Study On Uplift Deformation Of Gravity Dam Foundation And The Mountains Near Dam Under Specific Geological Conditions

In the domestic and international water conservancy and hydropower projects,the dam foundation and the mountains near dam uplift deformation phenomenon is relatively rare.How to analyze the formation mechanism of uplift deformation and evaluate the impact of uplift deformation on engineering safety has become a new research topic.Based on the analysis of domestic and foreign literatures and the theoretical study of uplift deformation,the special geological structure model and the influence of rock mass characteristic parameters on the uplift deformation are studied by means of numerical simulation.And the practical problems of the uplift deformation of the mountains near left bank of XiangJiaba are discussed in depth.The research results have certain reference value for the evaluation of the safety of the uplift deformation of the water conservancy project.The main research results are as follows:1.Combined with domestic and foreign literature research,proposed to induce the dam foundation and the mountains near dam uplift deformation of the hydrogeological structure model,that is,the dam site tends to downstream or cross-strait relative to the aquifer,and relative to the aquifer with the upper reaches of the reservoir relative permeability Larger geological structure layer(aquifer).2.The numerical simulation of rock mass expansion mechanism shows that the pore water pressure,permeability coefficient and deformation modulus of rock mass have a great influence on the expansion of rock mass.The initial stress has a weak influence on rock mass expansion.3.Using numerical means to analyze the research plan of different hydrogeological structures.The results show that the closer to the dam at the bottom of the reservoir is closer to the dam,and the higher the deformation value of the downstream dam near the dam.The higher the dam foundation is inclined with the inclination of the dam foundation,The distance of the uplift deformation is more and more close to the dam.When the inclination angle of the aquifer is constant,the change of the inclination is directly affected by the location and the range of the uplift deformation of the dam foundation and the mountains near dam.4.The different effects of deformation modulus and permeability coefficient on the uplift deformation of different rock mass are studied.The results show that the deformation is more sensitive to the deformation modulus,the larger the deformation modulus,the smaller the lift displacement and its range.The change of the permeability coefficient of the aquifer is more sensitive than the aquifer.5.Based on the monitoring results of the mountains near dam on the left bank of XiangJiaba,the process of uplift deformation of the mountains near dam on the left bank is studied.The results show that the uplift deformation of the mountains near dam on the left bank is the result of the accumulation and deformation of the internal rock mass under the action of osmotic pressure.The crushing zone on the left bank near the dam has played a blocking role in seepage and provided the required geological conditions for uplift deformation And the drainage hole arranged on the left bank near the dam body can effectively reduce the pore water pressure of the lower rock mass in the crushing zone.The uplift deformation may lead to the local landslide of the dam body and the possible failure of the dam foundation.