| High rock slope stability issue caused by flood discharge atomization of high dam is a major problem which will be faced in the water-power engineering of the west south area of our country. It is related to hydromechanics, quarter-phase fluid mechanics, rock mass mechanics etc, many crossed subjects. In general, there are three difficulty and scientific problems in the research of stability of saturated-unsaturated high rock slope under flood discharge atomization of high dam. First, the rainfall intensity and distribution of flood discharge atomization which is concerned by project can only be estimated by some empirical equations through elementary body observation and physical model tests. The in-depth, systemic quantify analysis is scared. Second, the seepage of flood discharge atomization is a saturated-unsaturated seepage flow course. The research about unsaturated seepage flow in the fracture rock mass is in the initial step, there still exits many problems, such as: the mechanics, the confirmation of hydraulics parameters of rock mass in the unsaturated phase, the choose of mathematics model. Third, the stability of high rock slope under flood discharge atomization. The flood discharge atomization seepage causes the reduction of host suction of rock slope, the increment of temporary water loading, the decrease of rock mass strength, therefore accelerates the slope failure. But the achievements of quantify research this problem is in shortage. The research work in this dissertation is about the rock slope stability issue caused by flood discharge atomization of high dam, based on the three problems above, selecting the spandrel groove slope of flood discharge atomization area in Gou Pitan right bank as the research background.The main research work in this dissertation is focused on the following: 1, Limited by the deficiency of rainfall intensity and distribution of flood discharge atomization and the fuzziness of our understanding, the rainfall intensity and distribution of flood discharge atomization is researched by fuzzy mathematics, and influence factor of flood discharge atomization is analyzed, the fuzzy mathematics model is established. In order to reduce the subjective influence of man-made factor, one method of determining the membership function is found, that is constitute the membership function on the basis of statistical analysis, then forecast the rainfallintensity and range by the fuzzy comprehensive judge (the max degree of membership rule).2, Choose the spandrel groove slope in Gou Pitan right bank as the research background, and divide the engineering geology petrofabric of slope mountain on the basis of familiar with the slope rock character, rock mass structure, constitution, deformation and strength of rock mass. The rock mass character of slope off-load area is major researched, and the nature slope is divided to five engineering geology area based on the slope type, rock character and constitution, carst development character, off-load character, and influence degree of flood discharge atomization. According to the slope surface information, excavation information, rock formation information, draining hole and purdah information, the three dimensional grid generated by self-programming is used to generate the compute geology model, and provide the basis for the analysis of seepage flow field and stress field of slope. The model created by this method saves the basic mountain information, making full use of control information in the slope and reflecting the original slope feature and slope shape after excavation when the grid scale is certain, avoiding the distortion in the model building process caused by simplify incorrectly.3 , Based on the plenty of field measured fracture data, the statistical analysis about fracture density, azimuth, size, continuity, jaw opening is carried out, the random model of discrete fracture network is established on Enhanced Baecher model. The Monte Carlo random simulation is used in fracture network random simulation, thus the three-dimensional discrete fracture network figure of different dimension is got. According to the figure, the validity analysis of equivalent continue mediator model for slope seepage field is carried and seepage tensor is computed on the basis of statistical geometry data, providing important hydraulic parameter for seepage field analysis.4 , The movement character of slope water and the factor influencing the seepage under the flood discharge atomization and rainfall seepage condition is researched. According to the control equation of saturated-unsaturated state, the integral saturated-unsaturated unsteady seepage control equation is constituted on the connection of saturation degree. The FEM computation format of mathematic model is deduced by Galerkin weighing margin method, the compute iterate mode of nonlinear FEM is developed, and the three dimensional FEM program USSEEPAGE3D of computing saturated-unsaturated unsteady seepage under ground seepage condition by FORTRAN language. This program includes fore treatment part, main computeprogram part and post treatment part, and each part has definite function meaning, can handle the complexity of practical matter and is flexible. The unsaturated hydraulic parameter problem and initial water head field problem in the FEM solve is treated, thus the solve equation is in high efficiency, fast convergence and stationary. Based on the programmed and technique method in the course of FEM computation to simulate the seepage field under flood discharge atomization of slope in Gou Pitan hydroelectric station right bank, and the result can be provided an important reference for slope rock mass seepage control.5, The mechanics of slope failure due to atomization seepage is profound researched. Through the relation between seepage characters of fracture rock mass and stress, elastic-plastic constitutive equation of fracture rock mass and control equation of seepage field, the equivalent continue mediator model of seepage and stress field coupling is established. The two-field coupling is solved by iteration. The stability of slope is evaluated by FEM, which is used a lot in the slope stability analysis at present. In the end, for the example of flood discharge atomization region slope of Gou Pitan right bank, the component of slope rock mass under the coupling action and not including the influence of seepage field is computed, and the stability of slope is analyzed. At the same time, the influence of different seepage control measures is discussed, and the result can be provided an important science gist for safety estimate in practical project.
|
PDF Full Text Request