The Experimental Research For The Pile Length In Site By Low Strain Dynamic Testing

This paper presents two new experimental methods—Double wave crestsmethod and Time differential method, in which for the testing of pile quality indynamic low strain method, by analyzing the application of stress wave theory to thepiles and on the demands of project quality control. This method improves traditionaltesting method to a certain extent, thus getting more relevance information of pile,pile length in-site can be satisfactory determined without the construction pile lengthand wave velocity. This paper puts forward a calculation method for the pile length,and verifies the feasibility of this method through testing three pre-cast concrete pilesand three bored piles in-site.Finally, this paper provides a method which brings BP neural networks intoascertaining the ultrasonic velocity by analyzing and summing up the correlativitybetween the stress wave velocity and ultrasonic wave velocity. This method canrealize the transfer of wave velocity by making use of the relationship between twokinds of wave velocity, in order to getting the stress wave velocity closing to theactual value, and finally achieve the purpose of determining the pile length. With theuse of the neural networks function piece in MATALB, we can realize this methodand verify by information of a project.