论文部分内容阅读
柱状节理岩体几何特征的复杂性为评价柱状节理硐室的稳定性和破坏模式带来了极大的困难,以柱内陡倾角隐节理面为例,该类型节理的存在导致节理密度增大,围岩力学性质被削弱,但同时该节理面的镶嵌特征又十分明显,增强了围岩力学性质。为进一步认识和评价柱状节理岩体几何参数对硐室稳定性的影响,在深入分析其几何分布特征的基础上,采用DDA深入研究这些几何特征对柱状节理硐室稳定性的影响,并以此为基础,对柱状节理岩体的破坏模式进行探讨。研究结果表明:(1)保持柱内近水平隐节理面的倾角不变,当柱间节理面与水平隐节理面夹角小于20°时,硐室稳定性很好;夹角为90°时,硐室稳定性最差;当柱间节理面与柱内近水平隐节理面节理倾角组合为0°和90°时,顶拱的稳定性最差。(2)节理间距对柱状节理硐室稳定性的影响主要体现在节理间距绝对值和节理间距比两方面,对于节理间距比,随着比值增大,硐室越稳定,反之亦然;对于节理间距绝对值,随着其增大,硐室越稳定,并且增加到一定程度会形成不可动块体,硐室稳定性大大增加。(3)柱状节理硐室破坏模式为:首先是部分被柱内陡倾角隐节理所切割裸露在外的小柱体首先发生张拉破坏,而后沿柱间节理面发生剪切破坏,最后沿柱内近水平隐节理面开始向临空面垮落;同时顶拱节理面在切向应力作用下也会发生一定的破坏。
The complexity of geometrical features of columnar jointed rock mass poses great difficulties for evaluating the stability and failure modes of column-shaped jointed chambers. Taking the steep dipping in-column as an example, the presence of this type of joint leads to an increase in the joint density The mechanical properties of the surrounding rock are weakened, but at the same time, the mosaic features of the joint surface are very obvious, which enhances the mechanical properties of the surrounding rock. In order to further understand and evaluate the influence of geometrical parameters of columnar jointed rock mass on the stability of chamber, based on the analysis of its geometrical distribution, the influence of these geometrical features on the stability of column-shaped jointed chamber was deeply studied by DDA. As the basis, to discuss the failure mode of columnar jointed rock mass. The results show that: (1) When the included angle between the column joint and the horizontal cryptofacial plane is less than 20 °, the stability of the chamber is good while keeping the inclination angle of the near horizontal hidden face of the column; when the included angle is 90 ° , And the stability of the chamber is the worst. The stability of the roof arch is the worst when the joint inclination between the joint column and the near horizontal column is 0 ° and 90 °. (2) The effect of joint spacing on the stability of column-shaped chambers is mainly reflected in the absolute value of joint spacing and the pitch ratio of joints. For the ratio of joint spacing, the chamber is stable as the ratio increases, and vice versa. For joints The absolute value of the spacing, as it increases, the chamber becomes more stable, and to a certain extent will form a non-movable block, chamber stability greatly increased. (3) The failure mode of columnar joint chamber is as follows: firstly, the exposed small column body is partially tensioned and destroyed by the steeply-steep hidden subduction of the column, then the shear failure occurs along the joint plane between columns and finally the column The near-horizontal cryptocompressometer began to collapse to the apron surface; at the same time, the top arch joint surface also underwent some damage under the tangential stress.