Research On Long-term Stability Test Equipment And Similar Simulation Materials For Underground Caverns With Weak Interlayers Containing Water

Rock masses that exist in nature usually contain a variety of rocks and complex geological structural relationships.Therefore,there are many difficulties in studying rock mass engineering problems.Geomechanical model tests tend to assess geotechnical engineering issues.Geomechanical model test equipment and similar materials are the promise and guarantee for carrying out model tests.In the past,model tests involving water mostly utilized indirect fractures to describe hydraulic penetration,and there were few direct water tests,which hardly were reflecting the softening effect of water rock.Weak interlayers often impact negatively on the stability of geotechnical engineering due to their own weaknesses.The water content in the weak interlayers will aggravate the instability of geotechnical engineering.The construction and maintenance of civil engineering have important functional significance.This article is mainly based on the Shandong Province Natural Science Foundation project "Long-term Stability of Water-bearing Interlayer Underground Cavity" and "Study on Long-term Rheological Stability of Caverns with Weak and Thin Interlayers in Inclined Layered Rock Mass",and on the basis of previous research,developed a set of devices that can be applied to the model test of water-bearing interlayer underground cavern.And two similar simulated materials,focusing on the mechanical properties and hydraulic properties of similar materials.The main research contents and conclusions of this article are as follows:(1)This article first introduces the main content and development process of the similarity theory.On this basis,the equation analysis method is utilized to properly derive the similarity theory,and finally the partial similarity criterion applicable to the solid model test is obtained.Considering the participation of water in the model test of underground caverns with water-bearing weak interlayers,the fluid-solid coupling similarity criterion is examined to provide a theoretical basis for future model tests.(2)A set of equipment that can be used for model test of underground caverns with diluted water-containing interlayers has been developed.The equipment is mainly composed of the model frame,hydraulic loading system,non-contact measurement system and cavern excavation automation system.The innovation of the model test equipment is that compared with the traditional model test equipment,in addition to a large model test,after simple disassembly,two small model comparison tests can be performed at the same time,which is the basis of the model test Sexual research is of great significance.The cavern excavation automation system can realize quantitative excavation,timely chip removal,temporary support and real-time monitoring of the cavern,which greatly reduces the adverse influence of manual excavation on the model test.Finally,a static analysis is performed on the model frame with the most stress.From the analysis results,it is known that the designed model frame has excellent stability and can meet the requirements of model tests.(3)Based on the similarity theory,non-hydrophilic similar materials are developed as the principal rock material for the model test of underground caverns with water-containing weak interlayers.The material uses 40-mesh river sand as aggregate,cement and gypsum as cementing material,and organic silicon solution as auxiliary material.Utilize the orthogonal test method to conduct specific research.Three factors(sand rubber ratio,cement-gypsum ratio,organosilicon solution concentration)are established in the experiment.Each factor has 4 levels and a total of 16 groups of experiments.By performing uniaxial compression,splitting,water absorption,softening,permeability,and swelling tests on each group of test pieces,the mechanical properties and hydraulic properties of similar materials were generated.Using the range analysis method and the sensitivity analysis of each factor,the influence degree and trend of different factors on comparable material indexes are obtained.(4)Hydrophilic similarity simulation material is used as the weak interlayer material in the model test of underground caverns with water-containing weak interlayer.The material uses 40 mesh river sand as aggregate,gypsum and kaolin as cementing materials,soybean powder and 801 glue as auxiliary materials.In the orthogonal test,there is also set 3 factors(sand rubber ratio,paste soil ratio,soybean content),each factor has 4 levels,a total of 16 groups of tests.By performing uniaxial compression,splitting,water absorption,softening,permeability,expansion and other tests on each group of test pieces,some mechanical properties and hydraulic properties of similar materials were generated.Using the range analysis method and the sensitivity analysis of each factor,the influence degree and trend of diverse factors on similar material indexes are obtained.(5)The purpose of the model test of underground caverns with weak water-bearing interlayers is to study the long-term stability of the weak water-bearing interlayers and the main rock mass,focusing on basic regularity exploration,so the hydrophilic and nonhydrophilic similar materials studied in this paper are not specific to a specific The rock layer of the engineering project,the similar materials studied in this paper have certain reference significance for the future research of similar similar materials.