海工环境下预应力高强混凝土管桩使用寿命计算

针对海工环境中的预应力高强度混凝土(PHC)管桩,考虑离心分层,将其使用寿命分为诱导期和发展期.对诱导期氯离子输运进行计算,采用差分法对Fick第二定律进行解答,求解诱导期寿命,而发展期寿命采用弹性力学理论求解.计算表明,诱导期和发展期寿命与保护层厚度分别呈线性和指数变化关系,砂浆层厚度增大时,发展期寿命急剧减小,内部封闭可增大PHC管桩使用寿命3~4倍.通过对PHC管桩180d氯盐侵蚀实验,验证了诱导期计算理论的准确性.

Service Life Prediction of Prestress High Concrete Pipe Piles in Marine Environment

Abstract： Chloride induced reinforcement corrosion is the main factor in marine environment for concrete member. The service life of PHC prestress high concrete (PHC) pipe pile was divided into the initiation period and propagation periods. The initiation period, i.e., the chloride transportation time was calculated by Fick’s 2nd law using the difference method. And an elastic mechanics theory was used to solve the propagation period. The results show that the initiation period and the propagation period present linear and exponent relationship with the cover thickness, respectively. The propagation period is greatly decreased as the mortar layer thickness increases. In addition, the service life can be increased to 3 to 4 times by sealing the inner space. Finally, the calculation accuracy of the initiation period was verified by a 180 days chloride erosion test.