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白鹤滩高拱坝地基地质条件复杂,需要设计大范围的垫座以改善受力条件。目前关于拱坝地基和坝肩处理措施的研究大多依赖工程经验,尚没有完整、可靠的垫座评价准则。提出拱坝垫座设计的综合优化方法,通过分析垫座对坝体的影响及垫座自身的稳定性,找到最优的设计方案。该方法综合坝体位移、应力、屈服区、抗滑安全度等因素,采用不平衡力分析坝踵开裂,采用塑性余能范数(PCE)评价垫座整体稳定。不平衡力是结构局部失稳后的度量,能够有效地预测裂纹扩展部位和方向。余能范数是不平衡力的标量范数,可用于判断结构的整体稳定性。对比4种垫座设计方案,通过对坝体位移、坝踵开裂、垫座整体稳定和抗滑安全度的分析,确定将垫座视为坝体、垫座上游侧设缝为白鹤滩拱坝垫座的最优设计方案。
The geological conditions of Baihetan high arch dam foundation are complicated, and a large range of pedestals need to be designed to improve the stress conditions. At present, the research on the treatment measures of arch dam foundation and abutment mostly depends on the engineering experience, and there is no complete and reliable criterion for the evaluation of pedestal. A comprehensive optimization method for the design of the arch dam was proposed. By analyzing the influence of the pad to the dam and the stability of the pad, the optimal design was found out. The method integrates dam displacement, stress, yield zone, anti-sliding safety and other factors, analyzes the heel cracking by unbalanced force, and evaluates the overall stability of the pedestal by using the plastic residual energy model (PCE). Unbalanced force is a measure of local structural instability, which can effectively predict the location and direction of crack propagation. Inequality is the scalar norm of unbalanced forces and can be used to determine the overall stability of the structure. By contrast with the four kinds of pedestal design schemes, the pedestal is determined as the dam by the analysis of the displacement of the dam body, the cracking of the heel, the overall stability of the pedestal and the safety of the anti-sliding. The upstream side of the pedestal is provided with the Baihetan arch dam Pedestal of the best design.