Abstract:The current "Code for Design of Highway Subgrades" and "Code for Design of Urban Road Subgrades" all draw on the relevant contents of the "Building Standards for Collapsible Loess Areas" for the ideas and principles of collapsibility treatment. Due to the high requirements of buildings on deformation and bearing capacity, the collapsibility of the foundation shall be completely treated according to the different levels of buildings and the pile foundation shall be used to traverse the entire loess layer. The building occupies a small area, and it is necessary and reasonable to treat the collapsibility of the foundation completely or to penetrate the loess layer with the pile foundation. However, for highways, urban roads, sites and other projects with large areas and low requirements for foundation deformation and bearing capacity, all collapsibility is treated in accordance with the relevant requirements of the "Building Standards for Collapsible Loess Areas", which is the exiting feasible, economical and reasonable problem. The influence of the large-thickness fill collapsibility on the project is mainly insufficient bearing capacity and overlarge deformation, which can be solved by taking some engineering measures. The problem of large-thickness collapsibility is changed into the issue of controlling the settlement and deformation of subgrade to realize the contradiction conversion and problem simplification in order to achieve the effect of solving the problems in the range of full fill thickness. Based on the large-thickness loess landfill sites, with increasing burial depth, the soil compactness will gradually increase, and with increasing burial depth, the probability of soil being wetted by water gradually decreases. The targeted engineering scheme is designed to make the treatment method, scope, standard and degree of the large-thickness fill collapsibility reasonable and economical, which are the immediate problems.
