新吹填淤泥地基加固试验研究

Experimental Study on Improvement of Foundations with New Hydraulic Fill Muck

研究目的:新吹填淤泥地基具有含水量大、压缩性高、强度几乎为零等特点。这种比较特殊的地基处理是目前沿海地区围海造陆等工程中比较棘手的问题,为了探究这种比较特殊地基处理行之有效的方法,为沿海地区工程建设提供技术支撑,现场采用小间距排水板、土工格栅等土工合成材料结合堆载预压加固地基,设计要求地基加固后的吹填淤泥十字板强度大于10 kPa。研究结论:试验结果表明:地基加固结束时的实测沉降量达1 800 mm,地基平均固结度达95%;实测水平位移很小,在整个加载过程中,地基一直处于安全状态,说明地基处理方案是合理可行的。现场实测地基加固后的吹填淤泥十字板强度达12 kPa,吹填淤泥的土性指标得到了不同程度的改善,地基加固达到了预期的加固效果;土工格栅等土工合成材料的应用,解决了新吹填淤泥上难以直接堆载的技术难题,在类似工程中可进一步推广应用;新吹填淤泥地基单位厚度的压缩量超过200 mm/m,说明吹填淤泥地基的压缩变形属于大变形问题,理论计算时应考虑这一因素。

Research purposes： The foundation with new hydraulic fill muck is characterized by high water content, high compressibility and weak strength of about zero. At present, the treatment of such special kind of foundation is a troublesome problem in land reclamation projects in coastal areas. In order to explore the effective methods for the foundation treatment and to provide technical support for the project construction in the coastal areas, the geosynthetic materials such as drainage plates with small intervals and geogrids are employed to improve the in - situ foundation combined with surcharge pre -loading. The vane strength of the new hydraulic fill muck should be larger than 10 kPa after reinforcing the foundation according to the design requirements. Research conclusions ：The test results indicate that the observed settlement of the foundation is up to 1800 mm, and the mean consolidation degree of the foundation is 95%. The observed horizontal displacement is very small. During the whole loading process, the foundation has been in the state of safety. It is shown that the treatment scheme for the foundation is rational and feasible. The observed vane strength of the new hydraulic fill muck of the foundation reaches 12 kPa after improvement. The soil indices of the new hydraulic fill muck are improved to some extent. The anticipative efficiency is achieved for the foundation improvement. The utilization of geosynthetic materials such as geogrids successfully solves the technical problem of difficulty of direct surcharge on the new hydraulic fill muck, and it can be further popularized in similar projects. The per - unit - thickness compression amount of the foundation with new hydraulic fill muck is larger than 200 ram/m, indicating that the compressive deformation of the new hydraulic fill muck belongs to large deformation problems and it should be considered in theoretical calculations.