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About 60% of the territory of the Russian Federation is covered by permafrost. Additionally, a large share of the country’s mineral and hydrocarbon deposits are located in the Arctic. Climate change that has been happening over the past few decades has had a serious impact on the conditions in which permafrost soils are found. Changes in temperatures in permafrost regions, along with the human impact from mining and processing, have led to an increase in accidents caused by the degradation of permafrost foundations. In this situation, timely detection of the degradation of permafrost foundations plays a pivotal role in ensuring the safe operation of buildings and structures. This article contains a theoretical review and describes the results of an experimental study of whether it is possible to use acoustic testing in solving problems associated with monitoring the state of permafrost foundations. In the course of the study, the relationships between the acoustic characteristics and the deformation and strength characteristics of permafrost soils were analysed. The results of the study made it possible to draw a preliminary conclusion that acoustic testing can be used to solve problems associated with condition monitoring of permafrost foundations.

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The difficulties with the application of low strain integrity testing for evaluating the length of driven precast piles of two sections justify the need for new data acquisition and analysis techniques. The standard time domain analysis of the recorded signals may not allow for distinguishing the desired responses from a pile toe and a splice. In this paper, we propose the use of a set of hammers of different weights and tip materials that will provide various sensitivities of the test to a pile splice. To further analyze the collected data, we study the distributions of phase angles obtained using complex continuous wavelet transform. The characteristic phase shifts that distribute from higher to lower frequencies can be interpreted as responses from a pile toe and a splice. To verify the proposed approaches, a series of numerical simulations were performed using the finite element method for the driven pile models with the different properties of a splice zone. Numerical simulation results show that the pile splices are clearly identified when using the shorter input pulses which can be generated by light hammers with a hard head material. The total length of a simulated pile with a 1 mm air gap between sections was undetectable by standard data analysis approaches and was evaluated when analyzing the wavelet phase angle distributions. Numerically validated data acquisition and analysis techniques were applied to field data analysis and allowed us to confidently identify the length of two-section piles grouped with a pile cap.