Stress concentration and high stress gradient around foundation interface (dam-rock foundation contact surface) are key factors cause different failure modes occur. Proper treatments are sometimes necessary in the downstream toe of arch dam to ensure the three-dimensional compression states to increase the anti-shear strength and bearing capacity of rock mass. Based on the deformation reinforcement theory and integral overloading analysis for high arch dam by employing 3D nonlinear finite element method, this paper elucidated basic ideas of reinforcement force, definition of reinforcement force, and solution of reinforcement force of downstream toe of high arch dam. By applying reinforcement force analysis on the treatment of downstream toe of Ertan arch dam and Xiluodu arch dam, the design standard of reinforcement for foundation is preliminarily discussed in detail, and the results show proposed reinforcement force analysis method is effective for quantitative solving reinforcement force for foundation of high arch dam under different loading conditions.
Stress concentration and high stress gradient around foundation interface (dam-rock foundation contact surface) are key factors cause different failure modes occur, such as tensileshear cracking in heel of dam and compressionshear cracking in toe of dam[1–3]. When the cracks coalesce between dam heel and dam toe, foundation will cause instability sliding, eventually lead overall dam to failure. Thus, proper treatments are sometimes necessary in the dam-toe areas to ensure the three-dimensional compression states to increase the anti-shear strength and carrying capacity of rock mass. If treatment, such as grouting, backfill concrete or anchor is used to simple and effective measure of applying reinforcement force for foundation, its effects on the physical properties of the foundation and stress distribution of dam should be considered during the analyses. 3D nonlinear finite element method is widely used to analyze stress condition and entire stability of arch dam in research [4–6]. The entire instability criteria of arch dam consist of the convergence of calculation and join of yield zone, as well as some energy instability criteria [7–8]. Although they can be referred to analyze the entire stability of arch dam, it is immature to apply them to actual reinforcement design. Up to now, unified approaches and criteria are deficient to reinforcing design and effective evaluation. If reinforcement measures are only considered for calculation, and then carry out finite element analysis, the results show that they have little effects on deformation, stress distribution, and yield zone scale of structure in design condition, which does not tally well with actual situation [9–13]. Thus, in this paper, based on the deformation reinforcement theory and integral overloading analysis for high arch dam by employing 3D nonlinear finite element method, the authors have proposed another criterion for design and evaluation that whether reinforcement measures will help to improve the stability of arch dam 954 under overloading condition.
