Study Of Bearing Behavior Of The Large Diameter Rock-socketed Pile Under Complex Stratum Condition

Along with the continuously increasing of our national economy and expanding domestic demand and speed up policy step of based construction,the development of towns construction is fast.Variously of high-rise building,ports,wharf,overpass and so on have been proposed.These buildings of requirement of based capacity and settlement become more and more strict.The characteristics of rock-socketed pile has high bearing capacity,good anti-seismic property,low settlement,weak group effects behavior?cost cheap,simple construction,which satisfy the need of these construction.So the large diameter rock-socketed pile is incessant application.When the overlaying soil is thin of the large diameter rock-socketed pile,the composition of the bearing capacity is by the side resistance of rock-socketed pile,pile tip resistance.At present,scientific development rapidly,computer promote the development of the study of the bearing capacity rock-socketed pile.But the study of the side resistance of rock-socketed pile and pile tip resistance is not enough,it need time.The paper introduce the basic characteristics of rock at first,conclude the standard of the bearing capacity of the rock-socketed pile about calculation method,introduce the working mechanism of the side resistance of rock-socketed pile,introduce the working characteristics and failure mode of the rock-socketed pile.On the theoretical basis,the indoor model test based on piles of S2# used in the Phase III of the Cuntan.The bedrock is moderately weathered mudstone in the model test.The materials are same to in-situ test.The indoor tests were selected two different kinds of rock-socketed depth which is 3.8D and 5D.By the test data,analysis of the load-settlement behavior,distribution of the side resistance of rock-socketed pile and pile tip resistance of two different kinds of rock-socketed depth.On this basis,the numerical simulation test carried out.Then mutual verification between indoor model test and the numerical simulation test.In order to mutual verification between indoor model test and the numerical simulation test and supplement the factors of the bearing capacity of the rock-socketed pile,the numerical simulation test is carried out.The numerical simulation test included depth effect,intensity of rock,pile type.It is found by analysis that depth effect existing.But the depth can't be increase infinitly to enhance the capacity of rock-socketed pile,which has certain limits.When the rock is hard,rock-socketed depth is increasedcontinuously,which can't increase the capacity.At the same time,it makes the construction difficulty and a waste of time and the economy.The best depth is the 4D in this paper.Along with the depth of rock-socketed increase,the side resistance of rock-socketed pile has been full played on the top and the peak will move down.Under the same rock-socketed depth,with the increase of load,the side resistance of rock-socketed pile will be the bimodal.As the rock-socketed depth increase,the side resistance of rock-socketed pile will be larger than the pile tip resistance.But when the rock-socketed depth reaches the 7D,the proportion of the side resistance of rock-socketed pile tends to be stable.The greater of the intensity of the bedrock that the compact force to pile is greater.Increasing the strength of the rock can increase the bearing capacity of rock-socketed pile.But it will be difficult for construction.So,it should be comprehensive consideration.