The Combination Prediction Method For Ultimate Bearing Capacity Of Single Pile

The ultimate bearing capacity of single pile is one of the basic parameters in pile foundation engineering design.Its accuracy directly affects the safety and economy of Engineering construction.Static load test is considered to be the most direct and reliable method to determine the ultimate bearing capacity of single pile.However,due to limited conditions,static load test can not be loaded to the pile foundation to reach the failure state in many cases.At present,many achievements have been made in the prediction method of ultimate bearing capacity of single pile based on static load test data,but there are some shortcomings in the prediction process,such as not considering the influence of old and new static load test data and being easily disturbed by elastic stage data.Therefore,in view of the limitations of the existing prediction methods of ultimate bearing capacity,this paper will put forward improvement ideas from two perspectives on the basis of curve fitting analysis: one is to improve the prediction accuracy of single model;the other is to carry out combined prediction based on comprehensive evaluation of multiple single models.Firstly,aiming at the different validity of predicting ultimate bearing capacity under the difference between old and new static load test data,a new objective error function is established by introducing the weight function and the solving principle of single pile ultimate bearing capacity prediction model,and a solution is put forward to the disadvantageous influence of abnormal data on prediction effect which may exist in the actual test data,on the basis of which a static load test is proposed.A new method for predicting the curve ultimate bearing capacity of pile foundation based on the test data is proposed,and a bearing capacity prediction model considering the influence of the old and new degree of static load test data on the prediction effect of pile foundation bearing capacity is established.Then,considering the limitation of the reasonable degree of the single prediction model for the bearing capacity of single pile,this paper introduces the idea of combination prediction,and introduces the concept of drift degree to establish the evaluation method of measuring the reasonable degree of the prediction model.On this basis,it puts forward the method of selecting the better single model and determining the weight distribution;and aiming at the problem of how to choose the data reasonably in the elastic stage,the drift degree is used.Concepts,the evaluation method of reasonable degree of discarding elastic stage data is established to obtain the most reasonable selection scheme,and then the combined prediction method of ultimate bearing capacity of single pile is established.Finally,through the calculation and analysis of specific engineering examples,the forecasting results of the forecasting method established in this paper are compared with the ` the rationality and feasibility of the forecasting method in this paper.