碎石注浆桩承载特性试验研究

Bearing behaviors of crushed stone grouting piles

通过室内模型试验及现场试验,对碎石注浆桩这一新型桩基技术的承载性状、工作机理进行了试验研究。试验结果表明,与素混凝土灌注桩和预制混凝土桩相比,碎石注浆桩通过先投放碎石后进行注浆成桩的工艺,在注浆过程中胶结碎石成混凝土提高桩体强度的同时,水泥砂浆也胶结加固了桩侧和桩端土体,使得桩侧摩阻力和桩端阻力均得到显著提高。通过试验分别研究了注浆对桩侧摩阻力和桩端阻力的影响及荷载分担情况,得到了一些有益结论。试验也表明:泥浆护壁的成孔方式对桩体的承载性能有一定削弱作用,通过后注浆的工艺可得到改善。着重对试验方法和结果进行描述分析,得到的一些试验数据和结论可为深入研究碎石注浆桩的加固机理和计算方法提供依据。

The beating behaviors and working mechanics of crushed stone grouting piles, a new technique, are studied by model tests and field tests. The technology of the crushed stone grouting piles is that the crushed stone is firstly placed and then the cement grouting is implanted. Compared with the bored unreinforced concrete piles and precast concrete piles, the test results show that the strengths of the piles, the pile side soil and the pile end soil are improved, which make the frictional resistance and tip resistance increase remarkably. The influence of the grouting on the frictional resistance and tip resistance and the sharing condition of load are studied. Some significant conclusions are drown. Furthermore, the test results also show that mud protection makes the bearing of the piles decrease, and the bearing of pile can be improved by post-grouting. The test method and test data are described. The test data and conclusions offer an important basis for the studies on the reinforcement mechanism and calculation method of crushed stone grouting piles.