Experimental research on the static characteristics of the composite foundation of the different typed piles

摘要

Based on the idea of optimization design of pile type, the three kinds of the typical pile type are selected, which containing flexibility pile (e.g. rammed cement-soil pile is for short RCSP), rigid pile (e.g. cement –flyash-gravel pile is for short CFGP) and loose material pile (e.g. sand-gravel pile is for short SGP). The seven kinds of the composite foundation are designed, which are CFGP, CSP and GP composite foundation, CFG long pile and sand-gravel short pile( for short CFGLP-GSP), CFG long pile and CFG short pile(for short CFGLP-CFGSP), CFG long-short pile and rammed cement-soil short pile (for short CFGLP-RCSP) , and CFG core pile rammed cement-soil loop pile (for short CFGCP-RCSP)combined composite foundation. The in-site load tests show that under the equal pile radius and equal pile space, the load-settlement curves of three kinds of single-pile composite foundation is nonlinear obviously, and the nonlinear degree of four kinds of combined composite foundation pile settlement decreases, CFGLP-CSSP and CFGCP-CSLP is closed to linear relation. Compared the computational and experimental results, the six kinds of composite foundation bearing capacity calculation values except for SGP composite foundation, are greater than the experimental value, composite foundation bearing capacity experimental value is near to low limit of the computation value. From the point of stress distribution, the degree of stress concentration of the SGP composite foundation is lowest among the three single-typed composite foundation , and CFGCP-CSLP composite foundation is lowest among the four combined composite foundation.