喜马拉雅山东南地区地质灾害发育规律初步研究

利用遥感手段,结合MapGis,研究了喜马拉雅山东南地区地质灾害的发育情况,发现本区发育的主要地质灾害有滑坡、崩塌、泥石流、冰湖以及堰塞湖。其中崩塌、滑坡、泥石流斜坡地质灾害是本区最重要的地质灾害类型,占到总灾害数量的95.3%。在此基础上对喜马拉雅山东南地区地质灾害发育规律初步研究,发现本区地质灾害的发育在空间上的分布并非均匀,而是具有丛集性的特点。滑坡灾害主要发育在隆子和朗县。泥石流灾害比较严重的有米林、隆子和洛扎3县,而崩塌则主要集中在隆子县。研究发现,本区滑坡发育与地层、地形坡度以及土地类型关系密切,其中修康群、日当组和念青唐古拉群是本区的易滑地层。涅如组由于面积大,其中发育的滑坡较多,但是滑坡的发育率只略高于本区的平均水平。统计表明,16～30的坡度范围是滑坡最容易发生的。大于45以上的坡段很少发生滑坡。灌木林和天然草地这两种土地类型滑坡发育率最高。对于泥石流,研究表明,涅如组中泥石流发育面积最大,发育率也最高。泥石流发育的最适宜坡度也是16～30这样一个坡度范围。冰川和永久积雪区则最易发生泥石流。崩塌发育与地层类型、坡度的关系较为密切,崩塌主要发育在涅如组中,并且集中在坡度大于60以上的陡坡段中。这些初步成果的取得,是以后进行该区地质灾害空间预测的基础。     

模糊综合评判在大水箐泥石流危险度评价中的应用

介绍了宾川县大水箐泥石流灾害的发育特征。选用了7个评价因子对大水箐泥石流危险度进行模糊综合评价,并在求解权重和隶属度中引入了灰色关联法和半梯形分布模型。结果表明,改进后的模糊综合评判法是正确可行的。     

Estimation of lahar and lahar-runout flow hydrograph on natural beds

A numerical model is used to simulate channelized lahars, flowing with a near-constant sediment concentration and volume. Water and debris are usually mobilized in short times and the peak discharge of lahars may reach many thousands of cubic meters per second in a few minutes. A relation for the energy dissipation term must be provided in the model, which in turn depends on debris flow rheology and shape and status of channel bed. A discussion of the form of this term is performed through the simulation of some historical (among the well-documented) lahars and lahar-runout flows with concentrations ranging in a wide spectrum up to 70 percent by volume and irregularly shaped sand and coarser particles dispersed in a fluid matrix of water and fine material. As concentration increases and turbulence decreases, the dissipative term, which, in the first case, is proportional to the square average flow velocity (Manning or Chezy formulation) is well described by a linear dependence on flow velocity, as expected in the laminar case. The numerical reproduction of the examined historical cases suggests that the model can be used for hazard assessment, if some hypotheses are made about lahar hydrograph at the source, its volume, and the shape of the dissipative term.     

我国主要人类工程活动引起的滑坡、崩塌和泥石流灾害

本文概述了我国主要人类工程活动引起的滑坡、崩塌和泥石流灾害的发育分布规律。     

陕南山地滑坡和泥石流分布特征及其相关性

滑坡和泥石流是陕南山地成灾的主要物理地质现象。本文根据野外调查资料和前人研究成果,从地质、地貌、水文工程地质特征、水文气象、人为因素诸方面,简要的分析了陕南山地滑坡、泥石流形成条件、区域分布规律滑坡对泥石流形成的影响和滑坡转化成泥石流的辩证关系。     

Identification of hazard conditions for mudflow occurrence by hydrological model: Application of FLaIR model to Sarno warning system

Mathematical models for forecasting landslides and mudflow movements triggered by heavy rainfalls are useful tools to develop warning systems and hazard mitigation strategy for loss reduction.

In the present paper, an application of Forecasting of Landslides Induced by Rainfalls (FLaIR) hydrological model, correlating the rainfall amount and landslide or mudflow movement occurrences, will be performed. Model application presented here refers to the mudflows of Sarno, Southern Italy, and is based on hourly precipitation data available from a real-time rain gauge installed immediately after the catastrophic event that occurred on May 1998.

The application is extended from October 1998 to May 2002. The main objective is to perform a backanalysis in order to verify the reliability of the proposed scheme for use in a warning system.

Among the most interesting results of the application, the relatively few false alarms for populations given by the model may be highlighted.

The FLaIR model is more useful when it is integrated with a probabilistic model for forecasting precipitation depths during a storm event at an hourly scale. By stochastic modelling of hourly precipitation, it is possible to estimate the probability of reaching the alarm threshold before allowing civil protection actions.     

SPH-based numerical investigation of mudflow and other complex fluid flow interactions with structures

The understanding of mudflow–structure interactions and debris–flow structure interactions is of paramount importance for the rational design of technical countermeasures. However, to date, only a limited number of studies have investigated this subject. We propose here a numerical approach to this topic using a 2D vertical numerical model based on the smoothed particle hydrodynamics (SPH) method. First, we will test the capacity of the model to simulate unsteady free-surface flows of water and viscoplastic fluid in comparison to laboratory experiments. Then, we will use it prospectively, based on a series of simulations of Bingham fluid free-surface propagations, to determine the momentum reduction resulting from the presence of a simple obstacle perpendicular to the direction of propagation and to determine the characteristics of stresses applied to this obstacle in terms of peak pressure and evolution over time.     

基于遥感图像特征的复杂沟系中泥石流的运动及动力学特征分析

根据卫星遥感图像特征,分析了河北省太行山区复杂沟系泥石流的运动及动力学特征,提出了泥石流在支沟中是匀变速(加速)运动,在主沟中是脉冲式运动。阐述了主沟中的脉冲式运动方式是由泥石流能量(动力)积累与释放交替演变的结果,而能量的积累与释放是由主沟两侧地质环境条件所决定的     

北京市北部山区石城镇泥石流沟松散物特点及储量计算模型

总结了石城镇泥石流沟松散堆积物的特点,依据现场调查泥石流一次冲刷的深度,推导出泥石流沟内松散堆积物动储量的计算公式,对已调查的泥石流沟内动物质储量进行了计算,为泥石流的预警和治理提供了基础数据。