The Study Of The Landslide Monitoring Network Reconstruction Within Unified Datum In The Three Gorges Reservoir Area And Its Application

This study introduced the establishment and application of the landslide monitoring network in the Three Gorges Reservoir Area. The purpose of this thesis is to conduct a systematic review of the current theories, methods and results on GNSS reference frame, high-precision GPS data processing and deformation analysis, GPS deformation monitoring network optimization design, etc. Based on the compiled data, an in-depth research and analysis was conducted to:1. The reference datum of the Three Gorges Reservoir Area landslide monitoring and its transformation.This includes:●Definition, establishment and maintenance of International Terrestrial Reference Frame.●Reference system of the Three Gorges Reservoir Area landslide monitoring network.●Transformation of different periods of ITRF.●Datum unification of precise ephemeris and ground-based reference station in high-precision GPS measurement.●Transformation of WGS-84reference system and national reference system (1954Beijing coordinate system or1980Xian coordinate system in China).2. The systematic study of the data processing theory and methods of GPS monitoring network.This includes:●Systematic error analysis and processing in the high-precision GPS data processing.●Establishment and solution of relative positioning model.●GPS free network adjustment model.●Outlier analysis in GPS baseline network.●Systematic error analysis and processing in GPS baseline network.●Datum unification of multiple observation period GPS monitoring network.3. The study of the landslide monitoring network Reconstruction within Unified Datum in the Three Gorges Reservoir Area.For the special geographical location and complex terrain conditions in the Three Gorges Reservoir Area, the following areas of interest were evaluated:●GPS observation plan.●High-precision GPS data processing programs.●For the different GPS observations, an analysis on the influence on the adjustment results by the systematic error of time evolution datum, and propose iterative adjustment method to eliminate the impact of the systematic error.●The method of GPS baseline network adjustment and datum unification with the Three Gorges Reservoir Area landslide monitoring network established in2005.●Obtain the new monitoring points of122landslides into the landslide monitoring network, with the unified datum, establish the deformation judgment standard for all the points, solve the technical problem in the work of the Three Gorges Reservoir Area landslide monitoring.4. The landslide monitoring datum stability analysis in the Three Gorges Reservoir Area. This includes:●To address the issue of landslide monitoring along the600km long Three Gorges Reservoir Area, a study of landslide monitoring datum stability analysis method, which takes into account the impact of plate movement in the large-scale deformation analysis was performed.●This analysis was done with historical GPS observations data (2008-2011a) of landslide monitoring network, the stability of all reference points was tested:The results indicate there was existence of the moved reference points in this three years of high water environment. The displacement direction of unstable reference points was inspected with the geographical environment at sites, showing they were consistent.5. The landslide monitoring network optimization design in the Three Gorges Reservoir Area. This includes:●Determination of the quality indicators of accuracy, reliability, sensitivity and cost in the GPS landslide monitoring network. Establishing of the GPS landslide monitoring network optimization model and the interactive approach and analytical method used in the GPS landslide monitoring network optimization.●Under the complex GPS observation conditions of the Three Gorges Reservoir Area, obtain the best GPS observation and solution plan, the better graph structure of GPS landslide deformation monitoring network.●For the work of landslide monitoring in the Three Gorges Reservoir Area, summed applicability conclusion.