透水性混凝土桩减压减震耦合抗震机理研究

Anti-earthquake mechanism of pervious concrete pile composite foundation

透水性混凝土桩兼具散体桩和刚性桩的优点,特别适用于地基抗震。为研究其抗震机理,对地震过程中地基的加速度响应和超静孔隙水压力的长消规律等进行了数值模拟,并与碎石桩、素混凝土桩等的动力行为进行了比较分析。研究发现:透水性混凝土桩复合地基表面加速度放大系数明显小于碎石桩和素混凝土桩复合地基,而且其卓越周期仅为碎石桩和素混凝土桩复合地基的1/2,更有利于抑制上部建筑共振的发生;透水性混凝土桩除具有显著的减震效应外,还具有明显的减压效应,其高透水性使地震引起的超静孔隙水压力能快速消散,抑制了地基液化的发生。透水性混凝土桩的减压减震耦合效应还能有效协调地震期间土体的变形。

With the advantages of both granular piles and rigid piles, pervious concrete piles were especially suitable for earthquake-resistance foundation. To study the anti-earthquake mechanism of pervious concrete pile composite founda- tion, the acceleration response and the development and dissipation of excess pore water pressure during the earthquake were numerically simulated. The dynamic behaviors of pervious concrete pile were compared with those of gravel pile and plain concrete pile. The surface acceleration amplification coefficient of pervious concrete pile foundation was obvi- ously smaller than two other pile foundations. Meanwhile, pervious concrete pile predominant period was only half of gravel pile and plain concrete pile foundation, which demonstrated that pervious concrete pile foundation was more ef- fective to avoid the upper building resonance. Besides significant damping effect, the pervious concrete pile foundation also had obvious pressure-reduction effect. The excess pore water pressure induced by an earthquake dissipated quickly because of the high permeability of pervious concrete piles, and the foundation liquefaction was effectively inhibited. Consequently, the draining-damping coupling effect of pervious concrete piles could improve the deformation compati- bility of soil during the earthquake.