The Application Of Gray Theory And AHP In The Pile Quality Assessment

Pile foundation is one of the commonly used form of the basis in engineeringstructures. It belonged to the underground and concealed work. A slight mistake of theconstruction prone off piles, to affect the integrity of pile and the bearing capacity of pile,which directly affected the safety of the upper structure. Pile quality test and evaluation isan necessary part to ensure the safety and reliablity of pile foundation. Evaluation results isintuitive to core drilling method using micro-damaged pile quality assessment. But thereare also strong subjective sense of responsibility and problem of larger impact to abilityabout work by testing personnel. The paper based on gray theory and analytic hierarchyprocess using core drilling method have studied pile quality test which has importantengineering applications.After careful comparison, analysis, the text selected the following parameters asevaluation factors at drilling core quality of the foundation pile: representative valuerelated compressive strength of concrete core samples,crushing length of concretepile,sediment thickness of the end of pile,strength of bearing stratum (rock compression)and thickness of bearing stratum of the five evaluation factors. Then the text studied therelationship between these factors and pile integrity assessment, and established ahierarchical model through the analytic hierarchy process.Thus the weight of evaluationfactors were established. Finally, the text worked up pile quality assessment model of thegray fixed weight clustering,and selected the pile core drilling detection of a new campusactivity center projects in Hunan Province and the second section about the first phase ofthe project of an real estate development corporation in Hengyang City as engineeringbackground, combined with the relevant norms, to assess the integrity of the pile quality.In this paper, the following findings:(1) During the process of identified the quality of the evaluation factors, the paperdivided compressive strength of the core samples into upper, middle and lowercompressive strength. The detailed classification can be applied to various types of pilesassessment.(2) The paper established analytic hierarchy model of the pile quality assessment factor. After calculation it determined the weight of the the pile quality assessment factor tomake the assessment factor quantified and visualied. It ensured the reliability of the resultsof the assessment. The study found that this method is a high degree of visual, veryconvenient to use and high precision.(3) This paper analized the two engineering examples based on gray system theoryand the analytic hierarchy process. It established four assessment standards of the pilequality. This pile quality grading standards prescribed three grades of piles is embodied intwo engineering examples. It was consistent about the conclusion through quantitativeanalysis and qualitative analysis methods of detection unit. The paper fully illustrated theeffectiveness of the proposed method.