Numerical Analysis Of Settlement And Seimsic Response Of Hydropower House On Deep Overburden

Planning in our country will be completed except Tibet Hydraulic and Hydroelectric Engineering, most of the focus will be gradually distract to the Jinsha River, Lancang River, upstream Nu River and the Yalu Tsangpo River Basin in Tibet. The hydropower development in Tibet, less than 6%o compared with the rest of the country. However, South region especially the Yalu Tsangpo River Basin has deep overburden, which is adverse on the development and utilization of groundwater. Therefore, processing of deep overburden has become the key question for hydropower station construction. The giant software of Ansys is applied in my thesis with the rich finite element and the constitutive model of rock. Making use of the Ansys, my thesis mainly studies the changes and value of the deformation modulus after foundation dredging and lording, Combining experimental data to simulate the contacting characteristic of the pile-soil interface, and factors affecting the force distribution and the maximum settlement of pile-soil interface. These studies will be applied to an engineering example in Tibetan areas. The engineering focuses on the hydropower house of ground treatment methods:consolidation grouting and buoyant pile, the different measures under static load how to impact the hydropower house, the deformation and stability of foundation, which has carried on the analysis and evaluation. Foundation treatment has been studied in the following several aspects:(1) Soft soil affects the stability of hydropower plant seriously,the excavation is used to deal with this kind of foundation commonly.The modulus of deformation should not be ignored in the ground treatment.The article selects unload-reload deformation modulus instead of initial deformation modulus,and carries on the numerical analysis combining with D-P yield criterion.(2) Buoyant pile is one of the commonly used methods of deep overburden, but the contacting characteristic of the pile-soil interface is a thorny problem. The influence factors of the interaction between pile and soil was studied by applying contact element to simulate the contact problems between pile and soil in this paper.Results reveal when contact cohesion in the side of pile increases, side resistance of soil around pile increases,and pile-end pressure decreases; contact cohesion in the end of pile increases, side resistance of soil around pile decreases,and pile-end pressure increases.For short pile for the pile diameter,the pile length is more noticeable than the pile diameter in impacting on side resistance of soil around pile, pile-end pressure and structure settlement effect is more noticeable.(3)Under The static and dynamic conditions, consolidation grouting and buoyant pile can control betrer hydropower house settlement and uneven deformation. Variable stiffness design concept is applied:increasing local foundation stiffnes of areas of load concentration, reducing the differential settlement and the workshop and pile foundation slope. Under comparation of the global pile nd the lacal pile in the foundation, the lacal pil can reduce Differential settlement further, at the same time, reduce resources, the construction period and conforms to the economically affordable principle of engineering construction(4) Applied spectrum analysis method to calculate the two-way response of seismic load and and response under the action of water pressure combining with the two-way response of seismic load, the settlement of the hydropower house structure in different working conditions and buoyant pile slope were analyzed. Results show that the consolidation grouting for the influence of friction pile is weak. And the effects of the seismic load resisted by uniform cloth pile and variable stiffness are nearly the same.Research is helpful to the correct application of foundation deformation modulus, the influence of cognitive pile of pile to soil, and increase the running stability of the hydropower plant. Moreover, it can be contributed to planting optimization design and improving the foundation reinforcement measures which are provided the reference for other hydraulic structures on the deep layer.