Papers by Keyword: Major Principal Stress

Abstract: Chengmenshan open pit has been constructed to be the biggest copper pit in China. The slope designed with empirical rock mass rating and engineering analogy needs reinvestigation and evaluation for its overall stability. With help of SURPAC, the topographic contour of the mine was converted into surface model. Then the geological information of the mine was embedded into the numerical solid model by NURBS treatment of the core loggings. Through overall stability analysis with MIDAS, it was found that there was no obvious failure in the pit with the current design. But the major principal stress at the north especially the north-east corner of the pit tended to be high, so the width of the bench below the high stress region is suggested to be widened for possible collapse in this region. And field observation should be carried out in the region. Once evident slip or collapse happens, anchor and netting structures should be used. At the same time, high shear stress zones were revealed at the south-east of the outside limit of the pit. More planting is suggested to avoid soil creep or even landslides in heavy rain.

Abstract: The present paper investigates interactions between a main crack and a surrounding layer of crazing patterns. Analysis of the stress field distribution as well as the energy induced during these interactions is based on the resolution of some equations along with appropriate boundary conditions and the use of a numerical approach. The effect of amplification and shielding on the resulting stress field is shown through a study of mode I Stress Intensity Factor (SIF). Besides, to quantify the effects of this damage on the main crack, it is shown that the Energy Release Rate (ERR) is defined as being a superposition of the energy released due to the linear propagation of the main crack as well as the one due to the translational change in the growth of the damage. It is also proven that crazes closer to the main crack dominate the resulting interaction effect and reflect an anti-shielding of the damage while a reduction constitutes a material toughness.

Abstract: In this study, interactions between a main crack and a surrounding layer of crazing patterns are considered. Analysis of the stress field distribution induced during these interactions is based on the resolution of some differential equations along with appropriate boundary conditions and the use of a numerical approach. These equations are established according to Mohr’s criteria since the craze growth occurs along directions parallel to the minor principal stress axis. Because this damage can constitute an important toughening mechanism, the mode I stress intensity factor (SIF) is employed to quantify the effects on a crack of the damage consisting of crazing patterns. It is proven, herein, that crazes closer to the main crack dominate the resulting interaction effect and reflect an antishielding of the damage while a reduction constitutes a material toughness.