软土地基挤扩支盘桩和直杆灌注桩静载试验与成果分析

本文通过一组在杭州湾北侧滨海软土地基上进行的挤扩支盘灌注桩与普通直杆灌注桩静载荷试桩的成果资料对比分析,探讨了新型挤扩支盘桩在上海滨海软土地基上的适宜性。试验结果表明:利用在一定厚度的粉性土和砂性土层中设置支和盘所形成的挤扩支盘桩,可以获得比普通直杆灌注桩更高的单桩承载力。荷载试验变形曲线表明,支盘桩在软土中的破坏形态表现为缓变型。文章同时按不同地区现行技术规程所建议的单桩承载力估算公式进行了承载力计算和分析比较。

Analysis of results and static loading test of squeezed branch pile and boring pile with constant section in soft soil ground

Through comparison and analysis of results data of static loading test for a group of squeezed branch piles and boring piles with constant section performed in soft soil ground close to north Hangzhou Bay, the applicability for new squeezed branch pile used in Shanghai coastal soft soil foundation has been discussed in this paper. The results of loading test indicate that the formed squeezed branch pile set branched and plated in silt and sandy soil with some thickness will get higher capacity of single pile compared with common boring pile with constant section. The deformation curve of loading test also indicates that the failure type of squeezed branch pile takes on a shape of sloped curve in soft soil ground. The calculation of capacity of single pile as per estimated formula recommended by currently issued technical specification in different region and analysis comparison have also been conducted in this paper.