Study and application of isotropic rock damage ratio strength theory
According to the strength test and strength evolution patterns of rock material on Earth,three assumptions were proposed regarding the fundamental characteristics of the strength envelope surface of rocks under triaxial compression.Based on the assumptions,a rock damage ratio expression with five empirical coefficients was established.The values of five empirical coefficients were recommended according to isotropic rock test data.The damage ratio strength criteria of two types of rocks were improved combined with the original damage ratio strength theory,and compared with the existing representative rock criteria.The results show that the predicted values of the damage ratio strength criterion are in good agreement with the experimental data,and the calculation accuracy is similar to that of other criteria.The rock damage ratio strength theory quantifies indicators of uniaxial tensile brittle failure,uniaxial and biaxial compressive crushing,and triaxial isobaric plastic flow.According to this theory,the decrement of damage ratio parameters causes a reduction in inelastic volume expansion under high hydrostatic pressure,leading to the characteristic transition of rocks toward plastic flow,which holds significant practical value.(1)This theory indicates that under the action of gravity,solid rocks in the Earth's crust undergo distinct states,transitioning from elastic-brittle to elastic-plastic and finally to plastic flow.This transition is characterized by a gradual reduction in damage ratio values.Consequently,the theory can predict the plastic flow behavior of rocks under the action of gravity.(2)The theory reveals the intrinsic factors leading to rock bursts in hard rock formations induced by stress release during high-stress tunnel excavation.It attributes this phenomenon to the inelastic volume expansion of high-pressure rock masses resulting from stress release.(3)According to this theory,it is believed that the plastic state of rocks under gravity will dissipate energy and make the mechanical energy change to heat energy.Therefore,the view of"gravity plastic energy dissipation"of the earth is introduced,pointing out that the maintenance of liquid or solid states in the mantle and the core is a consequence of high pressure,gravity,and energy dissipation,resulting in elevated temperatures.(4)Based on this theory,it is indicated that the mechanisms behind the Continental Drift and the Plate Tectonics,as well as the dynamics of earthquakes and volcanic eruptions,result from the long-term slow release of the internal energy of the Earth caused by the Earth's gravity plastic energy dissipation,and the joint action of the Earth's tidal forces,ionizing forces and the tidal forces induced by the Moon and the Sun the moon and sun's tidal forces the tidal forces of the moon and sun.The concept of"gravity plastic energy dissipation"can provide energy supplementation for magma cooling under the Kant-Laplace nebular hypothesis.
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