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当压力达到大约750MPa范围内时,足够高的有效围压能使岩石发生由破裂破坏向碎裂流动破坏转变,而裂隙是两类破坏机制的必要特征。后者已由我们新得到的实验资料(即伴随三轴负载变形的同时,测量声波的传播速率和声辐射)所证实。另外,足够高的温度能使岩石经受破裂或碎裂流动破坏向塑性流动破坏转变。在后种情况中,裂隙结束了对变形和破坏的重要作用。在这种转变中,温度与应变率关系密切(应变率低时,温度较低),也与粒径关系密切(粒径较小时温度较低),尽管后种情况中强度较高)。作用于破裂和碎裂流动发生过程的应力几乎与温度无关,但与有效围压关系密切。当强度资料按照标准化温度(由熔化温度标准化)和标准化应力(由剪切模量标准化)表示时,硅质岩显示的力学性质与氧化铝非常相似。本文简短地回顾了破裂和流动机制以及与破裂-流动转变有关的可用资料,并且给出认为地壳的特定岩石中发生这种转变的载荷条件(包括围压)、温度、应变率、粒径的估算,我们试图写出与地壳力学性质有关的较全面的结论以及它对地壳性质其它方面的影响。
When the pressure reaches the range of about 750 MPa, a sufficiently high effective confining pressure can cause the rock to change from rupture failure to fragmentation flow, and the fracture is an essential feature of the two types of failure mechanisms. The latter has been confirmed by our newly obtained experimental data (that is, the measurement of acoustic wave propagation velocity and acoustic radiation along with the triaxial load deformation). In addition, a sufficiently high temperature can cause the rock to undergo fracture or fragmentation flow disruption and transition to plastic flow failure. In the latter case, the cracks end up with an important role in deformation and destruction. In this transition, the temperature is closely related to the strain rate (the temperature is lower when the strain rate is low), and it is also closely related to the particle size (the temperature is lower when the particle size is smaller), although the strength is higher in the latter case. The stress acting on the cracking and fragmentation flow process is almost independent of temperature, but is closely related to the effective confining pressure. When strength data are expressed in terms of normalized temperatures (normalized by melt temperature) and normalized stresses (normalized by shear modulus), the siliceous rocks exhibit mechanical properties very similar to those of alumina. This article briefly reviews the breakdown and flow mechanisms and the available information related to the rupture-flow transition, and gives the loading conditions (including confining pressure), temperature, strain rate, and particle size for this transition in certain rocks in the crust. For estimation, we try to write a more comprehensive conclusion about the mechanical properties of the crust and its impact on other aspects of the crust properties.