武汉某摩擦型灌注桩后注浆单桩竖向承载力试验研究

Experimental Study on Vertical Compressive Bearing Capacity of Single Pile with Post Grouting Technology in Wuhan

摘要:

武汉市某项目典型二元结构地层，稳定砂层平均埋深约50 m，合理桩长范围内无较好持力层，灌注桩沉渣控制困难、成桩工效低。选择深度＞30 m的粉细砂夹粉质粘土层为桩端持力层，通过14根、2组不同桩径及桩长的试桩验证成桩工艺，对比2组试桩的承载特性，提出按规范经验参数取值的不足，以综合性价比和承载稳定性推选直径800 mm、桩长30 m的后注浆摩擦型灌注桩为工程桩参数，为桩基设计优化提供依据及类似工程提供参考。

Abstract:

The paper presents a project with typical dualistic-structural stratum in Wuhan, the average buried depth of the continuous sand layer is about 50m with no proper bearing layer for reasonable pile length, which makes cast-in-place pile sediment control difficult with low pile completion efficiency. More than 30mdepth fine sand with silty clay soil layer is selected as pile end bearing layer, the pile completion technology is verified through 2 separate groups of 14 testing piles with different pile diameters and pile lengths, comparing the load-bearing characteristics of these 2 groups, the shortage of value drawing according to standard empirical parameters is put forward, the post-grouting friction cast-in-place pile, 800mm in diameter and 30m in length, is selected as engineering pile parameter based on the comprehensive cost performance and bearing stability, which can provide the basis for pile foundation design optimization and can be the reference for the similar projects.