Application Research on Transient Rayleigh Technology in Pile Foundation Detection

Abstract

Detection of pile foundation is one of the most important procedures in the evaluation of pile bearing capacity and pile quality. In this paper, the application of the transient Rayleigh technology in detection of pile foundation (pile integrity, pile verticality and pile bearing capacity) have been illustrated by few examples. By using transient Rayleigh technology, the shear wave velocity of soil around pile can be tested. The pile integrity, the pile verticality and the pile bearing capacity can also be detected rapidly. Comparing with the static load test and others dynamic technologies, this method is more economical and nondestructive. Keywords—transient rayleigh technology; pile foundation detection; pile bearing capacity; share wave velocity; pile integrity ; pile verticality I. INTRODUCTION As one of the most commonly used foundation forms, pile foundation is an concealed structure. The quality of pile foundation is directly related to the operation and safety of the main structure. Once an accident happens in pile foundation, the reinforcement treatment is very difficult. Pile testing is an important measure to conduct a comprehensive evaluation on the pile bearing capacity and the pile quality. At present, the main technologies used in pile foundation detection include: the direct methods such as static load test, drill core test, and indirect methods such as high strain method, low strain method, sound wave transmission method, etc. Static load test is more effective but it takes a long time and large investment, and in some cases it is difficult to achieve. Dynamic measurement technology has been applied widely, but it is very sophisticated to interpret in theoretical basis and testing technology and application, and needs further research. Developed in the 1990' s, transient Rayleigh wave exploration technique is a new engineering and environmental geophysical method. By using the dispersion characteristics of Rayleigh wave and the relativity between wave velocity and physical mechanical character of site soil, many geological engineering problems could be solved. During the process of pile testing, transient Rayleigh wave technology could also play a very significant role. II. THEORY OF TRANSIENT RAYLEIGH WAVE TECHNOLOGY Surface waves are divided into Rayleigh and Love wave. Rayleigh wave has the strongest energy, the maximum amplitude, and the minimum frequency, making it easy to identify and measure.