Capabilities of auxiliary techniques for low strain impact testing of piles foundations

Abstract

Introduction. An increase in the complexity of tasks arising from the quality control of geotechnical structures ultimately increases the role of indirect methods as part of the survey set. Low strain impact testing of piles length and integrity is currently one of the most common non-destructive geophysical methods used in the state diagnostics of foundations. The capabilities and limitations of the method are associated with the peculiarities of its basic theoretical model describing the propagation of elastic waves in a thin rod. In this regard, specialists often have recourse to the auxiliary techniques of field research.Aim. To inform test engineers, designers and employees of supervisory organizations about the potential of auxiliary methods for the low strain impact quality control of pile foundations.Methods and materials. The features of the theoretical model of the low strain impact pile quality control, as well as the associated capabilities and limitations of the method are described. The auxiliary methods of data collection and analysis were used for the survey of pile foundations, including those in the composition of existing structures.Results. The results of the work are represented by additional information obtained about the foundations surveyed using the auxiliary methods of data collection and analysis. An alternative arrangement of sensors relative to the surveyed structure was used for determining the depth of piles in the composition of grade beam footings and existing structures. The common shot point profiling (ultra-seismic method) was used to assess the velocity of rod wave propagation in the body of the structure. The options of data presentation in the parallel seismic method were used to demonstrate its potential for the quality control of foundation concrete.Conclusion. The auxiliary methods of data collection and analysis used in the low strain impact survey of pile foundations can significantly increase the reliability of conclusions about the depth and integrity of a structural material.