超软土真空预压室内模型试验研究  

Study of super-soft soil vacuum preloading model test

作　　者：孙立强[1] 闫澍旺[1] 李伟[2] 吴坤标[1] 

机构地区：[1]天津大学建工学院,天津300072 [2]天津港集团有限公司,天津300072

出　　处：《岩土力学》2011年第4期984-990,共7页Rock and Soil Mechanics

基　　金：天津市科技创新专项资金项目(No.07fdzdsf02100-03)

摘　　要：随着围海造陆的发展,吹填区底面标高越来越低,吹填土厚度由原来的2 m达到现在的10 m左右,使地基加固时发生很大的压缩变形。在现场真空预压检测过程中发现土体加固后形成上面一层2～3 m的硬壳层,地表以下3～4 m土层强度增长很小。通过超软土真空预压室内模型试验发现加固后由于超软土发生很大的压缩变形,使排水板发生了很大的扭曲变形,甚至发生局部折断现象,导致排水板失效或效率降低,从而使土体加固效果欠佳。在加固土体变形基本稳定后,进行了二次插板再加固的试验,结果表明,土体的沉降进一步发展,含水率进一步降低,十字板强度进一步提高,且沿深度递减幅度大为减小,证明了第一次加固过程中由于土体发生大变形使排水板效率降低,地基不能达到预期的加固效果;采用二次插板可使吹填土产生较好的加固效果。研究成果为探索更有效地加固深厚吹填土方法提供了依据。With the development of land reclamation, the seabed elevation level becomes lower and lower and the thickness of the reclaimed soil reaches 10 m from 2 m original; so that great deformation occurs during the vacuum preloading. The strength of a soil layer about 2 m to 3 m in the foundation surface is high after the vacuum preloading in the field, but below the depth of 3 m to 4 m, the strength of soil increases little. Through super-soft soil vacuum preloading model test, it is found that the PVDs have undergone a drastic distortion because of big deformation of the soil, so that the PVDs efficiency becomes lower and the soil reinforcement is ineffective. The PVDs are installed for a second time and made secondary reinforcement to the soil after the deformation of the reinforced soil reaches stabilization. The results show that the settlement of the soil develops more; the water content of the soil can be lowered further; the vane strength can be improved more; and the diminishing rate of the vane strength along the depth is greatly reduced. It is shown that the efficiency of PVDs reduces due to the deformation in the first installation; and it can not meet the foundation design requirements; using secondary PVDs installation can have better reinforcing effect. The study results provide basis for exploring a more effective method to reinforce deep reclaimed soil.

关 键 词：超软土 真空预压 模型试验 排水板效率 二次插板 

分 类 号：TU443[建筑科学—岩土工程]