Three series of sampling with thin-walled samplers, with and without inside clearance and without a piston, have been performed in a very soft organic clay deposit. The penetration and retrieval forces were measured throughout the operation, thus contributing to a clearer understanding of the sampling process. The measured forces show the importance of proper borehole cleaning conditions, and also identify when samples were lost during retrieval. This occurs when the underpressure at the sampler bottom does not appear in the retrieval force versus time chart. The obtained values have been compared to the sleeve friction measured by piezocone tests. Direct simple shear (DSS) tests and vane shear tests have been used as references to back-calculate the dimensionless skin friction factor from both sample penetration and retrieval. The measurement of force during sampling proved useful for controlling sampling operation, also providing further information with respect to the regular procedure.

在非常柔软的有机粘土沉积物中，使用带薄壁采样器的三个系列采样（带或不带内部间隙且不带活塞）进行了采样。在整个操作过程中都测量了穿透力和取回力，从而有助于更清晰地了解采样过程。测得的力显示了适当的井眼清洁条件的重要性，并且还可以识别出在回收过程中何时丢失了样品。当采样力底部的负压没有出现在恢复力与时间图表中时，就会发生这种情况。将获得的值与通过压电锥测试测得的套筒摩擦进行比较。直接简单剪切（DSS）测试和叶片剪切测试已作为参考，从样品的渗透和取回中反算无因次的皮肤摩擦系数。