迁安石英岩脆延性转变特征及定量判据

FROM BRITTLE TO DUCTILE TRANSITION BEHAVIOR AND QUANTITATIVE CRITERION OF QIANAN QUARTZITE

本文在0—700MPa围压、室温800℃温度条件下,对一组迁安石英岩变形破坏实验研究,提出了不同条件下地壳岩石两种可能的脆延性转变机制,并阐明了脆延性转变中岩石力学性质、强度特性和失稳型式的变化。文章指出,岩石脆延性转变的实质是岩石破裂前各种机制产生的非弹性变形组分迅速增加,造成破裂贯通点偏离线性变形段,使岩石表现出延性行为。因此,依据破裂贯通点偏离线弹性变形段的程度,就可以定量判别岩石的变形性质,确定岩石脆延性转变的条件。

The experiments carried out on Qianan quartzite deformation at temeratures up to 800℃ and pressures up to 700 MPa show that there are two fundamental transitional phases in rock properties during the course of changing from brittle to ductile. Here, a detail description is given about the mechanical properties, strength and failure patterns of the rock and emphasis is laid on that the essence of transition of rocks from brittle to ductile is related to the increase in elastic deformation before the final failure reaches. The increase of nonelastic deformation component will make the major fracture point on the stress-strain curve deviate from the initial linear stage of elastic deformation and permit the rock gradually going into ductile deformation field. On the basis of the value of deviation we can judge the behavior of rock deformation and give a quantitative criterion for determining the transition of the rock from brittle to ductile.