重力坝横缝止水至坝面距离对防止坝面劈头裂缝的影响

Effect of the distance between transverse joint seal and dam surface on the cleavage cracks in dam surface

在混凝土重力坝、尤其是通仓浇筑的重力坝上游面， 往往出现严重劈头裂缝。为了防止这种裂缝的出现，必需加强温度控制， 并加大横缝内止水至坝面的距离， 利用缝内水压力， 在坝体上游面产生压应力， 以减小劈头裂缝出现的可能性， 但这种影响目前尚无法定量分析。经研究给出一个计算方法， 计算结果表明， 止水至坝面距离以达到横缝间距的０２５～０４５ 倍为宜。这一计算方法和结论对于常规混凝土重力坝和碾压混凝土重力坝都是适用的。

Serious cleavage cracks often occur in the upstream surface of concrete gravity dam, especially thorough pouring concrete gravity dam In order to prevent such cracks, the temperature control should be strengthened and the distance between the water seal in the transverse joint and the dam surface should be increased Using water pressure in the crack produces compressive stress in the upstream surface of dam to reduce the occurrence probability of cleavage crack But such influence cannot be quantitatively analyzed at present This paper gives a calculation method The calculation results show that it is suitable for the distance between the water seal and dam surface reaching a value of 0 25 0 45 times of transverse joint space