考虑全生命周期的露天矿边坡时效稳定性分析

基于开挖岩体蠕变劣化效应对露天矿高边坡稳定性的影响，提出了全生命周期内边坡的稳定性模型。引入岩石强度劣化理论，推导了时间效应下安全系数的计算公式。考虑锚索的预应力损失和边坡蠕变现象，建立了预应力损失条件下边坡安全系数的表达式，分析了时间因素和锚索预应力损失对边坡稳定性的影响规律。以大孤山西井边坡为例，借助FLAC3D内置的FISH语言把劣化理论嵌入到强度折减法中，利用改进的强度折减法计算了边坡的时效安全系数。结果表明:岩石强度随时间延长呈“L”型劣化，使得蠕变型边坡的安全系数低于只考虑开挖的情况，与实际工程更加吻合，受锚索预应力损失的影响已加固边坡仍有失稳的风险。比选了4种锚索的加固调控方案，在满足全生命周期内安全生产的前提下，获得了经济效益最优的方案。

Time-dependent stability analysis of open-pit slope considering life-cycle

Based on the influence of excavation and creep degradation on the stability of high slopes in open-pit, a stability model of slopes in life-cycle is proposed. By introducing the deterioration theory of rock strength, the calculation formula of safety factor under time effect is derived. Considering the prestress loss of anchor cable and the creep phenomenon of slope, the expression of safety factor of creep slope under prestress loss condition is established. Forthemore, the influence law of time factor of slope and prestress loss of anchor cable on slope is discussed. Taking Dagushan Xijing slope as an example, the decay theory is embedded into the strength reduction method with the help of the flash language built in the FLAC3D, and the improved strength reduction method is used to calculate the time-dependent safety factor of the slope. The results show that the "L" shaped deterioration of rock strength over time makes the factor of safety for creeping slopes lower than for excavation only, which is more consistent with the actual engineering. The reinforced slope still has the risk of instability due to the prestress loss of anchor cable. Four kinds of reinforcement control schemes of anchor cable are compared and selected, on the premise of meeting the safety production in the whole life cycle, the scheme with the best economic benefit is obtained.