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为了研究多桩型软岩复合地基的承载特性,选取了具有代表性的多桩型软岩复合地基工程,对复合地基大直径桩和CFG桩桩身轴力及桩间土应力进行了长期监测,并根据测试结果对软岩复合地基承载特性进行了分析。分析结果表明,软岩复合地基的承载特性与一般刚性桩复合地基的承载特性相似,复合地基中大直径桩与CFG桩桩身轴力随深度增加呈现先增大后减小的分布特征,在桩顶一定范围内桩侧存在负摩阻力,桩间土应力则随着与桩中心距的增加而增大。当建筑结构主体完工后,现场实测得到大直径桩桩顶平均压力约1847k N,CFG桩桩顶平均压力约105k N,复合地基表面桩间土应力在70~200k Pa之间,根据实测结果推算出的强风化泥岩中平均应力约为273k Pa。从测试分析结果中可以看出,软岩复合地基充分利用了地基中强风化泥岩的天然地基承载力,具有较好的经济性。
In order to study the bearing characteristics of multi-piles soft rock composite foundation, a representative multi-piles soft rock composite foundation project was selected to conduct long-term monitoring on the axial forces and the soil stress between the pile foundation of large diameter pile and CFG pile According to the test results, the bearing characteristics of soft rock composite foundation were analyzed. The analysis results show that the bearing characteristics of soft rock composite foundation are similar to those of common rigid pile composite foundation. The axial and axial distribution of large diameter pile and CFG pile in composite foundation firstly increase and then decrease with the increase of depth. There is negative skin friction in the pile top within a certain range of pile top, soil stress increases with the increase of pile center distance. When the main structure of the building is completed, the average pressure of the top of the large-diameter pile is about 1847kN and the average pressure of the top of the CFG pile is about 105kN. The soil stress between the piles on the surface of the composite foundation is between 70 and 200kPa. Based on the measured results The average stress in the strongly weathered mudstone is about 273 kPa. It can be seen from the test and analysis results that the soft rock composite foundation makes full use of the natural foundation bearing capacity of strong weathered mudstone in the foundation and has good economy.