Experimental Study On Triaxial Loading And Acoustic Emission Characteristics Of Limestone In Shanyang County

There are a large number of high-steep rocky slopes in mountainous roads in China,and large-scale collapse disasters have a great impact on them,which seriously threatens people’s safety and daily life.At present,there is no monitoring and early warning technology for acoustic emission in China,which is popularly applied to the high and steep dangerous slopes of S203 in Shanyang County,Shaanxi Province.The acoustic emission phenomenon of limestone deformation and expansion,however,reflects the process of releasing elastic vibration waves when the internal fractures,holes,and other weak interlayer rupture,and has important theoretical reference value for the experimental study of acoustic emission characteristics of limestone.The mechanical and acoustic emission characteristics of limestone were studied through theoretical research,field investigation,laboratory tests,data analysis and Matlab reprocessing.Acoustic emission technology was used to focus on the triaxial loading and acoustic emission monitoring tests on the 10 limestones collected at the site.It is possible to simulate the failure mechanism of dangerous rock on the high and steep slopes of the highway and to implement a more difficult scenario for on-site monitoring.The main research results obtained in this paper are described as follows:(1)Based on several high and steep cutting slopes in S203 of Shanyang County,the surrounding engineering geology and influencing factors were identified,and 10 limestone steep slopes were assessed for danger.Two analyses were found.High and steep dangerous rock slopes are extremely dangerous.Among them,qualitative analysis was made on five different types of dangerous rock slopes,and it was found that they are more likely to collapse.Stability analysis and calculations were made on the dangerous rock masses.By selecting parameters and comprehensive analysis,we obtained The real need for monitoring and early warning of two high and steep slopes.(2)Determined the ultimate stress value,peak load,acoustic emission energy,and ringing count of limestone through failure through rupture,indicating that acoustic emission characteristics can be used as a parameter indicator for monitoring and early warning of dangerous rock on high and steep slopes.Through the five complete and five fissured limestone specimens drilled on the S203 slope site,the indoor triaxial loading and acoustic emission monitoring tests were performed.The descriptions before and after the rupture of limestone with different fracture damages were summarized.The data of their mechanics and three acoustic emission parameters during the loading failure process are statistically analyzed,and the mechanisms of their mechanical and acoustic emission parameters over time are comprehensively analyzed.(3)Based on the wavelet toolbox and program preparation in Matlab,the acoustic emission waveform data of limestone peak rupture was reprocessed,and it was indicated that there was a delay in the abrupt change of acoustic emission waveform of limestone.Wavelet and wavelet packet analysis methods were used to perform waveform transformation and inverse transformation on the collected acoustic emission waveform data.The method of threshold denoising was used to obtain an effective limestone mutation waveform curve.In addition,the acoustic emission waveform of limestone peak rupture was identified by mutation,and the characteristics of the trend of acoustic emission waveforms were analyzed.Through laboratory research on triaxial loading and acoustic emission characteristics of limestone,it can provide reference for the monitoring,assessment and early warning applications of S203 high-steep slope in Shanyang County.