后压浆灌注桩在黄河冲积平原区砂层中的承载特性研究  

Study on Bearing Characteristics of Post-Grouting Bored Pile in Sand Layer of the Yellow River Alluvial Plain Area

作　　者：张学臣 ZHANG Xuechen(China Railway Construction Group Co.Ltd.,Beijing 100040,China)

机构地区：[1]中铁建设集团有限公司,北京100040

出　　处：《铁道建筑技术》2024年第10期126-130,共5页Railway Construction Technology

基　　金：国家自然科学基金项目(50978086、51178165);中铁建设集团有限公司科技研发计划项目(20-37c)。

摘　　要：为揭示砂层土中后压浆灌注桩竖向承载机理,以郑州黄河冲积平原区的两个后压浆灌注桩项目为依托,开展不同注浆量下后压浆灌注桩现场试验,研究单桩竖向承载力、桩周侧摩擦阻力和桩端阻力随注浆量变化演化规律。结果表明,单桩竖向承载力随注浆量增加逐渐增大,但增幅逐渐减小;桩端和桩侧同时注浆时可在桩端附近形成共同影响区域,有效提高桩端与加固土体的接触面积,进而促进桩端阻力和桩侧摩擦阻力有效发挥;砂层中实测桩端增强系数至少为规范值的1.8倍,在设计及施工时应合理控制后压浆的注浆量,以提高桩基工程的经济性和适用性。To elucidate the vertical bearing mechanism of post-grouting bored piles in sandy soil,field tests were conducted on two post-grouting bored pile projects in the Yellow River alluvial plain area of Zhengzhou.The on-site tests were conducted on post-grouting bored pile with different grouting volumes to investigate the evolution law of the single pile vertical bearing capacity,pile side friction resistance,and pile tip resistance with varying grouting volumes.Results indicate that the single pile vertical bearing capacity gradually increases with increasing grouting volume,albeit with diminishing increments.When grouting is conducted simultaneously at the pile tip and pile side,a shared influence zone forms near the pile tip,effectively increasing the contact area between the pile tip and the reinforced soil mass,thereby enhancing the effective utilization of both pile tip and pile side frictional resistances.The measured pile tip enhancement factor in the sandy layer is at least 1.8 times the specified value,suggesting the need for judicious control of grouting volume during design and construction to improve the economic feasibility and applicability of pile foundation engineering.

关 键 词：后压浆 桩侧摩阻力 桩端阻力 增强系数 单桩竖向承载力 现场试验 

分 类 号：TU473.1+4[建筑科学—结构工程]