砂砾地层后注浆灌注桩承载性能试验研究

后压浆技术从一定程度上有效地消除了传统钻孔灌注桩在施工中的固有缺陷,改善了桩周土层的物理力学性质以及桩与土之间的边界条件,有效地降低了桩的沉降量,显著提高了单桩承载力。对砂土地层的100根注浆试桩的单桩注浆量进行数据统计,分析了桩端注浆量的变化规律;结合沈阳夏宫工程五根桩端注浆桩和两根未注浆桩的静载试验,对比分析了注浆桩与未注浆桩的单桩极限承载力以及桩顶沉降量。研究结果表明:在砂土地层条件下,注浆桩单桩竖向极限承载力比非注浆单桩竖向极限承载力能提高44.4%以上,而且在相同荷载作用下,后注浆抗压桩桩顶位移比未注浆桩的降低了近50%,有利于控制基础的沉降。

Research on the load bearing characteristics of post-grouting for bored piles in the sandy gravel stratum

The traditional bored pile inherent defects in the construction are eliminated by the post grouting technology in a certain degree and effectively, the physical and mechanical properties around piles are improved, the boundary between the pile and soil conditions is also improved, the settlement of pile is reduced effectively and the bearing capacity of single pile is increased significantly. With the statistic on grouting quantities of ｜00 root piles, varying pattern of grouting quantity is studied, and is combined with the site test results, the bearing performances of seven piles of Shenyang Summer Place project have been tested, the five of them are post grouted under the pile tip and the other two are no-post grouted. According to the results of the static loading tests, the vertical ultimate bearing capacity of single grouting pile can increase more than 44.4% than no-grouted. The settlement of grouting pile top is reduced 50% than no-grouted under the same load. The rigidity of the pile is raised which makes the settlement of pile be easier to control.