季节性循环冻融下岩质边坡稳定性分析  

Stability analysis of rock slopes under seasonal cyclic freeze-thaw

作　　者：王迪 何玉蝶 殷维 Wang Di;He Yudie;Yin Wei(Hunan Center of Natural Resources Affairs;Hunan Provincial Geological Disaster Survey and Monitoring Institute)

机构地区：[1]湖南省自然资源事务中心 [2]湖南省地质灾害调查监测所

出　　处：《黄金》2025年第1期69-74,共6页Gold

基　　金：自然资源部部省合作试点项目(2023ZRBSHZ056);湖南省自然资源厅地质勘查项目(BSDZSB43202401)。

摘　　要：为探究循环冻融对岩质边坡稳定性的影响,以中国东北某矿山受季节性循环冻融影响的岩质边坡为研究对象,考虑-5℃、-10℃、-15℃、-20℃4种冻融温度梯度,探究1,3,5,7次循环冻融下岩体力学特性劣化规律,并基于MSDP准则开展岩质边坡稳定性评价。研究结果表明:随着冻融温度梯度降低和循环冻融次数增加,试样内部冻缩加剧,试样抗压强度降低2.9%~20.3%,抗拉强度降低6.1%~24.8%,内聚力和内摩擦角分别降低6.5%~13.7%、2.2%~17.3%;当冻融温度梯度固定时,试样拉压力学性能随循环冻融次数增加出现大幅度降低,再次回升后趋于稳定,3次完整循环冻融下试样力学特性降幅最大。疲劳损伤作用下试样内部裂隙不断扩张发育,间断形的裂纹逐渐衍生贯通,裂纹数量随循环冻融次数的增加而增多,细观角度分析冻融对岩体强度劣化的实质是循环冻融下产生的疲劳损伤。基于MSDP准则下求算出的安全系数小于常规极限平衡法求算的安全系数。冻融温度-20℃、循环冻融7次时安全系数最低,循环冻融作用下,试样内部发生了不可逆的结构性损伤,试样强度劣化后抗滑力下降,边坡安全系数随之降低。计算结果可为循环冻融作用下岩质边坡稳定性评价提供参考。To investigate the effect of cyelic freeze-thaw on the stability of rock slopes,this study examines a rock slope in a mining area in Northeast China affected by seasonal cyclie freeze-thaw.4 freeze-thaw temperature gradients(-5℃,-10℃,-15℃,and-20℃)and 1,3,5,and 7 freeze-thaw cycles were considered to explore the deterioration pattern of rock mass mechanical properties.The stability of the rock slope was evaluated based on the MSDPcriterion.Results indicate that with decreasing freeze-thaw temperature gradients and increasing cyclic freeze-thaw,intemal frost shrinkage intensified,leading to a decrease in compressive strength by 2.9%-20.3%,tensile strength by 6.1%-24.8%,cohesion by 6.5%-13.7%,respectively and internal friction angle by 2.2%-17.3%.For fixed freeze-thaw temperature gradients,the tensile and compressive mechanical properties of samples decreased significantly with increasing cyclic freeze-thaw,showed a recovery,and then stabilized.The largest reduction in mechanical properties occurred after 3 complete freeze-thaw cycles.Fatigue damage caused the development and propagation of intemal cracks,with discontinuous cracks gradually extending and connecting.The crack quantity increases with cyelic freeze-thaw.According to microscopic analysis,the essence of rock mass strength deterioration is fatigue damage induced by cyclic freeze-thaw.Safety factors calculated using the MSDPcriterion were lower than those determined by conventional limit equilibrium methods.The lowest safety factor was observed at-20℃after 7 freeze-thaw cycles.Under cyclic freeze-thaw,irreversible structural damage occurs inside the test samples,leading to decreased sliding resistance due to deteriorated test sample strength,ultimately lowering slope safety factors.These findings provide a reference for evaluating rock slope stability under cyclic freeze-thaw.

关 键 词：循环冻融 温度梯度 抗压强度 抗拉强度 极限平衡理论 边坡工程 稳定性分析 

分 类 号：TD854.6[矿业工程—金属矿开采]