水泥粉煤灰搅拌桩复合地基桩土应力比试验研究

通过水泥粉煤灰搅拌桩复合地基试验段内桩土应力的现场监测结果，探讨了柔性荷载作用下桩土应力比的变化趋势及影响因素，并根据监测结果对地基处理方案进行评价和优化。试验结果表明:在路基填筑期期内，随着上部荷载的桩体、桩间土应力不断增大，桩土应力比的总趋势为增大。路基固结稳定期内，桩土应力比值变化不大。在填土高度5 m以内的柔性路基作用下，水泥粉煤灰搅拌桩复合地基中桩土应力比的变化范围为2.18～2.71，远小于单桩承载力测定的3.0～10.0。

Experimental Study on Pile-soil Stress Ratio of Composite Foundation for Fly-ash-cement Mixing Piles

Depending on field monitoring results of pile-soil stress in test section of composite foundation for fly-ash-cement mixing piles, the variation tendency and the factors affecting pile-soil stress ratio under flexible load are discussed and then the foundation treatment schemes are evaluated and optimized. The result shows that during subgrade filling, generally, pile-soil stress ratio trends increasing as the pile stress and pile-soil stress under upper load increases; during subgrade consolidating and stabilizing, this ratio changes small; and under the action of flexible subgrade with the filling height not more than 5m, this ratio varies from 2. 18 to 2. 71, far less than the value of 3.0 - 10. 0 measured with bearing capacity of single pile.