不同构造层次岩石变形准则的融合与发展  

The union of various rock deformation criteria at different structural levels and its further development

作　　者：侯泉林 程南南 石梦岩 卢茜 HOU QuanLin;CHENG NanNan;SHI MengYan;LU Xi(Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences;College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beifing 100049, China 2. Department of Earth Seienees , Western University, 1151 Richmond Street, London, Ontarioa N6A 3K7, Canada)

机构地区：[1]中国科学院计算地球动力学重点实验室,中国科学院大学地球与行星科学学院,北京100049 [2]Department of Earth Sciences,Western University,1151 Richmond Street,London,Ontarioa N6A 3K7

出　　处：《岩石学报》2018年第6期1792-1800,共9页Acta Petrologica Sinica

基　　金：国家重点研发计划深地资源勘查开采重点专项(2016YFC0600401)资助

摘　　要：岩石变形准则对于构造地质学、工程安全等方面均具有重要的理论价值与实践意义。经典的岩石脆性变形(破裂)准则包括屈特加准则(水平直线型包络线)、库伦准则(斜直线型和抛物线型包络线)、格里菲斯准则(抛物线型包络线)等。近年来最大有效力矩准则在野外韧性剪切带观测与理论计算中都得到了广泛应用,逐渐成为岩石韧性变形的重要准则。然而,这些变形准则在应用过程中还存在一些问题,如有些准则在理论上无法解释、彼此不相协调,最大有效力矩准则在摩尔图解中尚无对应的包络线,部分准则边界条件和应用范围不清等。本文针对这些问题,结合野外实际情况和理论分析,取得了如下认识:(1)水平直线型屈特加准则在地质过程中无法实现。(2)提出了最大有效力矩准则的包络线方程为τ=-0.35(σ_n-σ_d),在摩尔图解中为一条反倾斜直线型包络线;进而将脆性变形的格里菲斯准则和库伦准则与韧性变形的最大有效力矩准则统一表述于应力摩尔图解中,使各准则彼此协调和融合。(3)初步明确了各变形准则的适用条件及所对应的构造层次:张性应力存在的构造环境(包括地壳浅表层次、水力压裂等人为张性应力环境),格里菲斯准则比较合适,以张性破裂(θ=～0°)和张剪性破裂(θ=0°～30°)为主;上地壳在一般情况下(3个主应力均为挤压应力),斜直线型库伦准则更为合适,以锐夹角共轭剪破裂(θ=～30°)为主;随着深度的增加,在中地壳,抛物线型库伦准则较合适,以锐夹角脆韧性剪切变形带(θ=30°～45°)为主;进入下地壳及以下,最大有效力矩准则更合适,以钝夹角韧性剪切变形带(θ=～55°)为主。实际地质作用过程中影响岩石变形的因素更为复杂多样,应具体问题具体分析,不能简单地对号入座。The study of rock deformation criteria, including brittle and ductile deformation criteria, has important theoretical value and practical significance for structural geology and engineering safety. The classic brittle deformation （failure） criteria include Tresca criterion, Coulomb criterion and Griffith criterion, which are horizontal line, oblique line or parabola, and parabola envelope in Mohr diagram, respectively. In recent years the maximum effective moment （MEM） criterion has become one important ductile deformation criteria, which is supported by increasingly solid evidence from both observed examples in nature and laboratory experiments. However, we find that it is unfeasible for applying these criteria to actual geological practices. For instance, there are no reasonable explanations for some of the criteria in theory; though the MEM criterion is well functioned in explaining the origin of obtuse conjugate angle （usually ~110°）, it is not yet resolved for the accurately corresponding envelope of MEM criterion in Mohr diagram; the applicable limitations of some criteria are unclear which make certain contradictions. Combining with field practices and theoretical analyses, we hold that：（1） It cannot be done for the Tresca criterion with horizontal envelope （the equation is τ=τ0, τ0 is the cohesive strength） in geological processes. Because in compressive regime, the normal stress is positive （σn〉0） on the planes in θ=45° direction （θ is the angle between the maximum principal stress σ1 and the potential share planes）, the failures will not form in this direction until the shear stress overcomes not only cohesive strength but also internal friction of the rock. Namely the shear stress cannot make rocks fracturing when it just achieves cohesive strength. The case of conjugate shear failures with 90° in the field is merely a coincidence, which is more likely to be the end tip of Coulomb criterion with parabola envelope tending to be horizontal in high confining press

关 键 词：岩石破裂准则 最大有效力矩准则 摩尔包络线 构造层次 微观变形机制 

分 类 号：P542[天文地球—构造地质学]