Experimental Research On Vertical Load Of Rubberized Cement-Soil Piles Composite Foundation

Rubberlized cement-soil is made of soil, cement and rubber powder mix with water, after a series of chemical reaction formed a new soil-cement complexes. Cement-soil composite foundation is wide apply in foundation treatment of newly-built or rebuild buildings, ports and highway. Due to soil-cement piles'applied feature, it's affected by surrounding environment factors such as underground water contains erosive ions (ex: SO42- , Cl- etc.), sanitary sewage and seawater, thus reduce the strength of cement-soil and influence the durability. Rubber is a polymer elastic material indissolvable in nature, it has the characteristics of corrosion resistance, therefore add amount of rubber powder in cement-soil pile and form rubber cement-soil pile to resist erosion ions. At present, there is not any research of rubber cement-soil pile composite foundation.This paper systematically studied load-bearing characteristics of rubber cement-soil pile composite foundation affected by rubber powder content and cushion'thickness,(The loading properties of the same strength single-pile composite foundation ,the same strength four piles composite foundation and their loading properties'comparison. ) Main achievements and conclusions as follow:Experimental research on load-bearing characteristics of single pile composite foundation affected by rubber powder content: rubber powder content significantly affected to load-bearing c of composite foundation. With the increase of the rubber powder content, loading ratio between pile and soil of composite foundation, stress ratio between pile and soil are both decrease; settlement of composite foundation is increase.Experimental research on load-bearing characteristics of single pile composite foundation affected by cushion's thickness: cushion's thickness has important impact on load-bearing and deformation characteristics of composite foundation. With the increase of cushion's thickness, the proportion of load sharing by pile is decrease gradually, while the proportion of load sharing by soil is increase, characteristics appear as with the increase of cushion's thickness, stress ratio between pile and soil is decrease. On the other hand, cushion can adjust the capacity of pile soil deformation, with the increase of cushion's thickness, settlement of composite foundation is decrease.Experimental research on the same strength single-pile composite foundation and the same strength four piles composite foundation):under vertical load, pile shaft and soil jointly bear. But, material performance of pile shaft is good, so load sharing of pile shaft is large than soil, stress concentration effect of pile shaft is obvious. Load sharing of four piles composite foundation is far large than single pile composite foundation. When use single pile composite foundation, stress ratio between pile and soil is 1.8-9.0, and stress ratio between pile and soil of four piles composite foundation is 12-38. This shows that, when adopts multiple pile composite foundation to treatment foundation soil, the bearing capacity of pile body are more conducive to play, meanwhile the requirement of pile body is also higher. Load-settlement relation curves of single pile composite foundation show slow-varying and sharply down, curves change are relevant to amount of rubber powder admixture. Especially, curves of four pile composite foundation show feature of stepped, it's reflects that the load-bearing property of every pile in is complex and non-synchronous.