Experimental Research on Deep Collapsible Loess Foundation Treatment by Dynamic Compaction under Super High Fill

Abstract

Taking one foundation project as an example, a series of tests are carried out to study the dynamic compaction parameters and its effects on the deep collapsible loess foundation under super high fill in Lvliang region. Analyses are made on the average settlement of each test area before and after dynamic compaction and on the regularity of the main physical and mechanical indexes of soil. At the energy levels of 2000 kN•m, 3000kN•m and 6000kN•m, the main parameters are gained, such as the effective reinforcement depth, the centre distance of tamping points , the standard of stopping ramming, and the optimal ramming number; hence, the empirical formula of the effective reinforcement depth of dynamic compaction. The results of the tests show that the deep collapsible loess foundation in Lvliang region can be effectively reinforced by dynamic compaction, that the stability of foundation is good, and that the loess collapse in the reinforced range is eliminated basically. Moreover, after dynamic compaction above the energy levels of 2000 kN•m, the eigenvalue of the bearing capacity of collapsible loess foundation in Lvliang can reach over 300kPa; the deformation modulus of foundation soil is more than 25MPa. Therefore, the results of the tests can provide a reference for the design and construction of projects of the same kind; it can also provide a reliable basis for relevant norms and standards.