Study on the strength characteristics of core pile-cemented soil interface of jet grouting jacked composite piles
Jet grouting jacked composite pile has a high bearing capacity of a single pile,reasonable force-bearing,can be in the existing building reinforcement and renovation project of the low clearance conditions of construction advantages.The rotary static pressure composite pile has double layer load transfer mode,core pile-cemented soil interface and cemented soil-pile surrounding soil interface are the key factors to control the bearing characteristics and destruction mode of jet grouting jacked composite pile.For this feature,study on the core pile-cemented soil interface of jet grouting jacked composite pile.Through the strength test of the cemented soil test block,the influence of cement content,cement ratio and age on unrestricted compressive strength is verified,Through the interface strength characteristic test,it is proved that the lateral resistance of core pile-soil interface is related to the unlimited compressive strength of cemented soil,and the bonding coefficient of steel pipe-cemented soil interface and concrete-cemented soil interface is obtained.The test shows that the compressive strength of cemented soil is controlled by the amount of cement and water content,and decreases with the increasing water ash ratio.For cemented soil with different water-cement ratios,there is an optimal cement mix.There is an approximate linear relationship between the ultimate side resistance of the core pile-cemented soil interface and the cemented soil strength,and the average bond coefficient of the steel pipe-cemented soil interface is 6.66％.The core pile-cemented soil interface goes through the elastic stage,brittle failure stage and shear slip stage in the loading process.
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