黄河冲积互层预制方桩承载特性试验研究与分析

Test and Analysis of Bearing Capacity of Precast Square Piles in the Yellow River Alluvial Interbed

桩周注浆预制抗拔桩在厚冲积层地区的研究与工程应用较少。设计出适合济南厚冲击层地区的桩型与桩周水泥土配合比,并采用足尺试验对不同变量因素下预制桩进行对比研究。试验研究表明:被加大水泥百分比后的水泥土包裹的桩体荷载变形曲线更为平缓,桩体回弹率增大,桩侧阻发挥效果更佳;m值并不是某一地层固有的参数,与试验桩形体动态存在一个急速衰减、缓慢衰减和趋于平稳的过程,最终维持在10~30MN·m^(-4);桩长对抗拔桩的承载特性在一定程度上发挥作用,尚不是主要因素,探讨桩身变形随荷载的发展规律足以证明。现场试桩试验初步研究了厚冲积层地区预制抗拔桩的可行性。

The research and engineering application of the precast grouting pile in the thick alluvium formed zone is less. The mix ratio of the cement soil around the pile and the pile type is designed for the thick alluvium in Ji＇nan,and a full scale test was carried out to study the effect of different variables on the precast piles. The experimental results show that： The increase of the percentage of cement after the pile wrapped in cement soil,the load deformation curve is more smooth,the rebound rate of pile increases,the pile side resistance effect is more obvious; The m is not a fixed parameter of a certain stratum,and there is a rapid attenuation,slow attenuation and a smooth process with the test pile body,and finally maintains between 10 - 30 MN·m-4; It is still not a key factor to study the bearing characteristics of pile length against the uplift pile,and the deformation of pile body is proved with the development rule of load. The feasibility of the prefabricated pile is studied in the field of thick alluvium.