地震地质 ›› 2014, Vol. 36 ›› Issue (3): 845-861.DOI: 10.3969/j.issn.0253-4967.2014.03.023

• 构造物理与地震机理 • 上一篇    下一篇

实验室尺度典型断层系统破坏、前兆及粘滑过程数值模拟

王学滨1,2,3, 马冰2, 吕家庆2   

  1. 1. 中国地震局地质研究所, 地震动力学国家重点实验室, 北京 100029;
    2. 辽宁工程技术大学力学与工程学院, 阜新 123000;
    3. 辽宁工程技术大学计算力学研究所, 阜新 123000
  • 收稿日期:2014-03-26 修回日期:2014-09-10 出版日期:2014-09-30 发布日期:2014-09-30
  • 作者简介:王学滨|男|1975年生|2006年在辽宁工程技术大学获得工程力学专业博士学位|2009—2012年在中国地震局地质研究所做博士后研究|教授|主要从事岩石力学、计算力学等方面的研究|电话:0418-3350924|E-mail:wxbbb@ 263.net。
  • 基金资助:

    地震动力学国家重点实验室开放课题(LED2014B03)、高等学校博士学科点专项科研基金(20132121110006)和国家自然科学基金(51374122)共同资助

NUMERICAL SIMULATION OF FAILURES, PRECURSORS AND STICK-SLIP PROCESSES FOR TYPICAL FAULT STRUCTURES AT A LABORATORY SCALE

WANG Xue-bin1,2,3, MA Bing2, LV Jia-qing2   

  1. 1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2. College of Mechanics and Engineering, Liaoning Technical University, Fuxin 123000, China;
    3. Institute of Computational Mechanics, Liaoning Technical University, Fuxin 123000, China
  • Received:2014-03-26 Revised:2014-09-10 Online:2014-09-30 Published:2014-09-30

摘要:

尽管实验室尺度典型断层模型的基本物理、力学参数已知,载荷、边界条件明确,但其变形、破坏、前兆及稳定性的综合数值模拟并不容易。实验室尺度模型的数值模拟可为大尺度模型的模拟积累经验,并提供某些必要的技术基础。文中主要从数值模型的角度,评述实验室尺度模型中引入非均质性和粘滑过程模拟的各种方法,着重介绍了2种模型:断层-岩石系统的非均质应变弱化模型和摩擦强化-摩擦弱化模型。在第1种模型中,提出利用事件的频次-能量释放关系的斜率绝对值的不同演变规律评价断层的不同应力状态。在挤压雁列区贯通过程中,剪切应变降对岩石破裂具有更为灵敏的指示作用,可能比声发射更为有效。在第2种模型中,通过控制内摩擦角在粘着和滑动两阶段不同的演变规律实现断层粘滑过程的模拟。尽管在提出的摩擦强化-摩擦弱化模型中未引入速度,但由于对节点的运动方程进行求解,所以节点速度在粘着和滑动两阶段将发生变化。指出以下需要进一步研究的问题:1)亟待发展适于地质体材料变形、破坏及运动整个过程模拟的计算力学模型;2)亟待发展复杂断层系统中断层稳定性的可靠判别方法;3)亟待发展动力学方程的高效求解方法。

关键词: 实验室尺度模型, 破坏, 粘滑, 前兆, 摩擦, 剪切应变, 雁列构造

Abstract:

For typical faults at a laboratory scale, with basically known physical and mechanical parameters and specific loading and boundary conditions, the integrative numerical simulation of their deformations, failures and stabilities is difficult. The numerical simulation at a laboratory scale can lay a foundation for that at a large scale, and can provide some necessary technical conditions. In this paper, from the viewpoint of numerical modeling, we reviewed the methods of introducing heterogeneities and reproducing stick-slip processes at a laboratory scale. Two models are specially emphasized: the heterogeneous strain-softening model with faults and rock blocks, and the frictional hardening and frictional softening model. In the first model, to assess the state of stress for faults, we present the method to calculate the absolute value of the slope of the relation between frequency of events and released energy. During the jog failure for the compressive echelon faults, some quantities related to large shear strain drops are particularly sensitive indicators for rock fractures, and can be more effective than acoustic emissions. In the second model, the internal friction angle follows different laws at the stick and slip stages. Though no velocity is introduced in the model, the velocity changes at the stick and slip stages because of solving the motion equations. Three problems worthy of further investigation are pointed out. Firstly, a computational model is needed to reproduce the entire process of geomaterials: deformation, failure and motion. Secondly, a reliable method to assess the stability of faults for a complex system is necessary. Finally, high efficient solving algorithm for the motion equations is especially needed.

Key words: laboratory-scale model, failure, stick-slip, precursor, friction, shear strain, echelon fault

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