Experimental Study Of Limestones, Kaiser Effect And Its Application In The Ground Stress Field

Ground stress is an important engineering technology index which involves theengineering stability evaluation and plays an important role in all kinds of engineeringproblems. The traditional geo-stress measurements have great defects, such as expensive,difficult to operate, consuming large amounts of manpower and material resources. ThroughRock mechanics experiment,the Kaiser effect have discussed in order to judge the stress leveland its distribution law.The Kaiser effect of measuring ground stress as a new measurementmethod is widely accepted, and this method is more and more applicative in projects.This article is based on Xin’an coal mine in Hua Ning Group, and in this paper, Kaisereffect and the period of quiet phenomenon will be discussed in theory. Besides, a new way toget the Kaiser point by improving the experimental sampling frequency is obtained. Uniaxialcompression tests about the limestone excavated from Xin’an coal mine were executed onSAW-2000electro-hydraulic servo-controlled rock mechanics testing system. Conventionalmechanical parameters, such as the phenomenon of the Kaiser point of limestone and its quietperiod were found. Based on the mechanical parameters, maximum principal stress andmaximum principal stress direction were calculated, and then the experimental data forANSYS simulation to demonstrate the correctness of the trial data. The experimental resultsshow that in the-380region, the stress level is36MPa and the maximum principal stressdirection is NW86.8o. ANSYS simulation shows the stress level is34MPa and the maximumprincipal stress direction is NW91o. These two results demonstrate the errors between thestress level and the maximum principal stress direction is5%and1.1%respectively.Therelationship between quiet phenomenon and prediction of rock were discussed, When therock mass strength reach into the92.8%of the ultimate strength, the rock mass stabilityshould be monitored.Comprehensive analysises of the data, Arrangement of underground chambers and thesurrounding rock control will be discussed, this method have same practical values...