强震作用下岩质高边坡稳定的三维矢量分析法

Earthquake-induced landslides are common second disasters triggered by earthquakes，whether the slope is stable or not under strong earthquakes directly relates to the success of the project, the safety of the lives and property of the people. This project aims to study on the stability of high rock slope under strong earthquakes. Firstly, according to real spatial distribution of structures, the mechanical model of high rock slope can be established and the real stress distribution of slope would be obtained, the force condition of potential sliding body can be analyzed and the preferred sliding direction would be studied on the basis of the vector charactistics of force and the friction theory. Thus, three-dimensional vector analysis method can be established. Without iterations and the hypothesis of strength reduction, this method is clear in its physics and its calculating process is very simple. Secondly, the dynamic characristics of strong earthquakes can be considered and the three-dimensional time history dynamic stress state of high rock slope can be analyzed, then the time history curve of factors of safety with the proposed method would be obtained, and the evaluation index of high rock slope stability can be studied under strong earthquakes based on the reliability theory of slope,and this is verified by shaking teble test. Finally,this proposed method is applied in a high rock slope. The results of the proposed method are compared with those of the traditional calculating methods, which would verify the reliability of the proposed method. The approval of this proposal may provide a new idea for dynamic stability of high rock slope and have great theoretic benefits and practical engineering value for the protection of high rock slope.

地震诱发的滑坡是一种常见的地震次生地质灾害，边坡稳定与否直接关系到工程的成败和人民生命财产的安全。本项目围绕强震作用下岩质高边坡的稳定性问题开展研究。首先，建立能够反映主要结构面空间分布的岩质边坡力学模型，获取坡体的三维应力状态，分析潜在滑体的受力特征，并根据力的矢量特点和摩擦理论研究其优势滑动方向，从而建立三维矢量分析法。该方法物理力学意义明确，计算简单，无需迭代。其次，考虑强震荷载的动态时程特征，分析岩质边坡各时刻的三维空间应力分布，采用矢量分析法获得安全系数时程曲线，结合边坡可靠度理论建立强震作用下岩质高边坡动力稳定性的评价指标，并通过室内振动台模型试验进行试验验证。最后，将该方法应用于具体岩质高边坡工程，并与常规计算方法进行对比分析。研究成果可为边坡动力稳定性评价提供一种新思路，对岩质高边坡的防护具有重要的理论意义和工程价值。

针对目前我国工程建设中遇到的高陡岩质边坡安全这一关键技术难点，本项目开展了强震作用下三维岩质高边坡动力稳定性研究，研究成果具有重大的理论意义和工程价值。本项目基于坡体的真实应力状态，在二维矢量和法基础上建立了三维边坡稳定性分析的矢量和分析法，提出了岩质边坡动力稳定的矢量和分析法并通过室内试验进行了验证，最后给出了边坡体动力破坏的定量评价指标，并将该方法应用于西藏樟木典型边坡工程中，为边坡动力稳定性分析提供了一个新的途径和方法。项目主要的研究成果如下：（1）地震荷载下二维边坡动力矢量和分析法的数值实现及应用。考虑地震荷载的动态时程特征，获取了坡体在动态过程中应力分布特征，根据边坡矢量和法力学模型，求解了坡体的动态稳定性安全系数时程曲线，并进行了算例和工程实例应用。（2）基于有限元法建立了三维边坡静力矢量和分析计算模型。提出了三维边坡整体下滑方向的求解算法，推导了三维矢量和法安全系数的计算公式，建立了三维边坡矢量和分析法的计算模型，并通过经典算例进行了合理性验证及工程实例应用。（3）地震荷载下三维动力矢量和分析方法数值实现及试验验证。通过三维动力有限元法，采用无限元边界，数值实现了三维岩质边坡动力矢量和法的分析过程，在此基础上，通过三维经典算例和室内振动台试验，研究了坡体动力荷载作用下稳定性及破坏特征。（4）边坡动力矢量和分析定量评价指标。结合边坡动力安全系数时程曲线和边坡可靠度理论，基于安全系数的均值、标准差和可靠度指标提出了边坡动力稳定性的定量评价指标，该指标可为实际边坡工程的动力稳定性提供技术性参考。（5）在上述边坡动力矢量和法研究的基础上，将该方法应用到西藏樟木典型堆积体边坡工程中，综合评价了该坡体在地震荷载作用下的稳定性。本项目研究成果为边(滑)坡工程动力破坏特征及稳定性评价提供理论指导和技术支撑。