Abstract: Saturated loess exhibits significant physical property variations and distinctive sedimentation, and strength and deformation patterns under natural sedimentary conditions. With the combined action of water, force, and time, saturated loess undergoes a continuous transformation from an uncompacted state to a compacted state. Pressuremeter testing is a reliable in situ technique for determining the strength characteristics of saturated loess without being affected by sampling procedures. The pressuremeter curve, with three characteristic pressure values and two characteristic strength indicators, was correlated with indicators such as burial depth, initial pore ratio e, and liquid index I_L. Therefore, the key influencing factors behind saturated loess strength were obtained. Based on this, the water sensitivity parameter m_ω applicable to saturated loess was defined. The corresponding relationship between fundamental physical properties indicators and characteristic strength was established. Additionally, the criteria for distinguishing between the properties of two types of saturated loess and the principle for categorizing the strength of uncompact saturated loess were suggested. The results showed that: 1) The characteristic strength of saturated loess is influenced by several factors, including uncompact state and consistency characteristics. Thus, relying solely on a single physical property indicator would not lead to an effective and reasonable assessment of its characteristic strength. 2) The strength difference between the two types of saturated loess can be distinguished by using the critical characteristic value (m_ω = 0.5) of exponential decay of the characteristic strength of saturated loess as the dividing index. 3) The long-term development of uncompacted saturated loess can be categorized into initial, intermediate, and later stages according to water sensitivity parameter boundary (m_ω = 0.75/1.3). The corresponding characteristic strength range values for each stage have been identified.

Key words: saturated loess, pressuremeter test, mechanical evaluation method, water sensitivity parameters