锚杆静压钢管桩桥梁基础加固方案试验研究

Experimental study on reinforcement scheme of bridge foundation with anchor bolt static steel pipe pile

某32.5m跨预应力T梁简支梁桥基础承载能力不足,威胁桥梁运营安全。经分析,该桥基础承载能力不足的原因为早期桥梁建设对灌注桩基础施工质量控制的认识不足,从而产生桩长桩径不足、桩身混凝土空洞、桩头砼质量差且与承台联系较弱等病害。因受桥下净空限制、主要地层为淤泥质土,故采取锚杆静压钢管桩进行基础加固,使桥墩承载力符合规范要求。采用应变监测及荷载试验验证,结果表明钢管桩承载力趋于稳定,分担原基础荷载效果良好,有效提高了桥梁承载能力。

The bearing capacity of the 32.5 m span prestressed T-beam bridge foundations are insufficient,which threatens the safety of bridge operation.Through analysis,the insufficient bearing capacity of the foundations are caused by the early bridge construction insufficiently awareness of the quality control of cast-in-place pile,resulting in such diseases as insufficient pile length and diameter,pile body concrete cavity,poor concrete quality of pile head and weak connection with pile cap.Due to restricted by the clearance under the bridge and the main stratum is silt soil,the anchor bolt static steel pipe pile is adopted for foundation reinforcement,so that the bearing capacity of the bridge pier meets the requirements of code.The results of response monitoring and load test show that the new steel pipe piles supporting force tends to be stable,and the effect of sharing the load of the original foundation is good,which effectively improve the bridge loading capacity.