公路桥梁后压浆灌注桩承载力计算模式试验研究

Test and Study on Calculation Method of Bearing Capacity for Cast-in-place Bored Pile with Post Grouting Technique in Highway Bridges

为进一步剖析后压浆工艺对公路桥梁钻孔灌注桩侧阻力、端阻力及极限承载力的作用机理,从而为确定合理的承载力计算模式奠定基础,在总结既有计算公式的优势和不足的基础上比选获得了具有适应性的计算方法,以西安咸阳国际机场专用高速公路渭河特大桥桥址作为试验比选区,制作了2组试桩及1组工艺桩进行了静载试验及注浆性状直观剖示试验研究。结果表明,由于沉渣固结及泥皮置换作用使得后压浆桩基承载性状得到了充分发挥,应用建科院公式更能够反映后压浆桩的承载力状况,研究成果可直接应用于同类型桩基的设计中。

In order to make further analysis on the mechanical performance of resistance force at the side or end of cast-in-place bored pile with post grouting technique for highway bridges, the reliable calculation method of bearing capacity is studied. In this paper, merits and demerits for common formula of load carrying capacity are summarized to determine applicable one. On the basis of two groups of trial pile and one group of craft pile in the same geological region of Weihe Bridge, which located at new airport construction project of Shaanxi Province, it shows that the pile-soil interaction are fully realized because of sediment consolidation and mud skin replacement. The formula of CABR is more suitable for calculation on bearing capacity of post grouting pile. In conclusion, the research results can be applied to the design of bridge foundation.