吹填软土低位真空预压室内试验及其数值模拟

以天津滨海新区临港工业区吹填软土为试验材料，以普通型竖向排水板、改进型竖向排水板及改进型横向排水板进行室内低位真空预压试验。结果表明，利用普通型竖向排水板进行低位真空预压试验，在真空-堆载联合作用下，28 d表层土体强度达到10 kPa，但中间土体强度偏低，整体呈两边硬中间软的夹心层；以改进型竖向排水板进行低位真空预压试验，前10 d土体强度增长与普通型竖向排水板试验接近，后期土体强度增长明显比前者快，28 d表层土体强度达到12 kPa，中间土体强度略有提高，但整体均匀性仍较差；以改进型横向排水板进行低位真空预压试验，28 d表层土体强度达到11 kPa，强度增长比改进型竖向排水板试验慢，但中部土体强度和整体均匀性均优于改进型竖向排水板试验。基于上述试验成果，运用有限元模拟低位真空预压试验过程，计算沉降量和孔隙水压力并与实测数据对比，发现两种竖向排水板试验计算结果与实测数据吻合较好，改进型横向排水板试验稍差，但基本上都能反映低位真空预压过程中土体沉降量和孔隙水压力变化趋势。

Laboratory experiment and numerical simulation of soft dredger fill with low vacuum pre-compression

soft dredger fill in Tianjin Binhai New Area of Lingang industrial zone is investigated by means of common vertical drainage board, improved vertical drainage board and improved transverse drainage board to take low vacuum pre-pressing test. The low vacuum pre-pressing of common vertical drainage board showed that in 28 days the strength of surface soil is up to 10 kPa. But the strength of soil in the middle part is still low. It is hard in both sides but soft in the middle. The low vacuum pre-pressing test of improved vertical drainage board showed that in the first 10 days soil strength increasing was similar to the common vertical drainage board. Later the soil strength increased significantly faster than the common drainage vertical board, in 28 days the strength of surface soil clamed to 12 kPa, the intensity of middle part was improved, but the overall uniformity was still poor. The low vacuum pre-pressing test of improved transverse drainage board showed that in 28 days the surface soil clamed to 11 kPa. The soil strength growth was slower than the improved vertical drainage board, but the strength of middle soil and uniformity were better than the improved vertical drainage board. The above test results are analyzed using the FEM simulation software, and compared with calculated settlement and pore water pressure, the improved vertical drainage board calculation result is found in good agreement with experimental data, improved transverse drainage board is a little poor, but it can basically reflect the low vacuum preloading soil settlement and pore water pressure in the process of value.