【摘要】 二古溪边坡位于四川省理县狮子坪水电站库区,2013年9月水库蓄水高度升至2 540m后,边坡出现强烈变形,致317国道阻断至今。初步分析边坡在河谷快速下切过程中,坡体内岩体应力释放产生向临空面的位移,由于存在软硬两种岩体,变形过程中产生了不协调变形,软岩的变形位移量大而硬岩较小,致使在硬岩中形成应力集中,当应力大于硬岩强度时,硬岩发生破坏。5.12汶川地震、公路开挖及降雨进一步加剧边坡的倾倒破坏,随后坡体逐步达到应力平衡。通过大量现场地质调查,并结合钻孔岩芯、变形监测对二古溪边坡倾倒变形成因进行研究,结果表明:二古溪倾倒边坡属于软硬岩互层的早期倾倒边坡,在地震作用下边坡岩体造成了损伤,蓄水与强降雨加剧了边坡的变形;目前边坡处于应力调整期,变形将会持续较长的一段时间,蓄水位升高无疑还将加剧其变形。更多还原

【Abstract】 Erguxi toppling slope is located in the reservoir area of Shiziping hydropower station in Sichuan Province.On September 2013 the storage water level was raise up to 2 540 m and the slope deformed strongly and then blocked G317 road.Preliminary analysis shows that during the rapid cutting of valley,the stress release in rock mass leads to displacement towards the free face,and because of hard rock and soft rock,the deformation is uncoordinated.The deformation of soft rock is lager than that of hard rock,resulting in the stress concentration in hard rock,and when the stress is larger than the hard rock strength,hard rock failure happens.The 5.12 Wenchuan earthquake together with highway excavation and rainfall further exacerbated the toppling slope,and then the slope gradually reached a state of stress balance.According to field geological survey,we analyzed the formation mechanism of the toppling slope by means of drilling core and monitoring.Results reveal that the slope is in the early stage of toppling of interbedded soft and hard rocks.The damage of slope rock mass was caused by earthquake and was intensified by water storage and rainfall.At present the slope is in stress adjustment and the deformation will continue for a long period,and also water level rise will no doubt exacerbate its deformation.更多还原