Research On Bearing Characteristics Of H-section Of Variable Cross Shaped Pile

In Practical project, in addition to the majority of piles of foundation which is bear vertical load from the superstructure, but often to withstand the lateral loads, the instantaneous horizontal force from earthquake and normal braking state of transport. Horizontal forces and bending moments of piles of bridge come from wind,wave, tidal water and so on. these constant load and live load of high-rise buildings, bridges, heavy industrial plants, offshore oil platforms can not be ignored in calculations in pile design under normal circumstances.In order to meet the requirements of composite bearing characteristics of piles,A new type of pile was proposed in this paper which becomes H-section of variable cross Shaped Pile. currently The study of H-section of variable cross Shaped Pile under vertical or horizontal load,especially Research on pile groups is less.Based on scale model tests indoor and ABAQUS finite element analysis to discuss and analysis In-depth of characteristic of the variable section Shaped Pile and Pile groups.The main contents are as follows:(1) Using method of reduced scale model test, experiment in door of single Tapered Shaped pile under static load has been implemented, based on the reduced scale model test and had using software of ABAQUS to conduct simulation analysis of model tests and comparing the results of numerical simulation with that of reduced scale model test,which has reached conclusion of that variable cross-shaped pile have a higher axial bearing properties.In addition on the basis of the distribution of axial force and lateral friction on the pile. Calculation empirical formula of tapered Shaped pile about bearing Capacity having been proposed. And effective length of the variable cross-shaped pile has been determined.(2) The test of H-section of variable cross Shaped Pile under unidirectional cyclic loading method calm load has been carried out, direction experimental research have also been done respectively on the direction of vertical flange and web,compare the curve of load-displacement of numerical analysis with that of test results under vertical load, make sure that it is effective to the model parameters.The simulation analysis experiment of pile under loads on different directions rely on ABAQUS finite element software have been conducted, pile them in the moment, the displacement of the pile, the pile of earth pressure, soil traits uplift work laws the difference in depth. The results showed that: H-section of variable cross Shaped Pile with better levels of spindle orientation on bearing capacity.(3) using the accumulated parameters of experiment and numerical simulation to study bearing performance of H-section of variable cross Shaped Pile group by ABAQUS, base on a quarter model and simulate nine pile cap pile foundation to study the vertical load-bearing characteristics.By analyzing pile of different position distribution of axial force, side friction resistance and best pile space of H-section cross-section variable group pile, Q- S response of pile cap, Proportion of pile group and the load, Soil displacement nephogram between piles. obtained results as follow :1.when the load of pile group beyond 1.109 k N, the clamping effect on upper soil between piles begin to decrease,and the upper side friction resistance increases, almost no change happen on lower part of pile, influence scope of side friction is different in different positions.2.When the settlement reach more than 4% times of pile diameter, the proportion of pile caps is gradually increasing with the increase of load, but ratio of pile group decreases, and the last ratio load sharing tends to be stable.3. distribution of load of pile top in different position is uneven, when load is small, presents the center pile load is greater than the side of pile and load of the side of pile is greater than that of angle pile, all piles has a tendency to converge along with the load increasing. After reach the limit load, when the load of Angle pile begin to decline, but trend of side of pile and the center is on the rise.4.Optimal pile spacing range of H-section cross-section variable group pile is between5 d and 6 d(d as long lengths of pile head).5.Vertical settlement between pile soil increase gradually decreases with depth when pile caps is under low load condition, compression deformation is mainly distributed in bottom reach to a third range of the pile length. As the load increasing, soil around of pile head is no longer sinking with piles and pile caps, the clamping effect begin to decrease, compression deformation of upper soil between piles is increases.