Immersion of loess can form compacted saturated loess or uncompacted saturated loess

and their engineering properties are significantly different. Based on the tests and data statistics of 22 loess sites in the Xi’an area

this paper systematically studied the basic physical and mechanical properties of the uncompacted saturated loess for the first time

revealed the fundamental reasons for its water-saturated weak property and large deformation due to water loss

and summarized the physical and mechanical characteristics of the uncompacted saturated loess in Xi’an area. The above research results can provide a basis for scientific research and engineering practice to strictly distinguish two types of saturated loess and formulate technical measures by classification. It is concluded that: uncompacted saturated loess is a kind of soil in which collapsible loess is not fully compacted

and macropore structure still exists in the immersion process. It is exposed in Q loess or the upper part of Q loess. It has a large void ratio

high water content

medium and high sensitivity

medium and high compressibility

low bearing capacity and strength

and is generally in soft plastic or flow plastic state. It is distributed adjacent to the compacted saturated loess

collapsible loess

and paleosol

forming a combination of soft and hard strata.