上海地区基坑底部粉质黏土回弹变形参数分析

根据压缩试验的回弹—再压缩曲线,得到了根据回弹指数及孔隙比计算回弹模量的理论公式.通过对大量上海地区相关土层勘察资料的统计分析,得到了上海地区⑤层、⑥层、⑧层粉质黏土回弹指数、压缩指数与塑性指数和比贯入阻力之间的线性关系.由于塑性指数和比贯入阻力不受取样扰动影响,可利用这些统计公式估算回弹指数,并结合上述理论公式进一步求得回弹模量.经多个实例验证,此方法精度可满足工程实践需要,且方便可行.研究结果可用于缺少回弹变形试验参数工程的回弹变形量验算.

Statistical Analysis for Rebound Deformation Parameters of Silty Clay at Bottom of Deep Excavation in Shanghai

The theoretical formulation using rebound index and void ratio of rebound modulus has been deduced through the curve of compression test. The linear correlations of rebound index, compression index, plasticity index and specific penetration resistance for the silty clay on the fifth, sixth and seventh layer in Shanghai was observed according to a large number of survey data in Shanghai.The rebound index was obtained by means of the previous empirical formula firstly. Then the rebound modulus can be gotten through the theoretical formula. This method is verified to meet the needs of engineering practice. The results can be used for checking the rebound deformation in the conditions of lacking rebound deformation parameters.