基于土料强度参数随机-模糊性的土石坝坝坡稳定风险研究

Slope instability is one of the most common failure mode of earth-rock dam. At present, slope stability analysis of earth-rock dam is decided by anti-sliding stability coefficient which is evaluated and deduced by deterministic slope soil parameters, so this decision always has a sudden change , and the risk of slope instability still exists even when the safety coefficient meets the design standard requirement. This study establish Dam Slope Instability Risk Model based on reliability theory, regarding dam slope shear equilibrium as limit state, where considering spatial variability and fuzziness of soil strength parameters through a number of soil tests: the former is described as a Markov random process, and the latter can be represented by membership function and confidence interval. With the comparison between the traditional slope risk model, risk model on soil spatial variability and risk model on both spatial variability and fuzziness, reveal the influence law of variability, fuzziness and some other uncertainty of soil strength parameters on slope instability probability, evaluate the acceptable range of risk combined with engineering examples. The study will change the judgment of slope stability of earth-rock dam to acceptable risk evaluation and provide ideas to the evaluation and decision-making of dam safety under risk management mode.

坝坡失稳是土石坝最常见的破坏形式之一。目前土石坝坝坡稳定主要是建立在筑坝土料参数确定的基础上，得出坝坡抗滑稳定安全系数并进行评价，这种决策方式具有一定的突变性，且即使安全系数符合规范要求的坝坡依然存在失稳的风险。本研究基于可靠度理论，以土石坝坝坡剪切平衡为极限状态，在土料强度参数试验的基础上，以马尔科夫随机过程表征参数的随机空间变异性，以隶属度函数和置信区间表征参数的模糊性，建立考虑坝坡土料强度参数空间变异性、模糊性的坝坡失稳风险模型。对比基于土性参数传统随机性、土性参数空间变异性以及随机变异性与模糊性同时考虑三种条件下土石坝的边坡稳定的风险模型，揭示土石坝坝料强度参数不确定性对坝坡失稳概率的影响规律，结合工程实例评价风险的可接受范围。本研究将坝坡稳定的确定性判断转变为可接受风险评价，为风险管理模式下评价和决策土石坝安全提供思路。

坝坡失稳是土石坝最常见的破坏形式之一。目前土石坝坝坡稳定主要是建立在筑坝土料参数确定的基础上，得出坝坡抗滑稳定安全系数并进行评价，这种决策方式具有一定的突变性，且即使安全系数符合规范要求的坝坡依然存在失稳的风险。本研究基于可靠度理论，以土石坝坝坡剪切平衡为极限状态，在土料强度参数试验的基础上，以马尔科夫随机过程表征参数的随机空间变异性，以隶属度函数和置信区间表征参数的模糊性，建立考虑坝坡土料强度参数空间变异性、模糊性的坝坡失稳风险模型。对比基于土性参数传统随机性、土性参数空间变异性以及随机变异性与模糊性同时考虑三种条件下土石坝的边坡稳定的风险模型，揭示土石坝坝料强度参数不确定性对坝坡失稳概率的影响规律，结合工程实例评价风险的可接受范围。本研究将坝坡稳定的确定性判断转变为可接受风险评价，为风险管理模式下评价和决策土石坝安全提供思路。