Abstract:

Combining with the stress characteristics of the foundation soil, the soil force was analyzed for finding the improved effect on the separated foundation bearing capacity of lateral fill. Establishing the calculation model and algorithm, the general formulation of separated foundation bearing capacity considering lateral fill was deduced. Then under direction of similarity theory, five model tests were designed to simulate the foundation deformation of silty clay in whole loading process. The pressure-settlement curves were drew and the foundation bearing capacity under lateral fill height of 0 m,4 m,8 m,12 m,16 m were measured. Test results showed that with the fill height increasing the bearing capacity increased significantly, it had been reached 885 kPa when the fill height was 12 m. But the growth was nonlinear, it firstly increased from 18.42% to 36.11% and then reduced to 3.39%. At last the bearing capacity reached 915 kPa while fill height reached 16m. Meanwhile the errors between the calculated results and measured by model test were almost less than 10%, so the algorithm was feasible. The conclusion is that the lateral fill is advantageous for improve the foundation bearing capacity and reduce project cost significantly when the settlement of the culverts foundation satisfied the design request, with the lateral fill increasing, the rate of the improvement first increases and then decreases, at last it tends to 915 kPa when fill height reached 16 m.

Key words: lateral fill, separated foundation, foundation bearing capacity, model test, critical point