PORTABLE APPARATUS FOR MEASURING STRESS-DISPLACEMENT RELATIONS IN PILES

THE AUTHORS RECALL THE NEED FOR MEASURING STRESS-DEFORMATION RELATIONS IN PILES IN MOST COMMON PRACTICAL CASES AND IN RESEARCH INVESTIGATIONS. THE DISADVANTAGES OF CURRENT TECHNIQUES ARE MENTIONED, AND DETAILS ARE GIVEN OF A METHOD DEVELOPED WITH THE HELP OF THE LCPC TO STUDY A 40-M LONG PILE. THE PRINCIPLE OF MEASUREMENT USED IS OUTLINED, THE MEASUREMENT BEING CARRIED OUT BY MEANS OF STRAIN GAUGES GLUED TO THE INVAR WIRE. DATA ARE PRESENTED ON THE SETTING UP OF THE TEST, THE INVAR WIRE, THE INSTALLATION OF THE EQUIPMENT AND TRIPODS. TABLES AND CURVES SHOW THE RESULTS OBTAINED (CURVES OF LATERAL FRICTION). IT IS STRESSED THAT THE EQUIPMENT DESCRIBED IS VERY ACCURATE, CAN BE FAIRLY EASILY SET UP ONCE THE PILE IS IN POSITION, AND CAN BE USED AGAIN. THIS LATTER CHARACTERISTICS ENABLES SUCCESSIVE TESTS TO BE CARRIED OUT ON ONE PILE DRIVEN IN STAGES