有厚度天然结构面法向循环加载变形特性研究

发布时间：2018-08-23 08:41

【摘要】：采用室内试验和理论分析相结合的方法,对有厚度天然结构面的法向循环加载变形特性进行研究。研究的天然结构面属平直稍粗型,厚2~3 mm,层间充填以岩屑为主,夹少量泥,母岩为灰岩。首先,对工程作用下的结构面应力演化过程进行梳理,并根据对结构面法向应力-闭合变形曲线特征的总结,设计了室内试验的法向荷载应力路径。其次,介绍了取样、基本物理和力学特性测试以及试件制备,分别开展了单次和多次法向加、卸载试验,并对试验曲线特征和法向变形力学机制进行分析。然后,对结构面法向循环加载本构关系进行研究,认为当法向应力在20 MPa以内时,分别采用双曲线模型和考虑修正参数的改进双曲线模型,可较好地模拟不同荷载阶段时的结构面法向应力-闭合变形关系;同时,发现当法向应力进入高应力区间后(定义大于20 MPa的应力为高应力,低于20 MPa的应力为中低应力),试验数据呈现新的特点,试验变形值与模型预测值的差距越来越大。最后,分析了造成差异的可能原因,认为在研究高应力条件下的结构面法向变形特征时,采用天然结构面试样是必要的。
[Abstract]:The deformation characteristics of natural structural planes with thickness under normal cyclic loading are studied by means of laboratory tests and theoretical analysis. Secondly, sampling, testing of basic physical and mechanical properties and preparation of specimens are introduced. Single and multiple normal loading and unloading tests are carried out, and the characteristics of test curves and normal deformation mechanics machine are analyzed. Then, the normal cyclic loading constitutive relation of the structural plane is studied. It is concluded that the normal stress-closed deformation relation of the structural plane at different loading stages can be well simulated by using the hyperbolic model and the modified hyperbolic model considering the modified parameters when the normal stress is less than 20 MPa. After the force enters the high stress range (defined as the stress greater than 20 MPa is high stress, the stress lower than 20 MPa is medium and low stress), the test data show new characteristics, and the gap between the test deformation value and the model predicted value is wider and wider. It is necessary to adopt the natural structure interview.
【作者单位】：长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金项目(No.51209021,No.51539002,No.51379022)~~
【分类号】：TU458

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