基于神经网络的滑坡距离预测与随机分析——以羊宝地滑坡为例

    PREDICTION AND STOCHASTIC ANALYSIS OF RAINFALL-INDUCED LANDSLIDE RUNOUT DISTANCE BASED ON NEURAL NETWORK

    • 摘要: 岩土参数存在随机性,使得滑坡的运动特征(速度、距离等)表现出不确定性,结合数值分析的蒙特卡洛模拟是研究上述问题的有效手段,但存在效率低下的问题。对此,本文在滑坡运动过程数值分析方法基础上,利用人工神经网络算法构建了用于滑坡距离快速预测的深度学习模型,结合蒙特卡洛形成了强度参数影响下滑坡滑动距离的随机分析方法。通过数值分析方法再现羊宝地滑坡的运动过程,将模拟得到的滑动距离和堆积地形与实际滑坡数据进行对比,验证了滑坡运动SPH数值模型的有效性;改变土体强度参数(内摩擦角)得到了不同强度下滑坡滑动距离,并由此建立了神经网络的训练数据集和测试数据集,利用训练后的神经网络模型预测了不同强度参数下的滑坡滑动距离,通过比较发现神经网络模型预测滑坡滑动距离具有较高的精度,能够作为滑动距离预测的代理模型。最后,在对数正态分布下生成了内摩擦角的随机样本并输入神经网络预测对应的滑坡滑动距离,研究强度参数不确定性影响下滑坡滑动距离的概率分布。结果表明,在内摩擦角符合对数正态分布的情况下,案例滑坡的滑动距离均值约为312 m,分布在288~324 m之间,为具有一定概率特征的随机变量。另外,本文建立的代理模型可以有效改善蒙特卡洛模拟效率低下的问题,能够高效地分析强度参数不确定性下滑动距离的概率分布规律,为潜在滑坡灾害隐患点中确定重点防治地段提供参考意义。

       

      Abstract: The randomness in geotechnical parameters introduces uncertainty in the dynamic characteristics(velocity, distance, etc.)of landslides. Monte-Carlo simulation(MCS)is an effective approach to account for the influence of geotechnical parameter uncertainty in landslide run-out analysis, but the large number of simulations required for accurate results leads to excessive computational time. Therefore, based on a deterministic analysis method for the process and run-out distance of flow-like landslides, a fast-predicting model of landslide run-out distance was constructed using an artificial neural network(ANN)algorithm, and a stochastic analysis method considering the uncertainty of strength parameters was established by combining Monte-Carlo simulation. Numerical analysis methods were employed to reconstruct the movement process of the Yangbaodi landslide. The simulated run-out distance and deposition morphology were compared with field observations, validating the effectiveness of the SPH numerical model for landslide simulation. Subsequently, variations in soil strength parameters(particularly the internal friction angle)were introduced to obtain run-out distances under different strength conditions, thereby establishing both training and testing datasets for the neural network. Using the trained neural network model, the landslide run-out distance under different strength parameters was predicted, and the performance of the trained model was evaluated by comparing the results with MCS, which demonstrated that the proposed stochastic model can serve as a surrogate for landslide run-out analysis. Finally, a dataset of internal friction angles was generated under a specific probability distribution as input, and the run-out distance of each sample was predicted based on the trained neural network model to discuss the probability distribution characteristics of run-out distance under strength parameter uncertainty. The results showed that when the internal friction angle conformed to a lognormal distribution, the mean run-out distance was approximately 312 m and mainly distributed between 288 m and 324 m, behaving as a random variable with specific probability characteristics. The results demonstrate that the surrogate model developed in this study effectively reduces the computational cost of Monte-Carlo simulations. Furthermore, this study investigates the probability distribution of run-out distances under strength parameter uncertainties, providing valuable references for identifying critical prevention zones in potential landslide hazard areas.

       

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