CT- and multi-monitoring ready thermo-frozen-hydro-mechanical 3D loading system

CT 和多监测就绪热冷冻水机械 3D 加载系统

• 批准号: 500412763
• 金额: --
• 依托单位: Christian-Albrechts-Universität zu Kiel
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2022
• 资助国家: 德国
• 起止时间: 2021-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/500412763?language=en
• 关键词: CT; multi; monitoring; ready; thermo

In view of the upcoming climate change, the analysis of frozen soil materials is of fundamental importance for the adaptation or mitigation in urban areas as well as for the understanding of occurring geological phenomena. The currently existing permafrost soils are essential in securing the organic carbons encapsulated therein and in stabilizing the existing soil structures, such as constantly and seasonally frozen soils (cryosols) in the cryosphere, embankments, foundations, due to the high rigidity of the subsoil. Here, the basic understanding of changing the coupled cryo-hydro-mechanical soil properties must be improved, so that in addition to the changed chemical, biological processes through the thawing or the transition of the cyclical, alternating thawing / freezing of upper cryosols, the resulting hydraulic, mechanical Changes such as weathering, loss of stiffness and strength, frost-related mixing and erosion can be assessed and modeled. Changes in the cryopedogenic processes such as ice segregation, ice accumulation and cryometamorphosis under alternating thawing / freezing are also unknown.In the adaptation of urban life and the mitigation of increasing urban heat hotspots, the cooling of infrastructures becomes more important. To do this, urban ice stores must be built on a geological scale. Initial research on this is already in progress. From a structural engineering point of view, freezing processes with the load-bearing capacity or protection against failure are known. Cyclical freezing processes, such as those required for the use of ice storages, are completely unknown in terms of their effects. The effects of cyclical freeze-thaw hysteresis on the volumetric pore space and structure changes, in the Atterberg limits or mechanical strength and compressibility degradations have hardly been analyzed and have significant effects on sediments with a larger proportion of fine particles. Secure geomechanical forecasts for these sediments for cyclical freeze-thaw cycles are not yet possible.For the modeling of the cyclic cryo-hydro-mechanical material behavior of frozen soils, a large number of different experimental tests are to be carried out, for which a previously non-existent laboratory device is to be purchased. For the experimental 3D analyzes of the soil samples, a 3-dimensional pressure system for cyclical cryo-thermo-hydro-mechanical loading is to be acquired, which in addition to the cyclical freezing / thawing, the additional installation of further monitoring devices (digital cameras for particle image Velocity, thermography cameras, laser technology, μCT's, radar, etc.) are allowed directly on the sample and during the test process, so that local changes in the structure can be recorded in high resolution as tomography or surface plot and transferred to the modeling.

鉴于即将到来的气候变化，冻土材料的分析对于城市地区的适应或缓解以及对正在发生的地质现象的理解具有根本的重要性。由于底土的高刚性，目前存在的永久冻土在保护其中封装的有机碳和稳定现有土壤结构方面是必不可少的，所述土壤结构例如是冰冻圈中的持续和季节性冻结的土壤（冰冻溶胶）、填料、基础。在这里，改变耦合的低温-水力-力学土壤特性的基本理解必须得到改善，以便除了通过解冻或循环的过渡改变化学，生物过程，交替解冻/冻结上层冻土，由此产生的水力，机械变化，如风化，刚度和强度的损失，霜冻相关的混合和侵蚀可以评估和建模。冻融交替条件下的冰分离、冰积累和低温变态等低温致热过程的变化也是未知的。在适应城市生活和缓解日益增加的城市热热点方面，基础设施的冷却变得更加重要。要做到这一点，城市冰库必须建立在地质规模上。这方面的初步研究已经在进行中。从结构工程的角度来看，具有承载能力或防止破坏的冷冻过程是已知的。循环冷冻过程，如使用冰储存所需的过程，就其影响而言是完全未知的。循环冻融滞后对体积孔隙空间和结构变化的影响，在Atterberg极限或机械强度和压缩性退化几乎没有分析，并具有较大比例的细颗粒沉积物的显着影响。对这些沉积物进行循环冻融循环的安全地质力学预测尚不可能。为了模拟冻土的循环低温-水力-力学材料行为，需要进行大量不同的实验测试，为此需要购买以前不存在的实验室设备。对于土壤样品的实验性3D分析，将获得用于循环低温-热-流体-机械载荷的三维压力系统，除了循环冻/融之外，还额外安装其他监测设备（用于粒子图像速度的数字相机、热成像相机、激光技术、μCT、雷达等）。允许直接在样品上和测试过程中进行，这样结构中的局部变化可以以高分辨率记录为断层扫描或表面图，并转移到建模中。