Abstract: With the action of trafic load and temperature，defects and cracks emcee on the bottom of tile concrete pavement slabs．Accompanied with the failure of the stuffing，water may be accumulated under the slabs，and because of tile high speed traffic load，the water pressure will reach to a large extent．To the cracks on tile bottom of the slabs，the efect of water is just like the uniform forces assigned on the crack face which lead to the cracks to split．With fracture mechanics，the prin- ciples of the split effect of water was disclosed；meanwhile ，from the view point of stress，the split efect of water pressure through plane finite element method was evaluated．The conclusion is useful and helpful to analyze the fracture of concrete slab．

Key words: cement concrete pavement, concrete slab, water pressure, crack on the bottom of slab, split

摘要： 水泥砼路面在荷载、温度等的作用下，扳底会出现缺陷、裂纹，随着填缝料的失效，水在板底积聚，在行车茼载 的作用下．板底水压力会达到一个相当大的程度．对于板底裂纹丽言，水的作用相当于在裂纹面上施加了促使裂纹 扩展的均布劈裂力，运用断裂力学原理揭示了水对裂纹的劈裂作用，同时采用平面有限元从应力角度考察r水压对 裂纹的劈裂影响．x寸于水泥砼路面板的断裂分析具有一定的理论意义．

关键词: 水泥砼路面, 砼面板, 水压力, 板底裂纹, 劈裂