四川省万县市豆芽棚滑坡

豆芽棚滑坡体长５００ｍ，宽１５０ｍ，平均厚１０─１５ｍ，体积１００万ｍ￣３．主滑方向３０°。滑坡前缘海拔１５０ｍ，后缘海拔２００ｍ，本滑坡是在斜坡遭人为破坏（加载）后由降雨诱发的。滑坡防治措施主要拟采取减载和布设抗滑桩。     

论滑坡学

滑坡学可分为理论滑坡学和应用滑坡学．前者的分支有：滑坡发生学、滑坡运动学、滑坡组构学、滑坡形态学、滑坡断代－周期学、滑坡分类学、滑坡分布学、滑坡制图学、滑坡编目学和滑坡数据库系统等．应用滑坡学含滑坡研究方法论、技术手段和滑坡防御工程等．     

Morphology and internal structure of a dormant landslide in a hilly area: The Collinabos landslide (Belgium)

This study attempts to reconstruct the history of the Collinabos landslide, a landslide with a fresh morphology that is representative for more than 150 dormant, deep-seated (> 3 m) landslides in the Flemish Ardennes (Belgium). A geomorphological map was created based on LIDAR (Light Detection and Ranging)-derived maps and detailed field surveys. The map showed that the landslide consisted of three zones with significant differences in surface topography. The northern landslide zone 1 is characterised by at least five reverse slopes, whereas zones 2 and 3, the southern landslide zones, have only two reverse slopes and a convex foot. Electric resistivity profiles measured in zones 1 and 2 revealed that the differences in surface topography were not related to differences in internal structure as both parts of the landslide were initiated as a rotational earth slide with a surface of rupture at 15 m deep, where the displaced material broke apart in two blocks. However, two shear surfaces of reactivations within landslide debris were only distinguished in the accumulation area of zone 1. The observed differences in surface morphology can be caused by a temporary conversion of a forest into cropland in zone 2. It is suggested that reverse slopes of smaller reactivations within landslide debris were obliterated during the agricultural activities. AMS radiocarbon dating of organic material found in ponds located in reverse slopes generally resulted in relatively recent dates (i.e. 1400–1950 Cal AD) suggesting that several of the small local reactivations occurred in that period. One dating at 8700–8440 Cal BP of organic matter collected in a reverse slope in zone 1 suggests that an initiation under periglacial conditions cannot be excluded for the Collinabos landslide. By combining different technologies, this study provides valuable information for a better understanding of dormant landslides.     

裂纹深度和形状对构件断裂韧度的影响

在弯曲疲劳试验机上对几组包含有不同 a/ w值的贯穿裂纹和不同 a、c值的半椭圆裂纹的构件进行弯曲疲劳实验。结果表明 ,对于 60 Si2 Mn A钢来说 ,无论是表面裂纹还是贯穿裂纹 ,在浅裂纹情况下 ,其断裂韧度值比深裂纹高出 2 5%左右。当 a/ w值大于 0 .1时 ,无论 a/ w如何变化 ,KIC值基本保持不变。裂纹形状对断裂韧度的影响也不明显。     

水利工程震害中土工结构低应力破坏实例分析

实际工程活动与低应力下土石料工程性质密切相关。总结了与低应力条件相关的工程活动,在总结分析以往地震中堤防和坝体滑坡案例的基础上,指出滑坡深度通常小于7 m,其上覆有效应力大多小于100 kPa。在对106组地震液化数据资料分析的基础上,指出地基液化大多发生在上覆有效应力低于100 kPa的低应力条件下。在目前的研究中,通常只关注中、高应力条件下土石料的工程性质。在应用中低应力区的土石料计算参数取值通常与中、高应力条件下获得的强度和变形参数一致,而高、低应力条件下土石料的强度和变形特性是不同的,这种计算参数取值方法的适用性存在疑虑。因此,研究低应力条件下土石料的工程性质,探讨数值计算中低应力条件下土石料计算参数的取值方法,具有重要的工程意义和科学价值。     

三峡库区白水河滑坡险情预警方法研究

在分析滑坡时间预测预报及险情预警级别划分的基础上,以三峡库区白水河滑坡险情预警为例,讨论了把滑坡宏观前兆信息与关键部位监测点的变形速率及其相关影响因素有机结合和集成的滑坡险情预警综合预报方法。     

