地下工程流–固耦合试验新技术及其在充填型岩溶管道突水模型试验中的应用

在地质力学模型试验技术的基础上,根据大型交通、水利水电及矿山工程的需要,开展大比尺流–固耦合模型试验技术研究,包括新型流–固耦合相似材料、三维可视化固液耦合试验系统以及多物理场信息监测分析技术。提出了流–固耦合相似材料的配制原则,选择了多种性能耦合较小的调节剂,实现了强度、渗透性、重度等指标的独立调节,大大提高了材料的相似度,保证材料能够在水长期作用下保持稳定的性质,很好地模拟中、低强度的岩体、破碎带及充填物。三维可视化固液耦合试验系统具备了自动化静力加载和数字化水压加载功能,实现了复杂地质条件下有压水体与相似材料的大面积直接作用,为流—固耦合条件下渗流和突涌水过程的模拟提供了可视化的试验场所。光纤技术、电阻元件柔性防水技术和自动化数据采集分析系统,实现了水环境下模型体内部渗压、应变和位移的精确采集和分析。最后,依托湖北省保康至宜昌高速公路尚家湾隧道,开展了充填型岩溶管道失稳突水的大比尺三维模型试验研究,真实再现了工程中的突涌水过程,揭示了充填型岩溶管道突水的灾变特征。流–固耦合试验新技术得到成功应用,为试验的顺利进行提供了技术保证。

New technology for fluid-solid coupling tests of underground engineering and its application in experimental simulation of water inrush in filled-type karst conduit

According to the needs of large transportation, water conservancy and hydropower and mine projects large-scale fluid-solid coupling model tests on new technology are performed based on geomechanical model tests. This technology includes three aspects, new fluid-solid coupling similar materials, 3D visual solid-liquid coupling test system, and monitoring-analysis technique of multi-physics fields. The preparation principle of the fluid-solid coupling similar materials is proposed. Various slightly coupling regulators are chosen to add to the materials, making the performance parameters of strength, permeability and density regulated separately. The similarity of materials is greatly improved, and the properties of the materials can remain stable under the long-term effect of water. Low-strength and medium-strength rocks, fracture zone and fillings can be accurately simulated by using the materials. With the function of automated static loading and digital water pressure loading, the 3D visual solid-liquid coupling test system realizes direct large-scale interaction between pressure water and similar materials, and provides a visual place for the simulation of seepage and water inrush process under the condition of fluid-solid coupling. The precise acquisition and analysis of seepage pressure, strain and displacement in water environment can be realized by fiber technology, flexible waterproof technology of resistor elements and automatic data acquisition and analysis system. Finally, the 3D large-scale model tests on water inrush in filled-type karst conduit are carried out based on Shangjiawan tunnel in Baokang-Yichang expressway. The process of water inrush is truly reproduced, and the catastrophe characteristics of water inrush in filled-type karst conduit are revealed. The new technology has been successfully used in the model tests and provided technical assurance for good results.