含填充节理岩体的单轴压缩试验及本构模型研究

发布时间：2018-10-31 20:01

【摘要】：节理岩体是岩体工程中最常见、最重要的介质。一般情况下，节理会被软泥、沙砾等物质填充；在实际工程中，节理则会被混凝土等工程材料填充。由于节理的结构及性状对岩体的物理力学性质有着不可忽视的影响，那么考虑含填充节理岩体的本构模型则具有非常重要的实际意义。为此，本研究基于岩体结构力学观点，把岩体看作由含一定厚度填充物的节理和岩石块体组成的复合体，建立了一种考虑节理几何特征及强度参数的岩体力学模型。并采用水泥砂浆作为岩石的相似材料，对预制节理岩体进行模型试验，研究节理岩体在单轴压缩下的破坏机理，最后利用该模型分析节理对岩体强度及破坏模式的影响规律，，直观地揭示填充节理带来的影响，为相关岩体工程的设计、施工提供参考。本研究的主要工作如下：（1）对完整岩体和含填充节理岩体进行室内物理模型对比试验，研究在单轴压缩情况下，含有不同倾角、贯通度、数目、不同节理填充厚度和不同节理填充物的预制节理岩体强度及破坏模式。试验结果显示：节理岩体的破坏模式、峰值强度以及弹性模量都与节理的构造形态紧密相关。（2）对比完整岩体，对单条预制含填充物的贯通节理岩体单向加载，在一定范围内改变载荷应变率和长径比，得到岩体抗压强度和杨氏模量与应变率的量级是相关的，都随着应变率的增加有所增强；岩体破坏模式不随应变率的变化而发生改变。（3）建立反应岩体脆塑性特征的完整岩体分段本构模型，并用试验数据加以验证。然后把岩体看作由含一定厚度填充物的节理和岩石块体组成的复合体，建立一种考虑节理几何特征及强度参数的岩体力学模型，并且给出该公式关于各参数的分析和讨论。分析表明：该模型能与试验曲线符合较好，并能反映含填充节理岩体强度随节理参数变化的特性，具有一定合理性。
[Abstract]:Jointed rock mass is the most common and important medium in rock mass engineering. In general, joints are filled with soft mud, sand and gravel; in practical projects, joints are filled with engineering materials such as concrete. Since the structure and properties of joints have an important influence on the physical and mechanical properties of rock mass, it is of great practical significance to consider the constitutive model of rock mass with jointed rock mass. Therefore, based on the viewpoint of structural mechanics of rock mass, the rock mass is regarded as a complex composed of joints and rock blocks with a certain thickness of fillers, and a mechanical model of rock mass considering the geometric characteristics and strength parameters of joints is established. Using cement mortar as the similar material of rock, the model test of prefabricated jointed rock mass is carried out, and the failure mechanism of jointed rock mass under uniaxial compression is studied. Finally, the influence of joint on rock mass strength and failure mode is analyzed by using this model. The effect of filling joints is revealed intuitively, which provides reference for the design and construction of relevant rock mass engineering. The main work of this study is as follows: (1) the physical models of intact rock mass and filled jointed rock mass are compared with each other in the case of uniaxial compression. Strength and failure mode of prefabricated jointed rock mass with different joint filling thickness and different joint fillers. The results show that the failure mode, peak strength and elastic modulus of jointed rock mass are closely related to the structural morphology of joints. (2) compared with the intact rock mass, the compressive strength and Young's modulus of the rock mass are related to the strain rate and the ratio of length to diameter in a certain range by unidirectional loading of a single prefabricated jointed rock mass containing fillers, and the compressive strength and Young's modulus of the rock mass are related to the strain rate. With the increase of strain rate; The failure mode of rock mass does not change with the change of strain rate. (3) the complete piecewise constitutive model of rock mass is established and verified by experimental data. Then, the rock mass is regarded as a complex composed of joints and rock blocks with a certain thickness of fillers, and a rock mass mechanics model considering the geometric characteristics and strength parameters of joints is established, and the analysis and discussion on the parameters of the formula are given. The analysis shows that the model is in good agreement with the experimental curve and can reflect the characteristics of the strength of jointed rock mass with the parameters of joints, and it is reasonable to some extent.
【学位授予单位】：中国地质大学（北京）
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU45

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