Comparative Study The Characteristics Between Composite Foundation Treated With Rammed Soil-cement Piles With And Without Side Constrain

The bearing mechanism and working characteristics of composite foundation treated with flexibility pile are realized and mastered by people gradually, and the technic of composite foundation treated with flexibility pile have being popularized continuously. In order to meet a higher demand of bearing capacity and lower settlement, the study start with basing on analyzing the status of soil-cement pile and composite foundation at home and abroad, put forward a new technique of treated foundation with additional side constrain in flexibility pile composite foundation. Large-scale model testing in the laboratory and numerical simulating were carried out, set composite foundation with tammed soil-cement piles as an example.Comparative model test of static load were carried out between composite foundation treated with rammed soil-cement piles with and without side constrain under flexibility load. A relatively comprehensive study on the working behavior between composite foundation with rammed soil-cement piles with and without side constrain. The results show that, the composite foundation bearing capacity can be increased and settlement is decreased as side constrain pile can limit soft soil squeeze out when treat soft soil foundation of rammed soil-cement piles.Comparative test on working behavior of long-term load were carried out between composite foundation with rammed soil-cement piles with and without side constrain under flexibility load. The effect on working behavior of composite foundation under long-term load were studied. The results show that, the time of settlement while it tends stability be shortened by2/3and the final settlement will reduce1/2-1/3when treamed with rammed soil-cement piles composite foundation with side constrain than it as the same condition without side constrain. The time of settlement tend stability can effectively shorten at flexible pile composite foundation, and drainage consolidate velocity of soft soil can be accelerated, the settlement after constructed can be large reduced when treated soft soil with side constrain.The finite element models of composite foundation with rammed soil-cement piles with side constrain or without under flexibility load were established. The numerical simulation results show that, the influence scope of settlement and settlement value of rammed soil-cement pile composite foundation with side constrain were smaller than without side constrain.The results derived from finite element simulation of composite foundation are the final results when the settlement of composite foundation is stable. The more shorter of consolidation time when it is stable, the more closer of the results between don’t considering the consolidation effect and the test result. Therefore, we must consider consolidation effect to the results before the settlement get to stable when the soft soil with large moisture content and need long time to consolidate.