利用有效应力铲求解静止土压力系数研究

摘要

Research purposes:The coefficient of earth pressure at rest is an important mechanical index of ground soil.The key to determine the coefficient of earth pressure at rest is to obtain the horizontal effective stress of ground soil in situ.Through this study,an effective stress spade test for simultaneous testing of soil horizontal total stress and pore water pressure is developed,and the method of determining the coefficient of earth pressure at rest by the effective stress spade test is proposed.Research conclusions:(1) The total horizontal stress measured by the effective stress spade test is the average value along the shovel face distribution,and the pore water pressure at the center surface of the spade face is the minimum value of the distribution of the excess pore pressure.(2) With the dissipation of pore water pressure,the soil around the spade surface is drained and consolidated,which leads to the increase of the effective stress.(3) Compared with other testing techniques,the consistency and correlation of the coefficient of earth pressure at rest calculated by penetration value of the effective stress spade test are better.%研究目的:静止土压力系数是地基土的一项重要的力学指标,确定静止土压力系数的关键是获取地基土原位状态下的水平有效应力.通过本研究,研制可同步测试土的水平总应力和孑隙水压力的有效应力铲,并拟建立有效应力铲试验确定静止土压力系数的方法.研究结论:(1)有效应力铲试验测定的水平总应力是沿铲面分布的平均值,铲面中心点处孔压测量值是超孔压分布的最小值;(2)随着孔隙水压力消散,铲面周围土体产生排水固结,导致有效应力增大;(3)与其他试验手段相比,采用有效应力铲试验贯入值计算的静止土压力系数一致性和相关性较好.