Experimental Study On Bearing Capacity Of Single Pile Tested By Reverse Self Balance Method

At present,the test methods of pile foundation bearing capacity mainly include traditional static load test and self balanced pile test method.The former is the most credible approach to confirm the bearing capacity of pile.but,owing to the restriction of construction plant and pile weight,this method is difficult to meet the test of bearing capacity of special site and large tonnage foundation pile.Although the latter does not need the reaction frame or stacking load of static load method,it is a breakthrough However,when the self balance test results are applied,it is necessary to introduce a conversion coefficient of positive and negative friction which is hard to decide precisely,which will affect the accuracy of the detection results.In order to adapt the needs of project construction and advance the detection technique of foundation pile bearing capacity,this paper studies the feasibility and operability of the reverse self balanced test method for single pile bearing capacity through numerical simulation and indoor model test.This article state in detail the basic principle and operation method of the reverse self balanced pile test method,analyzes the load transfer law of rock socketed pile and non rock socketed pile,and expounds the pile-soil action mechanism in the reverse self balanced pile test method.Based on the engineering pile,the finite element model of the reverse self balanced pile test method to test the bearing capacity of rock socketed pile is established,and the feasibility of the reverse self balanced pile test method is studied.Taking the finite element model as the prototype,according to a certain similarity ratio,the indoor model test of the single pile bearing capacity by the reverse self-balancing pile test method is designed,and the ultimate bearing capacity of the pile determined by the conventional classical parameter method is compared,which verifies the operability of the reverse self-balancing pile test method in detecting the bearing capacity of the pile foundation.The results are as follows(1)The mechanism of the reverse self balanced pile test method is analyzed.It is shown that the reverse self balance pile test method can overcome the problem of the conversion of positive and negative friction resistance in the self balanced pile test method.The reverse self balance pile test method can obtain the compressive bearing capacity and the uplift bearing capacity of the pile.(2)The calculation results show that it is feasible to confirm the bearing capacity of pile foundation by using the reverse self-balancing pile test method.(3)The indoor model experiment of reverse self balanced pile testing is founded and contrast between the ultimate bearing capacity of pile calculated by conventional parameter method,and The results show that the consistency is good,which indicates that the reverse self balanced pile test method has strong operability in the application of pile foundation bearing capacity detection.