复杂应力条件下地基岩石细观破坏研究  

Study on Meso-level Failure Mechanism of Rock Foundation under Complex Stress Conditions

作　　者：赵吉坤[1] 

机构地区：[1]南京农业大学工学院,南京210031

出　　处：《防灾减灾工程学报》2010年第2期141-146,共6页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(50379004);南农大工学院引进人才基金项目(RCQD08-02);南京农业大学青年科技创新基金项目(KJ09032)资助

摘　　要：为了研究复杂应力条件下的深基坑岩石细观破坏问题,本构方程采用由应变空间导出的弹塑性损伤细观力学模型,借助有限元计算方法,实现了岩石三维破裂过程的数值模拟。采用细观破坏单元网格消去法,实现了有限元模拟裂纹扩展过程;利用位移加载来实现岩石逐渐破裂过程;数值模拟灰岩单轴拉伸及压缩破坏试验、双轴拉伸破坏试验和三轴受压破坏试验,得到其非线性应力—应变曲线和不同载荷阶段弹塑性损伤破裂演化系列图像;分析细观非均匀性对岩石宏观破裂力学行为的影响。研究表明,在复杂应力条件下,随着围压增大,峰值抗压强度明显提高,塑性变形明显增大。本文研究对深基坑施工过程中预防工程事故的发生具有借鉴意义。In order to study the meso-damage mechanism of deep foundation of rock under complex stress conditions,the constitutive equations of the elasto-plastic meso-damage model,derived from the strain space micromechanics,were adopted in the finite element method to simulate numerically three-dimensional cracking process of the rock.The elimination of micro-damage elements was carried out in the finite element analysis to follow the extending process of cracks.The rock was loaded by displacement to its progressive failure process;the failure tests of the limestone,under loading cases of uni-axial tension/compression,bi-axial tension and tri-axial compression,were simulated numerically to obtain the nonlinear stress-strain curves and a series of images of cracking evolution at different stages of the loading,for the analysis of the influence of rock in-homogeneity on the macro-cracking mechanism of the rock.The results indicate that the peak values of compressive strength and the plastic deformation will increase significantly with the increment of the confining pressure.This study will be helpful to the prevention of engineering disasters in construction of deep foundations.

关 键 词：复杂应力 地基岩石 细观破坏试验 数值模拟 

分 类 号：TU452[建筑科学—岩土工程]