Study on the method for determination of the maximum depth of loess collapsible under overburden pressure

Determination of the maximum depth of loess collapsible under overburden pressure is an important issue in the mechanics of loess and engineering research. The maximum depth of loess collapsible under overburden pressure is determined by testing the coefficient of collapsibility under overburden pressure, which differs from a trial pit field immersion test. Such a field test, however, is costly and therefore inadvisable for wide application in engineering practice. To identify a new laboratory test method for determination of the depth of loess collapsible under overburden pressure, loess samples were collected from the north suburb of Xi'an City, Shaanxi Province, China. Compression tests and tests of the coefficient of collapsibility (also referred to as hydrocollapse) under overburden pressure (also referred to as saturated self-weight stress) were conducted on these samples, and then their pore volumes and pore ratios were measured. From an in-depth analysis of the test results, a method was proposed for determination of the depth of loess collapsible under overburden pressure, namely the depth can be determined based on the variation of pore volumes or pore ratios with depth. The results from this paper for determination of the depth of loess collapsible under overburden pressure, which were verified by examples, are highly consistent with those from field tests. The method proposed in this paper is not only feasible but also less expensive and requires less time for test completion compared with field tests. Therefore, the method should be further investigated and considered for wider application.