GRF基础承载机制试验研究

GRF基础是一种新型桩基础，首先开发应用于日本，与普通直桩相比，该基础不仅可以节约材料、降低成本，而且可以大幅度地提高承载力，具有广阔的应用前景。通过模型试验，分析了锚杆间距、锚杆长度以及锚杆数量对GRF基础承载力的影响，初步探讨了GRF基础的承载机制。得到以下结论：GRF基础的承载性状和直桩不同；锚杆不仅可以提高GRF基础的侧阻力，在一定程度上对端阻力也有增强作用；在相同的桩顶荷载作用下，GRF基础的位移远小于直桩的位移；与同体积的大直径桩相比，GRF基础可以大幅度地提高基础承载力、减少沉降；在一定的锚杆间距范围内，锚杆间距对极限承载力的影响较小，但对极限侧阻力影响较大；存在一个锚杆临界长度，当锚杆长度为临界值时，锚杆利用效果最佳；GRF基础的极限承载力随锚杆数量而变化，适当地增加锚杆数量，可以获得满意的承载力增量。

Experimental research on bearing mechanism of geo-reforcement foundations

Geo-reforcement foundation is a new type of pile foundation that is firstly developed and utilized in Japan. Compared with normal straight pile, this type of foundation can not only save materials and cut cost, but also can increase the bearing capacity greatly; so its application prospect is wide. Through model tests, the influences of anchor space, anchor length and anchor number on the bearing capacity of geo-reforcement foundation are analyzed; and some preliminary studies of the bearing mechanism of geo-reforcement foundation are made. The conclusions are as follows: the bearing behavior of geo-reforcement foundation is different from that of straight pile; the anchor can not only increase the side resistance of geo-reforcement foundation, but also increase the tip resistance to some extent. When the load on the pile top is the same, the displacement of geo-reforcement foundation is much less than that of normal straight pile; compared with large diameter pile with the same volumn, geo-reforcement foundation can greatly improve the foundation bearing capacity, reduce the settlement; when the anchor space is in some range, it effects the ultimate bearing capacity smally, while functions greatly on the ultimate side resistance; existing a critical anchor length, when anchor length is the critical length, its utilization effect is best; the ultimate bearing capacity of geo-reforcement foundation varies when the anchor number is different; and we can gain a satisfying bearing capacity increment by increase the anchor number appropriately.