A procedure for landslide susceptibility zonation by the conditional analysis method

Numerous methods have been proposed for landslide probability zonation of the landscape by means of a Geographic Information System (GIS). Among the multivariate methods, i.e. those methods which simultaneously take into account all the factors contributing to instability, the Conditional Analysis method applied to a subdivision of the territory into Unique Condition Units is particularly straightforward from a conceptual point of view and particularly suited to the use of a GIS. In fact, working on the principle that future landslides are more likely to occur under those conditions which led to past instability, landslide susceptibility is defined by computing the landslide density in correspondence with different combinations of instability factors. The conceptual simplicity of this method, however, does not necessarily imply that it is simple to implement, especially as it requires rather complex operations and a high number of GIS commands. Moreover, there is the possibility that, in order to achieve satisfactory results, the procedure has to be repeated a few times changing the factors or modifying the class subdivision. To solve this problem, we created a shell program which, by combining the shell commands, the GIS Geographical Research Analysis Support System (GRASS) commands and the gawk language commands, carries out the whole procedure automatically. This makes the construction of a Landslide Susceptibility Map easy and fast for large areas too, and even when a high spatial resolution is adopted, as shown by application of the procedure to the Parma River basin, in the Italian Northern Apennines.     

Movement of the Shuping landslide in the first four years after the initial impoundment of the Three Gorges Dam Reservoir, China

The Shuping landslide was reactivated by the initial impoundment of the Three Gorges Dam Reservoir, China in June 2003. For purposes of landslide disaster mitigation in the reservoir area and identification of landslide movement and deformation caused by reservoir level changes, a monitoring system mainly consisting of drum-style extensometers was installed in the eastern part of the Shuping landslide. Systematic monitoring was started in August 2004 with installation of 13 extensometers above the waterline after the initial impoundment. In August 2006, 11 more drum-style extensometers were installed above the high waterline (175 m) and five flexible extensometers were installed along a longitudinal section in the elongation to low waterline. In this paper, the monitoring results from August 2004 to July 2007 are presented and the deforming of the Shuping landslide caused by both reservoir level changes and rainfall is examined.     

三峡水库区巫山县淌里滑坡监测与变形分析

淌里滑坡是三峡水库区地质灾害防治监测预警工程Ⅱ期专业监测点。监测方法为地表位移监测及滑体深部位移监测,同时开展长期地表宏观变形迹象监测调查。通过3a来监测资料的对比分析,各GPS变形监测点均在水平及垂直方向上有变形。即2007年2月位于滑坡前缘的WS-74、WS-75点水平位移分别达到726.91mm及170.88mm,平均年变形速率分别为340mm和80mm;位于滑体下部的WS-75钻孔滑带位置变形明显。该钻孔在2005年5月由于深部位移变形超出测试量程而无法继续监测。在2003年10月至2005年5月20个月内,该钻孔滑带位置累计位移量达46mm以上,月平均变形率达2.3mm。以此变形速率发展,至2006年12月,滑带累计位移变形量将在100mm左右。滑坡的变形集中在滑坡的前缘地带及次级滑坡,从2003年至今,宝子滩崩滑体附近已有将近20×10^4m^3的崩塌堆积层滑入江中。目前滑坡处于匀速变形阶段,为不稳定状态,滑坡区内的4户18人和宝子滩民用码头的安全受到威胁。     

化学灌浆在贵州岩溶山区滑坡治理中的应用

随着公路建设规模的扩大,在贵州岩溶山区边坡及滑坡出现的数量越来越多,治理难度也越来越大。如何用一种经济、施工简便的方法解决贵州岩溶山区滑坡治理问题,成为贵州公路建设中亟待解决的一个重要课题。文章对化学灌浆法在贵州某高速公路滑坡治理中的运用进行试验探索,解决了地层能否灌浆处理;地层灌浆处理时,需要何种浆液材料;采用多大的压力,灌入多少浆液等问题。并在工程治理中选取75个孔做灌浆试验。根据试验确定了灌浆扩散半径、孔距、排距等参数。通过探井开挖试验、标准贯入试验、声波波速测试等检测方法进行灌浆治理效果的检测评价,从检测结论可知,该方法具有很好的效果。为了比较其经济性,还作了3种滑坡治理方案的经济技术对比。从对比结果可知,化学灌浆技术具有很强的经济优势。因此,该技术在岩溶山区的滑坡治理中有很好的适用性及应用前景。     

