我国西部地区面积约占国土总面积的71%，且山区面积占比超过了50%，地震带分布较多。长期以来，西部地区地震频发，而由地震诱发的崩塌、落石、滑坡等灾害严重危及人们的生命财产安全。地震会使得危岩体结构面的抗剪强度劣化，导致其稳定性进一步降低，从而诱发大量的危岩体失稳崩塌，开展考虑危岩体结构面震动劣化及其稳定性的研究，对于地震区的岩体工程建设与运营具有至关重要的意义。进入21世纪，我国数字近景摄影测量技术领域取得系列创新突破，推动该技术向工程实践深度渗透。因此本文以鲁甸王家坡为研究背景，采用现场测量、理论分析、数值计算等手段进行研究，主要研究内容如下：

（1）基于无人机摄影测量与三维重构技术，通过倾斜摄影和贴近摄影技术获取多角度影像，经空中三角测量、点云加密、网格划分和纹理映射流程生成三维模型；基于逆向工程提取结构面数据重构虚拟模型，提出一种类天然结构面粗糙度表征方法，并与Barton标准轮廓线进行对比验证，研究结果为后文进行结构面循环剪切数值试验提供理论支撑。

（2）基于PFC3D颗粒流方法开展结构面循环剪切数值试验，揭示其抗剪强度在循环剪切荷载作用下的劣化规律，分析循环剪切次数、剪切速率、剪切幅值、法向应力、粗糙度等因素影响下的结构面剪应力劣化特征；同时结合回归分析法，建立考虑多因素影响的结构面抗剪强度震动劣化数学模型。

（3）通过修正FLAC3D有限差分法中Interface本构模型，构建出适用于类天然结构面的本构模型，通过循环剪切数值试验，揭示接触面积对结构面抗剪强度影响规律；基于数值试验数据拟合获得结构面接触面积比、峰值剪胀角与循环次数的函数关系，结合Barton JRC-JCS模型和摩尔库伦强度准则，提出修正后粗糙度JRC表征方法，进一步构建考虑接触面积的结构面抗剪强度震动劣化模型。

（4）基于PFC3D颗粒流方法构建厘米-米级岩体结构面模型，通过循环剪切数值试验，揭示尺寸效应对结构面抗剪强度劣化的影响规律，结合上述震动劣化数学模型，引入尺寸效应系数进行修正，建立考虑结构面尺寸、循环次数等多因素影响下的结构面抗剪强度震动劣化数学模型。

（5）基于坐标投影法原理，结合修正后的结构面抗剪强度震动劣化模型，提出一种新的危岩体动力稳定性系数计算方法，并结合有限差分计算法，阐明地震波波动频率和振幅对危岩体动力稳定性系数的影响规律。

The western area of China accounts for about 71% of the total land area, and the mountainous area accounts for more than 50%, and the seismic belt is more distributed. For a long time, earthquakes happen frequently in the western region, and the disasters induced by earthquakes such as collapse, rock fall and landslide seriously endanger people's life and property safety. Earthquake will make the shear strength of the structural plane of dangerous rock mass deteriorate, resulting in further reduction of its stability, thus inducing a large number of unstable rock masses to collapse. It is of vital significance for the construction and operation of rock mass engineering in earthquake areas to carry out research considering the vibration deterioration and stability of the structural plane of dangerous rock mass. In the 21st century, China has made a series of innovative breakthroughs in the field of digital close-range photogrammetry technology, which promotes the deep penetration of this technology into engineering practice. Therefore, with Wangjiapo of Ludian as the research background, this paper adopts field measurement, theoretical analysis, numerical calculation and other means to conduct research. The main research contents are as follows:

(1) Based on UAV photogrammetry and 3D reconstruction technology, multi-angle images are obtained through oblique photography and close photography technology, and 3D models are generated through aerial triangulation, point cloud encryption, mesh division and texture mapping processes; Based on reverse engineering extraction of structural plane data and reconstruction of virtual model, a kind of natural structural plane roughness characterization method is proposed, and compared with Barton standard contours for verification. The research results provide theoretical support for the cyclic shear numerical test of structural plane in the following paper.

(2) Based on PFC3D particle flow method, the cyclic shear numerical test of structural plane was carried out to reveal the deterioration rule of its shear strength under cyclic shear load, and analyze the deterioration characteristics of structural plane shear stress under the influence of cyclic shear frequency, shear rate, shear amplitude, normal stress, roughness and other factors. At the same time, a mathematical model of vibration degradation of shear strength of structural plane considering multiple factors is established by regression analysis.

(3) By modifying the Interface constitutive model in FLAC3D finite difference method, a constitutive model suitable for natural structural plane is constructed. Cyclic shear numerical tests reveal the influence of contact area on the shear strength of structural plane; Based on the fitting of the numerical test data, the functional relationship between the contact area ratio of the structural plane, the peak shear expansion Angle and the number of cycles was obtained. Combined with the Barton JRC-JCS model and the molar Coulomb strength criterion, the modified roughness JRC characterization method was proposed to further construct the shear strength vibration deterioration model of the structural plane considering the contact area.

(4) A cm-meter rock mass structural plane model is constructed based on PFC3D particle flow method. The cyclic shear numerical test reveals the effect of size effect on the deterioration of structural plane shear strength. Combined with the above mathematical model of vibration deterioration, the size effect coefficient is introduced for correction. A mathematical model of vibration degradation of structural plane shear strength under the influence of structural plane size and number of cycles is established.

(5) Based on the principle of coordinate projection method, combined with the modified structural plane shear strength vibration deterioration model, a new calculation method for the dynamic stability coefficient of dangerous rock mass is proposed, and combined with the finite difference calculation method, the influence law of seismic wave fluctuation frequency and amplitude on the dynamic stability coefficient of dangerous rock mass is clarified.