Research And Controlling On Settlement Characteristic Of Rotary Drilling Pile Considering The Bottom Sediment

Thirty years of reform and opening up, Chinese national economy has achievedrapid development, The people’s living standards improved greatly, At the same time,The construction industry of our country has developed very quickly. In the newcentury, Super high-rise building、Large span bridges、Large airport terminal buildingand some kinds of infrastructure rise abruptly like the bamboo shoots after a spring rain.In order to meet the needs of bearing capacity and settlement control of foundation forsuper high and super large building, The foundation of the business is growing, The pilefoundation is one of the most widely used form of foundation. In recent years, With thedevelopment of machinery industry and extensive use of rotary drilling rig, Rotarydrilling bored pile has occupy a space for one person in the pile foundation constructionfield. Compared with the other way of drilling, Rotary drilling rig are popular withEngineering designers and builders because of its flexible、high efficiency、Safety、environmental protection and accurate positioning. However, the problem of sedimentdefects in the construction is always a problem that Confusing the builder, Because thesediment is relatively soft, elastic modulus is smaller so that easy to be compressed,Affected the normal working performance of pile foundation seriously，Resulting inmany engineering accidents and economic loss.In this paper, Taking sediment defects of pile foundation as the breakthrough point,Based on ABAQUS finite element numerical simulation，Systematiclly analysis thesettlement characteristics of pile foundation with sediment and stress characteristics. SoI made the following points specifically:①Compared and Analysis settlement characteristics in the cases that sedimentthickness is different. Research on the impact of sediment to settlement ofcharacteristics pile foundation、The pro-potion of side friction and tip resistance、Variation of pile side friction along pile depth. In the numerical calculation,Considering sediment modulus increases gradually in the compression process.Veritably draw the load settlement curve of pile which containing sediment. This hasimportant guiding significance to study the settlement characteristics of pile withsediment.②Analysis of pile foundation settlement characteristics when the sedimentmodulus of elasticity is not the same. We can know that reinforce the sediment could reducing settlement of pile foundation. After elastic modulus of sediment reached40MPa, The load settlement curve will change little. We can know that there has a limitvalue for the sediment reinforcement measures, When the sediment modulus greaterthan this limit value, Continue to increase sediment modulus could not further reducethe settlement of pile foundation.③For the treatment of sediment defect of pile foundation, The method to add a capcould recovery capacity of pile and reducing the settlement. And then the constructionschedule would not be affected.④The pile cap can improved the pile side friction of pile top effectively，Thelarger the load, The effect of improving will be more obviously, The larger the cap size,Improved results weakened.