Abstract：Extended foundation of Baihetan high arch dam is considered as an important form of reinforcement to adapt to the unfavorable geological condition of the left bank foundation，the evaluation method research of its reinforcement effect is not yet fully definite. Three-dimensional numerical model was built，coupling with elaborate simulation of the foundation structure，and the reinforcement effect analysis of extended foundations conducted through elasto-plastic finite element method，during which an evaluation method was proposed based on deformation reinforcement theory. The result shows that extended foundation can help to increase the integral rigidity of dam body，improve the symmetry of the left and right arch abutments deformation and the stress state of rock mass near the base surface. The unbalanced force and plastic complementary energy(PCE) were taken to quantize the reinforcement effect. During the overloading process，the unbalanced forces of dam faces，dam toe and dam heel，area of dam surface yield zone were reduced by extended foundation，while the PCEs of different statistical parts consequently decrease as well. Thus，the stabilities of these critical region of arch dam engineering were promoted by it. The research focusing on the extended foundation proves the necessity of this reinforcement measure，and will be useful to understanding its reinforcement mechanism，which is also expected to have a vital significance for design and practice of high arch dam engineering.
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2015, Vol. 34 
