基于DDA的岩质边坡稳定性评价方法

岩质边坡的稳定性主要受节理、裂隙等结构面控制,基于连续介质的边坡稳定性分析方法已不适用。为此,将节理岩体非连续变形分析(DDA)方法与强度折减法相结合,提出基于DDA的复杂岩质边坡稳定性分析方法,并给出强度折减策略和安全系数确定依据。通过单滑块直线滑面和多滑块圆弧滑面两个算例,并与理论解和条分法计算结果进行对比,验证该方法的准确性和有效性。以河南洛宁抽水蓄能电站场内公路岩质边坡为例,应用该方法分析不同折减系数下边坡的变形演化过程和位移演化规律,并确定边坡的安全系数。结果表明,在降雨及爆破开挖扰动影响下,边坡破坏首先发生在坡脚,然后逐渐发展到坡顶,与现场调查及监测结果较为吻合。该方法可为复杂岩质边坡稳定性评价提供一种新的研究途径。

The Method Evaluating the Stability of Rock Slope Based on DDA

The stability of rock slope is mainly controlled by the discontinuous structural faces, so the continuum-based analysis method of slope stability is not suitable to evaluate the rock slope. To this end, by introducing the strength reduction theory into the DDA method, a discontinuous method evaluating the stability of rock slope is proposed. In addition, the strength reduction strategy and the basis for determining the safety factor are given. Then, the safety factors of a single block sliding on a inclined plane and multiple blocks sliding on a circular surface are calculated and compared with the theoretical values and the slice method results, respectively. The good agreement indicates the accuracy and validity of the proposed method. Taking the rock slope of the road in the site of Luoning pumped storage power station in Henan Province as an example, the deformation evolution process and displacement evolution law of slope under different reduction coefficients are analyzed based on the proposed method, and the safety factor of slope is determined. The results showed that under the influence of rainfall and blasting excavation disturbance, the slope failure first occurs at the foot of the slope, and then gradually develops to the top of the slope, which is consistent with the field investigation and monitoring results.The proposed method can provide a new research approach for the stability evaluation of complex rock slope.