大粒径碎石桩在饱和超软土地基中的应用

对广东省西江下游航道整治工程中不排水抗剪强度7~15 kPa的淤泥土地基进行了碎石桩现场试验,得出了采用大粒径碎石桩加固不排水抗剪强度小于20 kPa软土地基的合理施工控制参数:碎石填料主要粒径为5~15 cm;充盈系数为1.4~1.6;密实电流大于50A;留振时间为5~15 s.现场桩径检测、动力触探试验和复合地基大型直剪试验结果表明,采用大粒径碎石桩加固超软土地基是可行的,大粒径碎石桩对增强地基土的抗剪强度和提高软土地基承载力十分有效.

Application of large grain-size gravel piles to strengthening saturated super-soft ground

Based on field experiments on large grain-size gravel piles used for strengthening muddy ground with undrained strength 7-15kPa in the navigation channel regulation project on the lower Xijiang River of Guangdong Province,some reasonable construction parameters for soft ground strengthened with large grainsize gravel piles with undrained strength less than 20kPa were obtained,i.e.the grain-size ranging from 5?cm to 15?cm,over-charged coefficient ranging from 1.4 to 1.6,electrical current being greater than 50?A during compaction of gravel piles,and vibration time for compaction being 5-15s.Results of pile diameter inspection,drop penetration inspection,and large-scale direct shear experiments in situ show that it is feasible for strengthening of super-soft ground with large grain-size gravel piles,and that the gravel piles are much effective to intensify the shear strength of soil and improve the bearing capacity of ground.