Model test of the combined subgrade treatment by hydraulic sand fills and soil-cement mixing piles

摘要

Background The combined technology of hydraulic sand fills and soil-cement mixing piles has been widely applied to urban roads near rivers. Most of the previous studies were limited to the performance and strength of the soil-cement mixing pile and the effect of strengthening the foundation, which ignored the influence of pile layout on soil property parameters. Model test Through laboratory model tests, various working conditions of hydraulic sand placed on a composite foundation were simulated, and the effects of rolling path, standing time, rolling machinery, drainage scheme, pile spacing and pile diameter on stress distribution and consolidation drainage of composite foundation under single variable were investigated in this paper. Results and discussion The test results indicated that the increase in pile diameter can significantly increase the pile-soil pressure ratio but easily causes an excessively high porewater pressure during the rolling of the subgrade. The increase in pile spacing reduces the pile-soil pressure ratio, promotes the drainage efficiency and restricts the pile group effect. Smooth-wheel rolling has a large influence on the stress path and leads to the soil arching effect in the foundation. Conclusion Reasonable design of pile diameter, pile spacing and proper selection of rolling method are of great significance to improve the efficiency of subgrade reinforcement and reduce postconstruction settlement.