Evaluation of Reaction Piles Effect on Test Piles in Static Load Testing Using Three-Dimensional Numerical Analysis

摘要

Static load testing includes the direct measurement of pile head displacements when a physical test load is applied. It is known as the most fundamental form of pile load testing and generally considered as a benchmark for pile performance assessment. During static load testing, the load is commonly applied using a hydraulic jack acting against a reaction beam, which is restrained by an anchorage system. The anchorage system may be in the form of cable anchors or reaction piles installed into the ground to provide tension resistance. In this paper, PLAXIS 3D software incorporating elastic-perfectly-plastic Mohr-Coulomb and hardening-soil constitutive models is initially used to simulate a real static load test conducted in stiff overconsolidated clay. Then, in order to assess the effect of the reaction system on the test results, a similar model using the hardening-soil model is simulated. In the three-dimensional model, different numbers of reaction piles, identical to the test pile, are located in different distances from the test pile. Subsequently, the influences of spacing, length, diameter of reaction piles, and type of reaction piles on the load-displacement behavior of test piles are assessed. This paper can provide insight to practicing civil engineers on how to design the loading systems for static pile load tests. static load testing; reaction piles; hardening-soil model; numerical modeling; overconsolidated clay