Research on collapsibility of a loess site in Pakistan

The loess of an area in Pakistan is the Quaternary Holocene alluvium. The study and existing geological data in this area are relatively few, and special research is needed. In order to determine the distribution and collapsibility of the lo-ess, based on the construction distribution of the loess site, undisturbed soil sample was selected at the typical location. The unconfined compression strength tests and compressive tests were carried out. The structural characteristics of loess were quantitatively described by structural index. The self-weight collapsible coefficient and collapsible coefficient of loess were determined, the self-weight settlement and the total settlement were calculated and compared with the standard method. The experimental results show that the dry density and the collapsible coefficient(p=200 kPa) of the loess are almost unchanged with the depth, and the natural moisture content increases as a whole. The structural index of loess decreases exponentially with the increase of comprehensive physical quantity. The compressive yield stress p_sc decreases with the increase of mois-ture content, and it has a linear relationship with the structural index. The loess site was determined as a self-weight collapsible site. The correction coefficient is suggested to be less than 1, and the grade of foundation collapsible is Ⅲ.