砂井联合超载预压控制软土地基路基工后沉降的优化设计

以经济效益为目标函数,软土地基路基工后沉降、沉降速率双控制指标为约束条件,建立了砂井联合超载预压处理软土地基的优化设计模型。通过一实例,采用遗传算法对控制工后沉降的3个主要设计参数:砂井间距、超载量和预压时间进行了优化求解。按优化的参数结果表明,通常情况下铺轨时加固区主固结沉降已完成,地基的工后主固结沉降大小主要取决于砂井底部的受压土层,控制的主要参数为超载量和预压时间,同时表明了作者所采用方法的有效性。

Optimizaton Design for Surcharge Precompression on Ground with Sand Drains to Control the Post-constrution of Subgrade over Soft Soils

The mathematical model of surcharge precompression on ground with sand drains is established for optimization design. In this model, economic utility is the object function; the post-construction settlement and the rate of settlement of soft subsoil are constraint conditions. A calculating program that solves the optimum values of controlling post-construction settlement is written by Genetic Algorithm. As an example, the program solves the values which include the sand drain spacing,the level of surcharge and the time of preloading. The results show: The primary consolidate settlement of the improvement zone has usually completed before the rails are installed; the quantity of primary consolidate settlement of post construction depends on the compressed strata below soft soil; the key design parameters which control the post-construction settlement are the level of surcharge and time of preloading. The model in this paper is effective to control the post- construction of the subgrade over soft soils.