TRAMM project Ruedlingen experimental landslide dataset, Switzerland

A landslide testsite dataset related to pore water pressure perturbations on the stability of unsaturated silty sand slopes leading to the initiation and propagation of the shear deformations and eventual rapid mass movements. This project was initiated and led by the Institute of Geotechnical Engineering (IGT) of the Swiss Federal Institute of Technology (ETH Zurich) and was incorporated in a Swiss national (TRAMM) and a European Union (SafeLand) multidisciplinary research project. Field site: The experimental slope is 7.5 m wide by 35 m long, located in the Swiss lowlands on an east facing slope over-looking the river Rhine, at an altitude of ~ 350 masl. Originally there were forestry covertures of circa 80%, heights of 5-20 m. Shrubs up to 1-5 m high and a free herb layer covered ~ 50% of the surface. The average gradient was determined to be from 38° to 43° with a slightly concave surface. The underlying rock consists mainly of Molasse, which is formed by alternate layers of sea deposits under the Tethys Sea (Seawater Molasse) and land deposits (Freshwater Molasse). Several augured samples, as well as an outcrop of the bedrock about 20 m above the selected field, revealed horizontal layering of fine grained sand- and marlstone at the test site. The sandstone was later proven to be highly permeable and fissured. Grain-size distributions were determined and the soil was classified as medium-low plasticity silty sand. Site instrumentation:Measurements of soil suction, groundwater level, soil volumetric water content, rain intensity and soil temperature were taken and combined with geophysical monitoring using Electrical Resistance Tomography (ERT) and investigations into subsurface flow by means of tracer experiments. Deformations were monitored during the experiment, both on the surface via photogrammetrical methods and within the soil mass, using a flexible probe equipped with strain gauges at different points and two axis inclinometers on the top and acoustic sensors. Instruments were installed mainly in three clusters at depths of 15, 30, 60, 90, 120, and 150 cm below the ground surface over the slope, including jet-fill tensiometers, TDRs, Decagon TDRs, piezometers, soil temperature sensors, deformation probes, earth pressure cells, acoustic sensors and rain gauges. A ring-net barrier (provided by Geobrugg AG) was set up at the foot of the slope to protect the road. Experiments: A sprinkling experiment was carried out in September 2008 to investigate the hydrological and mechanical response of the slope (Experiment 1), followed by a second one to trigger a landslide in March 2009 (Experiment 2). Publications 1. Lehmann, P., F. Gambazzi, B. Suski, L. Baron, A. Askarinejad, S. M. Springman, K. Holliger, and D. Or (2013), Evolution of soil wetting patterns preceding a hydrologically induced landslide inferred from electrical resistivity survey and point measurements of volumetric water content and pore water pressure, Water Resour. Res., 49, 7992–8004, doi:[10.1002/2013WR014560](http://dx.doi.org/10.1002/2013WR014560). 2. Springman, S. M., Kienzler, P., Casini, F., & Askarinejad, A. (2009). Landslide triggering experiment in a steep forested slope in Switzerland. In 17th International Conference of Soil Mechanics and Geotechnical Engineering, Alexandria, Egypt (pp. 1698-1701). doi: [10.3233/978-1-60750-031-5-1698](http://dx.doi.org/10.3233/978-1-60750-031-5-1698)本滑坡试验场数据集聚焦于孔隙水压力扰动对非饱和粉砂质砂边坡稳定性的影响机制，涵盖剪切变形的萌生、扩展直至最终发生快速块体滑移的全过程。 本项目由瑞士联邦苏黎世联邦理工学院（ETH Zurich）岩土工程研究所（IGT）发起并主导，纳入瑞士国家级TRAMM项目与欧盟SafeLand多学科研究计划体系。 试验场地： 试验边坡宽7.5米、长35米，地处瑞士低地一处朝东的坡地，俯瞰莱茵河，海拔约350米（meters above sea level，masl）。该区域原植被覆盖率约80%，林木高度5-20米；高度1-5米的灌木与草本层覆盖约50%的坡面表面。坡面平均坡度介于38°至43°之间，整体呈微凹形态。 试验场下伏岩层主要为磨拉石（Molasse），由特提斯洋时期的海相沉积（海相磨拉石）与陆相沉积（陆相磨拉石）互层构成。通过多组钻探取样，以及试验场上方约20米处的基岩露头观测，发现试验场内细砂岩与泥灰岩呈水平层理分布。后续测试表明该砂岩具有高渗透性且发育裂隙。通过粒度分布测试，该土体被归类为中低塑性粉砂质砂。 现场监测仪器： 本试验开展了土体吸力、地下水位、土体体积含水率、降雨强度与土体温度的监测，并配合采用电阻率层析成像（Electrical Resistance Tomography, ERT）开展地球物理监测，同时通过示踪试验开展地下渗流过程研究。试验期间同步开展坡面变形监测：地表变形采用摄影测量法进行观测；土体内部变形则通过布设多点应变计的柔性探头、顶部双轴倾角计及声学传感器进行监测。 监测仪器主要沿坡面按三组阵列布设，埋设深度分别为地表下15、30、60、90、120及150厘米，涵盖注水式张力计、时域反射仪（Time Domain Reflectometry, TDR）、Decagon品牌时域反射仪、孔隙水压力计、土体温度传感器、变形探头、土压力盒、声学传感器及雨量计。坡脚处布设了由Geobrugg AG公司提供的环形防护网，用于保护下方道路。 试验内容： 试验分为两次：2008年9月开展首次喷淋试验（试验1），以探究边坡的水文与力学响应；2009年3月开展第二次喷淋试验（试验2），旨在触发滑坡。 相关出版物： 1. Lehmann, P.、Gambazzi, F.、Suski, B.、Baron, L.、Askarinejad, A.、Springman, S. M.、Holliger, K.与Or, D.（2013），《基于电阻率探测与体积含水率、孔隙水压力点测量结果推求水文诱发滑坡前的土体湿润模式演化》，*Water Resources Research*，49卷，7992–8004页，DOI：10.1002/2013WR014560。 2. Springman, S. M.、Kienzler, P.、Casini, F.与Askarinejad, A.（2009），《瑞士陡峭林坡的滑坡触发试验》，收录于第17届国际岩土力学与岩土工程大会，埃及亚历山大，第1698–1701页，DOI：10.3233/978-1-60750-031-5-1698。