统一的地基沉降速率分析方法

Unified analytical approach for foundation settlement rate

为了确定堆载预压法处理公路路基的卸载时机,提出了一类适用于欠载、等载和超载不同预压方式的沉降率分析通用表达式.然后,基于线性压缩的Terzaghi一维固结理论,提出了一种针对超载预压卸载时刻地基超静孔隙水压力回弹区和压缩区的分析方法,引入了地基残余沉降修正系数,推导出适用于欠载、超载不同预压方式的地基附加沉降量计算方法,进而得到基于线性沉降率的统一沉降率模型.结果表明:同等工后沉降下,欠载预压沉降率相对等载预压降低,预压时间延长;超载预压沉降率相对等载预压增大,预压时间缩短.最后,揭示了不同水平工后沉降和软土层厚度等对欠、超载预压沉降率分析的影响机制.

To decide the unloading time of expressway treated by the preloading method,a simple generalized expression of the ground settlement rate applied to insufficient-load preloading,equal-load preloading and surcharge preloading is presented.Then,based on the Terzaghi 1D consolidation theory of linear compressibility,a rational method for regionalization of recompression and compression in the distribution of the excess pore-water pressure under overloading-unloading is presented.With the introduction of the modified coefficient of the ground residual settlement,a calculation method of the ground additional settlement applied to insufficient-load and surcharge preloading is described.And an unified linear settlement rate model under linear settlement rate is obtained.The results show that with the same post-construction settlement,the settlement rate of insufficient-load preloading is lower than that of equal-load preloading;the time of insufficient-load preloading is longer than that of equal-load preloading;the settlement rate of surcharge preloading is higher than that of equal-load preloading;the time of surcharge preloading is shorter than that of equal-load preloading.Finally,the influence mechanism of different post-construction settlement and soft soil thickness on the settlement rate of insufficient-load preloading and surcharge preloading is analyzed.