinpingzi landslide's area ? as the object, the paper simulates the movement of the instability of the whole process and forecasts the influence of the landslide instability. |
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