静水条件下超疏水性对混凝土 I 型裂缝扩展的影响

高水压力随水流浸入作用于结构缺陷或裂缝缝面导致结构开裂或裂缝扩展的工程问题在国内外多座高坝中均有发生。超疏水混凝土表面对水分具有较强的排斥作用，水流浸入裂缝的范围小于普通混凝土，对于上述工程问题应具有抑制作用。为此，将裂缝受力扩展考虑为 Boussinesq 问题，并借鉴 Westergaard 应力函数，推导了集中荷载下的缝面位移函数和均布荷载下的缝面位移和裂缝延长线应力函数。根据应变能释放率理论，建立了水流入浸导致裂缝扩展的计算模型与迭代步骤，可以进行不同疏水性材料裂缝扩展的定量分析。算例分析表明，相对普通混凝土，超疏水混凝土对高水压下的裂缝扩展具有较好的抑制作用，而且超疏水混凝土裂缝尖端具有更好的应力状态。

Effect of super-hydrophobicity on type I crack propagation of concrete under hydrostatic condi- tion

The engineering problems of structure cracking and crack propagation induced by the high water pressure acting on the structural defects or the surfaces of existing cracks occur frequently in many high dam projects at home and abroad． Due to the strong repulsive effect of the surface of super-hydrophobic concrete on water，the extent of water intruding into its crack is smaller for the super-hydrophobic concrete than that for common concrete，thus the aforementioned engineering problems can be restricted． For this reason，the crack propagation under stress is considered as a Boussinesq problem and Westergaard stress function is used for reference，and then the function of crack surface displacement under concentrated load and the functions of crack surface displacement and the stress on crack extension line under uniformly distributed hydrostatic pressure are deduced． In accordance with the theory of strain energy release rate，the calculation model for crack propagation induced by water intrusion and the relevant iterative steps are proposed herein，by which the quantitative analyses on the crack propagations of the materials with different hydrophobicities can be carried out． The analysis made on the relevant calculation example shows that compared with the common concrete，super-hydrophobic concrete has stronger restricting effect on crack propagation under high water pressure with a better crack tip stress state．