This paper gives a description on the corresponding relationship between the injection pressure at rock breakage and that at sound emission,behavior of the frequency and amplitude of sound wave,and gives fracturing stresses corresponding to zero or negative tangential stress respectively.
This paper introduced the results of crustal stress measurement by hydraulic fracturing method within 3 vertical boreholes of a highway tunnel in east China,and the estimation formula of stress in tunnel axis' horizontal plane and the maximum tangential stress in cross section were analyzed and deduced,which was used in the tunnel's shape selection and rockburst possibility judgment.
The main reason for the above results is as following. The Q-system considers the high field stress by introducing σ-θ/σ-c,σ-θ is the maximum tangential stress(estimated from elastic theory),and σ-c the uniaxial compression strength(MPa).
THE EXPERIMENT RESEARCH OF GAS SEEPAGE LAW IN FRACTURE UNDER TANGENT STRESS
This paper presents a platform that measures the tangent stress of the elastic media using Critically Refrected Longitudinal Wave (LCR for short) based on acoustic-elasticity theory. The primary experiments are complete in general purpose stress equipment controlled by PC.
本文以声弹性理论为基础,设计并制作了一套基于TDC(Time to Digital Converter)利用LCR波(Critically Refracted Longitudinal Wave)测量弹性介质中的切向应力的实验平台,并在微机控制的万能试验机上进行了初步的实验。
Also, the experiment results prove correctness and feasibility of the methods for measuring and processing LCR wave in stress measurement. The research provides beneficial reference for the application of tangent stress measurement in elastic media from theory to practice with TDC.
According to the results, both the peak of circumferential stress and radial stress are all appeared in the corners area of the cavity die. Serious stress concentration and continuous cyclic high stress contribute to cracks initiation and growth and then lead to die failure.
The circumferential stress-strain product criterion of mixed mode brittle fracture
the circumferential stress-strain product criterion.
The coefficients in conformal mapping function are revised by iteration step by step until the largest circumferential stress in absolute value is reduced to the second largest stress.
However, the point where the compression circumferential stress zone ends is shown to be a function of the ratio of the modulii in the radial and circumferential directions whereas in Küblers' theory it was independent of the elastic constants.
Tangent moduli are derived from radial and circumferential stress-strain characteristics using non-linear curve fitting.