注浆作用对微型钢管桩抗压承载性能影响的试验研究

为了研究注浆作用对钢管桩承载性能的影响,本文开展了160 mm、200 mm两种桩径、5 m和8 m两种入土深度、注浆与不注浆两种条件下共18个试验桩的现场抗压静载荷试验,分析了注浆作用对钢管桩荷载位移曲线、极限承载力及破坏模式的影响。结果表明:注浆作用使钢管桩荷载位移曲线上的中间曲线段更加明显,塑性变形范围增加;注浆作用整体提高桩基承载力30%以上,管径最细、埋深最浅的I#桩提升效果最明显;注浆过程中浆液在桩周土中产生劈裂、渗扩、填充、胶结、压密等一系列物理化学作用,最终在桩端形成“水泥土加固体”,在桩侧形成水泥土护壁,改善了桩端土、桩周土的物理力学性能,从而提高了桩基承载力。

Experimental Study on the Influence of Grouting on the Compressive Bearing of Micro Steel Pipe Pile

In order to study the influence of grouting on the bearing capacity of steel pipe pile, this paper has carried out the field compressive static load test of 18 test piles under the conditions of 160 mm and  200 mm pile diameter, 5 m and 8 m soil depth, grouting and non-grouting, and the influence of grouting on the load-displacement curve, ultimate bearing capacity and failure mode of the steel pipe pile was analyzed. The results show that the grouting effect makes the middle curve of the load-displacement curve of the steel pipe pile more obvious, and the plastic deformation zone increases. The bearing capacity of the steel pipe pile increases more than 30% due to grouting, especially for I # pile with the minimum diameter and depth. In the process of grouting, a series of physical and chemical actions such as splitting, seepage expansion, filling, cementation and compaction occur in the soil around the pile. Cement soil and solids are formed at the end of the pile, and cement soil retaining wall is formed at the pile shaft, which improves the physical and mechanical properties of the soil at the pile tip and around the pile, thus improving the bearing capacity of the steel pipe pile.