钻孔灌注桩后压浆作用机理与应用

通过对桩侧和桩底后压浆,可大幅度提高钻孔灌注桩单桩承载力.应用桩-土理论分析了后压浆中浆液对土体及桩体的作用,并从分析影响桩基承载力的因素出发,研究了后压浆的作用机理.在渗透率小的地层中后压浆以压密注浆为主,在渗透率大的地层中后压浆以渗透注浆为主.为避免过分压裂土层,在压浆过程中应控制灌浆压力.压浆量是影响后压浆质量和提高单桩承载力的关键因素之一.

Mechanism and Application of Post Pressure Grouting of Bored Pile

The bearing capacity characteristic value of a single pile can be increased greatly through post pressure grouting from pile sides and bottom. The paper analyses mechanism of the post pressure grouting bored pile based on studying the action of grouting fluid on pile and soil on the basis of the interaction theory of pile and soil, and through investigating the factors affecting beaming capacity of the pile foundation. In terms of working mechanism in poor permeable stratum, compaction appears to be main action while in permeable stratum,seepage seems predominant. It is suggested that the pressure should be controlled in a certain limits to avoid unduly fracture to the soil. The amounts of cement slurry is the key factor affecting bearing capacity of the piles.