灰色GM(1,1)残差修正模型在滑坡预测中的对比应用

在传统GM(1,1)模型的基础上,经过不同方式的残差修正,分别建立了一阶残差修正GM(1,1)模型和二阶残差修正GM(1,1)模型。根据滑坡的监测资料,对变形曲线为光滑型滑坡(如黄龙西村滑坡、某滑坡)和阶跃型滑坡(如新滩滑坡、洒勒山新滑坡)分别建立了传统GM(1,1)模型和一阶、二阶残差修正模型,并对不同滑坡各模型的预测精度进行了分析比较。结果表明,残差修正GM(1,1)模型的预测精度明显高于传统GM(1,1)模型的预测精度。对变形曲线为光滑型的滑坡,二阶残差修正GM(1,1)模型的预测精度一般高于一阶残差修正GM(1,1)模型的预测精度;对变形曲线为阶跃型的滑坡,一阶残差修正GM(1,1)模型的预测精度高于二阶残差修正GM(1,1)模型的预测精度。     

Application of the SHETRAN basin‐scale,landslide sediment yield model to the Llobregat basin,Spanish Pyrenees

The first application of the SHETRAN basin‐scale, landslide erosion and sediment yield model is carried out for a major landsliding event in the upper 505 km² of the Llobregat basin, in the eastern Spanish Pyrenees, in November 1982. The model simulates the spatial distribution of shallow landslides and their sediment yield. Acknowledging uncertainty in the model parameter evaluation, the aim of the application was not to reproduce the observed occurrence of landslides as accurately as possible with one simulation, but to bracket the observed pattern with several simulations representing uncertainty in the key input conditions. Bounds on the landslide simulations were thus determined as a function of uncertainty in the vegetation root cohesion (used in the model factor of safety calculations). The resulting upper bound considerably overestimates the observed pattern (17 000 landslides compared with an observation of around 700), but it reproduces several of the principal clusters in the observed pattern. The lower bound contains around 500 landslides. The sediment yield estimates (2670–14 630 t km^?2) are comparable to measurements elsewhere in the Pyrenees for extreme events. The results demonstrate an ability to simulate the basin‐scale landslide response to a rainfall event and the resulting sediment yield. They also highlight the need for further research in setting the uncertainty bounds and in avoiding large overestimates of landslide occurrence arising in part from a current inability to model small‐scale controls for a basin of the given size. Copyright © 2006 John Wiley & Sons, Ltd.     

Characteristics of the boundary layer at the bottom of a solitary wave

The results of direct numerical simulations of the boundary layer generated at the bottom of a solitary wave are described. The numerical results, which agree with the laboratory measurements of Sumer et al. (2010) show that the flow regime in the boundary layer can be laminar, laminar with coherent vortices and turbulent. The average velocity and bottom shear stress are computed and the results obtained show that the logarithmic law can approximate the velocity profile only in a restricted range of the parameters and at particular phases of the wave cycle. Moreover, the maximum value of the bottom shear stress is found to depend on the dimensionless wave height only, while the minimum (negative) value depends also on the dimensionless boundary layer thickness. Diagrams and simple formulae are proposed to evaluate the minimum and maximum bottom shear stresses and their phase shift with respect to the wave crest.     

从卫星图像上认识西藏易贡滑坡

2000-04-09中国西藏波密县扎木弄沟发生了巨型山体崩滑事件,堵江截流形成堰塞湖,最终堰塞湖溃决对下游区域造成了严重的破坏。为分析易贡滑坡发生前后地表长时间演化特征,通过长时序光学遥感影像对易贡滑坡灾前灾后特征进行了解译。结果表明,易贡滑坡灾前沟头危岩体发育,沟内大量碎屑物质堆积,并且滑坡物源区在灾害发生前几个月已存在局部崩塌,处于不稳定状态。进一步使用合成孔径干涉测量（interferometric synthetic aperture radar,InSAR）技术监测了易贡滑坡区域2015—2019年地表形变,结果表明扎木弄沟整体处于稳定状态,但在局部区域探测到6个不稳定形变体,其中位于易贡滑坡滑源区的形变体规模与形变最大,风险较高,建议持续开展监测。