基于地矿点源信息系统的空间数据模型研究

随着地矿工作信息化水平的提高,为了管理和组织海量的空间数据,空间数据模型的有效构建成为地矿信息工作者面临的实际问题。简要介绍了空间数据模型的分类和层次结构,着重讨论了面向对象数据模型以及用统一建模语言构建面向对象数据模型的方法。     

CNOP-P-based parameter sensitivity for double-gyre variation in ROMS with simulated annealing algorithm

Reducing the error of sensitive parameters by studying the parameters sensitivity can reduce the uncertainty of the model,while simulating double-gyre variation in Regional Ocean Modeling System(ROMS).Conditional Nonlinear Optimal Perturbation related to Parameter(CNOP-P)is an effective method of studying the parameters sensitivity,which represents a type of parameter error with maximum nonlinear development at the prediction time.Intelligent algorithms have been widely applied to solving Conditional Nonlinear Optimal Perturbation(CNOP).In the paper,we proposed an improved simulated annealing(SA)algorithm to solve CNOP-P to get the optimal parameters error,studied the sensitivity of the single parameter and the combination of multiple parameters and verified the effect of reducing the error of sensitive parameters on reducing the uncertainty of model simulation.Specifically,we firstly found the non-period oscillation of kinetic energy time series of double gyre variation,then extracted two transition periods,which are respectively from high energy to low energy and from low energy to high energy.For every transition period,three parameters,respectively wind amplitude(WD),viscosity coefficient(VC)and linear bottom drag coefficient(RDRG),were studied by CNOP-P solved with SA algorithm.Finally,for sensitive parameters,their effect on model simulation is verified.Experiments results showed that the sensitivity order is WD>VC>>RDRG,the effect of the combination of multiple sensitive parameters is greater than that of single parameter superposition and the reduction of error of sensitive parameters can effectively reduce model prediction error which confirmed the importance of sensitive parameters analysis.     

三峡库区巫山县新城址工业区滑坡的成因机制研究

移民是三峡工程成败的关键。巫山县新城址的地质问题是当前学术界关注和争议的焦点,也是库区具有普遍性的问题。本文根据滑坡的地貌和结构特点,应用岩体结构控制论,提出了滑坡的成因机制,认为滑坡经历了先期滑动和后期改造的过程。这种滑坡成因机制的提出为解决三峡库区众多疑难地质问题奠定了基础。     

滑坡预报的几个基本问题

在滑坡预报研究中,必须首先解决与预报密切相关的一些基本问题。否则,往往导致预报误差很大或者预报失败。根据作者的初步探索,本文重点讨论了滑坡预报的分类及定义、预报参数及其监测点的选取、变形突变现象的分析与处理以及斜坡变形阶段的定量判断等基本问题。     

抚顺西露放边坡工程地质灾害浅析

根据抚顺西露天矿地质灾害及其成灾性的现场调查和室内试验测试数据资料,对边坡地质灾害类型进行归纳、分析。     

布格重力异常建模反演在二连盆地油气勘探中的应用

二连盆地由众多小凹陷组成,伊和凹陷是其中之一.重力资料在盆地"探边摸底"、"定凹选带"等方面发挥着重要作用.本文基于布格重力异常资料,利用2.5D建模反演技术对其中横跨主洼槽的两条测线进行可视化建模及正演拟合.其中,初始模型的几何参数取自二维地震解释结果;物性参数中的纵向密度取自测井声波波速与密度的相关公式.正演拟合为建模反演技术的关键环节,密度横向变化,是在拟合过程中通过人机交互试错调整实现.通过正演拟合,揭示了主洼槽沉积层横向和纵向均存在较大的密度不均匀性,主洼槽有利于油气生成.与地震解释结果对比,二者在赛汉组-第四纪、腾格尔组深度相差不大,但凹陷底部拟合结果与地震解释结果有明显差异.通过钻井结果验证,正演拟合各沉积层深度与钻井揭示的各层深度结果一致,二维地震解释结果偏浅,其可能原因是时深转换选取的速度值偏小造成.