No abstract

A mud pump is one of the three key components of a drilling site, and its lifetime and reliability are related to safety and cost. The fluid end is the most easily damaged part of the mud pump. To ensure normal operation, the fault modes of the fluid end need to be effectively identified. This study proposes to employ acoustic emission technique to identify the fault modes of mud pump fluid end, including valve disk leakage, spring break, and piston wear. The analysis method of parameters and waveforms of the acoustic emission signals are both used in this article. The characteristic parameters of the acoustic emission signals are combined with grey relational analysis to identify the fault modes with small samples; wavelet packet signal processing technique is applied to decompose and reconstruct the obtained acoustic emission signal waveforms and extract the energy of each frequency range to construct the eigenvectors which are input into the genetic algorithm with back propagation neural network for fault diagnosis. The results show that the fault modes under small samples can be effectively identified by combining the characteristic parameters and the grey relational analysis; the frequency range energy eigenvalue can be extracted using the method of wavelet packet signal processing, and the genetic algorithm with back propagation neural network is of better convergence than that of the back propagation neural network.

Fine silty sand layer is one of the common weak strata. It is easy to deform suddenly and induce accidents under the external load due to its loose structure and poor self-stability. To improve the stability of the strata in engineering construction, the grouting is usually used for antiseepage reinforcement in the fine silty sand layer. is paper presents the basic principle of the sonic vibration grouting, develops the experimental device and the simulated stratum condition, mixes the acidic water glass for engineering application, and carries out the experimental study on the sonic vibration grouting. e results show that the effect of the exciting force on the sonic vibration grouting is not obvious, and the vibration duration has a greater influence on it. With the increase of the vibration duration, the grouting diffusion distance is enlarging gradually and stabilizes eventually at a certain value. e vibration frequency has the greatest impact on the grouting. e grouting effect is the best when the vibration frequency is close to the natural frequency of the fine silty sand. e grouting diffusion distance is getting smaller, which means the grouting effect is becoming worse, when the vibration frequency is far away from the natural frequency of the stratum. e grouting effect in the fine silty sand layer can be improved effectively by vibration technology using the sonic vibration grouting which has excellent effect in engineering application. is paper lays a foundation for the further study on mechanism and engineering application of the sonic vibration grouting.