中川铁路饱和黄土地基水泥土搅拌桩静载试验研究

摘要

Based on the railway engineering project from W estern Lanzhou to Zhongchuan airport,static load test on cement-soil mixing piles( on saturated loess foundation) as well as on integrated single-pile foundation were carried out. T he results indicate that in comparison with the foundation of natural saturated loess,the integrated foundation supported by cement-soil mixing piles with a 12% ~20% additive ratio of cement and fly ash shows a 48% ~88%increase in bearing capacity. And the growth of additive ratio brings up the bearing capacity of both the pile and the foundation at large. As the loading imposed to the upper structure goes up,the stresses at pile top and soil between piles grow by different amplitude,while the stress ratio of pile soil increases at first and falls at the later stage. It can be calculated that in this case the bearing efficiency β of soil between piles stands at 1. 09.%依托兰州西至中川机场铁路工程，对饱和黄土地基条件下水泥土搅拌桩进行单桩及单桩复合地基静载荷试验。结果表明：相比天然饱和黄土地基，二灰掺合比为12%～20%的水泥土搅拌桩复合地基承载力特征值提高约48%～88%；随着二灰掺合比增大，水泥土搅拌桩单桩承载力及复合地基承载力均增大；随着上部荷载的增加，桩顶与桩间土应力会不同幅度增大，桩土应力比先增大后逐渐减小。通过计算得出，中川铁路饱和黄土地基水泥土搅拌桩复合地基桩间土承载力发挥系数为1.09。