Characterizing Rockwall Weathering from Microclimate, Rock Moisture and Rockfall Acitvity – ClimRock

从微气候、岩石湿度和落石活动表征岩壁风化 – ClimRock

• 批准号: 426793773
• 负责人: Dr. Daniel Dräbing
• 金额: --
• 依托单位: Lehrstuhl für Geomorphologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/426793773?language=en
• 关键词: Characterizing; Rockwall; Weathering; Microclimate; Rock

Rock breakdown by weathering is the first step of the alpine sediment cascade. Weathering processes are influenced by diurnal heating and cooling, wetting and drying, diurnal and seasonal freezing and thawing or seasonal active-layer thawing. Individually or in combination, these processes result in the subcritical or critical propagation of fractures that act to prepare and trigger rockfalls. Rockfall processes are a key agent of alpine landscape evolution but also present hazards to tourists and infrastructure. Nonetheless, thermal- and moisture-driven weathering processes are poorly understood and particularly, temporal and spatial information on moisture in rockwalls are lacking. Improved process understanding is necessary to anticipate trajectories and rates of weathering processes and associated rockfall in light of foreseeable climate change. We follow a conceptual multiscale-model integrating temperature and precipitation/moisture gradients, which depend on elevation and aspect: (1) On laboratory scale, we will simulate temperature cycles, wetting and drying and frost weathering under controlled conditions to quantify cracking activity and develop temperature/moisture-cracking activity relationships, combining AE sensors, crackmeters, moisture and temperature probes and resistivity measurements. (2) On rockwall scale, the lack of information results partially from the difficulty to measure rock moisture in the field. We will monitor temperature, moisture and rock kinematics using temperature and self-developed moisture sensors, crackmeters and meteo stations. We will quantify spatial differences of rock moisture and temperature discontinuously using 2D resistivity surveys and IR photography. The limestone rockwalls in the Dammkar and Dachstein research areas were selected to cover an altitudinal range from 1400 to 3000 m and north and south faces. (3) We will use our results on laboratory and rockwall scale to model rock weathering on mountain scale, applying already tested GIS-based geostatistical and rock mechanical models and simulation tools, to overcome the limitations of currently used purely temperature-driven models. We will compare the results with rockfall data that we will create from repeated Terrestrial Laserscanning surveys. Furthermore, we will adjust our temperature conditions to simulate weathering condition during the Little Ice Age and in 2050 and 2100 by incorporating climate scenarios. The novelty of this project is the investigation of rock weathering across spatial scales, addressing process interactions and integrating rock moisture and rock-mechanical parameters for the first time. This will create new insights on rock weathering and associated rockfall, which are required to understand past and future Alpine landscape evolution and to anticipate future weathering and rockfall trajectories to mitigate Alpine hazards.

岩石风化破裂是高山沉积级联的第一步。风化过程受昼夜加热和冷却、湿润和干燥、昼夜和季节冻融或季节活动层解冻的影响。这些过程单独或组合导致裂缝的亚临界或临界传播，其作用是准备和触发岩崩。落石过程是高山景观演变的关键因素，但也对游客和基础设施造成危害。然而，热和水分驱动的风化过程知之甚少，特别是，在岩壁水分的时间和空间信息是缺乏的。根据可预见的气候变化，有必要提高对过程的理解，以预测风化过程和相关落石的轨迹和速率。我们遵循一个概念性的多尺度模型集成温度和降水/水分梯度，这取决于海拔和方面：（1）在实验室规模上，我们将模拟温度循环，湿润和干燥和霜冻风化在受控条件下量化开裂活动和开发温度/水分开裂活动的关系，结合AE传感器，裂缝仪，湿度和温度探头和电阻率测量。(2)在岩壁尺度上，缺乏信息的部分原因是难以在野外测量岩石水分。我们将使用温度和自主开发的湿度传感器、裂缝仪和气象站监测温度、湿度和岩石运动学。我们将使用二维电阻率测量和红外摄影不连续地量化岩石水分和温度的空间差异。在Dammkar和Dachstein研究区的石灰岩岩壁被选择为覆盖1400至3000米的海拔范围和南北面。(3)我们将使用我们的实验室和岩壁规模的岩石风化模型在山区规模，应用已经测试过的基于GIS的地质统计和岩石力学模型和模拟工具，以克服目前使用的纯粹的温度驱动模型的局限性。我们将比较结果与落石数据，我们将创建从重复的地面激光扫描调查。此外，我们将调整我们的温度条件，以模拟小冰河时期以及2050年和2100年的气候条件。该项目的新奇在于跨空间尺度调查岩石风化，解决过程相互作用，并首次整合岩石水分和岩石力学参数。这将创造新的见解岩石风化和相关的落石，这是需要了解过去和未来的阿尔卑斯山景观演变，并预测未来的风化和落石轨迹，以减轻阿尔卑斯山的危害。