关于滑坡稳定性在滑坡安全系数取值中的作用讨论

在工程界存在着滑坡安全系数取值应考虑滑坡稳定性高低、对稳定系数较低的滑坡应采用较大的安全系数的思想。考虑滑坡稳定性的具体方式有两种:①考虑滑坡的实际稳定状态或变形情况;②考虑设计工况下的稳定系数。考虑滑坡稳定性的理由也有两种:①变形急剧势必危害较大;②滑坡在治理后的安全储备可用"安全储备系数"(即下滑力按安全系数放大后的剩余下滑力与下滑力不作改变时的剩余下滑力之比)来衡量,而"安全储备系数"存在着随稳定系数的减小而减小的规律。文章的研究表明,滑坡变形越急剧滑坡危害越大的规律是不存在的,滑坡"安全储备系数"既不能衡量滑坡在治理后的安全储备,也不随滑坡稳定系数的减小而减小,滑坡安全系数与稳定系数无关,将安全系数取值与稳定系数大小挂钩会导致诸多不合理现象产生。因此,滑坡安全系数取值不应考虑稳定系数大小。

Discussion on the role of stability of a landslide in selection of its safety factor

In the civil engineering field,there is the thought that stability of a landslide should be considered in assumption of the set value of its safety factor,and that the lower stability of the landslide,the larger the set value of its safety factor should be.There are two ways of considering stability of a landslide in assumption of the set value of its safety factor: considering its actual stabilie state or its deformational degree and considering its safety factor in the design operating mode.There are two reasons to reorganise the set value of safety factor of a landslide by its stability.The first,extent of injury of a landslide will be higher if its deformational degree is higher.The second,the safety storage of a landslide after treatment could be measured by its "factor of safety storage" and that the smaller safety factor of the landslide,the smaller its "factor of safety storage".My research shows:(1) there is not the law that extent of injury of a landslide will be higher if its deformational degree is higher;(2) safety storage of a landslide after treatment could not be measured by its "factor of safety storage",there is not the law that the lower safety factor of a landslide,the smaller its "factor of safety storage" is;(3) the set value of safety factor of a landslide is unconcerned with its safety factor and(4) connectting assumption of the set value of safety factor of a landslide with its safety factor will result in many reasonless appearance.So stability of a landslide should not be considered in assumption of the set value of its safety factor.