岩质边坡开挖空间块体表征与动态失稳滑落安全稳定性评价

为了研究边坡工程中开挖角度对动态滑落的影响及评价整体安全稳定性,利用现代非接触测量技术,对辽宁境内庄盖高速(庄河-盖州)某边坡进行坡体结构面信息采集,并导入自主研发的GeoSMA-3D系统,建立该岩质边坡的三维裂隙空间实体模型,在工程不同开挖角度下搜索出边坡关键块体。在此基础上,利用二维数值流形法(NMM)程序,模拟不同开挖倾角下边坡断面动态失稳滑落过程,分析评价了工程边坡岩体的安全性与稳定性情况。

Modeling of spatial blocks in rock slope excavation and assessment of the dynamic sliding instability

The paper is aimed at presenting a simulated model of the spatial blocks in rock slope excavation and assessment of the dynamic sliding instability.In this paper we have investigated the dynamic sliding process affected by a different excavation angle and gained necessary data and information of the slope engineering with the advanced non-contact measurement technology(the ShapeMetriX3D system).We have also taken pictures from different points of view and acquired a three-dimensional digital image that can provide relevant information after appropriate processing.At the same time,we have also numerically simulated the spatial entity including the three-dimensional finite random or the fixed discontinuities by using the same system.The so-called GeoSMA3D system is founded on the Block Theory,which has the fractures as finite disk-shaped forms.Later,we have made a comparative study of the key blocks to be identified from the different excavation angles.We have also examined the key blocks of the strongest rock mass and the weakest parts on the basis of the core Block Theory.Actually,so far as we know,the failure of rock mass always begins with the key block or blocks and extends to the other parts of the mass likely to lead to the destruction of the whole mass.The Geo-SMA can help to find out the key blocks in the rock mass and optimize the excavation angle in the design along with some necessary support focused on the above said blocks,so as to maintain the stability of the entire rock mass.In addition,we have also chosen a typical cross-section and made a simulated model of the likely-to-happen or potential sliding instability of the slope blocks by planar Numerical Manifold Method(NMM) code in different excavation angles.As a new numerical model for geotechnical engineering,NMM is by nature a more general approach to attacking the problems of continuity and discontinuity of dynamic and static nature,great displacement as well as small deformation.Thus,it proves out that NMM can be taken as a model of good performance in solving such slope engineering problem.Besides,we have also worked out the essential data through NMM code and make them in diagrams,as the result of comparing the displacements of certain key blocks in x and y axis.Therefore,the two methods above mentioned prove to be worthy for evaluating the security and stability from the two different aspects,since they are not only closely related to the morphology of fractures,but also heavily influenced by the excavation angle.With the certain fracture morphology in our engineering discussion,stability tends to be diminished or decreased with the change of the excavation angles of 45°,60° and 75°.