滑坡立体监测法

THE WAY OF STEREOSCOPIC MONITORING OF LANDSLIDES

本文从时空,方法手段这种广义的立体测量上,集各种变形于一体,探讨监测滑坡变形的本质.从孕育、成熟,到休止。消失一系列滑坡发育过程中准确地捕捉变形形迹,把握位移动向,作出稳定性评价。寻求变形趋势及其规律,进行预测预报是多年来滑坡监测中的研究课题.本文介绍了近年来逐步形成的一种较理想的立体监测法.

The way of stereoscopic monitoring of landslide puts stress on time-space effect of landslide monitoring. According to different seasonal landslide, the dilTerent method of survey is used as to pay attention to a certain developing forms. Thus we can extensively find out and understand the whole developing process of the landslide.In monitoring of initial stage slide, we use the geological method and some precise instruments by which we can distinguish correctly and make a distinction between the landslide structure and geological structure, and give an answer whether the mountain body is stable.From point of view of structure, landslide is a geological mass enclosed by texture plane of overlain stratum, or is a body of special 'secondary structure', not like geological structure which is the primary structure produced by crust movement. Therefore, they must have their inherent feature , although some slide are quite similarly with texture, or some elements are wholly developed on the track of the surface of ancient geological texture.Landslide having been characterized, dynamic survey can be carried out, by which the movement and the state of a landslide, that is, 'moving' and 'static' can be observed.The deep-seated displacement monitoring, is an effective means to understand the internal deformation of the landslide. The major meanings for monitoring deep displacement as follows: exactly confine the place of sliding surfaces which are acting; the number of sliding zones and the thickness of the deformation zone within sliding body; exactly understand deforming vector in different depths at any lime; discover developing tendency by revealing the deep deformation; provide the scientific basis for engineering design and forecasting of slides, etc.In dynamic survey, it is very important to define exactly the slide direction, and above all, the slide direction moving in broken line or curver. The spiral sensor is a instrument monitoring spiral deformation for any depths or whole landslide body, that is ,the direction value corrected can be gathered at the first time, and the spiral value can be gathered at any times.Pore water pressure remains in close relationship with development of slide specially fast slip slide. A Foreign expert thinks that frictional heat generated within fluid-saturated landslide. Slip zones can create an increase in pore fluid pressure. This rise in fluid pressure is enhanced by large values of friction coefficient, initial porosity and slide displacement and by small values of slip zone's thickness and compressibility. If maintained under conditions of fast slip and small wall rock permeability and shear dilatancy fluid pressure rise can reduce rapid frictional strength loss during sliding. Moderate sliding can thereby be converted under certain conditions into catastrophic descent.