节理岩体各向异性及其强度特征分析

发布时间：2018-04-27 19:33

本文选题：节理岩体 + 各向异性　；参考：《北京交通大学》2015年硕士论文

【摘要】：摘要：岩体在其形成与存在的过程中,由于长期经受着错综复杂的改造和构造两大地质作用,从而生成了各种不同类型、不同规模的结构面,如节理、断层、片理、层理、裂隙等。受到这些结构面的交切作用,岩体形成了一种特殊的割裂结构。由此,含少数或多数不均匀分布节理的岩体在强度方面表现出了各向异性特征,且这种特征不仅受岩体本身的岩石类型控制,最主要的是受岩体中存在的节理面以及由此产生的岩体结构所控制。本文的主要研究内容是通过阅读大量参考文献资料,分别对节理岩体的各向异性特征尤其是强度的各向异性特征进行理论分析,并应用3DEC数值分析方法,从宏观上研究节理岩体强度的各向异性特性。在不同节理倾角的情况下,分别对含有一条节理、一组节理、两条相交节理、多条相交节理及在不同围压条件下的节理岩体强度的各向异性特征进行数值模拟,对节理面间距不同、节理面条数不同的节理岩体强度的各向异性特性进行研究。本文的主要研究成果归纳如下： (1)节理面的存在使得岩体的强度表现出显著的各向异性特征,在不同程度上削弱了节理岩体的抗压强度。节理面的产状、空间位置分布的不同以及围压的作用等对节理岩体强度的各向异性特征有着不同程度的影响。 (2)节理的存在使得岩体表现出各向异性特征,且随着节理条数的增加、间距的减小,单组节理岩体的强度也逐渐变小,各向异性特征越来越明显。节理间距越小,岩体强度的减小幅度越大,岩体强度的减小呈现出非线性的变化规律。 (3)围压的存在,使得节理岩体强度的各向异性特征发生了改变,随着围压的增大,节理岩体的强度有所增加,各向异性系数逐渐减小,各向异性程度减弱,节理岩体由各向异性向各向同性转化。在有围压时,围压增大,节理岩体的强度也会增大,但并不是呈线性关系的,而是在围压低时增加较快,围压高时增加比较缓慢。 (4)当岩体中含有多条相交节理时,单轴压缩时,节理岩体的强度随着节理倾角的变化而变化的幅度较小,曲线比较平缓,各项异性系数变小。说明当岩体中含有四条或以上的相交节理时,岩体的各向异性程度并不明显,可以近似当作各向同性体来对待。但由于节理的存在及其相互之间的影响,岩体的强度有了很大程度的减小。
[Abstract]:Abstract: in the process of formation and existence of rock mass, because of the complicated geological processes of transformation and structure for a long time, various types and sizes of structural planes, such as joints, faults, microstructures, bedding, have been formed. A crack, etc Due to the intersecting action of these structural planes, the rock mass formed a special split structure. As a result, rock masses with a few or most non-uniformly distributed joints exhibit anisotropic characteristics in terms of strength, and this feature is not only controlled by the rock types of the rock mass itself. The most important is controlled by the existing joints in rock mass and the resulting rock mass structure. The main research content of this paper is to analyze the anisotropic characteristics of jointed rock mass, especially the anisotropic characteristic of strength, by reading a lot of references, and apply the 3DEC numerical analysis method. The anisotropic properties of the strength of jointed rock mass are studied from macroscopic view. In the case of different dip angles of joints, the anisotropic characteristics of the strength of jointed rock mass with one joint, one set of joints, two intersecting joints, multiple intersecting joints and different confining pressures are numerically simulated. The anisotropic properties of rock mass strength with different joint surface spacing and different joints noodle number are studied. The main research results of this paper are summarized as follows: The existence of joint plane makes the strength of rock mass show obvious anisotropic character, which weakens the compressive strength of jointed rock mass to some extent. The occurrence of joint plane, the difference of spatial distribution and the effect of confining pressure have different effects on the anisotropy of the strength of jointed rock mass. (2) the existence of joints makes the rock mass exhibit anisotropic characteristics, and with the increase of the number of joints and the decrease of the spacing, the strength of single jointed rock becomes smaller and the anisotropy becomes more and more obvious. The smaller the joint spacing, the larger the decrease of rock mass strength and the nonlinear variation of rock mass strength. With the increase of confining pressure, the strength of jointed rock mass increases, the anisotropy coefficient decreases and the anisotropy degree weakens. The transformation of jointed rock mass from anisotropy to isotropy. When confining pressure increases, the strength of jointed rock mass increases, but not linearly, but increases more quickly when confining pressure is low, but slowly when confining pressure is high. 4) when there are many intersecting joints in the rock mass, the strength of the jointed rock mass changes with the change of the joint inclination angle, the curve is relatively flat, and the heterogeneity coefficient becomes smaller when uniaxial compression. It is shown that when there are four or more intersecting joints in rock mass, the anisotropy of rock mass is not obvious and can be treated as an isotropic body. However, due to the existence of joints and their mutual influence, the strength of rock mass decreases to a great extent.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

【参考文献】