In recent years, the pocket penetrometer (PPT) test has been used to measure soil compaction and has gained attention due to its simplicity, high speed, and low cost. This study aimed to predict soil strength using a regression relationship between unconfined compressive strength (UCS) and PPT. We collected 45 large soil samples from a forest district in a part of the Hyrcanian Forest. In the laboratory, soil samples were classified according to unified soil classification system. Samples were classified as either silt or clay with a low or high liquid limit. These four soil groups were, brought to four different moisture contents (14%, 25%, 31%, and 36%; n = 180 measurements). Samples were then brought to a constant dry unit weight (1.387 kg/m³). Once the samples were prepared, we measured soil compression strength using a PPT and then determined UCS. We modeled our lab results to determine if PPT could be used as a surrogate for UCS. As soil moisture content increased UCS decreased non-linearly. The behavior of silt and clay with low liquid limit plasticity were similar; likewise, the silt and clay with high liquid limit plasticity produced similar results. According to the values of Eta-squared, soil moisture is more important factor than soil type class in explaining the variance of UCS. In addition, PPT data can accurately predict soil UCS (R² = 0.98). Therefore, PPT data can be used to predict UCS of fine-grained soils with good accuracy and very low cost.

近年来，袖珍渗透仪（PPT）测试已用于测量土壤压实度，并且由于其简单，高速和低成本而受到关注。这项研究旨在利用无侧限抗压强度（UCS）和PPT之间的回归关系预测土壤强度。我们从Hyrcanian森林的一部分森林区收集了45个大型土壤样本。在实验室中，根据统一的土壤分类系统对土壤样品进行分类。样品分为低液位或高液位的淤泥或粘土。这四个土壤组的水分含量分别为四个（14％，25％，31％和36％；n  = 180个测量值）。然后使样品达到恒定的干燥单位重量（1.387 kg / m ³）。准备好样品后，我们使用PPT测量土壤的抗压强度，然后确定UCS。我们对实验室结果进行了建模，以确定PPT是否可以用作UCS的替代品。随着土壤含水量的增加，UCS呈非线性下降。液体极限塑性低的淤泥和粘土的行为相似。同样，具有高液体极限塑性的粉砂和粘土也产生了相似的结果。根据Eta平方的值，在解释UCS的方差时，土壤水分比土壤类型分类更重要。此外，PPT数据可以准确预测土壤UCS（R ²  = 0.98）。因此，PPT数据可用于以高精度和极低的成本预测细粒土壤的UCS。