Spatial Elasto-plastic Finite Element Anslysis Of Shigao Mountain Arch Dam

The stress analysis problem is very important in the design and study of arch dam. With the development of computer technology, finite element method (FEM) is widely used. Finite element method in calculation of arch dam stress cannot only consider the overall effect of arch dam and its foundationbut also the body orifice, gallery openings, and the dam could be considered under all kinds of complicated conditions of stress distribution and stress analysis. The Arch of offloading the perpetrators could not do this. Temperature is an important load of arch dam design. Analysis of observed data show that, when the cause of total radial deflection is changes in water pressure and temperature, the latter accounted for1/3-1/2, and the closer to the crest section, the temperature changes more visible. Therefore the study of effects of temperature change on arch dam becomes extremely important.In this paper, Application of ANSYS software on the mountain of Shan xi province project single concrete gravity arch dam has established three dimensional nonlinear finite element model of space, make-abutment of the dam foundation rock mountain-integrated modeling, and the combined effect of dam overflow holes and corridors of analytical methods were considered. The nonlinear finite element analysis of change of stress and displacement with the influence of temperature was discussed and it wasfocuses on stress and displacement in horizontal load and vertical load presented-abutment of the dam foundation rock mountain-integrated modeling combined effects of analysis method was valuable on engineering solutions to similar problems and model calculations on the design and construction of guiding significance.The research content and its main results of three dimensional nonlinear finite element analysis and calculation of ideal elastic-plastic model, are as follows:1、Effect of temperature variation on the structural deformation:dam under the condition of temperature rise all the way to the uppstream, The closer to the upstream the dam lateral deflection the greater and on the same elevation, upper side deflection is greater than the downstream side. Under the condition of the temperature drop the dam all the way to the displacement of the lower, and the closer to the arch top beam the change to the downstream was greater, and at the same height, basically the same shift in the upper reaches.2、Effect of temperature variation on stress:on normal conditions of temperature rise of water level, tensile stress area focused on both sides of about1/2-1times the height of the Weir, which near the maximum value, of 1288KPa.Maximum tensile stress of gate piers are mainly concentrated in part of the pier on the side near the crest, Pier maximum tensile stress of little value, which is1055KPa distribution on the pier on the right side,; the larger compressive stress was at the two abutments of the dam which is6612KPa.Pier pressure is less than2259KPa. On the condition of normal water level and temperature drop, tensile stress area is mainly concentrated in the part about1/3～1times the height of the dam, the maximum value was near the crown whith is1530KPa. Maximum tensile stress of gate piers are mainly concentrated in part of the pier on the side near the crest, and Pier maximum tensile stress distributed on the pier on the left side was not big and which is of a value of1849KPa. The larger compressive stress was on both sides of the dam abutment, and the maximum value is5164KPa, and Pier pressure is less than3173KPa.3、Effects of orifice and corridor on the stress:Gallery of dam body orifice had significant influence on deformation and stress and which caused the stress distribution. In normal conditions of temperature rise of water level, overflow hole in the lower local the stress concentration phenomenon occurred around, and the maximum area appears in the overflow orifice and left Pier junction, and with the maximum tensile stress value of1994Kpa. At the same time this area was also the plastic stress development area, and with the maximum equivalent plastic strain of0.19mm. ON the condition of temperature drop during normal water level, the stress concentration was also appeared at the lower part around the overflow hole of, and the maximum area appeared at the junction of the overflow weir and sluice pier on the left side and the junction of the left and right piers of both sides and the dam, and the maximum tensile stress value was4660KPa and this area also ws the plastic stress development area, with the maximum equivalent plastic strain of1.46mm. Arch Load method was unable to response the local stress in the hole stress intensity, while the orifice stress distribution could be concentrated by the finite element method.4、Comparison of results:on two conditions in most regions of dam body the tensile stress and compressive stress values are in line with design requirements. Local Weir appeared in the vicinity of excessive partial tension, and under temperature rise at the two corner points of dam abutment there was a great deal of stress.5、Changes in temperature had a greater impact in deformation and internal force of arch, and so we must pay attention to temperature loads on the structure design of arch dam.