原位十字板试验评价上海软黏土灵敏性的可靠性

详细分析了上海某工程勘察数据以及相关文献资料,发现FVT试验得到的灵敏度要明显小于UCT试验结果,因而会不同程度地低估上海地区各软黏土层的灵敏度。进一步研究表明,十字板重塑方式(而不是手工重塑)是造成FVT试验得到重塑土强度过高因而灵敏度偏低的主要原因,而这两种试验采用的试验方法以及原位应力对灵敏度测试结果的影响并不大。这种现象应引起工程界的重视以便正确评价我国沿海地区广泛分布的海相沉积软黏土的结构性和灵敏性。

Reliability of FVT for sensitivity evaluation of Shanghai soft clay

The geotechnical investigation data from a real project in Shanghai as well as other relevant published data are analyzed. It is found that the sensitivity obtained by the FVT test is significantly smaller than the results of the unconfined compression test (UCT). Thus the sensitivity of soft clay will be underestimated by FVT. The vane-shear remolding method (not the artifical remolding method) makes the FVT obtain much higher remolded strength and therefore the lower sensitivity than UCT. The influences of test methods and in-situ stress state can be neglected. It is pointed out that much attention should be paid to this phenomenon in order to properly evaluate the sensitivity of the marine soft clay distributed in the coastal areas of China.