中文摘要：

混凝土坝的坝踵部位属高应力梯度区，是混凝土坝应力分析的关键部位。本文通过精细网格模拟研究了重力坝坝踵应力情况，就均质坝基和非均质坝基弹模变化对坝踵主拉应力的影响，得出了如下结论：①均质坝基弹模与非均质坝基敏感区域的变异单元弹模变化相同的幅度，非均质情况引起的坝踵应力的变化远大于均质情况。在用精细网格对坝踵进行模拟时，应同时考虑到该网格水平材料的非均质性，否则，精细网格计算也可能是徒劳的。②在非均质坝基情况下，坝踵最大主拉应力对坝踵相邻岩体（〈1米）弹模变化极为敏感，稍远处局部岩体弹模的变化则影响很小。

英文摘要：

Dam heel is the area of high-gradient stress, and it is critical in the stress analysis of the concrete dams. This paper studies the stress of gravity dam heel with careful numerical simulation, and analyses the effect of the variety of the elastic modulus of homogeneous or non-homogeneous foundations on the principal tensile stresses of gravity dam heel. The conclusions are as follows：① When the elastic modulus of homogeneous dam base and variated element in the critical place is changed with the same the fluctuation, the effect on the dam heel stresses caused by the latter is much more prominent than the former one. So, when simulating the dam hell, the nonuniformity of the dam base must be taken into count. Otherwise, the result can＇ t be right.②Under the base of uniformity the maximum principal tensile stress of gravity dam heel is very sensitive to the variety of the elastic modulus of the nearby rock（ 〈 1m）, and the rock in a little far away position from the dam heel is of little influence on the principal stresses of gravity dam heel.