水泥改良土地层人工冻结温度场的特性

提出了一种改进的二次曲线轮廓度误差的评定方法。以最小二乘曲线的焦点坐标作为中心划分正方形网格，在其中按一定规则设定标志点，若标志点配对拟合曲线计算所得轮廓度误差过大就将其剔除。然后在误差较小的区域进一步细分网格并配对拟合曲线，再以多次迭代运算的方法最终求得最小条件法下的轮廓度误差值。该方法搜索速度快，计算精度高，适用于任意平面二次曲线的轮廓度误差评定，辅以MATLAB软件实现误差求解的可视化，最后实例证明该算法的可靠性。

Characteristics of artificial freezing temperature field in cement-soil layer

This study was based on the secondary freezing reinforcement project of cement soil layer of a connected aisle of Fuzhou Metro Line 2. Field measurement was conducted of the temperature of the frozen saline and the soil temperature within the main influence scope of freezing during the active freezing period and maintenance freezing period. Through the analysis of monitoring data, the cooling law of frozen saline and soil body in the freezing process was obtained; the heat exchange process in each cooling stage was explored; the differences of cooling law of soil in different positions were summarized. The freezing effect is evaluated by calculating the intersection time, effective thickness and average temperature of the freezing wall. The feasibility of using artificial freezing method in cement soil layer is verified, which can provide reference for similar projects.