柔性荷载下粉喷桩复合地基承载特性试验研究

开展了粉喷桩复合地基承载性能试验，实测了柔性荷载下桩、土应力，探讨了复合地基中桩土应力比及其变化规律。研究表明，粉喷桩复合地基载荷-沉降曲线一般表现为缓变型；粉喷桩复合地基承载力宜按相对沉降法取相对沉降比为0.01所对应的压力。由于砂垫层的流动补偿作用，柔性荷载下桩土应力比随荷载的增加变化较为平缓，在复合地基承载力基本值附近桩土应力比变化范围为1.73～6.83，平均值为3.20。

Experimental study on bearing characteristics of dry jet mixing pile composite ground under flexible load

The bearing characteristics of dry jet mixing pile composite ground are investigated.The stresses on pile and soil and their variation under flexible load have been measured;and pile-soil stress ratio of composite ground with DJM pile under flexible load and its variation with the load have been studied.The investigation indicates that the static loading test curves of composite ground are of gradually varied shape;it is feasible that load corresponding to relative settlement ratio s/b =0.01 is taken as basic bearing capacity value of composite ground according to relative settlement method.Because of running compensation effect of cushion,pile-soil stress ratio n changes comparatively gentle with load.Pile-soil stress ratio n changes about 1.73-6.83;its average value is 3.20.