中文摘要：

通过三维非线性有限元计算和地质力学模型试验方法,分析无缝和有缝处理2种工况下,裂缝对小湾拱坝坝体应力分布、整体稳定性的影响以及裂缝进一步扩展的可能性。计算结果表明,2种工况的坝体应力分布基本相同,裂缝对坝体应力的分布影响不大。正常荷载下,裂缝基本全部处于压剪状态,不存在或存在很小的拉应力;裂缝继续开裂扩展的可能性不大。在超载工况下,有缝处理工况下非线性荷载为（3.2～3.3）P0（P0为正常水荷载）,与无缝工况下的3.5P0接近;超载3.0P0之后,大坝裂缝局部地方出现开裂区,但整体上直到5.0P0后裂缝才影响到开裂区。大坝极限开裂状态与无缝情况下类似,有缝处理和无缝情况的整体稳定性相差不大。

英文摘要：

With the three-dimensional nonlinear finite element analysis and geomechanical model of rupture test,focusing on analysis of the results of no crack working condition and crack after treatment working condition,the influences on Xiaowan arch dam stress distribution and global stability are studied as well as the possibility of crack propagation.The result indicates that the dam stress distributions of two working conditions are almost the same and the influences of crack are negligible.Under the normal water load,nearly all cracks are in the pressure-shear condition;and the tensile stress is small or does not exist,so the crack will not expand.After the dam overload test,the nonlinear load between 3.2P 0 and 3.3P 0（P 0 is normal water load） after the crack is dealt with,which is quite close to 3.5P 0 in the no crack working condition;limited parts of the dam cracks become large-crack area after overloading 3.0P 0,but the influences of crack will not reach the crack area until overloading 5.0P 0 .The dam cracking limit state is similar to that of no crack working condition,but large difference of global stability between the two working conditions is found.