资料简介： Monitoring and modeling of slope movement on rock cliffs prior to failure
N.J. Rosser & D.N. Petley
International Landslide Centre, Institute of Hazard and Risk Research, Durham University, UK
ABSTRACT: In this paper we examine the use of terrestrial laser scan data for monitoring large rock cliffs in ordertoassessthedynamicsoftheslopeconditionpriortofailure. Theassessmentpresentedusesacombination of this terrestrial data and air-borne mapping and imagery to explore the degree to which small-scale precursors to slope failure can be identified, and ultimately used to predict failure. The degree to which data is projected from any given perspective which represents the development of the slope is suggested to be critical. Here we present data that has been collected for four years at monthly intervals from over 35,000 m 3 of near-vertical coastal rock face. This high-resolution data is used to identify characteristic spatial and temporal patterns in rockfall activity notably in the periods leading to large-slope failures. To date in excess of 60,000 discrete events have been recorded ranging from 0.00001 m 3 to 2,500 m 3 . The patterns in the data show similarity with time-dependant models of failure mechanisms, which may enable the prediction of failure occurrence both in time and in space. This interpretation is only reached however with appropriate and, in terms of survey,unconventional treatment. Analysis of the data derived from the laser scanning suggests that given sufficient measurement precision, precursory behavior can be identified and monitored but that the relative viewing angle of the observation compared to the vector of deformation is critical. In this instance pre-failure deformations are manifestastherateofrockfallactivitypriortofailure, inadditiontothedirectmeasurementoftheaccumulation of the strain field across the failing rock face. The monitoring data implies a time-dependent sequence in the occurrence of rock falls in the period leading to the largest failures recorded, often mirroring the hyperbolic increases in movement witnessed in standard displacement monitoring or laboratory simulation prior to failure.The implication is that combining this data with models of failure mechanisms may allow failure time to be forecast from wide-area monitoring of precursory behavior. This ultimately means that a small number of instruments can be employed to monitor large expanses of rock face, providing both spatial and temporal data.These approaches, combined with the time-dependant modeling of precursory activity, have implications for the management of potentially unstable slopes, the understanding of slope failure mechanisms and potentially feed into a new generation of slope failure warning systems applicable to both natural and man-made situations.
在陡倾岩体失稳前监测和模拟边坡运动
N.J. Rosser 和 D.N. Petley
国际滑坡中心，研究所危害和风险的研究，杜伦大学，英国
摘要：在本文中，为了评估的斜坡动态失稳的条件，我们研究对大型陡倾岩体使用地面激光扫描得到监测数据。评估结合采用了地面数据和大气的测绘和图像，探讨了在何种程度上可以识别的小规模的前体斜坡失稳，并最终用于失稳的预测。这种程度上的表现动态斜坡的数据预测从任何方面上来看都是至关重要的。在这里，我们目前已收集了4年中每个月35,000立方米近垂直岩壁的数据。这种高分辨率数据是用来识别特征的时空格局落石活动期间特别是在优先的大斜坡失败。迄今为止，在超过60,000离散型事件记录了从0.00001立方米到2500立方米的变动。该模式中的数据显示了相似的随着时间的推移而模型失稳的机制，从而得知失稳有可能与时间和空间都有关。这种解释只是适当的，且是在调查中，而非传统的处理方式。分析来自激光扫描的数据表明，给予足够的测量精度，前兆现象是可以确定和监督，但相对于视角的观察和比较，载体的变形是至关重要的。在这种情况下预先失稳变形表现为岩崩活动的预先失稳，此外还有在失稳的岩壁上直接测量得到的积累的应变场。监测数据意味着发生在岩瀑期间的时变序列导致了最大的失稳记录，水平位移监测或实验室模拟中的预先失稳的运动记录往往反映了夸张的增长。这意味着，这一数据相结合的模式，失效机理允许用失稳的时间从广大的监测前兆行为来预测。这最终意味着少数仪器可以用来监测大范围的岩面，提供了空间和时间数据。这些做法，包括时间变模型的前兆活动，使对潜在不稳定斜坡的管理，对斜坡失稳的机制和潜在因子的理解融合到一个新的适用于自然灾害和人为的情况的斜坡失稳预警系统。
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