桩侧注浆提升既有桩基承载特性试验与数值模拟

Experimental and Numerical Simulation of Existed Pile Foundation Bearing Capacity by Pile-side Grouting

为揭示粉质黏土地层既有桥梁桩基的桩侧注浆加固机理,通过模型试验研究了注浆压力、水灰比对桩侧土体加固模式及加固效果的作用关系,采用数值模拟获取了桩侧注浆对既有桩基承载特性作用规律。研究结果表明,水泥单液浆在粉质黏土地层中以挤密劈裂的加固方式为主,水泥浆液扩散模式呈现直线式、放射式;粉质黏土注浆加固效果与注浆压力正相关,随水灰比的升高而呈现先升高后降低的趋势。桩基桩侧加固可以有效地提高加固范围内的侧摩阻力,桩基深部相较浅部侧摩阻力提升更明显。

In order to reveal the mechanism of pile-side grouting reinforcement of existing bridge pile foundations in silty clay stratum,the relationship between grouting pressure and water-cement ratio on the reinforcement effect of pile-side soil was investigated through model tests,and numerical simulations were used to obtain the law of pile-side grouting on the bearing characteristics of existing pile foundations.The research results show that the cement slurry is squeezed and split reinforced in the silty clay,and the diffusion pattern shows linear and radial.The grouting silty clay reinforcement effect is positively related to the grouting pressure,and it shows the trend of increasing and then decreasing with the increase of water-cement ratio.Pile side grouting reinforcement can effectively improve the lateral friction resistance within the reinforcement area,and the deep part of the pile foundation has more obvious improvement of lateral friction resistance compared with the shallow part.