| The spillway tunnel of dam have the function of releasing flood waters with the spillway, sediment flushing and construction diversion. Due to the spillway tunnel and corridors,the dam will be partially weaken for the stress concentration.It need high demandingness of reinforcement. Accurate stress analysis is the foundation of the dam design. We often calculate stress by the material mechanics method, for its simplicity and wide usage. This way is not applicable to some special problems, such as stress concentration. At present, numerical simulation is widely employed in the field of engineering technology study. ANSYS software have broad application prospects in engineering checking, simulation, etc.In this thesis, the finite element model of Qingyu reservoir spillway section is built by ANSYS software which owns powerful preprocessor and postprocessor function. It can simulate the true transformation process about the spillway tunnel’s displacement and stress. It is propitious to the study of dam’s intensity. The stress of Spillway deflected side of the axis is asymmetric distribution. With the three dimensional FEA model of ANSYS software we can get a more accurate result of stress distribution, which can be targeted to improve the safety and reliability of spillway tunnel. It also can provide the basis of reinforcement and reference value of similar problems for other project.We can get those following results With the nonlinear ideal elastoplastic Finite Element model:1、The dam without water,have displacement only in the vertical direction. The maximum displacement appears in the top of the dam by the upstream face.With design water level, the dam tilt to the downstream. The crest displacement is greater than the dam base.2、The concrete of the dam without water meet the requirements of tensile strength and compressive strength. The maximum tensile stress value is0.58MPa, in the bottom of the spillway tunnel entrance, the maximum compressive stress is2.46MPa,at the dam heel. They are all meet the requirements of strength. The concrete of the dam with design water level meet compressive strength requirements, does not meet tensile strength requirements. The maximum tensile stress is1.97MPa, which appear at the bottom an d top of the spillway tunnel, the bottom of the guide wall. It exceeds the tensile strength. Due to the dam tilting to the downstream, the maximum value of compressive stresses is5.0MPa, appearing around the corner of the dam face, on both sides of the guide wall and the dam toe.3、The main stress of the dam is press stress.Perpendicular to the spillway tunnel, the press stress of the dam gradually increased, from both sides of the wall section extending to the lower left and lower right corner. Due to the grouting of drainage gallery, stress concentration appear at the formation of irregular triangle, the lower right side; tensile stress exist only on the underside just below the roof.The location of the spillway tunnel in Monolith center right, the maximum stress appears in the bottom right of the spillway tunnel, which is about1.02MPa. P art of the stress appear at the right of the spillway tunnel, the top of an extension to the upper right corner to the edge position, to the left until the conveyance and bottom of the cave.4、No matter the gate is open or not, the stress changing regularity of upstream dam and shaft is basically the same, except Leakage of spillway tunnel. Compared to open,the values of stress and strain is smaller when the gate is closed.At the intersection of the top of the spillway tunnel and shaft stress is formed a peak at Y=5m.It was0.57MPa.It is because that both sides of the shaft exist elevation difference, suffering load pressure, forming a peak stress.5、The nonlinear finite element model of spillway section is built by ANSYS software. The dam with empty reservoir is in the elastic range, which is no plastic strain. Design conditions dam existence of the plastic deformation region, mainly in the cave surface of the gate support beam and flood and intersect the water exit of the guide wall, The maximum distance is1.59×10-4m at the support beam.6、Elastic simulation stress value is more then the elastic-plastic simulation stress value. The similar project using elastic simulation can meet engineering requirements. |
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