Analysis Of Bearing Capacity Of Compound Foundation With Cored Cement Mixing Piles

In some areas in China,like Guangdong,Fujian,Jiangsu and Zhejiang provinces,the soft soil has features like low strength,high compressibility and low permeability.Generally,the soft roadbed treatment is conducted with the ground stabilization and deep foundation,to meet the settlement and bearing capacity requirements for the design.The half-rigidity piles like cement mixed piles,CFG piles and high-pressure rotating piles and the flexible piles like plastic drainage plates and bagged sand drains have limited improvement on the bearing capacity of soft soils;when the concrete precast piles and bored piles used as the friction piles for soft soils,the soil layer has ultimate bearing capacity on the piles,but the piles has not fully utilized its most material strength,so there is a great waste and the steel pile itself is expensive.The core entraining mixing pile for cement(referred to as “core mixing pile”)is a new-type composite pile foundation for treating soft soil roadbed.Its principle is,to add(press-in or pour into on-site)concrete core pile into the soil-cement mixing pile,and the core mixing pile is a new-type composite pile developed by China in line with the national conditions and provincial conditions.The core mixing pile integrates the technical application of concrete pile with cement mixing pile organically,plays their advantages,makes good for deficiency,and overcomes the technical problems that traditional piles cannot overcome.As opposed to the single material pile,the load transfer mechanism of the cored mixing pile is more complicated.At present,the theoretical research on the cored mixing pile has not been perfected,and there is no design specification in China.The "Technical Regulations for Adding Core Mixing Piles" YB-2007(developed by the Association of Old Scientists and Workers of Yunnan Province)is the only reference,and there are few projects applied the soft foundation treatment in Guangdong Province.In this paper,the designed Huigang Avenue Project(formerly the Public Terminal Shugang Road Phase II in Jiangmen Port High-tech Zone)is the first project that adopted the core entraining mixing pile for cement for soft foundation treatment in our unit.In the early stage when the treatment of core entraining mixing pile for cement wad designed,Wuhan Qiancheng Construction Group provided the technical support and guidance.The designed pile is about 288,803 meters,and 5 test piles of 100 meters was completed.At present,the inspection of multi-directional core entraining mixing pile for cement was completed,and the preliminary results are in line with the design requirements.In this paper,the Huigang Avenue Project(formerly the Public Terminal Shugang Road Phase II in Jiangmen Port High-tech Zone)is the basis for the actual project,and the composite foundation bearing capacity of the cored mixing piles has been analyzed with the professional software.Meanwhile,it has referred to other similar projects(Shenmao Railway DK175+193.5~237.5,DK176+337.5~487.5,DK181+997.98~DK182+200 and other road sections),to further summarize some technical features of the work method,thus providing reference to similar projects in the future.