Optimization And Safety Analysis Of Protective Structure In Inverted Arch Plunge Pool Of Dongzhuang

According to the characteristics of flood discharge and energy dissipation with“high water head,narrow valley and large discharge”,inverted arch plunge pool relies on natural shape of the river bedrock,passes hydraulic load(mainly uplift force) that caused the damage of plunge pool to both sides of the mountain or abutments, giving full play to overloading capacity of arch structure and compression-resistant behaviors of concrete and improving the safety and stability of the protective structure. The practice shows that inverted arch plunge pool is an effective measures to solve the problem of flood discharge and energy dissipation of high dam. In recent years,many scholars at home and abroad carry out many researches on hydrodynamic load and structure stability based on the model test and theoretical analysis,but the optimization study and safety analysis about protective structure of inverted arch plunge pool are few involved. With the background of study on plunge pool of Dongzhuang water conservancy complex project and proceeding from actual engineering,this paper takes static nonlinear optimization analysis of preliminary inverted arch scheme considering multiple factors,and combines mechanics model and numerical model to study safety and stability of protective structure in inverted arch plunge pool. The main research results are as follows:(1)The simulation method for numerical analysis of arch protective structure is improved to make numerical simulation research more realistic,mainly including material nonlinear constitutive damage relationship,the selection of steel bar element considering shear-deformation effects and fluid-structure coupling processing means with contraction joints,etc.(2)Under the design condition of uplift pressure and with stability and integrity as the main weighting indicator,this paper carries out optimization research and determines the radius scheme of 32 m,thickness scheme of 3m and non-uniform flexible anchorage scheme of edge plate with flexible length of 2.5m and middle plate with flexible length of 3m to achieve the purpose of anchorage steel bar and abutment combined to bear loads,and the bearing capacity increases by 30% than uniform rigid anchorage. Impact of bond-slip is negligible for general anchorage mode with free-segment of 2~5m and the same optimization research on slope protective structure.(3)The contact elements with initial gap are used to simulate the arch abutment cracks,and further researches on arching condition and arching action of inverted slab are conducted. Considering pre-stressed anchorage and different uplift pressure level,this paper takes the anti-sliding stability analysis of arch abutment based on rigid equilibrium limit method,concludes that the project can safety and steady operation under 240 kPa uplift load,and study the failure model of inverted arch slab after anchor invalidation in different areas with no coupling damage evaluation method.(4)In line with the principle of “ static design, dynamic adjustment ”,hydrodynamic loads measured by model test is processed as uplift force time history of inverted arch protective structure after optimization and adjustment combining the prediction formula of maximum uplift force,the dynamic response of displacement and stress of protective structure is studied at discharge condition,and the safety assessment is made.