| 侧向挤压下粘土破裂实验及其地质含义 |
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| 引用本文： | 钟大赉.侧向挤压下粘土破裂实验及其地质含义[J].地质科学,1985,0(3):236-242. |
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| 作者姓名： | 钟大赉 |
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| 作者单位： | 中国科学院地质研究所 |
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| 摘 要： | 长期以来,许多学者(Chang,1984,1950;张文佑、钟嘉猷,1965;Tschlenko,1967)用粘土、松散材料或岩石做变形试验,研究破裂的形成和发展的特点,并与野外观察到的节理或破裂进行对比,取得了很大进展。诸如材料变形初期出现的吕德氏线、破裂的共轭性与褶皱构造的空间展布规律性、破裂形成过程从剪切开始到张性破裂完成(张文佑等,1983,1975),以及根据破裂的产出探讨区域构造应力场,从全球性断裂组系追溯岩石圈动力学和地壳运动力源等等。
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| 关 键 词： | , |
| 收稿时间： | 1984-06-12 |
| 修稿时间： | 1984-06-12; |
FURTHER MODELLING EXPERIMENTS ON FRACTURE DEVELOPMENT OF CLAY UNDER LATERAL COMPRESSION AND ITS GEOLOGICAL IMPLICATION |
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| Zhong Dalai.FURTHER MODELLING EXPERIMENTS ON FRACTURE DEVELOPMENT OF CLAY UNDER LATERAL COMPRESSION AND ITS GEOLOGICAL IMPLICATION[J].Chinese Journal of Geology,1985,0(3):236-242. |
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| Authors: | Zhong Dalai |
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| Institution: | Institute of Geology, Academia Sinica, Beijing |
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| Abstract: | In this paper some experimental results on clay model (8×6×4 cm3) under conditions of lateral compression in one side and free boundaries in other two sides, at room temperature, a strain rate of 10-3 sec and stresses approximately of order of 102-103 g/cm2 are present.It is commonly considered that the undeformed aggregate of clay minerals posseses apparently random disordered textures. Based on detailed study and processing by optical methods of clay aggregate, it is found that there exist at most, eight sets of inter-granular hidden symmetrical linear traces on plan as observed in piled sand grains (see in another paper).When clay model experiences lateral compression, orientations of operating shear stresses approximate any set of the hidden linear traces where appear two sets of fracture traces on surface of a model (generally called Liider’s line). Provided the magnetic North is a basic line, statistics on the measured orientations of the producing fracture traces on models compressed in different directions show mainly four preferred sets, i.e. 20-30°, 330-340°, 60-70°, 290-300°, with four subordinate sets: 0°±, 90°, 45°±315°± As deformation continues, any two sets of fracture tracesturn into fractures or tension fractures (extension shear type). An angle formed by both two fracture traces ranges between 65-75°. In most cases the direction of actual angular bisector between any generated two sets of the fracture traces is not that of operating compression. Moreover any two sets of linear traces always appear insynchronously or in the same degree, one of them making a less angle with compression is favourable to generate. The actual angle increases with increasing strain but increased angle is not more than several degrees.Meanwhile, on the model surfaces there also appears another one or two sets of linear traces bisector of which constituent an obtuse angle with compressed direction (compression-shear type). While the linear traces (extension-shear type) grow markedly in the course of progressive deformation, the former two become masked and to stop developing. It seems likely that these two types described are products of different deformation conditions. These experimental results correspond to data of field observa tions, helping to explain some characteristics of jointing a.nd mechanisms of their formation and to study the theory on stress field under incipient strain conditions. |
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| Keywords: | , |
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