灌注桩施工工艺环节多,边界条件复杂,因此,桩尖阻力偏小,浅部发生扩径、缩径和断桩等现象较多。经检测,用扩大桩径(如φ1100mm)的方法提高灌注桩承载力,有待进一步探索;采用凹凸形变径灌注桩或向桩端、桩侧压力注浆等措施,提高钻孔灌注桩的承载力是切实有效的。 The construction process of the cast-in-place piles has many links and the boundary conditions are complex. Therefore, the pile tip resistance is small, and there are many phenomena such as expansion, shrinkage and broken piles in the shallow part. After testing, increasing the bearing capacity of cast-in-place piles by expanding the pile diameter (such as φ1100mm) requires further exploration. The bearing capacity of cast-in-place bored piles is improved by using concave-convex variable-diameter cast-in-place piles or pressure-grouting to pile ends and piles. It is effective and effective.