高黏性新近吹填淤泥真空预压试验颗粒流宏微观分析

发布时间：2018-05-08 04:28

本文选题：新近吹填土 + 真空预压　；参考：《吉林大学学报(地球科学版)》2017年06期

【摘要】：为了从宏观和微观角度探讨颗粒组成对淤堵层形成机理和加固效果的影响规律,依托天津某新近吹填造陆工程,先进行直排式真空预压法室内模型试验,然后基于颗粒流理论和PFC2D程序,在解决模拟过程中颗粒级配和孔隙比的二维转换、排水边界的等效模拟、真空渗流场的施加等问题后,对模型进行有效的模拟计算,进而将结果推广,开展了不同颗粒组成吹填土真空预压试验的颗粒流模拟,总结了排水速率变化及颗粒运移规律。结果表明:对吹填土真空预压过程进行二维颗粒流数值模拟是有效可行的;真空预压过程中细颗粒沿渗透路径迁移,在沿途滞留,导致渗透路径变短变窄,从而形成淤堵层;对于高黏性新近吹填淤泥,在相同真空荷载作用下,黏粒质量分数越大,初期排水速率增长越快,并且随着土体不均匀系数的提高,淤堵层变得易于形成且致密,排水速率衰减越快;粉粒质量分数越大,土体孔隙率变化越均匀,尤其当粉粒质量分数大于黏粒质量分数时,真空预压加固效果有明显改善。
[Abstract]:In order to study the influence of particle composition on the formation mechanism and reinforcement effect of silt, a direct row vacuum preloading laboratory model test was carried out in Tianjin, relying on a recent land filling project in Tianjin. Then, based on the particle flow theory and PFC2D program, after solving the problems of two-dimensional transformation of particle gradation and void ratio, equivalent simulation of drainage boundary and application of vacuum seepage field, the model is simulated and calculated effectively. Then the results are generalized to simulate the particle flow in the vacuum preloading test of different particle composition of blow fill soil, and the variation of drainage rate and the law of particle migration are summarized. The results show that it is effective and feasible to simulate the two-dimension particle flow in the vacuum preloading process, and the fine particles migrate along the permeable path and stay along the road, which results in the formation of silt layer, resulting in shorter and narrower permeation path. For the newly filled silt with high viscosity, under the same vacuum load, the larger the mass fraction of clay, the faster the initial drainage rate increases, and with the increase of the uneven coefficient of soil, the silt layer becomes easy to form and compact. The faster the drainage rate decays and the larger the silt mass fraction, the more uniform the soil porosity change, especially when the silt mass fraction is larger than the clay mass fraction, the effect of vacuum preloading is obviously improved.
【作者单位】：天津大学土木工程系;天津大学滨海土木工程结构与安全教育部重点实验室;
【基金】：天津市科技兴海项目(KJXH2013-15)~~
【分类号】：TU447;TU472.33

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