深厚粉质地层钻孔灌注桩桩端后压浆技术

Pile end post-grouting technology of bored pile end in deep silty strata

在深厚粉质地层中,超长钻孔灌注桩施工存在一定的塌孔风险,成孔和成桩质量较难保证。桩端后压浆可以有效加固桩端沉渣和一定高度范围内的桩侧泥皮,提高桩端阻力和桩侧摩阻力。在保证承载力不变的前提下,直径1.2 m和1.5 m两种基桩的长度可由62 m缩短至55 m,从而降低施工过程中的风险。声测管可兼作桩端压浆钢管,通过在钢管底部安装特制压浆头,实现加固浆液顺利注入持力层。

In the deep silty strata,the super-long bored castin-place pile has the risk of hole-collapsing,and it is difficult to guarantee the quality of the hole-boring and the concrete-casting.The pile end post-grouting technology can effectively reinforce the bottom sediment and the side mud cake in a certain height.It can increase the pile end resistance and the pile side friction resistance.By using the pile end post-grouting technology,the pile length can be shortened from 62 m to 55 m for the diameter of 1.2 m and 1.5 m pile,keeping the bearing capacity remains constant.The construction risk can be reduce.The postgrouting pipe and the sonic logging pipe can be combined.By installing a special grouting nozzle at the bottom of the sonic logging pipe,the reinforcement grout can be smoothly injected into the bearing layer.