Study On Self-balanced Static Load Test Of Pile Foundation With Two-load-cell In Loess Area

In this thesis,the Self-balanced static load test with two-load-cell in loess area is carried out with the shortcomings of the traditional test method of bearing capacity of pile foundation.Through the analysis of the data,the load transfer law of the Self-balanced static load test with two-load-cell is studied.The Self-balanced static load test with two-load-cell and the static load test of anchor in the similar geological conditions are compared and analyzed.In addition,based on the formula of bearing capacity of the Self-balanced static load test with two-load-cell in collapsible loess area,the formula of bearing capacity under the condition is deduced for the case where the neutral point is located in the middle pile.The main contents of this paper are as follows:(1)By reviewing the literatures and summarizing the existing theories and results in the Self-balanced static load test,the paper introduces the law of the load transfer of the Self-balanced static load test,and determines the test scheme and the research ideas.(2)The Self-balanced static load test with two-load-cell in the collapsible loess area was carried out.By means of monitoring,collecting and analysis of the data,the load transfer law of the Self-balanced static load test with two-load-cell has been researched from three aspects: the axial force,the friction resistance and the pile end resistance.(3)Pile bottom grouting method is used in the Self-balanced test of two-load-cell.And the difference of bearing capacity between before and after grouting was studied.Through comparison and analysis,the bearing capacity of the pile before and after grouting is obtained,which provides the design reference for the pile foundation engineering in the same geological conditions.(4)This thesis is based on a Static load test of anchor pile method in the similar engineering geological conditions.The friction behavior of the two kinds of static load tests in similar loess strata and similar loading level is compared.And the relationship between the friction resistance of two kinds of static load test is obtained.(5)In this thesis,the formula of bearing capacity in the “Code for Design of Highway Bridges and Culverts”has been used to calculate the bearing capacity of the test pile.The results show that the Self-balanced test has certain reliability.(6)On the basis of the existing research results,the formula of the ultimate bearing capacity of he Self-balanced static load test with two-load-cell in loess area after wetting is summarized.In addition,the formula of ultimate bearing capacity in the condition is deduced for the case where the neutral point is located in the middle pile,which can provide reference for the determination of bearing capacity of the Self-balanced static load test with two-load-cell in loess area.